International Journal of Osteopathic Medicine- Volume 14, Issue 1 (March 2011)

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Author: Nicholas Lucas | Robert Moran & Steven Vogel

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Find us on the web: www.intl.elsevierhealth.com/journals/ijos For the complete Guide for Authors please visit www.elsevier.com/ijos Editorial Office: [email protected]

Editors Nicholas Lucas BSc(ClinSci), MHSc(Osteo), MPainMed, Grad Dip Clin Epi Sydney School of Public Health, The University of Sydney, Sydney, Australia Robert Moran BSc, BSc(ClinSci), MHSc(Osteo) Department of Osteopathy, Unitec New Zealand, Auckland, New Zealand Steven Vogel DO The Research Centre The British School of Osteopathy London, UK Editorial Advisor Ann Moore PhD, Grad Dip Phys, Dip TP, FCSP, FMACP, Cert Ed, ILTM School of Health Professions, University of Brighton, East Sussex, UK Editorial Office Journal Manager, International Journal of Osteopathic Medicine, Health Sciences, Elsevier, The Boulevard, Langford Lane, Kidlington, Oxford, OX5 1GB, UK Fax: +44 (0) 1865 843923 Email: [email protected] Book Review Editor Carol Fawkes DO, Lic Ac University of Brighton, East Sussex, UK Editorial Board Peter Gibbons MBBS, DO, DMS-Med, MHSc School of Health Sciences, Victoria University, Melbourne, Australia Janine Leach BSc, PhD, ND, DO, HonMFPH, School of Health Professions, University of Brighton, East Sussex, UK

Michael Patterson PhD College of Osteopathic Medicine (Retired), NOVA Southeastern University, Florida, USA Tamar Pincus BSc, MSc, MPhil, PhD Department of Psychology, Royal Holloway University of London, London, UK International Advisory Board J Louise Adam (NSW, Australia) Peter Baziotis (NSW, Australia) Leon Chaitow (London, UK) Brian Degenhardt (CO, USA) Vincent Di Stefano (VIC, Australia) Ian Drysdale (London, UK) Jorge Esteves (Oxford, UK) David Evans (Birmingham, UK) Ryan Everitt (NSW, Australia) Paula Fletcher (Kent, UK) Nadine Foster (Staffordshire, UK) Christian Fossum (Kent, UK) Gary Fryer (VIC, Australia) Grégoire Lason (Gent, Belgium) Eyal Lederman (London, UK) John Licciardone (TX, USA) Torsten Liem (Hamburg, Germany) Brad McCutcheon (Ontario, Canada) Christopher McGrath (Dunedin, New Zealand) John McPartland (VT, USA) Massimo Musicco (MiIan, Italy) Kate Nash (Ottawa, Canada) Elizabeth Niven (Auckland, New Zealand) Nicholas Penney (QLD, Australia) Graham Sanders (QLD, Australia) Florian Schwerla (Gating, Germany) Peter Sommerfeld (Korneuburg, Austria) Clive Standen (Auckland, New Zealand) Andrew Stewart (Auckland, New Zealand) Philip Tehan (VIC, Australia) Martin Underwood (Warwick, UK) Brett Vaughan (VIC, Australia) Nick Walters (London, UK) Heather Wheat (VIC, Australia) Frank Willard (ME, USA)

Official journal of the Australian Osteopathic Association, the General Osteopathic Council (UK) and the Ontario Association of Osteopaths, and recognised by the British Osteopathic Association. Amsterdam • Boston • London • New York • Oxford • Paris • Philadelphia • San Diego • St Louis

International Journal of Osteopathic Medicine 14 (2011) 1–2

Contents lists available at ScienceDirect

International Journal of Osteopathic Medicine journal homepage: www.elsevier.com/ijos

Editorial

Bringing fresh perspective to muscle energy technique

Seven years ago, we wrote an editorial called “The Seven Year Itch”. Another seven years later and our message is the same: the profession of osteopathy and the patients it serves would benefit from a greater understanding of how to provide accurate diagnoses more of the time, and how to implement treatment that is as efficacious as possible. While keeping that goal in mind the journal also continues to publish a wide variety of papers and the contents of this issue are a typical example of the broad interests present within the readership.

experience. Those familiar with the literature will know that studies have shown palpation of the CRI to be unreliable, and this study, while not a study of diagnostic reliability, reports that each group tended to record a different CRI rate. For those readers who employ treatment based on OCF concepts, this paper will be of interest for its redefining of normative rate. For those readers who prefer their palpatory phenomenon served up with a basis of objective measurement the paper is unlikely to move them any closer towards acceptance of the model.

Masterclass – an evidence informed update on muscle energy technique

Helical tensegrity and the geometry of anatomy

Fryer’s masterclass on muscle energy technique in this edition is a great example of the profession organising itself and its knowledge base. While it is difficult to change the everyday behaviour of practising osteopaths, it is (perhaps) an easier task to help them understand how current knowledge does, or does not, support that behaviour. We are fortunate to have members of the profession who are dedicated to synthesising the current knowledge for us and providing us with interpretation. In his article, which we highly recommend that you read, Fryer provides a straightforward summary of ‘evidence informed practice’ - a concept that we believe many readers will appreciate as it strikes a balance between what is possible and what is practical. He then applies his description of evidence informed practice to the topic of muscle energy technique. While this paper only reflects a snapshot of the detailed information that applies to this area, it is sufficiently deep to quickly bring you up to date. The paper also includes a few direct challenges to the status quo for anyone involved in teaching MET and we hope readers will enjoy the absence of the familiar dogma often associated with MET teaching texts and the freshness of statements such as “Sacroiliac dysfunctions proposed by Mitchell are clinical constructs, rather than definitive clinical entities” or “Practitioners should not assume every asymmetrical pelvis is dysfunctional and warrants treatment”. A revised look at normative rate in OCF.more fuel for the debate? We also publish the findings of a study investigating the rate of the cranial rhythmic impulse. Sergueef and colleagues performed a retrospective review of 734 study participants, examined by practitioners with different levels of experience. The results are presented in terms of the palpated rate of the CRI reported by the examiners in three groups, being 1, 2, or 3 to 25-years of 1746-0689/$ – see front matter Ó 2011 Published by Elsevier Ltd. doi:10.1016/j.ijosm.2011.02.001

Also in this issue is a critical review of helical tensegrity as it relates to human anatomy by Scarr. ‘Tensegrity’ (a portmanteau of ‘tension-integrity’) seems to be attracting growing interest amongst authors from the manual therapy and bodywork disciplines interested in the structural biology of connective tissues – particularly those investigating the biological and clinical significance of fascia. Tensegrity has also been mentioned in various osteopathic texts and may provide a useful approach to viewing the musculoskeletal system other than classical Newtonian mechanics. Scarr reviews the structural mechanism of tensegrity as a potential explanation for the integration of anatomy from the molecular level to the whole body. In this detailed review, Scarr highlights many examples of anatomical structures that contain helical patterns. Photographs of Scarr’s elegant handmade models illustrate the text and readers should access the online version of this paper to fully appreciate the elegance of the models. Studying the effectiveness of strategies to encourage a rural workforce in the health professions Workforce planning for osteopathy in the UK, Australia and NZ continues to be of interest to the professional bodies and regulatory authorities and there has been some concern and anecdotal reporting about difficulties encouraging new graduates to consider moving outside of the major metropolitan areas where they trained. It’s quite common to hear of rural and provincial practitioners reporting of difficulties attracting associates despite good remuneration and working conditions. Of course, this problem is not unique to osteopathy and the same issues are also common to a range of health professions internationally. In the United States there is a well-documented shortage of physicians working in rural areas, particularly in family medicine and primary care. Many osteopathic medical schools in the United States aim to produce

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Editorial / International Journal of Osteopathic Medicine 14 (2011) 1–2

graduates who will work in rural areas and use a range of strategies to meet this aim. In this issue, we publish a paper by Whitacre and colleagues that explores the effectiveness of some of these strategies in influencing the practice location of graduates. Although the paper will be of most direct interest to those involved in health provision in the United States, their method provides a useful approach to investigating this problem that could be employed in any country.

