The Effects of Virtual Reality Nonphysical Mental Training on Balance Skills and Functional Near-Infrared Spectroscopy Activity in Healthy Adults

in Journal of Sport Rehabilitation
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Context: Athletic skills such as balance are considered physical skills. However, these skills may not just improve by physical training, but also by mental training. The purpose of this study was to investigate the effects of mental training programs on balance skills and hemodynamic responses of the prefrontal cortex. Design: Randomized controlled trial. Methods: Fifty-seven healthy adults (28 females, 29 males), aged between 18–25 years, participated in this study. Participants were randomly assigned to 3 groups: virtual reality mental training (VRMT) group, conventional mental training (CMT) group, and control group. The training program included action observation and motor imagery practices with balance exercise videos. The VRMT group trained with a VR head-mounted display, while the CMT group trained with a non-immersive computer screen, for 30 minutes, 3 days per week for 4 weeks. At baseline and after 4 weeks of training, balance was investigated with stabilometry and Star Excursion Balance Test (SEBT). Balance tests were performed with simultaneous functional near-infrared spectroscopy (fNIRS) imaging to measure prefrontal cortex oxygenation. Results: For the stabilometry test, at least 1 variable improved significantly in both VRMT and CMT groups but not in the control group. For SEBT, composite reach distance significantly increased in both VRMT and CMT groups but significantly decreased in the control group. For separate directional scores, reach distance was significantly increased in both mental training groups for nondominant leg posterolateral and posteromedial directions, and dominant leg posterolateral direction, while nondominant posteromedial score was significantly increased only in the VRMT group. Between-group comparisons showed that dominant leg posteromedial and posterolateral score improvements were significantly higher than control group for both mental training groups, while nondominant leg improvements were significantly higher than control group only for the VRMT group. The fNIRS oxyhemoglobin levels were not significantly changed during stabilometry tests. However, oxyhemoglobin levels significantly reduced only in the control group during SEBT. Conclusions: Our findings suggest that both mental training interventions can significantly improve balance test results. Additionally, VRMT may have some advantages over CMT. These findings are promising for the use of mental training in prevention and rehabilitation for special populations such as athletes and older adults.

Köyağasıoğlu is with the Department of Sports Medicine, Kayseri City Training and Research Hospital, Kayseri, Turkey. Özgürbüz is with the Department of Sports Medicine, Faculty of Medicine, Ege University, İzmir, Turkey. Bediz is with the Department of Physiology, Kyrenia University Medical School, Kyrenia, Northern Cyprus. Bediz and Güdücü are with the Department of Biophysics, Dokuz Eylul University, Faculty of Medicine, İzmir, Turkey. Aydınoğlu and Akşit are with the Department of Coaching Education, Ege University, Faculty of Sport Sciences, İzmir, Turkey.

Köyağasıoğlu (ogunkoyagasioglu@gmail.com) is corresponding author.

Supplementary Materials

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  • 1.

    Zech A, Hübscher M, Vogt L, Banzer W, Hänsel F, Pfeifer K. Balance training for neuromuscular control and performance enhancement: a systematic review. J Athl Train. 2010;45(4):392403. PubMed ID: 20617915 doi:10.4085/1062-6050-45.4.392

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2.

    Hrysomallis C. Relationship between balance ability, training and sports injury risk. Sport Med. 2007;37(6):547556. doi:10.2165/00007256-200737060-00007

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 3.

    Thomas E, Battaglia G, Patti A, et al. Physical activity programs for balance and fall prevention in elderly. Med. 2019;98(27):19. doi:10.1097/MD.0000000000016218

    • Search Google Scholar
    • Export Citation
  • 4.

    Riemann BL, Lephart SM. The sensorimotor system, Part I: the physiologic basis of functional joint stability. J Athl Train. 2002;37(1):7179. PubMed ID: 16558670

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5.

    Nicholson V, Watts N, Chani Y, Keogh JW. Motor imagery training improves balance and mobility outcomes in older adults: a systematic review. J Physiother. 2019;65(4):200207. PubMed ID: 31521556 doi:10.1016/j.jphys.2019.08.007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6.

    Patel M. Action observation in the modification of postural sway and gait: theory and use in rehabilitation. Gait Posture. 2017;58:115120. PubMed ID: 28772130 doi:10.1016/j.gaitpost.2017.07.113

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7.

