Effect of atmospheric pressure on hearing in patients with Menière's disease

Hypobaric pressure exposure effects on cochlear frequency selectivity in fluctuating, low-frequency hearing loss

Aim:

To study the effects of hypobaric pressure chamber exposure on the cochlear frequency selectivity of subjects with monaural, fluctuating, low-frequency hearing loss, such as occurs in Ménière's disease.

Methods:

We used a hypobaric pressure chamber to create relative underpressure in the ear canal, in order to impose positive pressure gradients on the inner ear. Psychophysical tuning curves, transiently evoked otoacoustic emissions and speech recognition scores in noise were measured in 10 subjects with fluctuating, low-frequency hearing loss, before and after pressure exposure.

Results:

After the exposure, subjects’ overall pure tone averages showed no improvement, but individual results showed improved speech recognition scores in noise (six subjects), increased transiently evoked otoacoustic emission strength (three subjects) and increased psychophysical tuning curve steepness (two subjects). Deteriorations were also seen, mainly in psychophysical tuning curves. No association could be established between the different tests, and the measured parameters could not predict subjective improvement.

Conclusion:

The results suggest variable effects of hypobaric pressure exposure on inner-ear physiology.

Local Overpressure Treatment Reduces Vestibular Symptoms in Patients with M??ni??re's Disease: A Clinical, Randomized, Multicenter, Double-Blind, Placebo-Controlled Study

OBJECTIVES

To evaluate the efficacy of a new device, the Meniett, in the treatment of Meniere's disease. The device delivers pressure pulses to the middle ear through a ventilating tube in the tympanic membrane at a frequency of 6 Hz for 0.6 second. After rising to a pressure level of 1.2 kPa, the pressure oscillates between 0.4 and 1.2 kPa. It is believed that the pressure changes are conveyed to the inner ear, inducing a transport of fluids via the pressure outlets and thus reducing the endolymphatic hydrops.

STUDY DESIGN

A clinical, randomized, multicenter, double-blind, placebo-controlled study. A total of 40 patients were included that had active Meniere's disease according to American Academy of Otolaryngology-Head and Neck Surgery criteria, aged between 20 and 65 years, with a history of at least eight attacks during the past year. After insertion of the ventilation tube, the patients should have had attacks of vertigo for 2 months before entering the study.

OUTCOME MEASURES

Primary study endpoints were change in frequency of vertigo, change of functionality profile, and change in patient perception of vertigo (visual analogue scale); secondary endpoints were perception of tinnitus, aural pressure, and hearing, as well as an audiologic evaluation of hearing before and after the treatment period.

RESULTS

The functionality level improved statistically significantly in the active group compared with the placebo group (p=0.0014), as did the visual analogue scale evaluation of vertigo (p=0.005). There was a trend toward a reduction of the frequency of vertiginous attacks that was not significant (p=0.090). With regard to the secondary endpoints, there was no statistical difference between active and placebo groups.

CONCLUSION

Local overpressure treatment is a novel treatment that is noninvasive, nondestructive, and safe. It significantly reduces vestibular symptoms in patients with Meniere's disease. The Meniett was cleared by the Food and Drug Administration in 2000.

Electrocochleographic and audiometric evaluation of hypobaric effect in Meniere's disease

OBJECTIVES

To elucidate the effects of hypobaric pressure on cochlear hydrodynamics in patents with well-defined Meniere's disease.

DESIGN

Sixteen patients were consecutively selected. Elevated hearing threshold levels and pathological transtympanal electrocochleography (tt-ECOG) were confirmed at the day of trial. The patients were exposed to repeated episodes of hypobaric pressure in a pressure chamber. The rate (20 daPa/s) and magnitude (-285 daPa) of chamber pressure change were low. The induced tympanic overpressure (+185 daPa) was continuously monitored and any tympanic equilibration was avoided.

METHODS

The results of Bekesy and speech audiometry as well as tt-ECOG performed immediately before and after exposure were compared. The importance of chamber pressure change, number of hypobaric episodes, duration of exposure, and the induced relative tympanic overpressure was tested.

RESULTS

It is shown that the relative tympanic overpressure is the most important factor to affect the cochlear hydrodynamics. Higher relative overpressure was associated with improvement of hearing threshold levels, while the ECOG results tended to improve with lower induced tympanic overpressure.

CONCLUSION

The importance of tympanic overpressure shown in this study is in agreement with previous findings from hypobaric animal experiments. The inverse relation of psychoacoustic and ECOG tests suggests that the two methods evaluate different parameters, perhaps contributing differently to the physiology of hearing.

Alternobaric and hyperbaric oxygen therapy in the immediate and long-term treatment of Menière's disease

Forty-five patients suffering from Menière's disease were submitted to pressure chamber therapy: 20 with constant pressure (2.2 ATA, hyperbaric treatment) and 25 with continuous variations in pressure levels (from 1.7 to 2.2 ATA, alternobaric treatment). Oxygenation therapy consisted of one session per day lasting 90 minutes for 15 days during the acute attacks followed by five consecutive sessions per month during a follow-up of two years. For a control group we used 18 patients treated with 10 per cent intravenous glycerol during the acute episode and 8 mg tid of betahistine thereafter. We compared hearing loss, vertigo and tinnitus in the three groups 15 days after starting treatment and at the end of the follow-up, according to the criteria suggested by the 1995 Committee on Hearing and Equilibrium. We found no statistically significant differences in recovery from the cochlear-vestibular symptoms in the three groups at the end of the first 15 days of therapy, whereas hyperbaric and, in particular, alternobaric treatment permitted a significant control of the principal attacks of vertigo during the follow-up period. Hearing loss also showed a more significant and more persistent improvement in the patients treated with alternobaric oxygenation compared to the patients in the other two groups.