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Sue Shekut: Seeking feedback on massage research design

Submitted by RST on Sun, 03/25/2012 - 19:18
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The following is the same text that is contained in the 2 PDFs attached to this page.

This page is searchable text for finding from the POEM home page and for commenting on, but only the PDFs contain the correct and authoritative formatting of the document.

 

March 24, 2012

Fellow POEM Members,

I am submitting my research design, “Massage Therapy Modality Effect on Blood Pressure, Cortisol and Anxiety“ to POEM for feedback from POEM members and suggestions on how to best operationally define the different modalities of massage therapy for research.

My goals in submitting this particular research design to POEM are:

  1. To give other massage therapists (MTs) a template for writing similar studies.
  2. To find like-minded MTs that may want to contribute to this study/elements of this study and perhaps do the actual research.
  3. To show other MTs that writing research designs is not that hard, can be done by an MT, and follows a standard format.
  4. To make sure that the work I put in thus far does not just sit in my computer gathering "dust".

 

The design isn't the best ever, but it addresses some of the issues we all face in design research for massage therapy.

 

My specific questions to fellow POEM members are as follows:

  1. Is the operational definition I include of deep tissue, Swedish and sports massage clear enough for others to replicate? Is it accurate?
  2. Does a specific protocol for each modality need to be defined for the study design?
  3. Does a specific protocol for each modality need to be defined for MTs that provide massage to ensure objective application of the modalities for each research subject?
  4. Are these three modalities the best representation of diverse types of massage for studying effects of BP, cortisol and anxiety? Would including other modalities or breaking down deep tissue into trigger point work and mysofascial release provide more useful data?
  5. Does the study need to operationally define “light, moderate and firm” pressure or is the subjective appraisal of pressure by MTs giving the massage of each level of pressure sufficient? If not, how best to operationally define pressure levels? Who defines pressure levels? The MTs, each research subject?

 

Note that I wrote the bulk of this design in 2010 and had not yet read Christopher Moyer's study on cortisol and massage. However, since Moyer’s study was not an experimental study, but a meta-analysis of previous research, I believe that further experimental research on the effects of massage on cortisol levels is warranted.

I welcome comments, feedback and offers of collaboration for this research project. Even if no one ends up conducting this particular research project, I hope that by reading and reviewing my work, other MTs may be empowered to conduct their own research and further the evidence base of the massage profession.

Warmly,
Sue Shekut, Licensed Massage Therapist
Graduate student in Clinical Professional Psychology at Roosevelt University

 

Massage Therapy Modality Effect on Blood Pressure, Cortisol and Anxiety
Susan J. Shekut
Roosevelt University
© 2012, Sue Shekut

Abstract

Stress management is an important issue in the workplace and for the individual. Massage therapy has been shown to reduce depression and anxiety as well as to reduce levels of cortisol and reduce blood pressure (BP). Massage modality can moderate the effect of onset of BP reduction and may moderate the effect of onset of cortisol reduction as well as self-reported anxiety levels. There are a number of types of massage, but for this study, only deep tissue, sports massage and Swedish massage styles were examined as to their effect on the blood pressure, cortisol and anxiety levels of 90 participants. It is expected that Swedish massage will decrease BP, cortisol and self reported anxiety to the greatest degree immediately following the massage intervention and that deep tissue and sports massage will have greater effects on BP, cortisol and anxiety reduction two days post massage intervention.

Massage Therapy Modality Effect on Blood Pressure, Cortisol and Anxiety

Workplace stress has recently been indicated to be one of the major causes of some of the costliest, most time-robbing health problems for business. According to the 17th World Congress on Health and Safety at Work, 13.4 million working days are lost due to stress, anxiety, and depression (17th World Congress on Health and Safety at Work).

Traditional approaches to stress management include psychological interventions such as cognitive behavioral therapy, mediation, diaphragmatic breathing and similar self-directed techniques (David & McKay, 2008). However, there is a growing trend among consumers to seek massage therapy as a form of stress relief. In a consumer survey published by the American Massage Therapy Association (AMTA) in 2009 found that 32 percent of Americans said they got a massage for stress and/or relaxation in the last five years.

Some believe the mechanism of effect for massage therapy may be primarily psychological (Moyer, Rounds, & Hammum, 2004). Others believe massage has a physiological effect as well. Studies show that massage therapy can be effective for anxiety and depression as well as a host of clinical conditions (Rich, 2010). Additionally, current research findings has shown that a single session of massage therapy reduces state anxiety, blood pressure and heart rate, and multiple sessions of massage reduce delayed onset of pain (Moyer, et al., 2004). Other studies show that participants’ salivary cortisol levels decreased following massage therapy (Field, et all, 1997). Yet none of these studies tested whether a specific massage therapy modality was responsible for producing these affects.

The Touch Research Institute of Miami University, a noted research facility in the field of massage therapy, has conducted a number of studies demonstrating the physiological effects of massage therapy. One of their studies found that healthy adults that received 15-minute chair massages twice per week for five weeks had marked improvement in EEG patterns of alertness and frontal delta power increases, which suggests relaxation (Field, et al., 1996). The massage recipients also showed increased speed and accuracy on math computations, lower anxiety levels, as well as lowered salivary cortisol levels on the first day of treatment. However, BP levels were not tested at all in this study–only anxiety and cortisol levels were tested.

Corporate companies have been using massage therapy as a reward and stress intervention for the past 10-15 years (reference). A 1996 (Shulman & Jones) quasi-experimental field study found significant reductions in anxiety levels for massage recipients as measured by the State-Trait Anxiety Inventory Self-Assessment Questionnaire. Researchers found that residual effects of the massage continued after cessation of the massage intervention and that there was a trend for stress levels to be more greatly reduced for those massage recipients that worked more than 40 hours per week and had higher education levels. However, they did not test the effect of the intervention on BP levels, cortisol levels or participants’ anxiety levels in this study.

Fifteen-minute chair massages on healthcare workers at a major hospital decreased job stress, anxiety and depression as well as decreased in urinary cortisol (Field, Quintino, Henteleff, Wells-Kief, & Delvecchio-Fienerg, 1997). However, chair massages can include a variety of massage modalities depending on the training of the massage therapists providing the massage intervention. Neither the massage modality was addressed nor was the massage intervention operationally defined in this study. Participant BP levels were not investigated either.

