Sinusoidal Transcranial Direct Current Versus Galvanic Vestibular Stimulation for Treatment of Lateropulsion Poststroke

Objective: To compare the effects of Transcranial Direct Current Stimulation (tDCS) versus Galvanic Vestibular Stimulation (GVS) on Lateropulsion following stroke. Methods: Patients with Stroke and Burke Lateropulsion Scale (BLS) scores greater than or equal to 2 gave informed consent to receive sinusoidal 1 Hz DC (0-2 mA) anodal stimulation over the affected parietal cortex versus similar GVS with ipsilesional mastoidal anode. Seated haptic center of pressure (COP-X) was measured using an AMTI analog-to-digital forceplate. An inclinometer (Biopac ) measured lateral thoracic tilt. COP-X Power Spectra were analyzed over 3 frequency intervals: 0-.3 Hz, .3-1 Hz, and 1-3 Hz. Results: Six males/4 females age 66 +/- 9.5 standard deviation with admission BLS scores of 5.4 +/- 3.7 within 8.6 +/- 8.1 days poststroke were enrolled. COP-X medial-lateral speed increased for both the tDCS and the GVS protocols compared to sham condition. Fourier Analysis of COP-X velocity for 0-.3 Hz responses showed a significant increase for tDCS stimulation. The 0.3-1 Hz responses for the tDCS condition were decreased from baseline. Lateral thoracic tilt showed significant improvement for tDCS compared to Sham stimulation at 10 minutes and for GVS versus Sham at 15 minutes. Discussion: Anodal tDCS over the ipsilesional PIVC increases low frequency postural responses usually attributed to visual control with down regulation of median frequency vestibular responses, biasing postural control toward more dependence on visual as opposed to vestibular control. Conclusions: 2 mA sinusoidal 1 Hz anodal tDCS over the ipsi-lesional PIVC or similar ipsi-lesional anodal GVS improve Lateropulsion following stroke.