title: Evidence of altered motor axon properties of the ulnar nerve in carpal tunnel syndrome.
abstract: OBJECTIVE
  To analyse recruitment properties of ulnar nerve motor axons in 60 CTS patients with negative ulnar nerve electrodiagnostic tests.
  
  
  METHODS
  Recruitment properties of the ulnar nerve were studied by analysing the relationship between the intensity of electrical stimulation and the size of motor response, i.e. the stimulus-response curve. Parameters of the curve (threshold, slope and plateau) were compared with those of the corresponding curve of the median nerve and both with parameters of 30 control curves.
  
  
  RESULTS
  The ulnar nerve stimulus-response curve was strikingly abnormal and, except for severity, closely resembled that of the median nerve. The slope of the curve was significantly less than that of controls and decreased with increasing abnormalities of the median nerve. This suggested that the pathological process involving the ulnar nerve was contingent with the severity of median nerve involvement.
  
  
  CONCLUSIONS
  We propose that the ulnar nerve may be subject to compression in Guyon's canal as a consequence of high pressure in the carpal tunnel of CTS patients.
  
  
  CONCLUSIONS
  Ectopic activity from ulnar axons may contribute to clinical spread of symptoms outside the median nerve territory in CTS. This does not exclude possible involvement of central plasticity mechanisms in producing extra-median symptoms in CTS patients.
authors.affiliation: Clinical Neurophysiology Unit, Department of Neurological and Behavioural Sciences, University of Siena, Policlinico Le Scotte, Viale Bracci 2, Siena, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Ginanneschi
authors.forename: F
authors.initials: F
authors.lastname: Dominici
authors.forename: P
authors.initials: P
authors.lastname: Milani
authors.forename: A
authors.initials: A
authors.lastname: Biasella
authors.forename: A
authors.initials: A
authors.lastname: Rossi
mesh_terms: D000328:Adult; D001369:Axons / Q000502:physiology*; D002349:Carpal Tunnel Syndrome / Q000503:physiopathology*; D004558:Electric Stimulation; D004576:Electromyography; D004594:Electrophysiology; D005260:Female; D006801:Humans; D008297:Male; D008475:Median Nerve / Q000503:physiopathology; D008875:Middle Aged; D009046:Motor Neurons / Q000502:physiology*; D011999:Recruitment, Neurophysiological / Q000502:physiology; D014459:Ulnar Nerve / Q000503:physiopathology*