Accuracy of estimation of time-intervals in psychogeriatric outpatients

Accuracy of estimation of time-intervals has received marginal attention in psychogeriatrics. We examined presumed differences in this time measure in participants with dementia (PWD) versus participants without dementia (PWoutD), further subdivided into specific diagnoses and performance subgroups. We also studied its demographic, clinical, and cognitive correlates and predictors. A diagnostic role was hypothesized.

Forty-three individuals (27 PWD: 16 dementia of the Alzheimer's type (DAT), 11 vascular dementia (VaD); 16 PWoutD: 10 major depressive disorder (MDD), 6 normal) were interviewed with the Cambridge Examination for Mental Disorders of the Elderly - Revised (CAMDEX-R) that permits the registration of this time measure. Demographic, clinical, and cognitive data were obtained.

Neither absolute accuracy of estimation of duration of interview nor its transformed logarithm were significantly different between PWD and PWoutD, or between DAT and VaD participants. MDD participants performed significantly poorer than normal and did not differ from PWD, and the PWD relatively better performing subgroup. The logarithm of absolute accuracy of estimation correlated with some clinical and cognitive variables. Only a measure of depression and of impaired judgment could significantly predict it.

The absolute accuracy of estimation of time-intervals did not differ between the major groups and the main diagnoses subgroups. It was associated with a variety of clinical and cognitive measures, and was predicted by the composite constructs of depression and impaired judgment. The diagnostic value of this measure in the psychogeriatric clinic is questionable, and limited to "worried" well individuals.