    Jeannerod M. Neural simulation of action: a unifying mechanism for motor cognition. Neuroimage. 2001;14(1, pt 2):103109. doi:10.1006/nimg.2001.0832

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 8.

    Taube W, Lorch M, Zeiter S, Keller M. Non-physical practice improves task performance in an unstable, perturbed environment: motor imagery and observational balance training. Front Hum Neurosci. 2014;8:110. doi:10.3389/fnhum.2014.00972

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 9.

    Gatti R, Sarasso E, Pelachin M, Agosta F, Filippi M, Tettamanti A. Can action observation modulate balance performance in healthy subjects? Arch Physiother. 2019;9:1. PubMed ID: 30693101

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10.

    Battaglia C, Artibale ED, Fiorilli G, et al. Use of video observation and motor imagery on jumping performance in national rhythmic gymnastics athletes. Hum Mov Sci. 2014;38:225234. PubMed ID: 25457420 doi:10.1016/j.humov.2014.10.001

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11.

    Johnson P. The functional equivalence of imagery and movement. Q J Exp Psychol Sect A. 1982;34(3):349365. doi:10.1080/14640748208400848

  • 12.

    Holmes PS, Collins DJ. The PETTLEP approach to motor imagery: a functional equivalence model for sport psychologists. J Appl Sport Psychol. 2001;13(1):6068.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 13.

    Ste-Marie DM, Law B, Rymal AM, Jenny O, Hall C, Mccullagh P. Observation interventions for motor skill learning and performance: an applied model for the use of observation. Int Rev Sport Exerc Psychol. 2012;5(2):3741. doi:10.1080/1750984X.2012.665076

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 14.

    Michalski SC, Szpak A, Loetscher T. Using virtual environments to improve real-world motor skills in sports: a systematic review. Front Psychol. 2019;10:19. doi:10.3389/fpsyg.2019.02159

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 15.

    Slater M, Khanna P, Mortensen J, Yu I. Visual realism enhances realistic response in an immersive virtual environment. IEEE Comput Soc. 2009;29(3):7684.

    • Search Google Scholar
    • Export Citation
  • 16.

    Vernadakis N, Derri V, Tsitskari E, Antoniou P. The effect of Xbox Kinect intervention on balance ability for previously injured young competitive male athletes: a preliminary study. Phys Ther Sport. 2014;15(3):148155. PubMed ID: 24239167 doi:10.1016/j.ptsp.2013.08.004

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17.

    Vogt S, Skjæret-Maroni N, Neuhaus D, Baumeister J. Virtual reality interventions for balance prevention and rehabilitation after musculoskeletal lower limb impairments in young up to middle-aged adults: a comprehensive review on used technology, balance outcome measures and observed effects. Int J Med Inform. 2019;126:4658. PubMed ID: 31029263 doi:10.1016/j.ijmedinf.2019.03.009

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18.

    Akbaş A, Marszałek W, Kamieniarz A, Jacek P, Kajetan JS, Juras G. Application of virtual reality in competitive athletes—a review. J Hum Kinet. 2019;69:516. PubMed ID: 31666884 doi:10.2478/hukin

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19.

    Cano Porras D, Sharon H, Inzelberg R, Ziv-Ner Y, Zeilig G, Plotnik M. Advanced virtual reality-based rehabilitation of balance and gait in clinical practice. Ther Adv Chronic Dis. 2019;10:204062231986837. doi:10.1177/2040622319868379

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 20.

    Muhanna MA. Virtual reality and the CAVE: taxonomy, interaction challenges and research directions. J King Saud Univ—Comput Inf Sci. 2015;27(3):344361. doi:10.1016/j.jksuci.2014.03.023

    • Search Google Scholar
    • Export Citation
  • 21.

    Bird JM. The use of virtual reality head-mounted displays within applied sport psychology. J Sport Psychol Action. 2020;11(2):115128. doi:10.1080/21520704.2018.1563573

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 22.

    Barros HO, Soares M, Epitácio L, Filho R. Use of virtual reality in neurorehabilitation: how the effects of immersion and presence may contribute to motor and cognitive. In: Rebelo MS, ed. Advances in Ergonomics In Design, Usability & Special Populations Part I. 1st ed. HFE Conference. 2014. doi:10.13140/2.1.3626.4321

    • Search Google Scholar
    • Export Citation
  • 23.

