[Dementia and disturbance of consciousness in thalamic degeneration].

A 53-year-old male with thalamic degeneration is presented. He had double vision, cerebellar signs, and pyramidal and extrapyramidal tracts signs in addition to hypersomnia, decrease in spontaneity and attention, and impairment of memory as psychic symptoms. These signs and symptoms were progressive, and he subsequently developed akinetic mutism and died of pneumonia 17 months after the onset of the disease. His clinical diagnosis was considered as Gerstmann-Sträussler syndrome due to progressive dementia, cerebellar signs and the other signs mentioned above. The postmortem pathological investigations, however, revealed thalamic degeneration. The pathological observations showed marked loss of nerve cells and glial proliferation in the medial and anterior nuclei of thalamus. The same pathological changes were more or less demonstrated in the pulvinar, the periaqueductal gray matter of midbrain, inferior olivary nucleus, the medial parts of globus pallidus, the substantia nigra and the dentate nucleus. In the early stage of the clinical course, it was difficult to know whether the main symptoms were caused by dementia or by the disturbance of consciousness. Retrospective considerations, however, showed that dementia had appeared at first, and subsequently the disturbance of consciousness had joined. As the result, it seems that they finally caused akinetic mutism. It is known as thalamic dementia that in the cerebrovascular disease the lesions in the medial and anterior parts of bilateral non-specific thalamic nuclei cause dementia.(ABSTRACT TRUNCATED AT 250 WORDS)