title: Do A-waves help predict intravenous immunoglobulin response in multifocal motor neuropathy without block?
abstract: BACKGROUND
  Are there electrophysiological findings that predict response to intravenous immunoglobulin (IVIg) in patients with lower motor neuron (LMN) syndromes without multifocal conduction block (MCB)?
  
  
  METHODS
  We enrolled 9 patients with LMN syndromes without MCB to receive 18 weeks of IVIg therapy. Response was measured at weeks 2 and 18 using the Appel Amyotrophic Lateral Sclerosis (AALS) score (includes grip and pincer strength measures), ALS Functional Rating Scale (ALSFRS), and electrophysiological measures, including motor unit estimates (MUNEs).
  
  
  RESULTS
  No change occurred in AALS or ALSFRS scores posttreatment. Grip/pincer strength increased in 7 patients (P = 0.028) after initial treatment (responders); 2 showed no improvement (non-responders). No electrophysiological measure changed after treatment in either group but MUNEs trended higher (P = 0.055). "Abnormal A-waves" (complex, repetitive biphasic, or present in multiple nerves) occurred in pretreatment studies more often in responders (P = 0.028).
  
  
  CONCLUSIONS
  "Abnormal A-waves" may signal IVIg-responsive LMN syndromes even if conduction block is absent.
authors.affiliation: Department of Neurology, Division of Neuromuscular Disease, Mount Sinai School of Medicine, New York, New York, USA. langed@hss.edu
authors.forename: Dale J
authors.initials: DJ
authors.lastname: Lange
authors.forename: Rajwinder
authors.initials: R
authors.lastname: Nijjar
authors.forename: Andrei
authors.initials: A
authors.lastname: Voustianiouk
authors.forename: Gregory
authors.initials: G
authors.lastname: Seidel
authors.forename: Janki
authors.initials: J
authors.lastname: Panchal
authors.forename: Annabel K
authors.initials: AK
authors.lastname: Wang
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D016756:Immunoglobulins, Intravenous / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000187:drug effects* / Q000502:physiology; D009431:Neural Conduction / Q000187:drug effects* / Q000502:physiology; D010865:Pilot Projects; D011115:Polyneuropathies / Q000188:drug therapy* / Q000503:physiopathology*; D011237:Predictive Value of Tests; D016896:Treatment Outcome
chemical_list: D016756:Immunoglobulins, Intravenous