Recent studies using Wide Range Achievement Test — Revised (WRAT-R) Reading scores as estimates of premorbid abilities have demonstrated that distinct neuropsychological deficit profiles may be associated with specific cognitive disorders such as traumatic brain injury [Brain Inj. 9 (1995) 377] and lupus [Appl. Neuropsychol. 7 (2000) 96], and that these deficit scores predict both functional and financial outcomes [J. Head Trauma Rehab. 14 (1999) 220]. Although the main cognitive deficits associated with senile dementia of the Alzheimer's type (SDAT) are well known, the relative degree of impairment in each has yet to be adequately determined. The present study calculated indices of relative decline (zDiff) for 32 patients with probable SDAT by comparing estimates of premorbid functioning to concurrent neuropsychological test scores. The results suggest that intelligence is least declined in SDAT [Wechsler Adult Intelligence Scale — Revised (WAIS-R) FIQ, zDiff=−0.72], followed by attention [Wechsler Memory Scale — Revised (WMS-R) Attention Index, zDiff=−1.14], memory (WMS-R General Memory, zDiff=−2.12; WMS-R Delay Memory, zDiff=−2.33), speed of processing (Trails A, zDiff=−2.85), and cognitive flexibility (Trails B, zDiff=−5.33). Clinical and research implications are discussed.