Non-Invasive EEG Recordings in Epileptic Dogs (Canis familiaris)

Abstract

In addition to characteristic and easily identifiable behavioural signs-namely epileptic seizures-electroencephalography (EEG) has long been a standard component of epilepsy diagnosis protocols. In veterinary practice, EEG is typically performed in a semi-invasive manner, using subcutaneous electrodes and sedation. Here, we propose that the non-invasive polysomnography protocol, originally developed for basic research, can serve as a more welfare-friendly yet informative alternative for assessing epileptic brain activity in dogs. In this study, N = 11 family dogs diagnosed with epilepsy underwent a single non-invasive polysomnography session. EEG-based evidence for epileptic activity was detected in two cases. Polysomnography data from these 11 epileptic dogs were further analysed to evaluate sleep structure parameters. Compared to a matched control group of N = 11 clinically healthy dogs, the epileptic group exhibited reduced sleep efficiency, increased sleep latency, more wakings after sleep onset, and less time spent in drowsiness and non-REM sleep. These findings support the potential utility of non-invasive brain monitoring techniques, such as polysomnography, in the diagnosis and management of epilepsy in veterinary medicine.

Keywords: dog; epilepsy; non-invasive EEG; sleep.

Figure 1

EEG traces of Dog ID 2 (a) and Dog ID 3 (b) showing the epileptiform activity in a red circle, as per veterinary diagnostic criteria. The EEG derivations from top to bottom are Fz (fronto-central), F7 (right frontal), F8 (left frontal), Cz (central) and EOG (eye movements); the time interval between two dashed lines is 1 s.

Figure 2

Sleep macrostructure differences (mean ± SE values) between the epileptic patients (N = 11) and matched healthy control dogs (N = 11).