Nicholas Lucas Sydney, Australia E-mail address: [email protected] (N. Lucas) Robert Moran Department of Osteopathy, Unitec Institute of Technology, Auckland, New Zealand E-mail address: [email protected] (R. Moran)

International Journal of Osteopathic Medicine 14 (2011) 3e9



Masterclass

Muscle energy technique: An evidence-informed approach Gary Fryer a, b, * a b

School of Biomedical & Health Sciences; ISEAL, Victoria University, Melbourne, Australia A.T. Still Research Institute, A.T. Still University of Health Sciences, Kirksville, MO, USA

a r t i c l e i n f o

s u m m a r y

Article history: Received 16 February 2010 Received in revised form 30 March 2010 Accepted 9 April 2010

This article describes the principles of evidence-based medicine and how these principles may be implemented in osteopathic practice and applied to the use of muscle energy technique. Because the feasibility of strict adherence to ‘evidence-based’ principles is debated, an approach of ‘evidenceinformed practice’ is recommended. The principles and diagnostic and treatment practices associated with muscle energy technique are re-examined in light of recent research. Implications for the application of muscle energy are outlined, and recommendations are made regarding clinical practice. Ó 2010 Elsevier Ltd. All rights reserved.

Keywords: Muscle energy technique Isometric Manipulation Evidence-based medicine Osteopathic medicine

1. Introduction Muscle energy technique was developed by osteopathic physician, Fred Mitchell, Sr. It was refined and systematised by Fred Mitchell, Jr., and has continued to evolve with contributions from many individuals. Muscle energy technique (MET) is used by practitioners from different professions and has been advocated for the treatment of shortened muscles, weakened muscles, restricted joints, and lymphatic drainage. In addition to using muscle effort to mobilise joints and tissues, MET is considered by some to be a biomechanics-based analytic diagnostic system that uses precise physical diagnosis evaluation procedures to identify and qualify articular range of motion restriction.1 Recent research suggests a revision of MET concepts and practices is required, particularly considering the trend towards evidence-based medicine (EBM). 2. Evidence-based medicine and evidence-informed practice Medical and allied health practitioners have been encouraged to practice according to the principles of EBM.2 However, some practitioners raise concern that EBM may be applied for economic reasons rather than best care.3,4 Others argue that EBM does not account for other kinds of medical knowledge5 and that EBM * Osteopathic Medicine Unit, School of Biomedical and Health Sciences, Victoria University, P.O. Box 14428 MCMC, Melbourne 8001, Australia. E-mail address: [email protected] 1746-0689/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijosm.2010.04.004

studies, primarily randomised controlled trials (RCTs), address average results from large groups instead of data applicable to individual patients.6 A treatment effective for the majority may not always be effective for an individual for a variety of reasons, including the aetiology of their condition, past experience (negative or positive), and expectations of treatment outcome. Some approaches may be more effective in the hands of particular practitioners because of skill and experience. Certain treatments may also have larger non-specific (placebo) effects, and these effects should not be dismissed. The adoption of ‘best’ evidence may unintentionally limit practice, so balance between external clinical evidence and clinical experience is necessary. In manual therapy, strict adherence to EBM is not possible due to a lack of high-quality evidence on which to base decisions. EBM was originally intended to integrate clinical expertise with the best available clinical evidence,10 but many have argued that a narrow interpretation of EBM is prevalent, where treatment must be based on high-quality evidence and the role of clinical experience is devalued.3e6 Given that many professions are not able to base treatment on evidence, it has been argued that a preferred terminology is ‘evidence-informed practice’7 or ‘evidence-informed osteopathy’,8,9 which more accurately reflects the realty of the use of evidence in osteopathic practice. Evidence-informed practice has been defined as the process of integrating research evidence when available but including personal recommendations based on clinical experience, while retaining transparency about the process used to reach clinical decisions.7

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G. Fryer / International Journal of Osteopathic Medicine 14 (2011) 3e9

2.1. Implementing evidence-informed principles into osteopathic practice Given the paucity of high-quality research evidence related to osteopathic practice, it can be difficult to see how implementing EBM principles may make a difference to practice. However, adopting practices consistent with evidence-informed practice e using evidence when available to guide decision making e may shift the practice culture to improve patient care. While Strauss11 described 5 steps of EBM (asking a question, finding the evidence, applying information in combination with clinical experience and patient values, and evaluating the outcomes), a practitioner must start this approach with a ‘spirit of inquiry’.12 2.1.1. Spirit of inquiry Osteopaths should have a spirit of inquiry,12 a curiosity about the best evidence to guide clinical decision making. If a practitioner believes they already know everything or that clinical secrets can only be obtained from esoteric experiential practices, that modern research has nothing to offer, then the practitioner is unlikely to embrace evidence-informed practice. Willingness to change when there is good reason to do so is important for clinicians as well as the profession. 2.1.2. Search for evidence Keeping informed can be daunting for those unaccustomed to searching electronic databases and reading papers. For osteopaths, subscriptions to relevant journals (membership of many professional associations provides electronic access to osteopathic and manual therapy journals) are a place to start. Practitioners should regularly sight journal contents, skim the abstracts of interesting articles, and read further if there is relevance to clinical practice. Many osteopathic and manual therapy journals provide evidence summaries, comment on clinical guidelines, and review articles, which may offer evidence to guide decision making. Practitioners should ask questions and research patient problems. When presented with a new or a difficult problem, practitioners should spend time researching the problem. In addition to consulting textbooks, practitioners are also able to access information using the free PubMed service or Google Scholar, which have links to primary research articles or other clinical information. When searching electronic databases, the PICOT (population, intervention, comparison, outcome, timeframe) approach is useful for identifying keywords and phrases.11,13 Osteopaths should develop a culture of seeking knowledge, looking at every patient encounter as a challenge to learn more. 2.1.3. Integrate evidence with clinical experience Critical appraisal of research involves determining if the results are valid, if they are important, and if they will improve patient care. Critical appraisal may initially be difficult for those unfamiliar with this approach, and osteopaths are encouraged to participate in journal clubs to discuss articles and learn about the process of article critique. Evidence-informed practice involves assessing the relevance of existing evidence with the needs of the patient and integrating this knowledge with our own experience, other forms of evidence (expert opinion, physiological rationale, etc.), and the patient’s expectations and needs during treatment. In short, evidenceinformed practice uses evidence to make informed decisions and guide treatment for the benefit of patients. Working within evidence-based guidelines, treatments should be consistent with current research, but the flexibility to use treatments according to the judgement of the clinician (based on previous experience, awareness of patient values or preferences) should be utilized.

Practitioners may use research evidence and clinical guidelines to add techniques to what they use for best patient care, rather than removing treatments with anecdotal or theoretical rationale, but this will depend on the available evidence relevant to the patient presentation. 2.1.4. Evaluate outcomes By evaluating the effect of a change in practice approach, an osteopath can assess whether the change has been beneficial. This may be difficult to determine because of the heterogeneity of patients and their complaints, however, if standard outcome measures are used (validated self-reported questionnaires, visual analogue pain scales, the Oswestry Disability index, Neck Disability index, etc.) then evaluation becomes more objective.

