Medires Publishers - Article Full Text

Abstract

Introduction: The consequences of untreated hearing loss in adults can be severe, affecting both their quality of life and economic well-being. Hearing screening for adults may help prevent such impairments in life. The newborn hearing screening demonstrates the efficacy of systematic preventive hearing screening, with impressive success in the countries where it was implemented. The aim of this study was to determine if hearing screening based on auditory brainstem responses (ABR) for adults can be implemented.

Methods: 100 adults (age = 60 – 89 years) underwent ABR-based screening and pure-tone audiometry (PTA). Subjectively perceived hearing impairment was assessed using the Hearing Handicap Inventory for the Elderly Screening Version (HHIE-S) questionnaire.

Results: A screening level of 65 dB for ABR-based screening achieved the highest values for specificity (81.4%) and sensitivity (88.9%). Cases of hearing loss identified through screening were validated by corresponding PTA data (36% with significant hearing loss). The questionnaire identified subjectively perceived hearing impairment in 58% of the participants.

Conclusion: ABR-based hearing screening at 65 dB is a realistic and efficient method to identify adults with significant hearing loss and guide them towards hearing rehabilitation. The test should now be evaluated for suitability for daily use by general practitioners.

Introduction

Hearing loss is a critical health risk factor that affects nearly 20% of the global population [1]. There is a wide range of causes of hearing loss and a wide range of individuals affected, spanning from newborns to elderly, with an estimated 65% of those aged over 60 years experiencing significant hearing loss. In older adults, this can have severe implications for overall health: Starting with decreased occupational performance followed by a negative impact on their economic potential, hearing loss may lead to social withdrawal [2], a severe reduction of quality of life, and even increased potential dementia progression [3-6]. Early measures for appropriate hearing rehabilitation can prevent further deprivation of auditory processing and, thus, significantly mitigate these negative effects of hearing loss [7,8]. This, however, requires timely identification of affected individuals.

A positive example of the early detection and management of hearing loss is the newborn hearing screening (NHS), which has globally contributed to significant improvements in the hearing development of children with hearing loss. In Germany, for instance, most newborns are screened for potential hearing loss within the first week of life. In the case of a negative result, they undergo further diagnostic evaluation and, if necessary, hearing rehabilitation.

Automated auditory brainstem response (ABR) testing has proven particularly effective in such screenings, as it can be conducted reliably within a few minutes. Its simplified result classification into “pass” and “fail” provides a clear indication of whether further diagnostic steps are needed [9].

The increasingly evident risk of hearing loss in older adults has led to numerous initiatives to detect hearing loss as early as possible using simple methods [10-20]. Therefore, the present study aimed to investigate the feasibility of introducing hearing screening for older adults, specifically individuals over 60 years of age.

For this purpose, it is first required to determine an appropriate stimulus level for the screening, hereinafter referred to as “screening level”. Due to the physiological decline in hearing with age, the screening level needs to be considerably higher than the standard screening level of 35 dBHL used in newborns. The primary aim of this study was to determine the screening level at which the screening results show high specificity and sensitivity.

Methods

Inclusion Criteria

Eligible participants were individuals > 60 years based on the definition of older adults by the United Nations, who were free of infections of the upper respiratory tract [21]. Pre-existing diseases and hearing loss were not considered to be exclusion criteria.

Ethics

This prospective study was approved by the local ethics committee of the university clinic of Wuerzburg (74/24) and conducted in accordance with the Declaration of Helsinki, and Parts I and II of ISO 14155 (2021) regarding the conduct of clinical investigations involving human subjects.

Measurement Methodology

The test procedure was divided into three segments.

