Clinical and experimental investigations of spontaneous impedance changes of the middle ear

The major symptoms of glomus tympanicum tumors are pulsatile tinnitus and spontaneous impedance changes (SICs) of the middle ear. On the other hand, SICs often occur even in the absence of pathological findings. The aim of this study was to analyze the occurrence of SICs in patients and healthy volunteers. We retrospectively evaluated 184 patients with SICs and/or complaints of periodic tinnitus. Most of them (n = 134) showed pulse-synchronous SICs. Pathological findings were recorded in only 66 patients. Binaural SICs were registered significantly (p = .03) more frequently in patients with arterial hypertension (63% versus 18%). Because of the positive correlation between arterial hypertension and the occurrence of SICs, the influence of increasing blood pressure (systolic blood pressure > 160 mm Hg after physical activity) on the occurrence of SICs was investigated in a prospective trial in healthy test subjects (n = 42). In 17 of them, pulse-synchronous SICs occurred for the first time or were registered at a lower sensitivity level after an increase in blood pressure. In summary, only half of the patients with pulse-synchronous SICs showed pathological findings. A significant correlation between high blood pressure and binaural pulse-synchronous SICs was demonstrated in patients with arterial hypertension and healthy volunteers after physical activity.