Determinants of functional abilities in dementia.
OBJECTIVE
To determine the extent to which selected variables within demographic, psychometric, and memory domains can predict functional abilities in dementia.


METHODS
Hierarchical regression analyses were employed to predict functional abilities, while controlling for disease severity, using the Mini-Mental State Exam (MMSE).


METHODS
A total of 2368 inhabitants of Kungsholmen parish in Stockholm, Sweden, aged 75 years of age or older. Eighty-one subjects with confirmed dementia (MMSE, M = 17.9; SD = 5.26) were selected from the study population. The mean age was 84.5 years (SD = 5.58), and 72% were female.


METHODS
Participants received a battery of standardized neuropsychological instruments and selected experimental tasks that measured visuospatial ability as well as primary and episodic memory. Self-care was assessed using the Katz index of activities of daily living (ADL); instrumental activities of daily living (IADL) were assessed through the primary caregiver, who responded to questions related to functional competence of the participant.


RESULTS
Hierarchical regression procedures revealed that disease severity was the strongest predictor of ADL and IADL performance. Controlling for disease severity, a measure of visuoperception (Poppelreuter's figures) also made a significant contribution to the explanatory variance in both ADL and IADL function. Beyond disease severity and visuoperception, years of schooling and disease duration were marginally predictive of IADL performance.


CONCLUSIONS
It is possible to predict functional abilities in dementia on the basis of individual difference variables. Multiple variables were initially correlated with ADL and IADL performance; however, after controlling for disease severity, visuoperception was the only predictor of ADL scores. In addition to visuoperception, IADL scores were also marginally predicted by education and disease duration. These findings highlight the importance of peripheral sensory processes in adaptive function in dementia. They also suggest that although many variables may be correlated with functional ability, their explanatory role, particularly with regard to self-care skills, is diminished in the presence of the disease.
Hill
R D
RD
Stockholm Gerontology Research Center, Karolinska Institute, Sweden.
Bäckman
L
L
Fratiglioni
L
L
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D003704:Dementia / Q000503:physiopathology* / Q000523:psychology*; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D011594:Psychometrics; D012044:Regression Analysis; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014796:Visual Perception