Field and her colleagues reviewed various massage studies and overall found that massage therapy decreases cortisol levels and increases urinary serotonin and dopamine levels (Field, Hernandez-Reif, & Diego, 2005). While Field and colleagues claim that the reduction in cortisol suggests that massage had stress-alleviating effects and that increases in urinary serotonin and dopamine suggest that they help reduce depression and the effects of stress, there is no significant relationship between serotonin and dopamine secreted in the urine and the amount of these neurotransmitters in the brain. Research has shown that neurotransmitters do not cross the blood brain barrier. According to a recent study published in the Journal of Urology, urinary serotonin and urinary dopamine do not show levels of serotonin and dopamine that were previously in the central or peripheral nervous system. Urinary serotonin and urinary dopamine are synthesized in the kidneys, not in the central nervous system (Hinz, Stein, Trachte, & Uncini, 2010). Therefore, measuring urinary levels of neurotransmitters is not a definitive test to measure depression or anxiety nor to test the effects of massage therapy on depression or anxiety. However, testing salivary cortisol is an accepted method of testing the changes in unbound cortisol in participants, due to the validity of salivary cortisol reflecting the level of cortisol in the blood and the relative ease with which salivary cortisol may be obtained from participants. Habitual smokers tend to show blunted cortisol responses to psychological stress and therefore should not be included in studies that measure cortisol changes in response to stress effecting interventions (Kirschbaum & Hellhammer, 1993).

Since blood pressure tends to increase with stress and the sympathetic nervous system response, measuring blood pressure changes has been one method researchers use to examine physiological effects of massage (Smith, T. W., Birmingham, W., & Uchino, 2012; Cambron, Dexheimer, & Coe, 2006). This would suggest that measurements of changes in BP may be a good physiological measurement of anxiety levels to assess effects of massage therapy. In a preliminary study, 150 adults with “normal” BP (under 150/95) were given different types of massages to determine the effect on blood pressure. Overall blood pressure decreased for massage recipients of all types of massages. However, those that received Swedish massages had the greatest effect on BP reduction. Trigger point and sports massage styles tended to increase systolic BP. If both sports and trigger point therapy massage were used in one session, then both diastolic and systolic BP increased. However, these results were not statistically significant. Blood pressure was measured using an automatic cuff which may have resulted in less accurate readings but the study authors were not concerned with measuring actual BP changes, but the overall effect of the massages on BP. Another potential threat to internal validity of this study was that the massage therapy students conducting the massages self reported the style of techniques they used. Additionally, the study was a case study and not powered for multiple statistical tests. Future researchers were recommended to use manual BP cuffs and provide for tighter controls on the type of massages used (Cambron, Dexheimer, & Coe, 2006).

Recent studies examined the effects of the level of pressure of massages given to participants to determine if light, moderate pressure, or vibratory massage would have a greater effect on parasympathetic nervous system activity (Diego, Field, Sanders, & Hernandez-Reif, 2004). Massage recipients felt less anxiety following massage sessions no matter what pressure
was used. However, those that received moderate pressure massages reported the greatest decreases in self-reported stress. The moderate massage group showed a significant decrease in heart rate during the massage, which continued into the post massage session.

Field and a colleague followed up this study with research on the effect of moderate pressure massage on EKG readings to determine if a parasympathetic response was the result of moderate pressure massage (Diego, Field, , Sanders, . & Hernandez-Reif, 2004). Results indicated that participants that received the moderate pressure, 15-minute massage showed an increase in high frequency ratio components of heart rate variability. This suggested an increase in parasympathetic nervous system activity. The study contended that the mechanism for action in increasing parasympathetic response was the stimulation of pressure receptors in the skin (Diego & Field, 2009). While yielding useful data as to the effects of the level of pressure, neither of these latter two studies measured BP levels, cortisol levels, or participant anxiety, only the heart rate variability of participants.

Despite the growing volume of research on massage therapy, none of these studies compare modality (type) of massage given to changes in cortisol levels, changes in BP levels or changes in perceived anxiety levels. Since previous studies show that BP increases with massage that produces more painful responses (trigger point therapy, sports massage and deep tissue), it is expected that cortisol levels, a measure of the stress response, will respond similarly to BP on the types of massage interventions. Since psychological stress has been shown to increase cortisol levels, it is expected that self reported anxiety levels will correlate with levels of BP and cortisol.

Swedish massage (which tends to be a more moderate pressure style of massage), deep tissue massage and sports massage tend to be deeper pressure massage modalities (AMTAWashington, 2010). Massage recipients typically report feeling the most relaxing effects of a deep tissue or sports massage a few days after the massage session as the initial effects may include soreness and fatigue. These results would be assessed post massage and then 2 days after the massage session.

Hypothesis 1: Blood pressure levels will be negatively correlated with Swedish massage therapy immediately following the intervention.

Hypothesis 2: Blood pressure levels will be negatively correlated with deep tissue and sports massage two days post intervention.

Hypothesis 3: Salivary cortisol levels will be negatively correlated with Swedish massage therapy immediately following the intervention.

Hypothesis 4: Salivary cortisol levels will be negatively correlated with deep tissue and sports massage two days post intervention.

Hypothesis 5: Self reported anxiety levels will be negatively correlated with Swedish massage therapy immediately following the intervention.

Hypothesis 6: Self reported anxiety levels will be negatively correlated with deep tissue and sports massage two days post intervention.

Method

Participants

The sample would include approximately 90 participants from an large city in the Midwest. They would be recruited from the area via fliers sent to area offices as well as at nearby retail stores. It would be expected that participants would be fairly well educated, both male and female of middle to upper middle socioeconomic status, and be representative of a variety of races and demographics of this area.

Participants would be ages 25-55, of normal health, no hypertension or heart disease (BP under 140/90–the threshold for indicating hypertension), be nonsmokers, not be pregnant and have no history of severe mental illness (e.g., depression, bipolar, schizophrenia). Participants would be screened to ensure that they had previously received massages and have had positive experiences with massage, but had not received massages for at least 6 months prior to the study. Participants would be randomly assigned to Swedish, Deep Tissue. and Sports massage groups. Participants would be blind to the type of massage they are being given. A short questionnaire would be included with their two-day follow up anxiety test to assess whether they knew the type of massage they were given. Participants would be instructed to avoid salty foods between the massage intervention and the two-day follow up. Incentive to return for their two-day follow up would be the receipt of a gift certificate for a 30-minute massage (modality of their choice) to be completed at a later date.

BP Testing Procedures

BP would be measured via a manual BP cuff 5 minutes prior to massage intervention and 5 minutes after the intervention. At two day follow up the BP will again be measured. Recordings of Diastolic and Systolic BP would be made for both pre and posttests. Changes in BP for each participant would be recorded.