3. Evidence-informed approach to muscle energy Like many manual therapeutic approaches, the efficacy and effectiveness of MET technique are under-researched, and there is little evidence to guide practitioners in the choice of the most useful technique variations (such as number of repetitions, strength of contraction, duration of stretch phase), causing frustration for those endeavouring to integrate relevant evidence into practice. A limited but growing number of studies show positive change following MET intervention. Studies that demonstrate an increase in the extensibility of muscles14e19 and spinal range of motion20e24 support the rationale of treating patients with reduced mobility, although research involving clinical outcomes is scarce. One case study series25 and one RCT26 for the treatment of acute low back pain (LBP) are the only English language studies that examined MET as the sole treatment using clinical outcomes. Both reported decreased pain following treatment. The lack of clinically relevant research is not surprising given that MET is typically used in conjunction with other techniques. Several clinical trials investigating osteopathic management of spinal pain have included MET as a treatment component, and given that treatment significantly reduced the reported pain and disability in these trials, they provide further support for the effectiveness of muscle energy, at least as part of a treatment package.27e29 While there is need for further investigation of muscle energy, available evidence supports the use of this approach to treat restricted mobility and spinal pain. Although limited evidence exists for the efficacy of muscle energy, the current research literature indicates a need to reconsider the clinical diagnostic methods and the physiological mechanisms causing therapeutic effect. The mechanisms underlying the possible therapeutic effects are largely speculative, but evidence supports the plausibility of several modes of action. An understanding of the likely mode of action may inform and influence the application of muscle energy.

3.1. Diagnostic concepts Drs. Mitchell, Sr. and Jr., integrated clinical and anatomical observations and developed their approach based on Fryette’s physiological spinal coupling concept30 and a pelvic biomechanical model developed in conjunction with Paul Kimberley.1 Their approach has been adopted by most North American authors of MET texts1,31e35 although authors elsewhere have not always linked the technique to these models.36 Recent evidence casts doubt on the predictability of spinal coupled motion and raises questions about the validity and reproducibility of many of the recommended diagnostic tests.


3.1.1. Assessment of the spine The traditional paradigm for diagnosis and treatment is mechanical, where multiple planes of motion loss are determined and each restrictive barrier is engaged to increase motion in all restricted planes.1,31e35 The identification of motion restriction has been based on the spinal coupled motion model proposed by Fryette,30 which describes two types of coupled motion restriction: Type 1 (rotation and sidebending to opposite sides) is based on spinal asymmetry detected in neutral postures, while Type 2 (rotation and sidebending to the same side) is based on asymmetry in non-neutral spinal postures. Fryette’s model has been criticized for its prescriptive diagnostic labelling and dubious inferences from static positional assessment.37,38 Further, it allows only three combinations of multiple plane motion restrictions: a neutral Type 1, a non-neutral Type 2 with flexion, or a non-neutral Type 2 with extension. The model does not allow for other combinations, such as rotation and sidebending to opposite sides with extension, and techniques for these combinations of motion restriction are not found in texts. Osteopathic texts advocate detection of dysfunctional spinal segments by using the diagnostic criteria of segmental tenderness, asymmetry, restricted range of motion, and altered tissue texture.1,31e33,39,40 The validity, reliability, and specificity of these criteria have been questioned,41e43 given only palpation for tenderness and pain provocation has acceptable interexaminer reliability. Using a combination of criteria (as suggested by osteopathic texts) that include tenderness or pain may improve the reliability of osteopathic examination. MET texts commonly suggest the assessment of static positional asymmetry of the spinal transverse process or sacral base with the spine in neutral, flexion, and extension. Implicit to this approach is an assumption that a transverse process posterior or resistant to posterioreanterior springing represents a restriction of rotation to the opposite side, and inferences about coupled sidebending are made according the spinal posture. Although muscle asymmetry and anatomical vertebral asymmetry are complicating factors, they are not considered. Additionally, assessment of segmental static asymmetry has been shown to be unreliable,44 and spinal coupled motion in the lumbar, thoracic, and cervical spine is inconsistent between spinal levels and individuals.38,45e50 Coupled motion in the upper cervical region is relatively consistent,51 but inconsistencies in the lumbar and thoracic regions invalidate the Fryette model when predicting triplanar motion restrictions based on static asymmetry or single plane motion restriction, as recommended in many texts.1,31e35 3.1.2. Assessment of the pelvis Sacroiliac motions are small and complex, involving simultaneous rotation and translation.52,53 The sacroiliac joint has no primary motion but acts passively to accommodate torsional stress during ambulation,52 and the axes of motion are dependent upon the surface topography of the joints, which vary between individuals. Mitchell and others1,31e35 advocate sacroiliac motion testing during standing and seated flexion to determine landmark asymmetry and the type of dysfunction, however, the usefulness of these tests is not supported by the literature.54e57 Forward flexion tests have poor reliability and lack construct validity.58e60 The reliability of pelvic landmark asymmetry is poor,60e63 unless substantial asymmetry exists.64 Clusters of sacroiliac tests, mainly pain provocation, appear to have clinical utility,54,55,57 but are generally not recommended by MET texts, having utility for detecting a symptomatic joint, rather than sacroiliac dysfunction. The construct validity of pelvic asymmetry as an indicator of dysfunction is also lacking, but some evidence suggests asymmetry may have functional implications.65,66 Although pelvic torsion

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appears unrelated to LBP or positive clinical tests,67,68 subtle pelvic torsion may create an asymmetrical load on the lumbar and thoracic tissues.65,66 Sacroiliac motion in healthy volunteers is typically symmetrical, and asymmetrical motion (hypermobility rather than restricted motion) may be predictive for pelvic pain.69e72 Sacroiliac dysfunctions proposed by Mitchell are clinical constructs, rather than definitive clinical entities. The absence of objective indicators of mechanical dysfunction of the sacroiliac joint and poor reliability of the motion tests used to detect it make sacroiliac dysfunction difficult to validate. Nevertheless, variability of sacroiliac anatomy and motion may cause the described dysfunctions in susceptible individuals. Pelvic asymmetry, however, may be secondary to myofascial imbalance. One study73 found electrical activation of the pelvic floor muscles produced a large effect on pelvic alignment. MET techniques involve contraction and stretch of myofascial structures and if muscle imbalance and altered tone has a role in producing pelvic asymmetry, it is possible that MET may influence pelvic alignment and functional symmetry by affecting myofascial tissues, rather than directly affecting the sacroiliac joint. 3.1.3. Implications for assessment in clinical practice With dubious reliability and validity for many tests of spinal and pelvic dysfunction, practitioners following an evidence-informed approach will be frustrated. Until we have tests with better clinical usefulness, the practitioner should use those tests with face validity and clinical utility based on experience, be cautious about making firm conclusions based on single clinical findings, and use a variety of tests that support a logical clinical reasoning process. Due to the unpredictability of coupled motions in the spine, practitioners should address motion restrictions that present on palpation (despite issues of reliability), rather than assumptions based on biomechanical models and static palpatory findings. If corrective motion is introduced in the primary planes of restriction, spinal coupling (in whatever direction) will occur automatically e due to the nature of conjunct motion ewithout being intentionally introduced by the practitioner. Therefore, the pragmatic approach addresses the primary motion restriction(s); coupled motion will occur without the aid of the practitioner. Despite the shortcomings of many of the pelvic and sacroiliac assessment methods, a pragmatic approach uses a cluster of tests, incorporating motion and provocative testing, not relying on a single isolated finding. Practitioners should not assume every asymmetrical pelvis is dysfunctional and warrants treatment. For flexion tests, a difference between standing and seated observations may be significant, but indicating asymmetry in the pelvis and/or lower extremity, rather than sacroiliac dysfunction. Practitioners should consider that pelvic asymmetry may be caused by myofascial imbalance (asymmetry of length, strength or activation pattern) articular dysfunction, and attention should be given to assessment and treatment of these tissues. 3.2. Therapeutic mechanisms The proposed mechanisms underlying the possible therapeutic effects of MET have been largely speculative. Research examining the physiological mechanisms of MET is ongoing, however the current evidence challenges some of the proposed therapeutic concepts. The underlying therapeutic action may involve a variety of neurological and biomechanical mechanisms, including hypoalgesia, altered proprioception, motor programming and control, and changes in tissue fluid.75e77 MET may also have physiological effects regardless of presence or absence of dysfunction.22,23 An understanding of the likely physiological therapeutic mechanisms

