title: Effects of syringomyelia on electrodiagnostic test results in Cavalier King Charles Spaniels.
abstract: OBJECTIVE
  To determine the effects of syringomyelia on electromyography (EMG) findings, somatosensory-evoked potentials (SEPs), and transcranial magnetic motor-evoked potentials (TMMEPs) in Cavalier King Charles Spaniels (CKCSs).
  
  
  METHODS
  27 client-owned CKCSs that underwent prebreeding magnetic resonance imaging screening or investigation of clinical signs consistent with syringomyelia.
  
  
  METHODS
  In dogs with (n = 11) and without (16) magnetic resonance imaging-confirmed syringomyelia, the median nerve in each thoracic limb was stimulated and SEPs were recorded over the C1 vertebra; onset latency and latency and amplitude of the largest negative (N1) and positive (P1) peaks were measured. The TMMEPs were recorded bilaterally from the extensor carpi radialis and tibialis cranialis muscles; onset latencies in all 4 limbs were measured. Bilateral systematic needle EMG examination was performed on the cervical epaxial musculature, and the number of sites with spontaneous activity was recorded.
  
  
  RESULTS
  In dogs with syringomyelia, amplitudes of N1 and P1 and the amplitude difference between P1 and N1 were significantly smaller than those recorded for dogs without syringomyelia (approx 2-fold difference). No difference in SEP latencies, TMMEP latencies, or the proportion of dogs with > 2 sites of spontaneous activity detected during EMG examination was detected between groups.
  
  
  CONCLUSIONS
  Results indicated that SEP amplitude at the C1 vertebra was a more sensitive measure of spinal cord function in CKCSs with syringomyelia, compared with results of EMG or TMMEP assessment. Measurement of SEP amplitude may have use as an objective assessment of the evolution and treatment of this disease.
authors.affiliation: Department of Veterinary Medicine, The Queen's Veterinary School Hospital, University of Cambridge, Cambridge, CB3 0ES, England. tom.harcourtbrown@bristol.ac.uk
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Harcourt-Brown
authors.forename: Zoe
authors.initials: Z
authors.lastname: Belshaw
authors.forename: John E
authors.initials: JE
authors.lastname: Parker
authors.forename: Nick D
authors.initials: ND
authors.lastname: Jeffery
authors.forename: Nicolas
authors.initials: N
authors.lastname: Granger
mesh_terms: D000818:Animals; D002574:Cervical Vertebrae / Q000503:physiopathology; D004283:Dog Diseases / Q000175:diagnosis* / Q000503:physiopathology*; D004285:Dogs; D004576:Electromyography / Q000592:standards / Q000662:veterinary; D019054:Evoked Potentials, Motor; D005073:Evoked Potentials, Somatosensory; D005260:Female; D005552:Forelimb / Q000503:physiopathology; D008279:Magnetic Resonance Imaging / Q000662:veterinary; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D010375:Pedigree; D011446:Prospective Studies; D013116:Spinal Cord / Q000503:physiopathology*; D013595:Syringomyelia / Q000175:diagnosis / Q000503:physiopathology / Q000662:veterinary*; D050781:Transcranial Magnetic Stimulation / Q000592:standards / Q000662:veterinary