Naturalistic action impairments in dementia

Neuropsychologists are often consulted to make recommendations regarding the functional abilities of dementia patients, however, little is known about naturalistic action deficits in this population. Several accounts of action impairment have been set forth in the literature which explain action errors within in; the context of specific cognitive deficits, including executive dysfunction (Norman & Schallice, 1986; Fuster, 1980; Sirigu et al., 1995) and semantic knowledge degradation (DeRenzi & Lucchelli, 1988). In addition, a more recent theory suggests limitations in cognitive resources or attentional capacity may best account for naturalistic action impairment and limitations in awareness of errors among individuals with neurological damage or disease (Schwartz et al., 1998). The present study was designed to explore action impairments among a sample of dementia participants (n = 56) grouped according to their relative impairment in executive functioning and semantic knowledge. All participants were administered the Naturalistic Action Test (Schwartz et al., 1998), which allows for the assessment of specific errors of action and awareness of these errors. Results demonstrated few between group differences on measures of errors or awareness. By contrast, error profiles were strikingly similar across the experimental groups. Environmental factors and task demands significantly influenced the type and frequency of errors across all groups. With respect to awareness of errors, there were no significant between group differences, although level of awareness was influenced by error type, with all subjects demonstrating greater awareness for substitution errors as compared to omissions and sequencing errors. Taken together, the findings of the present study reject deficit-based accounts for naturalistic action impairment and error awareness in dementia. The results are discussed as support for the limited resource theory of naturalistic action impairment.