1. Creating sound valuewww.hearingcrc.org Kelley Graydon 1,2,, Gary Rance 1,2, Dani Tomlin 1,2 Richard Dowell 1,2 & Bram Van Dun 1,4. 1 The HEARing Cooperative Research Centre, 2 The University of Melbourne Department of Audiology and Speech Sciences, 3 National Acoustic Laboratories 4 Conductive hearing loss compromises the quality of the auditory signal reaching the brain. To establish the impact of persistent conductive hearing loss in early childhood, speech perception in spatially separated background noise was measured in school-age children with documented middle-ear histories. Children with conductive hearing loss history showed significantly poorer binaural hearing than age-matched controls despite having normal hearing at the time of assessment. Furthermore, the degree of hearing impairment caused by the conductive hearing loss was a significant predictor of long-term speech perception ability. We would like to thank all the families that have participated in this study and the staff at Taralye for assisting with recruitment. Also thank you to Harvey Dillon from the National Acoustics Laboratory for his assistance. Conductive hearing loss as a result of otitis media can compromise the auditory signal reaching the central auditory nervous system. To accurately determine the extent to which this impacts on listening ability in the long-term requires documented evidence of middle-ear histories, which has previously been limited. This study aimed to establish whether not only a reported history, but the severity of the middle-ear pathology in early childhood leads to functional listening deficits at school-age. It is hypothesised that children that demonstrate a significant history of conductive hearing loss and middle-ear pathology will have long-term functional listening deficits. Abstract Can Middle Ear Disease in Early Childhood Impact on Listening Ability in the Longer Term? Seventy-six children aged 6-12 years participated in the study (mean= 9 years, 2 months); 40 children with documented history of conductive hearing loss and otitis media and 36 aged-matched controls. Middle-ear and conductive hearing loss histories were determined retrospectively from extensive clinical records, commencing in the first year of life and extending until at least four years of age. Inclusion criteria for the conductive history group: First hearing test <12 months of age. At least three documented episodes of bilateral otitis media (4FA >20dBHL). All children were demonstrated to have normal hearing acuity and middle-ear function at the time of assessment (no significant differences compared to age-matched controls). The Listening in Spatialized Noise-Sentences (LiSN-S) test was used as a measure of speech perception in noise. Specifically, it determines the ability to effectively utilise the binaural cues of interaural timing and intensity differences for spatial listening advantage. The LiSN-S assesses speech reception thresholds in four listening conditions that vary in terms of location of background noise and voice. Z-scores (that account for maturational effects) are generated from the test conditions. Evaluation was based on z-scores obtained in the same voice, zero degrees (SV0) and the different voice, ninety degrees (DV90) conditions. Advantage measures were also calculated (talker, spatial and total) where spatial advantage represents the improvement provided by spatial cues. Analysis involved comparisons between degree of binaural hearing impairment and extent of hearing impairment during the conductive episodes, as documented in clinical records. Results 1. LISN-S measures Children with a history of significant (three or more documented episodes) of conductive hearing loss performed poorer than the age- matched controls (p= <0.05) on all conditions that relied on binaural cues (DV90, spatial advantage and total advantage). There were no significant differences between the two groups on either the SV0 listening condition or the talker advantage measure (condition/measures that contain no binaural cues), supporting that group differences seen are due to binaural listening differences. Significant correlations were also found between the degree of conductive hearing impairment in the first four years of life and long- term speech perception ability, suggesting the degree at which hearing is impaired has an effect on long-term listening ability. Results support a link between early conductive hearing loss and binaural listening deficits that persist even once hearing has returned to normal. Furthermore, results suggest the greater the conductive hearing impairment early in life, the greater the speech perception deficit. These findings highlight the need for early intervention and screening measures of functional listening ability in children with a history of middle ear problems. Figure 1. z-score for controls and subjects on the four LISN-S conditions/measures. z-score Spatial processing disorder was identified in 20% of children with a conductive hearing loss history and 1% of the control children. To investigate the long-term effects of conductive hearing loss on listening ability in school- age children. A secondary objective was to establish if the severity of the conductive hearing loss in early life affects how children learn to utilise the auditory cues important for speech perception in noise. * Figure 1 shows the children with the history of conductive hearing loss were significantly poorer than the aged-matched controls (p = <0.001) in the three measures that contained spatial cues (DV90 condition, spatial and total advantage measures). There was no significant differences between the two groups in the SV0 condition or the talker advantage measure p= >0.05 (conditions in which no spatial differences were present). Significant correlations with degree of conductive hearing impairment (average hearing dBHL) were seen for the DV90 condition, spatial and total advantage measures. Plots of these relationships are shown in Figures 2, 3 & 4. Figure 2 Figure 3 Figure 4 Discussion and Conclusions r = -0.4 p = 0.02 r = -0.3 p = 0.04 r = -0.3 p = 0.04 Methods Acknowledgements Objectives Background and Rationale Results 2. Correlation between average hearing level and LISN-S measures