MB11 BERAphone and auditory brainstem response in newborns at audiologic risk: comparison of results

Cry features of healthy neonates who passed their newborn hearing screening vs. those who did not

OBJECTIVES

Temporal and fundamental frequency (fo) variations in infant cries provide critical insights into the maturity of vocal control and hearing performances. Earlier research has examined the use of vocalisation properties (in addition to hearing tests) to identify infants at risk of hearing impairment. The aim of this study was to determine whether such an approach could be suitable for neonates.

METHODS

To investigate this, we recruited 74 healthy neonates within their first week of life as our participants, assigning them to either a group that passed the ABR-based NHS (PG, N = 36) or a group that did not, but were diagnosed as normally hearing in follow-up check at 3 months of life, a so-called false-positive group (NPG, N = 36). Spontaneously uttered cries (N = 2330) were recorded and analysed quantitatively. The duration, minimum, maximum and mean fo, as well as two variability measures (fo range, fo sigma), were calculated for each cry utterance, averaged for individual neonates, and compared between the groups.

RESULTS

A multiple analysis of variance (MANOVA) revealed no significant effects. This confirms that cry features reflecting vocal control do not differ between healthy neonates with normal hearing, irrespective of the outcome of their initial NHS.

CONCLUSIONS

Healthy neonates who do not pass the NHS but are normal hearing in the follow-up (false positive cases) have the same cry properties as those with normal hearing who do. This is an essential prerequisite to justify the research strategy of incorporating vocal analysis into NHS to complement ABR measures in identifying hearing-impaired newborns.

Outcomes with OAE and AABR screening in the first 48 h--Implications for newborn hearing screening in developing countries

OBJECTIVE

Early discharge of newborns (<24h after birth) from birthing centres is an important barrier to successful newborn hearing screening (NHS) in developing countries. This study evaluated the outcome of NHS within the first 48 h using an automated auditory brainstem response (AABR) device without the need for costly disposables typically required, and transient evoked otoacoustic emissions (TEOAE).

METHODS

NHS was performed on 150 healthy newborns (300 ears) with TEOAE and AABR techniques before discharge at a hospital. A three-stage screening protocol was implemented consisting of an initial screen with TEOAE (GSI AUDIOscreener+) and AABR (BERAphone(®) MB 11). Infants were screened at several time points as early as possible after birth. Infants were only re-screened if either screening technique (TEOAE or AABR) initially yielded a refer outcome. The same audiologist performed all TEOAE and AABR screenings.

RESULTS

Over the three-stage screen AABR had a significantly lower refer rate of 16.7% (24/144 subjects) compared to TEOAE (37.9%; 55/145 subjects). Screening refer rate showed a progressive decrease with increasing age. For both TEOAE and AABR, refer rate per ear screened 24h post birth was significantly lower than for those screened before 24h. For infants screened before 12h post birth, the AABR refer rate per ear (51.1%) was significantly lower than the TEOAE refer rate (68.9%). Overall AABR refer rate per ear was similar for infants screened between 24 to 36 h (20.2%) and 36 to 48 h (18.9%) but significantly lower than for TEOAE (40.7% and 41.9%, respectively). Lowest initial refer rates per ear (TEOAE 25.8%, AABR 3.2%) were obtained after 48 h post birth.

CONCLUSION

In light of the early post birth discharge typical in developing countries like South Africa, in-hospital screening with AABR technology is significantly more effective than TEOAEs. AABR screening with a device like the MB 11 is particularly appropriate because disposable costs are negligible.

Sensitivity of ABR based newborn screening with the MB11 BERAphone(®)

OBJECTIVES

The aim of this study is to evaluate the sensitivity of our hearing screening program. The evaluation was done using a questionnaire for parents of children who participated in the NHS for a targeted time frame of two years. A survey was accomplished to identify children who passed our screening protocol in the newborn period, but who were later identified to have hearing loss.

METHODS

For the survey a one-year cohort was established in 2008 which included 500 children who received a hearing screening at our Center with the ABR newborn screener, MB11 BERAphone(®), two years before. Two hearing questionnaires were chosen for the survey. The LittlEARS questionnaire (MED-EL Medical Electronics GmbH) for investigating the hearing behavior of the children during the first two years of life and a second, custom-developed questionnaire (Würzburger questionnaire) investigating some aspects which are not included in the LittlEARS tool, such as speech/language development, general development as well as pathological factors that might eventually lead to a temporary hearing loss.

RESULTS

Analysis of the Würzburger questionnaires revealed normal speech development for 92.9% of the children. For 4.7% male and 2.4% female children delayed speech development was reported. Although twice as many males were found, the statistical comparison showed no significant difference according to gender. The results of the LittlEARS questionnaire are identical to those of the Würzburger questionnaire in 98.3% of the investigated cases and in 1.7% of the cases slightly different results but on borderline: The LittlEAR scores showed normal auditory development for the childrens' age but the Würzburger questionnaire results showed delayed speech development.

CONCLUSIONS

Based on the follow-up analysis and the results from the two questionnaires, no permanent hearing loss was found in any child two years after they passed the newborn hearing screening. Thus, we conclude that the sensitivity of the screening test was 100%, based on survey results 2 years post screening.

