科研之友
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摘要
Background: Transcutaneous electrical nerve stimulation (TENS) is a modality commonly used in pain management. %26lt;br%26gt;Objectives: This study investigated the hypoalgesic effects of alternating-frequency TENS (4 Hz for 3 s/110 Hz for 3 s) on pressure pain threshold (PPT). %26lt;br%26gt;Methods: Two-hundred and eight healthy, pain-free volunteers (19 to 59 y old; 104 males, 104 females) were randomized to 8 groups: 6 active TENS groups, placebo, and control (n = 26 per group). Parameter combinations were such that alternating-frequency TENS was combined with different levels of intensity %26quot;low%26quot; (strong but comfortable) or %26quot;high%26quot; (strong and uncomfortable but not painful). TENS was administered either at the forearm (segmental stimulation), at the ipsilateral leg (extrasegmental stimulation), or at both sites (dual-site stimulation) for 30 minutes and monitored for 30 further minutes. PPT measurements were taken bilaterally from the mid-point of first dorsal interosseous muscle, by an independent blinded rater, at baseline and at 6 subsequent 10-minute intervals. Square-root transformed data were analyzed using repeated measures analysis of covariance (baseline values and sex as covariates). %26lt;br%26gt;Results: Alternating-frequency TENS groups did not achieve significant hypoalgesic effects compared with placebo or control (P %26gt; 0.05). The largest increase in PPT (from baseline) was 76.6 kPa with low-intensity segmental alternating frequency TENS at the 20-minute stimulation time point. This change from baseline is below a difference of 100 kPa that is considered to be a clinically meaningful change in hypoalgesia. %26lt;br%26gt;Discussion: The alternating-frequency setting does not result in large hypoalgesic effects such as those previously reported using fixed-frequency TENS.
- 出版日期2013-6
