HEARING DIAGNOSTICS IN CHILDREN USING DPOAE AND PURE-TONE THRESHOLDS

Janssen T (1),Bohnert A (2) ,Heller O (3) , Schirkonyer V (1), Oswald H (4), Zoth P (4), Keilmann A (2).

(1) Technische Universität München, Germany; (2) Universität Mainz, Germany; (3) Universität Würzburg, Germany; (4) Path medical GmbH, Germany.

The objective of hearing screening in childhood is to identify hearing impairment which is not obvious or apparent but will cause significant handicap for the child concerned. Late identification may compound problems in communication, language acquisition and affect other areas of development. Contrary to newborn hearing screening, for hearing screening in children more frequency-specific and quantitative information on the hearing loss is needed.

The purpose of the present study was to investigate the test-performance and the efficacy of a novel hand-held device (Path Medical GmbH, Germany) that offers test procedures on both a psycho-acoustical and a physiological base.

The psycho-acoustical test based on a 'multiple-choice auditory graphic interactive check' (MAGIC). Pure-tone thresholds were determined by selecting icons (animals) from a touch-screen that “produces” sounds with different frequencies and sound pressure levels. The test run was controlled by the child itself. After each test-sound, the child had to indicate if the sound was heard or not by touching the appropriate icon on the screen. From the “responses” (heard, not heard) the threshold was determined. There was a close correlation between the pure-tone behavioural threshold (gold standard) and the threshold obtained by the new method. By using appropriate images (animals) as visual amplifiers the child’s attentiveness was significantly enhanced.   

In the physiological test DPOAE I/O-functions were measured between 1.5 and 6 kHz. DPOAE-audiograms (derived from extrapolated DPOAE I/O-functions) were obtained in children aged between 0.5 to 15 years. The difference between DPOAE-audiogram thresholds and behavioural pure-tone thresholds decreased with increasing age from 40 to 5 dB proving the known discrepancy between behavioural und physiological measures in young children. Both tests are easy to handle and provide frequency-specific and quantitative information on both cochlear and central sound processing within a couple of minutes.

E-mail: T.Janssen@LRZ.TUM.de