[A measurement system for assessing binaural masking level difference (BMLD) in children].
BACKGROUND
The binaural masking level difference (BMLD) is defined as the contrast between homophasic and antiphasic signal conditions, and can be regarded as a measure for noise suppression by the auditory system.


METHODS
An adaptive two interval forced choice (IFC) measurement method was designed to assess BMLDs in children. The target tone was a 500 Hz sine pip which was masked with narrow band noise. The presentation of homo- and antiphasic signals was staggered in order to take into account artefacts--such as changes in vigilance--in a similar manner for both conditions.


RESULTS
Measurement was feasible in 57 out of 85 children (6-14 y.) with suspected auditory processing disorders. Mean BMLD was 7.4(+/-4.5 SD) dB. Five children revealed a BMLD close to 0 dB suggesting that they had no advantage in signal detection for the antiphasic condition. Eleven children were not able to cope with the task of measurement. In another 17 children, the measurements did not converge to a stable threshold.


CONCLUSIONS
The proposed measurement method was feasible with most of the children. With slight modifications of the threshold convergence, this proportion can be further increased. Whether or not the large inter-individual scatter of the results is an expression of the heterogeneous clinical clientele can only be determined when normative data are available.
Meister
H
H
Klinik und Poliklinik für Hals-, Nasen-, Ohrenheilkunde, Kopf- und Halschirurgie, Universität zu Köln. hartmut.meister@uni-koeln.de
Klüser
H
H
v Wedel
H
H
Walger
M
M
D000161:Acoustic Stimulation / Q000379:methods*; D000293:Adolescent; D001308:Auditory Perceptual Disorders / Q000145:classification / Q000175:diagnosis*; D001309:Auditory Threshold; D002648:Child; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004007:Dichotic Listening Tests / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D010470:Perceptual Masking; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014584:User-Computer Interface