First, the specialized Hearing Handicap Inventory for Elderly Screening questionnaire (HHIE- S) was used for subjective initial assessment of the participants’ hearing ability [18]. This questionnaire contains 10 questions about hearing ability, aiming to identify hearing problems in daily life. For example, it asks about conversations with family members and difficulties watching television or listening to the radio. Each “yes” response is awarded four points, which are then summarized to produce a total score. The higher the total score, the greater the handicap caused by the hearing loss. Scores can range from 0 (no handicap) to 40 (maximum handicap). Audiological evaluation is recommended for scores of 10 points or higher. The HHIE-S questionnaire was used in German.

Second, the hearing screening was performed. The device easy Screen (Maico, Berlin, Deutschland, figure 6) was used. This device has already been proven to be effective in NHS [9]. It allows for automated binaural ABR testing at a pre-set screening level. Auditory evoked potentials (AEP) are recorded simultaneously on both sides between the center of the apex and the mastoid. The integrated CE-Chirp is used as acoustic stimulus, delivered via in-ear headphones at a stimulus rate of approximately 90/s. The EEG is analyzed automatically during the test. Once an AEP is detected, the test is terminated with a “pass” result. If no AEP is detected within 3 minutes, the test concludes with the result “fail”, indicating further evaluation is necessary. The screening results are reported separately for the left and right ear. For this study, the devices’ manufacturer enabled the option to select various stimulus levels for the screening, ranging from 35 dBHL to 70 dBHL in 5 dB increments. This allowed the hearing thresholds of the participants to be determined with a precision of up to 5 dB using the screening device.

Figure6: Screening device EasyScreen® (MAICO diagnostics, Berlin)

Third, the participants’ PTA was determined to assess the subjective hearing threshold. Pure tones in the frequency range of 0.25 kHz to 8 kHz were presented via headphones (TDh39, Telephonics, USA) and bone conduction transducers (B71, RadioEar, USA) at varying sound levels until the hearing threshold was established through participant input. The obtained complete audiogram with air and bone conduction thresholds can be interpreted based on the curve’s pattern. Physiological patterns, presbycusis, conductive hearing loss (e.g., middle ear effusion, otitis media), or noise-induced trauma (e.g., a C5 notch at 4 kHz) can be clearly identified.

In this study, two key values were determined: (1) specificity: the number of normally hearing participants falsely identified as having hearing loss during the screening, and (2) sensitivity: the number of participants with suspected treatment-requiring hearing loss correctly identified as having hearing loss during the screening. The calculation of specificity and sensitivity is primarily based on the PTA3 (Pure Tone Average at 1k, 2k, and 4 kHz) thresholds [22]. Participants who exceeded a predefined PTA3Ref- threshold or were already fitted with hearing aids were classified as individuals with abnormal hearing results. All other participants were considered normal-hearing (Rule 1). Another reference value concerned the screening hearing threshold (ScPGRef). If participants did not pass this level during the screening, they were classified as individuals with abnormal hearing results; otherwise, they were considered normal-hearing (Rule 2). Specificity was then calculated by the number of participants classified as individuals with abnormal hearing screening results (Rule 2) divided by the number of normal-hearing participants based on PTA3 (Rule 1). Sensitivity was calculated by the number of participants classified as individuals with abnormal hearing screening results (Rule 2) divided by the number of individuals with abnormal PTA3 results (Rule 1).

Statistical Analysis

R for Windows 3.5.3 (R Core Team, USA) was used for statistical data analysis. Descriptive statistics were used to analyze age, hearing thresholds, and screening level data. Correlation analysis was conducted between PTA3 thresholds, the screening hearing thresholds, and the questionnaire results. The significance level was set at 5%.

Results

Study Participants

100 participants were included in the study. Participants were between 60 and 89 years old (mean 69.3 years). Figure 1 illustrates the age distribution of the participants.

Measurement Outcomes

All participants completed the questionnaire; screening was successfully performed in all participants; audiograms were obtained in all participants:

The correlation analysis between PTA3 thresholds and screening hearing thresholds showed a strong correlation of rp = 0.65 (p < 0.01).

