Presenile non-Alzheimer dementia with motor neuron disease and laminar spongiform degeneration

We describe the clinicopathological findings in three autopsy cases of presenile dementia with motor neuron disease. These patients had a relatively rapid course involving dementia and muscle weakness with a distal pattern of atrophy in the upper extremities. Postmortem examination revealed features of motor neuron disease and spongiform cortical degeneration. The latter change was most marked in the second layer of the frontal or temporal cortex and included minimal to mild neuronal cell loss and mild to moderate gliosis. In this report we relate these patients' laminar spongiform degeneration to three other conditions; frontal lobe dementia, primary progressive aphasia and dementia lacking a distinctive histology. These three conditions and presenile dementia with motor neuron disease may fall within the spectrum of the non-Alzheimer type frontotemporal degenerative dementia.