Clinical and neuropsychological correlates of impaired awareness of deficits in Alzheimer disease and Parkinson disease: A comparative study

Objective: To compare patients with Alzheimer disease (PLD) and Parkinson d isease (PD) with regard to their awareness of cognitive, emotional/social i nteraction, self-care, and motor-related neurologic deficits. Background: U nawareness of deficits, a clinically important symptom, is found in AD. It has been hypothesized to be associated with disruption of frontal-subcortic al circuits but has been little studied in other neurodegenerative disorder s. Because PD has a different anatomic-pathologic substrate, a comparison o f impairment of awareness in AD and PD may shed light on the neural basis o f this phenomenon. Method: Impairment of awareness was measured as the diff erence between patient self-report and caregiver ratings of patient abiliti es on questionnaires tapping cognitive, emotional/social interaction, self- care, and motor function. These "discrepancy scores" were then compared bet ween the two diagnostic groups and examined in relation to selected neurops ychological test data. Results: In general, both AD and PD patients rate th emselves as being less impaired than do their caregivers. The two diagnosti c groups, AD and PD, differ significantly, however, on awareness discrepanc y measures in the cognitive domain. m their ratings of patient cognitive sk ills, AD caregivers rate patients as significantly more impaired than patie nts rate themselves, whereas PD caregivers and patients do not differ signi ficantly on these ratings. Impaired awareness in PD but not in AD is associ ated with poorer overall cognitive function and performance on tests measur ing memory, attention: and constructional ability. Conclusions: Both AD and PD patients display impaired awareness of deficits in multiple domains, in cluding motor-related neurologic function. Parkinson disease patients with comparatively intact cognitive function display relatively preserved awaren ess of motor and other deficits.