CAN TROPICAMIDE EYE DROP RESPONSE DIFFERENTIATE PATIENTS WITH PROGRESSIVE SUPRANUCLEAR PALSY AND ALZHEIMERS-DISEASE FROM HEALTHY CONTROL SUBJECTS

Pupillary dilation in response to dilute tropicamide eye drops has bee n proposed as a noninvasive diagnostic test to identify patients with Alzheimer's disease (AD). We examined 14 patients with progressive sup ranuclear palsy (PSP), another related neurodegenerative disorder char acterized by severe widespread cholinergic deficits and known central hypersensitivity to cholinergic blockade, to determine whether they al so showed a marked pupil dilation after administration of dilute tropi camide eye drops. Both PSP patients and healthy age-matched control su bjects had a similar pupillary response comparable with that previousl y reported in AD patients. Given its lack of specificity, physicians s hould be very cautious in using this test for identification of patien ts with AD.