Establishing critical differences in ear-canal stimulus amplitude for detecting middle ear muscle reflex activation during olivocochlear efferent measurements.

Objective: Assessments of the medial olivocochlear reflex (MOCR) may have clinical utility. The MOCR is measured using contralateral inhibition of otoacoustic emissions but concurrent activation of the middle ear muscle reflex (MEMR) confounds test interpretation. MEMR activation can be detected using the change in ear-canal stimulus amplitude without versus with an MOCR elicitor. This study provides a description of how critical differences in ear-canal stimulus amplitude can be established.Design: Clicks were presented in right ears without and with a contralateral MOCR elicitor. Ear-canal stimulus amplitudes were measured. Two measurements without an elicitor were used to develop critical differences. MEMR activation was considered present if the difference in ear-canal stimulus amplitude without versus with an elicitor exceeded the critical difference.Study sample: Forty-six normal-hearing adults (mean age = 23.4 years, 35 females) participated, with data from 44 participants included in the final analysis.Results: Two participants exceeded the 95% critical difference. The 80, 90 and 99% critical differences are also reported for reference.Conclusions: Results suggest that the contralateral elicitor can evoke the MEMR in a small number of participants. The methods described in this paper can be used for developing equipment- and clinic-specific critical differences for detecting MEMR activation.

Follow-up on the diagnostic level of children covered by the Universal Neonatal Hearing Screening Program in Poland, divided into voivodships.

INTRODUCTION: Thanks to the Polish Universal Neonatal Hearing Screening Program (PUNHSP), all newborns in Poland undergo a free, screening hearing examination. Between 2006 and 2015, the average number of tested children per year was 373,477. According to the analysis of The Central Database (CDB), only 55.8% of the children attended the detailed hearing examinations at the second level of the Program. AIM: The aim of this study is to analyse the dates concerning the attendance of the children at the diagnostic level of PUNHSP in different regions of Poland. MATERIALS AND METHODS: To conduct an analysis of this fact and find out the reasons for low attendance at the second level in 2015, a telephone survey questionnaire was developed for parents who had not registered their babies for further consultation - 3,239 randomly selected parents. RESULTS: The analysis revealed that the number of children examined at the second diagnostic level of the program is in fact much higher than the results of The Central Database show. The actual number is 83.6% as opposed to 55.8%. As a result of the telephone questionnaire some inaccuracies in the input data to the CDB were detected. The main errors in gathering the information for the CDB were incorrect OAE test result and no examination performed. C onclusion: In Poland the worst results (i.e. questionnaire results compared to CDB) for the attendance at the diagnostic level were shown in Pomorskie, Lubelskie, Mazowieckie and Podlaskie regions. In many cases there was a large discrepancy between the reality and the information in the CDB. The improvement of clarity concerning the CDB application is important in order to minimise the possibility of malformation in the CDB.

Objective methods to measure vestibular evoked myogenic potential response saccular tuning curves.

Objective: To detect cervical vestibular evoked myogenic potential (cVEMP) responses using objective statistical approaches and to apply this approach to estimate saccular frequency-tuning curves in volunteers and Ménière's disease (MD) patients. Design: Estimates of cVEMP threshold were carried out by 3 expert raters at 500 Hz and compared to objective threshold estimates (using Hotelling's T2 [HT2] and Fsp). Saccular tuning curves were objectively estimated. Study sample: Objective and subjective estimates of cVEMP response thresholds were compared for 13 normal hearing adults. Objective measurement of saccular tuning curves was explored in 20 healthy adults and 15 patients with MD. Results: Significant variability was seen between subjective estimates of cVEMP thresholds. Objective analysis with the HT2 test was more sensitive than 2 of 3 experts in detecting responses. The measurement time of cVEMP was considerably reduced with the HT2 test. Objective saccular tuning curves in volunteers showed strongest responses at 500 Hz. A flatter tuning curve was seen for MD patients. Conclusions: There is significant variability in subjective estimations of cVEMP thresholds. Objective analysis methods are more sensitive than subjective analysis, can detect responses rapidly and have potential to reduce variability in threshold estimates, hence they appear well suited to measure cVEMP tuning curves.

Evaluation of Childhood Vaccine Refusal and Hesitancy Intentions in Turkey.

