title: Motor-evoked potential gain is a helpful test for the detection of corticospinal tract dysfunction in amyotrophic lateral sclerosis.
abstract: OBJECTIVE
  The detection of upper motor neuron (UMN) dysfunction is necessary for the diagnosis of amyotrophic lateral sclerosis (ALS). However, signs of UMN dysfunction may be difficult to establish. This study aimed to determine whether motor-evoked potential (MEP) gain (MEP area/background electromyographic activity) represents an efficient alternative to assess UMN dysfunction.
  
  
  METHODS
  MEP area, MEP/compound muscle action potential (CMAP) area ratio, and MEP gain were tested at different force levels in healthy control subjects and ALS patients. Receiver operating characteristic (ROC) curve analyses was used to determine the diagnostic utility of MEP gain and compare it to alternative techniques, namely, diffusion tensor imaging (DTI) and the triple stimulation technique (TST).
  
  
  RESULTS
  MEP gain revealed a significant difference between the patients and healthy control subjects in contrast to MEP area and MEP/CMAP area ratio. The diagnostic utility of MEP gain was comparable with that of TST and superior to that of DTI.
  
  
  CONCLUSIONS
  MEP gain can distinguish ALS patients from control subjects and may be helpful for the diagnosis of ALS.
  
  
  CONCLUSIONS
  MEP gain appears to be a useful adjunct test and noninvasive method for the assessment of corticospinal dysfunction.
authors.affiliation: Reference Center for Neuromuscular Disorders and ALS, CHU La Timone, 264 rue Saint Pierre, 13005 Marseille, France.
authors.forename: Y
authors.initials: Y
authors.lastname: Duclos
authors.affiliation: Reference Center for Neuromuscular Disorders and ALS, CHU La Timone, 264 rue Saint Pierre, 13005 Marseille, France.
authors.forename: A M
authors.initials: AM
authors.lastname: Grapperon
authors.affiliation: Clinical Investigation Center - Pharmacology and Therapeutic Evaluation Center, CHU La Timone, 264 rue Saint Pierre, 13005 Marseille, France.
authors.forename: E
authors.initials: E
authors.lastname: Jouve
authors.affiliation: Clinical Investigation Center - Pharmacology and Therapeutic Evaluation Center, CHU La Timone, 264 rue Saint Pierre, 13005 Marseille, France.
authors.forename: R
authors.initials: R
authors.lastname: Truillet
authors.affiliation: Department of Clinical Research and Innovation, Biostatistics and Methodology Unit, Institut Paoli-Calmettes, 232 Boulevard Sainte-Marguerite-BP 156, 13273 Marseille Cedex, France.
authors.forename: C
authors.initials: C
authors.lastname: Zemmour
authors.affiliation: Reference Center for Neuromuscular Disorders and ALS, CHU La Timone, 264 rue Saint Pierre, 13005 Marseille, France.
authors.forename: A
authors.initials: A
authors.lastname: Verschueren
authors.affiliation: Reference Center for Neuromuscular Disorders and ALS, CHU La Timone, 264 rue Saint Pierre, 13005 Marseille, France; Aix Marseille Univ, INSERM, GMGF, Marseille, France.
authors.forename: J
authors.initials: J
authors.lastname: Pouget
authors.affiliation: Reference Center for Neuromuscular Disorders and ALS, CHU La Timone, 264 rue Saint Pierre, 13005 Marseille, France; Aix Marseille Univ, INSERM, GMGF, Marseille, France. Electronic address: sattarian@ap-hm.fr.
authors.forename: S
authors.initials: S
authors.lastname: Attarian
mesh_terms: D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000000981:diagnostic imaging / Q000503:physiopathology; D056324:Diffusion Tensor Imaging / Q000379:methods; D004576:Electromyography / Q000295:instrumentation / Q000379:methods*; D019054:Evoked Potentials, Motor; D005260:Female; D006801:Humans; D008297:Male; D011712:Pyramidal Tracts / Q000503:physiopathology*
keywords: Amyotrophic lateral sclerosis; Corticospinal tract; Motor neuron diseases; Transcranial magnetic stimulation; Upper motor neuron