The acceptable noise level (ANL) test is used for quantification of the amount of background noise subjects accept when listening to speech. This study investigates Danish hearing-aid users' ANL performance using Danish and non-semantic speech signals, the repeatability of ANL, and the association between ANL and outcome of the international outcome inventory for hearing aids (IOI-HA).
ANL was measured in three conditions in both ears at two test sessions. Subjects completed the IOI-HA and the ANL questionnaire.
Sixty-three Danish hearing-aid users; fifty-seven subjects were full time users and 6 were part time/non users of hearing aids according to the ANL questionnaire.
ANLs were similar to results with American English speech material. The coefficient of repeatability (CR) was 6.5-8.8 dB. IOI-HA scores were not associated to ANL.
Danish and non-semantic ANL versions yield results similar to the American English version. The magnitude of the CR indicates that ANL with Danish and non-semantic speech materials is not suitable for prediction of individual patterns of future hearing-aid use or evaluation of individual benefit from hearing-aid features. The ANL with Danish and non-semantic speech materials is not related to IOI-HA outcome.
Rehabilitation of the majority of hearing handicapped in Sweden consists of hearing aid fitting, provision of technical devices and information during about four visits to a Hearing Centre. Generally there is no structured guidance of the hearing handicapped on how to proceed with the hearing aid at home between appointments. A programme of active fitting (AF) of hearing aids, with a task-oriented diary, 'Try Your Hearing Aid' as a basic part, was therefore developed. We conducted a series of studies from 1985 to 1988 with the aim of investigating the benefit and applicability of the programme. A total of 128 new hearing aid candidates participated in three studies at the Sahlgrens hospital and at four other hearing centres in smaller Swedish towns. In a controlled study the AF group was more positive to their hearing aids and to the fitting period after 10 months. They used their hearing aids more frequently and felt psychologically more secure with them. It was established that the AF programme could well be applied in the clinical routine for a majority of new hearing aid patients. Old age per se was not found to be a relevant exclusion criterion. The positive outcome of the AF programme has stimulated the Swedish Institute of the Handicapped to print 'Try Your Hearing Aid' with a manual, and to introduce it to all hearing centres in Sweden.
Etiological factors and otological and audiological findings were analysed retrospectively in 361 Finnish conscripts who had suffered acute acoustic trauma (AAT) from firearms shooting during their military service. The most common cause of AAT was shooting with hand-held weapons without ear-protectors (50%). Other common causal weapons were antitank guns (25%) and cannons (12%). Explosions had caused AAT in one-tenth of the cases. The tympanic membrane had been ruptured in 22 subjects (6%). The frequency at which hearing loss was severest was most commonly 6.0 kHz, followed by 8.0 kHz and 4.0 kHz in that order. Speech frequencies were involved in about 25% of the ears. A flat type of audiometric configuration was observed in about 20% and a rising type (low-tone loss) in about 5% of the ears. Impulse noise from large-calibre guns seemed to cause low-tone hearing loss more often than shooting with hand-held weapons.
The aetiology and risk indicators of hearing impairments of all types and degrees were studied in a 1-year birth cohort of 8713 children from northern Finland. The subjects (7 years of age) included in the clinical and audiometric examinations were recruited by standard clinical criteria, i.e. suspicion of parents according to a questionnaire, abnormal hearing screening result or a hearing impairment noted in hospital records (n = 541), and by random sampling from among the 8172 not suspected (n = 1009). One-hundred-and-one subjects in the group suspected of having hearing impairment and 27 subjects in the random sample eventually had hearing impairment. The aetiology could be defined in only 44.5% of the cases, ear infections being the most common. In this relatively small series, only a few risk indicators (congenital anomalies, meningitis and a history of ear discharge lasting for over 1 month) could be shown to be associated with impaired hearing in a logistic regression analysis.