PUPIL-DILATION RESPONSE TO TROPICAMIDE - A BIOLOGICAL TEST FOR ALZHEIMERS-DISEASE

The pupil dilation response to tropicamide has been proposed as a simp le test for demonstrating the central cholinergic deficit present in A lzheimer's disease (AD). We examined this response in 20 patients with clinically diagnosed mild probable AD and in 20 unrelated, cognitivel y intact, age-matched controls. A marked increase in pupil diameter wa s observed within 30 minutes in both groups. Differences between the g roups did not attain statistical significance. The ability of the prop osed test to discriminate between AD patients and healthy controls may be influenced by experimental procedures and by the ethnic background of the subjects under study. At present the pupil dilation response t o tropicamide cannot be considered a useful diagnostic aid.