Laser evoked potentials in carpal tunnel syndrome.
ABSTRACT 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.
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.
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.
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.
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.
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ABSTRACT: The aim of the study was to investigate the relationship between the presence of neuropathic pain assessed by the Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) scale and electrophysiological findings in patients with carpal tunnel syndrome (CTS). We studied 124 hands with idiopathic CTS with pain complaints involving hand and wrist. All hands were assessed by the LANSS with which a score of 12 or more is defined as pain dominated by neuropathic mechanisms. These hands were assigned to minimal, mild, moderate, severe, or extreme severe groups according to the results of the median nerve conduction studies. A LANSS score ≥ 12, suggestive of pain dominated by neuropathic mechanisms, was defined in 59 (47.6%) CTS hands. Pain intensity was significantly higher in CTS hands with a LANSS score ≥ 12 (P < 0.001). Among electrophysiological findings, compound muscle action potential amplitude was significantly lower in hands with a LANSS score ≥ 12 compared with hands with a LANSS score < 12 (P = 0.020). Severity of CTS was not significantly different between LANSS ≥ 12 and LANSS < 12 groups. Electrophysiological severity was significantly higher in CTS hands with evoked pain (P = 0.005) and allodynia (P < 0.001) in LANSS subscore analysis. We suggest that the presence of pain dominated by neuropathic mechanisms in CTS is not related to electrophysiological CTS severity. Neuropathic pain should be assessed carefully in patients with CTS, and an appropriate treatment plan should be chosen, taking into account the clinical and electrophysiological findings together with the true pain classification.Neuropsychiatric Disease and Treatment 01/2013; 9:65-71. · 2.15 Impact Factor
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ABSTRACT: Several papers were published since the first clinical applications of laser evoked potentials (LEPs) in disorders of the nociceptive system. While studies produced until five years ago were mostly addressed at identifying lesions of the nociceptive system, more recent papers used LEPs as an instrumental tool for the diagnosis of neuropathic pain. LEPs have also proved useful in demonstrating the pathophysiological mechanisms underlying different types of neuropathic pain (e.g., paroxystic and ongoing neuropathic pain). This is of utmost importance, as pain treatment should take physiopathological mechanisms, rather than etiology into account. Although there are still some limits for the routine use of LEPs as a diagnostic tool, this review of the literature demonstrates that LEP recording has become mandatory for the functional assessment of patients with hypoalgesia or neuropathic pain.Neurophysiologie Clinique/Clinical Neurophysiology 10/2012; 42(5):345-53. · 1.46 Impact Factor
- Pain 08/2010; 150(2):370–371. · 5.64 Impact Factor