Speech-in-Noise Test results of compensation claimants for noise induced hearing loss in Korean male workers: Words-in-Noise Test (WIN) and quick-Hearing-in-Noise Test (HINT).

BACKGROUND: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: 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.

Evaluation of wavelength-dependent hair growth effects on low-level laser therapy: an experimental animal study.

In this study, we aimed to investigate the wavelength-dependent effects of hair growth on the shaven backs of Sprague-Dawley rats using laser diodes with wavelengths of 632, 670, 785, and 830 nm. Each wavelength was selected by choosing four peak wavelengths from an action spectrum in the range 580 to 860 nm. The laser treatment was performed on alternating days over a 2-week period. The energy density was set to 1.27 J/cm(2) for the first four treatments and 1.91 J/cm(2) for the last four treatments. At the end of the experiment, both photographic and histological examinations were performed to evaluate the effect of laser wavelength on hair growth. Overall, the results indicated that low-level laser therapy (LLLT) with a 830-nm wavelength resulted in greater stimulation of hair growth than the other wavelengths examined and 785 nm also showed a significant effect on hair growth.

Diagnostic assay of trace lead in an ex vivo tissue using a combination electrode.

A voltametric diagnosis of trace lead was performed using macro type combination sensors of fluorine-doped graphite pencil electrodes (FPE). Two pencils were used as the reference and auxiliary instead of expensive Ag/AgCl standards and Pt counters. Under optimized conditions, a square wave (SW) stripping working curve was attained at 10-70 mg/L and a micro range of 10-70 µg/L. The developed sensor was not only inexpensive but also had a fast (90-s) accumulation time. An analytical detection limit of 10 µg/L was obtained. The results were applied to an ex vivo tissue and an artificial turf.