INTRODUCTION: Non-invasive electrical stimulation of the human cortex by means of transcranial direct current stimulation (tDCS) has been involved in a number of important discoveries in the field of human cortical function and has become a well-established method for enhancing brain function in healthy human participants. Recently, transcranial alternating current stimulation (tACS) has been introduced to directly modulate human cortical excitability. Transcranial pulsed current stimulation (tPCS) is another variant of non- invasive electrical stimulation which could be used as a novel technique to enhance corticomotor excitability. No direct electrophysiological evidence of tPCS has been reported. AIM: to compare the effects of tPCS with conventional tDCS on the enhancement of corticomotor excitability in healthy individuals. METHODS: Eight right handed healthy volunteers were tested in two separate sessions at least 48 hours apart. Corticomotor excitability of the dominant primary motor cortex of the resting right extensor carpi radialis muscle (ECR) was assessed before, immediately, 10, 20 and 30 minutes after application of tDCS or tPCS. In the tDCS session the current was applied for 10 minutes at 1mA current intensity. In tPCS, the pulse duration and inter-pulse interval were set at 500 ms and 50 ms respectively. The current intensity was set at 1.7 mA and the overall length of tPCS application was 5 minutes. The total charges for both applications were kept constant in all experiments. The outcome measure in this study was the amplitude of motor evoked potentials (MEPs) elicited by a single-pulse TMS (Magstim Company Limited, UK). Peak-to-peak amplitude of 15 MEPs were averaged and used for data analysis. All therapeutic and assessment procedures were approved by Monash Ethics Committee. RESULTS: A three-way ANOVA (SPSS 19) indicates that corticomotor excitability increases significantly following a-tDCS and tPCS application and this increase remains higher than baseline values during all post intervention assessments (p<0.05). This test also reveals that the percentages of change is larger in tPCS compared to tDCS (p<0.05). Only 30% of the subjects experienced very mild itching and burning sensations during the tPCS or tDCS applications. During application of tPCS, 70% of the volunteers experienced phosphene. CONCLUSION: Both tDCS and tPCS induce corticomotor excitability and this excitability remains higher than the baseline value at least 30 minutes after the intervention. Compared to tDCS, tPCS induces larger corticomotor excitability of ECR muscles in healthy individuals. More research should be done to explore optimal parameters for this novel therapeutic technique.
|Number of pages||1|
|Publication status||Published - 19 Jul 2012|
|Event||Congress of the International Society of Electrophysiology and Kinesiology 2012 - Queensland University of Technology, Brisbane, Australia|
Duration: 19 Jul 2012 → 21 Jul 2012
Conference number: XIXth
|Conference||Congress of the International Society of Electrophysiology and Kinesiology 2012|
|Period||19/07/12 → 21/07/12|