Presenile dementia with motor neuron disease.

Seventy-one Japanese cases of presenile dementia with motor neuron disease were reviewed. The clinico-pathological features were: (1) progressive dementia with insidious onset, mostly in the presenile period: (2) neurogenic muscular wasting in the course of illness (ALS- or SPMA-like symptoms); (3) duration from the onset of the illness to death: 2-5 years (average 30.6 months); (4) extrapyramidal symptoms and definite sensory deficits are less commonly present; (5) no characteristic abnormalities in the CSF or EEG; (6) no known consanguinity or familial occurrence; (7) non-specific mild to moderate degenerative changes in the fronto-temporal cerebral cortex, hypoglossal nuclei and spinal cord, and frequently in the substantia nigra. The author was interested in discovering whether the frequency and topology of lesions in the brain of patients with presenile dementia and motor neuron disease differed characteristically from the distribution found in cases of Alzheimer's disease, Pick's disease, Creutzfeldt-Jakob disease or progressive subcortical gliosis. Presenile dementia with motor neuron disease might be a new disease entity.