Abstract
The present study was undertaken to provide scientific evidence and for beneficial effects of vestibular stimulation for the management of stress-induced changes in auditory and visual reaction time (RT). A total of 240 healthy college students of the age group of 18–24 of either gender were a part of this research after obtaining written consent from them. RT for right and left response was measured for two auditory stimuli (low and high pitch) and visual stimuli (red and green) were recorded. A significant decrease in the visual RT for green light and red light was observed and stress-induced changes was effectively prevented followed by vestibular stimulation. Auditory RT for high pitch right and left response was significantly decreased and stress-induced changes was effectively prevented followed by vestibular stimulation. Vestibular stimulation is effective in boosting auditory and visual RT and preventing stress-induced changes in RT in males and females. We recommend incorporation of vestibular stimulation by swinging in our lifestyle for improving cognitive functions.
Key words: College students, response times, stress, swing, vestibular stimulation
INTRODUCTION
Reaction time (RT) is a simple and noninvasive test to assess central and peripheral neural structures.[1] RT is defined as the time interval between applications of a stimulus and elicitation of a response.[2,3] Earlier studies reported that excessive stress has a negative impact on cognitive functions and this negative impact was more profound in females than males.[4,5,6] Improvement in attention, motor speech parameters, RT was observed followed by vestibular stimulation in head injured patients.[7] Vestibular stimulation modulates the neuronal activity in the medullary cardiovascular areas through cerebellum, basal ganglia, and limbic system.[8] Interestingly, vestibular stimulation was found to boost the neurodegenerative brains.[8] Otolith and visual-vestibular stimulation was reported to interfere prominently on cognitive processing especially the spatial tasks.[9] Rotatory vestibular stimulation was reported to enhance the balance and eye-hand coordination.[10] The present study was undertaken to provide scientific evidence and for beneficial effects of vestibular stimulation for the management of stress-induced changes in auditory and visual RT.
MATERIALS AND METHODS
Study design
This was a longitudinal follow-up study in which, participants were assessed 3 times. The first assessment was performed during regular classes (with no examination in preceding 2 weeks and coming 2 weeks), these are baseline values. The second assessment was performed after intervention and during regular classes, and third assessment was performed in stressed state (1 week before University theory examinations).
Setting
The present study was conducted at Little Flower Institute of Medical Sciences and Research, Angamaly, affiliated to Kerala University of Health Sciences, Kerala and Little Flower Medical Research Centre, Angamaly, approved by Mahatma Gandhi University, Kerala.
Study population
A total of 240 healthy college students of the age group of 18–24 of either gender were a part of this research after obtaining written consent from them. Participants involved in drug/alcohol abuse, and those taking any kind of medication or suffering from any somatic or mental disorders, participants with a history of use of corticosteroids in the past year, students with a history of antidepressant medication, and students on hormone supplements including oral contraceptives and ear infections or any vestibular disturbances, visual disorders, those with cardio-respiratory disorders were excluded from this study. Selected participants were randomly assigned to four groups by simple random sampling. This study was powered at 0.85% to identify 15%-20% of improvement followed by vestibular stimulation.
Group MC (n = 60): Control male group (no vestibular stimulation was administered)
Group FC (n = 60): Control female group (no vestibular stimulation was administered)
Group MV (n = 60): Intervention male group (vestibular stimulation was administered for 268 ± 5 days)
Group FV (n = 60): Intervention female group (vestibular stimulation was administered for 268 ± 6 days).
After recording baseline values, vestibular stimulation was administered to the intervention groups and post-intervention values were collected during regular classes (duration of intervention was 146 ± 5.6 days in males and 147 ± 6 days in females) and during preexamination period (duration of intervention was 268 ± 5 days in males and 268 ± 6 days in females) followed by vestibular stimulation. Vestibular stimulation was not administered to the control group. However, values were recorded at the corresponding points in time.
