This study aimed to investigate the change in the excitability of anterior horn cells of the spinal cord by evaluating the differences between the F waves using various observation targets for healthy subjects. The F wave was elicited from the right abductor digiti minimi (ADM). In the protocol, the F wave was first recorded at rest, and then recorded for one minute while the subject watched a video after a four-minute rest period. The video was showed three tasks of the right hand: a video showing movement of the little finger (task A); a video showing movements of little finger, ring finger, middle finger and index finger simultaneously (task B); and a video same as B but blurring the hand except the little finger (task C). The F/M amplitude ratio was investigated for the three tasks. As results the relative F/M amplitude ratio was significantly higher in tasks A and C than in task B. These results suggest that the excitability of the anterior horn cells innervating ADM was increased by visual attention directed to the movement of the little finger.

An 81-year-old man was referred to our psychiatry outpatient clinic for treatment of parasomnia. About 10 years previously, he had begun to experience visual hallucinations of small animals or persons during the night, and about 5 years later he had started to exhibit unusual nocturnal behavior such as speaking in a loud voice and falling out of bed. He had been treated by a physician at another clinic and prescribed medication including clonazepam, but this had not been effective for his parasomnia. Video polysomnography revealed severe obstructive sleep apnea syndrome (apnea hypopnea index 36.0/h) and REM sleep without atonia. A ¹²³I-ioflupane SPECT revealed reduced dopamine transporter uptake in the bilateral basal ganglia, and ¹²³I-MIBG scintigraphy demonstrated a reduced heart-to-mediastinum ratio, suggesting a probable diagnosis of dementia with Lewy bodies. We treated obstructive sleep apnea syndrome using continuous positive airway pressure therapy. In addition, we prescribed clonazepam for REM sleep behavior disorder and donepezil hydrochloride for the visual hallucinations due to dementia with Lewy bodies. This resulted in the disappearance of his nocturnal parasomnia symptoms. In this case, continuous positive airway pressure therapy may have improved the responsiveness of REM sleep behavior to clonazepam treatment. It is important to follow up this patient with careful monitoring in case of future cognitive decline.

Nerve conduction study (NCS) is a convincing tool for a diagnosis of neuromuscular diseases. NCS is routinely performed by a medical technologist based on a request by neurologists. Technologists have to understand the neurologists’ request, and, during the examinations, are required to interpretate the obtained data, and perform additional nerve conduction studies by their own judgement. This process is rather difficult for beginners, and we tried to make our original chart-type manual for the median nerve NCS for standardization of technique and flow of NCS among the technologists in our hospital. Carpal tunnel syndrome and Martin Gruber anastomosis are frequently encountered in a clinical setting, and the chart-type manual for median nerve was first aimed to make an appropriate diagnosis for those disorders. Particularly, the latency of the motor response and simultaneous recording from the abductor digiti minimi muscle was emphasized in the manual. Our manual was useful to establish the technique of NCS, reduce a psychological burden of the technologists, and shorten the examination time. Feedback of the results to neurologists and constant discussions with them were necessary for better revision of the manual and improvement of the examination skills.

EEG can detect brain dysfunction which is difficult to be detected by neuroimages and blood tests, therefore it is effective in diagnosing epilepsy, sleep medicine, and disturbance of consciousness. It is clinically significant that EEG makes it possible to investigate the relationship between symptoms and EEG by recording videos simultaneously. Long-term video EEG monitoring is useful to detect abnormalities that could not be extracted by short-time conventional EEG recording. Due to development of digital technologies and higher performance amplifiers, EEG became possible to record high-frequency and low-frequency EEG activities with a long-time scale, and several new knowledges have been obtained in the research fields. New research fields have been expanding; such as utilizing EEG as long-term biological signal sensor, introduction of machine learning for EEG data analysis, and trial use as a telemedicine and educational tool. The usefulness of EEG in the field of neurology and several examples of EEG/long-term video EEG monitoring as promising research tools will be introduced in this section.