The effect of high- and low-frequency H-wave therapy upon skin blood perfusion: evidence of frequency-specific effects.
The current study was designed to assess the putative physiological effects of H-wave therapy (HWT, a mode of therapeutic electro-stimulation) on skin blood flow in humans and to determine the relevance of frequency to any such effects. Laser Doppler flowmetry was used to record changes in blood perfusion on the dominant forearm of healthy human volunteers (n=36), who were each assigned, under randomized double blind conditions, to one of three experimental groups: placebo or HWT at 2 or 60 Hz. HWT stimulation was applied for 20 min, during which time concomitant skin temperature was recorded using three surface skin thermistors. Statistical analysis of perfusion measurement and skin temperature changes pre-, during and for up to 18 min post-HWT stimulation showed a highly significant increase in skin blood flow in the 2 Hz group when compared to placebo and 60 Hz (P<or/ = 0.01). This was associated with a significant increase in skin temperature during the period of stimulation (P<or/ = 0.05). No such differences were observed in the 60 Hz group. These results provide evidence that low-frequency HWT may produce direct localized effects on cutaneous blood flow, a finding relevant for clinicians working in the field of tissue repair.
McDowell
B C
BC
Rehabilitation Sciences Research Group, School of Health Sciences, University of Ulster at Jordanstown, Newtownabbey, Co. Antrim, BT37 0QB, Northern Ireland, UK.
McElduff
C
C
Lowe
A S
AS
Walsh
D M
DM
Baxter
G D
GD
D000293:Adolescent; D000328:Adult; D004599:Electric Stimulation Therapy; D005260:Female; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008297:Male; D012039:Regional Blood Flow; D012867:Skin / Q000098:blood supply*; D012881:Skin Temperature