Dementia with motor neuron disease.

Dementia with motor neuron disease has been described as a new clinicopathologic entity and more than 100 cases have been reported in Japan since 1964. The clinicopathologic criteria in the diagnosis of dementia with motor neuron disease are: (i) frontotemporal lobe-type dementia with insidious onset, mostly in the presenile period; (ii) neurogenic muscular wasting during the course of the illness (amyotrophic lateral sclerosis- or SPMA-like symptoms); (iii) duration from the onset of illness to death of 2-5 years (average, 30.6 months); (iv) both extrapyramidal symptoms and definite sensory deficits are present less commonly; (v) no characteristic abnormalities in the cerebrospinal fluid or electroencephalogram on screening; (vi) no known parental consanguinity or familial occurrence; and (vii) non-specific, mild to slight degenerative changes in the frontotemporal cortex, hypoglossal nuclei and spinal cord, and frequently in the substantia nigra. Dementia with motor neuron disease is characterized by ubiquitin-immunoreactive intraneuronal inclusions in cortical layer II and hippocampal dentate granule cells.