title: Impedance changes elicited by electrocutaneous stimulation.
abstract: Electrical stimulation of the skin in the cavum conchae is followed by bilateral changes in the acoustic impedance of the ear due to reflex contraction of the stapedius muscle. A stimulator and a special surface electrode for electrical stimulation of the skin have been developed. The apparatus produces square-wave constant-current pulses independent of the electrical impedance of the electrode and the skin, and its hazard-proof. The effect of five independently variable stimulus parameters upon the elicited impedance changes has been examined in order to find a stimulus producing a large and reproducible impedance change without causing discomfort to the subject. Although a pronounced habituation phenomenon tends to mask the cause to effect relation of the various parameters, the results indicate that an appropriate stimulus is a pulse train of 0.5 s duration, consisting of individual pulses of a frequency of 200 Hz and 1 ms duration. The stimulus is applied at 10-second intervals.
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001299:Audiometry / Q000379:methods*; D004431:Ear, External / Q000502:physiology*; D004432:Ear, Middle / Q000502:physiology*; D004558:Electric Stimulation; D004566:Electrodes; D006801:Humans; D008875:Middle Aged; D009119:Muscle Contraction; D012018:Reflex; D012879:Skin Physiological Phenomena