Vestibular stimulation
Vestibular stimulation was administered by making the participants swing on a swing, according to their comfort (back to front direction) once in a day, for 5 days in a week at their leisure time (8:30–9:30 am, 11:00–12:00 am, 1:00–2:00 pm, and 4:00–5:00 pm in four groups) as described earlier.[11]
Assessment of Auditory and visual reaction time
RT apparatus for research, manufactured by Anand Agencies, Pune, was used to record auditory and visual RT. Anand Agencies (http://www.anandagenciespune.in). The apparatus has E side (examiner side), S side (subject side) and chronoscope. E side consists of switches for stimuli selection, selector switches to select desired response, fore period knob, start and reset switches and main switch. Four stimuli selection switches, which when pressed will latch and select the indicated stimulus, which will be automatically presented during the trial. Light emitting diode indicator was provided in front of each switch, which will glow and indicates the stimulus selected for the trial. Any and only one stimuli can be selected at a time. The apparatus provides two auditory (high and low pitch sounds) and two visual (red and green light). The arrangement was made to adjust the fore period at any desired value between 0.5 s and 5.5 s. The reset switch will reset the chronoscope and release the selected stimulus and makes the apparatus ready for the next trail. S side has red and green light mounted side by side which serve as stimuli. Speaker giving the auditory stimuli was mounted inside the apparatus. The chronoscope was built in to count the RT in milliseconds. S side was also equipped with two micro switches on either side which serves as subject's right and left response keys. The response was given by the subject by pressing a key with his index finger of corresponding hand. Time taken by the subject to give a response is displayed with an accuracy of 1 ms and is recorded as his auditory or visual RT.[12] Auditory and visual RT was recorded in a well-ventilated and noise free room in the Department of Physiology. The procedure was explained to all the participants, and they were made familiar with the apparatus. The location and direction of the RT apparatus and position of participant were maintained constant throughout the study period. The participant was allowed to relax before commencing with recording of RT. RT for right and left response was measured for two auditory stimuli (low and high pitch) and visual stimuli (red and green) and the sequence of application of stimuli was kept constant. The Procedure was explained to all the subjects individually. While recording the RT for each stimulus, after pressing the start switch, a “ready” or warning signal was given for a fixed period. The stimuli were then automatically presented after the preset fore period. The test subject was asked to press the button as soon as he received the stimulus. Emphasis was given on how quickly the response was obtained and the subject was instructed accordingly. Three readings of the RT were taken for each stimulus by randomly varying the fore period. The lowest value of three readings was considered as RT for that stimulus.
Ethics
The study was approved by Institutional Ethics Committee (January 10, 2014) of Little Flower Hospital and Research Center. A written, informed consent was obtained from all the participants. The study was performed in accordance with the “Ethical Guidelines for Biomedical Research on Human Participants, 2006” by the Indian Council of Medical Research and the Declaration of Helsinki, 2008.
Data analysis
Data were analyzed by IBM SPSS Statistics for Windows, IBM Corp., Armonk, NY. Mean and standard deviations of all the observations were calculated. Comparison between the groups was performed by two way ANOVA and post hoc by Bonferroni posttest. Statistical significance was accepted at P < 0.05.
RESULTS
Baseline values of both right and left responses of visual RT for green light were significantly higher in females than males. Stress-induced increase in visual and auditory RT (ART) (both right and left responses) was significantly higher in females [Figures 1 and 2]. Significant decrease in the visual RT for green light and red light was observed and stress-induced changes was effectively prevented followed by vestibular stimulation [Figure 1]. ART for high pitch right and left response was significantly decreased and stress-induced changes was effectively prevented followed by vestibular stimulation [Figure 2].
Figure 1.
Visual reaction time (VRT) (ms) of the participants before and after vestibular stimulation. (Data expressed are mean ± standard deviation) (*P < 0.05, **P < 0.01, ***P < 0.001), MV: Vestibular males, FV: Vestibular females, MC: Control males, FC: Control females. D0: Preintervention score (during regular classes), D1: Postintervention score (during regular classes), D2: Postintervention scores (during preexamination period). Rt: Right response, Lt: Left response
Figure 2.
