小脳性言語障害の臨床—その歴史的背景と新しい局在論

CEREBELLAR DYSARTHRIA : HISTORICAL BACKGROUND AND NEW CONCEPT OF FUNCTIONAL LOCALIZATION

I．はじめに

　小脳性言語障害の初めての記載は1877年に行われたCharcotによるdisseminated sclerosisの紹介の中に現われる^8）。Babinskiが1899年に発表したasynergiecérébelleuseの観察記録にも言語の障害を紹介している^23）。その後André-Thomas （1900），Gordon Holmes（1922）^17）らにより古典的小脳症候学は完成される。しかしながらdysarthriaというwordがGarrison’sHistory of Neurology^24）に1度しか出てこぬようにdysarthriaそのものがneurologistのtargetになることは少なかつた。そして，小脳における言語機能局在論もneurologistに十分な興味を持たれぬまま現在にいたるまで，神経学の教科書には曖昧な記載が多い^28,32）。まして，魅力あるStenver’s hypothesis^35）などは再評価されることはなかつた。

　脳神経外科医は小脳橋角部腫瘍摘出に際し，Drake（1967），Kurze （1969）らの手技が導入されるまでCus—hingの原法に従い，小脳半球をuncappingし^31），また第4脳室腫瘍へのapproach　としてinferior vermisを切開し，いずれも術後患者の言語に異常の生じないことを昔から知つているはずである。華かな神経症候学の中で言語がとり残された理由の一つは言語の客観評価・記録の困難性であろう。著者は新しい言語の客観評価法を利用し，小脳の言語機能の局在性に関し臨床面から検索を試み，文献上の論議を整理した。

In general neurologist did not show interest about cerebellar dysarthria, since Babinski or Holmes had recorded brilliantly about cerebellar symptoms. We have had very few opportunities to investigate the functional localization of cerebellar dysarthria. In this paper, 36 neurosurgical patients mainly, having apparent cerebellar lesions were examined for cere-bellar dysarthria. As the methods for the estima-tion of speech disturbance, the analysis of speech oscillograph and the speech impression by modified Darley's speech dimentions were used. These methods for the objective estimation of dysarthria were quite available for my cases. Group I of 15 patients with apparent dysarthria had almost same lesion on mesial superior cerebellar surface, indicat-ing superior vermis and bilateral pars interme-dia of superior surface on zonal concept. Group II of 21 patients without dysarthria showed the lesion in rt or It-lateral hemisphere and inferior vermis. Speech construction in cerebellar dysarthria was shown by speech oscillograph clearly. Their lesion in cerebellum was well identified by operative and neuroradiological findings. The area associated with the lesion of group I was well located and was suggested for the functional localization of speech.

New clinical entities about speech"cerebellar mutism"was presented in this paper. Three cases with vermian tumor showed so-called mute state after operation. Complete separation of cerebellar hemisphere, superior and inferior vermis were per-formed surgically in order to remove the lesion of cerebellum.

Duration of"cerebellar mutism"phase was re-corded for 2-6 months and afterward apparent dysarthric phase was occured. The author would postulate the new concept of the functional locali-zation for cerebellar dysarthria and suggested significant anatomical interconnection between the cerebellar hemisphere and the integration of speech.

The historical reviews for cerebellar dysarthria were made in detail.