Background: The n200 project in Linköping Sweden was initiated to investigate the relationship between hearing, cognition and speech in noise. The initial 200 participants with hearing loss and hearing aids have been complemented by 200 participants without hearing loss. In addition, a smaller group of participants with hearing loss but without hearing aids was also found and tested when the group without hearing loss was recruited. The present study investigates the predictors of speech in noise in the 3 different groups for two different speech in noise tests, that is the Hearing In Noise Test (HINT) and the Hagerman sentences test. The Reading span task was used as an indicator of cognition, while better ear PTA was used as indicator of hearing ability.

Method: The two larger groups had comparable mean age (61 years), while the smaller group was older (69 years). Predictably, the hearing aid users had largest hearing impairment (37 dB better ear PTA), followed by the smaller group (28 dB) and the group without hearing impairment (10 dB). Correlational analyses were followed up by regression analyses to investigate the predictors of HINT and Hagerman in separate analyses.

Results and discussion: The pattern of predictors was different between the different groups and the two speech in noise tests. Reading span was a significant predictor for the Hagerman sentences but not the HINT test for all groups. Age and PTA were significant predictors for the hearing aid users and for the group without hearing loss, regardless of speech in noise test. For the smaller group, age but not PTA were significant predictors. It should be noted that the amount of explained variance was generally smaller for the HINT test and smaller for the groups without hearing aids. Results will be discussed in relation to the difference between the speech in noise tests and differences between the groups.