ABSTRACT
PURPOSE: To assess the effects of atDCS on motor performance in patients with multiple sclerosis (MS). Previously, anodal transcranial direct current stimulation (atDCS) has been shown to improve motor performance in healthy subjects and neurodegenerative populations. However, the effect of atDCS on motor performance is not examined in MS. METHODS: In the current study, a sham controlled double-blind crossover design was used to evaluate the effect of 20 minutes of 1 mA atDCS or sham tDCS (stDCS) on a unimanual motor sequence-training task, consisting of sequential finger presses on a computer keyboard with the most impaired hand. Patients received stimulation (atDCS or stDCS) during motor training. tDCS was applied over the primary motor cortex contralateral to the most impaired hand. Motor performance was assessed immediately before, during and 30 minutes after stimulation. RESULTS: Although we need to be careful with the interpretation of the data due to lack of power, our results showed no significant effect of atDCS on motor performance. CONCLUSIONS: Our findings indicate that atDCS-supported motor training was not able to improve motor performance more than sham-supported motor training. Possibly, the effects of atDCS are mediated by specific MS-related characteristics. Furthermore, increasing atDCS intensity and offering multiple stimulation sessions might be necessary to optimize motor performance resulting from atDCS-supported motor training.
Subject(s)
Electric Stimulation Therapy , Motor Cortex/physiopathology , Motor Skills/physiology , Multiple Sclerosis/therapy , Adult , Aged , Cross-Over Studies , Double-Blind Method , Evoked Potentials, Motor/physiology , Female , Humans , Male , Middle Aged , Motor Cortex/physiology , Neuropsychological Tests , Treatment OutcomeABSTRACT
The application of anodal transcranial direct current stimulation (atDCS) to the human brain has been shown to elicit corticospinal (CS) excitability changes. This study evaluated the effect of a single session of atDCS on CS excitability in patients with multiple sclerosis (MS). atDCS and sham tDCS (stDCS) were applied to the primary motor cortex (M1) contralateral to the more severely impaired hand for 20min in a double-blinded crossover design. Changes in CS excitability were assessed using transcranial magnetic stimulation (TMS). The area under the recruitment curves increased significantly after application of atDCS (+56.58%, p=0.023) but not after stDCS. A sigmoidal curve-analysis revealed a higher plateau of the curve after atDCS (+22.2%, p<0.001). Our results showed that atDCS over M1 has the ability to increase CS output and projection strength in MS-patients, suggesting that atDCS can be considered during neural rehabilitation to facilitate motor recovery in MS.
Subject(s)
Brain/physiopathology , Electric Stimulation Therapy , Multiple Sclerosis/therapy , Spinal Cord/physiopathology , Adult , Aged , Cross-Over Studies , Double-Blind Method , Electrodes , Female , Humans , Male , Middle Aged , Multiple Sclerosis/physiopathologyABSTRACT
Although tDCS has been shown to improve motor learning, previous studies reported rather small effects. Since physiological effects of tDCS depend on intensity, the present study evaluated this parameter in order to enhance the effect of tDCS on skill acquisition. The effect of different stimulation intensities of anodal tDCS (atDCS) was investigated in a double blind, sham controlled crossover design. In each condition, thirteen healthy subjects were instructed to perform a unimanual motor (sequence) learning task. Our results showed (1) a significant increase in the slope of the learning curve and (2) a significant improvement in motor performance at retention for 1.5 mA atDCS as compared to sham tDCS. No significant differences were reported between 1 mA atDCS and sham tDCS; and between 1.5 mA atDCS and 1 mA atDCS.
