Effects of repetitive galvanic vestibular stimulation on spatial neglect and verticality perception—a randomised sham-controlled trial

Abstract

Recent evidence shows that bipolar galvanic vestibular stimulation (GVS) with the cathode on the left (CL) or right (CR) mastoid ameliorates spatial neglect, extinction and verticality perception transiently and partly permanently. However, no randomised controlled trial evaluated the long-term effects of repetitive GVS in comparison to sham-GVS on exploration and verticality perception. To compare the effects of CL-GVS, CR-GVS and Sham-GVS on spatial exploration and verticality perception in right-hemispheric stroke patients with left neglect we conducted a randomised controlled trial with minimisation. Twenty-four patients completed 10-12 training sessions on a daily basis, 5 days/week. The CL-and CR-GVS group received 20 min of stimulation at 1.5 mA, the Sham-GVS group only 30 s of CL-GVS. Simultaneously, all patients performed a standard therapy of smooth pursuit eye movement training (SPT) followed by visual scanning training (VST). Outcome measures (Neglect test, visuo-tactile search task, subjective visual and tactile vertical) were assessed before and immediately after the intervention and at 2- and 4-week follow-ups. Our results show that neither our standard therapy nor the combination of standard therapy and GVS improved neglect symptoms significantly. The reasons for our non-significant results are discussed.

<p>Unilateral Spatial Neglect After Stroke: Current Insights</p>

“…136 While previous studies showed vestibular stimulation effects on egocentric spatial neglect symptoms, authors interestingly reported that L-GVS significantly improved egocentric neglect (assessed by line bisection and text copying task) whereas R-GVS results in amelioration of allocentric neglect (evaluated by figure copying and digit cancellation tasks). However, two recent RCTstudies, using repeated sessions of stimulations (10-12 sessions) 137 did not observe any post-treatment effects by GVS on neglect symptomatology. 137,138 Future studies are necessary to better understand the specific influence of GVS on disorders of spatial awareness and its potential in neglect rehabilitation.…”

“…However, two recent RCTstudies, using repeated sessions of stimulations (10-12 sessions) 137 did not observe any post-treatment effects by GVS on neglect symptomatology. 137,138 Future studies are necessary to better understand the specific influence of GVS on disorders of spatial awareness and its potential in neglect rehabilitation. As shown in Table 3, only 3 out of 9 studies were classified as class I investigations.…”

Adaptive Cueing Treatment of Neglect in Stroke Patients Leads to Improvements in Activities of Daily Living: A Randomized Controlled, Crossover Trial

“…Similar results were found in a study combining tDCS and an optokinetic drift task, which mainly improved egocentric symptoms in left-sided neglect patients. 11 No effect was found in Volkening et al, 37 investigating only bipolar galvanic vestibular stimulation and in combination with a visual search training conducted over 2 weeks. In the present study, we combined endogenous and exogenous cues, adapted to neglect severity.…”

Unilateral Spatial Neglect Recovery Poststroke

“…Only one study found no effect of time or intervention on USN in subacute right hemisphere stroke. 59 In this study, participants received active or sham galvanic vestibular stimulation during smooth pursuit eye movement training and visual scanning training for 10 to 12 sessions. Another study investigating continuous theta burst stimulation (cTBS; 8 cTBS and 16 cTBS dosages) versus sham demonstrated promising but weak evidence for active stimulation effectiveness in participants with USN in subacute right hemisphere stroke.…”