Galvanic vestibular stimulation improves arm position sense in spatial neglect: a sham-stimulation-controlled study

Area of Science:

• Neuroscience
• Rehabilitation Medicine
• Clinical Neurology

Background:

• Arm position sense (APS) deficits are common and disabling in stroke survivors with hemiparesis, particularly those with spatial neglect.
• Contralesional APS is significantly impaired in patients experiencing spatial neglect.
• Currently, no effective treatments exist for disturbed APS following stroke.

Purpose of the Study:

• To evaluate the immediate and short-term aftereffects of subsensory bipolar galvanic vestibular stimulation (GVS) on APS.
• To compare the effects of GVS on APS in stroke patients with and without spatial neglect, as well as in healthy controls.

Main Methods:

• A novel optoelectronic device precisely measured horizontal APS in both arms.
• Participants included 10 healthy controls, 15 stroke patients without neglect, and 7 stroke patients with left-sided hemiparesis and spatial neglect.
• APS was assessed under four conditions: baseline, left-cathodal/right-anodal GVS, right-cathodal/left-anodal GVS, and sham GVS, examining both immediate and 20-minute aftereffects.

Main Results:

• Stroke patients with neglect demonstrated significantly impaired contralateral APS compared to those without neglect and healthy controls.
• Left-cathodal/right-anodal GVS led to significant improvement in left APS, reaching normal ranges 20 minutes post-stimulation.
• GVS did not affect APS in patients without neglect, but right-cathodal/left-anodal GVS impaired APS in healthy participants.

Conclusions:

• Galvanic vestibular stimulation (GVS) offers a promising therapeutic approach for improving impaired arm position sense in patients with spatial neglect.
• Further research into multisession GVS is warranted to explore its potential for inducing lasting therapeutic benefits.