Increased frequency of learning disability in patients with primary progressive aphasia and their first-degree...

Although risk factors for Alzheimer disease have been well studied, much less is known about risk factors for primary progressive aphasia (PPA).

To demonstrate that learning disabilities (LDs) are more common in patients with PPA and their first-degree family members.

Self-report endorsement of an individual and family history of an LD in a sample of 699 subjects from the Northwestern Alzheimer's Disease Center registry. We compared 3 dementia groups (PPA, typical amnestic Alzheimer disease, and the behavioral variant of frontotemporal dementia) and 1 elderly control group. A retrospective medical record review in the PPA probands was used to obtain additional information.

Prevalence of LDs among probands and their first-degree relatives.

The patients with PPA and their first-degree family members had a significantly higher frequency of LD compared with the other dementia groups and the controls. Some of the families of patients with PPA displayed unusual concentrations of LD, especially dyslexia.

These results suggest that LD may constitute a risk factor for PPA, providing additional clues concerning the determinants for the selective vulnerability of the language network in this syndrome.