Owner Observed Sleep Disturbances in Cavalier King Charles Spaniels with and Without Clinical Signs Compatible with a Chiari-like Malformation.

Chiari-like malformation (CM) and syringomyelia (SM) are prevalent in Cavalier King Charles Spaniels (CKCS). We hypothesized that CKCS with clinical signs compatible with CM+/-SM exhibit sleep disturbances. Thirty-seven CKCS with and without clinical signs compatible with CM+/-SM were included. No magnetic resonance imaging was required for inclusion. A questionnaire-based study was conducted using two validated instruments: CHASE to assess CM+/-SM severity and SNoRE 3.0 to evaluate sleep disturbances. Dogs with CHASE scores ≥7 were classified as having clinical signs. Nineteen dogs with clinical signs (median: 5 years, range: 3-10 years) and 18 without clinical signs (mean: 4.1 years, SD: 2.6) were included, with median CHASE scores of 13 (range: 7-18) and 1 (range: 0-6), respectively. Dogs with clinical signs had higher median SNoRE scores (median: 10, range: 6-30) than dogs without clinical signs (median: 7, range: 6-15). Sleep quality (padj = 0.008) and sleep interruptions due to dreaming (padj = 0.003) were significantly different between groups, with clinically affected dogs showing higher scores and greater variability. CKCS with clinical signs compatible with CM+/-SM show evidence of sleep disturbances, warranting confirmation with polysomnography and consideration in therapeutic management.