The clinical validity of the Mattis Dementia Rating Scale in staging Alzheimer's dementia.

Considerable heterogeneity exists in the criteria used for the establishment of stages of impairment for patients with dementia. The valid distinction of stages is important both for clinical interpretation and the study of dementia. This study reports on the use of the Mattis Dementia Rating Scale (DRS) in staging dementia. Using a sample of 42 patients diagnosed with Alzheimer-type dementia, DRS performance and a rating of Instrumental Activities of Daily Living (IADL) were compared with clinical ratings of dementia severity. Total DRS score provides a clinically valid measure of stage of impairment and appeared to provide a better distinction among stages than IADL score. However, use of the IADL score in conjunction with total DRS may improve correspondence with clinical staging over use of the total DRS score alone. Normative data for the DRS are also provided.