tDCS combined with optokinetic drift reduces egocentric neglect in severely impaired post-acute patients

Visuospatial neglect is a disabling syndrome resulting in impaired activities of daily living and in longer durations of inpatient rehabilitation. Effective interventions to remediate neglect are still needed. The combination of tDCS and an optokinetic task might qualify as a treatment method. A total of 32 post-acute patients with left (n = 20) or right-sided neglect were allotted to an intervention or a control group (both groups n = 16). The intervention group received eight sessions of 1.5-2.0 mA parietal transcranial direct current stimulation (tDCS) during the performance of an optokinetic task distributed over two weeks. Additionally they received standard therapy for five hours per day. The control group received only the standard therapy. Patients were examined twice before (with 3-4 days between examinations) and twice after treatment (5-6 days between examinations). Compared to the control group and controlling for spontaneous remission, the intervention group improved on spontaneous body orientation and the Clock Drawing Test. Intragroup comparisons showed broad improvements on egocentric but not on allocentric symptoms only for the intervention group. A short additional application of tDCS during an optokinetic task led to improvements of severe neglect compared to a standard neurological early rehabilitation treatment. Improvements seem to concern primarily egocentric rather than allocentric neglect.