Dementia accompanying motor neuron disease--7 cases.

Seven typical cases of dementia with motor neuron disease (D-MND) are reported. Among 1,000 dementia cases, D-MND was more frequent than Pick's disease, Lewy body disease or Creutzfeldt-Jakob disease. D-MND accounted for 30.4% of all forms of frontal lobe dementia (FLD) including FLD and Pick's disease. These data support that this combined syndrome may be more frequent than previously reported. As the subcortical neuropathology of D-MND is identical with MND, D-MND is rather the cortical manifestation of MND than a new disease entity.