Cognitive Profiles on the Severe Impairment Battery Are Similar in Alzheimer Disease and Down Syndrome With Dementia

Dick, Malcolm B. PhD^*; Doran, Eric MS^†; Phelan, Michael PhD^‡; Lott, Ira T. MD^†,§

^*Alzheimer’s Disease Research Center, Institute for Memory Impairments and Neurological Disorders (MIND)

Departments of^†Pediatrics

^§Department of Neurology, School of Medicine

^‡Department of Statistics, University of California, Irvine (UCI), Irvine, CA

Supported by the National Institute on Aging (NIA) (Grant P50 AG016573 to the University of California at Irvine, Alzheimer’s Disease Research Center, and Grant AG-21912 to the University of California, Irvine; PI: I.T.L.), the National Institute of Child Health and Human Development (NICHD) (Grant HD-065160 to the University of California; PI: I.T.L.), and the National Center for Research Resources (NCRR) and the National Center for Advancing Translational Sciences (NCATS) (Grant UL1 TR000153 to the University of California, Irvine, Institute for Clinical and Translational Science).

The authors declare no conflicts of interest.

Reprints: Malcolm B. Dick, PhD, Alzheimer’s Disease Research Center, Institute for Memory Impairments and Neurological Disorders (MIND), University of California, Suite #1100, Gottschalk Medical Plaza Bldg., Irvine, CA 92697-4585 (e-mail:[email protected]).

Alzheimer Disease & Associated Disorders30(3):p 251-257, July–September 2016. |DOI:10.1097/WAD.0000000000000132

Abstract

Previous research has revealed similarities in the neuropathology, clinical presentation, and risk factors between persons with Alzheimer disease from the general population (GP-AD) and those with Down syndrome (DS-AD). Less is known, however, about the extent of similarities and differences in the cognitive profiles of these 2 populations. Fifty-one moderate to severely demented GP-AD and 59 DS-AD individuals participated in this study which compared the cognitive profiles of these 2 populations on the Severe Impairment Battery (SIB), controlling for sex as well as level of functional ability using a modified version of the Bristol Activities of Daily Living Scale. Overall, the neuropsychological profiles of the higher-functioning individuals within the DS-AD and advanced GP-AD groups, as represented by mean difference scores on the SIB as a whole and across the 9 separate cognitive domains, were very similar to one another after adjusting for sex and functional impairment. To our knowledge, this is the first study to directly compare the cognitive profiles of these 2 populations on the SIB. Findings suggest that the underlying dementia in GP-AD and DS-AD may have corresponding and parallel effects on cognition.