Reliability and validity of the Severe Impairment Battery, short form (SIB-s), in patients with dementia in Spain

People with progressive dementia evolve into a state where traditional neuropsychological tests are not effective. Severe Impairment Battery (SIB) and short form (SIB-s) were developed for evaluating the cognitive status in patients with severe dementia. To evaluate the psychometric attributes of the SIB-s in patients with severe dementia. 127 institutionalized patients (female: 86.6%; mean age: 82.6 ± 7.5 years-old) with dementia were assessed with the SIB-s, the Global Deterioration Scale (GDS), Mini-Mental State Examination (MMSE), Severe Mini-Mental State Examination (sMMSE), Barthel Index and FAST. SIB-s acceptability, reliability, validity and precision were analyzed. The mean total score for scale was 19.1 ± 15.34 (range: 0-48). Floor effect was 18.1%, only marginally higher than the desirable 15%. Factor analysis identified a single factor explaining 68% of the total variance of the scale. Cronbach's alpha coefficient was 0.96 and the item-total corrected correlation ranged from 0.27 to 0.83. The item homogeneity value was 0.43. Test-retest and inter-rater reliability for the total score was satisfactory (ICC: 0.96 and 0.95, respectively). The SIB-s showed moderate correlation with functional dependency scales (Barthel Index: 0.48, FAST: -0.74). Standard error of measurement was 3.07 for the total score. The SIB-s is a reliable and valid instrument for evaluating patients with severe dementia in the Spanish population of relatively brief instruments.