Koji Aono

Premotor potential study in carpal tunnel syndrome

Introduction: Premotor potentials (PMPs) precede compound muscle action potentials evoked from the second lumbrical muscle after median nerve stimulation. Although PMP has been identified as a median sensory nerve action potential, few reports have documented the significance of PMP parameters for diagnosing carpal tunnel syndrome (CTS). Methods: We investigated the relationships between PMP parameters and results of 6 standard median nerve conduction studies in 74 CTS hands. Results: Significant correlations were noted in all comparisons. PMP conduction velocity was strongly correlated with the sensory conduction velocity between wrist and digit 2 (r2 = 0.91). Moreover, PMP parameters were significantly correlated with neurophysiological severity of CTS. Conclusion: Measuring PMP parameters with a second lumbrical–interosseous study may be useful for diagnosing CTS. Muscle Nerve, 2012

Effect of low-frequency repetitive transcranial magnetic stimulation combined with physical therapy on L-dopa-induced painful off-period dystonia in Parkinson's disease.

Previous research has shown that low-frequency repetitive transcranial magnetic stimulation over the primary motor area and supplementary motor area can reduce l-dopa-induced dyskinesias in Parkinsons disease; however, it involved only patients with peak-dose or diphasic dyskinesia. We report a case of a patient with severely painful off-period dystonia in the unilateral lower limb who underwent 0.9-Hz subthreshold repetitive transcranial magnetic stimulation over contralateral primary motor area and supplementary motor area. Repetitive transcranial magnetic stimulation over the primary motor area significantly reduced the painful dystonia and walking disturbances but repetitive transcranial magnetic stimulation over the supplementary motor area did not. The cortical silent period also prolonged after repetitive transcranial magnetic stimulation over the primary motor area. At 5 mos of approximately once a week repetitive transcranial magnetic stimulation over the primary motor area, the Unified Parkinsons Disease Rating Scale motor score also improved. This report shows that repetitive transcranial magnetic stimulation over the inhibitory primary motor area can be useful for rehabilitating patients with Parkinsons disease with off-period dystonia and suggests that this treatment should be further verified in such patients.

Feeling of Bodily Congruence to Visual Stimuli Improves Motor Imagery Based Brain-Computer Interface Control

Motor imagery based Brain-Computer Interface (BCI) utilizes an electrophysiological phenomenon of EEG power decrease in alpha frequency band, but its larger inter-subject variability limits the practical use. Here we tested three types of visual feedback objects in BCI from abstract to realistic scenarios during motor imagery to see its effect on self-induced changes of EEG power decrease. Double case study in hemiplegic stroke participants was also conducted to check its feasibility as neuro-facilitatory technique on the motor system. We found that a first person perspective of realistic visual feedback, which copies the participant’s mental image, assisted the user to perform motor imagery resulting in generation of large EEG power decrease. The same result was found also in hemiplegic stroke patients. This study has clear implications for both the mechanism of mental process of motor imagery and the influence of feedback type on BCI performance.

31. Modified second lumbrical-interossei method

This study was aimed to assess a correlation of event-related desynchronization (ERD) with primary motor cortex (M1) excitability during hand motor imagery. M1 excitability was tested by motor evoked potentials (MEPs), intracortical inhibition (ICI) and intracortical facilitation (ICF), using transcranial magnetic stimulation (TMS). Twenty healthy subjects were recruited in this study. Each subject performed 30 trials comprising 7 s of rest followed by 5 s of motor imagery of either right wrist flexion or extension. Subjects received real-time visual feedback of the ERD magnitude of electroencephalogram signals recorded over the hand area of the left M1. TMS was applied to the left M1 when ERD exceeded 5% or 15% thresholds during motor imagery. MEP size, ICI and ICF were recorded from the agonist muscle of the motor imagery. During hand motor imagery with ERD, MEP sizes increased and ICI reduced (p < 0.05), but there was no significant change in ICF. The changes of MEP-size and ICI were correlated with ERD magnitude. Our findings suggest that ERD magnitude may indicate changes of M1 excitability.

60. Changes in motor cortical excitability following electrical stimulation of the common peroneal nerve

acute sensory ataxia. The positive anti-Hu antibody suggested that he had anti-Hu-associated paraneoplastic subacute sensory neuropathy. The conventional nerve conduction studies and somatosensory evoked potentials revealed severe sensory neuropathy. For magnetic cerebellar stimulation, the test magnetic stimulus over the left primary motor cortex (M1) was preceded by the conditioning stimulus over the right cerebellum. Motor evoked potential was recorded from the right first dorsal interosseous muscle. The suppressive effect of magnetic cerebellar stimulation on the contralateral M1 was abnormally reduced. The results indicated that cerebellar efferent pathway or dentatothalamocortical pathway was involved in this patient, although cerebellar signs could not be evaluated due to severe sensory neuropathy. Magnetic cerebellar stimulation might be useful to reveal cerebellar dysfunction masked by coexisting sensory ataxia in patients with paraneoplastic sensory neuropathy.