Peter K.W. Lee

LoNG-TERM EFFECTS oF rTMS oN MoToR RECoVERY IN PATIENTS AFTER SuBACuTE STRoKE

OBJECTIVE Repetitive transcranial magnetic stimulation (rTMS) has been recognized as a promising intervention for treatment of stroke patients. However, most previous reports have described the short-term effects of rTMS on motor performance. We conducted a sham-controlled trial to evaluate long-term effects of high-frequency rTMS on motor recovery in subacute stroke patients. METHODS Twenty-eight patients were randomly divided into two groups, and received either real or control rTMS. Both treatments were accompanied by motor practice. A daily dose of 1000 pulses of subthreshold 10 Hz rTMS was applied over the primary motor cortex of the affected hemisphere for 10 days within one month after onset of stroke. Motor function was assessed before and after treatment, and 3 months after the stroke. RESULTS Motor function improved in both groups after treatment; however, patients who received real rTMS experienced additional improvement in motor function of the affected upper limb. Over 3 months after the stroke, the time and type of intervention for the Motoricity Index of the affected upper extremity showed significant interaction. CONCLUSION Positive long-term effects on motor recovery could be achieved after 10 daily sessions of high-frequency rTMS in conjunction with motor practice during the sub-acute period of stroke.

Facilitative effect of high frequency subthreshold repetitive transcranial magnetic stimulation on complex sequential motor learning in humans

We investigated the effect of repetitive transcranial magnetic stimulation (rTMS) applied to the motor cortex, on the motor learning of sequential finger movements. Fifteen healthy subjects were trained to perform seven sequential finger movements of the left hand. Ten Hertz or sham rTMS with a resting motor threshold of 80% was applied to each subject during the task period. Stimulation with 10Hz rTMS produced a better learning performance in terms of target score and execution time than sham stimulation. We conclude that high-frequency rTMS may modulate the excitability of the motor cortex and facilitate the sequential motor learning process in normal subjects. These findings may provide a basis for the development of therapeutic applications of rTMS in patients with impaired motor skill.

Effect of muscle activity and botulinum toxin dilution volume on muscle paralysis

The purpose of this study was to evaluate the effects of botulinum toxin A (BTX-A, Botox) dilution volume and post-injection exercise with electrical stimulation on muscle paralysis. We injected 10 units of BTX-A diluted with 0.1 ml (B1, n=8) or 0.5 ml (B5, n=8) normal saline into both gastrocnemius muscles of 16 New Zealand white rabbits; two controls received no BTX-A. After BTX-A injection, all rabbits received calf muscle stretching exercise and electrical stimulation for 2 hours on the left leg. The compound muscle action potential (CMAP) decrease was most pronounced at 1 week and progressive recovery was observed (i.e. recovery from paralysis, increase of CMAP). There was a significant decrease of CMAP amplitudes in the B5 group compared with the B1 group at week 1 and week 4 (p<0.001). Left limbs with stretching exercise and electrical stimulation showed lower CMAP amplitudes compared with control right limbs of all rabbits. To maximize the muscle paralysis effect of BTX-A, increasing dilution volume and performing post-injection stretching exercise with electrical stimulation may be a promising strategy for increasing the beneficial effect of BTX-A treatment. Future studies are needed to investigate the clinical application of this finding.The purpose of this study was to evaluate the effects of botulinum toxin A (BTX‐A, Botox) dilution volume and post‐injection exercise with electrical stimulation on muscle paralysis. We injected 10 units of BTX‐A diluted with 0.1 ml (B1, n=8) or 0.5 ml (B5, n=8) normal saline into both gastrocnemius muscles of 16 New Zealand white rabbits; two controls received no BTX‐A. After BTX‐A injection, all rabbits received calf muscle stretching exercise and electrical stimulation for 2 hours on the left leg. The compound muscle action potential (CMAP) decrease was most pronounced at 1 week and progressive recovery was observed (i.e. recovery from paralysis, increase of CMAP). There was a significant decrease of CMAP amplitudes in the B5 group compared with the B1 group at week 1 and week 4 (p<0.001). Left limbs with stretching exercise and electrical stimulation showed lower CMAP amplitudes compared with control right limbs of all rabbits. To maximize the muscle paralysis effect of BTX‐A, increasing dilution volume and performing post‐injection stretching exercise with electrical stimulation may be a promising strategy for increasing the beneficial effect of BTX‐A treatment. Future studies are needed to investigate the clinical application of this finding.

