Pathology of motor neurons in amyotrophic lateral sclerosis with dementia.

One type of motor neuron disease (MND) associated with dementia is well known for the fact that it displays atrophy of the frontal and temporal lobes, neuronal loss and sponginess of the superficial layers of the cortex, and subcortical gliosis (so-called Mitsuyama type). In an attempt to determine characteristics of the pathology of motor neurons, three cases of MND with dementia were examined and compared with 16 cases of sporadic classical amyotrophic lateral sclerosis (ALS) with light and electron microscopes. All these cases with dementia showed loss of motor neurons, chromatolysis, spheroids, and Bunina bodies. Quantitative analyses of the 5th lumbar anterior horns showed no significant differences in incidences of chromatolysis and Bunina bodies between cases with and without dementia. Ultrastructures of the anterior horns were essentially identical in both groups. Therefore, the pathology of motor neurons at least in one type of MND with dementia seems to share common features with that in sporadic classical ALS without dementia.