Variation in sources of clinician-rated and self-rated instrumental activities of daily living disability

Background. It is unclear how well self-reports and clinician ratings of performance in the instrumental activities of daily living (IADLs; household maintenance tasks) correspond and why they may differ. Methods. We assessed clinician-rated IADL performance using an occupational therapy protocol, the Assessment of Motor and Process Skills (AMPS). AMPS and self-rated IADL disability were compared in two groups of nondemented elderly persons without ADL limitation: a group with functional limitation only (self-reported difficulty in some area of upper or lower body function, n = 139) and a group that reported functional limitation plus IADL disability (difficulty in at least one IADL task, n 49). Occupational therapists were blind to self-reports, and all assessments were conducted in respondent homes. Results. Self-rated IADL disability was significantly associated with the AMPS motor skill score (r=-.34,p < .001), but the motor skill score was only moderately sensitive (61%) and specific (67%) in identifying self-rated disability. In adjusted logistic regression models, clinician-rated performance and self-rated IADL disability shared some physical predictors, but only clinician-rated performance was related to cognitive status. AMPS process skill scores did not relate to self-rated IADL disability or physical or cognitive status. Conclusions. In this sample of older adults without dementia or ADL disability, clinician ratings of IADL motor skill and self-rated IADL disability were correlated. Physical deficits appear to be more salient in self-ratings than is cognitive ability, because cognitive ability (in particular, verbal fluency) was associated only with clinician-rated 1ADL performance.