    Donath L, Rössler R, Faude O. Effects of virtual reality training (exergaming) compared to alternative exercise training and passive control on standing balance and functional mobility in healthy community-dwelling seniors: a meta-analytical review. Sport Med. 2016;46(9):12931309. doi:10.1007/s40279-016-0485-1

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 24.

    Kim KJ, Jun HJ. Effects of virtual reality programs on proprioception and instability of functional ankle instability. J Int Acad Phys Ther Res. 2015;6(2):891895. doi:10.5854/jiaptr.2015.10.30.891

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 25.

    Tanaka K, Parker JR, Baradoy G, Sheehan D, Holash JR, Katz L. A comparison of exergaming interfaces for use in rehabilitation programs and research. Loading..... 2012 Feb 1;6(9).

    • Search Google Scholar
    • Export Citation
  • 26.

    Schmidt RA, Lee TD, Winstein C, Wulf G, Zelaznik HN. Motor Control and Learning: A Behavioral Emphasis. Champaign, IL: Human Kinetics; 2018.

    • Search Google Scholar
    • Export Citation
  • 27.

    Taylor JA, Krakauer JW, Ivry RB. Explicit and implicit contributions to learning in a sensorimotor adaptation task. J Neurosci. 2014;34(8):30233032. PubMed ID: 24553942 doi:10.1523/JNEUROSCI.3619-13.2014

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 28.

    Fitts PM, Posner MI. Human Performance. Belmont, CA: Brooks/Cole Publishing Company; 1967.

  • 29.

    Miller EK, Cohen JD. An integrative theory of prefrontal cortex function. Annu Rev Neurosci. 2001;24:167202. PubMed ID: 11283309

  • 30.

    Sanes JN. Neocortical mechanisms in motor learning. Curr Opin Neurobiol. 2003;13:225231. PubMed ID: 12744978 doi:10.1016/S0959-4388(03)00046-1

  • 31.

    Basso Moro S, Bisconti S, Muthalib M, et al. A semi-immersive virtual reality incremental swing balance task activates prefrontal cortex: a functional near-infrared spectroscopy study. Neuroimage. 2014;85:451460. PubMed ID: 23684867 doi:10.1016/j.neuroimage.2013.05.031

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 32.

    Gentili R, Han CE, Schweighofer N, Papaxanthis C. Motor learning without doing: trial-by-trial improvement in motor performance during mental training. J Neurophysiol. 2010;104(2):774783. PubMed ID: 20538766 doi:10.1152/jn.00257.2010

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 33.

    Puttemans V, Wenderoth N, Swinnen SP. Changes in brain activation during the acquisition of a multifrequency bimanual coordination task: from the cognitive stage to advanced levels of automaticity. J Neurosci. 2005;25(17):42704278. PubMed ID: 15858053 doi:10.1523/JNEUROSCI.3866-04.2005

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 34.

    Hrysomallis C. Balance ability and athletic performance. Sport Med. 2011;41(3):221232.

  • 35.

    Irani F, Platek SM, Bunce S, Ruocco AC, Chute D. Functional near infrared spectroscopy (fNIRS): an emerging neuroimaging technology with important applications for the study of brain disorders. Clin Neuropsychol. 2007;21(1):937. PubMed ID: 17366276 doi:10.1080/13854040600910018

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 36.

    Mihara M, Miyai I, Hatakenaka M, Kubota K, Sakoda S. Role of the prefrontal cortex in human balance control. Neuroimage. 2008;43(2):329336. PubMed ID: 18718542 doi:10.1016/j.neuroimage.2008.07.029

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 37.

    Wriessnegger SC, Kurzmann J, Neuper C. Spatio-temporal differences in brain oxygenation between movement execution and imagery: a multichannel near-infrared spectroscopy study. Int J Psychophysiol. 2008;67(1):5463. PubMed ID: 18006099 doi:10.1016/j.ijpsycho.2007.10.004

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 38.

    Holper L, Wolf M. Motor imagery in response to fake feedback measured by functional near-infrared spectroscopy. Neuroimage. 2010;50(1):190197. PubMed ID: 20026278 doi:10.1016/j.neuroimage.2009.12.055

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 39.

    Mouthon A, Ruffieux J, Mouthon M, Hoogewoud H, Annoni J, Taube W. Age-related differences in cortical and subcortical activities during observation and motor imagery of dynamic postural tasks: an fMRI study. Neural Plast. 2018;2018:1598178. PubMed ID: 29675037

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 40.

