Prospective neuropsychological assessment of nondemented patients with biopsy proven senile plaques

Senile plaques are characteristic of Alzheimer's disease but also occur as an age-related change in some neurologically normal individuals at autopsy. The significance of these ''incidental'' senile plaques, with regard to the development of dementia, is unknown and cannot be assessed by postmortem studies. Patients with biopsy proven senile plaques offer an important opportunity for prospective followup. We identified senile plaques in temporal lobectomy specimens, removed in the surgical treatment of intractable epilepsy, from 11 patients. Review of preoperative neuropsychological test results showed no suggestion of dementia in any of the patients with senile plaques and no significant difference compared with controls. Postoperative followup ranged from 2 to 7 years (mean, 3.7 yr). There was no evidence of generalized cognitive deterioration in any of the study patients. These findings indicate that an abundance of senile plaques may be present without associated dementia and without cognitive deterioration for at least several years.