Cortisol Testing Procedures

Salivary cortisol testing procedure would be conducted in the following order: Premassage session salivary samples would be taken 3 minutes prior to massage; Post massage, another salivary sample would be taken 3 minutes prior to massage; Two days after the massage intervention, a salivary sample would also be taken.

Anxiety Testing Procedures

The State-Trait Anxiety Inventory Form (STAI) will be used to measure anxiety in participants. The STAI clearly differentiates between the temporary condition of "state anxiety" and the more general and long-standing quality of "trait anxiety." (Spielberger, 1994). Participants will be given the STAI 10 minutes prior to the massage, 10 minutes after the
massage and two days after the massage.

Massage Interventions

Massages would be provided by three Licensed Massage Therapists with at least five years of full-time work experience in massage therapy and with advanced training in the types of massage they are to perform (Swedish, deep tissue and sports massage).

Massage therapists would be instructed to provide either a 30-minute session of Swedish massage on the upper torso, a 30 minute session of deep tissue massage on the back (including infraspinatus, rhomboids, trapezius, erector and quadratus lumborum muscles), or a 30-minute session post-event Sports massage session on the upper torso. Each massage therapist would provide a different type of massage to different participants to avoid experimenter bias from influencing results. Massages would be provided in the same room in the same office to hold environmental differences constant.

Types of massage will be operationally defined per the definition provided by Milady’s Theory and Practice of Therapeutic Massage as follows (Beck, 1994).

Deep tissue message. “The term deep tissue massage refers to various regimens or massage styles that are directed toward the deeper tissue structures of the muscle and fascia…In most deep tissue massage techniques the aim is to affect the various layers of fascia that support muscle tissues and loosen bonds between layers of connective tissues” (Beck, 1994, p. 548).

Sports massage. “Sports massage refers to a method of massage especially designed to prepare an athlete for an upcoming event and to aid in the body’s regenerative and restorative capacities following a rigorous workout or competition. This is achieved through specialized manipulations that stimulate circulation of the blood and lymph. Some sports massage movements are designed to break down lesions and adhesions or reduce fatigue” (Beck, 1994, p.16).

Swedish message. “The Swedish system is based on the Western concepts of anatomy and physiology and employs the traditional manipulative techniques of effleurage, petrissage, vibration, friction and tapotement” (Beck, 1994, p. 15). All three types of massage would be administered using moderate and not light pressure based on previous study findings that moderate pressure massage stimulates parasympathetic NS activity more so than light pressure massage.

Anticipated Results

Based on results of previous research noted in this study, it is expected that recipients of Swedish massage will have the greatest reduction in both BP and cortisol levels immediately following the massage. However, we also expect to find that BP and cortisol levels will be reduced more for the deep tissue and sports massage group than the Swedish massage group two days after receiving the massage intervention. It is expected that recipients of Swedish massage will report the least anxiety immediately posttest and that the recipients of deep tissue and sports massage will report the least anxiety two days post test. Results will be analyzed using one-way ANOVA tests.

References

AMTA-Washington chapter (2010) Retrieved from: http://www.amtawa.org/index.php?src=gendocs&ref=Modalities&category=Reso...

Beck, M. (1994). Milady's theory and practice of therapeutic massage. (2nd ed.). Albany: 1994 Milady Publishing Company.

Calvert, R. N. (2010) A Brief History of Massage. Retrieved from: http://www.massagetherapy.com/media/experiencehistory.php

Cambron, J. A., Dexheimer, J. & Coe, P. (2006) Changes in blood pressure after various forms of therapeutic massage: A preliminary study. The Journal of Alternative and Complimentary Medicine, 12(1), 65-70.

Davis, M., Eshelman, E., & McKay, M. (2008). The relaxation and stress reduction workbook (6th ed.). Oakland, CA US: New Harbinger Publications.

Diego, M. A., & Field, T. (2009) Moderate pressure massage elicits a parasympathetic nervous system response, International Journal of Neuroscience, 119, 630-638.

Diego, A., Field, T., Sanders, C. & Hernandez-Reif, M. (2004). Massage therapy of moderate and light pressure and vibrator effects on EEG and heart rate. International Journal of Neuroscience, 114, 31-45.

Field, T., Hernandez-Reif, (FI?) & Diego, M. (2005) Cortisol decreases and serotonin and dopamine increase following massage therapy. International Journal Neuroscience, 115, 1397-1413.

Field, T., Diego, M. & Hernandez-Reif, M. (2010) Moderate pressure is essential for massage therapy effects. International Journal of Neuroscience, 120, 381-385.

Field, T., Ironson, G., Scafidi, F., Nawrocki, T., Goncalves, A., Burman, I., Pickens, J., Fox, N., Schanberg, S., & Kuhn, C. (1996). Massage therapy reduces anxiety and enhances EEG pattern of alertness and math computations. International Journal of Neuroscience, 86, 197-205.

Field, Tiffany, Hernandez-Reif, M., Hart, S., Quintine, O., Droase, L. A., Field, T.,… & Schanberg, S. (1997) Effects of sexual abuse are lessened by massage therapy. Journal of Bodywork and Movement Therapies, 1(2), 65-69.

Field, T., Quintino, O., Henteleff, T., Wells-Kief L. & Delvecchio-Fienerg G. (1997). Job Stress reduction therapies. Alternative Therapies in Health and Medicine 3(4), 54-56.

Hinz, M., Stein, A., Trachte, G. & Uncini, T. (2010) Neurotransmitter testing of the urine, a comprehensive analysis. Journal of Urology, 2010(2), 177-183.

Kirschbaum, C. & Hellhammer, D., H. (1993) Salivary cortisol in psychoneuroendocrine research: Recent developments and applications. Psychoneuroendocrinology, 19(4), 313-333.

Kharrazian, D. (2009) Understanding the clinical relevance and non-validity of neurotransmitter testing. AlaimoChiropractic.com. Retrieved from: http://alaimochiropractic.com/urinaryneurotransmitter-testing-valid-or-h...

Moyer, C. A., Rounds, J, & Hannum, J. W. (2004). A meta-analysis of massage therapy research. Psychological Bulletin, 130(1). 3-18.

Ponce, A. N., Lorber, W., Paul, J. J., Esterlis, I., Barzvi, A., Allen, G. J., & Pescatello, L. S. (2008) Comparisons of varying dosages of relaxation in a corporate setting: Effects on stress reduction. International Journal of Stress Management 15(4), 396-407.

Rich, G. J. (2010). Massage therapy: Significance and relevance to professional practice. Professional Psychology: Research and Practice, 41(4). 325-332.