Auditory reaction time (ms) of the participants before and after vestibular stimulation. (Data expressed are mean ± standard deviation) (*P < 0.05, **P < 0.01, ***P < 0.001), MV: Vestibular males, FV: Vestibular females, MC: Control males, FC: Control females. D0: Preintervention score (during regular classes), D1: Postintervention score (during regular classes), D2: Postintervention scores (during preexamination period). Rt: Right response, Lt: Left response
DISCUSSION
Stress affects cognitive function via epinephrine cortisol.[4] According to the distraction model, anxiety decreases accuracy of the movements execution so that the subject requires more attempts or more time to complete a task successfully.[13,14] Stress increases the load on the cognitive system and reduces a person's attention.[15] In contrast, according to the execution focus model, negative effects of anxiety on performance cannot be explained with limited attention resources.[16] Malathi and Parulkar reported that ART was decreased before examinations.[17] In the present study, we have observed a significant increase in the auditory and visual RTs in pre-examination period in both male and female control groups. However, this stress-induced change was effectively prevented in the intervention groups. This effect may be due to decrease in the cortisol and autonomic modulation by vestibular stimulation.[18,19,20] RT was related to cognitive function in healthy subjects and patients and serve as bedside measurements reflecting, cognitive function.[21] RT comprises of three parts that are perception time, decision time, and motor time.[22,23] Vestibular stimulation causes optimal arousal and decrease the RT.[10] Vestibular disorders causes a high level of alertness and vigilance, problems maintaining focus, problems paying selective attention, and alterations in precision and attention to stimuli.[24] Vestibular stimulation modulates somatosensory processing increases tactile sensitivity on the fingers of both hands.[25,26,27,28,29] Vestibular stimulation influences decision-making by modulating emotional circuits and pleasant and rewarding effect of acquisition.[30] Vestibulospinal reflexes maintain the coordination between anterior and posterior muscles and controls the timing and intensity of muscle contractions.[31] Vestibular stimulation modulates executive function through its connections with cortical and subcortical structures.[32] Vestibular exercises with head and body movements recommended for individuals with visual impairments for better balance retention.[33,34,35,36] Vestibular stimulation was reported to activate intraparietal sulcus, the parietal–temporal junction and central sulcus, the superior temporal gyrus and insula, ventral premotor areas, cingulate gyrus, and hippocampus.[37] Our results are in accordance with earlier research reports as we have observed significant decrease in the visual RT for red and green light (both right and left responses) and ART for high pitch and low pitch sound (both right and left responses) followed by vestibular stimulation in males and females. Vestibular stimulation effectively prevented stress-induced changes in visual and ART in males and females.
Limitations
We could not exclude the effect of movement activity and norepinephrine release on the evaluated indices, as we have no suitable control group for this purpose. Hence, the findings from this study should be interpreted considering these limitations.
CONCLUSION
Vestibular stimulation is effective in boosting auditory and visual RT and preventing stress-induced changes in RT in males and females. We recommend incorporation of vestibular stimulation by swinging in our lifestyle for improving cognitive functions.
Financial support and sponsorship
Nil.
Conflicts of interest
There are no conflicts of interest.
Acknowledgment
Our sincere thanks to Anand Agencies 1433/A, Shukrawar Peth, Tulpule Wada, Off Bajirao Road, Pune - 411 002, for sponsoring Research RT apparatus for the study. Special thanks to Mr. Prakash Raghunath Tulpule is a partner of “Anand Agencies” for his support and encouragement. The abstract was presented as oral presentation at the 1st KUHS National Conference on Post Graduate Medical Research 2016 (THRICON16) on October 6 and 7, 2016 held at Government Medical College, Thrissur, Kerala, India.