OBJECTIVE: To assess the factors affecting parental childhood vaccine refusal and hesitancy (CVRH) intentions in Turkey. METHODS: A total of 33 children's parents who were referred to two different child health care clinics because of CVRH and 99 controls were enrolled into this study from November through December 2017. The socio-demographic characteristics and perceptions of the parents who refused at least one vaccine for their child/children were compared with controls. RESULTS: The monthly household income was significantly lower in CVRH group than control group. Refusal of the heel stick, refusal of hearing test, not using baby car seat, irregular use of vitamin D and iron prophylaxis, using alterative/complementary medicine, distrust in vaccines were the parameters which were found significantly higher in refused vaccine group than in control group. The beliefs "It may be dangerous for children" and "Distrust to the vaccines" were the most determined factors with a ratio of 51.5% in CVRH group. CONCLUSIONS: This is the first study conducted to investigate the social-demographic characteristics and perception of parental CVRH in Turkey. The beliefs "It may be dangerous for the children" and "Distrust the vaccines" were the most determined factors which may affect CVRH. Some child health protective strategies were less undertaken in CVRH group than in controls; including heel stick test, hearing test, using baby car seat and using of Vitamin D and iron prophylaxis. The parents who have CVRH intentions tend to behave irresponsibly in care of their children.

Unbound bilirubin measurements by a novel probe in preterm infants.

BACKGROUND: Hyperbilirubinemia occurs in over 80% of newborns and severe bilirubin toxicity can lead to neurological dysfunction and death, especially in preterm infants. Currently, the risk of bilirubin toxicity is assessed by measuring the levels of total serum bilirubin (TSB), which are used to direct treatments including immunoglobulin administration, phototherapy, and exchange transfusion. However, free, unbound bilirubin levels (Bf) predict the risk of bilirubin neurotoxicity more accurately than TSB. OBJECTIVE: To examine Bf levels in preterm infants and determine the frequency with which they exceed reported neurotoxic thresholds. METHODS: One hundred thirty preterm infants (BW 500-2000 g; GA 23-34 weeks) were enrolled and Bf levels measured during the first week of life by the fluorescent Bf sensor BL22P1B11-Rh. TSB and plasma albumin were measured by standard techniques. Bilirubin-albumin dissociation constants (Kd) were calculated based on Bf and plasma albumin. RESULTS: Five hundred eighty samples were measured during the first week of life, with an overall mean Bf of 13.6 ± 9.0 nM. A substantial number of measurements exceeded potential toxic thresholds levels as reported in the literature. The correlation between Bf and TSB was statistically significant (r2 0.17), but this weak relationship was lost at high Bf levels. Infants <28-week gestations had more hearing screening failures than infants ≥28-week gestation. CONCLUSIONS: Unbound (free) bilirubin values are extremely variable during the first week of life in preterm infants. A significant proportion of these values exceeded reported neurotoxic thresholds.

Data-Driven Approach for Auditory Profiling and Characterization of Individual Hearing Loss.

Pure-tone audiometry still represents the main measure to characterize individual hearing loss and the basis for hearing-aid fitting. However, the perceptual consequences of hearing loss are typically associated not only with a loss of sensitivity but also with a loss of clarity that is not captured by the audiogram. A detailed characterization of a hearing loss may be complex and needs to be simplified to efficiently explore the specific compensation needs of the individual listener. Here, it is hypothesized that any listener's hearing profile can be characterized along two dimensions of distortion: Type I and Type II. While Type I can be linked to factors affecting audibility, Type II reflects non-audibility-related distortions. To test this hypothesis, the individual performance data from two previous studies were reanalyzed using an unsupervised-learning technique to identify extreme patterns in the data, thus forming the basis for different auditory profiles. Next, a decision tree was determined to classify the listeners into one of the profiles. The analysis provides evidence for the existence of four profiles in the data. The most significant predictors for profile identification were related to binaural processing, auditory nonlinearity, and speech-in-noise perception. This approach could be valuable for analyzing other data sets to select the most relevant tests for auditory profiling and propose more efficient hearing-deficit compensation strategies.

Hearing tests are just child's play: the sound scouts game for children entering school.

