Hearing Impairment in Crowdsourced Speech Quality Assessments: Its Effect and Screening with Digit Triplet Hearing Test

The method of crowdsourcing (CS) for subjective speech quality assessments (SQA) has been refined by identifying influencing factors, examining their effect and developing mitigation methods. Hearing impairment, has been identified as a possible influencing factor, and screening methods like the P.808 Toolkits Digit Triplet Hearing Test (DTHT) has been developed. To investigate the effect of hearing ability on SQAâ€(TM)s and to evaluate the DTHT we simulated a crowdworking setup, in which participants with unimpaired hearing, impaired hearing, and simulated hearing impairment completed both SQA and DTHT. Our results show significant differences between the speech quality ratings in the SQA based on hearing ability. Furthermore, the DTHT produces significantly different results for unimpaired and hearing impaired participants in a calm and noisy environment, up to a noise level of 57 dB(A). For the DTHT we calculated a screening threshold of -7.48 dB SNR with 79.2% accuracy. We conclude that hearing ability screening is necessary for CS SQA and that the DTHT is an adequate method for this task.