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Objectives Intention tremor becomes evident only when patients intend to move their body and is characterized by dysmetria. We have developed an on-demand control system that triggers the switching on/off of deep brain stimulation (DBS) instantly for the control of intention tremor. Material and Methods We used surface electrodes for the recording of electromyographic (EMG) activity, and the power of EMG activity was analyzed instantly employing the fast Fourier transform. The on-demand control system switched on DBS when only the power of tremor frequency exceeded the on-trigger threshold, and the system switched off DBS when the total power of EMG activity decreased below the off-trigger threshold. Results The on-demand control system triggered the switching on/off of DBS accurately, and controlled intention tremor completely. Our on-demand control system is small and portable, and suitable for clinical use. Conclusions The on-demand control system for DBS is useful for controlling intention tremor and may decrease the incidence of tolerance to DBS and may be a powerful tool for various applications of neuromodulation therapy.

Objective High-intensity and high-frequency repetitive transcranial magnetic stimulation (rTMS) of the primary motor cortex was carried out in poststroke patients with increased spasticity, and the changes in F-wave parameters in comparison with M-wave parameters induced by rTMS were examined. Methods Ten-hertz rTMS pulses were delivered to the primary motor cortex of the lesion side at 110% intensity of the resting motor threshold, and F-waves were obtained from the first dorsal interosseous muscle. F-waves were recorded before (pre-stim) and immediately after the end of rTMS (post-stim) in poststroke patients. Results F-wave persistence and F/M Amp.Ratio increased significantly in patients with lesions in upper motor tract as compared with healthy subjects (Wilcoxon rank sum test, p = 0.00023 and p = 0.0073, respectively). After the rTMS application, both F-wave persistence and F/M Amp.Ratio decreased significantly (paired t-test, p = 0.0095 and p = 0.037, respectively). However, the F-wave amplitude did not show a statistically significant variance in poststroke patients. Conclusions High-frequency suprathreshold rTMS may suppress the F-waves by enhancing the inhibitory effect on spinal excitability through the corticospinal tract, and F-wave persistence and F/M Amp.Ratio can be used to determine the effect of rTMS on patients with increased spasticity.

Introduction. Chronic thalamic stimulation has been confirmed as an effective treatment for tremor. The optimal target has been commonly accepted to be situated within the ventral thalamus, but a standard trajectory of the deep brain stimulation (DBS) electrode has not yet been established. Materials and Methods. A 53-year-old man with an 11-year history of essential tremor was treated by DBS of the thalamus. In this patient, we had a chance to compare the effects of different trajectory angles of the DBS electrode on tremor. Results. Intraoperative stimulation with the DBS electrode temporarily inserted at a high angle to the horizontal plane of the anterior commissure-posterior commissure (AC-PC) line to cover only the nucleus ventralis intermedius (Vim) was not effective. In contrast, stimulation with the DBS electrode permanently implanted at a low angle, covering a wide area extending from the nucleus ventralis oralis (Vo) to the Vim, reduced the tremor. Conclusion. We report on the case of a patient who showed different effects on tremor depending on the trajectory angle of the DBS electrode to the AC-PC line. The insertion trajectory of the DBS electrode may be an important factor for the treatment of tremor.

Spinal cord stimulation (SCS) is used to treat for several types of intractable pain syndromes, but it is not commonly used for treating post-stroke pain. Therefore, in this study, we analyzed the effects of SCS in patients with post-stroke pain. Neurological imaging and pharmacological analysis using thiopental, ketamine and morphine tests were conducted for 30 patients with post-stroke pain. For all patients, percutaneous electrodes were inserted under local anesthesia, and trial stimulation was performed for 5–7 days. If the patient experienced pain relief during the trial stimulation, a pulse generator was implanted. Of the 30 patients, 26 (87%) experienced satisfactory pain relief and underwent implantation. Ten patients received dual-octad lead SCS. The stimulation induced adequate paresthesia in all 10 patients. Nine (90%) of the 10 patients experienced satisfactory pain relief and opted for pulse generator implantation in order to proceed with the treatment. Upper cervical SCS was performed for patients with pain in not only the upper and lower extremities but also the face. Upper cervical SCS provided good paresthesia coverage and was effective for such patients. We think that patients with post-stroke pain may respond favorably to dual-octad lead SCS, and advancements in devices for SCS would further improve treatment outcomes for such patients.