Laser evoked potentials in carpal tunnel syndrome.
OBJECTIVE
The aim of this study was to evaluate the function of Adelta fibers at the hand level in patients with clinical symptoms of Carpal Tunnel Syndrome (CTS) using CO(2) laser evoked potentials (LEPs), in light of the intensity and distribution of sensory symptoms and pain.


METHODS
Thirty-four CTS outpatients (62 hands) were compared to 23 sex- and age-matched control subjects (46 hands). The periungueal skin of the first, second, third and fifth fingers, and the dorsum of the hands were stimulated in random order. The latency and amplitude of the N2, P2 and N1 components were evaluated with respect to the Nerve Conduction Study (NCS) data, clinical scales, pain intensity and glove-like symptoms distribution.


RESULTS
The amplitude of the N2-P2 complex was significantly reduced in CTS hands compared to normal hands after stimulation of the second and third fingers, even in patients with mild nerve conduction impairment. No significant fifth finger LEP abnormalities were found in patients with glove-like distribution symptoms. The N2-P2 amplitude at the second and third fingers was positively correlated with the severity of sensory symptoms.


CONCLUSIONS
The involvement of median nerve Adelta fibers in CTS seems to be an early phenomenon, which concurs with the impairment of large motor and sensory afferents and is linked to the severity of the disease.


CONCLUSIONS
The finding of reduced sensory symptoms in patients with severe thin afferents damage, may suggest a slight expression of central sensitisation phenomena in the advanced stage of CTS syndrome.
de Tommaso
Marina
M
Neurological and Psychiatric Sciences Department, Neurophysiopathology of Pain Unit, Bari University, Policlinico, Piazza G. Cesare 11, 70124 Bari, Italy. m.detommaso@neurol.uniba.it
Libro
Giuseppe
G
Difruscolo
Olimpia
O
Sardaro
Michele
M
Serpino
Claudia
C
Calabrese
Rita
R
Vecchio
Eleonora
E
Livrea
Paolo
P
D000328:Adult; D002349:Carpal Tunnel Syndrome / Q000503:physiopathology*; D016022:Case-Control Studies; D004558:Electric Stimulation / Q000379:methods; D005071:Evoked Potentials / Q000502:physiology*; D005260:Female; D006225:Hand / Q000294:innervation / Q000503:physiopathology; D006801:Humans; D007834:Lasers; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000502:physiology; D009431:Neural Conduction / Q000502:physiology; D010147:Pain Measurement / Q000379:methods; D011930:Reaction Time / Q000502:physiology; D012044:Regression Analysis; D055815:Young Adult