Analogue and Digital Hearing Aids. (Part 2). Audiometric Findings and
Relationship to Subjective Evaluation of Hearing Aids
Valvoda J., Kaňa R., Haas T.
ORL oddělení VFN, Praha, přednosta doc. MUDr. M. Hroboň, CSc. Ústav biofyziky 1. LF UK, Praha,přednosta doc. ing. M. Špunda, CSc. |
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Summary:
In a group of 114 patients, incl. 87 with analogue and 27 with completely digital hearing
aids the authors analyzed findings of speech audiometry without and with the hearing aid. They
used as a basis the previous analysis of subjective evaluation of hearing aids by the patients by
means of a questionnaire. They evaluated speech audiograms made during selection and allotment
of the hearing i.e. before they patient got used to it. The authors evaluated the threshold of
perception and maximum perception with the hearing aid and the resulting value of these parameters in dB and in four comparable groups of analogue and digital hearing aids (behind the ear
hearing aids for medium, severe and very severe losses and hearing aids inserted into the auditory
canal). A method of correction was elaborated for evaluating improvement of perception in patients
who did not attain 100% or not even 50% in speech discrimination. In general better results in speech
audiometry were achieved with digital hearing aids which is consistent with the subjective evaluation of hearing aids by patients. Statistically significant differences were confirmed only in the
group of suspended hearing aids for medium severe losses (p = 0.006, p = 0.039). The authors are
aware of the fact that mixed speech audiometry in a quiet environment has restricted possibilities
as regards evaluation of the advantages of digital and analogue technology for perceiving speech.
However they do not possess a test which can be evaluated better by statistical methods. It was also
found that patients who use their hearing aid more often (for longer periods of the day) achieved
a greater improvement of the threshold of perception and maximal perception with the hearing aid
during speech audiometry than patients who use the hearing aid only rarely (p = 0.001, and p = 0.006
resp.). This indicates that it is justified to use speech audiometry in a quiet environment as one of
the criteria for the selection of hearing aids. The authors did not prove a significant sexual
difference as regards improved perception. When investigating the effect of the patients’ age on
improved perception of speech with the hearing aid there was only one significant correlation, i.e.
a less marked improvement of speech receptia threshold in older patients (p = 0.035). It seems that
physiological ageing has a relatively small impact on the asset of the hearing aid at least in a quiet
environment.
Key words:
hearing aid, analoque and digital, speech audiometry, age, sex.
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