Equine laryngeal hemiplegia. Part III. A teased fibre study of peripheral nerves.
Abstract: Individual nerve fibres were isolated from the recurrent laryngeal and some distal hindlimb nerves, in an investigation of equine laryngeal hemiplegia. One hundred teased fibres were obtained from each of three sampling sites on both left and right recurrent laryngeal nerves, from 15 Thoroughbred horses. These fibres were graded descriptively and internode lengths measured. A distal distribution of pathology was demonstrated in all groups studied, but was most severe in the clinical group of horses. The predominant change was one of short thinly myelinated internodes interspersed amongst normally myelinated internodes, indicating remyelination of previously demyelinated areas of nerve fibre. Such pathological change was also reflected by the decreased mean internode length, and its increased variability associated with disease. However, it was determined statistically that these abnormal internodes were grouped along particular nerve fibres, rather than being randomly distributed between all nerve fibres. This is thought to indicate myelin sheath changes secondary to underlying axonal pathology. Thus it was concluded that the primary pathology was likely to be axonal in nature, while the high incidence of demyelination changes was a reflection of the chronic nature of the disease process. Thus, the distal distribution of pathology, the primary axonal involvement, the presence of changes in left and right recurrent laryngeal and distal limb nerves, all support the classification of equine laryngeal hemiplegia as a distal axonopathy.
Publication Date: 1986-11-01 PubMed ID: 16031232DOI: 10.1080/00480169.1986.35342Google Scholar: Lookup
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- Journal Article
Summary
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The research paper investigates the nerve fibre distribution in horses afflicted with equine laryngeal hemiplegia, concluding that this disease is a distal axonopathy, primarily associated with axonal pathology and chronic demyelination.
Investigative Approach
- The researchers procured individual nerve fibers from the laryngeal nerves and some distal hindlimb nerves of 15 Thoroughbred horses.
- A set of 100 teased fibers from sampling sites in both left and right recurrent laryngeal nerves were obtained and assessed.
- These fibers were examined descriptively and their internode lengths were measured.
Findings
- The study found evidence of distal pathology in all groups. This was most severe in the clinical group of horses.
- The main change identified was the presence of short, thinly myelinated internodes among normally myelinated internodes, suggesting remyelination of previously demyelinated areas.
- Mean internode length was lower and variability was increased in relation to disease progression.
- Statistical analysis revealed these abnormal internodes were grouped along particular nerve fibers instead of being randomly dispersed. This suggests myelin sheath changes due to underlying axonal pathology.
Conclusion
- Based on the findings, the primary pathology was considered to be axonal.
- The high incidence of demyelination changes was seen as indicative of chronicity of the disease.
- The predominant distal distribution of pathology, primary axonal involvement, and presence of changes in left and right recurrent laryngeal and distal limb nerves all support categorizing equine laryngeal hemiplegia as a distal axonopathy.
Cite This Article
APA
Cahill JI, Goulden BE.
(1986).
Equine laryngeal hemiplegia. Part III. A teased fibre study of peripheral nerves.
N Z Vet J, 34(11), 181-185.
https://doi.org/10.1080/00480169.1986.35342 Publication
Researcher Affiliations
- Department of Veterinary Clinical Sciences, Massey University, New Zealand.
Citations
This article has been cited 7 times.- Cercone M, Hokanson CM, Olsen E, Ducharme NG, Mitchell LM, Piercy RJ, Cheetham J. Asymmetric recurrent laryngeal nerve conduction velocities and dorsal cricoarytenoid muscle electromyographic characteristics in clinically normal horses. Sci Rep 2019 Feb 25;9(1):2713.
- Draper ACE, Piercy RJ. Pathological classification of equine recurrent laryngeal neuropathy. J Vet Intern Med 2018 Jul;32(4):1397-1409.
- Dupuis MC, Zhang Z, Druet T, Denoix JM, Charlier C, Lekeux P, Georges M. Results of a haplotype-based GWAS for recurrent laryngeal neuropathy in the horse. Mamm Genome 2011 Oct;22(9-10):613-20.
- Harrison GD, Duncan ID, Clayton MK. Determination of the early age of onset of equine recurrent laryngeal neuropathy. 1. Muscle pathology. Acta Neuropathol 1992;84(3):307-15.
- Al Shehab G, Naji R, Alali F, Alali A, Allowaim A, Almohammed A, Aljasim D, Alkhalifah A, Alhammad YMA, Marzok M, Mohamad ZA, Almuhanna AH. Laryngoscopic evaluation of arytenoid movements in pure Arabian horses. Open Vet J 2025 Jun;15(6):2875-2881.
- Hardwick JL, Ahern BJ, Crawford KL, Allen KJ, Anderson BH, Rose KJ, Franklin SH. Yearling laryngeal function grades II.2 and below are not associated with reduced performance. Equine Vet J 2025 Jul;57(4):953-966.
- Martin-Flores M, Sakai DM, Campoy L, Cheetham J. A model of transient laryngeal hemiplegia in dogs through conduction blockade of the recurrent laryngeal nerve. Am J Vet Res 2022 Jul 30;83(10).
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