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Electrophysiological Studies in American Quarter Horses with Neuroaxonal Dystrophy

By Monica Aleman, Danika L. Bannasch, Carrie J. Finno, Steven R. Hollingsworth, John E. Madigan, Ron Ofri, and Laramie Winfield

Published in the Equine Veterinary Journal (Purchase access to read the complete article)


Objective: Neuroaxonal dystrophy (NAD) is a disease characterized by the sudden onset of neurologic signs in horses ranging from 4 to 36 months of age. Equine degenerative myeloencephalopathy (EDM), a disease that has been associated with low vitamin E concentrations, is considered a more advanced form of NAD. The objective of this report is to describe the electrophysiological features of NAD/EDM in American Quarter horses (QHs).

Horses: Six NAD/EDM-affected QHs and six unaffected QHs were evaluated by ophthalmic examination and electroretinography. Five of the NAD/EDM-affected QH and five unaffected QHs were also evaluated by electroencephalography (EEG).

Results: Ophthalmic examination, ERGs, and EEGs were unremarkable in NAD/EDM cases.

Conclusions: Neuroaxonal dystrophy/EDM does not appear to cause clinical signs of ocular disease or functional ERG/EEG deficits in QHs.


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