Enlargement of the vestibular aqueduct.

Enlarged vestibular aqueduct, a recently identified anomaly, is typified by an enlarged vestibule, dilation of the ampullated portions of the horizontal and superior semicircular canals, an abnormal cochlea, and hearing loss. In the case described a 16-year-old boy had congenital hearing loss, episodic vertigo, and abnormal vestibular function testing. Tomograms and CT scans confirmed the diagnosis of bilaterally enlarged vestibular aqueducts. The vertiginous episodes decreased in frequency and severity with a no-salt-added diet. The authors conclude that the enlarged vestibular aqueduct is associated not only with other structural inner ear abnormalities and hearing loss, but also with abnormal vestibular function.