Effects of hippotherapy on gait parameters in children with bilateral spastic cerebral palsy.

OBJECTIVES To evaluate the effects of hippotherapy on temporospatial parameters and pelvic and hip kinematics of gait in children with bilateral spastic cerebral palsy. DESIGN Nonrandomized prospective controlled trial. SETTING Outpatient therapy center. PARTICIPANTS Children (N=32) with bilateral spastic cerebral palsy, Gross Motor Function Classification System level 1 or 2. INTERVENTION Hippotherapy (30 min twice weekly for 8 consecutive weeks). MAIN OUTCOME MEASURES Temporospatial parameters and pelvic and hip kinematic parameters in 3-dimensional motion analysis, Gross Motor Function Measure (GMFM)-88, and score for dimensions D (standing) and E (walking, running, jumping) of the GMFM, GMFM-66, and Pediatric Balance Scale (PBS). RESULTS Hippotherapy significantly improved walking speed, stride length, and pelvic kinematics (average pelvic anterior tilt, pelvic anterior tilt at initial contact, pelvic anterior tilt at terminal stance). Scores for dimension E of the GMFM, GMFM-66 and PBS also increased. CONCLUSIONS Hippotherapy provided by licensed health professionals using the multidimensional movement of the horse may be used in conjunction with standard physical therapy for improvement of gait and balance in children with bilateral spastic cerebral palsy.

Facilitating visuospatial attention for the contralateral hemifield by repetitive TMS on the posterior parietal cortex

Previous studies have demonstrated that repetitive transcranial magnetic stimulation (rTMS) could modulate the visuospatial functions. In this study, we investigated the effect of off-line high frequency subthreshold rTMS, when applied over the right or left posterior parietal cortex (PPC), on the visuospatial attention of the bilateral hemispaces. The subjects underwent visuospatial tasks before and immediately after receiving 1000 pulses of 10 Hz rTMS for a period of 20 min, and their responses were recorded. Our results demonstrated that the high frequency rTMS applied over the PPC produced facilitative effects on the visuospatial attention to the contralateral hemispace. The inhibitory effect to the ipsilateral hemispace was noticeable only in the left PPC.

Neural correlates of donepezil-induced cognitive improvement in patients with right hemisphere stroke: A pilot study

Donepezil has been proven effective in the treatment of Alzheimers disease and vascular dementia. However, its effects on the cognitive neural network have not been fully investigated. The purpose of this study was to evaluate the effect of donepezil on reorganisation of the cognitive neural network in patients with post-stroke cognitive impairment using functional MRI (fMRI). Fourteen patients with stroke in the right hemisphere were enrolled. Participants were randomly assigned to the experimental or the control group. Donepezil (5 mg) or placebo was administered daily for four weeks. Cognitive function assessment was performed before and immediately after treatment, and repeated one month after cessation of treatment. fMRI was performed before and after treatment. Ten out of 14 patients (six in the experimental group, four in the control group) successfully completed all experimental processes. The experimental group showed significant improvements in the Mini-Mental Status Examination during the post-treatment evaluation and one-month follow-up compared to the pre-treatment evaluation (p < .05). No improvement was observed in the control group. In the experimental group fMRI showed increased activation in both prefrontal areas, both inferior frontal lobes, and in the left inferior parietal lobe. Increased recruitment of the parieto-frontal networks in the selected patients was considered to be a neural correlate of cognitive improvement induced by donepezil.