title: Laser and somatosensory evoked potentials in amyotrophic lateral sclerosis.
abstract: Mild involvement of sensory nerves has been reported in previous studies in ALS patients. In this study, we assessed sensory pathways in ALS patients using laser evoked potentials (LEPs) and somatosensory evoked potentials (SSEPs).
  
  
  
  We recruited 18 ALS patients and 31 healthy subjects. Neodymium-doped yttrium aluminium perovskite (Nd:YAP)-laser was used to evoke LEPs in upper (UE) and lower (LE) extremities. N1 and N2P2 potentials were obtained from contralateral insular cortex (T3 or T4) and vertex (Cz), respectively. Median SSEPs were recorded from C3' or C4' and tibial SSEPs from Cz'.
  
  
  
  Compared to controls, ALS patients had longer N2 and P2 latencies, and smaller N2P2 amplitudes in both UE- and LE-LEPs (p<0.05), and longer latencies for median and tibial SSEPs (p<0.05). LEPs and SSEPs were abnormal in 72.2% and 56.6% patients, respectively.
  
  
  
  Cortical potentials showed that A-beta or A-delta sensory fibres, or both, were impaired in more than half of the ALS patients.
  
  
  
  The findings support that ALS is a multi-systemic disorder involving, although to a lesser degree, other systems than the motor.
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Baris
authors: B
authors: Isak
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark. Electronic address: hatitank@rm.dk.
authors: Hatice
authors: H
authors: Tankisi
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Birger
authors: B
authors: Johnsen
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Kirsten
authors: K
authors: Pugdahl
authors: Danish Pain Research Centre, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark.
authors: Nanna Brix
authors: NB
authors: Finnerup
authors: Department of Clinical Neurophysiology, Aarhus University Hospital, Aarhus, Denmark.
authors: Anders
authors: A
authors: Fuglsang-Frederiksen
mesh_terms: D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000503:physiopathology*; D016022:Case-Control Studies; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006801:Humans; D066331:Laser-Evoked Potentials; D008297:Male; D008875:Middle Aged; D011930:Reaction Time
keywords: ALS; Laser evoked potentials (LEPs); Sensory nerve system; Somatosensory evoked potentials (SSEPs)