title: Tongue's motor evoked potentials in the diagnosis of primary lateral sclerosis (PLS): preliminary report.
abstract: BACKGROUND
  Primary Lateral Sclerosis (PLS) is an adult-onset neurodegenerative disorder due to a selective loss of precentral pyramidal neurons. Our purpose was to evaluate preferential impairment of pyramidal tract to bulbar muscles in patients with PLS and identify a valuable electrophysiological method to help clinicians in the differential diagnosis from Amyotrophic Lateral Sclerosis (ALS).
  
  
  METHODS
  We recorded Motor Evoked Potentials (MEPs) from tongue's and anterior tibialis muscles in six patients with PLS and compared the results, in terms of Central Motor Conduction Time (CMCT), amplitude of MEPs and duration of controlateral silent period (cSP), with those obtained both from ten age-matched healthy volunteers and ten patients affected by ALS.
  
  
  RESULTS
  For lower limbs, CMCT resulted significantly increased in PLS and ALS samples compared with healthy subjects (p<0.01); we did not disclose any difference between ALS and PLS groups (p=0.417). Instead for tongue's recordings, CMCT, absolute amplitude of MEPs and cSP were significantly altered in PLS patients towards both ALS patients and healthy volunteers.
  
  
  CONCLUSIONS
  We showed that tongue's MEPs are selectively impaired in PLS. This technique could be helpful to differentiate patients with PLS from those affected by upper motor neuron-predominant variants of ALS. Tongue's MEPs could represent an interesting electrodiagnostic test, potentially useful for the diagnosis of PLS.
authors.affiliation: Department of Neuroscience, Unit of Neurology, Pisa University Medical School, Pisa, Italy. tommaso.bocci@live.it
authors.forename: Tommaso
authors.initials: T
authors.lastname: Bocci
authors.forename: Lucia
authors.initials: L
authors.lastname: Briscese
authors.forename: Elisa
authors.initials: E
authors.lastname: Giorli
authors.forename: Chiara
authors.initials: C
authors.lastname: Pecori
authors.forename: Ferdinando
authors.initials: F
authors.lastname: Sartucci
mesh_terms: D000368:Aged; D004576:Electromyography / Q000379:methods; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016472:Motor Neuron Disease / Q000175:diagnosis* / Q000503:physiopathology*; D014059:Tongue / Q000503:physiopathology*; D050781:Transcranial Magnetic Stimulation / Q000379:methods