The Development of Frequency Weighting for Speech in Children with a History of Otitis Media with Effusion

Abstract

To determine the effect of chronic (recurrent) otitis media with effusion (OME) on frequency weighting in the perception of speech in noise. It was hypothesized that children with a history of OME weight speech information in the mid frequency region higher than control children. This is a matched cohort study looking at differences in frequency weighting in 12 children with a history of OME 1 to 2 wks after placement of tympanostomy tubes compared with 21 control children. Children were tested on their ability to identify key words in sentences presented in speech-shaped noise. The frequency content of the sentences was manipulated to determine the relative importance of frequencies in the regions of 1, 2, and 4 kHz. The frequency bands selected were 798 to 1212 Hz (low band), 1575 to 2425 Hz (mid band), and 3000 to 5000 Hz (high band). Initial testing involved adaptive runs where a speech-shaped masker was held at a constant level and the level of the speech with all three bands present varied. Once a level corresponding to 85% to 90% correct was identified, novel sentences were then presented at this signal-to-noise ratio in fixed block runs, with all bands present, or with one of the three bands omitted. The children in the OME group achieved 85% to 90% correct at a lower signal-to-noise ratio than controls in the adaptive testing, where all three speech bands were present. Fixed block testing indicated that children with OME history gave more weight to speech frequencies in the region of 2000 Hz compared with the age-matched control group. The results are consistent with an interpretation that the development of frequency weighting in the perception of speech can be affected by a history of OME.