Factorial validation of the Severe Impairment Battery for patients with Alzheimer's disease. A pilot study.

The Severe Impairment Battery (SIB) estimates the cognitive aptitudes and other skills of severely impaired dementia patients. The main objective of this pilot study was to clearly identify the number of factors present in the SIB and to analyze the relationships between the different cognitive domains explored by the SIB and loss of autonomy. We administered the SIB, the Mini Mental State Examination (MMSE) and two scales of dependency to 48 patients with Alzheimer's disease in its late stages. A factorial analysis (Principal Components Analysis) showed a 4-factor solution for the SIB: a cognitive factor, a praxis and visuospatial functions factor, the reactivity to external stimuli factor and the social aptitudes factor. A factorial analysis involving the dependency scales showed a cognitive factor, a dependency and constructional praxis factor, the reactivity to external stimuli factor and the social aptitudes factor. Reactivity to external stimuli and social aptitudes were not significantly correlated to cognitive aspects nor to dependency. The finding of dependency as a factor different from cognitive deterioration suggests that, in setting a treatment strategy for demented patients, attempts should be made to treat dependency in its own right. In addition, since reactivity to external stimuli and social aptitudes are not related to cognitive aspects nor to dependency, these functions should also be encouraged and stimulated.