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Pupil reaction to light in Alzheimer's disease: evaluation of pupil size changes and mobility
Dimitris F Fotiou1, Catherine G Brozou, Anna-Bettina Haidich
1Laboratory of Clinical Neurophysiology, AHEPA Hospital, 54636 Thessaloniki, Greece. ffot@auth.gr
Aims:
The aim of the study is to assess pupil size changes and mobility evaluation as a diagnostic marker in patients with probable Alzheimer's disease (AD).
Material And Methods:
Twenty-three control subjects and 23 patients with probable AD entered the study. The latter patients had been under observation for 2 years and had undergone all necessary examinations to verify their initial diagnosis. A full record of the pupil's reaction to light was registered. Ten parameters from these data were measured, reported and then compared in both group of subjects.
Results:
Patients with probable AD had abnormal pupillary function compared with such function in healthy aging. All pupillary light reflex (PLR) variables differed significantly between the two groups (p<0.005) except baseline pupil diameter (D1) and minimum pupil diameter (D2). Maximum constriction acceleration (ACmax) was the best predictor in classifying a subject as normal or as AD with perfect classification ability (area under the curve =1, p<0.001). In addition, the correlation between the percentage recovery-redilatation (%D1) and ACmax was highly negative in the group of AD patients (r = -0.808, p<0.005).
Conclusions:
Pupil size changes and mobility examination may be a fast, non-invasive and efficient additional diagnostic marker in AD diagnosis.
