Inter‐rater agreement of the canine modified Ashworth scale for assessment of limb tone in dogs presenting with acute myelopathic signs

BACKGROUND: This study aimed to assess the inter-rater reliability of a canine adaptation of the modified Ashworth scale (CaMAS) for the assessment of muscle tone in dogs. METHODS: Dogs presented to the neurology service of a single referral centre between November 2023 and October 2024 underwent a muscle tone evaluation by two independent raters using the CaMAS. Inter-rater agreement was assessed using Kendall's tau coefficient of concordance (τ). RESULTS: One hundred dogs were included. The overall agreement was good (τ > 0.64), with τ values exceeding 0.75 in the pelvic limbs and 0.64 in the thoracic limbs. Agreement in dogs with cervical lesions was lower (τ = 0.42-0.62) than that with thoracolumbar lesions (τ = 0.69-0.81). Medium and large breeds demonstrated higher agreement (τ = 0.70-0.78 and 0.51-0.86, respectively) than small breeds (τ = 0.44-0.81). Inter-rater agreement for the first 50 cases ranged from τ = 0.41 to 0.79, and for the last 50 cases, it ranged from τ = 0.73 to 0.93. LIMITATIONS: Intra-rater agreement was not assessed. Being an adaptation of a human scale might limit the scale's application in dogs due to anatomical and biomechanical differences. Positioning of the dog during examination and behaviour may also influence assessment. CONCLUSIONS: Overall, the inter-rater agreement was good, supporting the scale's potential as an additional tool for muscle tone assessment in dogs. Familiarity with the scale could influence inter-rater reliability.