[Frontal type dementia and amyotrophic lateral sclerosis. 3 cases with (HmPAO Tc99m) single-photon emission tomography study].

Three cases of rapid onset neuropsychological frontal dementia preceded the development of sporadic amyotrophic lateral sclerosis by 12 to 24 months. HmPAO Tc99m scintigraphy demonstrated hypoactivity in the cortex, predominantly in the frontal region. Three hypotheses are discussed: 1) coincidence between two degenerative diseases, Alzheimer's disease or Pick's disease and ALS; 2) an amyotrophic form of Creutzfeld Jakob disease; 3) pre-senile dementia associated with a motoneuron disease, a clinical pathology entity recently described by Mitzuyama.