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. 2022 Sep 7;13(3):100620. doi: 10.1016/j.jaim.2022.100620

Table 1.

Summary of the relevant research/papers on the methodological issues with the yoga and meditation.

Author (year) Title of the study Methodology Findings Remarks
Vieten et al. (2018) [56] Future directions in meditation research: Recommendations for expanding the field of contemplative science. Design: cross-sectional
Aims: to investigate the prevalence of a wide range of experiences. n = 1120 meditators
Inclusion Criteria: current or past meditation practice
Outcome: MEQ30, Extraordinary experiences
  • Gender: 59% female

  • Average age of 47 ± 16

  • Comorbid psychiatric illness: 25% of participants

  • Majority of respondents report having had many of these anomalous & extraordinary experiences

  • These aspects of meditation could be crucial to practitioners' psychological & spiritual development

  • Could also serve as mediators/mechanisms for conferring benefits.

  • They can be subjected to rigorous scientific investigation

Munaz et al. (2017) [57] The importance of research literacy for yoga therapists. Design: perspective
  • Research literacy & evidence-informed practice are essential skills for yoga therapists.

  • They should be systematically included in yoga therapy programs.

  • Many yoga therapists have limited training in these skills, which negatively impacts inter-professional communication & advancement of yoga research

  • Should be introduced early in the course curriculayoga therapy programs

  • Include qualified faculty to teach these competencies

Van Dam NT (2018) [17] Mind The Hype: A Critical Evaluation and Prescriptive Agenda for Research on Mindfulness and Meditation Design: review mindfulness meditation Objectives: to highlight difficulties of defining
mindfulness, delineates scope of research into mindfulness practices, & illuminates crucial methodological issues for interpreting results from research of mindfulness
  • Various possible meanings of ‘mindfulness’ need to be clarified

  • Researchers must adopt nuanced, precisely focused, terminology for referring to various states/behaviours a/w mindfulness.

  • MBR must work on construct validity of the practice.

  • Sound methodology e.g., adequate outcome measures, good psychometric properties, trial registration would aid in research

  • MBI research needs to have uniform & better control; participants need to be sensitized about the potential ADRs with it.

  • Advances in contemplative neuroscience should explore mental processes & brain mechanisms of mindfulness practices & report them properly.

  • Greater research is required toward improving the rigor of methods used, coupled with the accuracy of news-media publicity & eliminating public misunderstandings aroused by past undue ‘Mindfulness Hype’

Davidson & Dahl (2017) [25] Outstanding Challenges in Scientific Research on Mindfulness and Meditation Design: commentary
  • Methodology issue with the operational definition of the MM or meditation is not unique to MBR but applied to other area of behavioral sciences as well.

  • Both self-report measures & implicit behavioral aspects need to be considered in MBR

  • Future research needs to expand their horizon to include other family of contemplative practices rather limiting to MBR

  • Mindfulness practices have been conceived for attaining a general wellbeing; their utility for various disorders need to be researched contextually

  • Greater research is required on the frequency, duration, & spacing of the mindfulness practices & how it can be piggybacked with ADLs for its wider dissemination

  • Power of mobile technology can be harnessed in both disseminating contemplative training & its assessment

  • These issues are germane to both basic & clinical research studies.

  • Also, it has important bearing on the future scientific investigation of mindfulness & meditation

Davidson & Kaszniak (2015) [26] Conceptual & Methodological Issues in Research on Mindfulness & Meditation. Design: review
  • State & trait effect of the MM & their interactions along with practitioner's personality & expectations, compliance with the practices must be studied as they are crucial determinants of efficacy

  • Many practices are subsumed under MM though the extent of practice differ

  • The experiential account of the practitioner can be strengthened by incorporating second & third persons' account

  • Challenges are also posed by research designs where double-blinding is not possible: active control, e.g., dual blinding, could evade this limitations.

  • Adequate description of the intervention, comparable control arm, credence of the instructors, & fidelity of intervention delivery need to be ensured.