OBJECTIVE: To create a hearing test useable without the involvement of a clinician or calibrated equipment, suitable for children aged 5 or older. DESIGN: The tablet-based app (Sound Scouts) includes tests of speech in quiet, speech in noise and tones in noise, all embedded in game designed to maintain attention. Data were collected to intelligibility-equalize the stimuli, establish normative performance, and evaluate the sensitivity with which Sound Scouts detected known hearing problems and identified their type. STUDY SAMPLE: Participants were children from age 5 to 14 (394 with normal hearing, 97 with previously identified hearing loss) and 50 adults with normal hearing. RESULTS: With pass-fail criteria set such that 98% of children with normal hearing passed Sound Scouts, 85% of children with hearing loss failed Sound Scouts (after exclusion of children in either group who received an inconclusive result or had incomplete results). No child with four-frequency average hearing thresholds of 30 dB HL or greater in their poorer ear passed Sound Scouts. Hearing loss type was correctly identified in only two-thirds of those cases where the algorithm attempted to identify a single type of loss. CONCLUSIONS: Sound Scouts has specificity and sensitivity sufficiently high to provide hearing screening around the time children typically enter school.

Hearing screening in newborns in the Central Denmark Region.

INTRODUCTION: In 2005, a nationwide programme on hearing screening in newborns was launched in Denmark. The purpose of the programme was to ensure early detection of hearing loss in newborns and to institute subsequent treatment. The aim of this study was to assess whether the Central Denmark Region observes the guidelines of the Danish Health and Medicines Authority (DHMA) for neonatal hearing. In addition, we wanted to identify factors that may influence screening density positively or negatively. METHODS: Data were collected retrospectively from patient record forms completed in the 2006-2014 period. For selected periods, patient record forms were examined man-ually. RESULTS: We recorded an annual increase in average screening density; from 88.6% in 2006 to 94.8% in 2013. Furthermore, in 2006, 89.5% had completed the hearing screening programme within 30 days and in 2014 this figure had increased to 99%. The average time to diagnosis decreased from 3.5 months in 2006 to 0.7 months in 2013. A strike among healthcare professionals in 2008 and the launch of electronic patient record (EPJ) forms in 2012 had a negative impact on screening density. Due to EPJ errors, the hearing screening density occasionally appeared to be lower than the actual number of newborns screened. In contrast, advanced training of primary screening staff, the establishment of close relations with the primary screening units in hospitals and the implementation of "Maternity packages" improved screening density. CONCLUSION: Based on our results, our conclusion is that the Central Denmark Region observes the DHMA guidelines on neonatal hearing screening in Denmark. FUNDING: none. TRIAL REGISTRATION: not relevant.

[Impact of the Overlap Region Between Acoustic and Electric Stimulation]. / Einfluss des Überlappungsbereichs zwischen akustischer und elektrischer Stimulation.

Patients with residual hearing in the low frequencies and ski-slope hearing loss with partial deafness at medium and high frequencies receive a cochlear implant treatment with electric-acoustic stimulation (EAS, "hybrid" stimulation). In the border region between electric and acoustic stimulation a superposition of the 2 types of stimulation is expected. The area of overlap is determined by the insertion depth of the stimulating electrode and the lower starting point of signal transmission provided by the CI speech processor. The study examined the influence of the variation of the electric-acoustic overlap area on speech perception in noise, whereby the width of the "transmission gap" between the 2 different stimulus modalities was varied by 2 different methods. The results derived from 9 experienced users of the MED-EL Duet 2 speech processor show that the electric-acoustic overlapping area and with it the crossover frequency between the acoustic part and the CI should be adjusted individually. Overall, speech reception thresholds (SRT) showed a wide variation of results in between subjects. Further studies shall investigate whether generalized procedures about the setting of the overlap between electric and acoustic stimulation are reasonable, whereby an increased number of subjects and a longer period of acclimatization prior to the conduction of hearing tests deemed necessary.

[Newborn Hearing Screening - Results of a Parental Survey in Saxony-Anhalt]. / Neugeborenen-Hörscreening ­ Ergebnisse einer Elternbefragung in Sachsen-Anhalt.

Background: In recent years quality assurance has become an essential part of today's health-care system in the wake of the modern patient-oriented quality management. With the statutory introduction of newborn hearing screening (NHS) in 2009, a quality assurance of these early detection methods has become necessary. The aim of the study was to determine patient satisfaction in relation to the NHS in Saxony-Anhalt. Patients/Methods: During the period from November 2013 to April 2014, 394 parents were retrospectively interviewed about their experiences and expectations in relation to the NHS, using a standardised questionnaire. In total, 21 child care centres and 6 paediatric primary care centres from all over Saxony-Anhalt were involved. Results: It turns out that the majority of parents are satisfied with the NHS and 97.7% are in favour of the offer of an NHS. Of the surveyed parents, 69.3% felt the information as sufficient. However, only 66.2% of parents took a closer look at the leaflet issued by the G-BA. In addition, 17.7% of respondents are dissatisfied with the professional competence of the examining staff. Conclusion: The study shows that the general attitude among parents towards newborn hearing screening was very positive. They felt reassured by it although there are some aspects still open to criticism.

