This study investigated the psychometric adequacy of the (modified) Amsterdam Inventory for Auditory Disability and Handicap ((m)AIAD). The original version of the AIAD was developed by Kramer et al in 1995. Special emphasis was placed on the statistical aspects of the scores, because these properties place limits on the clinical utility of the instrument. The AIAD is a self-assessment questionnaire that consists of 30 questions covering all the relevant factors of disability in individual hearing functioning in daily life. This paper reports data from 94 subjects, aged 17-65 years, with different hearing abilities, who completed a modified version of the AIAD and the Hearing Disability Questionnaire (HDQ), on two occasions 1 month apart. The psychometric adequacy of the AIAD was determined by measuring its reliability and validity. Factor analysis was performed, and the reliability was tested by measuring internal consistency, split-half correlation, and test-retest reproducibility. The validity was tested by measuring construct and criterion validity. The results showed that the reliability of the (m)AIAD was highly satisfactory, with good internal consistency, high split-half correlations, and high test-retest correlations. Construct validity showed a high correlation between scores on the (m)AIAD and scores on the HDQ. Criterion validity showed a moderate but significant correlation between scores on the (m)AIAD and hearing thresholds in dB HL.

This study investigates the test-retest distributions and the interval for true score change of the (modified) Amsterdam Inventory for Auditory Disability and Handicap [(m)AIAD], when the latter is used to measure the effect of an intervention. In a previous study the reliability and validity of the (m)AIAD in a cohort of hearing impaired patients were found to have satisfactory high values. In this prospective study, 66 patients underwent a tympanoplasty operation. Preoperatively and postoperatively pure tone audiometry was performed, and at the same time the subjective hearing ability was established by means of the (m)AIAD. The correlation between threshold change and score change was 0.35 (Pearson's r). Scores on the (m)AIAD had to change by at least 16 to be qualified as a true change. For only nine of 66 subjects this criterion was fulfilled. No clear relation exists, except for these nine subjects, between threshold change and score change in this patient population. The study also shows that disability questionnaires have their limitations, when using them to measure the result of a medical intervention in an individual patient.

The biocompatibility of hydroxylapatite-polyethylene composite implants (HAPEX, Smith and Nephew) was investigated in this study. Eleven middle ear prostheses, removed during revision surgery, have been examined by light microscopy, transmission electron microscopy and scanning electron microscopy. The results show that the middle ear prostheses become overgrown by fibrous tissue inside a thin epithelial layer. In some cases the prosthesis is covered by fibrous tissue without an outer layer of epithelial cells. No arguments have been found for the accumulation of macrophages and foreign body giant cells associated with a foreign body reaction to the material. Therefore, hydroxylapatite-polyethylene composite implants (HAPEX, Smith and Nephew) would seem to be very suitable for reconstructive middle ear surgery.

In this experimental animal study, a cartilage disk was interposed between a synthetic middle ear prosthesis and the tympanic membrane in guinea pigs to investigate its effect on the extrusion process of the implant. Two groups of guinea pigs were studied. One group consisted of animals in which the prosthesis was directly in contact with the tympanic membrane, and the other group consisted of animals in which a cartilage disk had been inserted between the head of the prosthesis and the tympanic membrane. Before histologic processing, in situ inspection was performed with an operating microscope. After fixation and embedding, light microscopic and transmission electron microscopic examination were performed. We studied the histopathologic aspects of the tympanic membrane with regard to the protrusion and extrusion processes of the middle ear implant. In this experimental model, protrusion and extrusion of a hydroxylapatite middle ear prosthesis was greatly reduced by interposition of a cartilage disk. Further clinical evaluation of these experimental results is needed in the human middle ear.

No abstract