SAEVA Proceedings 2015 | Page 40

South African Equine Veterinary Association Congress 2015  Protea Hotel  Stellenbosch The Equine Neurological Examination Piercy RJ* MA VetMB MD PhD DipACVIM MRCVS Professor of Comparative Neuromuscular Disease Royal Veterinary College Summary In contrast to the neurological examination in smaller animals, the examination in horses is constrained by the size of the animal, and often, because we are attempting to detect more subtle defects in gait than might be apparent in small animals– defects that might have profound safety or welfare issue in horses. Although a comprehensive understanding of neuroanatomy is useful, it is not a prerequisite for a thorough examination – instead, the examiner should be aware of a few basic concepts and apply them in a methodical and logical manner during the examination. As always, past experience is useful, when identifying subtle deficits that might have a neurological origin. This presentation will cover the entire neurological examination with the aid of videos, revealing the characteristic signs that help observers detect abnormalities. Introduction The neurological examination is always performed with two main aims. The first is to help the clinician determine the likely presence or absence of neurological disease and the second, when neurological disease is suspected, is to localise the lesion or lesions. It is only then that additional tests can or should be performed in order to narrow down the differential diagnosis. In most cases, comprehensive neurological testing will be indicated by either (1) the history (for example an animal reported by the owner to have had a seizure-like episode); (2) the clinical examination (perhaps an unexplained area of muscle atrophy or sweating) or (3) as indicated by either negative, confusing or corroborating evidence from other tests (for example, a horse evaluated for pelvic limb lameness that may in fact have a neurological problem, or a horse with altered mentation or depression that has already been found to have abnormal hepatic function). Whatever the background, it is useful to get into the habit of performing a methodical examination, making sure that nothing is omitted. That way, experience of normal and abnormal is gained more rapidly and nothing is missed. Two different approaches to the examination can be taken: the first is based on individual systems with the different neurological modalities examined in turn (for example unconscious proprioceptive pathways); the second is an anatomic approach, where tests are performed in turn working from head to tail. A combination of the two is in my opinion more practical for examination of adult horses, but such a system requires the examiner to reflect on the various modalities that are being assessed during each part of the examination. Neuroanatomy For the purposes of the neurological examination, a comprehensive textbook understanding of neuroanatomy (though useful) is generally not required; instead, some rather basic tenets will in most cases suffice. Then, if necessary, more detailed analysis and neuroanatomic information can be derived from text books. The following points are in my opinion the basic facts that should be understood by anyone wanting to perform a decent neurological examination. White matter and grey matter  White matter is made up of myelinated axons of nerve cells. 40