Effects of elevated serum lipids on the hearing threshold [a conventional extended high frequency audiometry study]

ABSTRACT

This study was designed to find out if hyperlipidemia can cause hearing affection and to evaluate the sensitivity of extended high frequency audiometry in early detection of hearing impairment. Audiological evaluation in the form of conventional pure tone air and bone conduction hearing threshold at octave frequencies was done. Extended high frequency hearing threshold audiometry measurement in dB-SPL at 9-18 KHz frequencies was also performed. Triglycerides had less damaging effect on hearing than cholesterol, however combined elevation had more drastic insult. LDL/HDL ratio is an important risk factor in hearing affection. LDL/HDL ratio <3 is a low risky affecting hearing at extended high frequencies at and above 11 KHz. LDL/HDL ratio between [3-6] is a moderate risky affecting hearing at and above 8 KHz. LDL/HDL ratio >6 is high risky, affecting hearing at all conventional and extended high frequencies. It was recommended to use extended high frequencies as a sensitive tool to detect early hearing affection in cases of hyperlipidemia. Treatment of hyperlipidemia should begin long before the evidence of diminished hearing in the high frequencies. Diet control should begin early in life as possible