To describe the cognitive and neuropsychiatric features of an Alzheimer’s Disease (AD) Peruvian cohort

The Peruvian admixed population is comprised of ~80% of Amerindian ancestry. The prevalence of dementia in Peru is estimated at 7% among people over age 65, with 56% of them meeting clinical criteria for AD. We have ascertained a cohort of AD cases and cognitively intact controls for genetic studies.

Participants have been recruited using community outreach ascertainment strategies and hospital-based recruitment in Lima. Cases were assessed by neurologists following NINCDS/ADRDA criteria and completed comprehensive neurocognitive and functional assessments. Controls were screened using the MMSE,Clock Drawing Test and Functional activities questionnaire.

Our sample set consists of 116 AD cases (4 familial cases) and 182 controls who were enrolled beginning May 2019 through August 2021.For AD cases:67.2% were female, mean age at examination was 76.8± 8.78, mean age at onset was 71.81±8.76 with an average of 10.13 ±4.79 years of education. Cases were classified as possible AD (76.7%) and probable AD (23.3%).The mean MMSE score was 17.3± 4.9 and Addenbrookes Cognitive Assessment average score was 38.7± 22.4. Severity of dementia were assessed by the Clinical Dementia Rating Scale (CDR=3 for 36.4%,CDR=2 for 33.8%,CDR=1 for 22.1% and CDR=0.5 for 7.8%). Based on NPI-Q,the most frequent neuropsychiatric symptoms were irritability (65%), delusions (56%) and apathy (55%). For controls: 68.1% were female,mean age at examination was 73.42±6.51,and average of 11.95±4.41 years of education. There a consistently higher level of education among controls compared with cases (X², p=0.004).

The clinical features of the AD cohort in the Peruvian population are like to other AD populations. There is a significantly higher level of education in controls, supporting that this finding is not population specific. The main neuropsychiatric symptoms are irritability, delusions, and apathy consistent with the predominance of moderate to severe dementia.