Relationships Between Behavioral Syndromes and Cognitive Domains in Alzheimer Disease: The Impact of Mood and Psychosis

• Published in: The American journal of geriatric psychiatry 2012-11, Vol.20 (11), p.994-1000
• Main Authors: Koppel, Jeremy, M.D, Goldberg, Terry E., Ph.D, Gordon, Marc L., M.D, Huey, Edward, M.D, Davies, Peter, Ph.D, Keehlisen, Linda, M.A, Huet, Sara, B.S, Christen, Erica, M.S, Greenwald, Blaine S., M.D
• Format: Article
• Language: English
• Subjects: Aged; Aged, 80 and over; Alzheimer Disease - diagnosis; Alzheimer Disease - epidemiology; Alzheimer Disease - psychology; Behavioral disturbance; cognition; Cognition Disorders - diagnosis; Cognition Disorders - epidemiology; Cognition Disorders - psychology; Cohort Studies; Comorbidity; Cross-Sectional Studies; dementia; Female; Health Surveys; Humans; Internal Medicine; Male; Mental Disorders - diagnosis; Mental Disorders - epidemiology; Mental Disorders - psychology; Mental Status Schedule - statistics & numerical data; Middle Aged; Mood Disorders - diagnosis; Mood Disorders - epidemiology; Mood Disorders - psychology; Neuropsychological Tests - statistics & numerical data; New York; Psychometrics - statistics & numerical data; Psychosis; Psychotic Disorders - diagnosis; Psychotic Disorders - epidemiology; Psychotic Disorders - psychology; Reproducibility of Results; Statistics as Topic; Syndrome
• ISSN: 1064-7481; 1545-7214
• DOI: 10.1097/JGP.0b013e3182358921

Objectives Behavioral disturbances occur in nearly all Alzheimer disease (AD) patients together with an array of cognitive impairments. Prior investigations have failed to demonstrate specific associations between them, suggesting an independent, rather than shared, pathophysiology. The objective of this study was to reexamine this issue using an extensive cognitive battery together with a sensitive neurobehavioral and functional rating scale to correlate behavioral syndromes and cognitive domains across the spectrum of impairment in dementia. Design Cross-sectional study of comprehensive cognitive and behavioral ratings in subjects with AD and mild cognitive impairment. Setting Memory disorders research center. Participants Fifty subjects with AD and 26 subjects with mild cognitive impairment; and their caregivers. Measurements Cognitive rating scales administered included the Mini-Mental State Examination; the Modified Mini-Mental State Examination; the Boston Naming Test; the Benton Visual Retention Test; the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychology Assessment; the Controlled Oral Word Test; the Wechsler Memory Scale logical memory I and logical memory II task; the Wechsler Memory Scale-Revised digit span; the Wechsler Adult Intelligence Scale-Revised digit symbol task; and the Clock Drawing Task together with the Clinical Dementia Rating Scale and the Neuropsychiatric Inventory. Results Stepwise regression of cognitive domains with symptom domains revealed significant associations of mood with impaired executive function/speed of processing (Δ r2 = 0.22); impaired working memory (Δr2 = 0.05); impaired visual memory (Δr2 = 0.07); and worsened Clinical Dementia Rating Scale (Δr2 = 0.08). Psychosis was significantly associated with impaired working memory (Δr2 = 0.13). Conclusions Mood symptoms appear to impact diverse cognitive realms and to compromise functional performance. Among neuropsychological indices, the unique relationship between working memory and psychosis suggests a possible common underlying neurobiology.