REFERENCES
- 1.Mohan M, Thombre DP, Das AK, Subramanian N, Chandrasekar S. Reaction time in clinical diabetes mellitus. Indian J Physiol Pharmacol. 1984;28:311–4. [PubMed] [Google Scholar]
- 2.Kamble JP, Deshpande VK, Phatak MS. The study of auditory and visual reaction times in chronic smokers. Int J Med Health Sci. 2013;2:18–22. [Google Scholar]
- 3.Solanki J, Joshi N, Shah C, Mehta HB, Gokhle PA. Study of correlation between auditory and visual reaction time in healthy adults. Int J Med Public Health. 2012;2:36–8. [Google Scholar]
- 4.Ruprai RK, Kamble P, Kurwale M. Environmental stress and changes in a anxiety score and reaction time: A comparative study among day scholars and hostilities in first year MBBS students. Glob J Interdiscip Soc Sci. 2012;1:1–3. [Google Scholar]
- 5.Luine V, Villegas M, Martinez C, McEwen BS. Repeated stress causes reversible impairments of spatial memory performance. Brain Res. 1994;639:167–70. doi: 10.1016/0006-8993(94)91778-7. [DOI] [PubMed] [Google Scholar]
- 6.Gerges NZ, Alzoubi KH, Park CR, Diamond DM, Alkadhi KA. Adverse effect of the combination of hypothyroidism and chronic psychosocial stress on hippocampus-dependent memory in rats. Behav Brain Res. 2004;155:77–84. doi: 10.1016/j.bbr.2004.04.003. [DOI] [PubMed] [Google Scholar]
- 7.Engberg A. Vestibular stimulation after head injury: Effect on reaction times and motor speech parameters. Arch Phys Med Rehabil. 1989;70:893–901. [PubMed] [Google Scholar]
- 8.Yamamoto Y, Struzik ZR, Soma R, Ohashi K, Kwak S. Noisy vestibular stimulation improves autonomic and motor responsiveness in central neurodegenerative disorders. Ann Neurol. 2005;58:175–81. doi: 10.1002/ana.20574. [DOI] [PubMed] [Google Scholar]
- 9.Furman JM, Redfern MS, Fuhrman SI, Jennings JR. Visual-vestibular stimulation influences spatial and non-spatial cognitive processing. J Vestib Res. 2012;22:253–9. doi: 10.3233/VES-2012-00460. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Tsang WW, Fong SS, Cheng YT, Daswani DD, Lau HY, Lun CK, et al. The effect of vestibular stimulation on eye-hand coordination and postural control in elite basketball players. Am J Sports Sci. 2014;2:17–22. [Google Scholar]
- 11.Sailesh KS, Mukkadan JK. Controlled vestibular stimulation, standardization of a physiological method to release stress in college students. Indian J Physiol Pharmacol. 2015;59:436–41. [PubMed] [Google Scholar]
- 12.Vallath AL, Joshi AR, Vaidya SM. Effect of abstinence on audio-visual reaction time in chronic smokers pursuing a professional course. J Clin Diagn Res. 2015;9:CC08–11. doi: 10.7860/JCDR/2015/14696.6973. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Eysenck MW, Derakshan N, Santos R, Calvo MG. Anxiety and cognitive performance: Attentional control theory. Emotion. 2007;7:336–53. doi: 10.1037/1528-3542.7.2.336. [DOI] [PubMed] [Google Scholar]
- 14.Behan M, Wilson M. State anxiety and visual attention: The role of the quiet eye period in aiming to a far target. J Sports Sci. 2008;26:207–15. doi: 10.1080/02640410701446919. [DOI] [PubMed] [Google Scholar]
- 15.Chajut E, Algom D. Selective attention improves under stress: Implications for theories of social cognition. J Pers Soc Psychol. 2003;85:231–48. doi: 10.1037/0022-3514.85.2.231. [DOI] [PubMed] [Google Scholar]
- 16.Beilock SL, Carr TH. On the fragility of skilled performance: What governs choking under pressure? J Exp Psychol Gen. 2001;130:701–25. [PubMed] [Google Scholar]
- 17.Malathi A, Parulkar VG. Evaluation of anxiety status in medical students prior to examination stress. Indian J Physiol Pharmacol. 1992;36:121–2. [PubMed] [Google Scholar]
- 18.Smitha KK, Dinesh KS, Mukkadan JK. Standardisation of controlled vestibular stimulation for optimal stress relief in albino wistar rats. Pharma Innov J. 2015;4:1–3. [Google Scholar]
- 19.Furman JM, Jacob RG, Redfern MS. Clinical evidence that the vestibular system participates in autonomic control. J Vestib Res. 1998;8:27–34. [PubMed] [Google Scholar]
