脳波の総合的観察からみたCardiazol賦活の臨床的意義

ON THE CLINICAL SIGNIFICANCE OF METRAZOL (CARDIAZOL)-ACTIVATED EEG

I．はじめに

　臨床被は「ひと」の脳の直接的な機能検査として，てんかんを初めとする中枢神経疾患の診断に有用性を高めつつあるが，一面これに伴う幾多の問題が新たに解決をせまられている。賦活法における結果の判読と臨床的意味づけも，その最も重要なもののひとつといえよう。

　最近のroutine workとしての脳波検査は，はじめ閉眼安静時の脳被を記録し，これに光刺激や過呼吸のような無害で容易な賦活を加えて終る。ここまでの検査で脳波判定上「正常・異常の境界」となつた症例に，潜在する異常性をひきだすため，さらに薬物による賦活法が行なわれる。Cardiazol賦活法はこうした場合，てんかん群を非てんかん群，ことに神経症群ならびに正常群から鑑別する有力な賦活法として，最もひろく用いられてきた。

To make more available the Metrazol activation in the clinical EEC. examination, the author tried to know, more precisely, the characteristics of the pati-ent shown the low Metrazol threshold. As the one of the methods for this purpose, she investigated the relation "Metrazol threshold" and the several findings of EEC which recorded before this activation and some somatic features.

This observations covered a total of 253 patients who were selected from among the patients examined in our clinical EEG laboratry in 1962-1963. They had recorded at the resting state, under the photic stimulation and hyperventilation; and then they were classified electroencephalograpoically as "bordealine" before the Metrazol activation.

They were divided into 8 groups according to their clinical and electroencephalographical diagnosis as generalized epilepsy, portial epilepsy, suspected epi-lepsy, head injury, organic or functional cerebral disorders, psychosis, neurosis, and normal.

Every patient was slowly injected intravenously 100 mg par minute of 2% Metrazol.

"Threshold" was measured at the point of the total dosage of Metrazol indused the certain changes in the EEG: that is diffuse high voltage single slow wave, high voltage slow wave burst, spike and wave com-plex, and clinical seizure. Results of this report were dealing with the general responses under 300 mg of Metrazol, excluding the cases shown partial resposes.

Results: 1) In general, the ratio of the cases shown "lower Metrazol" was higher among the cases of records with "higher voltage and largger amount of slow waves" at the resting record. This relation was remarkable in the group of head injury. Amount and duration of a waves and fast waves at resting record scaresely had relation with "threshold".

2) Photic driving by flicker before Metrazol activa-tion had no characteristic correlation with "threshold".

3) The cases shown remarkable "build up" of slow waves by hyperventilation were included in the two groups; the one showed very low Metrazol threshold and the other did relatively higher threshold, then the former belonged to the generalized epilepsy group and it's threshold was the lowest even in this epilepsy group, while the latter belonged to the organic or functional cerebral disorders. In the cases of head injury, generally, only slightly "build up" by hyperventilation was shown with or without low Metrazol threshold.

4) The mod of changes of EEG during Metrazol injection was divided into the two groups; the first that the paroxysmal waves burst out during injection without remarkable change previously, and the second that slow waves increase step by step and then the paroxysmal waves appear. The first type was oberved at the highest ratio in the generalized epilepsy group, while the second was observed at the highest ratio in the head injury group.

5) Forty cases were picked up at random from among the patients who activated by Metrazol, and tested the reaction of Mecholyl. Among the cases of "low Metrazol threshold", the ratio of the fitter-mediate type was lower, while this reaction type occupies great ratio in normal adults.

Based on those results, it may be concluded that the "low Metrazol threshold" indicates weakness or unstability of subcortical structures, as far as the general responses to Metrazol is concerned.