Pure-tone audiometry is used as a gold standard for hearing measurement. However, since communication in the work environment occurs in noise, it might be difficult to evaluate the actual communication ability accurately based on pure-tone audiometry only. Therefore, the purpose of this study is to evaluate speech intelligibility in noisy environments by using Speech-in-Noise Tests and to check its relationship with pure-tone audiometry.

From January 2017 to September 2018, for 362 workers who visited a university hospital for the purpose of compensating for noise-induced hearing loss, several tests were conducted: pure-tone audiometry, speech reception threshold, speech discrimination score, and Speech-in-Noise Tests (Words-in-Noise Test [WIN] and quick-Hearing-in-Noise Test [quick-HINT]). The subjects were classified into serviceable hearing group and non-serviceable hearing group based on 40 dB hearing level (HL) pure-tone average. In both groups, we conducted age-adjusted partial correlation analysis in order to find out the relationship between pure-tone threshold, speech reception threshold, speech discrimination score and WIN and quick-HINT respectively.

In non-serviceable hearing group, all results of partial correlation analysis were statistically significant. However, in serviceable hearing group, there were many results which showed little or no significant relationship between pure-tone threshold and Speech-in-Noise Tests (WIN and quick-HINT).

The relationship between Speech-in-Noise Tests and the pure-tone thresholds were different by the hearing impairment levels; in mild to moderate hearing loss workers, there was little or no relationship; in severe cases, the relationship was significant. It is not enough to predict the speech intelligibility of hearing-impaired persons, especially in mild to moderate level, with pure-tone audiometry only. Therefore, it would be recommended to conduct Speech-in-Noise Test.

The detection rate of hand-arm vibration syndrome (HAVS) is very low in South Korea compared with other countries. The absence of uniform consensus and guidelines for diagnosing HAVS has been presumed to be one of the reasons. The HAVS has various manifestations including cold intolerance and its severity can be measured using the cold intolerance symptom severity (CISS) questionnaire. This study aimed to determine whether the CISS questionnaire, being used as a screening tool, can aid in the early detection of HAVS.

A total of 76 male workers with vibration-induced symptoms were enrolled as the final study participants. To compare the CISS score of healthy individuals, 41 men who had never been exposed to local vibration were included in the study. In addition to the former medical questionnaire, the participants answered the CISS questionnaire. A statistical analysis was conducted to identify the association of CISS scores with vibration induced symptom and to determine its cut off value.

The reliability of the CISS questionnaire was proven to be good, with a total Cronbach’s alpha of 0.922. The mean CISS score of the exposed group increased in every vascular stage [stage 0 = 42.6 (18.5); stage 1 = 59.4 (14.1); and over stage 2 = 60.2 (21.6)]. They were significantly higher than that of the non-exposed group. The result was fairly consistent with those in the sensorineural stage. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and area under curve (AUC) of 30 were 88.5, 65.3, 76.1, 82.1 and 0.769, respectively. From the result of logistic regression, the adjusted odds ratio of both components increased by the CISS score grouped by 30s.

The self-reported CISS questionnaire, used to measure the degree of cold intolerance, showed high agreement with the Stockholm classification of HAVS. Hence, we recommend the use of this questionnaire to assess the level of cold intolerance among vibration-exposed workers and detect individuals who are at risk of vibration-induced impairment with a cutoff value of 30.

IRB No. 2018–07–040-001. Registered on 4 September 2018.