Acquired mild cognitive impairment in adults with Down syndrome: Age-related prevalence derived from single point assessment data normed by degree of intellectual disability.

Chris Oliver,Sarah Ball,Dawn Adams,Karen Dodd,Anthony J Holland,Janet Carr,Stephanie S G Brown

doi:10.1002/gps.5674

Abstract

BackgroundIndividuals with Down syndrome (DS) are at significant risk for early onset Alzheimer's disease (AD), likely due to the triplication of genes on chromosome 21 that facilitate AD neuropathology. To aid the effective early diagnosis of dementia in DS, we demonstrate the strategy of using single point assessment of cognitive performance with scoring normed for degree of intellectual disability to generate age related prevalence data for acquired mild cognitive impairment (AMCI).MethodsFour hundred and twelve adults with DS were assessed using the Neuropsychological Assessment of dementia in adults with Intellectual Disability. Normative data, banded by degree of intellectual disability, allowed identification of AMCI by atypical deviation from expected performance.ResultsAMCI was evident in approximately 20% of adults with DS aged 40 and under, 40% aged 41–50 and 45% aged 51 and over. Relative risk increased significantly in those aged 46 and over. Analysis of prevalence by 5‐year age bands revealed two peaks for higher prevalence of AMCI.ConclusionsPsychometric data indicate single point assessment of AMCI is possible for the majority of adults with DS. Two peaks for age‐related prevalence of AMCI suggest the risk for onset of AD conferred by trisomy of chromosome 21 is moderated by another factor, possibly ApoE status.

Highlights

Down syndrome (DS) is a neurodevelopmental disorder that results from full or partial trisomy of chromosome 21 with subsequent gene overexpression
We analysed a large neuropsychological assessment dataset collected across cohorts of adults with DS using a novel strategy for identifying abnormally poor performance on tests
NAID scores at subscale and domain level show a decline with age as might be predicted given the increasing prevalence of dementia with age in adults with DS.[27]

Summary

Introduction

Down syndrome (DS) is a neurodevelopmental disorder that results from full or partial trisomy of chromosome 21 with subsequent gene overexpression. Individuals with Down syndrome (DS) are at significant risk for early onset Alzheimer's disease (AD), likely due to the triplication of genes on chromosome 21 that facilitate AD neuropathology. To aid the effective early diagnosis of dementia in DS, we demonstrate the strategy of using single point assessment of cognitive performance with scoring normed for degree of intellectual disability to generate age related prevalence data for acquired mild cognitive impairment (AMCI). Normative data, banded by degree of intellectual disability, allowed identification of AMCI by atypical deviation from expected performance. Conclusions: Psychometric data indicate single point assessment of AMCI is possible for the majority of adults with DS. Two peaks for age‐related prevalence of AMCI suggest the risk for onset of AD conferred by trisomy of chromosome 21 is moderated by another factor, possibly ApoE status

Methods

Results

Conclusion