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Biomedical subjects

H Harder

Publications and source records attributed to H Harder.

48 records · Page 3Linked to original sources
PubMed1982

Calculation of hearing results after tympanoplasty.

At present there is no universally accepted method for calculating hearing results after chronic ear surgery. In this study the methods most frequently used have been applied to a material of 105 tympanoplasties and compared to each other. In addition a comparison between pre- and post-operative bone conductions (BC) thresholds for calculating post-operative air-bone gaps has been performed using multiple regression analysis. The results lend support to the conclusion that BC thresholds will improve with surgery in successful cases and that the post-operative BC threshold is a closer approximation of the cochlear function than the pre-operative one and consequently should be used for gap calculations. However, until the masking procedures in audiometry are standardized, hearing gain may be regarded as the most satisfactory alternative for describing hearing results as it is based on the air conduction thresholds only. This method requires a careful description of pre-operative air and bone conduction thresholds.

Audiometry↗
PubMed1982

Reliability of bone-conducted electrocochleography. A clinical study.

The correlation between pure-tone bone conduction thresholds (BC) and thresholds obtained by electrocochleography with bone conducted stimulation (BC-ECoG) for 1, 2, 4 and 8 kHz was studied in 26 ears due for ear surgery. The correlations proved to be statistically highly significant and the results lend support to the conclusion that BC-ECoG can be considered to be well adapted for clinical use in cases where conventional audiometry has failed to reveal the capacity of the cochlea.

Audiometry↗
PubMed1980

Ossicular manipulation in chronic ear surgery. An electrocochleographic study.

Twelve patients were submitted to ossicular dissections for between 2 1/2 and 35 minutes during ear surgery. A comparison between premanipulatory and portmanipulatory electrocochleographic threshold determinations did not disclose any thrshold shifts. The results lend support to the conclusion that manipulations on ;the ossicular chain, performed with customary care, are less harmful to the inner ear than other generally recognized threats to the cochlea during surgery, eg, perilymph fistulae and acoustic traumas from the drill.

Cochlea↗
PubMed1980

Preoperative bone-conducted electrocochleography in otosclerosis.

Prior to surgery, pure-tone audiometry and bone-conducted (BC) electrocochleography (ECOG) were performed on 17 patients with preoperatively diagnosed otosclerosis. Short tone bursts, approximately 5 ms in duration and presented by means of a bone conductor on the exposed surface of the mastoid, were used as stimuli in BC ECOG. The thresholds thus obtained were compared by regression analysis with conventional psychoacoustic thresholds. Thresholds recorded at BC ECOG showed a close correlation to preoperative pure-tone BC thresholds, and there was no difference in predictability of postoperative hearing thresholds between preoperative BC ECOG and conventional preoperative pure-tone BC thresholds. The results lend support to the conclusion that BC ECOG, offering a monaural, objective estimation of cochlear function, is a valuable complement to conventional audiometry in the preoperative evaluation of hearing in otosclerosis.

Audiometry↗
PubMed1979

Hearing gain calculations after stapedectomy.

A comparison of the postoperative air-bone gaps to pre- and postoperative bone condition (BC) was made in two groups of patients with otosclerosis, 18 cases with poor preoperative BC thresholds and 15 cases with good preop, thresholds. The gaps to the postoperative BC showed less variation than the gaps to the preop. BC threshold, the postop. BC may therefore serve as a more stable and natural reference when calculating a postoperative air--bone gap.

Audiometry↗
PubMed1978

Allergy, otitis media and serum immunoglobulins after adenoidectomy.

The incidence of atopic disease and of episodes of otitis media, respiratory tract infections as well as levels of serum immunoglobulins were followed during 16 months after adenoidectomy in a consecutive group of 274 children. The total incidence of atopic disease was high (23.6%) at the start of the study and increased further to 39.0% during the study. Increased serum IgE levels, positive RAST tests and/or positive provocation tests were found before the onset of atopic symptoms in 13 out of the 19 children developing such symptoms during the observation period. Otitis media continued to occur in 42.9% of the children. The incidence of episodes of otitis media after the adenoidectomy was higher with lower age, a high number of episodes of otitis media before the operation and/or a history of atropic disease. None of the laboratory tests could predict subsequent episodes of otitis media. Protracted respiratory tract infections developed only in children with laboratory findings indicative of atopy. Serum IgE and IgM levels decreased significantly. No serious infections and no dysgammaglobulinaemias developed. Adenoidectomy seems to be a rather minor trauma from an immunological point of view, but further and controlled studies are needed concerning the possible clinical benefit of adenoidectomy in children with recurrent otitis media.

Adenoidectomy↗
PubMed1978

Longterm treatment with brompheniramine and phenylpropanolamine in recurrent otitis media--a double-blind study.

A double-blind study has been performed in 44 children with recurrent episodes of otitis media and/or secretory otitis media using a combined preparation of brompheniraminemaleate and phenylpropanolaminehydrocloride (Lunerin mite). No significant prophylactic effect was found on symptoms of respiratory tract infections or middle ear diseases during the trial period of nine months. The result suggests that further critical studies should be performed with such preparations which for the time being are used abundantly for the prevention of middle ear infections or effusions.

Brompheniramine↗
PubMedDate not supplied

Electrocochleography with bone-conducted stimulation. A comparative study of different methods of stimulation.

Due to the shortcomings of the conventional bone vibrators available at the present, electrocochleography with bone conducted acoustic stimulation has not found any clinical application despite the fact that methods for the procedure have been developed for some time. The most striking deficiencies of these vibrators are their unsatisfactory stimulus intensities and their lack of frequency specificity due to distortion. Driven by an a.c. signal, a piezoceramic accelerometer (A21T, D. J. Birchall Ltd.) was found to meet the requirements of clinical use giving satisfactory stimulus intensities with a minimum of distortion when attached to the mastoid process by means of a modified bone screw.

Acoustic Stimulation↗