Background: The Listening in Spatialized Noise--Sentences test (LISN-S) is a revised version of the Listening in Spatialized Noise (Continuous Discourse) test (LISN; Cameron et al, 2006a). The software produces a three-dimensional auditory environment under headphones and was developed to assess auditory stream segregation skills in children. A simple repetition response protocol is utilized to determine speech reception thresholds (SRTs) for sentences presented from 0 degree azimuth in competing speech. The competing speech is manipulated with respect to its location in auditory space (0 degree vs. + and -90 degrees azimuth) and the vocal quality of the speaker(s) (same as, or different to, the speaker of the target stimulus). Performance is measured as two SRT and three advantage measures. The advantage measures represent the benefit in dB gained when either talker, spatial, or both talker and spatial cues combined are incorporated in the maskers.
Purpose: To document LISN-S performance in a group of nine children with suspected (central) auditory processing disorder ([C]APD), who presented with difficulties hearing in the classroom in the absence of any routine audiological or language, learning or attention deficits to explain such a difficulty (SusCAPD group). The study also aimed to research the effect of higher-order deficits on LISN-S performance in a group of 11 children with a range of documented learning or attention disorders (LD Group). Correlation between performance on the LISN-S and a traditional (C)APD test battery was also compared.
Research design: In a descriptive design, SusCAPD and LD group performance on the LISN-S was compared to published normative data from 70 age-matched controls. A correlational design was used to compare performance on the various tests in the traditional (C)APD battery to the SRT and advantage measures of the LISN-S.
Results: There were no significant differences between the SusCAPD, LD, or control groups on the conditions of the LISN-S where both the target and maskers emanated from 0 degree azimuth (low-cue SRT, p = 0.978; talker advantage, p = 0.307). However, there were significant differences between groups on the performance measures where the maskers were separated from the target by + and -90 degrees. Post hoc tests revealed that there were no significant differences between the LD group and controls on any of these measures. There were, however, significant differences between the SusCAPD group and the controls on all the conditions where the maskers were spatially separated from the target (high-cue SRT, p = 0.001; spatial advantage, p < 0.0001; total advantage, p < 0.0001). The LISN-S did not correlate significantly with any test in the traditional test battery, nor were the nonspatial and spatial performance measures of the LISN-S correlated.
Conclusions: The study supports the hypothesis that a high proportion of children with suspected (C)APD have a deficit in the mechanisms that normally use the spatial distribution of sources to suppress unwanted signals. The LISN-S is a potentially valuable assessment tool for assessing auditory stream segregation deficits, and is sensitive in differentiating various forms of auditory streaming.