Effects of anodal stimulation and motor practice on limb-kinetic apraxia in Parkinson's disease.

Limb-kinetic apraxia, the loss of the ability to make precise, independent but coordinated finger and hand movements affects quality of life in patients with Parkinson's disease. We aimed to examine the effects of anodal transcranial direct current stimulation of the left posterior parietal cortex and upper extremity motor practice on limb-kinetic apraxia in Parkinson's disease. This study was conducted in a randomized, double-blind, sham-controlled fashion. Patients confirmed to have Parkinson's disease were recruited. Twenty-eight participants completed the study and were randomized to two groups: anodal or sham stimulation. For participants assigned to active stimulation, anodal stimulation of the left posterior parietal cortex was performed using 2 mA current for 20 min. Patients received anodal or sham stimulation, followed by motor practice in both groups. The primary outcome measure was time-performing sequential buttoning and unbuttoning, and several secondary outcome measures were obtained. A statistically significant interaction between stimulation type and timepoint on time taken to perform buttoning and unbuttoning was found. Patients who received anodal stimulation were found to have a significant decrease in sequential buttoning and unbuttoning time immediately following stimulation and at 24 h in the medication-ON state, compared to the medication-OFF state (31% and 29% decrease, respectively). Anodal stimulation of the left posterior parietal cortex prior to motor practice appears to be effective for limb-kinetic apraxia in Parkinson's disease. Future long-term, multi-session studies looking at the long-term effects of anodal stimulation and motor practice on limb-kinetic apraxia in Parkinson's disease may be worthwhile.

Transcranial Direct Current Stimulation and Yoga for Functional Movement Disorders.

BACKGROUND: Functional movement disorder (FMD), a conversion disorder characterized by involuntary movements, is difficult to treat. METHODS: We aimed to assess the effects of anodal transcranial direct current stimulation (tDCS) and yoga in FMD patients (n=5). TDCS of the right temporoparietal junction, a brain region relevant in the sense of self-agency, was conducted. Subjects underwent both sham and anodal tDCS with a washout period of 3 weeks. Yoga was used as a mode of exercise, as well as in conjunction with stimulation to sustain potential changes in neural plasticity. RESULTS: A total of 5 subjects completed the study [mean age: 52 (SE: 4) y, disease duration: 5 (SE: 1.6) y], undergoing both sham and anodal tDCS. Anodal tDCS does not appear to be superior to sham tDCS in alleviating symptoms and disability, but combining tDCS and yoga appears to lead to mild improvement noted on clinical observation, based on the change in the efficacy index of Clinical Global Impression found in 4 subjects. CONCLUSION: Our study results suggest that anodal tDCS is not superior to sham tDCS in alleviating subjective symptoms and disability in FMD. However, interpretation of these results is limited due to the small number of stimulation sessions and number of subjects. Future studies using more frequent stimulation sessions are needed to further determine whether anodal tDCS may have a therapeutic effect in this patient group compared with sham tDCS.