A prospective multicentre study on sural nerve action potentials in ALS.
OBJECTIVE
To evaluate sensory nerve conduction studies in ALS in a prospective multicentre study involving 7 neurophysiologists from 6 European countries.


METHODS
Bilateral sural potentials were obtained in 35 ALS patients and 35 age-matched controls according to a standardised examination protocol using antidromic surface technique. The recordings from the right sural nerve of the controls were used for reference values. A reduction from the mean of controls greater than 2 SDs was considered abnormal.


RESULTS
Reduced sensory nerve action potential (SNAP) amplitude or reduced conduction velocity (CV), or both, was found in 6 ALS patients (17%). Decrease in CV was the most frequent finding, and was observed in 8 nerves from 5 patients. Reduced SNAP amplitude was found in 2 nerves from 2 patients. All changes were minor ranging from -2.1 to -3.2 SDs.


CONCLUSIONS
This is the first standardised multicentre study on sensory potentials in ALS. It confirms that although normal sensory findings should be expected in the majority of ALS patients, minor abnormalities are not uncommon.


CONCLUSIONS
Mild sensory abnormalities do not necessarily exclude a diagnosis of ALS.
Pugdahl
Kirsten
K
Department of Clinical Neurophysiology, Aarhus University Hospital, Nørrebrogade 44, Aarhus C, Denmark.
Fuglsang-Frederiksen
Anders
A
Johnsen
Birger
B
de Carvalho
Mamede
M
Fawcett
Peter R W
PR
Labarre-Vila
Annick
A
Liguori
Rocco
R
Nix
Wilfred A
WA
Schofield
Ian S
IS
D000200:Action Potentials / Q000502:physiology*; D000328:Adult; D000368:Aged; D000690:Amyotrophic Lateral Sclerosis / Q000175:diagnosis* / Q000503:physiopathology*; D004576:Electromyography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009431:Neural Conduction / Q000502:physiology*; D013497:Sural Nerve / Q000503:physiopathology*