The average hearing screening threshold was 52.5 dBHL. This threshold was far too low as a reference value (39% specificity) to achieve sensitivity of close to 100%. To determine the optimal screening level, various combinations of reference values for screening levels and PTA3 thresholds were analyzed. Table 1 presents the screening and PTA3 reference levels that were most promising in terms of specificity and sensitivity for reliable screening results. The optimum was achieved with a screening reference level (ScRef) of 65 dBHL and a PTA3 reference threshold (PTA3Ref) of 45 dBHL. This combination achieved a specificity of 81.4% and a sensitivity of 88.9%.

Figure1: Age distribution of the participants.

Table1: Specificity and sensitivity for different screening levels and PTA3 values.

Figure 2 shows the average audiograms of both groups normal-hearing (n = 59) and individuals with abnormal hearing results (n = 36) for an optimal combination of ScPGRef and PTA3R

Figure2: Averaged audiograms of the groups individuals with abnormal hearing results and normal-hearing.

Correlation analysis showed a significant correlation between screening thresholds and PTA3 (rp = 0.65 (p < 0.01) (Figure 3).

Figure3: Correlation between PTA3 and screening hearing thresholds.

Figure 4 shows the comparison of HHIE-S scores to screening and audiological results. The questionnaire evaluation revealed a moderate handicap in 49%; a severe handicap in 9%; and no handicap in 42% of the participants.

Figure4: Distribution of HHIE-S scores into handicap scores.

Correlation analysis showed a weak correlation between the HHIE-S score and PTA3 (rp = 0.48 (p < 0.01)) (Figure 5).

Figure5: Correlation between PTA3 and HHIE-S scores.

Discussion

As outlined previously, the World Report on Hearing [23] revealed an alarmingly high number of individuals worldwide affected by severe hearing loss (approximately 20% of the global population). Among individuals over the age of 60, the estimated prevalence is 65%. Due to the associated reductions in individual quality of life and economic loss caused by reduced productivity and the costs linked to severe hearing loss, the report strongly recommended global hearing screening.

Over the past two decades, the topic of hearing screening in adults has increasingly gained attention from various medical and social research groups, aiming to mitigate the resulting harm to those affected as well as the general public [2,4,5,6,12,24]. Preventive measures can help avoid the damage caused by undetected or untreated hearing loss [8]. However, this requires an effective hearing screening program for adults, followed by timely hearing rehabilitation. Establishing a universal hearing screening program for adults is a significant challenge that will not be easy to overcome. Various approaches have been tested with varying levels of complexity and success. Economic analyses have also been conducted to evaluate costs and potential savings [25-27]. While a PTA would be the standard ideally, implementing this on a large scale is not feasible. Self-assessment using questionnaires, as was done in this study, appears to be a more practical option. The outcomes of hearing-specific questionnaire screenings vary widely but some authors report reliable identification of individuals with hearing loss [19,20,28-30]. The widespread use of smartphones and tablets could also help facilitate hearing screening. Several apps and programs already exist, although their effectiveness – particularly for older adults – remains debated [10,16,19,31-33]. Other methods include screenings with portable devices, whisper tests, and speech-in-noise tests. The feasibility and success of these approaches still require further evaluation [14,33,34].

The implementation and success of adult hearing screening programs must measure up to the global success of NHS. After years of organizational and technical development, NHS has become the gold standard, offering rapid and reliable testing just days after birth [9,35-38]. Applying similar techniques for adult hearing screening appears promising.

