Correlation between plasma levels of radical scavengers and hearing threshold among elderly subjects with age-related hearing loss.

CONCLUSION: Low plasma melatonin is significant in the development of high frequency hearing loss (HL) among the elderly. OBJECTIVE: To determine the correlation between hearing threshold and the plasma melatonin and ascorbic acid (vitamin C). METHODS: This was a cross-sectional study involving 126 apparently healthy elderly subjects, 59 males and 67 females, aged >60 years. Subjects underwent pure tone audiometry and plasma melatonin and vitamin C were assayed using high-performance liquid chromatography. RESULTS: The mean ± SD of plasma melatonin among the subjects with normal hearing (NH) (0-30 dB) and those with HL in the speech frequencies was 18.3 ± 3.6 µg/L and 16.4 ± 4.7 µg/L, respectively. In the high frequencies the values were 17.7 ± 6.2 µg/L and 13.1 ± 6.4 µg/L for NH and HL, respectively. For vitamin C, the mean ± SD among subjects with NH and those with HL in the speech frequencies were 1.2 ± 0.2 µg/L and 1.0 ± 0.1 µg/L, respectively. In the high frequencies, the values were 1.0 ± 0.2 µg/L and 0.9 ± 0.3 µg/L for NH and HL, respectively. Among subjects with high frequency HL, Spearman's correlation revealed significant correlation between increasing hearing threshold and melatonin (correlation coefficient = -0.30, p = 0.01), but not for vitamin C (correlation coefficient = -0.12, p = 0.22). Linear regression, adjusting for age, still revealed significant correlation between the melatonin (correlation coefficient = -0.03, p = 0.00) and hearing threshold in the high frequencies.

[Study on relation of kidney-deficiency with hearing damage and serum trace elements in patients with chronic nephropathy].

The hearing and serum trace element of 73 cases of chronic nephropathy were measured. Results showed that the incidence of hearing damage in high frequency was 68.5% with a mean hypoacusis of 35.1 +/- 6.1 dB, while in 55 patients of Kidney Deficiency type, the incidence of hearing damage in high frequency was 83.6%, it was significantly higher than that in patients without Kidney Deficiency. The serum levels of trace elements (iron and zinc) in patients with Kidney Deficiency were lower than that of normal level and in patients without Kidney Deficiency, and the decrease of serum iron was directly proportional to the degree of hearing damage. There were close relationship between the Kidney Deficiency with the hearing damage as well as the serum levels of iron and zinc.

Ototoxicity monitoring with ultra-high frequency audiometry in peritoneal dialysis patients treated with vancomycin or gentamicin.

Ototoxicity affects the higher frequencies first and extends to the lower frequencies during continuation of the ototoxic treatment. Peritonitis due to continuous ambulatory peritoneal dialysis (CAPD) regularly demands ototoxic antibiotic treatment, e.g. with gentamicin and vancomycin. In this study ultra-high frequency audiometry (10-20 kHz), 'normal' audiometry (0.125-8 kHz) and registration of blood concentrations of the antibiotics were used to assess ototoxic hearing loss during treatment of CAPD patients with peritonitis.