Effect of Transcranial Direct Current Stimulation on Postural Stability and Lower Extremity Strength in Hemiplegic Stroke Patients

Abstract

ObjectiveTo evaluate the effect of anodal transcranial direct current stimulation (tDCS) over the lesioned leg motor cortex, which can enhance the strength and coordination of the contralateral lower extremity and furthermore, enhance the postural stability of the hemiplegic subject.MethodsAnodal or sham stimulation on the lesioned cortex of a lower extremity was delivered to 11 ambulatory hemiplegic patients. The stimulation intensity was 2 mA. All subjects took part in two 10-minute tDCS sessions consisting of anodal stimulation and sham stimulation. The interval period between real and sham stimulation was 48 hours. The order was counter-balanced among the subjects. Before and after each stimulation session, static postural stability was evaluated with eyes opened and closed. Also, the isometric strength of the hemiplegic side of the treated knee was measured before and after each stimulation session. Repeated measure ANOVA was used to determine the statistical significance of improvements in postural stability and strength.ResultsThere was significant improvement for overall stability index with eyes opened and closed after anodal tDCS (p<0.05). Isometric strength of the lesioned quadriceps tended to increase after anodal tDCS (p<0.05). Postural stability and quadriceps strength were not changed after sham stimulation.ConclusionAnodal tDCS has potential value in hemiplegic stroke patients to improve balance and strengthen the affected lower extremity.

Transcranial Direct Current Stimulation of the Leg Motor Cortex Enhances Coordinated Motor Output During Walking With a Large Inter-Individual Variability

“…Previous studies showed that tDCS over the leg motor cortex can influence force generation and control in single leg joints in healthy subjects [7] as well as chronic stroke survivors [11][12][13]. At least for healthy subjects, our results extend these findings as we demonstrated (despite the large variability) that tDCS can result in an increased force production during the push off phase of walking, such that the propulsive impulse increases.…”

“…[11] to 20% [12]. Hence, our results indicate that the effects found in single leg joints do not necessarily transfer to whole body ambulation.…”

“…To improve the lower limb coordination of stroke patients, some studies have assessed the effects of anodal tDCS over the lesioned hemisphere on the force production and motor control in a single leg joint. Anodal stimulation resulted in an increased paretic knee extensor force generation [11,12] and improved learning of a motor skill task with the paretic ankle [13]. Recently, a study showed that effects of tDCS in the lower extremities are not solely at the single joint level, but could also improve the performance on a functional task.…”

Enhancement of Cortical Excitability and Lower Limb Motor Function in Patients With Stroke by Transcranial Direct Current Stimulation

“…They found that anodal tDCS stimulation positively influences voluntary control in the paretic ankle. In 2013, Sohn et al [14] reported that applying anodal tDCS (one 10-min session at 2 mA) to the affected lower limb primary motor cortex in 11 stroke patients enhanced the isometric strength of the affected quadriceps and postural stability. In 2014, Tahtis et al [15] assessed the effect of bicephalic tDCS (one 15-min session at 2 mA) on gait performance in 14 patients during the subacute stage of stroke (2e8 weeks after onset).…”

Noninvasive Neuromodulation in Poststroke Gait Disorders

“…122,123 Moreover, the effect of tDCS on fine motor control of the paretic foot has been evaluated by applying anodal or sham tDCS in random order over the lower limb M1 of the lesioned or nonlesioned hemisphere. In each session, tDCS was associated with a motor task that consisted of tracking a sinusoidal waveform for 15 minutes using dorsiflexion-plantar flexion movements of their paretic ankle.…”