The objective of the present study was to evaluate to what degree the function of the central auditory pathways influences the intelligibility of the speech in the patients suffering from the sensorineural loss of hearing (SNLH). The study included a total of 20 patients at the age varying from 31 to 80 years presenting with moderate to moderately severe symmetrical SNLN. All the patients were permanent hearing aid users. They underwent the standard audiological examination including pure-tone threshold and suprathreshold audimetries together with impedancemetry, the evaluation of the functional ability of the central auditory pathways with special reference to temporal resolution and differential frequency sensitivity, binaural integration, and the ability to distinguish a sound stimulus against the background noise. It has been found that the impaired intelligibility of the speech and the decreased efficiency of the hearing aids in the patients presenting with SNLH were attributable to the central auditory pathway disorders detected in 50% of the participants in the study. The strong correlation between the results of detection of the stimulus under conditions of tonal signal interference, the binaural integration test, and intelligibility of the speech in the users of hearing aids was documented.

Assessment of the condition of auditory analyzer central part functioning has been performed using of psychoacoustic tests that characterize human auditory system resolution, frequency differential response, binaural interaction and the ability to detect sound signal against the noise background. 20 patients with chronic bilateral symmetric sensorineural hearing loss at the age of 31 through 80 years old and 10 patients at the age of 20 through 25 years with normal hearing have been examined. Low informative value of the measurement of frequency difference thresholds and high importance of the gap detection test in diagnosing of central auditory disorders in patients with hearing loss have been noted. The studies on detection of a sound signal against the noise background made it possible to suggest a new test for assessment of central parts of auditory analyzer – the measurement of the useful signal threshold shift under the conditions of simultaneous presentation of tonal interference. Significantly greater signal threshold shifts against the noise background have been revealed in the patients with sensorineural hearing loss accompanied by impaired binaural interaction than in the patients with peripheral hearing loss and normal hearing.