[Evaluation of deprivation manifestations of the auditory system in patients with unilateral middle ear deafness before and after surgical therapy].

BACKGROUND: This paper will discuss whether long term conductive hearing loss leads to late onset auditory deprivation as described in the literature in patients suffering from bilateral sensorineural hearing loss and fitted with monaural hearing aids.

METHOD: The patients were examined using the Freiburg speech test in the undistorted and distorted forms (according to Dieroff 1985), and the pure tone threshold was ascertained for each patient. Thirty-six preoperative und postoperative results after tympanoplasty and stapes surgery were evaluated. Follow-up was performed six weeks and six months postoperatively. Twenty-one test persons with normal hearing were investigated.

RESULTS: Comparison showed that the quotient obtained from undistorted and distorted tests is significantly higher in the affected patients. We even observed a highly significant improvement of this quotient, the speech recognition score (according to Bönninghaus/Röser), and the pure tone threshold after surgery. Seventy-eight percent of our patients showed an improved quotient, and 73% attained a normal value. But in only 29% of all cases did we see a symmetrical quotient in both ears in this period of time. In the statistical evaluation, we were unable to demonstrate a correlation between the patient's age at that moment, the age at the beginning of hearing loss, and this echo quotient. There is also no correlation between the absolute and relative change of the echo quotient and the duration of hearing loss.

CONCLUSION: It was evident that the distorted Freiburg speech test is a good method to demonstrate the deprivation of the auditory system. We observed the improvement of the distorted Freiburger speech test at postoperative intervals of six weeks and six months. Hearing training should be applied after surgery in an effort to improve the hearing results.