ABR-based newborn hearing screening with MB11 BERAphone® using an optimized chirp for acoustical stimulation

OBJECTIVE

At our center, the Maico MB11 BERAphone(®) device is used for newborn hearing screening based on Auditory Brainstem Responses (ABR). In 2006, an optimized chirp stimulus was implemented in the device to increase the reliability and quality of the screening method. In 2002, an automated response detection algorithm had been implemented. This study analyzes the screening results using the MB11 BERAphone(®) device with the implemented chirp stimulus and automated response detection method.

METHODS

The data presented were collected in the well-baby nursery as part of the newborn hearing screening program following a two stage screening protocol. To focus the study on the typical routine screening, data from at-risk babies were not included. Overall, data from 6866 babies (3604 males and 3262 females) screened from March 2006 to April 2011 were analyzed in this study.

RESULTS

Out of the 6866 babies screened, 6607 passed bilaterally prior to hospital discharge (defined as 1st stage in this hearing screening program). Therefore, the pre-discharge pass rate of the hearing screening with the MB11 BERAphone(®) device was 96.2%. The resulting referral rate was 3.8%. The median test time per ear (excluding time for preparation and data reporting) was 28s with a range of 15-112s (5-95th percentile). The number of infants referred for 2nd stage, post-discharge re-screening was 259. Of this group, 71 passed bilaterally and 188 failed the re-screening in one or both ears. Therefore, including both the pre-discharge and post-discharge screening results, the bilateral pass rate was 97.3% and 2.7% were referred for diagnostic evaluation. Diagnostic testing was performed on all of the 188 infants who were referred. Results showed that 47 of these babies had hearing loss. This equates to a positive predictive value for a refer result of 25%. The observed prevalence of hearing impairment in our population was 0.684%. Diagnostic results for 141 of the referred newborns proved that they had normal hearing. That is, 141 out of 6866 newborns had a false-positive result with the MB11 BERAphone(®) screening. Therefore, the device had a specificity of 97.9%. During the time period of this study, no baby who passed the hearing screening was later found to have hearing impairment, suggesting a sensitivity of 100%. However, due to the limited number of newborns and the short time period after screening for the more recently screened babies, a reliable estimate of the sensitivity cannot be yet made from our program statistics. The theoretical sensitivity of the MB 11 device is 99.9%.

CONCLUSIONS

The Maico MB11 BERAphone(®) is a reliable device for auditory brainstem response newborn hearing screening and it provides results within a very short time. Due to the implemented method for automatic detection of ABR, the use of the device does not require an experienced examiner, allowing it to be used by trained technicians in locations outside the department of audiology such as the well-baby nursery.

MB11 BERAphone) hearing screening compared to ALGOportable in a Dutch NICU: a pilot study

OBJECTIVE

Since 2001 all Dutch Neonatal Intensive Care Units use a highly reliable automated auditory brainstem response (AABR) newborn hearing screening device, the (ALGOportable). A more recent AABR newborn hearing screening device, the MB11 BERAphone, does not make use of disposable ear couplers and has a different algorithm, a possible advantage with regard to a faster response acquisition. Use of the MB11 BERAphone is therefore potentially more cost effective and faster. This study compares test results and suitability of the MB11 BERAphone to the ALGOportable as reference AABR hearing screening test for newborns during neonatal intensive care admission.

METHODS

In 54 NICU graduates [median GA 31 2/7 weeks, median BW 1760 g] 55 (110 ears) hearing screening test results and total test time were examined with both the MB11 BERAphone and ALGOportable. Test time was measured from the start of the procedure, including child preparation, until a bilateral result (pass/refer) was obtained.

RESULTS

The median postconceptional age of testing was 34 3/7 weeks (range 30-41 6/7). In 3 ears MB11 BERAphone screening failed due to continuous myogenic activity. In 104/107 ears final results were congruent [87/107 (81%) pass; 17/107 (16%) refer] leaving an incongruity in 3 ears of 2 infants: MB11 BERAphone "refer" and ALGOportable "pass". Diagnostic investigative audiology confirmed a 35dB unilateral conductive hearing loss in 1 child. At 15 months of age speech and language development in the other child was normal. When using the ALGO portable as reference test, the sensitivity of the MB11 BERAphone is 100% (17/17), specificity 97% (87/90). The mean MB11 BERAphone test time was slightly, but not significantly, shorter 11.4 min (SD 6.6) than with the ALGOportable 13.9 (p<0.08).

CONCLUSION

The MB11 BERAphone is a reliable and feasible hearing screening device for use with NICU graduates under NICU circumstances. It is potentially more cost effective than the ALGOportable.

Evaluation of an automated auditory brainstem response in a multi-stage infant hearing screening

An automated auditory brainstem response (AABR) method, the Maico MB-11 with BERAphone, has been developed for hearing screening in newborns. The aim of this study was to test the validity of this automated ABR screening method in a multistage newborn hearing screening (NHS). We applied a "five level" protocol using transient evoked otoacoustic emission (TEOAE), AABR-MB-11 with BERAphone and conventional auditory brainstem response (ABR). TEOAE, AABR, and conventional ABR testing were performed by ENT specialists experienced in neonatal screening techniques. Among the 8,671 newborns tested (males 3,889; females 4,782), only 42 newborns were lost to follow-up and the final false-positive rate was of 0.03%. Our experience highlights that for the neonatal period, conventional auditory brainstem response is the most reliable method for assessing the hearing level and minimizing the false-positive rate. Although AABR (performed by ENT specialists experienced in neonatal screening techniques) is easy to use, fast and with a good compliance, the device is unable to provide accurate and certain diagnosis on the degree of hearing loss to allow a proper treatment.