Effect of vestibular stimulation on auditory and visual reaction time in relation to stress

A randomized controlled trial to evaluate the efficacy of electrical vestibular nerve stimulation (VeNS), compared to a sham control for the management of sleep in young adults

OBJECTIVES

Preliminary research suggests that electrical vestibular nerve stimulation (VeNS) may improve sleep outcomes by influencing the hypothalamus and brainstem nuclei involved in regulating the circadian rhythm and wakefulness. This randomised, sham-controlled trial aimed to assess the effectiveness of VeNS on insomnia in young adults.

METHODS

Eighty adults aged 18-24 years were randomly allocated to the intervention (n=40) and control groups (n=40). The intervention group was provided with 30 min per day of VeNS with five sessions weekly for four weeks, while the control group received sham stimulation for the same period. Baseline Insomnia Sleep Index (ISI) scores were recorded weekly. At baseline and at day 28, questionnaires to evaluate emotional states of depression, anxiety and stress, and quality of life (QoL) were completed. The primary outcome was change in ISI with comparison between baseline and day 28.

RESULTS

The VeNS group significantly reduced their mean ISI score after 7 days usage (p<0.001). At day 28 it was found that mean ISI scores had reduced from 19 to 11 in the VeNS group, and from 19 to 18 in the sham group, and the difference between the groups was significant (p<0.001). Moreover, application of VeNS appeared to significantly improve emotional state and QoL outcomes.

CONCLUSIONS

This trial demonstrates that regular VeNS usage over four weeks leads to a clinically meaningful decrease in ISI scores in young adults with insomnia. VeNS may have potential as a drug-free and non-invasive therapy to improve sleep outcomes by positively influencing the hypothalamic and brainstem nuclei.

Effectiveness of electrical vestibular nerve stimulation as adjunctive therapy to improve the cognitive functions in patients with Parkinson's disease

OBJECTIVES

The present study was undertaken to observe the effectiveness of electrical vestibular stimulation in improving cognitive functions in patients with Parkinson's disease.

METHODS

Randomized controlled trial (ClinicalTrials.gov Identifier: NCT04450550). 30 cases of PD, including both males and females were recruited in the study by convenient sampling after obtaining written informed consent. After recruiting, the participants were randomly assigned into two groups. The control group (n=15) received placebo stimulation whereas the intervention group (n=15) received electrical vestibular stimulation administered for 12 weeks. Auditory, visual reaction time and spatial and verbal memory were recorded before and after 6 weeks and after 12 weeks of intervention and compared.

RESULTS

There was a significant improvement in both auditory and visual reaction time of right and left-hand responses. Also, significant improvement was observed in both the spatial and verbal memory of the patients.

CONCLUSIONS

There was a significant improvement in the auditory and visual reaction time and spatial and verbal memory in the participants after the electrical vestibular nerve stimulation administration. No side effects were reported by the study participants and they have expressed willingness to continue the intervention after the study period also. The study recommends further detailed studies with a higher sample size to adopt electrical vestibular nerve stimulation as adjunctive therapy in the management of Parkinson's disease.

Caloric Vestibular Stimulation Induced Enhancement of Behavior and Neurotrophic Factors in Chronic Mild Stress Induced Rats

Background: Caloric Vestibular Stimulation (CVS) is a non-invasive technique for stimulating the vestibular system. The vestibular system maintains equilibrium and acts as a moderator of mood, emotional control, and stress levels. Stress is a disruption of psychological, behavioral, and physiological homeostasis that affects people of all ages in today's world. Thus, modest therapeutic procedures like vestibular stimulation can be practiced to effectively reduce stress. Hence, the purpose of the study was to determine the effect of vestibular stimulation on improving behavioral alterations and neurotrophic factors in rats exposed to Chronic Mild Stress (CMS). Methodology: The study employed 24 healthy male Sprague Dawley rats divided into four groups (n = 6). CMS was induced for 28 days with a variety of stimuli. Bilateral CVS with hot water (temperature ≈40°C) was started on Day 14 of CMS and continued for 15 days. On days 1, 15, and 28, locomotor activity (LA), wire grip strength (WGS), fall off time (FT), and immobilization time (IT) were measured, and the data were analyzed statistically. Additionally, neurotrophic factors such as Brain Derived Neurotrophic Factor (BDNF) and Glial cell line-Derived Neurotrophic Factor (GDNF) were observed in rats' hippocampus. Results: On days 15 and 28, the CMS-induced group showed a significant reduction in LA, WGS, FT and IT in comparison to the control group. On day 28, the CVS-induced group demonstrated a significant increase in WGS, FT and IT when compared to the CMS group. Immunohistochemical analysis revealed that animals subjected to CMS had decreased BDNF and GDNF expression compared to the control group, indicating neuronal dysfunction in the hippocampus in response to stress. However, therapy with CVS increased BDNF and GDNF expression, thereby regenerating damaged hippocampus nerve terminals. Conclusion: The findings of the current study revealed that CVS is a safe and simple neuroprotective treatment against stress and a promising non-invasive technique for overcoming the motor symptoms associated with it. The findings may pave the way for future research and therapeutic applications of CVS for stress management.

Electrical vestibular nerve stimulation (VeNS): a follow-up safety assessment of long-term usage

OBJECTIVES

This retrospective, open-label study was undertaken to assess the safety of repeated, long-term electrical vestibular nerve stimulation (VeNS). The primary outcome for this study was assessment of hearing function as reported by formal audiometry testing.

METHODS

Assessments were conducted on n=25 long-term users of daily 1.5 mA VeNS. Skin inspection of the mastoid area, otoscope examination of the inner ear, and formal audiometry testing was conducted on n=18 users. All participants completed a survey-based assessment to determine usage of the device, adverse events, and long-term outcomes.

RESULTS

Mean duration of use was 22 months, with approximately 80% of users reporting 1 h of daily, or 1 h of regular (2-3 times per week) VeNS usage. No adverse events were reported. There were no significant findings during examination of the mastoid areas, ear canal, or tympanic membranes. There were no significant findings reported from the formal audiogram assessments.

CONCLUSIONS

This appears to be the first study to provide formal assessment to show that repeated, long-term VeNS usage has not generated any significant side effects or adverse events. Results from this study further support previous literature that electrical vestibular stimulation is both safe and well-tolerated.