[Analysis of air caloric testing results for patients suffering from tympanic membrane perforation with vertigo]

To analyze characteristic of air caloric testing for patients with tympanic membrane perforation and to assess the availability of this testing for the patients.

Forty-three cases of chronic otitis media with tympanic membrane perforation and vertigo were investigated, in which there were 37 cases with single ear perforation and 6 cases with bilateral perforation. The patients were performed by air caloric testing, to observe the characteristic of nystagmus,slow phase velocity (SPV) and unilateral weakness (UW).

Four types of nystagmus, including enhancing, "normal", weakening and inversion, were observed with bilateral caloric air stimulation in ears with tympanic membrane perforation. Nystagmus of perforated ear presented SPV increased exceeding normal range or non-perforated ear and UW > 15% (15 cases, 17 ears), which was called enhancing type; normal nystagmus SPV in bilateral ear and UW < 15% (7 cases) was called "normal" type; weakened nystagmus SPV in perforated ear to non-perforated ear and UW > 15% (9 cases) was called weakening type; normal nystagmus in non-perforated ear and inverted caloric nystagmus in perforated ear (12 cases, 14 ears) was called inversion type. In patients with chronic otitis media recurring lately, inverted nystagmus was observed in perforated ears with effusion and humidity in the tympanic cavity, the other types were observed in patients in stillness stage of otitis media.

Bilateral caloric air became strong stimulation for the perforated ear, nystagmus of perforated ear with normal function of semicircular canal was stronger than that of the non-perforated ear. While the perforated ear with undermined function of semicircular canal, nystagmus could present normal or weakened. In the patients with otitis media in active stage, hot air stimulation could be turned to cool stimulation response so as to cause inverted nystagmus. Air caloric testing can be used to assess vestibular function of the patients with tympanic membrane perforation and vertigo.