Birger Christensen

Potential Language and Attentional Networks Revealed through Factor Analysis of rCBF Data Measured with SPECT

We used changes in regional cerebral blood flow (rCBF) to disclose regions involved in central auditory and language processing in the normal brain. rCBF was quantified with a fast-rotating, single-photon emission computerized tomograph (SPECT) and inhalation of 133Xe. rCBF data were obtained simultaneously from parallel, transverse slices of the brain. The lower slice was positioned to include both Brocas and Wernickes areas. The upper slice included regions generally regarded by neurobehaviorists as less related to primary auditory or linguistic functions. We presented three types of auditory stimuli to ten healthy, young volunteers: (a) diotically presented Danish speech, (b) dichotic word stimulation, and (c) white noise. Wilcoxons signed ranks sum test revealed increased rCBF in language-related areas of cortex, viz., Wernickes area and its right-sided homologous area as well as in Brocas area (left hemisphere), when subjects listened to narrative speech, compared to white noise (baseline). No significant rCBF differences were detected with this test during dichotic stimulation vs. white noise. A more sophisticated statistical method (factor analysis) disclosed patterns of functionally intercorrelated regions. The factor analysis reduced the highly intercorrelated rCBF measures from 28 regions of interest to a set of three independent factors. These factors accounted for 77% of the total variation in rCBF values. These three factors appeared to represent statistical analogues of independent brain networks involved in (I) auditory/linguistic, (II) attentional, and (III) visual imaging activity.

Hearing in the Elderly ≥ 80 Years of Age Prevalence of Problems and Sensitivity

This article is part of an epidemiological study on hearing in an urban population > or = 80 years of age, and concentrates on the prevalence of hearing problems and hearing sensitivity as a function of age and gender. Prior to the study, 2915 residents aged 80+ from the Valby area in Copenhagen were selected for investigation and subdivided into two groups. The first group, comprising n = 859 subjects previously provided with HA, and the second group, resulting from an invitation mailed to n = 565 subjects, were matched according to the age and gender distribution of the population, i.e. 24% males and 76% females. Among these, only 41% at a median age of 84 years, range 80-96, accepted the invitation, being significantly younger than the non-attenders. The estimated prevalence of self, reported hearing problems ranged between 33 and 66%, increasing with increasing age. Significant differences were found in the hearing sensitivity as a function of gender, i.e. the hearing in the low-frequency area < 1 kHz is better, whereas the hearing sensitivity at > 2 kHz is significantly worse in males compared with females. The speech recognition score (SRS) was significantly higher in females compared with males, and a comparison between ears supports the finding that the right ear speech recognition score is better than the left. The study demonstrates the difficulties in obtaining reliable epidemiological data on the hearing in the elderly > or = 80 years, which represents an obstacle for the planning of appropriate hearing health services directed towards this age group, and collaborative studies are suggested in order to accumulate more knowledge.

Training and Employment in Hearing-Impaired Subjects at 20–35 Years of Age

This study was undertaken in order to evaluate the training and the employment situation in a cohort of hearing-impaired subjects born between 1955 and 1970. A sample of 288 persons was collected from 33,352 consecutive patients with hearing thresholds > 20 dB HL in at least one pure-tone frequency (250-8000 Hz) in one (right/left) ear and all living in the city of Copenhagen at the time of data collection. The total sample of 288 persons was divided into two groups according to age at onset of their hearing impairment: group 1 comprised 165 persons with congenital/early acquired hearing loss (before 2 years of age); group 2 comprised 123 subjects with acquired hearing loss (after 2 years of age), acting as a reference group. A questionnaire was mailed to all 288 subjects meeting the inclusion criteria, achieving 218 responses (76%). The questionnaire evaluated the educational and employment situation and revealed significant differences, training within crafts being more common in group 1 in contrast to training at university level being more common in group 2. A frequency of 31%/29% respectively of unemployment at the time of the questionnaire was found in the two hearing-impaired groups, compared with 12% in an age-matched background population. A subdivision according to hearing thresholds indicated that the degree of hearing loss is of importance for education at university level. A question concerning general well-being showed that the majority of hearing-impaired persons, irrespective of age of onset of their hearing impairment, are satisfied with their life.

