Kohleovestibulyarnye disorders after operations on the stapes and their treatment

Auditory and vestibular divisions of the inner ear is a single system [1,4,5]. Anatomical and functional unit involves the mutual influence of labyrinthine systems.

In clinical practice, it shows a simultaneous violation of the auditory and vestibular function in various pathologies, which develops at the level of the inner ear: Meniere's disease, vestibular neurons, sudden deafness, perilimfaticheskaya fistula and others [2, 4, 5]. Such violations occur, as a rule, hearing loss, noise in the ear and vertigo. Dizziness associated with the change in the activity of vestibular apparatus, is systemic and manifested a condition in which a person seems to revolve around the objects around him in one direction, or he rotates in space. In contrast, non-systemic vertigo sensation of rotation is shown inside the head, a feeling of instability in space [2].

Modern methods of investigating auditory function allows us to prove the mutual influence of the vestibular and auditory ear labyrinth. In particular, these methods include registration of otoacoustic emissions.

Otoacoustic emissions - an objective method of assessing the functional state of organ of Corti [3]. One option is spontaneous otoacoustic emissions otoacoustic emissions.

Spontaneous otoacoustic emission occurs without an external acoustic stimulus, and very variable in frequency and number of peaks in different ears. This is an individual-specific types of emissions, which have a separate high frequency peaks. This unique type of emission lifetime does not change if there is no damage to the internal structure of the ear [6].

The mechanism of spontaneous emission otoakusticheskuoy is as follows: the oscillatory activity of groups of outer hair cells sets in motion the endolymph, which in turn stimulates the hair cells and thus closes the circle [6]. When you register a spontaneous otoacoustic emission spectra are analyzed, which revealed peaks that exceed background noise by 3-5 dB - these highs and call emission. The number of peaks is different and very individual.

The procedure for registration of spontaneous otoacoustic emissions is carried out without an external acoustic stimulation when installing sensitive microphone in the ear canal.

The frequency of this emission is usually located in the frequency range from 1 to 4 kHz, but, for some literature data, the spontaneous otoacoustic emission is the oscillatory process in the range of 0,3-8 kHz [3, 6].

Spontaneous otoacoustic emission is detected in approximately 40-60% of normal hearing individuals [6]. If you re-register the spontaneous otoacoustic emission is stable - 0.6% of the variability. At the same time drawing the spectra is very individual.

We studied the spontaneous manifestation of otoacoustic emissions when changing neurodynamics of vestibular receptor under the influence of caloric stimulation of the opposite ear in normal and various pathologies. Caloric test was carried out in one ear (t = 200C; 80,0 ml; 10s), and spontaneous otoacoustic emissions recorded on the opposite ear.

In 91% of the observed variation of spontaneous otoacoustic emissions: an increase in amplitude of the issue - 60% of cases, lower - 31%. Thus, the reported change in the function of outer hair cells (auditory receptors) in response to changes in the vestibular labyrinth of the activity under the influence of kalorizatsii. The results of this study suggest that the development of vestibular dysfunction due to changes in the cochlea, can affect the state of auditory function.

We analyzed the dynamics of auditory function in 37 patients with vestibular disorders after stapedoplastiki. The direct dependence of the results of operations of the severity and duration of vestibular disorders. The more active were vestibular disorders, the worse the results stapedoplastiki.

In severe short-term vestibular dysfunction (only operation) mainly observed violation of sensorineural hearing function type at high frequencies. During long-term vestibular disorders (more than 7 days) 78% of patients developed sensorineural hearing disturbance function at all frequencies.

The basis of treatment of functional disorders of the inner ear is the vasodilator action of various drugs. On the basis of the previously used histamine drug betahistine hydrochloride was developed, which not only improves blood flow to the cochlear, but also acts on the vestibular function. While working on the H3-receptors are regulated by the release of histamine and other neurotransmitters such as serotonin. The latter reduces the activity of the vestibular nuclei of the brain. Impact on H1 - receptors leads to local vasodilation and improved blood supply to the inner ear. Thus, the drug acts in a comprehensive and can improve auditory function not only by improving cochlear blood flow, but also due to suppression of vestibular activity.

We evaluated the clinical efficacy Betastin with vestibular dysfunction, which developed as a result of operations on the stapes (stapedoplastiki). 30 patients with vestibular disorders as a result of the transferred stapedoplastiki Betastin administered at a dose of 16 mg 3 times a day immediately after surgery and within one - two months after. 7 patients were noted vestibular disorders during the operation, 18 in the early postoperative period (up to 5 days after surgery), and 5 for 2 - 3 weeks after surgery. Receive Betastina will minimize vestibular disorders in early and late in the postoperative period, as well as stabilize faster auditory function. No patients with vestibular dysfunction in the early postoperative period is not revealed sensorineural hearing loss as a result of the operation. In 2 patients with vestibular dysfunction, which lasted 2-3 weeks, noted a violation of sensorineural hearing function type only in the zone of high frequencies.

Conclusions:

1. Experimentally proved the unity and mutual influence of the vestibular and auditory ear labyrinth.
2. Clinical observations support the experimental data: Vestibular dysfunction contributes hearing disorders. In particular, the presence of vestibular disorders in patients after stapedoplastiki is a poor prognostic sign and an indication for a specific drug therapy.
3. The presence of vestibular disorders after stapedoplastiki requires prompt conduct of medical therapy, particularly use of the drug Betastin, which is pathogenetically justified because the drug has an effect on kohleovestibulyarnuyu system, improving blood supply to the cochlea and vestibular suppressing activity
4. Betastin effective for the treatment of disorders kohleovestibulyarnyh after operations on the stapes.

References:

1. Gelfand SA Hearing: An introduction to psychological and physiological acoustics: Trans. from English. - Moscow: Meditsina, 1984. - 325s.
2. Sagalovich BM Meniere's disease, / BM Sagalovich, VT Palchun - M.: Medical News Agency, 1999. - 525s
3. Tavarkiladze GA Clinical audiology: Textbook / GA Tavarkiladze, TG Gvelisiani. - M., 1996. - 64C.
4. Etiopathogenic aspects in the treatment of disorders kohleovestibulyarnyh / TS Polyakov [and others] / / Vestn. Otolaryngology: Ros materials. Scientific-Practical. Conf. - 2003. - S. 182-185.
5. Brookler, KH Electronystagmography: vestibular findings in a patient with tinnitus / KH Brookler / / Ear Nose Throat. J. - 2003. - Vol. 82, № 9. - P. 673.
6. Manley, GA Otoacoustic emissions, hair cells, and myosin motors / GA Manley, L. Gallo / / J. Acoust. Soc. Am. - 1997. - Vol. 102, № 2 (Pt. 1). - P. 1049-1055.