Laser evoked potential: Analysis of the methodology in post herpetic neuralgia

Alessandro Caminiti, Amelia Zaccaro, Andrea Truini, William Raffaeli, Domenico De Grandis

Department of Neurological Science, La sapienza University, Rome, Italy.
Department of Palliative Care and Pain Therapy, Infermi Hospital, Rimini, Italy.
Italian Clinical Neurophysiology Society, Rome, Italy.
Registered Nurse Department of Palliative Care and Pain Therapy, lnfermi Hospital, Rimini, Italy.

DOI: 10.4236/wjns.2012.21001                

Abstract

Background: selective activation and the contempo- rary recording of A delta and C fibers from Yap laser on the scalp is a new neurophysiological assessment, allowing the selective activation of the nociceptive system. Objectives: to evaluate if the damage of the nociceptive system was related to post herptic nevral-gia (PHN) development in a sample of 26 patients affected by Herpes zooster (HZ); secondly to assess if the impairment of thermal pathway and PHN development were related. Methods: Thirty-two patients were selected for the study, 26 of these were included in the study, whereas 6 were excluded because of cog- nitive impairment. All 26 study patients were sub- mitted to LEP analysis at baseline (T0) and after six months (T1), and the correlation between clinical thermal disease and the development of PHN was monitored. Results: pain duration was evidenced by the presence or absence of an instrumental signal in patients with acute HZ infection. There was total concordance between the absence of LEP signal and pain duration. The concordance between the clinical thermal disease and the pain duration was statisti- cally significant for 43% of the sample. Conclusions: our results suggested a possible role of LEP for PHN prognosis estimation; indeed, most patients affected by acute HZ, with absence of instrumental LEP signal had pain > 6 months. We also noted a significant (43% of cases) clinical concordance between the thermal pathway damage, the absence of instrumental signal and PHN development. Further studies are needed to address this issue.

Keywords

LEP; A Delta Fibers; C-Fibers; PHN Development; Pain; Spino-Thalamic Pathway

Conflicts of Interest

The authors declare no conflicts of interest.

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