title: Re-evaluation of tropicamide in the pupillary response test for Alzheimer's disease.
abstract: In 1994, a pupillary response test using very dilute (0.01%) tropicamide, a cholinergic antagonist, evoked remarkable pupil dilation in subjects with Alzheimer's disease (AD) and has since been considered a diagnostic tool for AD. However, since this test was first reported, there have been studies suggesting it cannot provide a differential diagnosis of AD. Thus, the present study re-evaluated the pupillary dilation of AD (n=17) and non-AD (n=20) subjects at a 0.01% concentration of tropicamide and found that non-AD subjects, including young subjects, showed the same extent of pupil dilation as AD subjects. Furthermore, there was no significant difference between the average dilation rate of the two groups (P>0.05). When the tropicamide concentration was diluted to half of the initial concentration and performed for AD (n=14), vascular dementia (VD) (n=14), and young (n=16) subjects, the AD subjects showed a large dilation (mean pupil dilation rate: 133.8+/-15%) while the non-AD subjects did not show hypersensitivity to the new concentration of eye drops (105.4+/-9%). These differences in pupillary dilation between AD and non-AD patients were statistically significant (P<0.001). Based on these results, the most effective cutoff point of 0.005% tropicamide for differential diagnosis was 114.5% of the average pupil dilation rate for 60 min.
authors.affiliation: School of Fundamental Science and Technology (Biomedical Engineering), Graduate School of Science and Technology, Keio University, 3-14-1 Hiyoshi Kouhoku-ku, Yokohama, Kanagawa 223 8522, Japan. iijima@mnt.appi.keio.ac.jp
authors.forename: Atsuhiko
authors.initials: A
authors.lastname: Iijima
authors.forename: Munetaka
authors.initials: M
authors.lastname: Haida
authors.forename: Norio
authors.initials: N
authors.lastname: Ishikawa
authors.forename: Akinori
authors.initials: A
authors.lastname: Ueno
authors.forename: Haruyuki
authors.initials: H
authors.lastname: Minamitani
authors.forename: Yukito
authors.initials: Y
authors.lastname: Shinohara
mesh_terms: D000328:Adult; D000368:Aged; D000544:Alzheimer Disease / Q000175:diagnosis* / Q000503:physiopathology; D015140:Dementia, Vascular / Q000175:diagnosis* / Q000503:physiopathology; D003936:Diagnosis, Computer-Assisted; D003937:Diagnosis, Differential; D005189:False Positive Reactions; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D009184:Mydriatics; D011680:Pupil / Q000187:drug effects*; D015203:Reproducibility of Results; D014331:Tropicamide
chemical_list: D009184:Mydriatics; D014331:Tropicamide