視床性痴呆と無動性無言

THALAMIC DEMENTIA AND AKINETIC MUTISM

I．はじめに

　Akinetic Mutism （AM）は1941年Cairns^1）らによつて記された意識陣害の特別な型である。彼らの報告によると，患者は眼球運動の他は随意運動は全くできず話せない状態を示した。本邦においてもその臨床病理学的報告は多数あり，その原疾患として循環障害，炎症，腫瘍，外傷および中毒が挙げられている。本報告では，すでにその疾患的位置づけについて報告した^6）初老期の視床性痴呆でみられたAMに焦点をしぼり，AM発症の機構を形態学的側面から追求し，視床性痴呆とAMの関係を考察する。

A clinico-pathological study on an unclassified case of presenile degeneration of the CNS was reported, which showed dementia and terminal akinetic mutism.

Memory disturbance, impaired judgement and irritability were manifested in a 61-year-old female and akinetic mutism gradually predominated. In this condition continuous hyperthermia, sweating and incontinence were observed, while deglutition and mastication were well preserved. Neuro-logically, rigidity of the upper limbs and hypotonic lower limbs in a characteristic contracted posture, hand tremor, oil face and Babinski sign were re-vealed. Neuronal loss and reactive gliosis were found in the globus pallidus, especially, in the inner segment, and in the zona compacta of the substantia nigra. The mediodorsal nucleus, the centromedian nucleus, nucl. parafascicularis and the anterior nucleus were severely affected in the thalamus. The reticular formation of the medulla oblongata and the pons were involved with eminent gliosis. Anatomical and pathophysiological consid-eration suggested that lesions not only in the thalamus but also in the globus pallidus play a great role for manifestation of akinetic mutism. In the literature as well as in the present case, thalamic dementia develops often into akinetic mutism and pathological localization pattern in the thalamus of these two conditions has a remarkable resemblance. These evidences show that thalamic dedentia and akinetic mutism may occur in the same pathomorphological substratum. The differ-ence between these clinical manifestations seems to relate to the extension and tempo of the patho-logical process. One must also consider involve-ment of the reticular formation, i. e., the center of consciousness, in akinetic mutism.