Vestibular schwannoma: negative growth and audiovestibular features

At the University Medical Center Utrecht, nonoperative management was used for 44 patients with a unilateral vestibular schwannoma between 1990 and 19 97. During that period, consecutive tumor sizes were determined by magnetic resonance imaging. Three of the 44 patients showed an average decrease in tumor size of 16.7% according to American Academy of Otolaryngology-Head an d Neck Surgery standards. This study describes the initial vestibular statu s and audiometric changes measured over up to 10 years in these three patie nts. Vestibular function was determined once, by means of the bithermal cal oric test, the torsion test, the saccade test, the smooth pursuit test, and the registration of spontaneous nystagmus. The three patients had severe v estibular paresis on the affected side. Pure-tone and speech audiometry wer e performed at regular intervals. Although the size of their tumors decreas ed, their hearing gradually deteriorated, just as it does in the majority o f patients with a growing or stable vestibular schwannoma. The observations presented here suggest that the development of symptoms in a vestibular sc hwannoma does not differentiate between patients with a stable, growing or shrinking tumor. The development of symptoms may be the result of the same pathogenetic mechanism.