Schulman, K. R., & Jones, G. E. (1996) The effectiveness of massage therapy intervention on reducing anxiety in the workplace. Journal of Applied Behavioral Science, 32(2), 160-173.

Smith, T. W., Birmingham, W., & Uchino, B. N. (2012). Evaluative Threat and Ambulatory Blood Pressure: Cardiovascular Effects of Social Stress in Daily Experience. Health Psychology. Advance online publication. doi: 10.1037/a0026947

Spielberger, C. D., & Sydeman, S. J. (1994). State-Trait Anxiety Inventory and State-Trait Anger Expression Inventory. In M. Maruish, M. Maruish (Eds.) , The use of psychological testing for treatment planning and outcome assessment (pp. 292-321). Hillsdale, NJ England: Lawrence Erlbaum Associates, Inc.

Williams, A. (2005). Work-Related Stress Emerging as Major Global Occupational Health Hazard, National Safety Council press release. Retrieved from:http://www.nsc.org/Pages/Work-RelatedStressEmergingasMajorGlobalOccupationalHealthHazard.aspx

Citizen science: Want to participate in the development of a research questionnaire for neck and back pain?

Submitted by RST on Fri, 12/02/2011 - 10:35
Posted in

The Clinical Whiplash Intervention and Prognosis Research Group is seeking volunteers who have experienced back or neck pain to provide feedback on the usefulness of a new questionnaire designed to measure recovery from pain or injury in those conditions.

You will be required to provide a valid email address for them to contact you at, and they say that the study should take no more than about 15 minutes of your time. You can also opt in to a voluntary drawing for 2 $50 Amazon gift certificates after you have participated, which will be given to 2 of the participating volunteers chosen at random.

More information on participating in the survey evaluation is available at this link.

POEM report: 17 October 2011

Submitted by RST on Mon, 10/17/2011 - 13:17
Posted in

 

POEM has now been online for 6 weeks, and will be publishing its first Report Card for your evaluation at the end of this month.

In the meantime, I'll be involved in the following activities between now and putting out the Report Card at the end of October:

  • delivery of a proposal for a community-college-level certificate program, and advanced specialty CE classes to a Puget-Sound-area community college;
  • delivery of a similar proposal, although at the level of university professional education, to a Puget-Sound-area university;
  • networking with a local women's business group to promote awareness of POEM, and to evaluate their free resources for the use of POEM community members;
  • exploring the possibility of collaboration with a local refugee community-assistance group to help them with vocational education, and to record their knowledge of how their traditional massage is practiced.

 

The Report Card will contain a full description of these and other activities to support educational activities and resources for the community of MT stakeholders, as well as reporting about the progress made on them to date.

Source: http://www.ashes.ccs.k12.nc.us/Home%20page/Report_Card/report%20card.jpg accessed 17 October 2011

Let's read together: A Randomised Controlled Single-Blind Trial of the Efficacy of Reiki at Benefitting Mood and Well-Being--Introduction

Submitted by RST on Mon, 10/03/2011 - 09:27
Posted in

A link to the free fulltext PDF article is here.

 

Introduction

Reiki is a system involving the laying on of hands developed in Japan in the early 20th century [1] and is believed to have the capacity to heal the physical body and mind and bring emotional and spiritual balance.

 

"Is believed" drastically overstates the case--as the claim is written, it implies "believed universally", and Reiki is far from universally accepted. "Is believed by its practitioners" or "is believed by its adherents" would be a far more accurate description of the acceptance of Reiki.

Compare "The gate control theory is believed to provide a physiological explanation for the practice of rubbing a painful area" [A] and "The bear spirit Otso is believed to have been born in the regions of the Moon-land, on the shoulders of Otava, with the daughters of creation" [B].

Which sentence is an accurate statement of an almost universal consensus, and which statement needs modification to make clear that it is not a universal belief, but that of a specific minority of adherents? 

I know that this is their goal in this article--to demonstrate, using scientific methods, that Reiki deserves universal acceptance. But they actually have to do that work of connecting the dots and demonstrating the scientific credibility first, before claiming that it is already true.

This is the heart of science, and is what distinguishes it from philosophy, apologetics, and other pursuits. You have to do the actual work first; you cannot claim it, simply based on possibilities, or what is imaginable. In the upcoming sentence, they say "While the majority of scientific investigations [of Reiki] have suffered from design limitations...". That means that the work has not yet been done correctly, and so it has not yet been done.

If we are going to apply science to this exploration of Reiki, then we have to do it rigorously. Anything less is a waste of all of our time, money, emotional energy, and other resources. And I believe we all have a lot to offer our clients in the way of support, caring presence, and therapeutic alliance, whether or not the specific mechanism of what is offered is scientifically plausible or not. If we're not going to do the science rigorously, then we're wasting time and other resources that, in the long run, are better spent with clients.

This may sound like quibbling--I hear the phrases "mere semantics" and "semantic games" a lot. But semantics is the study of meaning, and what could possibly be more important than the meaning we communicate to ourselves, our clients, and each other?

Along those same lines, what do the expressions "heal the physical body and mind" and "bring emotional and spiritual balance" mean? Those are extremely vague, and that vagueness makes it impossible to pin down to evaluate objectively whether Reiki does what it claims to do or not.

For example, a leg is part of the physical body, so does "heal the physical body" mean restoring an amputated leg? If not, why not? What does it apply to, and why are those parts of the physical body different from the physical leg?

Does "healing the mind" and "bring emotional balance" mean that a schizophrenic receiving Reiki can safely come off of his medications? If not, then similar questions to those about the leg apply here as well. What is spiritual balance, and how do we tell when someone is in or out of it?

If claims are vague enough that they are untestable, then they are not scientific. Which is fine if you want to do something other than science, but for carrying out science, they don't really convey any meaning that we can practically use in evaluating them.

 

While the majority of scientific investigations have suffered from design limitations, however, there is some suggestive evidence that Reiki can influence mood [2–4] and induce physiological change in humans [5–10] and animals [11].

 

"The majority of scientific investigations [of Reiki] have suffered from design limitations" means that most research that claims to support Reiki does not stand up under examination, because the methodology--the most important part of the study--was flawed.

So we'll be looking at this study, and the one it was based on, to see how Bowden and her team avoid falling into those methodological traps.

However, the studies she cites as "suggestive evidence" seem to have methodological problems as well.

Wardell 2001, for example, uses a convenience sample and no control group, and is subject to the within-group measures problem that we discussed in Journal Club last month.

Baldwin 2006 points out that:

In the rat, stress from noise damages the mesenteric microvasculature, leading to leakage of plasma into the surrounding tissue.

