Evaluating adaptive directionality using the Spatial Speech in Noise Test

A Spatial Speech in Noise test (SSiN) was developed by Bizley et al (2015, doi: 10.1177/2331216515619573) and offers the potential to assess both spatial discrimination and the ability to use spatial information for unmasking in clinical populations. The dual nature of the SSiN task has the potential to increase cognitive load, therefore reflecting more challenging listening scenarios. This double-blind study aims to determine whether the SSiN can be used to assess adaptive directionality in hearing aids. Six adult, experienced hearing aid users completed the SSiN with and without adaptive directionality activated. A focus group was carried out involving the SSiN participants to evaluate the usability of the SSiN. Adaptive directionality resulted in reduced reaction times to SSiN stimuli compared to the omnidirectional (OMNI) setting. There was no significant difference in word identification between conditions. Relative localisation was significantly worse in the adaptive directionality condition. During qualitative review, participants reported improvement indicators to enhance usability. SSiN findings include measures of spatial acuity based on word identification, spatial release from masking, relative localisation and reaction time (as a proxy for listening effort). The use of speech stimuli and multisource babble allows for an engaging task that replicates the challenges of real-world listening. Here, the SSiN has been used to assess adaptive directionality and findings are consistent with previous literature that suggests adaptive directionality reduces listening effort, even when there is no noticeable enhancement of speech perception. We have also presented some indicators to improve future applications of the SSiN.Funding:NIHR programme grant for applied research: 20160