Simultaneous application of electronystagmography (ENG) and photoelectronystagmography (PENG) in the case of thermal labyrinth examination.

At examination of normal persons, the ENG registration method was compared with that of PENG. Special examinations were executed with regard to the behaviour of the beat rates during the culmination phase of thermal labyrinth reactions by using each of both registering methods. By synchronous recording of PENG and ENG, it was possible to settle the discrepancy of the greater number of beats in ENG compared with those of PENG, while the examinations were executed at different times. The PENG-method does not exclude an optical fixation due to the necessary interior illumination, and this results in a retarding of the reaction and smaller beat rates. This fact should be considered when comparing the results of ENG and PENG.