# Latent classes and progression of Mini-Mental State Examination scores in young-onset dementia: Data from the Swedish Dementia Register

## TL;DR

The study finds that young-onset dementia shows diverse cognitive decline patterns, emphasizing the need for personalized care.

## Contribution

Identifies five distinct cognitive decline classes in young-onset dementia using growth mixture models.

## Key findings

- Five latent classes of cognitive decline were identified in young-onset dementia patients.
- Classes differed in baseline MMSE scores, decline rates, and demographic factors.
- Results suggest young-onset dementia is as heterogeneous as later-onset dementia.

## Abstract

Studies have shown significant heterogeneity in the longitudinal progression of dementias, including Alzheimer's disease. Growth mixture models have detected up to 4 classes that differ in both baseline Mini-Mental State Exam (MMSE) and rate of decline over time. Most analyses focus on adults over age 65 and investigate group differences in demographic and health variables.

The current analysis focused on adults with young onset dementia (YOD) and examined the role of demographic and support variables in differentiating latent classes of longitudinal progression of cognitive status.

Sample included 1025 adults (55% women) registered in the Swedish Dementia Register prior to age 65 with at least 3 registrations. Age at baseline was 38 to 64 (mean = 59.3, SD = 4.1); follow-up duration ranged from 1 to 12 years (mean = 4.6, SD = 2.0).

Growth mixture models identified 5 classes: high baseline MMSE and moderate decline over time (48.5%), intermediate baseline MMSE and moderate decline (34.5%), high baseline MMSE and steep decline (13.4%), low baseline and generally stable MMSE over time (2.6%), and high baseline with precipitous decline (1.0%). Latent classes differed in age at diagnosis, diagnostic categories, number of medications, and having home help services.

Results highlight that YOD is just as heterogeneous as later onset dementia; therefore, it is vital that people with YOD get early diagnosis and a case manager to help identity and meet their individual needs.