NEUROPSYCHOLOGICAL ASSESSMENT OF SEVERELY DEMENTED ELDERLY - THE SEVERE COGNITIVE IMPAIRMENT PROFILE

Background: Although the assessment of cognitive functioning in the la te stages of Alzheimer's Disease (AD) is important for identifying abi lities that may improve communication and interactions with severely i mpaired patients in clinical and institutional settings and for assess ing the efficacy of pharmacologic agents and behavioral interventions for the treatment of AD, few adequate instruments exist for measuring the cognitive capacities of these severely demented individuals. Objec tives: To evaluate the reliability and validity of the Severe Cognitiv e Impairment Profile (SCIP), a measure of neuropsychological functioni ng in severely demented patients, and compare it with Other available instruments. Design and Methods: We administered the Mattis Dementia R ating Scale (DRS), Mini-Mental State Examination (MMSE), SCIP, and Sev ere Impairment Battery (SIE) to 41 severely demented patients with AD participating in an AD research center. We used (1) Spearman rank corr elation coefficients to assess interrater and test-retest reliability and construct validity of the SCIP; (2) one-way analysis of variance w ith post hoc comparisons to examine performance on the SCIP and the SI E at different levels of dementia severity; and (3) descriptive statis tics to establish the sensitivity of the SCIP to cognitive functioning in a subgroup of very severely demented patients. Results: Interrater and test-retest reliability correlation coefficients were highly sign ificant for total SCIP score (r=0.99 and r=0.96, respectively) as well as for all SCIP subscales. High correlations were also found between SCIP scores and two widely used tests of global cognitive functioning, the DRS (r=0.91) and the MMSE (r=0.84), suggesting good construct val idity. The SCIP was able to significantly differentiate between four g roups of severely impaired patients divided by level of dementia sever ity, while the SIE was unable to differentiate between the less severe ly demented groups. A subgroup of 16 very severely demented patients ( DRS score, <50 points) obtained an average of 45% of total possible po ints on the SCIP, compared with an average of 1% and 21% of total poss ible points on the MMSE and DRS, respectively. After approximately 1 y ear of decline, 12 severely demented patients with AD were able to cor rectly answer an average of more than 58% of the items on the SCIP, co mpared with only 30% on the DRS and 20% on the MMSE. Conclusions: The SCIP is a reliable, valid measure of neuropsychological functioning in severely demented patients with AD with the ability to avoid both flo or and ceiling effects and to evaluate a wider range of cognitive abil ities than other tests used with severely impaired individuals.