(N26) Neurological Examination and Magnetic Resonance Imaging Findings in Dogs Diagnosed with Central Vestibular Disease

Abstract: Background - Neurological signs consistent with central vestibular disease include a head tilt with vertical nystagmus, proprioceptive deficits, altered mentation, cranial nerve dysfunction or cerebellar signs. There is little data regarding which of these signs are most predictive of central vestibular disease.
Hypothesis/Objectives – Evaluate the relationship between clinical signs associated with central vestibular disease and magnetic resonance imaging (MRI)-identified lesions.
Animals - One hundred and five hospital dogs diagnosed with central vestibular disease based on neurological examination with an MRI performed.
Methods – Retrospective evaluation. Dogs with a head tilt, and facial nerve dysfunction only, were excluded. Clinical signs, presence and location of lesions on MRI, and final diagnosis were recorded and evaluated. Prediction of MRI lesions were compared between dogs with one and multiple clinical examination abnormalities.
Results - Lesions on MRI were confirmed in 87 of the dogs (83%). Vertical nystagmus as the sole additional neurological finding was predictive of a lesion on MRI in 20% of dogs (n=15). All dogs with concurrent proprioceptive deficits (n=32) or cerebellar ataxia (n=2) only, had lesions on MRI. Dogs with only one clinical examination abnormality (n=55) were less likely to have a structural lesion on MRI compared to dogs with two or more abnormalities (n=50) (P=.003).
Conclusions and clinical importance - Vertical nystagmus as the sole addition clinical sign of central vestibular disease was the least predictive for identifying a lesion on MRI. More than one concurrent abnormality on examination is associated with higher likelihood of identifying lesions on MRI.