Effect of Noise on Speech Intelligibility and Perceived Listening Effort in Head and Neck Cancer.

Purpose This study (a) examined the effect of different levels of background noise on speech intelligibility and perceived listening effort in speakers with impaired and intact speech following treatment for head and neck cancer (HNC) and (b) determined the relative contribution of speech intelligibility, speaker group, and background noise to a measure of perceived listening effort. Method Ten speakers diagnosed with nasal, oral, or oropharyngeal HNC provided audio recordings of six sentences from the Sentence Intelligibility Test. All speakers were 100% intelligible in quiet: Five speakers with HNC exhibited mild speech imprecisions (speech impairment group), and five speakers with HNC demonstrated intact speech (HNC control group). Speech recordings were presented to 30 inexperienced listeners, who transcribed the sentences and rated perceived listening effort in quiet and two levels (+7 and +5 dB SNR) of background noise. Results Significant Group × Noise interactions were found for speech intelligibility and perceived listening effort. While no differences in speech intelligibility were found between the speaker groups in quiet, the results showed that, as the signal-to-noise ratio decreased, speakers with intact speech (HNC control) performed significantly better (greater intelligibility, less perceived listening effort) than those with speech imprecisions in the two noise conditions. Perceived listening effort was also shown to be associated with decreased speech intelligibility, imprecise speech, and increased background noise. Conclusions Speakers with HNC who are 100% intelligible in quiet but who exhibit some degree of imprecise speech are particularly vulnerable to the effects of increased background noise in comparison to those with intact speech. Results have implications for speech evaluations, counseling, and rehabilitation.