In-the-ear Hearing Aids the Use and Benefit in the Elderly Hearing-Impaired

Preliminary clinical experiences with in-the-ear hearing aids (ITE-HAs) have been promising, and a beneficial effect has been demonstrated in younger hearing-impaired subjects. However, the subjects applying for audiological examination and rehabilitation are predominantly elderly people (i.e. greater than or equal to 70 years). The present questionnaire examination was performed in order to evaluate the use and benefit of ITE-HAs also in the elderly hearing-impaired, and compare with the effect in younger subjects. An extensive questionnaire was sent 6 months after hearing aid fitting to all patients fitted with ITE-HAs. A total number of 693 subjects corresponding to 80% responded to the questionnaire. 70% of the patients are greater than or equal to 70 years and 23% are above the age of 80 years. The results demonstrate that the elderly hearing-impaired use the hearing aids predominantly in situations when listening to television and in small groups; 64% use their hearing aids the whole day and only 6% never use the aids; with increasing age were indicated increasing handling problems, both concerning change of battery, handling of volume control, and insertion of the aid into the ear canal. Only 8% of the patients were dissatisfied with the cosmetic appearance of the hearing aids, the dissatisfaction being more frequent in the young age group below 70 years (16%) than above the age of 70 years (9%). It is concluded that also the elderly hearing-impaired use and benefit from ITE-HAs.

The Use and Benefit of In-the-ear Hearing Aids A four-year follow-up examination

The present investigation was performed in order to evaluate the use and benefit of in-the-ear hearing aids (ITE-HAs) after a 4-year observation period, and to examine the validity of this type of hearing aid. A sample of 537 subjects still in possession of ITE-HAs, fitted in 1985, responded to a postal questionnaire in 1989, including questions identical to the first follow-up in 1985. The 537 persons correspond to 60% of the originally fitted sample of 894 subjects. The investigation indicated that no change in the use of or benefit from ITE-HAs has taken place during a 4-year period, and in addition the manipulative skills of the hearing aid users did not improve. However, the overall frequency of handling problems is low, though with a tendency to increase in the age group above 75 years. It is concluded that the use of and benefit obtained with ITE-HAs remains unchanged over a 4-year period; that the use and benefit is similar in the age groups below and above 75 years of age; that the ITE-HAs seem to be fairly stable during a 4-year period.

Epidemiology of permanent hearing impairment in children in relation to costs of a hearing health surveillance program

The objective of this investigation was to estimate the prevalence of any permanent hearing impairment (PHI) in the right and or left ear based on children included into a surveillance program in the local pediatric hearing health services (PHHS), and to analyze the costs, generated by the children. The study is a cross-sectional study, which is part of a major prospective study directed towards delineation of all aspects of pediatric audiology. The present sample comprises 228 children, 115 males and 113 females, at a median age of 13 years, range 0-24, and involves all children living in the health district of the City of Copenhagen, who are or have been included in a local surveillance program with one (school children) or two (pre-school children) annual visits for children with PHI > 20 dB HL at any frequency in either the left or the right ear. The prevalence of PHI increases with increasing age, reaching its peak in the age band 10-14 years exhibiting a rate of 5.32 1000 (95% confidence intervals: 4.27 to 6.64 per 1000). The estimated incidence of PHI in a ten year cohort born 1977-1986 is 325 100 000 children born (95% confidence intervals: 277 to 382 per 100 000). The most frequent factor causing PHI is inheritance, showing an increase from 20% in 1977-1981 cohorts, to 37% in 1982-1986 cohorts. The costs involved in the PHHS concerning PHI varies considerably from approximately 345 000 to 990 000 DKr.. depending on the model used for the economical analysis. No data on cost-benefit or cost-effectiveness can be given in this context, and it is concluded that the documented changes in the prevalence and causes of PHI in children emphasize the need for a continuous monitoring and evaluation of the epidemiological figures.

