No additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability: a randomised controlled trial

Objectives This study explored whether adding transcranial direct current stimulation (tDCS) to balance exercises enhances preparatory brain activity and clinical outcomes in individuals with chronic ankle instability.Methods 30 participants were randomised into two groups: balance exercises with re...

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Main Authors: Zivar Beyraghi, Roya Khanmohammadi
Format: Article
Language:English
Published: BMJ Publishing Group 2025-04-01
Series:BMJ Open Sport & Exercise Medicine
Online Access:https://bmjopensem.bmj.com/content/11/2/e002401.full
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author Zivar Beyraghi
Roya Khanmohammadi
author_facet Zivar Beyraghi
Roya Khanmohammadi
author_sort Zivar Beyraghi
collection DOAJ
description Objectives This study explored whether adding transcranial direct current stimulation (tDCS) to balance exercises enhances preparatory brain activity and clinical outcomes in individuals with chronic ankle instability.Methods 30 participants were randomised into two groups: balance exercises with real tDCS and balance exercises with sham tDCS. Neurophysiological measures, including late contingent negative variation (CNV) amplitude, peak amplitude and peak time, served as primary outcomes, while biomechanical (anticipatory postural adjustment duration) and clinical (dynamic balance and perceived ankle instability) outcomes were secondary. Both groups completed 12 sessions, each lasting 60 min.Results The results revealed no significant group-by-time interaction for late CNV amplitude, CNV peak amplitude, perceived ankle instability scores or dynamic balance, indicating no added benefit of real tDCS over sham. However, both groups demonstrated significant post-treatment improvements in late CNV amplitude (C3, Cz, C4: p≤0.017, η2=0.177–0.276) and CNV peak amplitude at the C3 electrode (p=0.026, η2=0.158), reflecting enhanced preparatory brain activity. Similarly, dynamic balance improved significantly in the anterior, posterior-medial and posterior-lateral directions (p≤0.010, η2=0.204–0.350) and perceived ankle instability scores increased notably, indicating reduced instability (p<0.001, η2=0.391), regardless of the tDCS condition. Furthermore, significant correlations (r=0.381–0.553) were observed between treatment-induced changes in neurophysiological variables and biomechanical and clinical outcomes.Conclusions Although tDCS did not show a distinct advantage, the improvements in neurophysiological and clinical outcomes suggest that balance exercises effectively target central mechanisms. Additionally, relationships were found between enhancements in neurophysiological outcomes and other measures, emphasising the pivotal role of central mechanisms in driving these positive effects.Trial registration number IRCT20210604051488N1.
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spelling doaj-art-4e06a77e12ba4c838b504f9263358ca32025-08-20T02:16:28ZengBMJ Publishing GroupBMJ Open Sport & Exercise Medicine2055-76472025-04-0111210.1136/bmjsem-2024-002401No additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability: a randomised controlled trialZivar Beyraghi0Roya Khanmohammadi1Physical Therapy Department, Tehran University of Medical Sciences, Tehran, Iran (the Islamic Republic of)Physical Therapy Department, Tehran University of Medical Sciences, Tehran, Iran (the Islamic Republic of)Objectives This study explored whether adding transcranial direct current stimulation (tDCS) to balance exercises enhances preparatory brain activity and clinical outcomes in individuals with chronic ankle instability.Methods 30 participants were randomised into two groups: balance exercises with real tDCS and balance exercises with sham tDCS. Neurophysiological measures, including late contingent negative variation (CNV) amplitude, peak amplitude and peak time, served as primary outcomes, while biomechanical (anticipatory postural adjustment duration) and clinical (dynamic balance and perceived ankle instability) outcomes were secondary. Both groups completed 12 sessions, each lasting 60 min.Results The results revealed no significant group-by-time interaction for late CNV amplitude, CNV peak amplitude, perceived ankle instability scores or dynamic balance, indicating no added benefit of real tDCS over sham. However, both groups demonstrated significant post-treatment improvements in late CNV amplitude (C3, Cz, C4: p≤0.017, η2=0.177–0.276) and CNV peak amplitude at the C3 electrode (p=0.026, η2=0.158), reflecting enhanced preparatory brain activity. Similarly, dynamic balance improved significantly in the anterior, posterior-medial and posterior-lateral directions (p≤0.010, η2=0.204–0.350) and perceived ankle instability scores increased notably, indicating reduced instability (p<0.001, η2=0.391), regardless of the tDCS condition. Furthermore, significant correlations (r=0.381–0.553) were observed between treatment-induced changes in neurophysiological variables and biomechanical and clinical outcomes.Conclusions Although tDCS did not show a distinct advantage, the improvements in neurophysiological and clinical outcomes suggest that balance exercises effectively target central mechanisms. Additionally, relationships were found between enhancements in neurophysiological outcomes and other measures, emphasising the pivotal role of central mechanisms in driving these positive effects.Trial registration number IRCT20210604051488N1.https://bmjopensem.bmj.com/content/11/2/e002401.full
spellingShingle Zivar Beyraghi
Roya Khanmohammadi
No additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability: a randomised controlled trial
BMJ Open Sport & Exercise Medicine
title No additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability: a randomised controlled trial
title_full No additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability: a randomised controlled trial
title_fullStr No additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability: a randomised controlled trial
title_full_unstemmed No additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability: a randomised controlled trial
title_short No additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability: a randomised controlled trial
title_sort no additive effect of transcranial direct current stimulation on balance exercises for brain activity and clinical outcomes in patients with chronic ankle instability a randomised controlled trial
url https://bmjopensem.bmj.com/content/11/2/e002401.full
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