BioPsychoSocial Assessment Tools for the Elderly - Assessment Summary Sheet
Test: Global Deterioration Scale (GDS)
Assessment Tool Category: Dementia/Alzheimer’s
Variations/Translations: Reisberg Scale
Setting: Long-term care institutions
Method of Delivery: Assessed by formal caregivers
Description: The GDS provides caregivers with an overview of the stages of functional decline for those suffering from a primary degenerative dementia such as Alzheimer’s disease. The GDS is comprised of 7 stages, each defined by a set of clinical characteristics. These characteristics are based on dimensions such as memory, learning, communication, sleep, and physical, mental, and social impairment.
Scoring/Interpretation: The higher the stage, the more severe the cognitive decline. Stage 1: No cognitive decline (normal function; Stages 2-3: Mild cognitive decline; Stage 4: Moderate cognitive decline; Stage 5: Moderate-severe cognitive decline; Stages 6-7: Severe cognitive decline.
Time to Administer: Variable, depending on time required for observation of patient.
Availability: Available online through the Alzheimer’s Society (see below), free of charge.
Validity (Quantitative): Concurrent validity was established by comparing scores of the GDS to scores from the MMSE (Mini-Mental State Exam) and showed high correlation between the two tools (results reported in Reisberg et al, 1994). Clinical/biological validity was also demonstrated to be satisfactory by comparing GDS results with results from psychometric tests (r = 0.30-0.60), CT scan measures (r = 0.50 for sulcal enlargement and 0.60 for ventricular dilation), and cerebral blood flow (r = 0.70-0.80) (Herndon, 2006).
Reliability (Quantitative): Interrater reliability for the GDS was found to be high, ranging from 0.87 to 0.97 in various studies (Herndon, 2006).
Eisdorfer, C., Cohen, D., Paveza, G., Ashford, J.W., Luchins, D.J., Gorelick, P.B., Hirschman, R.S., Freels, S.A., Levy, P.S., Semla, T.P., & Shaw, H.A. (1992). An Empirical Evaluation of the Global Deterioration Scale for Staging Alzheimer’s disease. The American Journal of Psychiatry, 149, 190-194.
Herndon, R.M. (2006). Handbook of Neurologic Rating Scales (2nd ed.). New York: Demos Medical Publishing.
Reisberg, B., Ferris, S.H., Leon, M.J., & Crook, T. (1982). The Global Deterioration Scale for assessment of primary degenerative dementia. American Journal of Psychiatry, 139, 1136-1139.