hrvatski

Zašto slabija razumljivost kod prezbiakuzije ?

By the increase of age, especially after the age of 60, hearing and intelligibility of speech gradually decrease. Hearing physiology data show that all structures of the auditory system, from peripheral to cortical ones, are of great importance for good speech intelligibility. Changes due to presbyacusis are described at all levels of the auditory system, but it is not known where the changes are the most frequent, whether the localisation of the impairment is changing with the increase of age, and what impairment is the most responsible for the decreasing of speech intelligibility. Hypotheses of this investigation were: dysfunction is the most marked at the periphery, especially at the receptors and at the cortical level of the auditory system ; retrocochlear impairment as well as subcortical dysfunction is rare ; tinnitus as a symptom of presbyacusis appears only exceptionally. By the method of random sampling, 109 subjects older than 60 (72% of them being females) divided into four groups, were tested. The auditory tests were: pure tone audiometry (TA), difference limen for pitch ( f) and for duration ( t) in acoustics, brainstem evoked response audiometry (ABR), testing of speech intelligibility in quiet (SGA), in noise (OGA), and with prolonged time between words (UGA) for phonetically balanced word lists, and for sentences pronounced at the normal rate (RS), sentences distorted by the time-compression technique (RU) and sentences in rapid alternating speech perception test (RASP). Comparison of test results and statistical analysis of results showed that by the increase of age, the peripheral auditory level becomes impaired, especially because of the impairment of receptors ; standard speech audiometry mostly corresponds to the receptors impairment and is quite insensitive to the detection of hearing central disorders. Testing of speech intelligibility for words in noise, for time- distorted sentences and for rapid alternating sentences were the best indicators of central presbyacusis. Brainstem evoked response audiometry and its comparison with the other findings showed that the deterioration of intelligibility most often is not the consequence of neural changes in the spiral ganglion and the changes at the brainstem level. The changes at this level appear rather rarely. With the increasing age cortical hearing impairment grows worse and it seems that it is the main reason for speech intelligibility deterioration in presbyacusis. Subortical changes are significantly weaker and only indirectly connected to other changes of the central auditory system. Before a hearing aid prescription, central auditory abilities have to be tested by words intelligibility in noise and by sentence testing. Depending on these findings, rehabilitation of selective hearing and/or processing time should be carried out.

razumljivost ; prezbiakuzija ; govorna audiometrija ; evocirani potencijali moždanog debla

nije evidentirano