Argyrophilic grains: A distinct disease or an additive pathology?

Background: Argyrophilic grains (AG) are silver-positive spindle-shaped lesions found at postmortem. Their significance is controversial. Objective: To determine clinical correlates of AG and MRI patterns of atrophy that could allow premortem recognition of this pathology. Methods: Cases with AG were identified from a longitudinal study of aging and dementia. Clinical features were compared between subjects with and without dementia. Voxel-based morphometry (VBM) was used to assess patterns of grey matter atrophy in subjects compared to controls. Whole brain volumes (WBV) were compared across groups. Results: Twenty-two cases (14 females; median age at death of 90 years; range: 70-101) with AG were identified. Eight of the 22 were demented. Those with dementia had higher Braak (p = 0.02) and lower Mini-Mental State Examination (MMSE) (p = 0.002). VBM demonstrated hippocampal atrophy in those with dementia (N = 3) but no atrophy in those without (N = 9). There was no difference in WBV between groups. Conclusion: AG is a feature of old age commonly occurring in non-demented subjects. In this age group, the presence of AG may reduce the threshold for dementia.