Experimental vibratory damage of the inner ear

Abstract

The aim of the experiment was to determine the effect of whole-body vibration on the inner ear. The investigations were carried out on 40 guinea pigs, subjected to sinusoidal vibration (10 Hz/5 mm/1.4 g rms) for 1 to 6 months in a noiseless apparatus. Cochlear microphonic measurements were done with a phase-sensitive detection technique for the levels 70, 80 and 90 dB and the frequencies of 0.26, 0.5, 1 and 2 kHz from the apex of the cochlea and for 4 and 8 kHz from the region of the round window. Analysis of 1,440 measurements suggested the possibility of damage appearing in the upper turnings of the cochlea. The subsequent morphological analysis was based on the estimation of the state of the hair cells (a three-degree scale of injury) in a Zeiss DSM 950 scanning microscope and of the structure of the fibers of the acoustic nerve in a Zeiss EM 900 transmission microscope. Vibration-induced changes were seen in all the examined inner ears of the experimental groups. Hair-cell damage was more often seen in the region of the apex, spreading gradually in the direction of the base and from the circumference (outer hair cells of the third row) to the modiolus. The most characteristic vibrational changes of the acoustic nerve fibers occurred in 100% of the examined myelin sheaths and were visible as decreases in their electrodensity. The changes in both the assessed elements of the inner ear appeared simultaneously but independently and were directly connected with the duration of the experiment. The results obtained allow an explanation of the mechanism of hearing loss in persons subjected to whole-body vibration. The damages done to the inner ear structures may cause a worsening of hearing there, especially in the low and medium frequencies.

RETRACTED ARTICLE: Assessment of the influence of whole body vibration on Cochlear function

“…Hamernik et al (1989) found that histological changes in the extent of the outer hair cell loss were responsible for the cochlear function shifts that occurred following vibration exposure conditions [11]. Bochnia et al (2005) asserted that vibration-induced changes were seen in all the examined inner ear areas, whereas hair-cell damage was more often seen in the apex, spreading gradually to the base and from the circumference (outer hair cells of the third row) to the modiolus [13]. Hamernik et al (1980) found that a damaged cochlea and vibrated membranous labyrinth were the main causes for vibration-induced cochlear function changes after low-frequency vibration [9].…”

“…Soliman et al (2003) reported that the exposure to vibration only led to enhancement of both DPOAE amplitude and signal to noise ratio [12]. Bochnia et al (2005) showed that vibration-induced damages to the inner ear structures may cause a worsening of hearing, especially at low and medium frequencies [13]. Therefore, a significant gap is evident in understanding the result of WBV exposure on cochlear function at realistic levels typically found in industrial settings.…”

Transmission of Acceleration From a Synchronous Vibration Exercise Platform to the Head During Dynamic Squats

“…Our results add further evidence that the head has a natural frequency between 20 and 30 Hz, and this frequency value may vary between individuals and the posture adopted. Since excessive vibration energy may have a detrimental effect on the visual, 16,17 auditory, 46 and vestibular systems, 47 these frequencies should be avoided.…”

Determining the Posture and Vibration Frequency that Maximize Pelvic Floor Muscle Activity During Whole-Body Vibration

“…A variety of previous studies reported that vibration transferred to the body caused adverse effects such as nausea and headache due to impaired vision, hearing loss, and strong stimuli to organs as vibration frequency increased [35–37]. In this study, RPE was highest at 22.67 at the frequency of 26 Hz, and some subjects complained of slight nausea and headache when WBV was applied at 26 Hz; they felt some pain at the knee joint and skin, had mild visual impairments, and had difficulty listening to the instructions of a computer program due to noises.…”