Objective assessment of subjective tinnitus through contralateral suppression of otoacoustic emissions by white noise; suggested cut-off points.

OBJECTIVE: Normative otoacoustic emission (OAE) suppression values are currently lacking and the role of cochlear efferent innervation in tinnitus is controversial. The aim of this study was to investigate the association between tinnitus and medial olivocochlear bundle (MOCB) malfunction. Potential suppression amplitude cut-off criteria that could differentiate participants with tinnitus from those without were sought. DESIGN: Mean suppression amplitudes of transient evoked OAEs and distortion product OAEs by contralateral white noise (50 dBSL) were recorded. Six mean suppression amplitudes criteria were validated as possible cut-off points. STUDY SAMPLE: The population consisted of normal hearing (n = 78) or presbycusic adults (n = 19) with tinnitus or without (n = 28 and 13, respectively) chronic tinnitus (in total, n = 138 78 females/60males, aged 49 ± 14 years). RESULTS: Participants with mean suppression values lower than 0.5-1 dBSPL seem to present a high probability to report tinnitus (specificity 88-97%). On the other hand, participants with mean suppression values larger than 2-2.5dBSPL seem to present a high probability of the absence of tinnitus (sensitivity 87-99%). Correlations were stronger among participants with bilateral presence or absence of tinnitus. CONCLUSIONS: This study seem to confirm an association between tinnitus and low suppression amplitudes (<1 dBSPL), which might evolve into an objective examination tool, supplementary to conventional audiological testing.

The report on the Universal Neonatal Hearing Screening Program in Poland between 2003 and 2015.

The Universal Neonatal Hearing Screening Program (UNHSP) has been operating in the whole Poland since 2003. Its main goals are to perform a screening hearing in the 2-3 day of life in every newborn baby in Poland and to gather information on risk factors of hearing loss. In total, 505 centers participate in the UNHSP on three reference levels. As of January 19th 2016, the central data base (CDB) of the UNHSP has records of 4,845,036 children, which comprises 96% of all children born in Poland. Hearing loss was diagnosed in 12,974 children, i.e. in 3 out of 1000 children. Here, we present the most important results and conclusions of the UNHSP.

Automated auditory response detection: Further improvement of the statistical test strategy by using progressive test steps of iteration.

OBJECTIVE: A common testing approach for automated ABR detection is to use a sequential test strategy. Repeated testing increases the error probability for a falsely detected response (Type I error rate). To compensate for this effect, the statistically critical test value must be increased with each test step. The aim of the study was to improve response detection by a reduction of the number of test steps using a progressively increasing test step of iteration, defined here as step width. DESIGN: A progressively increasing test step width was tested with and without the table-related testing (adjusting the critical test value to each test step) proposed by Stürzebecher & Cebulla (2013) . For this study the same data pool was used. STUDY SAMPLE: The investigation was performed on raw EEG data collected during routine clinical measurement of frequency-specific ASSR for hearing threshold assessment. RESULTS: The reduction of the test step number combined with a progressive test step width led to a significantly improved response detection. In combination with table-related testing a slight but not significant improvement compared to table-related testing alone was revealed. CONCLUSIONS: The proposed test strategy can improve the performance of objective hearing threshold assessment and of newborn hearing screening.

Identifying a context-effective school hearing screening test: An emic/etic framework.

OBJECTIVE: To identify a context-effective hearing screening test for primary schools in the Western Cape, South Africa using an emic-etic framework for test selection. DESIGN: A sequential mixed methods design was used to: (1) Identify test properties needed to successfully screen hearing in primary school children in the Western Cape, (2) select the hearing screening test most likely to succeed in this context, and (3) assess the use of the test in context. STUDY SAMPLE: Three nurses, two nursing assistants, two paediatric audiologists, and 100 grade-one children participated. RESULTS: Distortion product otoacoustic emissions (DPOAEs) were identified as the test most likely to succeed as a hearing screening test in primary school children in the Western Cape. While school nurses were able to successfully apply OAE testing in this context, its sensitivity to hearing loss in these children was 57.14%. CONCLUSIONS: The sensitivity would need to be improved before OAE testing could be used as a context-effective screening test for primary school children in the Western Cape. The study demonstrated the value of collaborative program planning using an emic-etic framework to ensure that screening tests are contextually appropriate.