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underlying manual techniques may assist an evidence-informed approach for technique selection. Reflex muscle relaxation is commonly cited as a mechanism for length, range of motion (ROM), and tissue texture changes following muscle energy.1,31,36,78 However, studies support increased tolerance to stretching (hypoalgesia), not reflex relaxation, as the mechanism for increasing muscle extensibility.14,16,76,79 Although reflex relaxation appears plausible from studies examining muscle contraction with electrophysiological parameters,80e82 no study has shown a decrease in electromyographic (EMG) activity following muscle energy. On the contrary, MET and similar techniques have increased the low-level EMG activity during and following stretching, despite an increase in muscle length.16,17,83,84 Evidence of EMG disturbance in the paraspinal muscles of patients with LBP exists,85,86 but no study has investigated MET and EMG activity in the spine. Thus, factors other than reflex muscle relaxation seem responsible for muscle extensibility and ROM following these techniques. Applications of MET to stretch and increase myofascial tissue extensibility seem to affect viscoelastic and plastic tissue property,87,88 autonomic-mediated change in extracellular fluid dynamics,89 and fibroblast mechanotransduction,89,90 but few lasting changes in human muscle properties have been found.76 Studies measuring pre- and post-force (torque) show little viscoelastic change after passive or isometric stretching and indicate that muscle extensibility is due to increased tolerance to an increased stretching force.14,16,79 Although short- and medium-term application of stretching and MET may alter the perception of pain, it does not appear to affect the biomechanics of healthy muscle, but studies are required for injured and healing muscle tissue. MET may influence pain mechanisms and promote hypoalgesia. Studies suggest MET and related post-isometric techniques reduce pain and discomfort when applied to the spine26 or muscles.14,16 The mechanisms are not known, but may involve central and peripheral modulatory mechanisms, such as activation of muscle and joint mechanoreceptors that involve centrally mediated pathways, like the periaqueductal grey (PAG) in the midbrain, or nonopioid serotonergic and noradrenergic descending inhibitory pathways. Animal and human studies have shown sympathoexcitation and localised activation of the lateral and dorsolateral PAG from induced or voluntary muscle contraction,91,92 and activation of non-opioid descending inhibitory pathways from peripheral joint mobilization.93,94 Additionally, MET may increase fluid drainage and augment hypoalgesia. Rhythmic muscle contraction increases muscle blood and lymph flow rates,95 and mechanical forces acting on fibroblasts in connective tissues change interstitial pressure and increase transcapillary blood flow.96 MET application may reduce pro-inflammatory cytokines and desensitize peripheral nociceptors. MET may also produce changes in proprioception, motor programming, and control. Spinal pain disturbs proprioception and motor control, causing decreased awareness of spinal motion and position97e101 and cutaneous touch perception.102,103 Spinal pain affects motor programming, inhibiting the stabilizing paraspinal musculature, while causing superficial spinal muscles to overreact to stimuli.85,86 No study has investigated the effect of MET on proprioception or motor control, but limited evidence suggests benefit from other manipulative treatments.104e108 Since MET produces joint motion while actively recruiting muscles, it may affect proprioceptive feedback, motor control, and motor learning; this should be investigated in the future. Authors of MET texts have proposed that the technique improves lymphatic flow and reduces edema,1,109 and evidence from muscle contraction and physical activity studies support this.95,98,110,111 Muscle contraction increases interstitial tissue fluid

collection and lymphatic flow,95,111 and physical activity increases lymph flow peripherally in the collecting ducts, centrally in the thoracic duct, and within the muscle during concentric and isometric muscle contraction.98,110 MET may assist lymphatic flow and clearance of excess tissue fluid to augment hypoalgesia, changing intramuscular pressure and the passive tone of the tissue. The mechanisms outlined above may explain some of the therapeutic action of MET technique, but are not likely to be specific to this technique and will possibly be activated by any physical activity that produces muscle contraction. It is argued that MET applied specifically to a painful and dysfunctional region may produce local changes in circulation, inflammation and proprioception, and although these proposed mechanisms appear plausible they are still largely speculative. The relative efficacy of specifically applied MET compared to general physical activity has not been explored and would help to determine the usefulness of MET for regional pain and dysfunction. 4. Evidence-informed application of muscle energy The implications of the current research literature are more pertinent for theoretical concepts of MET than to its use in clinical practice. As discussed previously, MET may be useful for increasing muscle extensibility and spinal range of motion and for low back and neck pain. However, clinicians should be circumspect about the structural diagnosis process and not rely on isolated diagnostic tests and findings. While studies have examined the efficacy of technique variations,23,112,113 few recommendations can be made. The mechanisms underlying MET are uncertain and based on inference from related studies, but some appear plausible, allowing speculation on their clinical implications. Consistent with an evidence-informed approach, these inferences from research should be balanced with clinical experience. 4.1. Muscle energy for increasing muscle length Evidence suggests MET (or similar isometric stretching techniques) is more effective than passive stretching for increasing muscle extensibility. Due to lack of studies or conflicting evidence, little information exists about the optimal number of isometric contractions, the duration and intensity of contraction, or the force of the stretch.76 Evidence for the most effective direction of contraction to increase flexibility in healthy muscle does exist. To gain maximum ROM and muscle extensibility, the use of isometric variations that include recruitment of the agonist muscle is suggested. Agonistcontract (AC) and contract-relax agonist-contract (CRAC) are variants of proprioceptive neuromuscular facilitation, where the patient actively pushes further into the barrier (AC) or where isometric contractions away from and into the barrier are alternated. These techniques have been consistently effective for increasing flexibility76 but are appropriate where muscles are not painful. It is not recommended for muscles or joints that are painful because pushing into the painful barrier would likely produce protective muscle guarding and apprehension. The duration of the stretch phase for maximum gains in flexibility should be considered. Many recommend only a few seconds of relaxation before re-engaging the new barrier,1,31e35 but Chaitow recommends a duration of up to 60 s for chronically shortened muscles.36 Studies reporting that duration of stretch influences the amount and longevity of ROM gains support this recommendation.114e117 Further, longer stretching durations are more effective than short durations, with 15 s more effective than 5114 and 30 s more effective than 15 but no different than 60.115,116 Feland et al.117 reported a 60-s stretch produced greater gains in


ROM that lasted longer than lesser durations for elderly people with tight hamstrings, and their subjects may be representative of those with chronically shortened fibrotic muscles. Although no studies suggest the best application for stretching painful muscles, healing muscles, or active trigger points, gentle contraction and stretching forces with shorter durations should be used to recruit sensitised fibres (as suggested for myofascial trigger points), avoid further tissue damage, and promote repair and healing. An evidence-informed approach for painless, chronic, fibrotic muscles indicates moderate contraction and stretching forces, maintain the stretch phase up to 60 seconds, and use AC or CRAC where appropriate. 4.2. Muscle energy for spinal dysfunction The unpredictability of coupled motions in the thoracic and lumbar spine has been discussed, and practitioners should address motion restrictions that present on palpation in as many planes as identified. If motion is introduced in the primary plane(s) of restriction, coupled motion will occur automatically. If multiple plane motion restrictions are identified that do not conform to the Fryette model, technique should be adapted to accommodate the motion restrictions identified. If segments do not respond to treatment, then the diagnosis should be reassessed and clinical judgement used regarding appropriate further treatment. The chronicity of spinal dysfunction may influence the choice of technique and approach. The aetiology of segmental dysfunction is speculative, but acute dysfunction may arise from minor trauma, producing minor strain and inflammation in the spinal unit. In acute spinal conditions, zygapophysial joint sprain and effusion may produce local pain and limited motion (active and passive). Following strain and inflammation, nociceptive pathways may be activated and initiate a cascade of events, including the release of neuropeptides from involved nociceptors that promote tissue inflammation. This neurogenic inflammation may outlast the tissue damage and contribute to tissue texture abnormality. Additionally, central nervous system motor strategies may be altered to inhibit deep paraspinal muscles and produce excitation of more superficial muscles, which may further altering tissue texture and quality of motion.74,77 With acute dysfunction, techniques should promote fluid drainage, hypoalgesia, and proprioceptive input. MET should be applied to the ‘first’ barrier (first sense of increasing resistance to motion) as described by Mitchell,1 with repeated gentle isometric contractions. Repetitive mid-range articulation may assist transsynovial flow and lymphatic drainage, and indirect techniques (techniques that place the joint or tissues in a position of ease or relaxation) may have a role in reducing the secretion of proinflammatory peptides to minimise pain and inflammation.118 Chronic dysfunction is characterised by restricted range of motion, thickened tissues, and relatively little localised pain or tenderness at the site of dysfunction. Following acute injury (and probably ongoing repetitive trauma due to deficiencies in proprioception, motor control, and stabilisation), degenerative changes occur in the intervertebral disc and zygapophysial facet joints, periarticular connective tissue undergoes proliferation and shortening, and these degenerative changes act as co-morbid conditions that continue to affect the spinal unit. Sensitised nociceptive pathways may interfere with proprioceptive processing, creating deficits in proprioception and affecting segmental muscle control, which may disrupt the dynamic stability of the segment and predispose it to ongoing mechanical strain.74,77 For segmental dysfunctions that suggest a chronic condition, the most beneficial techniques may be those that stretch and mobilise tissues and improve proprioception and motor control. When

