閉鎖性頭部外傷の脳波—第2編 慢性期における脳波の経時的観察

THE ELECTROENCEPHALOGRAM IN CASES OF CLOSED HEAD INJURY:Part 2. Follow-up study

I．緒言

　第1編^1）において320例の一般的と考えられる頭部外傷患者の慢性期すなわち受傷後1ヵ月ないし12ヵ月の期間における脳波所見を検討し，安静時非賦活脳波においても5％に発作性異常を，18％に持続性異常を認め，かつこれらの異常波の出現率は若年者に高いことを報告した。この320例の一部の39例に対し1ヵ月ないし数ヵ月の間隔で2回ないし数回の脳波検査を行なつたので，本編ではその結果をもととし，前編で多少の疑問を残した境界領域脳波の解釈，外傷より脳波検査までの期間の長短による異常波出現率の変化，さらに頭部外傷慢性期の脳波所見の経時的変化すなわち改善あるいは悪化の可能性について研究した。

Repeated EEG records (average 2.5 times exam-ination between 1 month to 12 monthes after the injury) were evaluated at 39 cases those were in-cluded in the previously reported (Part 1) 320 closed head injury cases.

1) About half of the cases (19/39) showed fluctua-tion of EEG evaluation such as abnormal 4-+on the border-line, on the border-linee-,normal, but no case showed marked change of EEG such as abnormal 4-,normal.

2) No relation was observed between fluctuating tendency of EEG and age or severity of the injury.

3) It was difficult to find easily fluctuating EEG pattern due to insufficient number of the studied case. The fluctuation of the EEG may partly de-pends on the tentative fluctuation of the patients condition.

4) EEG abnormal rate of the all studied case was stable between 1 month to 12 monthes after the injury.

5) From the clinical stand point of view, the first posttraumatic record was on the border-line, repeated EEG examination should he recommended, was ab-normal, there would be very few chance to recover to normal within post-traumatic 12 monthes, and was normal, very seldom may change to abnormal within post-traumatic 12 monthes.