Intra tester reliability of sympathetic skin responses in subjects with primary palmar hyperhidrosis.

BACKGROUND

Primary palmar hyperhidrosis (PPH) is a disorder related to sympathetic dysfunction. Iontophoresis can be used to reduce sweating rate. Sympathetic skin response (SSR) is commonly used to evaluate the sympathetic system. However, scarce evidence exists about the reliability of SSR parameters.

OBJECTIVE

To assess the relative and absolute reliability of SSR before and after the application of iontophoresis with aluminum chloride hexahydrate (ACH) gel or tap water in subjects with PPH.

METHODS

Twenty subjects were randomized to receive either iontophoresis with ACH gel or tap water. Three SSRs (amplitude and latency) with 5 s intervals from both hands in both groups were recorded before and after the application of iontophoresis for 30 min. Reliability of amplitude and latency of the SSR was assessed using intraclass correlation coefficient (ICC) with 95% confidence intervals, standard error of measurement (SEM), and minimal detectable change (MDC).

RESULTS

Amplitudes and latencies of SSR showed good to excellent test-retest reliability for ICC in both groups before iontophoresis. Except for right hand latency which was moderate (0.5-0.75). After iontophoresis, the ACH gel group still showed good to excellent agreement for SSR parameters, while the reliability of SSR parameters in the tap water group was reduced.

CONCLUSION

Subjects with PPH showed high intra-rater reliability for SSR parameters which was maintained after ACH gel iontophoresis and decreased after tap water iontophoresis. It seems that media used for iontophoresis or the state of media (gel vs liquid) may affect the reliability of SSR. Further research is recommended.