Impedance audiometry in infants with a cleft palate: the standard 226-Hz probe tone has no predictive value for the middle ear condition.

OBJECTIVE

Infants with a cleft palate and microscopical evidence for middle ear effusion attracted our attention because of normal tympanometry results and negative otoacoustic emissions. These contradictory findings initiated us to study to what extent high frequency tampynometry is able to supply us with more reliable results.

METHODS

Eighty-three ears of 46 cleft palate babies aged between 2 and 7 months were examined within the pedaudiological screening procedure via tympanometry before their surgical cleft closure. We applied probe tone frequencies of 226 Hz and 678 Hz. A control cohort of 69 ears of 36 babies without cleft palate was established. Results were later compared to the intraoperative findings.

RESULTS

By tympanometry with a 226-Hz probe tone, the examiners predicted the intraoperative findings correctly in only 29 cases of 83 examined ears (34.9%). However, their interpretation of tympanometry results by means of a 678-Hz probe tone correlated to the intraoperative findings in 96.3% cases.

CONCLUSIONS

In cleft palate babies tympanometry with a 678-Hz probe tone yields clear evidence of middle ear effusion and should therefore serve as an essential instrument before the first surgical step of palate closure. In case of applying the 226-Hz probe tone, we were often confronted with normal function of the Eustachian tube despite of proved existence of middle ear effusion.