- 20.Winter L, Kruger TH, Laurens J, Engler H, Schedlowski M, Straumann D, et al. Vestibular stimulation on a motion-simulator impacts on mood states. Front Psychol. 2012;3:499. doi: 10.3389/fpsyg.2012.00499. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 21.Jakobsen LH, Sorensen JM, Rask IK, Jensen BS, Kondrup J. Validation of reaction time as a measure of cognitive function and quality of life in healthy subjects and patients. Nutrition. 2011;27:561–70. doi: 10.1016/j.nut.2010.08.003. [DOI] [PubMed] [Google Scholar]
- 22.Teichner WH. Recent studies of simple reaction time. Psychol Bull. 1954;51:128–49. doi: 10.1037/h0060900. [DOI] [PubMed] [Google Scholar]
- 23.Tripo RS. How fast can you react? Sci Dig. 1965;57:50. [Google Scholar]
- 24.Wang J, Wang Y, Ren Y. A case-control study on balance function of attention deficit hyperactivity disorder (ADHD) children. Beijing Da Xue Xue Bao. 2003;35:280–3. [PubMed] [Google Scholar]
- 25.Lopez C, Blanke O, Mast FW. The human vestibular cortex revealed by coordinate-based activation likelihood estimation meta-analysis. Neuroscience. 2012;212:159–79. doi: 10.1016/j.neuroscience.2012.03.028. [DOI] [PubMed] [Google Scholar]
- 26.Ferrè ER, Bottini G, Haggard P. Vestibular modulation of somatosensory perception. Eur J Neurosci. 2011;34:1337–44. doi: 10.1111/j.1460-9568.2011.07859.x. [DOI] [PubMed] [Google Scholar]
- 27.Ferrè ER, Sedda A, Gandola M, Bottini G. How the vestibular system modulates tactile perception in normal subjects: A behavioural and physiological study. Exp Brain Res. 2011;208:29–38. doi: 10.1007/s00221-010-2450-9. [DOI] [PubMed] [Google Scholar]
- 28.Ferrè ER, Bottini G, Haggard P. Vestibular inputs modulate somatosensory cortical processing. Brain Struct Funct. 2012;217:859–64. doi: 10.1007/s00429-012-0404-7. [DOI] [PubMed] [Google Scholar]
- 29.Ferrè ER, Day BL, Bottini G, Haggard P. How the vestibular system interacts with somatosensory perception: A sham-controlled study with galvanic vestibular stimulation. Neurosci Lett. 2013;550:35–40. doi: 10.1016/j.neulet.2013.06.046. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 30.Preuss N, Mast FW, Hasler G. Purchase decision-making is modulated by vestibular stimulation. Front Behav Neurosci. 2014;8:51. doi: 10.3389/fnbeh.2014.00051. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 31.Allum JH, Pfaltz CR. Visual and vestibular contributions to pitch sway stabilization in the ankle muscles of normals and patients with bilateral peripheral vestibular deficits. Exp Brain Res. 1985;58:82–94. doi: 10.1007/BF00238956. [DOI] [PubMed] [Google Scholar]
- 32.Haghshenas S, Hosseini MS, Aminjan AS. A possible correlation between vestibular stimulation and auditory comprehension in children with attention-deficit/hyperactivity disorder. Psychol Neurosci. 2014;7:159–62. [Google Scholar]
- 33.Wiszomirska I, Kaczmarczyk K, Blazkiewicz M, Wit A. The impact of a vestibular-stimulating exercise regime on postural stability in people with visual impairment. Biomed Res Int. 2015;2015:136969. doi: 10.1155/2015/136969. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 34.Badke MB, Miedaner JA, Shea TA, Grove CR, Pyle GM. Effects of vestibular and balance rehabilitation on sensory organization and dizziness handicap. Ann Otol Rhinol Laryngol. 2005;114(1 Pt 1):48–54. doi: 10.1177/000348940511400109. [DOI] [PubMed] [Google Scholar]
- 35.Badke MB, Shea TA, Miedaner JA, Grove CR. Outcomes after rehabilitation for adults with balance dysfunction. Arch Phys Med Rehabil. 2004;85:227–33. doi: 10.1016/j.apmr.2003.06.006. [DOI] [PubMed] [Google Scholar]
- 36.Wrisley DM, Stephens MJ, Mosley S, Wojnowski A, Duffy J, Burkard R. Learning effects of repetitive administrations of the sensory organization test in healthy young adults. Arch Phys Med Rehabil. 2007;88:1049–54. doi: 10.1016/j.apmr.2007.05.003. [DOI] [PubMed] [Google Scholar]
- 37.Dilda V, MacDougall HG, Curthoys IS, Moore ST. Effects of galvanic vestibular stimulation on cognitive function. Exp Brain Res. 2012;216:275–85. doi: 10.1007/s00221-011-2929-z. [DOI] [PubMed] [Google Scholar]