Investigation of possible cognitive, behavioral, and emotional heterogeneity in patients with Alzheimer's disease

This study sought to examine whether subtypes of patients with Alzheimer's Disease (AD) existed as measured by seven scales of the Cognitive Behavior Rating Scale (CBRS). Wards' method of cluster analysis was used to group 104 AD patients into subgroups. Three clusters were identified: (a) Moderately Impaired, (b) Severely Impaired, and (c) Emotionally Intact. These clusters displayed more differences in symptom severity than type of symptom. Clusters could be partially defined by the amount of time since diagnosis, while differences in the clusters' profile of scores had little or no descriptive utility. Results failed to support the existence of AD subtypes and yet did not follow the traditional "stage" descriptions of AD progression either. Findings are discussed within a modified "phase" description of AD progression.