Background : Post-herpetic neuralgia is the most serious one of herpes zoster complications and its incidence becomes higher as the age of the patient increases. Nevertheless, besides considering the age and onset time of treatment, there is no
more
objective factor estimating the prognosis of post-herpetic neuralgia.
Objective : The aim of this study is to understand the progression of herpes zoster and estimate the prognosis of post-herpetic neuralgia by practicing eletrodiagnostic tests to patients with herpes zoster.
Methods : We evaluated the pain scales in 26 patients with herpes zoster on the first visit and 2 months later. We also performed electrodiagnostic tests, more objective and reproducible methods, including somatosensory evoked potentials and
motor
nerve
conduction studies on both the involved and uninvolved sites of 32 lesions in 26 patients with herpes zoster, and then compared the results with the change of pain scales.
Results :
1. the pain category scale and visual analogue scale on the second examination were significantly decreased compared with those on the first examination (P<0.05).
2. Latencies of intercostal intercostal somatosensory evoked potentials recorded on scalp and spine were significantly delayed in involved sides compared with those in uninvolved sides(P>0.05).
3. In the latencies and conduction velocities of motor nerve conduction studies, no significant differences were seen between involved sides and uninvolved sides.
4. On the second examination, latency differences of somatosensory evoked potentials were significantly improved compared with those on the first examination (P<0.05).
5. Among the various somatosensory evoked potentials parameters, P1 latency difference of cortical somatosensory evoked potentials between involved and uninvolved sides correlated significantly with pain category scale and visual analogue scale
on
second examination (r=0.48, P<0.05; r=0.51, P<0.05, respectively). N1 latency difference of spinal somatosensory evoked potentials between involved and uninvdolved sides correlated significantly with a visual analoge scale on the first
examination
and
pain category scale on the second examination (r=0.61, P<0.05; r-0.78, P<0.05, respectively).
Conclusion : Intercostal somatosensory evoked potentials can be a useful and reliable technique to predict the development and severity of post-herpetic neuralgia.
(Kor J Dermatol 1995;33(6) : 1099~1107)
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