  • Similarly, the question of measurability of the mindfulness, what can & cannot be inferred from self-report measures; & utility of contemplative neurosciences are essential.

  • Robust study design & data analyses are also crucial.

  • Mindfulness-based research is still in infancy

  • The methodological limitations can be overcome by robust study design.

  • Mindfulness-based intervention should be tested both for the clinical and non-clinical population with giving due consideration to its conceptual framework

Van Dam NT (2018) [58] Reiterated Concerns and Further Challenges for Mindfulness and Meditation Research: A Reply to Davidson and Dahl Design: commentary
  • Nascent Scientific Fields, incl. MBR, are especially susceptible to methodological Issues, thus initial findings, or mis-findings, can have huge long-term impacts.

  • Meditation can cause adverse S/E; even in a small subset of participants, it can matter a lot

  • Impact of MBIs on clinical population should be investigated more thoroughly, for former is not traditionally meant for medical conditions, but general well-being.

  • Assessing & establishing dose–response curves of the meditation is crucial

  • Its impact must be ascertained based on outcome (e.g., alleviation of anxiety, attaining wellbeing)

  • For mobile-based system to deliver MBIs & for their dissemination, much research is warranted to establish fidelity of intervention delivery, analyse participants characteristics, etc.

  • The use of MBIs, including its delivery, for various conditions need to be established under the background of certain unresolved methodological and impact issues.

Patwardhan AR (2017) [59] Aligning Yoga With Its Evolving Role in Health Care: Comments on Yoga Practice, Policy, Research Design: commentary
  • Yoga therapists need to calibrate their model of yoga by reducing emphasis on postures & increasing it on meditation & breathing exercises while dealing with clients with chronic health issues.

  • Yoga research should be more critical in evaluating yoga's fundamental framework & have reductionist approach.

  • Regulatory bodies must extricate injury prone postures from the practice for regulatory purposes, than regulate yoga summarily.

  • Insurers should pay for yoga akin to vaccination (paying for initial dose & then booster sessions), this would widen the coverage of yoga & prevent future ill health

  • There is certain practice, policy, & research related issues concerning yoga, hence, it should be promptly & adequately addressed for yoga to flourish and bring fruition to the population

Field T. (2016) [2] Yoga Research Review Design: review (Of empirical research, systematic reviews and metanalyses)
  • Overall, yoga has been more effective than control, including waitlist control, for several physical & psychological problems, although results are mixed when compared with other treatment arms e.g., exercise

  • Having established the benefits of yoga, conducting a research without active control group, thereby not maintaining research equipoise, raises ethical concerns.

  • Shorter sessions should be investigated for cost-effectiveness & for ensuring daily practice.

  • Multiple physical & physiological measures, particularly objective measures, need to be added to the self-report research protocols.

  • Potential underlying mechanisms of effectiveness of the yoga to be explored.

  • There is literature support for yoga as an effective strategy for several medical and psychological problems

  • Such interventions van be termed as yoga therapy

  • Such interventions van be termed as yoga therapy

Uebelacker et al. (2012) [60] Yoga for Depression and Anxiety: A Review of Published Research and Implications for Healthcare Providers Design: review
  • Preliminary evidence suggests the effectiveness of yoga for anxiety, depression, & PTSD.

  • With evidence being strongest for unipolar depression.

  • However, there are risks with engaging with yoga as well.

  • HCPs can play a crucial role in evaluating the safety & utility of community-based yoga class in patient population.

Jeter et al. (2015) [29] Yoga as a Therapeutic Intervention: A Bibliometric Analysis of Published Research Studies from 1967 to 2013. Design: bibliometric analysis of clinical trials based on yoga
  • A three-fold increase in yoga publications in the decade.

  • 45% are RCTs f/b controlled (18%) & uncontrolled trails (37%)

  • Top three disease conditions are mental health, CVDs, & respiratory disease.

  • Research suffers from the methodological limitations (e.g., insufficient sample size).

  • The research also suffers from publication biases with uncontrolled & poor quality studies getting published in traditional journals.