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applying MET to a chronic and restricted joint, engaging the barrier at the point of elastic end-range (rather than the first barrier) will load and stretch the shortened capsule and peri-capsular structures to produce viscoelastic and possibly plastic changes. Provided the localisation is maintained, more moderate contraction forces can be used to enhance post-isometric hypoalgesia and stretch tolerance and allow adequate post-contraction loading on the tissues. Isometric contraction will help proprioceptive feedback and recruitment, but controlled isotonic (eccentric) contraction e allowing the muscle to shorten over the range of motion e may also be beneficial. High-velocity, low-amplitude (HVLA) thrust technique might be used with end-range articulation, given HVLA creates cavitation and increases joint separation in the short-term, allowing end-range articulation to optimally stretch the pericapsular tissues. 4.3. Muscle energy for pelvic dysfunction As discussed, many diagnostic tests have dubious value, and a pragmatic approach uses a cluster of tests, incorporating motion and provocative testing, and does not rely on a single isolated finding. Pelvic asymmetry may be caused by myofascial imbalance (asymmetry of length, strength or activation pattern) rather than articular dysfunction, and attention should be given to treatment of these tissues. Osteopaths have emphasised sacroiliac dysfunction as a hypomobility lesion, but should also consider hypermobility as an aetiology for the painful joint,119 considering that asymmetrical joint laxity is associated with pelvic pain in pregnant women.69e72 In addition to improving perceived pelvic symmetry and function, MET may enhance motor recruitment and stability by using isotonic (eccentric) contraction to improve motor recruitment for pelvic and hip muscle weakness and atrophy.1 The addition of motor control and stability training for these patients should be considered.120 5. Conclusion Evidence-informed practice uses research evidence when available, followed by personal recommendations based on clinical experience, while retaining transparency about the process used to reach clinical decisions. There is a lack of high-quality research regarding the efficacy and effectiveness of MET, as well as the therapeutic mechanisms, but emerging evidence supports the clinical usefulness of this technique. However, reassessment of the recommended assessment practices associated with the technique is required, and additional evidence should establish plausible therapeutic mechanisms to guide therapeutic decisions about application of the technique for different conditions. Acknowledgements The author wishes to thank Deborah Goggin, MA, Scientific Writer, A.T. Still Research Institute, A.T. Still University, for reviewing this manuscript. This manuscript was based, in part, on a previous article published in Franke H., ed. Muscle Energy Technique: HistoryeModeleResearch (Monograph). Ammersestr: Jolandos; 2009:57e62.75 Statement of competing interests Gary Fryer is a member of the Editorial Board of the Int J Osteopath Med but was not involved in review or editorial decisions regarding this manuscript.

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References 1. Mitchell Jr FL, Mitchell PKG. The MET manual, vol. 1. East Lansing, Michigan: MET Press; 1995. 2. Oxman AD, Lavis JN, Fretheim A. Use of evidence in WHO recommendations. Lancet 2007;369:1883e9. 3. Porta M. Is there life after evidence-based medicine? J Eval Clin Pract 2004;10:147e52. 4. Rosenfeld JA. The view of evidence-based medicine from the trenches: liberating or authoritarian? J Eval Clin Pract 2004;10:153e5. 5. Tonelli MR. Integrating evidence into clinical practice: an alternative to evidence-based approaches. J Eval Clin Pract 2006;12:248e56. 6. Bluhm R. From hierarchy to network: a richer view of evidence for evidencebased medicine. Perspect Biol Med 2005;48:535e47. 7. Haldeman S, Dagenais S. What have we learned about the evidence-informed management of chronic low back pain? Spine J 2008;8:266e77. 8. Green J. Evidence-based medicine or evidence-informed osteopathy? Osteopath Today; April 21e22, 2000. 9. Fryer G. Teaching critical thinking in osteopathy e integrating craft, knowledge and evidence-informed approaches. Int J Osteopath Med 2008;11:56e61. 10. Sackett DL, Rosenberg WM, Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn’t. Br Med J 1996;312:71e2. 11. Strauss SE, Richardson WS, Glasziou P, HRB. Evidence-based medicine: how to practice and teach EBM. 3rd ed. Edinburgh: Elsevier, Churchill Livingstone; 2005. 12. Melnyk BM, Fineout-Overholt E, Stillwell SB, Williamson KM. Evidence-based practice: step by step: igniting a spirit of inquiry: an essential foundation for evidence-based practice. Am J Nurs 2009;109:49e52. 13. Melnyk BM, Fineout-Overholt E, Stillwell SB, Williamson KM. Evidence-based practice: step by step: the seven steps of evidence-based practice. Am J Nurs 2010;110:51e3. 14. Ballantyne F, Fryer G, McLaughlin P. The effect of MET technique on hamstring extensibility: the mechanism of altered flexibility. J Osteopath Med 2003;6:59e63. 15. Ferber R, Gravelle DC, Osternig LR. Effect of proprioceptive neuromuscular facilitation stretch techniques on trained and untrained older adults. J Aging Phys Act 2002;10:132e42. 16. Magnusson SP, Simonsen EB, Aagaard P, Dyhre-Poulsen P, McHugh MP, Kjaer M. Mechanical and physiological responses to stretching with and without preisometric contraction in human skeletal muscle. Arch Phys Med Rehabil 1996;77:373e7. 17. Osternig LR, Robertson RN, Troxel RK, Hansen P. Differential responses to proprioceptive neuromuscular facilitation (PNF) stretch techniques. Med Sci Sports Exerc 1990;22:106e11. 18. Sady SP, Wortman M, Blanke D. Flexibility training: ballistic, static or proprioceptive neuromuscular facilitation? Arch Phys Med Rehabil 1982; 63:261e3. 19. Wallin D, Ekblam B, Grahn R, Nordenborg T. Improvement of muscle flexibility. A comparison between two techniques. Am J Sports Med 1985; 13:263e8. 20. Schenk RJ, Adelman K, Rousselle J. The effects of MET technique on cervical range of motion. J Man Manipulative Ther 1994;2:149e55. 21. Schenk RJ, MacDiarmid, Rousselle J. The effects of MET technique on lumbar range of motion. J Man Manipulative Ther 1997;5:179e83. 22. Lenehan KL, Fryer G, McLaughlin P. The effect of MET technique on gross trunk range of motion. J Osteopath Med 2003;6:13e8. 23. Fryer G, Ruszkowski W. The influence of contraction duration in MET technique applied to the atlanto-axial joint. J Osteopath Med 2004;7:79e84. 24. Burns DK, Wells MR. Gross range of motion in the cervical spine: the effects of osteopathic met technique in asymptomatic subjects. J Am Osteopath Assoc 2006;106:137e42. 25. Lamberth L, Hansen KL, Bloch-Thomsen M, Silbye P, Remvig L. MET technique: a useful aid to manual treatment of low back pain? J Orthop Med 2005; 27:17e21. 26. Wilson E, Payton O, Donegan-Shoaf L, Dec K. MET technique in patients with acute low back pain: a pilot clinical trial. J Orthop Sports Phys Ther 2003; 33:502e12. 27. Licciardone JC, Stoll ST, Fulda KG, et al. Osteopathic manipulative treatment for chronic low back pain: a randomized controlled trial. Spine 2003; 28:1355e62. 28. Fryer G, Alivizatos J, Lamaro J. The effect of osteopathic treatment on people with chronic and sub-chronic neck pain: a pilot study. Int J Osteopath Med 2005;8:41e8. 29. Chown M, Whittamore L, Rush M, Allan S, Stott D, Archer M. A prospective study of patients with chronic back pain randomised to group exercise, physiotherapy or osteopathy. Physiotherapy 2008;94:21e8. 30. Fryette HH. Principles of osteopathic technic. Newark, OH: American Academy of Osteopathy; 1954. 31. Greenman PE. Principles of manual medicine. 3rd ed. Philadelphia: Lippincott William & Wilkins; 2003. 32. DiGiovanna EL, Schiowitz S, Dowling DJ. An osteopathic approach to diagnosis & treatment. 3rd ed. Philadelphia: Lippincott William & Wilkins; 2005. 33. Ehrenfeuchter WC, Sandhouse M. MET techniques. In: Ward RC, editor. Foundations for osteopathic medicine. 2nd ed. Philadelphia: Lippincott William & Wilkins; 2003. p. 881e907.

