[A biological rhythm in a patient with normal pressure hydrocephalus--comparative studies in pre- and postoperative patients by a polygraphy].

The authors had studies the correlation between the appearance of the pressure waves and the level of the sleep in pre- and postoperative patients with normal pressure hydrocephalus (NPH). The changes from preoperative findings to postoperative ones were discussed in detail with the relation of the pathophysiological state in these patients. Seventeen patients were evaluated for the suspected diagnosis of the disease of NPH. Thirteen patients of them were treated with ventriculo-peritoneal shunts. Four representative cases among them were evaluated by pre- and postoperative polygraphic studies. A polygraphic overnight study includes a monitoring of an intracranial pressure (ICP), electroencephalography (EEG), electrooculography (EOG), respiratory movement and electromyography (EMG). Each data was recorded for the analysis on data recorder using a computer system. A pressure waves (largely B type) appeared accompanied with an apnea at a resting state (so-called sleep) of each patients. An arousal response in EEG was also observed in the raising period of the pressure waves. At the peak respiration was resumed with transient activities in EMG and continued to the disappearance of the pressure wave. Pressure waves were observed frequently and continually in hours in the resting state of these patients. As a result the level of sleep alternated frequently between an awake stage and a stage 1, including extremely rare appearance of stage 2. In short, the level of sleep was frequently interrupted by the appearance of the pressure waves and apneas. Such pathological states of patient's sleep were involved in the entity of the sleep apnea syndrome.(ABSTRACT TRUNCATED AT 250 WORDS)