Abstract
Orientation to time and place is frequently assessed in conditions such as Alzheimer's disease (AD). Despite the ubiquitous nature of orientation screening in mental status examinations, relatively little is known about the psychometric properties of orientation subscales. This article seeks to provide detailed psychometric information about the orientation items on the Mini Mental State Examination (MMSE) in individuals with AD. Orientation responses from 1,238 patients with AD (mean age = 75.5 years, SD = 8.4, range = 39 to 94) were examined within an item response theory (IRT) framework. Responses revealed that orientation items on the MMSE functioned differently across the spectrum of cognitive ability, with spatial orientation items tapping the breadth of cognitive impairment better than temporal items, which tended to have overlapping properties. Key clinical implications such as choosing appropriate items for different clinical purposes are highlighted.