Rater Agreement on Gait Assessment during Neurologic Examination of Horses

Abstract

BackgroundReproducible and accurate recognition of presence and severity of ataxia in horses with neurologic disease is important when establishing a diagnosis, assessing response to treatment, and making recommendations that might influence rider safety or a decision for euthanasia.ObjectivesTo determine the reproducibility and validity of the gait assessment component in the neurologic examination of horses.AnimalsTwenty‐five horses referred to the Royal Veterinary College Equine Referral Hospital for neurological assessment (n = 15), purchased (without a history of gait abnormalities) for an unrelated study (n = 5), or donated because of perceived ataxia (n = 5).MethodsUtilizing a prospective study design; a group of board‐certified medicine (n = 2) and surgery (n = 2) clinicians and residents (n = 2) assessed components of the equine neurologic examination (live and video recorded) and assigned individual and overall neurologic gait deficit grades (0–4). Inter‐rater agreement and assessment‐reassessment reliability were quantified using intraclass correlation coefficients (ICC).ResultsThe ICCs of the selected components of the neurologic examination ranged from 0 to 0.69. “Backing up” and “recognition of mistakes over obstacle” were the only components with an ICC > 0.6. Assessment‐reassessment agreement was poor to fair. The agreement on gait grading was good overall (ICC = 0.74), but poor for grades ≤ 1 (ICC = 0.08) and fair for ataxia grades ≥ 2 (ICC = 0.43). Clinicians with prior knowledge of a possible gait abnormality were more likely to assign a grade higher than the median grade.Conclusion and Clinical ImportanceClinicians should be aware of poor agreement even between skilled observers of equine gait abnormalities, especially when the clinical signs are subtle.

Comparison of visual lameness scores to gait asymmetry in racing Thoroughbreds during trot in‐hand

“…Compared with horses with neurological deficits (ICC value of 0.74 on a 0–4 scale for the neurological grade) (Olsen et al . ), we report similar values. We chose a variant of ICC focusing on assessing rank orders between observers (‘consistency’) (Hallgren ), rather than absolute agreement in lameness scores, limiting the influence of mean differences between observers, e.g.…”

Accuracy of transcranial magnetic stimulation and a Bayesian latent class model for diagnosis of spinal cord dysfunction in horses

“…Concerning the neurological examination, a limitation was that horses with grade 1 were also considered normal in the present study. This decision was based on the fact that certainly in mild cases, the interobserver agreement about the presence of neurological abnormalities might be poor . Therefore, caution is needed when taking decisions based on the clinical examination, especially when signs are subtle or when orthopedic disease is present.…”

“…This decision was based on the fact that certainly in mild cases, the interobserver agreement about the presence of neurological abnormalities might be poor . Therefore, caution is needed when taking decisions based on the clinical examination, especially when signs are subtle or when orthopedic disease is present. As the study population also included horses suspected of having orthopedic disease and a positive diagnosis of neurological disease might have a serious impact, the authors chose to give the horses with grade 1 ataxia the benefit of the doubt.…”

“…So, a presumptive diagnosis is often based on the history of the horse and the clinical neurological examination. However, certainly in subtle cases, the agreement between observers is poor and differentiation from orthopedic causes might be challenging …”

Science in brief: Highlights from the equine abstracts at the Eighth International Conference on Canine and Equine Locomotion

“…However, back movement is also influenced by factors such as back pain [3]. Despite the use of multiple visual clues, the diagnosis of low-grade lameness and ataxia remains highly variable between clinicians [4,5]. Differentiating primary forelimb lameness from a compensatory forelimb asymmetry caused by hindlimb lameness can be particularly challenging.…”