Principles and guidelines for early intervention after confirmation that a child is deaf or hard of hearing.

This document is a supplement to the year 2007 position statement of the Joint Committee on Infant Hearing and provides comprehensive guidelines for establishing strong early intervention (EI) systems with appropriate expertise to meet the needs of children who are deaf or hard of hearing (D/HH). Optimal outcomes can only be achieved when there is high quality to the universal newborn hearing screening programs, the audiologic diagnostic process of confirmation that a child is D/HH and fitting of amplification, and the provision of appropriate, individualized, targeted, and high-quality EI services. There are 12 best practice guidelines for EI programs that include the provision of timely referral to EI services with providers who have knowledge and skills in early childhood deafness and hearing loss, infusion within the system of partnerships with parents as well as professionals who are D/HH, longitudinal developmental assessments for monitoring the child's development, data management systems that include developmental outcomes, a process to monitor the fidelity of the intervention, and appropriate services for children with additional disabilities, those from non-English speaking families, and those from special populations, including unilateral hearing loss and auditory neuropathy/dyssynchrony.

Tone, rhythm, and timbre perception in school-age children using cochlear implants and hearing aids.

BACKGROUND: Children with hearing impairments, especially those using hearing devices such as the cochlear implant (CI) or hearing aid (HA), are sometimes not encouraged to attend music classes, as they or their parents and teachers may be unsure whether the child can perform basic musical tasks. PURPOSE: The objective of the current study was to provide a baseline for the performance of children using CIs and HAs on standardized tests of rhythm and pitch perception as well as an instrument timbre identification task. An additional aim was to determine the effect of structured music training on these measures during the course of a school year. RESEARCH DESIGN: The Intermediate Measures of Music Audiation (IMMA) Tonal and Rhythmic subtests were administered four times, with 6 wk between tests. All children in the study were also enrolled in "Music Club" teaching sessions. Measures were compared between groups and across the four testing sessions. STUDY SAMPLE: Twenty children from a single school in Melbourne, Australia, were recruited. Eleven (four girls) had impaired hearing, including six with a unilateral CI or CI and HA together (two girls) and five with bilateral HAs (two girls). Nine were normally hearing, selected to match the age and gender of the hearing-impaired children. Ages ranged from 9-13 yr. INTERVENTION: All children participated in a weekly Music Club--a 45 min session of musical activities based around vocal play and the integration of aural, visual, and kinesthetic modes of learning. DATA COLLECTION AND ANALYSIS: Audiological data were collected from clinical files. IMMA scores were converted to percentile ranks using published norms. Between-group differences were tested using repeated-measures analysis of variance, and between-session differences were tested using a linear mixed model. Linear regression was used to model the effect of hearing loss on the test scores. RESULTS: In the first session, normally hearing children had a mean percentile rank of ∼50 in both the Tonal and Rhythmic subtests of the IMMA. Children using CIs showed trends toward lower scores in the Tonal, but not the Rhythmic, subtests. No significant improvements were found between sessions. In the timbre test, children generally made fewer errors within the set of percussive compared to nonpercussive instruments. The hearing loss level partially predicted performance in the Tonal, but not the Rhythmic, task, and predictions were more significant for nonpercussive compared to percussive instruments. CONCLUSIONS: The findings highlight the importance of temporal cues in the perception of music, and indicate that temporal cues may be used by children with CIs and HAs in the perception of not only rhythm, but also of some aspects of timbre. We were not able to link participation in the Music Club with increased scores on the Tonal, Rhythmic, and Timbre tests. However, anecdotal evidence from the children and their teachers suggested a wide range of benefits from participation in the Music Club that extended from increased engagement and interest in music classes into the children's social situations.

Comparing statistics for objective detection of transient and steady-state evoked responses in newborns.