 

and then makes the leap that because 4 rats showed less microvascular leakage in the mesentery after 3 treatments, that therefore Reiki minimizes environmental stress in human hospital patients.

It's a huge leap, but perhaps not an impossible one--but to show it's not impossible, you have to actually do the work of connecting the dots and showing how you demonstrated clearly that the effect must be due to Reiki and not something else. You can't just assume it and plow forward, not if we are to do real and rigorous science.

 

The present study employed a similar design to a previous study by the authors [4], where 35 first year undergraduates were randomly assigned to ten 20-minute sessions of Reiki or no-Reiki in conjunction with self-hypnosis/guided relaxation over a period of two and half to twelve weeks. While the Reiki group had a tendency towards a reduction of symptoms of illness following the intervention, a substantive increase in symptoms was seen in the no-Reiki group—leading to a highly significant distinction between them. There was also a trend for the Reiki group to have a greater improvement in overall mood than the no-Reiki group, accompanied by a near-significant comparative reduction in stress. However, the Reiki group had significantly higher baseline illness symptoms and mood scores than the no-Reiki group. The current study sought to replicate the comparatively greater mood and health benefits of the Reiki group in the previous study, while employing a design that ensured that the mean scores of the groups did not differ at baseline. In addition, the inclusion of participants with high depression and/or anxiety permitted the possibility that a greater degree of improvement could occur than was the case with the normally healthy participants of the first study.

 

I find this paragraph confusing--were the undergraduates properly randomly assigned, which would level out variations like higher baseline illness symptoms and mood scores between the two groups? Or were the two groups systematically different from each other, in which case they are, by definition, not properly randomized?

What she is saying sounds contradictory, and I can't be sure of exactly what is going on from the level of detail provided here. But one thing I can be sure of, however, is that if the Reiki group had "significantly" higher illness symptoms and mood scores, then several confounds, including regression to the mean and (UPDATE: corrected my misspelling of "vis") vis medicatrix naturae (the healing power of nature, the tendency for the body to heal itself of many illnesses) can have made an effect for which Reiki then incorrectly got the credit.

We will look in the Methods section next to see how they screened for such confounds, as well as for the fact that--as psychosocial beings--we respond psychologically and socially in ways that can be described as healing body and mind due to presence and caring attention from others. How they teased out Reiki from these effects, and how they determined what was caused by Reiki as opposed to something else, will be a very important part of our analysis.

 

 

References from the original article used in this section

1. Miles P, True G. Reiki—review of a biofield therapy history, theory, practice, and research.Alternative Therapies in Health and Medicine. 2003;9(2):62–72. [PubMed]
2. Dressen LJ, Singg S. Effects of Reiki on pain and selected affective and personality variables of chronically ill patients. Subtle Energy and Energy Medicine. 1998;9:51–82.
3. Shore AG. Long-term effects of energetic healing on symptoms of psychological depression and self-perceived stress. Alternative Therapies in Health and Medicine. 2004;10(3):42–48. [PubMed]
4. Bowden D, Goddard L, Gruzelier J. A randomised controlled single-blind trial of the effects of Reiki and positive imagery on well-being and salivary cortisol. Brain Research Bulletin. 2010;81(1):66–72.[PubMed]
5. Wetzel W. Reiki Healing: a physiologic perspective. Journal of Holistic Nursing. 1989;7(1):47–154.
6. Wirth DP, Chang RJ, Eidelman WS, Paxton JB. Haematological indicators of complementary healing intervention. Complementary Therapies in Medicine. 1996;4(1):14–20.
7. Wirth DP, Brenlan DR, Levine RJ, Rodriguez CM. The effect of complementary healing therapy on postoperative pain after surgical removal of impacted third molar teeth. Complementary Therapies in Medicine. 1993;1(3):133–138.
8. Wardell DW, Engebretson J. Biological correlates of reiki touch(Service mark) healing. Journal of Advanced Nursing. 2001;33(4):439–445. [PubMed]
9. Kumar RA, Kurup PA. Changes in the isoprenoid pathway with transcendental meditation and Reiki healing practices in seizure disorder. Neurology India. 2003;51(2):211–214. [PubMed]
10. Mackay N, Hansen S, McFarlane O. Autonomic nervous system changes during Reiki treatment: a preliminary study. Journal of Alternative and Complementary Medicine. 2004;10(6):1077–1081.
11. Baldwin AL, Schwartz GE. Personal interaction with a Reiki practitioner decreases noise-induced microvascular damage in an animal model. Journal of Alternative and Complementary Medicine.2006;12(1):15–22.
 

References I used in this section

[A] Melzack R, Wall PD. Pain mechanisms: a new theory. Science. 1965;150(3699):971–9. PMID 5320816. Free fulltext PDF available at this link.

[B] http://www.sacred-texts.com/neu/kveng/kvrune46.htm accessed 3 October 2011.

 

 

So that's what I've gotten our of the Introduction. Did you get anything else from it?

Please share it with us in the comments, if so, and we'll proceed to the Introduction section shortly.

 

 

Evid Based Complement Alternat Med. 2011; 2011: 381862.
Published online 2011 March 27. doi:  10.1155/2011/381862
PMCID: PMC3092553
Copyright © 2011 Deborah Bowden et al.
 
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
 
Articles from Evidence-based Complementary and Alternative Medicine : eCAM are provided here courtesy of Hindawi Publishing Corporation

Let's read together: A Randomised Controlled Single-Blind Trial of the Efficacy of Reiki at Benefitting Mood and Well-Being

Submitted by RST on Mon, 09/26/2011 - 09:26
Posted in

(UPDATE, 2 October 2011: link to the free fulltext PDF article is here; as well, the text of the article will be posted here at POEM for us to read through together, per their Creative Commons license. Cheers, to rchunco, for the improved suggestion!)

Let's go through this article together, sharing our insights along the way.

A Randomised Controlled Single-Blind Trial of the Efficacy of Reiki at Benefitting Mood and Well-Being

Deborah Bowden, Lorna Goddard, and John Gruzelier

Psychology Department, Goldsmiths, University of London, ITC Builidng[sic], New Cross, London SE14 6NW, UK

 

Abstract: This is a constructive replication of a previous trial conducted by Bowden et al. (2010), where students who had received Reiki demonstrated greater health and mood benefits than those who received no Reiki.

 

In the space of only one sentence in the abstract, a great deal of meaning is contained.

Let's save the first specialized term, "constructive replication", for last, as it is the most-complicated concept in the sentence.

The rest of the sentence is relatively straightforward.

