Copy task performance and urinary incontinence in Alzheimer's disease

The relationship between behavioral symptoms and cognitive impairment in Alzheimer's Disease (AD) is only poorly understood. The aim of the present study was to examine cognitive correlates of urinary incontinence in AD. Although incontinence is generally accepted as an accompaniment of AD, it was our clinical impression that it correlated poorly with global measures of cognitive impairment. A retrospective pilot study of 17 incontinent demented patients and 17 continent patients, matched for age, sex, and total score on the Folstein Mini-Mental Status Exam (MMSE), revealed a striking association between an inability to do a copy task and urinary incontinence. A prospective study confirmed this finding in a sample of 45 patients meeting DSMIII-R diagnostic criteria for dementia, probable Alzheimer's disease. The 17 incontinent patients did not differ from the 28 continent patients in age, sex distribution, or total score on the MMSE. However, the incontinent subjects scored significantly lower on a cube copying task. Qualitative analysis revealed that the drawings by incontinent patients showed features comparable with those observed in the drawings by patients with right-sided parietal lesions, in particular, poor representation of perspective and spatial orientation. Further investigation of the relationship between copying performance and incontinence may have implications for understanding the cortical mechanisms of urinary continence. The present results also underscore the limitations of the MMSE as a measure of dementia severity and suggest there are areas of cognitive ability which are inadequately assessed by MMSE but which may be of major important in understanding the loss of functional skills in the dementing patient.