Arterial pulse as a rare artifact observed on electronystagmography

We report a rare artifact observed during electronystagmography (ENG) in a 54-year-old woman. Rhythmic waves were seen on ENG even though no corresponding movements of the eyes or eyelids were detected, even by infrared camera monitoring. The rhythmic waves corresponded to the patient's pulse and occurred after the appearance of each QRS complex on electrocardiography (ECG). The waves were believed to have been generated by the pulse of the artery near the electrodes, which represented contamination of plethysmography at the temple. To the best of our knowledge, such an artifact has not been previously reported in the literature. When rhythmic waves unrelated to eye movements are recorded during ENG, an artifact of cardiovascular origin should be ruled out, and ECG and direct observation of the eyes are necessary.