The previous trial (or study) conducted by Bowden et al. (and others) is the following:

D. Bowden, L. Goddard, and J. Gruzelier, “A randomised controlled single-blind trial of the effects of Reiki and positive imagery on well-being and salivary cortisol,” Brain Research Bulletin, vol. 81, no. 1, pp. 66–72, 2010.

 

Unlike the study we're going through now, the 2010 article is behind a paywall, so I can't post it for reference. I can, however, quote relevant parts of it under the Fair Use provision, and so I'll do that as appropriate in discussing this article.

Bowden summarizes the results of the 2010 study as showing that "students who had received Reiki demonstrated greater health and mood benefits than those students who received no Reiki". This study is an attempt to replicate, or reproduce, those results.

Replication of studies has a long history in science. The entire point of an effect being universal, objective, and mind-independent (as opposed to unique, subjective, and mind-dependent) is for anyone to be able to reproduce the effect or outcome in question. Replication is how you demonstrate that anyone can do so.

It's also how you can ethically offer the possibility of specific outcomes to the client. No outcome is ever guaranteed, of course, but a reliably reproducible outcome at least holds the potential of your being able to deliver it to your client. If it can't be reliably reproduced, on the other hand, then how can you promise the client that there is a good chance that you will be able to deliver it?

For these reasons, replication studies are very important in scientific and clinical research in general, and specifically in massage research, as it can help us build our validated knowledge base.

"Constructive replication" is a very specific kind of replication, where researchers try to reproduce a study using methods that are different from the original study. At first, that may sound like a contradiction in terms, but it's actually a technique that has an established history in clinical research.

The primary reason that people carry out constructive replication is to try to demonstrate that--even when the study is carried out in a different way--the treatment is still associated with the desired results. It's like the cause-and-effect connection is so strong that it will come about one way or another; not just in the one way that was demonstrated in the previous study.

So what she's saying is that she's satisfied that the previous study validated the connection strongly enough that a constructive replication will expand and generalize the results from the ones in the first study.

We can add that to our list to check as we read through this one:

How methodologically sound was the 2010 study that this study is trying to generalize from?

 

The next sentence is straightforward:

The current study examined impact on anxiety/depression. 40 university students—half with high depression and/or anxiety and half with low depression and/or anxiety—were randomly assigned to receive Reiki or to a non-Reiki control group.

 

When we're reading the rest of the article, we'll look for an indication of how that number of 40 students was determined to have sufficient power for this study:

How was the number of 40 participants chosen, and what steps did the authors take to ensure that 40 participants made up a sufficiently-sized sample? 

 

The next sentence is somewhat unclear, although I expect the main article will clear up the ambiguity:

Participants experienced six 30-minute sessions over a period of two to eight weeks,

 

Does that mean some people got 6 sessions in 2 weeks, while others got 6 sessions in 8 weeks? That seems like a pretty wide variation in the treatment--such a large variation, in fact, that I would question whether or not we're comparing apples to oranges.

We'll look for a fuller explanation of this difference in the main article:

What is the actual discrepancy in timing of treatments, and what does this mean for the study?

 

The next note is totally one of style, not of substance, and doesn't affect the conclusions we'll draw from this article:

where they were blind

 

The correct word here is "blinded", rather than "blind". As mentioned, this won't affect our assessment of the article itself, but when you are writing research articles, you'll want to make sure you get that detail right.

 

to whether noncontact Reiki was administered as their attention was absorbed in a guided relaxation.

 

This sounds like a standard approach to providing a control for an intervention such as Reiki or massage.

 

The efficacy of the intervention was assessed pre-post intervention and at five-week follow-up by self-report measures of mood, illness symptoms, and sleep.

 

This looks fairly standard for testing for the capacity of the treatment to have an effect on the outcomes measures listed. We'll look at this in more detail in the Methods section.

 

The participants with high anxiety and/or depression who received Reiki showed a progressive improvement in overall mood, which was significantly better at five-week follow-up, while no change was seen in the controls.

 

Bowden is saying here that the students with either high anxiety, high depression, or both, showed an improvement in mood that continued to get better after the end of the study for the 5 weeks leading to the followup assessment. Additionally, she reports that this improvement is statistically significant, which means they've determined that the probability that this is a chance result, rather than a real treatment effect, is less than 5%, or 1 chance out of 20.

 

While the Reiki group did not demonstrate the comparatively greater reduction in symptoms of illness seen in our earlier study, the findings of both studies suggest that Reiki may benefit mood.

 

Bowden reports that the constructive replication did not show the same effects in the Reiki group with regard to reducing illness symptoms, but that both studies suggest that Reiki may benefit mood.

Notice her use of the word "suggest" and "may". This tentativeness is quite correct when drawing conclusions from a study. It is extremely rare to definitively determine cause and effect in this way; much more usual is the slow building of a solid body of evidence, which tends to point in one way or the other.

 

So that's what I've gotten our of the abstract. Did you get anything else from it?

Please share it with us in the comments, if so, and we'll proceed to the Introduction section shortly.

 

 

Evid Based Complement Alternat Med. 2011; 2011: 381862.
Published online 2011 March 27. doi:  10.1155/2011/381862
PMCID: PMC3092553
Copyright © 2011 Deborah Bowden et al.
 
This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
 
Articles from Evidence-based Complementary and Alternative Medicine : eCAM are provided here courtesy of Hindawi Publishing Corporation

Through the eyes of a scientist: Anatomical imagination and its constraints

Submitted by RST on Tue, 09/20/2011 - 11:55
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Imagination is more important than knowledge.

--Albert Einstein

Well, that kind of depends on the situation, doesn't it? But there's no denying that the combination of the two can be awesome!

When I teach anatomy, I walk a fine line with my students. Yes, they have to take a certification or licensing test at the end of their study, so if I haven't taken them up on Old Olympus' Towering Tops, (where) A Finn And German Viewed Some Hops, I have not done the part of my job which is to prepare them to take a multiple-choice examination to (we hope!) certify them as qualified to be admitted to practice.

But, as the end of the day, if facts and mnemonics and rote memorization are all that I've taught, then, as an educator, I have personally failed them. If they come away from my class thinking that anatomy is a vending machine--where you put in a predetermined question, and the machine dispenses exactly the same answer each time--then they will not be prepared for the myriad of variations that they will feel underneath their hands, when there are no teacher and no peers to consult with in the therapeutic moment.

So even more valuable than teaching facts is to teach them anatomical reasoning, or how to think systematically about what goes on in our bodies. They can always look up specific facts, like the names of the major blood vessels (except on the test, where they can't, so we do have to memorize some things). So if they can reason anatomically, and they know where to find high-quality anatomical facts, then the sky's the limit.