The goal of this study was to determine an appropriate screening level for screening in older adults. The results showed that the PTA3 (the average hearing thresholds at 1 kHz, 2 kHz, and 4 kHz) is the most suitable measure. It is well-known that high-frequency hearing loss is particularly prevalent in older age [3]. The correlation between PTA3 thresholds and screening thresholds was quite strong at rp = 0.65. To determine the screening level, audiograms of participants were analyzed to classify them into normal-hearing and individuals with abnormal hearing results. The average hearing screening threshold was 52.5 dBHL but it was found that a screening level of 65 dBHL was necessary to achieve adequate specificity (81.4%) and sensitivity (88.9%). This is crucial for success in field tests. In other studies, lower thresholds for specificity and sensitivity were accepted [10,13,16,17,19,29,34]. Compared to NHS, these thresholds are much lower, leading to more false positives (normal-hearing individuals requiring further testing) and fewer detected cases of hearing loss [35]. However, this is less problematic in adults than in children, as language development is already complete and the hearing loss does not impact developmental processes [37]. Despite this, it remains crucial to avoid the severe consequences of hearing loss. Many individuals are unaware of the fact that timely hearing rehabilitation can address many of these issues [39]. There are, however, reports suggesting that even with screening, success rates for hearing rehabilitation remain limited [40].

The questionnaire results in this study revealed that 58% of participants reported problems in daily life due to reduced hearing ability. These results are comparable to a study conducted in the Czech Republic in 2020–2021, which assessed the sensitivity of the HHIE-S questionnaire and correlated the results with audiometric tests [29]. The relatively low correlation between questionnaire scores and both PTA3 and screening thresholds may stem from the subjective nature of participant self-assessments.

Several things must be considered critically when conducting screenings. The absence of proper soundproofing in testing rooms and participant stress can complicate the screening process. During tests, improperly attached electrodes can lead to high impedance, resulting in measurement errors. Poor fitting in-ear headphones (due to small or narrow ear canals) can produce false-negative results. In addition, some participants reported the acoustic stimuli to be unpleasant, describing them as resembling construction site noises. Ensuring a calm environment (preferably in a soundproof room) and providing clear explanations of the test procedure can help minimize participant discomfort and improve measurement reliability. If these measures are established, the testing can generally be conducted without complications, ensuring reproducible results for further analysis.

Following the successful establishment of this simple screening method for adults, it is now necessary to implement the testing procedure under general conditions, such as in medical practices. The aim would be to ensure that patients with screening results that are indicative of hearing loss are referred for further testing by an ENT specialist, a hearing aid professional or similar. Existing literature suggests that integrating adult hearing screening into the workflows of general medical practices is the most promising approach [11,15,41]. Accordingly, a follow-up study will evaluate the reliability of using the ABR-based hearing screening levels determined in this study under these practical conditions.

Conclusion

There is an urgent need for the implementation of adult hearing screening due to the significant impact of late-detected and inadequately managed hearing loss in older adults. Based on the experiences gained from NHS, an ABR-based test appears to be a suitable option. A screening level of 65 dB has proven particularly effective in achieving high specificity and sensitivity. The practical application should now be tested in general medical practices for individuals aged 60 and older to determine whether this approach can lead to an increase in successful hearing rehabilitation in older adults.

Acknowledgements

The authors would like to thank Laura Sturm (MED-EL Innsbruck, Austria) for her language services.

Appendix

Hearing Handicap Inventory for the Elderly Screening Version (HHIE-S)

