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Rater Agreement on Gait Assessment during Neurologic Examination of Horses

Background Reproducible 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. Objectives To determine the reproducibility and validity of the gait assessment component in the neurologic examination of horses. Animals Twenty‐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). Methods Utilizing 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). Results The 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 Importance Clinicians should be aware of poor agreement even between skilled observers of equine gait abnormalities, especially when the clinical signs are subtle.

Standing CT and clinical progression of equine cholesterol granulomata.

CHOLESTEROL granulomata – benign choroid plexus masses often detected at equine postmortem examinations – are sometimes associated with central neurological signs (Ivoghli and others 1977, Johnson and others 1993, Jackson and others 1994, King 1997). Antemortem diagnosis was impossible until advent of magnetic resonance imaging (Maulet and others 2008) and CT (Vink-Nooteboom and others 1998, Vanschandevijl and others 2008). These two cases are the first to illustrate diagnosis using standing (unanaesthetised) CT (CT Lightspeed QX/i; GE medical systems) and describe the long-term follow-up of one case, revealing that the prognosis for some cases is fair. Case 1: A 12-year-old Irish Draught cross gelding was presented with a 10-day history of intermittent lethargy and abnormal head carriage. On presentation, episodes of generalised muscle rigidity and ataxia were noticed by the owner; the horse was obtunded with reduced tongue tone and drooping of the lower lip and reluctant to flex or extend the neck and back. Neurological signs had improved following administration of methylprednisolone, penicillin and flunixin meglumine. On presentation to the Royal Veterinary College, the horse was obtunded; menace responses were reduced bilaterally, but pupillary light reflexes were intact. Mild superficial gluteal muscle fasciculations were evident. The horse had an exaggerated guarding response to deep palpation of the neck at C5 to C7. The neuroanatomical localisation suggested forebrain involvement, but based on cervical discomfort on …

Evaluation of a technique for measurement of flow-mediated vasodilation in healthy ponies

OBJECTIVE To determine between-pony and within-pony variations and interobserver and intraobserver agreements of a technique for measurement of flow-mediated vasodilation (FMD) in healthy ponies. ANIMALS 6 healthy pony mares (weight range, 236 to 406 kg; body condition score range, 3/9 to 7/9; age range, 14 to 25 years). PROCEDURES In each pony, the left median artery was occluded with a blood pressure cuff (inflated to > 300 mm Hg for 5 minutes). Two-dimensional ultrasonographic images of the artery were recorded for 30 seconds before cuff inflation and for 2 minutes after cuff deflation. Maximum luminal diameters of arteries were compared with their baseline diameters to calculate FMD (relative percentage increase in luminal size). Images were obtained from 6 ponies 1 time and from 1 pony 6 times. Independent analysis of images was performed by 2 investigators, 1 of whom analyzed images on 2 occasions. RESULTS Mean ± SD FMD in 6 ponies (1 time) was 12.57 ± 4.28% and in 1 pony (6 times) was 7.30 ± 2.11%. Between-pony and within-pony coefficients of variation were 34.09% and 28.84%, respectively. Interobserver agreement was fair (intraclass correlation coefficient, 0.47); intraobserver agreement was poor (intraclass correlation coefficient, 0.30). CONCLUSIONS AND CLINICAL RELEVANCE FMD was identified and measured in ponies. Measurement of FMD is used to assess endothelial function in humans and has been investigated in dogs. Measurement of FMD in ponies appeared to be feasible and could be used to assess endothelial function (to determine predisposition for development of laminitis or cardiovascular diseases).

Cell specific microvesicles vary with season and disease predisposition in healthy and previously laminitic ponies

Microvesicles are small (up to 1 μm) vesicles found in plasma and other bodily fluids. They are recognised as part of the normal system of inter-cellular communication but altered numbers are also used as biomarkers of disease. Microvesicles have not been studied in detail in the horse but may be relevant to diseases such as laminitis. Identification of equine cell specific microvesicles was performed by developing a panel of cross reactive antibodies to use in flow cytometry to detect microvesicles of platelet, leucocyte and endothelial origin in plasma from healthy ponies and those predisposed to laminitis. The total number and proportion of microvesicles from the different cell types varied with season and there were more annexin V positive endothelial MV in non laminitic ponies compared to previously laminitic ponies. Development of this antibody panel and the technique for measuring microvesicles in the horse opens a new field for further investigation of these important structures in equine health and disease.