A big part of knowing how to reason anatomically is understanding how to use your imagination. But where, for artists, imagination not only can run free but is expected to, in science, imagination is constrained by the physical universe around us.

In his book, Quirks of Human Anatomy, Lewis Held provides a diagram that provides very useful guidance along these lines for channeling imagination in the service of anatomical reasoning.

 

 

His caption reads:

Figure 1.1. Real, possible, and conceivable subsets of vertebrate "Morphospace" in Venn diagram format.

 

I'll mention here that a Venn diagram shows relationships among things in each of the circles to each other. Since the white circle labeled "Reality" is completely enclosed in the gray circle labeled "Possibility", that means that everything that is real must also be possible--there is nothing that is simultaneously real and impossible.

Similarly, the gray "Possibility" circle is contained in the black "Conceivability" structure--there are things that we can conceive of that are not possible, but there is nothing that is the other way around.

 

The arrow points from the familiar to the fantastic.

 

He means implicitly, but does not make it clear, that "strangeness" increases as you travel from left to right along the arrow. We can't put a number on how strange something is--we can't say a Minotaur is 75% stranger than a normal bull, for example. But by saying that something is less strange (further left) or more strange (further right), we are actually measuring it, even without numbers.

 

City dwellers routinely see only a tiny part of the animal world: pets, birds, and the occasional squirrel.

 

That's why initiatives like this one, which connects children with nature, are so very important.

 

As children, we first met exotic animals (elephants, giraffes, etc.) at the zoo or circus and extinct dinosaurs at the museum. The thrill we felt at the novelty of those beasts has faded, but we can still get a similar frisson when we see science-fiction monsters in movie theaters.

Some of those fabulous creatures could have evolved if Earth's history had unfolded differently, whereas others could not, because they violate the laws of physics. For instance, centaurs could have evolved if the first fish to come on land had possessed three pairs of fins instead of two, as some other groups of fish did at that time.

Source: http://upload.wikimedia.org/wikipedia/commons/f/f5/Centaure_Malmaison_crop.jpg accessed 20 September 2011

 

The arms (forelimbs) and the legs (hindlimbs) of tetrapods (4-limbed animals with backbones, including us) evolved from the pectoral (chest) paired fins (labeled 10 in the following image) and the pelvic paired fins of bony fishes (labeled 9 in the following image).

Source: http://upload.wikimedia.org/wikipedia/commons/e/e3/Lampanyctodes_hectoris_%28Hector%27s_lanternfish%292.png accessed 20 September 2011

 

As you see in this artist's rendition of a centaur skeleton, there's an extra pair of forelimbs not accounted for in the fish skeleton. But if one of the other fishes who died out, the ones with 3 pairs of limbs, had made it onto land and led to the explosion of terrestrial vertebrates, then a centaur would have been a real possibility.

Source: http://upload.wikimedia.org/wikipedia/commons/7/78/Centaur_skeleton.jpg accessed 20 September 2011

 

"Historical constraints" are what divide the real from the possible--if history had played out differently, the three-pair-finned fish would have won out, and I'd be typing this post with my first set of two forelimbs. They represent other possibilities that--by chance or for other reasons--just didn't happen.

 

"Physical constraints" on the other hand--which separate the possible from everything else we can conceive of in our imaginations--can't play out any other way, because of the way our universe operates. The beings in the "Conceivable" black circle could not live or function in the physical universe we live in.

 

Examples of conceivable, but impossible, animals include (1) Steven Spielberg's E.T. (the Extra-Terrestrial), whose neck was too thin to support his cantilevered head, and (2) Walt Disney's Dumbo (the flying elephant) whose ears were too small (despite frantic flapping) to lift him into the air. The same is true for cherubs with their impotent wings. Mythical giants like Paul Bunyan could never stand, because their proportionately scaled legs would not support their overly massive torso, nor could Disney's pixies like Tinkerbell exist, because their brains would be too tiny to afford intellect. On the other hand, hobbits (~1 m tall à la Tolkien) not only could have evolved, but did, at least on one small island. Unicorns also evolved, albeit in aquatic form as narwhals, and, as noted by Aristotle, the Indian rhino is technically a unicorn as well, given its median nasal horn.

 

"Hobbit" is a nickname for Homo floriensis, a possible species of extinct hominin, fossils of whom have been found on the island of Flores in Indonesia. The nickname refers to its small stature, compared to modern humans.

 

 

Heavier- or lighter-gravity planets may have fostered a rich assortment of alien faunas, which we may someday encounter. Sadly, our Moon is lifeless, and although we like to think of it as colonizable, we are ill suited to walking there. Indeed, the Apollo astronauts resorted to hopping and skipping to get around.

 

 

On the Moon, we're too light to walk comfortably. At approximately 1/6th our weight on earth, hopping and skipping work better than trying to walk as we normally do.

A lot of things are possible, and imagination--working hand in hand with the constraints knowledge provides--can enable solid anatomical reasoning, a skill that serves MTs well in real life, when not every body on the table is a textbook case.

So, in light of anatomical reasoning, here's a question to consider:

If things had gone somewhat differently in our evolutionary history, could we--or animals related to us, like cats and dogs and squirrels and bears--have evolved wheels, instead of legs?

 

Why or why not, do you think? Let me know in the comments.

This isn't a test; it's just brainstorming, so don't be afraid to throw a guess out there, whether it's right or wrong.

No fair Googling, and if you already know the answer, why don't you hold back just a little bit and we'll all try to make our way to the same page.

I'll tell you the answer later, but right now, I'm much more interested in getting you into the process of thinking about it--imagining the possibilities, and then evaluating them in light of the knowledge you already have, and seeing where that takes you.

 

 

Foundational concepts: Bell curve/Normal distribution

Submitted by RST on Wed, 09/14/2011 - 13:32
Posted in

Recognition of the power of techniques making use of the naturally-occurring normal distribution (the bell curve) lies at the heart of some of the most useful and powerful methods in mathematics and science.

Click here to explore the concept of bell curve/normal distribution, which lies at the heart of so many of the statistics we use in massage research.

 

Foundational concepts: Bell curve/Normal distribution

Submitted by RST on Tue, 09/13/2011 - 09:19
Posted in

Why you may want to know this

The normal distribution is foundational knowledge for many statistics used in research, such as standard deviation, so understanding it opens the door to reading and understanding massage research articles that use those statistics.