Hearing instruments and health technology--an evaluation.

This contribution compares a currently worn hearing instrument (i.e. R-HI) with a programmable multiband full-dynamic range compression behind-the-ear HI (i.e. T-HI), based on subject preference for HI, and, in addition, compares the preference for a linear/ non-linear amplification-mode (i.e. L-mode/C-mode). Finally, it evaluates some health technology aspects related to the devices. N = 34 experienced HI-users at a median age of 72 years (range 22-84) completed the trial, n = 5 being monaurally, and n = 29 being binaurally fitted. The trial comprises an unblinded comparative study of the R-HI and T-HI, in either C-mode or L-mode amplification, and a double-blind crossover study evaluating the C-mode versus the L-mode amplification. The results of the unblinded study showed that 94% (n = 32/34) preferred the T-HI, whereas two subjects preferred their current HI. The double-blind crossover study concerning the preference for the C-mode and L-mode, respectively, in the T-HI, showed that 72% (n = 23/32) had a significant preference for the non-linear amplification, whereas 28% (n = 9/32) preferred the linear amplification. Provided that the price of the T-HI is kept unchanged, a health technology evaluation may imply an estimate of 30 mill. DKR added costs on a national basis, which should be taken into account within the national hearing services.

Prevalence of hereditary hearing impairment in adults

This contribution, part of an EU-Concerted Action on the genetics of hearing impairment (H.E.A.R.), describes the preliminary estimated prevalence of hereditary hearing impairment based on retrospective data from a clinical series. Of 27,692 subjects examined in the period 1987-91, we sampled 1265 suffering from unilateral or bilateral hereditary hearing impairment, which is roughly 5% of those examined (n = 384 (31%) male; n = 881 (69%) female). Median age of the subjects is 70 years (range 22-98). Subdividing them into 10-year birth cohorts and applying the local annual population statistics, the prevalence of an overall age-related hereditary hearing impairment was roughly estimated to be 3.2/1000, reflecting prevalences as a function of age from 0.8 to 9.4/1000--prevalence in females being significantly more than in males (4.1/1000 and 2.1/1000, respectively). Overall, a moderate hearing impairment of median 51 dB in the better hearing ear was found, averaged across 0.5-4 kHz, this being fairly constant up to the age of 60, when a significant reduction in hearing sensitivity developed. No significant differences are present as a function of gender, except for the birth cohorts 1910-19 and 1920-29. The most frequent type of hereditary hearing impairment in this sample is otosclerosis, comprising 2% of the total clinical series with a rough population prevalence estimate of 1.4/1000. It is concluded that the established database may be of importance in the aggregation of very rare diseases, and for providing the inspiration for future prospective population studies, resulting in knowledge on the epidemiology of hereditary hearing impairment in adults.

Some Experiences with Hearing Disability/ Handicap and Quality of Life Measures: Algunas experiencias con discapacidad/desventaja auditiva y medidas de calidad de vida