    Oldfield RC. The assessment and analysis of handedness: the Edinburgh inventory. Neuropsychologia. 1971;9(1):97113. PubMed ID: 5146491 doi:10.1016/0028-3932(71)90067-4

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 41.

    van Melick N, Meddeler BM, Hoogeboom TJ, Nijhuis-van der Sanden MWG, van Cingel REH. How to determine leg dominance: the agreement between self-reported and observed performance in healthy adults. PLoS One. 2017;12(12):19. doi:10.1371/journal.pone.0189876

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 42.

    Roberts R, Callow N, Hardy L, Markland D, Bringer J. Movement imagery ability: development and assessment of a revised version of the vividness of movement imagery questionnaire. J Sport Exerc Psychol. 2008;30(2):200221. PubMed ID: 18490791 doi:10.1123/jsep.30.2.200

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 43.

    Kennedy RS, Lane NE, Kevin S, Lilienthal MG. The international journal of aviation psychology simulator sickness questionnaire: an enhanced method for quantifying simulator sickness. Int J Aviat Psychol. 1993;3(3):203220. doi:10.1207/s15327108ijap0303

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 44.

    Davlin CD. Dynamic balance in high level athletes. Percept Mot Skills. 2004;98:11711176. PubMed ID: 15291203

  • 45.

    Rohbanfard H, Proteau L. Learning through observation: a combination of expert and novice models favors learning. Exp Brain Res. 2011;215:183197. PubMed ID: 21986667 doi:10.1007/s00221-011-2882-x

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 46.

    Rizzolatti G, Cattaneo L, Fabbri-Destro M, Rozzi S. Cortical mechanisms underlying the organization of goal-directed actions and mirror neuron-based action understanding. Physiol Rev. 2014;94(2):655706. PubMed ID: 24692357 doi:10.1152/physrev.00009.2013

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 47.

    Mauch M, Kälin X. Reliability of the ProKin Type B line system (TechnoBody™) balance system (Internal Project Report). Praxisklinik Rennbahn AG;2011: 19.

    • Search Google Scholar
    • Export Citation
  • 48.

    Robinson RH, Gribble PA. Support for a reduction in the number of trials needed for the star excursion balance test. Arch Phys Med Rehabil. 2008;89:364370. PubMed ID: 18226664 doi:10.1016/j.apmr.2007.08.139

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 49.

    Ayaz H, Shewokis PA, Curtin A, Izzetoglu M, Izzetoglu K, Onaral B. Using MazeSuite and functional near infrared spectroscopy to study learning in spatial navigation. J Vis Exp. 2011;(56):113. doi:10.3791/3443

    • Search Google Scholar
    • Export Citation
  • 50.

    Ayaz H, Izzetoglu M, Shewokis PA, Onaral B. Sliding-window motion artifact rejection for Functional Near-Infrared Spectroscopy. Annu Int Conf IEEE Eng Med Biol Soc. 2010;2010:65676570. PubMed ID: 21096508

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 51.

    Noguchi K, Gel YR, Brunner E, Konietschke F. nparLD: an R software package for the nonparametric analysis of longitudinal data in factorial experiments. J Stat Softw. 2012;50(12):123.

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 52.

    Jancová J. Measuring the balance control system. Acta Medica. 2008;51(3):129137. PubMed ID: 19271679 doi:10.14712/18059694.2017.14

  • 53.

    Gill J, Allum JHJ, Carpenter MG, et al. Trunk sway measures of postural stability during clinical balance tests: effects of age. J Gerontol: Ser A Biol Sci Med Sci. 2001;56(7):438447. doi:10.1093/gerona/56.7.M438

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 54.

    Latash M, Levin M, Scholz J, Schöner G. Motor control theories and their applications. Medicina. 2010;46(6):382. PubMed ID: 20944446 doi:10.3390/medicina46060054

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 55.

    Ting LH. Dimensional reduction in sensorimotor systems: a framework for understanding muscle coordination of posture. Prog Brain Res. 2007;165:299321. PubMed ID: 17925254 doi:10.1016/S0079-6123(06)65019-X

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 56.

    Milovan B. Motor learning in sport. Facta Univ Phys Educ Sport. 2004;2:4559.

  • 57.

    Zemková E. Assessment of balance in sport: science and reality. Serbian J Sport Sci. 2011;5:127139.

  • 58.