  • The use of yoga as a complementary Tt in clinical practice may lead to health benefits beyond traditional Tt alone.

  • Determining the suitability & content of yoga for a specific condition/patient poses challenge for evidence-based integrative medical practice

  • However, to effect changes in health care policy, greater high-quality, evidence-based research is required.

Cook-cottone et al. (2013) [61] Dosage as a critical variable in yoga therapy research. Design: perspective
  • Considerable variability exists about the optimum dosage/duration of yoga to be effective (range 4–32wks, median 8wks)

  • Until empirically meaningful dosages, incl. length & frequency of sessions & longitudinal duration of practice are found, clinical guidelines would be arbitrary

  • Home practice contributes substantially to the benefits of yoga practice, which often remains unaccounted

  • Therapeutic dosage is a critical component of yoga intervention research.

  • Empirically supported guidelines are required to establish best practices for research & to create clinical recommendations for effective use

Josipovic Z (2010) [22] Duality and nonduality in meditation research Design: commentary
  • There is a taxonomical concern with the classification of the meditation: FA, OM, & AT types

  • A dualistic & non-dualistic classification of meditation for cognitive neurosciences & research is more pragmatic, albeit with some research-related limitations.

  • A multidimensional construct involving targeted states of consciousness; duality to nonduality scale; stages of expertise; cognitive processes; & objects of meditation is better

  • There is an overlap among the different meditation types concerning EEG changes.

  • Hence, formers' utility in meditation categorization needs to be further studied

  • Expanding the current taxonomy of meditation and defining the characteristic neurophysiological signatures of various meditation

  • Categories are important issues in meditation research

Park et al. (2015) [62] Comparison groups in yoga research: a systematic review and critical evaluation of the literature Design: systematic review
  • n = 128 RCTs

  • 65 included only a passive control while 63 included at least one active comparator

  • Primary comparison groups: physical exercise (43%), meditation/relaxation (20%), & general education (16%)

  • Literature rarely provides the rationale for the choice of the a particular comparator

  • Notably, use of active controls in yoga research seems to be gradually increasing over time

  • Considering that yoga has been established as a potentially effective intervention, future research should endeavour having active control groups

  • Furthermore, care is needed to select a robust comparison conditions that help to identify the specific mechanisms underlying yoga's effects

Goyal et al. (2014) [3] Meditation Programs for Psychological Stress and Well-being: A Systematic Review and Meta-analysis Design: systematic review & Meta-analysis
  • n = 47 trials with 3515 participants

  • MM programs had moderate level of evidence for improving anxiety, depression, & pain at 8 weeks to 3–6 months.

  • Low evidence of improved stress/distress & mental health–related quality of life

  • No effect or insufficient evidence of any effect on positive mood, attention, substance use, eating habits, sleep, & weight

  • Meditation programs did not fare better than drugs, exercises, & other behaviour Therapy

  • Clinicians ought be prepared to convey their patients about the potential role of the meditation program could have in addressing their psychological stress.

  • Robust study designs are required to elucidate the impact of meditation programs in improving the positive dimensions of psychological health and measures of stress.

Sedlmeier et al. (2012) [16] The psychological effects of meditation: a meta-analysis Design: systematic review & Meta-analysis
  • Majority of the studies were excluded d/t methodological issues

  • Most studies were conducted without theoretical background

  • Mediation-based interventions had moderate effect sizes

  • Results were strongest (medium-large) for changes in emotionality & relationship problems, less strong (medium) for measures of attention, & weakest (small-medium) for cognitive measures.

  • A comprehensive understanding of why & how meditation works, prominence should be placed on the development of more accurate theories & measurement tools.

Awasthi B. (2013) [14] Issues and Perspectives in Meditation Research: In Search for a Definition Design: commentary
  • A wide array of techniques & methods are collectively termed as “meditation” with mixed and at times conflicting findings reported within the contemplative neurosciences

  • There is the lack of philosophical grounding for the neuroscience of meditation.

  • For instance, modern neurosciences considers it in light of mind-body dichotomy, however, traditional meditation ontology sees it as non-dual entity.

