正常圧水頭症における精神症状の神経生理学的研究—手術適応の選択におけるContingent negative variationの応用

Neurophysiological Study on Psychiatric Symptoms in Normal Pressure Hydrocephalus:Clinical evaluation by the contingent negative variation

I．緒言

　正常圧水頭症（normal pressure hydrocephalus, NPH）にみられる精神症状は，その三主徴のひとつとして診断上重要な症状である^{1,9,13,20,25-27,46）}．その症候は，記憶障害とslowness and paucity of thought andaction, laek of spontaneity and initiative, faulty concentration, distractability, lack of interest, apathy, inertia^1）等と記述される無為的状態^9）とが主体となっているが，このような状態はbehavioralにはmood depressionと類似しており，なかでもdementiaにdepressionが伴っているものやdepressive pseudodementiaとの鑑別が必要であることがしばしば指摘されてきた^{1,3,9,25,34,37,38,40,45）}．

Changes in the contingent negative variations (CNV_s) were investigated in 15 patients with the normal pressure hydrocephalus (NPH) caused by the subarachnoid hemorrhage. CNV_s were recorded by S₁ (WS, click)-S₂ (IS, electrical stimulation of the median nerve with the intensity 10V above the motor threshold)-R (button pressing) and S₁ (CS, click)-S_2'(UCS, painful electrical stimulation of finger tip) paradigms. Same recordings were also carried out in 17 almostly same aged patients with brain atrophy and 13 normal subjects as control.