    Lin D, Seol H, Nussbaum MA, Madigan ML. Reliability of COP-based postural sway measures and age-related differences. Gait Posture. 2008;28(28):337342. doi:10.1016/j.gaitpost.2008.01.005

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 59.

    Powden CJ, Dodds TK, Gabriel EH. The reliability of the star excursion balance test and lower quarter Y-balance test in healthy adults: a systematic review. Int J Sports Phys Ther. 2019;14(5):683694. PubMed ID: 31598406 doi:10.26603/ijspt20190683

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 60.

    Sims J, Cosby N, Saliba EN, Hertel J, Saliba SA. Exergaming and static postural control in individuals with a history of lower limb injury. J Athl Train. 2013;48(3):314325. PubMed ID: 23675790 doi:10.4085/1062-6050-48.2.04

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 61.

    Gribble PA, Hertel J, Plisky P. Using the star excursion balance test to assess dynamic postural-control deficits and outcomes in lower extremity injury: a literature and systematic review. J Athl Train. 2012;47(3):339357. PubMed ID: 22892416 doi:10.4085/1062-6050-47.3.08

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 62.

    Bhatt T, Pai YC. Can observational training substitute motor training in preventing backward balance loss after an unexpected slip during walking? J Neurophysiol. 2007;99(2):843852. PubMed ID: 18003882 doi:10.1152/jn.00720.2007

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 63.

    Dayan E, Cohen LG. Neuroplasticity subserving motor skill learning. Neuron. 2011;72(3):443454. PubMed ID: 22078504 doi:10.1016/j.neuron.2011.10.008

  • 64.

    Doyon J, Penhune V, Ungerleider LG. Distinct contribution of the cortico-striatal and cortico-cerebellar systems to motor skill learning. Neuropsychologia. 2003;41:252262. PubMed ID: 12457751

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 65.

    Wolpert DM, Diedrichsen J, Flanagan JR. Principles of sensorimotor learning. Nat Rev Neurosci. 2011;12(12):739751. PubMed ID: 22033537 doi:10.1038/nrn3112

  • 66.

    Munzert J, Zentgraf K, Stark R, Vaitl D. Neural activation in cognitive motor processes: comparing motor imagery and observation of gymnastic movements. Exp Brain Res. 2008;188(3):437444. PubMed ID: 18425505 doi:10.1007/s00221-008-1376-y

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 67.

    Vogt S, Eaves DL, Scott M, Taylor S, Chesterton P. Motor imagery during action observation increases eccentric hamstring force: an acute non-physical intervention. Disabil Rehabil. 2017;40(12):14431451. doi:10.1080/09638288.2017.1300333

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 68.

    Lawrence G, Callow N, Roberts R. Watch me if you can: imagery ability moderates observational learning effectiveness. Front Hum Neurosci. 2013;7:17. doi:10.3389/fnhum.2013.00522

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 69.

    Vandevoorde K, Orban De Xivry J-J. Why is the explicit component of motor adaptation limited in elderly adults? J Neurophysiol. 2020;124:152167. PubMed ID: 32459553 doi:10.1152/jn.00659.2019

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 70.

    Bedir D, Erhan SE. The effect of virtual reality technology on the ımagery skills and performance of target-based sports athletes. Front Psychol. 2021;11:2073. PubMed ID: 33551887 doi:10.3389/fpsyg.2020.02073

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 71.

    Smith D, Wakefield C. It’s all in the mind: PETTLEP-based imagery and sports performance. J Appl Sport Psychol. 2007;19:8092. doi:10.1080/10413200600944132

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 72.

    Shu Y, Huang YZ, Chang SH, Chen MY. Do virtual reality head-mounted displays make a difference? A comparison of presence and self-efficacy between head-mounted displays and desktop computer-facilitated virtual environments. Virtual Real. 2019;23(4):437446. doi:10.1007/s10055-018-0376-x

    • Crossref
    • Search Google Scholar
    • Export Citation
  • 73.

    Dhillon H, Dhillon S, Dhillon M. Current concepts in sports injury rehabilitation. Indian J Orthop. 2017;51(5):529536. PubMed ID: 28966376 doi:10.4103/ortho.IJOrtho

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
  • 74.

    Hoshi Y. Functional near-infrared spectroscopy: potential and limitations in neuroimaging studies. Int Rev Neurobiol. 2005;66(5):237266. doi:10.1016/S0074-7742(05)66008-4

    • Crossref
    • PubMed
    • Search Google Scholar
    • Export Citation
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