Temporal lobe pathology in amyotrophic lateral sclerosis. Do amyotrophic lateral sclerosis and Alzheimer's disease share a common etiological factor?

An autopsy study was performed on temporal lobe samples from 20 non-demented patients with amyotrophic lateral sclerosis (ALS), 17 age-matched non-demented controls and 4 Alzheimer's disease (AD) patients. Formalin fixed, paraffin embedded sections from the hippocampus with adjacent parahippocampal gyrus and from the superior temporal gyrus were stained with conventional and immunohistochemical stains. Immunohistochemical staining for the A4 protein was enhanced by pretreatment with 0.25% pepsin before 100% formic acid. The incidence and severity of AD-like pathological changes were similar in ALS patients and non-demented controls. In both groups, pathological changes increased with age. This study does not support the hypothesis that ALS and AD share an etiopathogenetic background.