The GBS profile was assessed for 39 patients with multi-infarct dementia (MID) and 34 patients with senile dementia of Alzheimer type (SDAT). The MID patients fulfilled the DSM-III criteria for multi-infarct dementia and had a score of 7 points or more on the Hachinski Ischemic Scale (HIS) and a score of 4 points or less on the Gustafson/Nilsson Alzheimer Scale (GNAS). The SDAT patients fulfilled DSM-III criteria for primary degenerative dementia and had a score of 5 points or more on the GNAS and a score of 6 points or less on the HIS. The total GBS score, the GBS subscale and relative subscale scores for intellectual functioning were significantly higher in patients with SDAT as compared with patients with MID. However, these subscale scores were considerably dispersed and nearly totally overlapping between patients with MID and SDAT, which implicates that the discriminative value is minimal. The validity between the GBS versus HIS and between the GBS versus GNAS was divergent, suggesting that the GBS scale has its own unique validity. In conclusion, the study does not support the hypothesis that the GBS profile may be of diagnostic value in clinical differentiation between multi-infarct dementia (MID) and senile dementia of Alzheimer type (SDAT).