Hearing threshold assessment post grommet insertion. Is it reliable?

Clinical Decision Making for Intraoperative Auditory Brainstem Response Testing in Children following Tympanostomy Tube Placement

Intraoperative auditory brainstem response (ioABR) testing following tympanostomy tube (TT) placement may be biased due to temporary threshold shifts (TTS). The purpose of the study was to assess the evidence for TTS in children who have undergone ioABR using prolonged latencies of wave I (males > 1.95 ms, females > 1.88 ms) as a marker of a persisting air-bone gap. Eighty-three children underwent ioABR following surgical procedures at University Hospital Bonn, Germany. The primary outcome measure was the latency of wave I at 80-dB SPL. The total sample consisted of 66 males (79.5%) and 17 females (20.5%) with a mean (SD) age of 46.4 (26.6) months. Of 163 operated ears (83 children), 72 (44.2%) had no middle ear fluid, 19 (11.6%) serous fluid, and 72 (44.2%) mucoid fluid. The risk of having a prolonged latency of wave I at 80-dB SPL was OR 4.61 (95% CI 2.01-10.59; p < 0.001) in those with mucoid fluid as compared to those without mucoid fluid. Intraoperative ABR results should account for sex differences and be interpreted with caution and be verified. Ultimately, parents should be engaged in a preoperative discussion to decide if an ioABR should be postponed if mucoid fluid was found.

Assessment of the cochlear implant pathway for newborn hearing screening referrals

OBJECTIVE

To evaluate the cochlear implant (CI) assessment pathway for children referred through the newborn hearing screening programme (NHSP) and identify potential reasons for delay in CI surgery at a large UK centre.

METHODS

Retrospective analysis of electronic notes of children referred through NHSP from 2016 to 2019. Key points in the assessment pathway from referral to switch-on were assessed.

RESULTS

Of the 46 referrals, 44 went on to have CI surgery. Median age at CI surgery was 15 months (interquartile range (IQR) 13 to 17 months). Only 5% of referrals were implanted before the age of 12 months. Delayed referral and the presence of otitis media with effusion (OME) were associated with delayed implantation. The median period of monitoring for OME was 48 days (IQR 20 to 93 days), with a natural resolution rate of only 11%. The median time from surgery to switch-on was 5 weeks (IQR 4.1 to 5.4 weeks).

CONCLUSION

Achieving implantation prior to the age of 12 months for NHSP referrals can be challenging for a variety of reasons. The delays in the system and the steps that our implant programme has taken to address these will be highlighted.

Effect of Tympanostomy Tube Placement on Intraoperative Auditory Brainstem Response

BACKGROUND

 Intraoperative auditory brainstem response (ioABR) testing under general anesthesia is commonly performed on children when sleep-deprived ABR and behavioral testing are not reliable or feasible. Several studies have reported potential confounding results when tube insertion is combined with ABR testing.

PURPOSE

 This article evaluates whether a temporary threshold shift (TTS) occurs following placement of tympanostomy tubes (TTs) in children who undergo ioABR testing.

RESEARCH DESIGN

 A case-control prospective study. Patients scheduled for combined TT and ioABR procedures were enrolled into this study.

STUDY SAMPLE

 Twenty children (38 ears), ranging in age from 6 months to 10.5 years, were enrolled.

DATA COLLECTION AND ANALYSIS

 ABR thresholds for tone bursts with center frequencies of 2 and 4 kHz were compared before and after tube insertion. The indication for surgery, comorbidities, and status of the middle ear were also recorded. A paired t-test was used to determine statistical significance.

RESULTS

 Data collection did not necessarily indicate suctioning and tube placement were causing a TTS; however, fluid present in the middle ear space prior to TT placement appeared to influence results. Although a paired t-test did not show statistically significant differences in ABR thresholds between groups of individuals with and without fluid and before and after tube placement, 50% of patients with mucoid fluid (two out of four patients) were noted to have 10 dB or greater worsening in ABR thresholds in two out of six ears. Twenty-nine percent of patients with serous fluid (two out of seven patients) were noted to have at least a 10 dB worsening in ABR threshold in 2 out of 10 ears. Further testing is needed to confirm these trends.

CONCLUSION

 This pilot study indicates that children with mucoid or serous fluid may experience worse ABR thresholds following TT insertion. ioABR testing immediately after TT tube placement and in the presence of middle ear fluid should be interpreted with caution. Additional studies with a larger sample size are needed to confirm these results.

Follow-up audiometry after bilateral myringotomy and tympanostomy tube insertion

OBJECTIVE

There are no evidence-based guidelines regarding timing of postoperative audiometric follow-up for children undergoing tympanostomy tube insertion. Given the variability of follow-up among physicians, we attempt to guide the timing of postoperative audiograms using objective data.

STUDY DESIGN

Retrospective chart review.

METHODS

All pediatric patients undergoing primary bilateral myringotomy and tympanostomy tube insertion for otitis media with effusion who had audiometric data available at two follow-up times were identified from 2014. Patients were classified according to the type of audiometry performed and were further categorized into those who had tympanostomy tube insertion only and those who had concurrent adenotonsillectomies.

