title: Multifocal neural conduction impairment in forestry workers exposed and not exposed to vibration.
abstract: OBJECTIVE
  The aim of the study was to assess peripheral neural involvement induced by exposure to hand-arm vibration.
  
  
  METHODS
  Twenty lumberjacks, working regularly with chain-saws and exposed to hand-arm vibration (group E) and 20 forestry workers performing heavy manual work and not exposed to vibration (group NE) were matched with a control group of 20 healthy non-manual workers (group C). The subjects of groups E and NE, all symptomatic, and of group C underwent extensive bilateral neurophysiological examination consisting of: sensory conduction (velocity and amplitude) of radial, median and ulnar nerves in digit-wrist segments; sensory conduction (velocity) of median nerve in wrist-elbow segment; mixed conduction (velocity and amplitude) of median and ulnar nerves in palm-wrist segments; motor conduction velocity, including distal motor latencies, and amplitude of median (elbow-wrist) and ulnar (elbow-wrist and across the elbow) nerves.
  
  
  RESULTS
  Electrophysiological abnormalities were found in 85% of group E's limbs, versus 62.5% of group NE's limbs. The most frequent pathological pattern in group E was a 'multifocal' impairment (multiple sites of several nerve segments), with a prevalent involvement of sensory rather than motor fibres in the hand, seldom extending to the forearm. Multivariate analysis showed that the neurographic parameters which better characterized workers exposed to hand-arm vibration had a pattern different from that usually found in idiopathic carpal tunnel syndrome (CTS).
  
  
  CONCLUSIONS
  These results suggest that vibration-induced neural involvement can be considered neither pure digital neuropathy, nor definite CTS, as previously described.
authors.affiliation: Istituto di Clinica delle Malattie Nervose e Mentali, Università di Siena, Policlinico le Scotte, Italy. gianninif@unisi.it
authors.forename: F
authors.initials: F
authors.lastname: Giannini
authors.forename: S
authors.initials: S
authors.lastname: Rossi
authors.forename: S
authors.initials: S
authors.lastname: Passero
authors.forename: M
authors.initials: M
authors.lastname: Bovenzi
authors.forename: G
authors.initials: G
authors.lastname: Cannavà
authors.forename: R
authors.initials: R
authors.lastname: Mancini
authors.forename: R
authors.initials: R
authors.lastname: Cioni
authors.forename: N
authors.initials: N
authors.lastname: Battistini
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000328:Adult; D000704:Analysis of Variance; D004576:Electromyography; D016468:Forestry; D006801:Humans; D008297:Male; D008875:Middle Aged; D009132:Muscles / Q000503:physiopathology; D009431:Neural Conduction / Q000502:physiology*; D016273:Occupational Exposure; D010523:Peripheral Nervous System Diseases / Q000209:etiology*; D014732:Vibration / Q000009:adverse effects*