The interference of different background noises on speech processing in elderly hearing impaired subjects

The objective of the investigation is to study the interference of different background noises on speech processing. For this purpose speech recognition with the Hagerman test and a test battery with speech comprehension tasks (SVIPS) were performed in speech-weighted background noises varying in temporal structure, signal-to-noise ratio (SNR), and meaningfulness. With different test criteria and a score of perceived effort, the aim was to get a more complete picture of speech comprehension under adverse listening situations. Twenty-four subjects, aged 56-83 years, with a bilateral sensorineural hearing impairment, participated in the study. Differences in performance between the different background noises varied depending on the speech processing task, SNR, and on quantitative versus qualitative outcome measures. Age effects were seen in the Hagerman test and especially in background conditions of modulated noises (speech and reversed speech). Findings are discussed in relation to a hypothesis suggesting that masking and distraction interference from background noises on speech processing at peripheral, central auditory, and cognitive levels depends on the SNR used and the noise type and the listening task.