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International Journal of Osteopathic Medicine 14 (2011) 10e16



Research report

The palpated cranial rhythmic impulse (CRI): Its normative rate and examiner experience Nicette Sergueef, Melissa A. Greer, Kenneth E. Nelson*, Thomas Glonek Department of Osteopathic Manipulative Medicine, Chicago College of Osteopathic Medicine, Midwestern University, 555 31st Street, Downers Grove, IL 60515, USA

a r t i c l e i n f o

a b s t r a c t

Article history: Received 10 March 2009 Received in revised form 12 November 2009 Accepted 25 November 2010

This retrospective review study aims to contribute data regarding the normal range of the palpated cranial rhythmic impulse (CRI) rate from a population of 734 healthy subjects, each determined by a different examiner. Experience levels ranged from 1 to 25 years training/practice in cranial osteopathy. This study reports an overall CRI rate range (mean SD) of 6.88 4.45 cpm for all subjects (valid N ¼ 727). The examiner population was subdivided into three groups based upon the level of examiner experience. The rates obtained from each subgroup, from least experienced to most experienced, are as follows: Level 1 (one year of experience), 7.39 4.70; Level 2 (two years of experience), 6.46 4.10; Level 3 (three-twenty five years of experience), 4.78 2.57. Both group mean values of the reported palpated CRI rates and their standard deviations showed an inverse relationship with the level of examiner experience, i.e., as experience increases, the mean CRI rate and its deviation decreases. In the light of the findings of this study, the currently accepted range of the palpated CRI, 8e14 cycles/minute, should be reconsidered to be as low as 2e7 cycles/minute. Précis: CRI rate means and ranges as assessed by experienced examiners are, respectively, lower and narrower. Ó 2010 Elsevier Ltd. All rights reserved.

Keywords: Osteopathic Medicine Osteopathic Manipulative Medicine Osteopathy in the Cranial Field Cranial Osteopathy Medical education Teaching psychomotor skills Cranial rhythmic impulse CRI rate Primary Respiratory Mechanism

1. Introduction In the paradigm of cranial osteopathy, a controversial rhythmicity, the cranial rhythmic impulse (CRI), has been described, discussed, and debated.1e5 It is defined in the Glossary of Osteopathic Terminology6 as “a palpable rhythmic fluctuation believed to be synchronous with the primary respiratory mechanism.” The fact that the CRI is debatable and incompletely understood makes it subject to question and, therefore, of interest for corroboration of its normative parameters. In 1939, William G. Sutherland first proposed cranial osteopathy and, what he suggested was a means of holistically coordinating the approach to patient care, the primary respiratory mechanism (PRM).7 He described it as a biphasic phenomenon, independent of pulmonary respiration, with an “inspiratory” and an “expiratory” phase. It is interesting to note that nowhere in the early descriptions of the cyclic PRM is there specific mention of its rate or normative range. In fact, it wasn’t until 1961, well after Sutherland’s

* Corresponding author. Tel.: þ1 630 515 6039/1 630 515 7123 (OMM departmental office), fax: þ1 630 515 6949. E-mail addresses: [email protected] (N. Sergueef), melissa.greer@ mwumail.midwestern.edu (M.A. Greer), [email protected] (K.E. Nelson), [email protected] (T. Glonek). 1746-0689/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijosm.2010.11.006

death, that Woods and Woods first published the term cranial rhythmic impulse and a normative rate for it (10e14 cpm).8 The establishment of normative parameters for the rate of the CRI subsequently has been controversial due to: (1) the lack of an accepted objective approach, (2) the esoteric nature of the phenomenon, (3) the subjective nature of the CRI’s detection through palpation, (4) the relatively low number of researchers experimentally measuring the rate, and (5) the comparatively low subject population numbers in many of the published studies. Recognized osteopathic textbooks5,9,10 cite the rate in the range of 8e14 cpm, consistent with the original, 1961, Woods and Woods study.8 This range still is often cited as definitive even though a much lower range has been reported repeatedly.11e18 Past reported measured rates for the palpated rate of the CRI are presented for comparison in Table 1, along with the values from this study. The aims of this study were (1) to define the normative rate of the CRI and (2) to compare palpated CRI rates obtained by practitioners at three experience levels. 2. Methods The study was organized around the teaching activities of one of the authors (NS) in compliance with the legal requirements of the Commission Nationale de l’Informatique et des Libertés (CRIL) and

N. Sergueef et al. / International Journal of Osteopathic Medicine 14 (2011) 10e16 Table 1 Reported cranial rhythmic impulse (CRI) rate ranges. Authors

CRI Rate (Range or Values)

Subjects in Study (N)

Year Reported

Woods and Woods8 Norton et al.11 Wirth-Pattullo and Hayes12 McAdoo and Kuchera13 Hanten et al.14 Rogers et al.15 Sommerfeld16 Moran and Gibbons17 Nelson et al.18 This Study All subjects 1 year experience 2 years experience 3e25 years experience

10e14 3.2e4.1 3e9 6.63e9.37 3.6 & 4.2 3.28 & 4.83 2.3e3.6 2.92e4.17 2.46e6.62 (mean SD) 2.43e11.33 2.69e12.09 2.36e10.56 2.21e7.35

62 24 12 128 40 28 49 11 44

1961 1992 1994 1995 1998 1998 2004 2004 2006 2009

727 463 190 74

the Helsinki Accord. Students who participated in the academic program were taught to palpate the CRI and tested to establish their ability to monitor it. The data for this study were taken from these evaluations. The participants of this study (N ¼ 734) were practicing clinicians (predominantly physical therapists, with some nurses, midwives and medical doctors). They were undergraduate and postgraduate students of osteopathy. Most were studying at, or graduates of, La Maison de la Thérapie Manuelle, an osteopathic school that holds classes in different European cities. Their formal two year course of study in cranial osteopathy consisted of 225 contact hours, including 150 h of didactic and 75 h of laboratory work. It was presented within an extensive academic osteopathic curriculum, typically after two years of general osteopathic studies. The Level 1 individuals participated at the end of their first year of cranial osteopathic study. The Level 2 individuals participated upon completion of the course at the end of their second year of study. The Level 3 individuals, having successfully completed the two year cranial program, participated as attendees of postgraduate courses in cranial osteopathy. The demographics of the study population, with respect to the city and year in which the course was given, the level of participants, and their number at that site and year, are as follows: 60.2% (of the total enrolment) at Biscarrosse, France: [2001] Level 1, 86; [2002] Level 1, 50, Level 2, 32, Level 3, 35; [2003] Level 1, 48, Level 2, 31; [2004] Level 2, 52; [2005] Level 1, 59, Level 2, 49. 29.3% at Paris, France: [2002] Level 1, 42; [2003] Level 1, 15, [2004] Level 1, 74, [2006] Level 1, 58, Level 2, 26. 5.2% at Lyon, France: [2003] Level 1, 16, [2004] Level 1, 22. 5.3% at Padova, Italy: [2003] Level 3, 39. The % of the total number of subject/examiners at each level were 64.0% level 1, 25.9% level 2, 10.1% level 3. Data collection occurred at the end of the course at the same time in the academic schedule of each program. The time of day was variable depending upon each separate program’s schedule. The data were collected in the teaching laboratory with the subjects always being examined in the same position, supine upon the examination table. The data were collected in each instance by the same individual (NS). All participants palpated CRI rates on each other (734 different healthy individuals) within the controlled environment of the teaching laboratory. The groups were divided in half, with half of the group being examiners and the other half subjects. Upon completion of the protocol, the pairing was maintained and the individuals changed places, with the examiners becoming subjects and the subjects becoming examiners. With this structure, every participant was an examiner one time and a subject one time. At no time during and between both sessions was any communication between participating individuals permitted. The examiners were