HHIE-S scoring and interpretation

References

1. WHO. (2022a). The European Health Report 2021. Taking stock of the health-related Sustainable Development Goals in the COVID-19 era with a focus on leaving no one behind. World Health Organization Regional Office for Europe.
   View at Publisher | View at Google Scholar
2. Davis, Adrian, and Pauline Smith. “Adult hearing screening: Health policy issues—What happens next?.” American Journal of Audiology 22, no. 1 (2013): 167-170.
   View at Publisher | View at Google Scholar
3. Diao, Tongxiang, Xin Ma, Junbo Zhang, Maoli Duan, and Lisheng Yu. “The correlation between hearing loss, especially high-frequency hearing loss and cognitive decline among the elderly.” Frontiers in Neuroscience 15 (2021): 750874.
   View at Publisher | View at Google Scholar
4. Laplante-Lévesque, Ariane, K. Jonas Brännström, Elisabeth Ingo, Gerhard Andersson, and Thomas Lunner. “Stages of change in adults who have failed an online hearing screening.” Ear and Hearing 36, no. 1 (2015): 92-101.
   View at Publisher | View at Google Scholar
5. Löhler, Jan, Mario Cebulla, Wafaa Shehata-Dieler, Stefan Volkenstein, Christiane Völter, and Leif Erik Walther. “Schwerhörigkeit im Alter–Erkennung, Behandlung und assoziierte Risiken.” Dtsch Arztebl Int 116, no. 17 (2019): 301-310.
   View at Publisher | View at Google Scholar
6. Mick, Paul, and M. Kathleen Pichora-Fuller. “Is hearing loss associated with poorer health in older adults who might benefit from hearing screening?.” Ear and hearing 37, no. 3 (2016): e194-e201.
   View at Publisher | View at Google Scholar
7. Grandori, Ferdinando, and Alessia Paglialonga. “Introduction to the AJA research forum on hearing screening in adults and older adults.” History 22, no. 1 (2013): 165-166.
   View at Publisher | View at Google Scholar
8. Linssen, A. M., M. A. Joore, E. J. J. M. Theunissen, and L. J. C. Anteunis. “The effects and costs of a hearing screening and rehabilitation program in residential care homes for the elderly in the Netherlands1.” American Journal of Audiology 22, no. 1 (2013): 186-189.
   View at Publisher | View at Google Scholar
9. Cebulla, Mario, and Wafaa Shehata-Dieler. “ABR-based newborn hearing screening with MB11 BERAphone® using an optimized chirp for acoustical stimulation.” International Journal of Pediatric Otorhinolaryngology 76, no. 4 (2012): 536-543.
   View at Publisher | View at Google Scholar
10. Balen, Sheila Andreoli, Bianca Stephany Barbosa Vital, Rhadimylla Nágila Pereira, Taise Ferreira de Lima, Daniele Montenegro da Silva Barros, Esteban Alejandro Lopez, Jose Diniz Junior, Ricardo Alexsandro de Medeiros Valentim, and Deborah Viviane Ferrari. “Accuracy of affordable instruments for hearing screening in adults and the elderly.” In CoDAS, vol. 33, p. e20200100. Sociedade Brasileira de Fonoaudiologia, 2021.
    View at Publisher | View at Google Scholar
11. Bettger, Janet Prvu, Rowena J. Dolor, David L. Witsell, Judy R. Dubno, Carl F. Pieper, Amy R. Walker, Mina Silberberg et al. “Comparative implementation-effectiveness of three strategies to perform hearing screening among older adults in primary care clinics: study design and protocol.” BMC geriatrics 20, no. 1 (2020): 170.
    View at Publisher | View at Google Scholar
12. Chadha, Shelly, Lauren K. Dillard, Silvio P. Mariotti, and Stuart Keel. “Monitoring hearing and vision functions in older adults: rationale and process.” Age and ageing 52, no. Supplement_4 (2023): iv158-iv161.
    View at Publisher | View at Google Scholar
13. Chayaopas, Nichtima, Pornthep Kasemsiri, Panida Thanawirattananit, Patorn Piromchai, and Kwanchanok Yimtae. “The effective screening tools for detecting hearing loss in elderly population: HHIE-ST Versus TSQ.” BMC geriatrics 21, no. 1 (2021): 37.
