In Brief:
One of the most commonly reported behavioral characteristics of auditory processing disorder (APD) is an inability to understand speech in background noise. Accurate assessment of speech perception in noise in the free-field may, however, be adversely affected by factors such as listener head movement. Performance on tests of speech understanding may also be influenced by factors such as the individual’s linguistic skills. The Listening in Spatialized Noise test (LISN) was developed using binaural audio engineering techniques to simulate a 3-D auditory environment under headphones. Performance on the LISN was assessed using difference scores, which measure the advantage gained from separating the target (children’s stories) from the noise (looped sentences) by + and -90°, whilst holding constant other factors such as the listener’s language proficiency. The spatial separation advantage in 20 adult listeners was comparable to measurements previously reported in the free-field, and decreased significantly as the voices of the speakers of the target stories and distracter sentences became more different from each other. In a separate study on 16 adults, no significant effect of learning was found on any LISN condition, and the test was considered to be a potentially valuable tool for assessing APD.