11

asked to begin palpating the CRI using the classically described vault hold5,9 and given enough time, ca. 2 min, to sense the oscillation. Following this acclimatisation period, they were told when to start and when to stop counting the CRI. They were not told how long they would be palpating, only to count the number of complete biphasic CRI cycles that they palpated during the acquisition period. They were timed, using a wristwatch with a sweep second hand for a predetermined number of minutes (all trials, 3 min) known only to the individual conducting the protocol. It was determined by our previous work18e20 that this relatively brief time measurement window is sufficient to provide a good CRI sampling number without introducing error that could come with longer measurement periods. Following the data acquisition period, the investigator passed among the examiners and had them silently record their measured rate on a roll of paper after which that section of paper was torn from the roll and placed into an envelope. The reported number-of-cycles were kept private, and palpating participants were not aware of the rates that other participants reported. The investigator then moved to the next examiner and repeated the process until the rates acquired from all examiners had been gathered. Following this, the pairs exchanged positions, and the protocol was repeated. The numbers recorded on the paper fragments were tabulated on a spreadsheet identifying the experiential group and site. The CRI rate was then calculated in cycles/ min for each recorded value by dividing the total number of CRI cycles counted per subject by 3, the time in minutes allowed at each measurement session. 3. Statistical analysis Palpating participants were analyzed in three groups based upon their level of training and clinical experience: Level 1 (N ¼ 463) consisted of students with 1 year of experience who successfully palpated the CRI; Level 2 (N ¼ 190), 2 years of experience; Level 3 (N ¼ 74), 3e25 years of experience. Although 734 individuals participated in the study, seven Level 1 students did not palpate a CRI rate, yielding a valid subject population of 727 volunteers. Data frequencies and descriptive statistics were computed using the SPSS statistical package (SPSS, Inc., SPSS 10.1).21 The One-Way Analysis of Variance (one-way ANOVA) was used to assess whether a significant difference existed among the three experimental groups. In addition, pair-wise comparisons (of means) were performed among the three groups using both the Scheffé and the Least-Significant Difference range tests, with an alpha of .05 accepted as significant. Formal tests of normality were computed using the ShapiroeWilk and the KolmogroveSmirnov tests. The distributions obtained (histograms) were analyzed further for their deviations from normality using Normal QeQ plots and Detrended Normal QeQ plots. 4. Results Seven Level I participants (1.5%) were unable to perform the CRI rate determination, while all participants in Levels 2 and 3 successfully performed the CRI rate determination. The valid examiner/ subject population of the 734 potential pairings, therefore, was 727. The mean reported CRI rate (N ¼ 727) was (mean SD) 6.88 4.45 cycles per minute (Fig. 1 and Tables 2 and 3). Skewness (2.510 .091) and Kurtosis (11.389 .181) provide measures of the distribution (Table 2). (Skewness, or third moment, will take on the value of zero when the distribution is a completely symmetric bellshaped curve. Kurtosis, or fourth moment, is a measure of relative peakedness or flatness of the curve. A normal distribution will have a kurtosis of zero.21) The mean (SD) for each subgroup (Tables 1 and 3) is as follows: Level 1, 7.39 4.70; Level 2, 6.46 4.10; Level 3, 4.78 2.57 (Fig. 2).

12

N. Sergueef et al. / International Journal of Osteopathic Medicine 14 (2011) 10e16 Table 3 Cranial Rhythmic Impulse (CRI) rate partitioned by experience level: Descriptive Statistics.

140 120

Level N

100

Mean Std. Std. Deviation Error

80 1 463 7.392 4.700 2 190 6.458 4.102 3 74 4.775 2.570 Total 727 6.882 4.446

Frequency

60 40

.218 .298 .299 .165

95% Confidence Interval for Mean Lower Bound

Upper Bound

6.963 5.871 4.179 6.558

7.822 7.045 5.370 7.205

Minimum Maximum

1.00 1.33 1.33 1.00

39.33 33.67 13.33 39.33

All values except Level and N are reported as cycles per minute for data collection times of 3 min.

20 0 .9 38 .8 34 .7 30 .5 26 .4 22 .2 18 .1 14 .0 10 8 5. 7 1.

Observed CRI Value Fig. 1. Frequency histogram of cranial rhythmic impulse (CRI) rates. Each bar represents a CRI range of 1.38 cycles/minute (cpm); frequency is the number of the 727 participants in a given range (mean SD ¼ 6.882 4.446; N ¼ 727). The solid line depicts the standard deviation (SD) curve derived from the histogram. Note; because of the skewed nature of the CRI data, the normal distribution curve presented in the figure is truncated on the left because it is impossible to palpate a rate lower than zero.

One-way analysis of variance for levels 1, 2 and 3 was significant (P < 0.001). The Scheffé post hoc test showed that all three groups were different, one from the other (Fig. 2 and Table 4). In Fig. 3, parts A, B, and C, the histograms of Fig. 2 have been adjusted vertically so that the shape of the histograms is more apparent visually. Note that with increasing experience (Level 3), the width of the distribution is narrowest, and the skew is least. The maximum bars of the histograms, however, are located approximately at the same values of the CRI rate for all three groups. Analysis of distributions for each group is presented in the normal probability plots of Fig. 3, parts D, E, and F. If the data are from a normal distribution, the plotted values should fall roughly around the diagonal lines in Fig. 3, parts D, E, and F. Points falling off the line indicate deviation from a normal distribution. Fig. 3, parts D and E, are similar in appearance and fall below the normality line for both low and high CRI values, with the deviation from normal being greatest for Level 1 (Fig. 3, part D). Fig. 3, part F, is distinctly different. Here the distribution approximates normality because the data points fall close to the normative line.

Table 2 Cranial Rhythmic Impulse (CRI) rate from all valid participants: Descriptive Statistics (Rates are reported as cycles per minute for data collection times of 3 min). Statistics (All participants) N Valid Missing Mean Std. Error of Mean Median Mode Std. Deviation Variance Skewness Std. Error of Skewness Kurtosis Std. Error of Kurtosis Range Minimum Maximum

727 7 6.882 .1649 6 3.33 4.446 19.766 2.510 .091 11.389 .181 38.33 1.00 39.33

The data in Fig. 3, parts D, E, and F, are scaled identically to facilitate comparisons. Note that the slope of the lines move to the vertical from Level 1 through Level 3, indicating a tighter grouping of the data, i.e., the data from experienced practitioners is less scattered, which also is reflected in the values of the standard deviations (Table 3). Further analysis of the three distributions is presented in the detrended normal probability plots of Fig. 3, parts G, H, and I. These detrended plots can also be used to detect patterns of how the histogram data depart from normality. In these displays, the differences between the usual z score for each case and its expected score under normality are plotted against the CRI values (the scale on the vertical axis remains in standardized units). Here, since the plot line is horizontal, the vertical plot scale enlarges, magnifying the view of the configuration.21 (In a normal distribution, points will be scattered plus and minus about the horizontal line and will be clustered close to it.) Again, Fig. 3, parts G and H (Levels 1 and 2), show similar curved displays having large positive wings. These distributions lie far from the normal. In contrast, the distribution of Level 3 (Fig. 3, part I) lies close to the normal with only a single point being an outlier.

