Current knowledge of intermittent photic stimulation for electroencephalography in dogs.

Abstract

Intermittent photic stimulation is a standardized activation procedure for electroencephalography in humans that increases the detection of epileptic activity and improves diagnostic yield. However, its application in veterinary medicine remains inconsistent and methodologically heterogeneous. This narrative review synthesizes current knowledge regarding intermittent photic stimulation in dogs, critically evaluates variability in stimulus design, vigilance state, and electrode montage, and proposes a framework to support standardization in veterinary practice. Published veterinary studies demonstrate that photic stimulation can provoke generalized spike-wave and polyspike-wave discharges in selected epilepsy syndromes of dogs, particularly during awake recordings. However, protocols vary substantially in frequency range, light intensity, eye state control, flash duration, vigilance state, and lamp distance. Sedation and general anesthesia appear to attenuate retinal and thalamocortical responsiveness, decreasing the likelihood of eliciting photoparoxysmal responses. In addition, sparse and inconsistent electrode arrays limit spatial interpretation of photic responses and hinder cross-study comparisons. Drawing on established methodology used in humans and emerging veterinary data, this review outlines practical recommendations for standardized awake testing, defined stimulus parameters, and improved spatial sampling. Harmonized protocols may enhance diagnostic sensitivity, facilitate identification of photosensitive epilepsy syndromes in dogs, and strengthen translational alignment between epileptology in humans and animals. Standardization of intermittent photic stimulation represents an opportunity to improve the clinical utility and reproducibility of electroencephalography in dogs.