A diagnostic marker for speech delay associated with otitis media with effusion: backing of obstruents.

A companion paper in this issue reported diagnostic accuracy findings for a marker (the Intelligibility-Speech Gap) to identify speech delay associated with otitis media with effusion (SD-OME). The present paper reports findings for another possible diagnostic marker for SD-OME--Backing of Obstruents. Conversational speech samples and citation forms from 48 speech-delayed children with positive and negative histories for OME were analysed using both perceptual and acoustic methods. The perceptual findings indicated significant trends for backing to be more prevalent in children with positive compared to negative histories of OME. Among a number of candidate speech error variables, lowered first spectral moments on lingual stops and sibilant fricatives as obtained from moments analysis emerged as a promising acoustic correlate of backing. Positive and negative predictive values, and sensitivity and specificity values for the acoustic marker, were above 75% for each of three stimulus words targeting /k/, /z/ and /f/. Discussion considers alternative explanatory perspectives on the ontogenetic development of backing in children who have experienced the fluctuant hearing loss associated with early recurrent OME.