To achieve detailed information on the outcome of hearing rehabilitation in a clinical setting, measurements of hearing disability and hearing handicap have been introduced, and the present study describes the preliminary experiences with these measures in a series of hearing-impaired subjects referred for audiological evaluation. To outline hearing disability/hearing handicap (HD/HH), before continuation or initiation of treatment, the Gothenburg profile and a generic health-related quality of life—the SF-36 questionnaire–were used to evaluate any adverse effects resulting from hearing disorders. The Gothenburg profile and the SF-36 questionnaire were mailed to 634 subjects appointed for audiological examination with a request to complete the questionnaires at home. Three questions were enclosed concerning the capacity to complete the questionnaires, showing that 1.9 per cent were incapable of completing them, 17.5 per cent needed assistance, 43.5 per cent completed the questionnaires, and 37.1 per cent did not respond to them. Thus the response rate was only 55.5 per cent and, in addition, these responses were characterised by missing data. An arbitrary criterion of an average score per question of 3 for the averaged HD and HH items respectively was applied, resulting in 72.7 per cent indicating HD, whereas 30.3 per cent indicated HH according to the items in the profile. Significant differences in hearing levels were found between those experiencing HD and HH having a score 3 and those with a score <3. When analysing the general health status, general perception of health and social functioning, significantly lower scores were found for those experiencing HD/HH, whereas no significant differences were found between the total sample of hearing-impaired subjects and the age-matched population for these parameters. It is concluded that the present procedure cannot be implemented as a routine outcome measure in a clinical setting and alternative outcome measures should be considered. Para obtener información detallada sobre los resultados de la rehabilitation en un contexto clínico, se introdujeron medidas clínicas sobre discapacidad y desventaja auditiva (hearing disability/handicap) y el presente estudio describe las experiencias preliminares con estas medidas, en una serie de sujetos con hipoacusia que fueron referidos para evaluación audiológica. Para subrayar la discapacidad/desventaja auditiva (HD/ HH), antes del inicio o continuatión del trata-miento y para evaluar cualquier efecto adverso resultante de los trastornos auditivos, se utilizaron el perfil Gothenburg y el cuestionario genérico de calidad de vida relacionada con la salud (SF-36). El perfil Gothenburg y el cuestionario SF-36 fueron enviados por correo a 634 sujetos citados para examen audiológico, con la solicitud de que llenaran los cuestionarios en casa. Se incluyeron tres preguntas relacionadas con la capacidad de completar los cuestionarios, mostrando que el 1.9 por ciento eran incapaces de completarlos, que el 17.5 por ciento necesitaron ayuda, que el 43.5 por ciento completaron el cuestionario y 37.1 por ciento no respondieron del todo. Por tanto, la tasa de respuesta fue sólo del 55 por ciento y, además, estas respuestas estuvieron caracterizadas por información incompleta. Se aplico un criterio arbitrario de 3 sobre el puntaje promedio por pregunta, para los items HD y HH promediados, resultando en un 52.3 por ciento que indieaba HD, mientras que un 30.3 por ciento indieo HH, de acuerdo los elementos en el perfil. Se encon-traron diferencias significativas en los niveles auditivos de aquellos sujetos que experimentaban HD y HH con puntaje de 3, en relation con aquellos que tenian puntaje de <3. Cuando se analizó el estado general de salud, la perception de la salud y el funcionamiento social, se encon-traron punlajes significativamente menores en aquellos que experimentaban HD/HH, mientras que no se encontraron diferencias significativas en la muestra total de sujetos hipoacúsicos y la población ordenada por edad pará estos para-metros. Se concluye que el presente procedimiento no puede ser implementado para medidas de resultados rutìnarios en un contexto clínico y que se deben considerar medidas alternativas de resultados.

Evaluation of a hearing screener

The objectives of the present study were to evaluate the compatibility of the hearing screener with pure tone audiometry and its capacity to predict the need and benefit of HAs. The device is a low-cost, easy to handle and safe instrument. It screens at 1 and 3 kHz at three different intensity levels. The outcome of the screen is categorized into six groups according to the number of tones heard and related to eventual fitting of HAs. One hundred and fifty persons (300 ears), with a median age of 65 years (range 20–86 years), consented to a hearing screen prior to pure tone audiometry, which was performed as part of the routine evaluation in the department. A comparative analysis of the pure tone audiometric thresholds and the screen thresholds showed that 27% of ears deviated >10 dB and 4%> 20dB at 1 kHz. At 3 kHz a deviation of >10dB was found in 34% and >20dB in 18%. The screen sensitivity was 92% related to persons and 89% related to ears, whereas the screen specificity was 65% and 62%, respectively. A PPV of 87% was indicated. The benefit of HAs was assured by the IOI-HA and SADL total scores of 3.9 and 4.0, respectively, with significant differences in the scores of the IOI-HA between the screened true and false positives. It is concluded that the screener has potential for use in developing countries and can be used as an alternative lean service delivery in developed countries.