[Distribution of main EEG rhythms in patients with initial neurosensory hearing disorders of vascular genesis].

Forty patients with neurosensory hearing disorders of vascular genesis were examined and divided into two groups. Patients with tone hearing disorders in conventional (0.125-8 kHz) and extended (9-16 kHz) frequency ranges entered group 1, those with such disorders in the extended range--group 2. Patients of group 1 had more pronounced cardiovascular dysfunction. Control group consisted of 15 persons with normal hearing. Electroencephalography (EEG) has shown that initial neurosensory hearing disorders were accompanied with redistribution of the main EEG rhythms especially in group 1. Compared to controls, these patients demonstrated significantly (p<0.05) reduced representation of alpha-rhythm while that of beta-activity rose showing involvement of cerebral cortical structures. Adequate preventive measures in patients with initial neurosensory hearing disorders of vascular genesis are able to protect such patients against development of neurosensory hypoacusis of vascular genesis.

[Value of cortical acoustic evoked potentials in sensorineural hypoacusis of vascular genesis]. / Pokazateli korkovykh slukhovykh vyzvannykh potentsialov pri sensonevral'noi tugoukhosti sosudistogo geneza.

Sixty patients 19 to 43 years of age (28 females and 22 males) with neurosensory hypoacusis (NH) of vascular genesis were examined using long-latent acoustic evoked potentials. The patients were divided into three groups. Group 1 consisted of 20 NH patients with initial hypertension, frequent headache, vertigo, sleeplessness, irritability but no complaints of hearing problems. Group 2 and 3 consisted of 20 NH patients each with initial and marked hearing problems, respectively. Compared to a control group of healthy subjects, all the examined vascular NH patients had longer latent periods of long-latent acoustic evoked potentials components P2 and N2, especially patients of group 1 in whom these periods made up 197.8 +/- 3.6 and 316.3 +/- 8.2 ms, respectively, in ipsilateral stimulation with the tone 1 kHz and 198.2 +/- 4.8 and 316.9 +/- 8.4 ms in 4 kHz stimulation. This suggests evident interest of cortical and subcortical structures of the acoustic analyzer in such patients. These values in group 1 differed from those in groups 2 and 3 in both types of stimulation (p < 0.05). These data deepen our knowledge about etiology of pathogenesis of neurosensory disorders in cardiovascular disorders and ascertain the role of vascular and neurogenic factors in their development.

[EEG and cardiac activity indices in patients with radiation-induced sensorineural hearing loss]. / Pokazateli élektroéntsefalografii i sostoianie serdechnoi deiatel'nosti u bol'nykh sensonevral'noi tugoukhost'iu radiatsionnogo geneza.

EEG was made in 47 patients with neurosensory hypoacusis (NSH) of radiation origin and 20 healthy subjects unexposed to radiation. These findings were compared to those on cardiac activity. The study shows that both in the temporal and occipital leads of patients with cardiac disorders alpha-rhythm amplitude and alpha-index are significantly less than in the control group. Thus, with deterioration of cardiac activity, NSH patients exposed to radiation exhibit more pronounced inhibition of bioelectric brain activity. This evidence should be considered in planning therapeutic and preventive measures in the above patients. The parameter of alpha-rhythm amplitude may be used in labour expertise of patients exposed to radiation.

[The relationship between the condition of the brain stem compartments of the acoustic analyzer and rheoencephalography in people who participated in the liquidation of the consequences of the Chernobyl' nuclear plant disaster]. / Vzaimosviaz' mezhdu sostoianiem stvolomozgovykh otdelov slukhovogo analizatora i dannymi reoentsefalografii u lits, prinimavshikh uchastie v likvidatsii posledstvii avarii na CHAES.

Pure-tone and speech threshold and suprathreshold audiometry, short-latent acoustic evoked potentials (SLAEP) and rheoencephalography (REG) were applied in examination of 67 patients with neurosensory hypoacusis (NSH) aged 21 to 45 years. These patients worked as wreckers in the zone contaminated with radionuclides 5 years and later after the Chernobyl accident. Relationships between functional condition of the truncal structures of the acoustic analyser and cerebral hemodynamics were studied. Correlation analysis has shown that there is close correlation between SLAEP and REG, especially in the vertebrobasillar area of cerebral circulation. The closest relations existed between the duration of the latent period of SLAEP wave V, interpeak interval I-V and rheographic index in the vertebrobasillar system. Combination of SLAEP and REG potentialities opens wide prospects for revelation of the key pathogenetic links for disorders of the acoustic system of unconventional origin, improves quality of these disorders diagnosis, promotes individual approach to therapy of such patients.

[Acoustic evoked potentials in patients with vocal problems in relation to their hearing in wide frequency range]. / Slukhovye vyzvannye potentsialy u bol'nykh s narusheniiami golosa v zavisimosti ot sostoianiia slukha v rashirennom diapazone chastot.

The function of different compartments of the acoustic analyser was assessed by the findings at tonal audiometry in standard and extended range of frequencies (10, 12, 14 and 16 kHz) as well as by characteristics of acoustic evoked potentials. A total of 62 patients with chronic vocal dysfunction (CVD) and 20 subjects with normal hearing and voice were examined. CVD patients were found to have: normal hearing both in standard and extended range of frequencies (25.8%); normal hearing in standard but defective one in extended range of frequencies (51.6%); defective hearing sensitivity to tones both in standard (4, 6 and 8 kHz) and extended frequency range (22.58%). CVD patients with abnormal hearing in the extended frequency range exhibited affection of the brain stem and cortical compartments of the acoustic analyser. Acoustic evoked potentials were especially abnormal in patients with high hearing thresholds (17.4 +/- 1.6; 25.8 +/- 1.9, 29.7 +/- 2.1 dB) in standard frequency range (4, 6 and 8 kHz), respectively. In such patients the disease ran a protracted course with frequent relapses. These findings can help in making decision on the treatment policy, occupational fitness expertise and selection of patients with vocal professions.

[Time aspects of short-latency acoustic evoked potentials in cleaners-up after the Chernobyl AES accident who have voice disorders]. / Vremennye pokazateli korotkolatentnykh slukhovykh vyzvannykh potentsialov u likvidatorov avarii na Chernobyl'skoi AES s narusheniem golosa.

Brain stem SLAEP were compared to EEG readings in patients with vocal problems consequent to low-dose radiation received after the Chernobyl accident. Versus control subjects, the patients had significantly (p < 0.01) longer latent periods of SLAEP waves 11 and V as well as the interpeak interval I-V. EEG findings indicated in patients changes in the diencephalic and diencephalic-stem regions, CNS dysfunction in the form of cortical structure irritation in the presence of low cerebral bioelectric activity. As shown by objective methods, the above patients with vocal problems have CNS disorders. This should be taken into consideration in planning treatment and incapacity decisions for such subjects.