Response characteristics of objective perimetry in persons living with epilepsy

Abstract

PurposeTo investigate safety and visual-field changes in people with epilepsy undergoing multifocal Pupillographic Objective Perimetry (mfPOP). Methods15 people with epilepsy and 15 controls underwent mfPOP in the context of routine clinical EEG testing. Safety measures comprised the proportion of participants developing an aura or seizure, a photoparoxysmal response, or increased epileptiform activity on their EEG during mfPOP. Pupil responses were obtained concurrently from 44 regions/field of each eye. Changes in standardised amplitude of constriction and time-to-peak were compared between people with generalised and focal epilepsy, and controls. ResultsNo participant developed an epileptic aura or clinical seizure during (or after) testing. One participant demonstrated EEG evidence of a focal subclinical seizure which began before mfPOP testing and continued unchanged during testing. Regional field sensitivities were increased in people with generalised epilepsy (+3.80 ± 1.43 dB compared to controls) but were reduced in individuals taking antiepileptic medication (−4.04 ± 1.74 dB). An extra delay of 24.9 ± 10.2 ms was seen in the time-to-peak of the responses in people with focal epilepsy. Based on receiver-operating characteristic analyses, discrimination of people with epilepsy from controls was greatest when using the 4 to 10 most abnormal visual field regions of each eye (%AUC 77.3 ± 9.70). SignificanceIn the absence of any safety signal, mfPOP appears harmless in people with epilepsy. The observed abnormalities in per-region sensitives and delays suggest that mfPOP may provide significant new insights into the study of epilepsy.