Development of the North American Listening in Spatialized Noise-Sentences test (NA LiSN-S): sentence equivalence, normative data, and test-retest reliability studies.

BACKGROUND

The Listening in Spatialized Noise-Sentences test (LiSN-S) was originally developed in Australia to assess auditory stream segregation skills in children with suspected central auditory processing disorder (CAPD). The software produces a three-dimensional auditory environment under headphones. A simple repetition-response protocol is utilized to determine speech reception thresholds (SRTs) for sentences presented from 0 degrees azimuth in competing speech. The competing speech (looped children's stories) is manipulated with respect to its location (0 degrees vs. +90 degrees 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

The objective of this research was to develop a version of the LiSN-S suitable for use in the United States and Canada. The original sentences and children's stories were reviewed for unfamiliar semantic items and rerecorded by native North American speakers.

RESEARCH DESIGN

In a descriptive design, a sentence equivalence study was conducted to determine the relative intelligibility of the rerecorded sentences and adjust the amplitude of the sentences for equal intelligibility. Normative data and test-retest reliability data were then collected.

STUDY SAMPLE

Twenty-four children with normal hearing aged 8 years, 3 months, to 10 years, 0 months, took part in the sentence equivalence study. Seventy-two normal-hearing children aged 6 years, 2 months, to 11 years, 10 months, took part in the normative data study. Thirty-six children returned between two and three months after the initial assessment for retesting. Participants were recruited from sites in Cincinnati, Dallas, and Calgary.

RESULTS

The sentence equivalence study showed that post-adjustment, sentence intelligibility increased by 18.7 percent for each 1 dB increase in signal-to-noise ratio. Analysis of the normative data revealed no significant differences on any performance measure as a consequence of data collection site or gender. Inter- and intra-participant variation was minimal. A trend of improved performance as a function of increasing age was found across performance measures, and cutoff scores, calculated as two standard deviations below the mean, were adjusted for age. Test-retest differences were not significant on any measure of the North American (NA) LiSN-S (p ranging from .080 to .862). Mean test-retest differences on the various NA LiSN-S performance measures ranged from 0.1 dB to 0.6 dB. One-sided critical difference scores calculated from the retest data ranged from 3 to 3.9 dB. These scores, which take into account mean practice effects and day-to-day fluctuations in performance, can be used to determine whether a child has improved on the NA LiSN-S on retest.

CONCLUSIONS

The NA LiSN-S is a potentially valuable tool for assessing auditory stream segregation skills in children. The availability of one-sided critical difference scores makes the NA LiSN-S useful for monitoring listening performance over time and determining the effects of maturation, compensation (such as an assistive listening device), or remediation.