Cortical and Subcortical Argyrophilic Grains Characterize a Disease Associated With Adult Onset Dementia

Unusual cytoskeleton abnormalities were found in the brains of 28 individuals afflicted with adult onset dementia. Most conspicuous were small spindle-shaped argyrophilic grains loosely scattered throughout the neuropil. Additionally, coiled bodies of silver-stained filaments were encountered, mainly located within the white matter close to the cortical grey matter. Argyrophilic grains and coiled bodies contained dense accumulations of straight filaments with a diameter of about 9 nm. The argyrophilic grains were found in abundance within sector CA1 of the Ammon's horn and layer Pre-beta of the entorhinal region. A slightly less dense scattering of the grains occurred in layer IIIab of the adjoining temporal isocortex, insular cortex and orbitofrontal cortex. The basolateral amygdaloid complex and the hypothalamic lateral tuberal nucleus were the most affected subcortical structures. Deeper brain stem nuclei merely showed a sparse number of grains or were devoid of them. Eighty brains of demented individuals were examined. Forty-eight of them showed the features of Alzheimer's disease and four showed the features of Pick's disease. Twenty-eight cases revealed the abnormalities under consideration. Ten showed exclusively argyrophilic grains and coiled bodies, while 16 also had neuritic plaques, neurofibrillary tangles, and neuropil threads. One of the 28 cases was associated with Parkinson's disease and one showed features of both Parkinson's and Alzheimer's disease. Twenty brains of non-demented individuals of about the same age and devoid or almost devoid of Alzheimer changes were used as controls. None of the control brains showed the presence of argyrophilic grains and coiled bodies. These changes, therefore, are considered the morphological substrate of an unknown disease associated with adult onset dementia.