OBJECTIVE: Receiver operating characteristic (ROC) methodology was used to compare the performance of different statistics in the automatic detection of multiple auditory steady-state responses (MSSR) and click auditory brainstem responses (cABR). STUDY SAMPLE: Thirty-five healthy newborns tested within the first two weeks of birth. DESIGN: In each case cABR and MSSR (0.5 and 2 kHz) were recorded with and without acoustic stimulation, using AUDIX equipment. With this test sample of recordings, ROC curves were evaluated separately for each statistic evaluated: (1) the standard deviation ratio (SDR) and the correlation coefficient ratio (CCR) for the cABR; (2) the Hotelling T2 (HT2) and circular T2 (CT2) for the MSSR. RESULTS: All objective detection methods performed well (areas under ROC (AUC) > 0.9). The MSSR statistics showed significantly larger AUCs at both frequencies (HT2: 0.98 and 1; CT2: 0.96 and 0.99) than the cABR measures (SDR: 0.91 and CCR: 0.92). The HT2 hits rate was the highest (97-100% at 0.5 and 2 kHz) for fixed false alarms rates of both 10 and 20%. CONCLUSIONS: This superiority of performance of T2-like statistics, reflecting inherent advantages of MSSR analysis for automation, warrants serious consideration for further development of newborn screening technology.

Detecting permanent hearing loss in newborns.

UNLABELLED: From year 2003, the UNHS nationwide survey was commenced in Italy by the Italian Institute of Social Medicine, and was conducted in all Italian maternity hospitals in 2003, 2006 and 2008. All maternity wards active in Italy were included. RESULTS: Our study showed that the coverage and penetration of the UNHS programmes in Italy has increased from 2003 to 2008. At the end of 2008, 324,537 newborns (60.6% of the total) were screened in Italian maternity hospitals. The referral rate before discharge varied from 2.6 to 16.7%, and this situation is reflected in a significant increase in costs. CONCLUSIONS: Considering the high cost of audiological confirmation, the first objective is to reduce the number of referred cases (false positives), by improving the training of screening personnel. In addition, close cooperation between audiological centres and maternity units and a dedicated secretariat team are important in increasing the efficacy of universal hearing screening. The investment in prevention will be repaid many times over.

How to motivate newborn hearing screening in the absence of a national programme: a collaboration between parents and professionals.

The establishment of the Italian Pediatric Federation Newborn Hearing Screening Network and the Italian Society of Neonatology Infant Hearing Study Group is the result of an international collaboration between Parents and Medical Professionals in order to promote an effective model in developing Early Hearing Detection Intervention Programs that recognize the role of parents as partners in the process. Among other factors, one important component frequently underestimated in most early intervention programs, both in the USA and other countries, involves the role of parental involvement within the Early Hearing Detection Intervention (EHDI) process. When a parent receives the news of their child's hearing loss, reactions may include, but are not limited to denial, grief, guilt, shame, fear and impotency. A parent may begin to ask certain questions: How do we know if the professionals in our children's lives are capable, educated, trained, up to date in their chosen fields of expertise? Do they respect our children and us as parents? Do they understand the needs of children who are deaf or hard of hearing? A life-long health professional - parental collaboration begins at the moment of the diagnosis of that child. When analyzing the habilitation process of a deaf child, the relationship between health professionals and the crucial role of parents in raising that child is a 50-50 shared responsibility. An objective of EHDI programs must be to empower parents by providing support from the beginning of the process. Distributing informative literature regarding the newborn hearing screening process and providing parents with access to resources such as parental support groups upon diagnosis equips parents with the tools necessary to immediately begin advocating for their children. The Italian Federation Pediatric Audiology Network was created by combining the parental perspective and medical protocols in order to establish the roots for stronger EHDI programs.

Investigation of a significant increase in referrals during neonatal hearing screening: a comparison of Natus ALGO Portable and ALGO 3i.

OBJECTIVE: Neonatal hearing screening programs in Flanders and the Netherlands use Natus ALGO screening devices. Since 2006 in Flanders and 2009 in the Netherlands, both programs have replaced the older ALGO Portable devices with the newer ALGO 3i devices. However, in both countries, ALGO 3i devices have a significantly higher rate of referrals than ALGO Portable devices. In Flanders, the refer rate has more than doubled with the switch to ALGO 3i devices. In the Netherlands, screening centers which used ALGO 3i devices also showed a significant increase in referrals. In both countries, the percentage of children diagnosed with permanent hearing loss remained approximately the same. DESIGN: A technical comparison of both device types was carried out to identify possible causes for the increase in referrals. The stimulus output of two ALGO Portable and three ALGO 3i devices was recorded and analysed for stimulus level, spectral properties, and stimulus irregularities. RESULTS: ALGO 3i devices stimulate at a peak level 4.6 dB lower than ALGO Portable devices, have a different stimulus spectrum and show unexplained stimulus irregularities during 4% of the stimulation time. CONCLUSIONS: A number of technical differences were found between both device types which could explain the increase in referrals.