By Tatiana Gojdyk, DVM
Photography: Courtesy Equitom Clinic
Recently, the Equitom Clinic acquired new equipment that will allow the clinicians to obtain more objective information while examining horses suffering from ataxia.
In fact, the realization of a neurologic exam on an ataxic horse is founded on a subjective evaluation of the horse’s gait, attitude, and an examination of the cranial nerves, as well as a static and dynamic neurologic examination. The goal is to collect replicable data and to objectivize as much as possible the eventual presence of abnormalities during the neurologic exam.
However, the neurologic exam is a subjective exam that depends significantly on clinician’s experience. Moreover, some cases show an overlap between neurologic and orthopedic symptoms and, as practitioners, we are always searching for a way to objectivize as much as possible our clinical exams in order to correctly diagnose abnormalities that can sometimes be very subtle.
What is the MMEP test?
MMEP stands for ‘magnetic motor-evoked potentials’, a test based on transcranial magnetic stimulation (TMS) and the recording of a motor evoked potential. This is a non-invasive and non-painful exam for the horse, that is only mildly sedated during this procedure.
The exam is based on the transmission of an electro-magnetic impulse via an adapted probe that is placed on the scalp of the horse. Via the probe, the magnetic impulse is transmitted and is able to create a current at cerebral level that causes an excitement of descending motor tracts.
The muscular answer in the muscles of the forearm (muscle extensor carpi radialis), the forelimbs and the tibia muscle (muscle tibialis cranialis), and the hindlimbs, can then be used to verify the integrity of the descending motor tract from the brain to the muscles.
The time between the stimulation and the muscular response is called ‘latency’, and this is the most important parameter that is measured during the test. Other parameters such as the amplitude and the reliability of the reproducibility of the results are also parameters that need to be considered... To read the complete article you need to be a subscriber
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