  • Lack of sound definition results in methodological limitations, including replication of the studies.

  • Also, results in non-elucidation of its mechanism of action for neuro-cognitive-behavioural changes.

  • Paying due attention to the contextual & inception of meditation traditions is vital

  • 1st person methodologies should be integrated with the 3rd person methodologies of neurosciences

  • Specific outcome measures should be assessed for the different phases & types of the meditation

  • An integration of traditional ontology, 1st person phenomenological accounts & neuroscientific findings will facilitate the development of more comprehensive models of the mind for neurocognitive research with the contemplative traditions.

Davidson RJ (2010) [15] Empirical explorations of mindfulness: Conceptual and methodological conundrums Design: commentary
  • The use of the term “mindfulness” has varied substantially across the articles, ranging being a state to trait to an independent variable

  • Measures of the mindfulness, duration, and adequate comparison group related issues have been the consistent methodological concerns

  • Additional research with focus on the potential targets within the emotion domain of contemplative practices is warranted

Larkey L. (2021) [40] Meditative Movement as a Category of Exercise: Implications for Research Design: review (on Meditative Movement e.g., Tai-chi, Qigong, etc.)
  • Relevant dimensions of Meditative Movement, e.g., frequency, duration, type of movement, degree of exertion, breathing type, etc. are recommended to be succinctly described & measured.

  • To consistently define the category across studies & illuminate how Meditative Movement may affect health outcomes in similar, & perhaps different, ways than conventional exercise.

  • As Meditative Movement is studied as a category of exercise, research may progress more efficiently to define the domains of physiological and psychological benefit

Lustyk et al. (2009) [37] Mindfulness meditation research: issues of participant screening, safety procedures, and researcher training Design: review
  • Mental health- followed by physical & spiritual health consequences are common S/E with MM.

  • Despite this, most research do not describe, or even consider them.

  • Research participants/patients should be thoroughly medically examined before enrolling in MBI

  • A cautious approach to using meditation in research is warranted in the face of the limited and

  • Preliminary nature of current evidence to maximize participant safety.

Grossman P. (2008) [41] On measuring mindfulness in psychosomatic and psychological research Design: commentary
  • Definition of mindfulness has been varied across the studies.

  • Denominator of “present-moment awareness of perceptible experience” might, at first consideration, seem feasible; but suffers from reductionism

  • The inventories used to measure mindfulness vary substantially, therefore, there is a poor correlation among them

  • The measuring instruments also suffer from semantic confusion

  • Valid & reliable instrument are lacking that would objectively measure the mindfulness.

  • Mindfulness inventories may be hampered by serious limitations of construct validity

  • Qualitative analysis of the experiences of the Buddhist & western practitioners of mindfulness & putative consequences (e.g., general wellbeing) of MM can assist in measuring the level of mindfulness

  • It must be appreciated that Buddhist & Western approaches to mind & body differ substantially, thus study of mindfulness- & based intervention should be understood in its traditional framework.

Travis et al. (2010) [21] Focused attention, open monitoring and automatic self-transcending: Categories to organize meditations from Vedic, Buddhist and Chinese traditions Study design:perspective
  • Each of the three meditation-categories-focused attention, open monitoring, & aut. self-transcending- represents practices with different degrees of attention control, subject/object relations, & different procedures

  • However, TM technique, the most researched of the aut. self-transcending procedures, is often placed under FA

  • These explicit differences between meditation techniques must be regarded when studying physiological patterns or clinical outcomes of meditation practices.

AT: autonomic transcendence, a/w: associated with, CVDs: cardiovascular disease, d/t: due to, EEG: electroencephalogram, FA: focused attention, HCPs: Healthcare providers, MBR: mindfulness-based research, med.: medium, MEQ30: Revised Mystical Experience Questionnaire, MM: mindfulness meditation, MBI: mindfulness-based interventions, OM: open monitoring, PTSD: post-traumatic stress disorders, RCTs: randomized controlled trials, S/E: side-effects, TM: transcendental Meditation Tt: treatment.