Spatial auditory change detection in listeners with hearing loss

Everyday listening relies on the auditory system's ability to automatically monitor background ("non-target") sounds that lie outside the focus of attention to detect new or changing sources. Although change detection is a fundamental aspect of this situational awareness, little is known about how hearing impairment affects this ability. This study examined how variability in sensorineural hearing loss influences spatial auditory change detection. Older hearing-impaired listeners (N = 30) completed a spatial change detection task requiring them to identify the appearance of a new sound source within a complex spatialised acoustic scene. Hearing loss was characterised by three factors measured with standard clinical tests: audiometric hearing thresholds, sensitivity to small level changes, and sensitivity to spectrotemporal modulation. These factors were used to predict reaction time, hit rate, and false alarm rate. Listeners with poorer spectrotemporal sensitivity, higher audiometric hearing thresholds, and older age showed slower and less accurate detection, whereas sensitivity to small level changes did not predict outcomes. Detection also varied with spatial location, where appearing sources from behind were detected more slowly and less accurately than those from the front or sides. Numerical analysis using HRTFs suggested that these rear-field effects are not fully explained by acoustic level differences alone, indicating that attentional factors may play a role. These results reveal that hearing loss, age, and spatial factors jointly shape listeners' ability to monitor dynamic auditory scenes. Additionally, testing spectrotemporal sensitivity offers a promising clinical measure of non-speech auditory processing with relevance for hearing-aid fitting and situational awareness.