    View at Publisher | View at Google Scholar
14. Di Berardino, Federica, Ivan Cortinovis, Anna Gasbarre, Eliana Filipponi, Silvano Milani, and Diego Zanetti. “Verbal task and motor responses (VTMR) in an adult hearing screening programme.” ACTA Otorhinolaryngologica Italica 40, no. 1 (2019): 57.
    View at Publisher | View at Google Scholar
15. Höbler, Fiona, Katherine S. McGilton, Walter Wittich, Kate Dupuis, Marilyn Reed, Shirley Dumassais, Paul Mick, and M. Kathleen Pichora-Fuller. “Hearing screening for residents in long-term care homes who live with dementia: a scoping review.” Journal of Alzheimer’s Disease 84, no. 3 (2021): 1115-1138.
    View at Publisher | View at Google Scholar
16. Kam, Anna Chi Shan, and Christine Hiu Tung Fu. “Screening for hearing loss in the Hong Kong Cantonese-speaking elderly using tablet-based pure-tone and word-in-noise test.” International journal of audiology 59, no. 4 (2020): 301-309.
    View at Publisher | View at Google Scholar
17. Ting, Hsin-Chen, and Yung-Yao Huang. “Sensitivity and specificity of hearing tests for screening hearing loss in older adults.” Journal of Otology 18, no. 1 (2023): 1-6.
    View at Publisher | View at Google Scholar
18. Ventry, Ira M., and Beth E. Weinstein. “Identification of elderly people with hearing problems.” Asha 25, no. 7 (1983): 37-42.
    View at Publisher | View at Google Scholar
19. Wang, Kairong, Wanrui Wei, Jiyuan Shi, Beier Qi, Zheng Zhu, and Zheng Li. “Diagnostic accuracy of mobile health-based audiometry for the screening of hearing loss in adults: a systematic review and meta-analysis.” Telemedicine and e-Health 29, no. 10 (2023): 1433-1445.
    View at Publisher | View at Google Scholar
20. You, Sunghwa, Woojae Han, Saea Kim, Sanga Maeng, and Young Joon Seo. “Reliability and validity of self-screening tool for hearing loss in older adults.” Clinical interventions in aging (2020): 75-82.
    View at Publisher | View at Google Scholar
21. United Nations. (2019). World Population Ageing 2019. Department of International Economic.
    View at Publisher | View at Google Scholar
22. Michel, O. “DIN EN ISO 7029: 2017-06.” HNO 69, no. 12 (2021): 1014-1018.
    View at Publisher | View at Google Scholar
23. WHO. (2022b). World Report on Hearing. World Health Organization.
    View at Publisher | View at Google Scholar
24. Paglialonga, Alessia, and Ferdinando Grandori. “Introduction to the AJA research forum on intervention and rehabilitation strategies for adults and older adults.” American Journal of Audiology 22, no. 2 (2013): 321-322.
    View at Publisher | View at Google Scholar
25. Borre, Ethan D., Judy R. Dubno, Evan R. Myers, Susan D. Emmett, Juliessa M. Pavon, Howard W. Francis, Osondu Ogbuoji, and Gillian D. Sanders Schmidler. “Model-projected cost-effectiveness of adult hearing screening in the USA.” Journal of General Internal Medicine 38, no. 4 (2023): 978-985.
    View at Publisher | View at Google Scholar
26. Linssen, Anouk M., Lucien JC Anteunis, and Manuela A. Joore. “The cost-effectiveness of different hearing screening strategies for 50-to 70-year-old adults: a Markov model.” Value in Health 18, no. 5 (2015): 560-569.
    View at Publisher | View at Google Scholar
27. Ye, Xin, and Ping He. “Economic Burden of Hearing Loss inMiddle-Aged and Older Adults in China.” Journal of Applied Gerontology 42, no. 1 (2023): 76-88.
    View at Publisher | View at Google Scholar
28. Kim, Gibbeum, Wondo Na, Gungu Kim, Woojae Han, and Jinsook Kim. “The development and standardization of self-assessment for hearing screening of the elderly.” Clinical Interventions in Aging (2016): 787-795.
