The impact of idiopathic epilepsy on sleep quality in dogs: A replication study and validation of the SNoRE questionnaire in Ukraine

Abstract

This replication study evaluated the specific characteristics of sleep quality in dogs diagnosed with idiopathic epilepsy compared to clinically healthy animals within the context of Ukrainian veterinary practice. The study is grounded in the hypothesis of a complex bidirectional relationship between epilepsy and sleep disorders, a phenomenon well-documented in human medicine but remaining insufficiently investigated in the veterinary field. The research was conducted between 2024 and 2025 at the "ANIMALIA" veterinary clinic in Dnipro, Ukraine. The study sample consisted of sixty-four dogs distributed into two equal groups using a case-control design: the main group (n=32) comprising dogs with a confirmed idiopathic epilepsy diagnosis matching the Tier II confidence level according to the International Veterinary Epilepsy Task Force guidelines, and a control group (n=32) of healthy dogs, strictly matched by age, sex, and breed characteristics. Data collection was performed using the owner-based validated Sleep and Nighttime Restlessness Evaluation questionnaire. The results revealed statistically significant differences in total sleep quality scores between the two groups. Dogs with idiopathic epilepsy demonstrated a significantly higher median total score of 12 with an interquartile range of 6–33, compared to a median score of 8 with an interquartile range of 6–22 in the control group (p<0.001), indicating substantial sleep impairment. Detailed factor analysis clarified that the decrease in sleep quality was driven exclusively by Factor 1 (Sleep Quality), which includes the ability to fall asleep and sleep continuity; the median score in the study group was 9 against 5 in the control group (p<0.001). Conversely, no significant differences were found for Factor 2 (Sleep Interruption due to Dreaming), with both groups showing a median score of 2 (p=0.99), suggesting the preservation of rapid eye movement sleep stability. Furthermore, the study investigated potential correlations with clinical variables. No statistically significant association was found between sleep quality scores and seizure frequency (p=0.73), the presence of cluster seizures (p=0.22), or the number and type of antiseizure medications administered (p=0.77). However, subjective owner reports indicated that 68.8% of dogs experience changes in sleep patterns during the postictal phase, with the majority (59.5 %) showing hypersomnia, likely reflecting a compensatory neural recovery mechanism. The findings confirm the clinical utility of the Sleep and Nighttime Restlessness Evaluation questionnaire as a sensitive screening tool for detecting non-motor comorbidities in canine epilepsy. The study highlights that sleep disturbances in dogs with idiopathic epilepsy should be regarded as an independent pathological feature rather than a direct consequence of pharmacotherapy. These results emphasize the necessity of integrating routine sleep assessment into standard management protocols for veterinary neurological patients to improve their overall quality of life.