Objective: The aim of the current study was to assess aided speech-in-noise outcomes and relate those measures to auditory sensitivity and processing, different types of cognitive processing abilities, and signal processing in hearing aids.

Material and method: Participants were 200 hearing-aid wearers, with a mean age of 60.8 years, 43% females, with average hearing thresholds in the better ear of 37.4 dB HL. Tests of auditory functions were hearing thresholds, DPOAEs, tests of fine structure processing, IHC dead regions, spectro-temporal modulation, and speech recognition in quiet (PB words). Tests of cognitive processing function were tests of phonological skills, working memory, executive functions and inference making abilities, and general cognitive tests (e.g., tests of cognitive decline and IQ). The outcome test variables were the Hagerman sentences with 50 and 80% speech recognition levels, using two different noises (stationary speech weighted noise and 4-talker babble), and three types of signal processing (linear gain, fast acting compression, and linear gain plus a non-ideal binary mask). Another sentence test included typical and atypical sentences with contextual cues that were tested both audio-visually and in an auditory mode only. Moreover, HINT and SSQ were administrated.

Analysis: Factor analyses were performed separate for the auditory, cognitive, and outcome tests.

Results: The auditory tests resulted in two factors labeled SENSITIVITY and TEMPORAL FINE STRUCTURE, the cognitive tests in one factor (COGNITION), and the outcome tests in the two factors termed NO CONTEXT and CONTEXT that relates to the level of context in the different outcome tests. When age was partialled out, COGNITION was moderately correlated with the TEMPORAL FINE STRUCTURE and NO CONTEXT factors but only weakly correlated with the CONTEXT factor. SENSITIVITY correlated weakly with TEMPORAL FINE STRUCTURE and CONTEXT, and moderately with NO CONTEXT, while TEMPORAL FINE STRUCTURE showed weak correlation with CONTEXT and moderate correlation with NO CONTEXT. CONTEXT and NO CONTEXT had a  moderate correlation. Moreover, the overall results of the Hagerman sentences showed 0.9 dB worse SNR with fast acting compression compared with linear gain and 5.5 dB better SNR with linear  gain and noise reduction compared with only linear gain.

Conclusions: For hearing aid wearers, the ability to recognize speech in noise is associated with both sensory and cognitive processing abilities when the speech materials have low internal context. These associations are less prominent when the speech material has contextual cues.