    View at Publisher | View at Google Scholar
29. Kovalová, Martina, Eva Mrázková, Michaela Škerková, Zdeněk Čada, and Jana Janoutová. “Przydatność badań przesiewowych w wykrywaniu niedosłuchu u osób starszych.” Otolaryngologia Polska 76, no. 3 (2021): 32-38.
    View at Publisher | View at Google Scholar
30. Rothpletz, Ann M., Ashley N. Moore, and Jill E. Preminger. “Acceptance of internet-based hearing healthcare among adults who fail a hearing screening.” International Journal of Audiology 55, no. 9 (2016): 483-490.
    View at Publisher | View at Google Scholar
31. Livshitz, Leonid, Reem Ghanayim, Carmi Kraus, Raymond Farah, Ella Even-Tov, Yaniv Avraham, Adi Sharabi-Nov, and Peter Gilbey. “Application-based hearing screening in the elderly population.” Annals of Otology, Rhinology & Laryngology 126, no. 1 (2017): 36-41.
    View at Publisher | View at Google Scholar
32. Stenfelt, Stefan, Thomas Janssen, Volker Schirkonyer, and Ferdinando Grandori. “e-Health technologies for adult hearing screening.” Audiology Research 1, no. 1 (2011): e14.
    View at Publisher | View at Google Scholar
33. Vercammen, Charlotte, Tine Goossens, Jan Wouters, and Astrid Van Wieringen. “Digit triplet test hearing screening with broadband and low-pass filtered noise in a middle-aged population.” Ear and hearing 39, no. 4 (2018): 825-828.
    View at Publisher | View at Google Scholar
34. Cardoso, Carolina Louise, Ângelo José Gonçalves Bós, Andréa Krüger Gonçalves, Maira Rozenfeld Olchik, Leticia Sousa Flores, Bruna Macagnin Seimetz, Magda Aline Bauer, Patricia Pérez Coradini, and Adriane Ribeiro Teixeira. “Sensitivity and specificity of portable hearing screening in middle-aged and older adults.” International archives of otorhinolaryngology 18, no. 01 (2014): 021-026.
    View at Publisher | View at Google Scholar
35. Hofmann, S. B. (2012). Sensitivitätsstudie zum Neugeborenen-Hörscreening mit dem BERAphon®.
    View at Publisher | View at Google Scholar
36. Kanji, Amisha, Katijah Khoza-Shangase, and Nomfundo Moroe. “Newborn hearing screening protocols and their outcomes: A systematic review.” International journal of pediatric otorhinolaryngology 115 (2018): 104-109.
    View at Publisher | View at Google Scholar
37. Kral, Katrin. “Frühkindliche Entwicklung bei Kindern mit einer Hörschädigung im Vergleich zu hörenden Kindern. Kognition, Sprache, Motorik.” PhD diss., Universität zu Köln, 2016.
    View at Publisher | View at Google Scholar
38. Morton, Cynthia C., and Walter E. Nance. “Newborn hearing screening—a silent revolution.” New England Journal of Medicine 354, no. 20 (2006): 2151-2164.
    View at Publisher | View at Google Scholar
39. Pronk, Marieke, Sophia E. Kramer, Adrian C. Davis, Dafydd Stephens, Pauline A. Smith, Chryssoula Thodi, Lucien JC Anteunis, Marta Parazzini, and Ferdinando Grandori. “Interventions following hearing screening in adults: A systematic descriptive review.” International Journal of Audiology 50, no. 9 (2011): 594-609.
    View at Publisher | View at Google Scholar
40. Thodi, Chryssola, Marta Parazzini, Sophia E. Kramer, Adrian Davis, Stefan Stenfelt, Thomas Janssen, Pauline Smith et al. “Adult hearing screening: follow-up and outcomes1.” American journal of audiology 22, no. 1 (2013): 183-185.
    View at Publisher | View at Google Scholar
41. Ramdoo, Krishan, Jordan Bowen, Oliver T. Dale, Rogan Corbridge, Apurba Chatterjee, and Margot A. Gosney. “Opportunistic hearing screening in elderly inpatients.” SAGE open medicine 2 (2014): 2050312114528171.
    View at Publisher | View at Google Scholar