Measuring spatial processing abilities based on attention modulating tasks

Abstract

Improvement in speech intelligibility can occur when the target talker is spatially separated from competing talkers. Reduction in an individual's hearing ability and working memory (WM) capacity are hypothesized to be two of the major reasons for reduction in performance in a complex listening environment. This study estimated working memory capacity based on a divided attention version of the classic spatial release from masking task using the Coordinate Response Measure (CRM) as speech stimuli. WM capacity was estimated with a speech source presented directly ahead of the listener and two additional speech sources either colocated at 0 deg azimuth angle or symmetrically separated by 30 deg with various amounts of temporal overlap between the speech sources. The listeners were instructed to identify all three color/number combinations presented. Adaptive procedures were used to obtain the maximum amount of temporal overlap at which listeners were still able to correctly identify the speech source presented directly ahead of the listener 50% of the time. Initial analyses of the data indicated strong relationship between SRM and temporal overlap thresholds indicating that SRM is driven by the listeners' ability to modulate their attentional mechanisms.