Effect of fluidotherapy on superficial radial nerve conduction and skin temperature

Cross-sectional study.

The purpose of this study was to examine the effects of the superficial heating modality, Fluidotherapy, on skin temperature and on sensory nerve action potential (SNAP) conduction latency and amplitude of the superficial radial nerve in healthy individuals.

Fluidotherapy is a dry, superficial heating modality, which also provides tactile stimulation through the bombardment of air-fluidized cellulose particles. Previous literature has documented a direct relationship between skin temperature and neural conduction velocity; however, there is an absence of published research examining the effects of Fluidotherapy, and of tactile stimulation specifically, on neural conduction.

Twenty-one subjects between the ages of 22 and 31 years (mean+/-SD, 25.5+/-0.7 years) and without prior history of diabetes, alcoholism, renal or metabolic dysfunction, current pregnancy, or heat sensitivity were invited to participate. Subjects completed an upper quarter screening exam and medical history form prior to participation. One group underwent heat (46.7 degrees C-48.9 degrees C) and tactile stimulation, a second group underwent tactile stimulation alone, while a third served as controls. Dependent variables were assessed at 3 intervals: before the intervention, immediately after the intervention, and 20 minutes after the intervention. All interventions were 20 minutes in length.

A mixed 2-way analysis of variance indicated a significant interaction between time of neural conduction velocity assessment and treatment group for the dependent variables of sensory nerve action potential latency (P< .001) and skin temperature (P< .001). Appropriate post hoc tests were performed for simple effect comparisons. An inverse linear relationship existed between skin temperature and latency (r2 = .65; Pearson product coefficient, -.81).

Fluidotherapy treatment, which combines the effects of heat and tactile stimulation, significantly elevated superficial skin temperature, while tactile stimulation alone and no treatment (control group) did not bring about a temperature change. As the superficial skin temperature increased, there was a concomitant decrease in the distal sensory latency of the superficial radial sensory nerve action potential. These results should be an important consideration for the clinician using superficial heating modalities.