RESULTS

34 patients were included in the study. Among patients assessed by sound field audiometry, the mean sound field threshold value was 29.2dB preoperatively and improved to 21dB 2 weeks postoperatively and 17.9dB 6 to 10 weeks postoperatively. The difference between the two postoperative means was significant (p<0.0001). For patients evaluated by pure-tone audiometry, the mean preoperative air-bone gap was 20.1dB; this improved to 10dB at the first postoperative visit and 7.3dB at the second visit. The difference between the two means was significant (p<0.0001). For the subgroups in which adjunct adenotonsillectomy was performed, the greater improvement at the later follow-up was still statistically significant.

CONCLUSIONS

Progressive hearing improvement was demonstrated from 2 weeks to 6 to 10 weeks postoperatively. We recommend testing no fewer than 6 weeks after tympanostomy tube insertion. Earlier audiometry underestimates the degree of hearing improvement.

Clinical experience of auditory brainstem response testing on pediatric patients in the operating room

Objectives. To review our experience of conducting auditory brainstem response (ABR) test on children in the operating room and discuss the benefits versus limitations of this practice. Methods. Retrospective review study conducted in a pediatric tertiary care facility. A total of 267 patients identified with usable data, including ABR results, medical and surgical notes, and follow-up evaluation. Results. Hearing status successfully determined in all patients based on the ABR results form the operating room. The degrees and the types of hearing loss also documented in most of the cases. In addition, multiple factors that may affect the outcomes of ABR in the operating room identified. Conclusions. Hearing loss in children with complicated medical issues can be accurately evaluated via ABR testing in the operating room. Efforts should be made to eliminate adverse factors to ABR recording, and caution should be taken when interpreting ABR results from the operating room.

Pediatric hearing assessment by auditory brainstem response in the operating room

OBJECTIVES

To investigate the factors contributing to the discrepancies between auditory brainstem response (ABR) thresholds obtained in the operating room (OR) and hearing outcomes obtained in the follow-up period and to explore the benefits and limitations of performing ABR in the OR.

METHODS

A retrospective review study was conducted in a pediatric tertiary care facility. A total of 116 patients were identified with complete records, including OR-ABR results, medical examination and surgical procedure notes, and follow-up medical/audiological evaluation. Patients were divided into three groups: (1) 58 patients with middle ear effusion underwent myringotomy and tube placement, (2) 12 patients underwent myringotomy without tube placement, (3) 46 patients underwent ear examination only without effusion found. OR-ABR results were compared to audiological follow-up evaluations and analyzed for each group.

RESULTS

In patients with middle ear effusion and tube placement, the average threshold difference between OR-ABR and follow-up audiological evaluation was 9.7 dB (± 12.7), with highest discrepancy of 45 dB. On the other hand, in patients with dry ears and/or no tube placement, the average threshold difference was only 3.8 dB (± 8.6). Moreover, the discrepancy was more prominent in patients with mucoid effusion and larger at lower frequency, i.e., 1000 Hz.

CONCLUSIONS

The hearing thresholds estimated by ABR testing in the OR can be elevated and follow-up hearing evaluation after tube placement is needed. While ABR testing is valuable in the assessment of pediatric patients, especially for children who are difficult-to-test or have complicated medical conditions, caution should be taken when interpreting OR-ABR results.

The Role of Intraoperative Auditory Brainstem Response Testing for Infants and Difficult-To-Test Children

OBJECTIVE: To assess the validity of intraoperative auditory brainstem response in infants and difficult-to-treat older children.

STUDY DESIGN: Case series with chart review.

SETTING: Tertiary-level children's hospital.

SUBJECTS AND METHODS: Twenty-six patients were identified (mean age, 20 ± 18 months) who underwent both intraoperative auditory brainstem response (ioABR) testing and a follow-up hearing evaluation at five (standard deviation 4) months. Ears were analyzed separately for mean threshold change, and a sub-analysis was performed accounting for the presence or absence of fluid at the time of surgery.

RESULTS: A paired t test analysis indicated a statistically significant difference at 1 kHz. There was not a statistically significant difference between the two groups with click or 4-kHz testing. Fifteen ears (58%) at 1 kHz and 17 ears (49%) at 4 kHz frequencies, however, improved by 10 dB or more; 67 percent and 65 percent of these ears, respectively, had middle ear fluid intraoperatively. Eight ears (35%) in the click ABR group had a similar improvement, four of which had fluid at the time of surgery. Four ears in the 1-kHz (11.5%), in the 4-kHz (11.4%), and in the click ABR group (17.4%) demonstrated a 10-dB or worse threshold. The range of the discrepancy varied from a worsening in thresholds up to 20 dB and improvement in thresholds up to 45 dB.

CONCLUSIONS: We observed a significant discrepancy between ioABR and follow-up hearing thresholds. If ioABR indicates a hearing loss, audiologic testing should be performed at least several weeks later to confirm the results.