5. Discussion Why should we concern ourselves with the rate of the CRI? Cranial osteopathy, the PRM and the CRI are decidedly controversial, with a number of authors questioning their validity.1e4 Further, the fact that there were 22 years between the introduction of the cranial hypothesis7 and the initial use of the term cranial rhythmic impulse and the first publication of an observed rate for the CRI8 could lead one to wonder if the rate was of any great relevance to early practitioners. We would contend that resolution of the controversy over cranial osteopathy could come only from an acceptable understanding of its underlying physiology. As stated earlier, the CRI is an observable (palpable) rhythmic fluctuation believed to be synchronous with the PRM.6 As an observable phenomenon associated with the PRM, the central concept in cranial osteopathy, it offers access for the study of the cranial hypothesis. Yet measured rates for the CRI tend to vary sufficiently from one study to another (Table 1) as to call into question what is being measured. Since it is assumed to be a biological rhythm, the CRI should have a normative rate and range. Identifying these values will allow better understanding of the phenomenon and possibly provide access to further study of the underlying physiology and therapeutic impact of cranial osteopathy. Having normative values for the CRI also will aid in the teaching of cranial osteopathy. If a student has a clearly defined idea as to the rate of the physiological rhythm they are trying to learn to palpate, the objective of their studies becomes easier to identify. Testing a student’s ability to palpate also will be facilitated. The use of a window of observation, similar to that employed in this protocol,

N. Sergueef et al. / International Journal of Osteopathic Medicine 14 (2011) 10e16

13

Fig. 2. Frequency histograms of cranial rhythmic impulse (CRI) rates partitioned by level of training. Level 1, 1 yr (N ¼ 463); Level 2, 2 yr (N ¼ 190); Level 3, 3e25 yr (N ¼ 74). Each bar represents a CRI range of 1.43 counts per minute (cpm); frequency is the number of the total 727 participants in a given range for each training level.

becomes a feasible testing tool if well-documented rates for the CRI are available. The establishment of normative values in the clinical sciences, however, ordinarily means the conduct of studies with large N numbers. This study provides a statistical N of 727 subjects (Tables 1 and 2). This number of cases (all different subjects) is 83% larger than the sum of all comparable studies identified in Table 1. Both the reported CRI rate means and standard deviations in this current study showed an inverse relationship with the level of examiner experience, i.e., as experience increased, means and standard deviations decreased. This is consistent with what one would expect: (1) beginning level students ought to show a greater range of palpatory results because of an increased possibility for error (increased SD), (2) the intermediate training level’s values would fall somewhere between beginners and experienced practitioners, and (3) the more experienced examiners should be capable of more precisely palpating the CRI, yielding a decreased variance. The data do show that these

variance expectations for the three levels are valid (Table 3, means; Table 4, multiple comparisons), with the experienced group demonstrating an SD that approximates half that of the two less experienced groups. During the implementation of the protocol the CRI counting period was reasonably short, 3 min, and it was the same in all instances, even though the participants did not know for how long they were counting. The data from the experienced practitioners presented in Table 3 and Fig. 3 demonstrates that the CRI values were reasonably closely clustered for the experienced group. This indicates that the experimental protocol was, therefore, reasonably well designed and that the spread in CRI values observed for the two less experienced groups was the result of practitioner inexperience and not the result of a poorly designed protocol. Further, and in support of the reliability of experienced examiners, are respective histograms of Levels 1, 2, and 3 CRI values and their analyses through normal probability and detrended normal probability plots (Fig. 3). These plots demonstrate that CRI values

Table 4 Statistical significance of differences in results among the three educational levels. Levels Compared

Difference Between Mean Rates

(I)

(J)

(I e J)

1 1 2

2 3 3

.935 2.618 1.683

Std. Error

.377 .548 .600

All values except Level and P are cycles per minute. a The mean difference is significant at the .05 level (Scheffé multiple comparisons).

95% Confidence Interval For the Difference Between Means Lower bound

Upper bound

.0096 1.2737 .2122

1.8593 3.9615 3.1540

P

.047a

International Journal of Osteopathic Medicine- Volume 14, Issue 1 (March 2011)

Clinical Chiropractic- Volume 14, Issue 1 (March 2011)

sports medicine Volume 41 Issue 3 March 2011

Journal of Chiropractic Medicine- Volume 9(1); March 2010

International Journal of Powder Metallurgy Volume 44 Issue 1

International Journal of Powder Metallurgy Volume 45 Issue 1

International Journal of Powder Metallurgy Volume 46 Issue 1

Redline (March 2011, Issue 165)

Woodworker's Journal - March-April 2011

sports medicine Volume 41 Issue 1 January 2011

Reflections Journal Issue 1

Foundations of Osteopathic Medicine

Physiotherapy, Volume 97, Issue 1 (2011)

Israel Journal of Mathematics, Volume 1, Issue 1 (1963)

Journal of Semantics, Volume 1, Issue 1, 1982

Cell Journal, 1 April, 2011 Volume 145, Issue 1 pp. 1-162

International Journal of Powder Metallurgy Volume 44 Issue 2

International Journal of Contemporary Iraqi Studies Volume 5 Issue 2

sports medicine Volume 40 Issue 3 March 2010

International Journal of Powder Metallurgy Volume 45 Issue 3

International Journal of Powder Metallurgy Volume 45 Issue 2

International Journal of Powder Metallurgy Volume 43 Issue 6

International Journal of Powder Metallurgy Volume 45 Issue 6

International Journal of Powder Metallurgy Volume 46 Issue 3

International Journal of Powder Metallurgy Volume 46 Issue 6

International Journal of Powder Metallurgy Volume 45 Issue 4

International Journal of Powder Metallurgy Volume 46 Issue 5

International Journal of Powder Metallurgy Volume 44 Issue 6

sports medicine Volume 39 Issue 3 March 2009

International Journal of Osteopathic Medicine- Volume 14, Issue 1 (March 2011)

Clinical Chiropractic- Volume 14, Issue 1 (March 2011)

sports medicine Volume 41 Issue 3 March 2011

Journal of Chiropractic Medicine- Volume 9(1); March 2010

International Journal of Powder Metallurgy Volume 44 Issue 1

International Journal of Powder Metallurgy Volume 45 Issue 1

International Journal of Powder Metallurgy Volume 46 Issue 1

Redline (March 2011, Issue 165)

Woodworker's Journal - March-April 2011

sports medicine Volume 41 Issue 1 January 2011

Reflections Journal Issue 1

Foundations of Osteopathic Medicine

Physiotherapy, Volume 97, Issue 1 (2011)

Israel Journal of Mathematics, Volume 1, Issue 1 (1963)

Journal of Semantics, Volume 1, Issue 1, 1982

Cell Journal, 1 April, 2011 Volume 145, Issue 1 pp. 1-162

International Journal of Powder Metallurgy Volume 44 Issue 2

International Journal of Contemporary Iraqi Studies Volume 5 Issue 2

sports medicine Volume 40 Issue 3 March 2010

International Journal of Powder Metallurgy Volume 45 Issue 3

International Journal of Powder Metallurgy Volume 45 Issue 2

International Journal of Powder Metallurgy Volume 43 Issue 6

International Journal of Powder Metallurgy Volume 45 Issue 6

International Journal of Powder Metallurgy Volume 46 Issue 3

International Journal of Powder Metallurgy Volume 46 Issue 6

International Journal of Powder Metallurgy Volume 45 Issue 4

International Journal of Powder Metallurgy Volume 46 Issue 5

International Journal of Powder Metallurgy Volume 44 Issue 6

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