Objective: To evaluate the feasibility of longitudinal assessment and the psychometric properties of both established and new outcome measures used in clinical trials of patients with dementia in a cohort of Spanish-speaking elders in the United States.
Methods: This is a prospectively collected multicenter study comparing patients with Alzheimer disease (AD) (N=77) and elderly controls (N=17) who are primary Spanish speakers. Spanish-speaking individuals with AD (SSI AD) were selected to represent predefined categories of impairment as determined by a Mini-Mental State Examination score. Controls were selected to approximately match by age and education (SSI C). Subjects were administered a series of Spanish translations of established outcome measures (Mini-Mental State Examination, Clinical Dementia Rating, Geriatric Dementia Scale), and Functional Assessment Staging (FAST)] and new outcome measures developed for United States in clinical trials to assess cognition, function, behavioral disturbance, and clinical global change. Half of the subjects were assessed at 1 and 2 months to evaluate reliability; all subjects were assessed at 6 and 12 months. Comparisons were made between patients and controls and between the Spanish-speaking cohort and a similar English-speaking cohort.
Results: The 12-month completion rate was 77%, with a trend toward greater impairment in those with full retention. Both established and new measures demonstrated good internal consistency and test-retest reliability in this cohort. All but one measure of cognition demonstrated excellent discriminability between AD subjects and controls. The SSI AD cohort declined significantly on measures of cognition, function, and clinical global change over the 12-month assessment period. The SSI AD and English AD (ESI AD) cohorts declined equivalently on the most common outcomes in clinical trials of AD (delayed recall, clinical global change). Likewise, the most common behavioral changes were also similar in the ESI and SSI groups. However, the annual change was lower in SSI AD than in the ESI AD on several other measures of cognition and function.
Conclusions: These results support the recruitment of Spanish-speaking patients and the use of Spanish language translations for use in the clinical trials for AD.