Electric pulse frequency and magnitude of perceived sensation during electrocutaneous forearm stimulation.

OBJECTIVES: To investigate the effect that electric pulse frequency has on the perceived magnitude of sensation and to quantify the relationship between electric pulse frequency and perceived magnitude of sensation during low-intensity electrocutaneous stimulation. DESIGN: A repeated-measures research design was applied to evaluate the effect of electric pulse frequency on the perceived magnitude of electrocutaneous stimulation. SETTING: Electrocutaneous agents laboratory. PARTICIPANTS: University students (N=26) with normal hearing and normal sensation were recruited for the study. INTERVENTIONS: Electrocutaneous stimulation was applied to the forearm at 10 electric pulse frequencies. MAIN OUTCOME MEASURES: A cross-modality matching procedure was used in which stimulation intensity was matched with the level of loudness. Pairwise comparisons with 2 degrees of freedom at a power of 80% was performed. Statistical significance was set at P equal to .05. RESULTS: Electric pulse frequency had a significant effect on the perceived magnitude of sensation, with the perceived sensation growing between 0 and 120Hz (F=36.02; P<.001). The relationship between the 2 variables was strong (r(2)=.99; P<.01). CONCLUSIONS: Increasing the electric pulse frequency of electrocutaneous stimulation increases the perceived magnitude of the resulting sensation. This has implications for the use of electrocutaneous stimulation for both analgesia and muscle stimulation.