As we often mention at POEM, words have power. The word "normal" can have strong connotations in everyday language, and can be used as implicit or explicit disapproval criticism against people who don't conform to norms of society.

In scientific usage, however, "normal" is not nearly so loaded a word. While it has the same denotations (dictionary meanings) of "typical, usual, or close to an average, according to a benchmark or standard", it doesn't carry any connotations (ideas) of positive or negative simply for being unusual.

What usual and unusual mean will vary, according to the situation. Generally, few people in the total population are extreme in many physical measurements; most are pretty close to a typical value in respect to most measurable physical qualities, which is what we'll deal with most as MTs. So, in that sense, most people are pretty "normal", and we'll remember to be aware of and sensitive to the needs of those who aren't.

For example, consider as a physical measurement the birth weight of all healthy babies born at term in the developed world. In this group, there will be a few big babies, weighing 8½ (8.5) to 9 pounds or more. The baby on the left in the following picture, born in the UK, weighed 14 lb, 7 oz (14.44 lb) at birth.

 

Source: http://img.dailymail.co.uk/i/pix/2007/08_01/nicholson1NTI1008_468x650.jpg

 

There will also be a few small babies, who weigh 6 to 6½ (6.5) pounds or less.

Source: http://latimesblogs.latimes.com/.m/photos/uncategorized/2009/03/18/premie.jpg

 

Unless some sort of problem such as gestational diabetes or premature delivery occurs, most of these babies born at term in developed nations tend to weigh about 7 to 8½ (8.5) pounds.

Let's imagine that we are keeping track of the babies born in one small region, and that 10 babies are born, with the following birth weights:

 

Baby Birth weight (in pounds)
Baby 1 7.2
Baby 2 9.6
Baby 3 7.5
Baby 4 7.7
Baby 5 7.4
Baby 6 8.0
Baby 7 5.9
Baby 8 7.6
Baby 9 6.1
Baby 10 8.9

 

 

Let's graph the data from our (imaginary) observation of birth weights.

 

Number of babies in this group that weigh less than 5.5 lbs:  0

 

Number of babies in this group that weigh 5.5 lbs-6.9 lbs:     2

(Baby 7, Baby 9)

 

Number of babies in this group that weigh 7.0 lbs-8.4 lbs:     6

(Baby 1, Baby 3, Baby 4, Baby 5, Baby 6, Baby 8)

 

Number of babies in this group that weigh 8.5 lbs-9.9 lbs:     2

(Baby 2, Baby 10)

 

Number of babies in this group that weigh more than 10 lbs: 0

 

We'll make a column chart of this data, where the x-axis (horizontal) is the birth weight range in pounds, and the y-axis (vertical) is the number of babies with that birth weight.

 
 
There is a pattern emerging in that data--most of the babies' birth weights tend to be in the middle of the range--fewer babies are either extremely large or extremely small at birth.
 
 

 

 

This much larger sample of Norwegian births between the years 1992 and 1998 was graphed in the same way. The x-axis (horizontal) is still the birth weight range, and the y-axis (vertical) is the number of babies with that birth weight. Since Norway uses the metric system, however, they report their birth weight data in kilograms (kg), so the x-axis is labeled in kg, rather than in pounds.
 
To compare that data to ours, then, we need to know how to convert between kg and pounds.
1.0 kg =  2.2 lb
2.0 kg =  4.4 lb
2.3 kg =  5.0 lb
2.7 kg =  6.0 lb
3.0 kg =  6.6 lb
3.2 kg =  7.0 lb
3.6 kg =  8.0 lb
4.0 kg =  8.8 lb
4.1 kg =  9.0 lb
4.5 kg = 10.0 lb
5.0 kg = 11.0 lb
6.0 kg = 13.0 lb
 
 
 
Even though this dataset is very, very much larger than our 10 observations--several of these birth weights in the mid-range are represented by 30,000 babies or more--we still see the same pattern we saw in our data: lots of babies have a middle-of-the-road birth weight, and the more extreme (the further from average) the birthweight, the fewer babies who have that weight.
 
 
This is another graph of birth weights, generated by the National Institutes of Health in the United States. Like the Norwegian graph, the weights in the middle of the range represent 30,000 or more babies born with those weights.
 
On this graph, the x-axis represents weights in grams (gm here, although usually abbreviated g), so the numbers along the horizontal axis are 1000 times larger than the numbers on the Norwegian graph in kg. No matter what the concept or term that we call it by is, however (gram vs. kilogram vs. pound), the physical referent--how heavy the newborn is--remains constant.
 
There is a lot of extra information on this graph that we won't be using, so don't worry about anything that seems unclear at this point, such as what "Residual" may mean. I'm talking only about the gray columns and the blue curve drawn over it, although you may recognize mean from our previous discussion (available by clicking here), and you may also recognize SD as "standard deviation", a statistical measurement that we are now laying the ground for discussing.
 
 
 

 

 

The smooth curve drawn connecting the values of these columns is the bell curve, which gets its name from the perceived resemblance to the outline of a bell. A normal distribution of a characteristic in a defined population or group describes a bell curve when graphed in this way.

The relatively few very small and very large babies are the small quantities shown at the extreme left and right sides of the graph (forming the small “tail” at either end). The higher number of 7 to 8½ pound babies make up the big “bump” or curve at the center of the graph.

The awesome thing about the normal distribution is how often it occurs naturally. Remember that our first dataset was made up up imaginary values. I chose those values carefully, to set it up to lead us smoothly into the rest of the discussion.

However, the next two datasets were real, natural data--nothing imaginary required for them. The fact that this distribution is found so often in so many different situations in the natural world allows us to draw connections that we can develop new knowledge out of.

Since data values for many natural phenomena tend to form this normal distribution—with most of the numbers in the middle and a few extreme values at either end—when not subjected to some purposeful manipulation (such as a massage treatment), this effect can be used as a baseline for measuring the distribution of data after such a treatment to see whether it differs significantly from the way the data was distributed before the treatment.

Recognition of the power of this technique lies at the heart of some of the most useful and powerful methods in mathematics and science. And over in Journal Club, you can see from the following presentation slides how Moyer and his team use this as part of their method to determine whether or not massage significantly reduces cortisol (it doesn't).

 

 

Foundational concepts: Average: Arithmetic mean

Submitted by RST on Wed, 09/07/2011 - 15:47
Posted in

To continue going through a table of numbers pre- and post-intervention to understand what they mean, we're approaching it through some foundational concepts so that we're all on the same page about them. Once we've done that, we can bring that understanding back to the article in Journal Club.

Click here to explore the meaning of the columns labeled "M" in the table of data we're examining.

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