The Effect of High Frequency Repetitive Transcranial Magnetic Stimulation on the Motor Function in Post-Stroke Patients

OBJECTIVE: To evaluate the effects of high frequency repetitive transcranial magnetic stimulation (rTMS) of the affected hemisphere on the motor recovery and spasticity in chronic post-stroke hemiplegic patients. METHOD: Thirteen chronic stroke hemiplegic patients were randomized to receive real and sham rTMS. rTMS was carried out 10 times at a frequency of 10 Hz with 10 s stimulation followed by 50 s rest, totalling 1,000 stimulations to the affected primary motor cortex using an intensity of 100% of resting motor threshold of unaffected hemisphere. Median nerve H-reflex, modified Ashworth scale (MAS) at elbow and wrist, and manual function test (MFT) were measured at baseline and after 2 weeks of treatment. RESULTS: High frequency rTMS resulted in increased H-reflex latency and decreased H-reflex amplitude and H/M ratio. Also MAS decreased and MFT score increased after 2 weeks of treatment. CONCLUSION: High frequency rTMS in the affected motor cortex might facilitate motor recovery and reduce spasticity in chronic stroke patients.

Effects of Enriched Environment on Locomotion and Cognition in Neonatal Rats with Hypoxic-Ischemic Encephalopathy

OBJECTIVE: To investigate the effect of environmental enrichment on the cognitive and motor development in the experimental hypoxia-ischemic encephalopathy neonatal rat model. METHOD: Hypoxic-ischemic encephalopathy models were made in neonatal Sprague-Dawley rats at 3 days of age by ligating the unilateral carotid artery followed by inhalation of 8% oxygen and raised in the enriched environment (n=10), treadmill exercise (n=8) and non-stimulation (n=10) from the 3rd to 8th weeks of age. Neurobehavioral and histopathological changes were compared. RESULTS: The neurobehavioral tests of the rats with hypoxic-ischemic encephalopathy showed prolonged latencies of achievement for cliff avoidance and negative geotaxis (p<0.05). Persisting abnormality into adult life of limb placing improved in exercise and enriched environment groups and spatial learning and memory in a water maze recovered in the rats with enriched environment (p<0.05). The density of dendritic spine increased in the hippocampus with enriched environment (p<0.05). CONCLUSION: The present study supports the possibilities of the positive effects after the enriched environment in the developing brain with hypoxic injury.

Effects of 10 Hz Repetitive Transcranial Magnetic Stimulationin Acute Human Muscle Pain Model

OBJECTIVE: To investigate the analgesic effect of high frequency repetitive transcranial magnetic stimulation (rTMS) on the experimental human muscle pain and its underlying mechanism. METHOD: Twenty healthy Korean volunteers participated in this study. The acute muscle pain was induced by infusion of hypertonic saline (5%) into the left extensor carpi radialis longus (ECRL) muscle. During the hypertonic saline injection, 10 Hz rTMS were applied on the hot spot of left ECRL. The changes of visual analogue scale (VAS) of muscle pain and motor evoked potential (MEP) were measured from the start of saline injection to 70 minutes after the start of stimulation. At 90 minutes after the first stimulation, the subjects completed the Korean version of the McGill Pain Questionnaire (MPQ). The sham stimulation was applied with the same method as rTMS experiment. RESULTS: In rTMS, the VAS of muscle pain was significantly decreased from 2.5 minutes and continued until 3 minutes after the last rTMS. While the amplitude of MEP was significantly increased, the latency of MEP was significantly decreased after the start of rTMS and the effect on MEP continued until 5 minutes after the last rTMS. The quality of pain experiment by rTMS and sham stimulation showed no difference in MPQ. CONCLUSION: The present results suggested that 10 Hz rTMS over primary motor cortex decreased the perception of muscle pain and increased the excitability of corticospinal pathway.