Analysis of auditory function using brainstem auditory evoked potentials and auditory steady state responses in infants with perinatal brain injury

Hearing Loss Diagnosis and Early Hearing-Related Interventions in Infants With or at High Risk for Cerebral Palsy: A Systematic Review

AIM

To synthesize published evidence regarding hearing impairment diagnosis and interventions in infants with or at high risk for cerebral palsy in the first year after birth.

METHOD

Nine databases were searched for MeSH terms up to February 2020. Included studies were published in English, enrolled infants with or at high risk for cerebral palsy, and addressed hearing evaluation/rehabilitation within the first year after birth. Quality of evidence was evaluated using RTI Item Bank and QUADAS-2.

RESULTS

Eighteen articles met inclusion criteria. Quality of the evidence ranged from low to high, revealing variability in diagnostic assessment methodologies and adherence to diagnostic schedules. Concerns for bias included lack of recognition of cerebral palsy effects and etiologies on functional hearing assessment methods and results. Two interventions (hearing aid and cochlear implantation) were identified; however, reported use was inconsistent.

INTERPRETATION

Hearing screening in infants with or at high risk for cerebral palsy requires evaluation of the entire auditory pathway preferentially using comprehensive electrophysiological panels of assessments. For infants with perinatal neural insults, pediatric neurologists are uniquely positioned to recommend adherence to systematic surveillance and comprehensive audiology assessments, regardless of comorbidities and motor impairments.

Amplitude of low-frequency fluctuation may be an early predictor of delayed motor development due to neonatal hyperbilirubinemia: a fMRI study

BACKGROUND

Acute bilirubin encephalopathy or kernicterus is the worst consequence of brain damage caused by the elevation of total unbound serum bilirubin (TSB) in neonates. The present study aimed to visualize the characteristic brain regions of neonates with hyperbilirubinemia (HB) using functional magnetic resonance imaging (fMRI) and to measure the amplitude of low-frequency fluctuation (ALFF) values.

METHODS

This was a prospective cohort study, which included newborns with HB who were hospitalized at the Children's Hospital of Fudan University. The control group included neonates admitted with neonatal simple wet lung or pneumonia without neurological disease or brain injury. Newborns were divided into a severe hyperbilirubinemia group (SHB), moderate HB group, and control group based on TSB levels. The newborns completed routine MRI combined with fMRI scans and brainstem auditory evoked potentials (BAEPs) during their hospitalization.

RESULTS

A total of 251 newborns were included in this study. There were 45 patients in the SHB group, 65 in the HB group, and 141 in the control group. The average ALFF value in the basal ganglia region in the SHB group was the highest, which was greater than that in the HB and control groups (P<0.001). The ALFF increased with an increase in TSB concentration. Based on the results of the Bayley Scales of infant development assessment, we further found that the most significant difference in ALFF remained in the basal ganglia region between newborns with motor development scores above 70 (including 70) and below 70. Correlation analysis revealed a strong negative correlation between motor development scores and ALFF (r=-0.691, P<0.001). When ALFF alone was used to predict motor development, the sensitivity was 89%. When ALFF was combined with TSB and BEAP results, the area under the ROC curve was the largest (AUC =0.85). The sensitivity and specificity of the model were 67.86% and 90.77%, respectively.

CONCLUSIONS

The ALFF value may be able to serve as an early imaging biomarker and has a greater sensitivity than TSB or BAEP results in predicting long-term motor development (18 m) in HB.

Short-term outcome of brainstem auditory function in term infants after discharge from the neonatal intensive care unit

OBJECTIVES

To examine short-term outcome of brainstem auditory function in term infants after discharge from the neonatal intensive care unit (NICU).

METHODS

Brainstem auditory evoked response (BAER) was recorded and analysed at various click rates at 2-4 months of age in 43 term NICU graduates. The data were compared with those in age-matched normal controls.

RESULTS

The threshold of BAER in the NICU graduates was marginally elevated. The graduates also showed an increase in wave III latency at 91/s and wave V latency at all 21-91/s. The I-V interval was increased at 51 and 91/s, whereas the I-III and III-V intervals were slightly increased, with no significant differences from normal controls at any click rates. The amplitudes of waves I and V in the NICU graduates were moderately reduced at all click rates. Wave III amplitudes were reduced at 51 and 91/s. None of the slopes of BAER variables-rate functions in the NICU graduates differed significantly from normal controls.

CONCLUSIONS

The BAER was moderately abnormal in the NICU graduates, suggesting that brainstem auditory function is moderately impaired at 2-4 months of age after discharge. There is a need to monitor postnatal auditory and neural development for NICU graduates.

Development of Emotional Face Processing in Premature and Full-Term Infants

The rate of premature births has increased in the past 2 decades. Ten percent of premature birth survivors develop motor impairment, but almost half exhibit later sensorial, cognitive, and emotional disabilities attributed to white matter injury and decreased volume of neuronal structures. The aim of this study was to test the hypothesis that premature and full-term infants differ in their development of emotional face processing. A comparative longitudinal study was conducted in premature and full-term infants at 4 and 8 months of age. The absolute power of the electroencephalogram was analyzed in both groups during 5 conditions of an emotional face processing task: positive, negative, neutral faces, non-face, and rest. Differences between the conditions of the task at 4 months were limited to rest versus non-rest comparisons in both groups. Eight-month-old term infants had increases ( P ≤ .05) in absolute power in the left occipital region at the frequency of 10.1 Hz and in the right occipital region at 3.5, 12.8, and 16.0 Hz when shown a positive face in comparison with a neutral face. They also showed increases in absolute power in the left occipital region at 1.9 Hz and in the right occipital region at 2.3 and 3.5 Hz with positive compared to non-face stimuli. In contrast, positive, negative, and neutral faces elicited the same responses in premature infants. In conclusion, our study provides electrophysiological evidence that emotional face processing develops differently in premature than in full-term infants, suggesting that premature birth alters mechanisms of brain development, such as the myelination process, and consequently affects complex cognitive functions.

Analysis of audiological results of patients referred from newborn hearing screening program

CONCLUSION

As tools of confirmation of sensorineural hearing loss in neonates who are 'referred' from a newborn hearing screening program, both ASSR and DPOAE have high sensitivity and specificity. In addition, ASSR can be used as a substitute for ABR.

OBJECTIVES

To analyze the confirmative audiological results of patients referred from a newborn hearing screening program.

PATIENTS AND METHOD

From January 2007 to December 2013, hearing tests were performed on 474 babies (804 ears) who were 'referred' from the hospital or other maternity centers. Auditory brainstem response (ABR), auditory steady-state response (ASSR), and distortion product otoacoustic emissions (DPOAE) were used for hearing evaluation.

RESULTS

Of 474 babies (804 ears), 232 had normal hearing, while 242 babies (358 ears) had over 30 dB nHL threshold from ABR. Among the 156 babies (312 ears) who underwent both ABR and ASSR, the mean ASSR threshold had a strong correlation with ABR threshold (r = 0.942, p < 0.001). Assuming that ABR results were the yardstick of abnormal hearing, sensitivity and specificity of ASSR to ABR were 90.6% and 95%. DPOAE tests were performed on 180 babies (360 ears), with sensitivity of 85.9% and specificity of 84.4%.

Brainstem auditory evoked responses in an equine patient population. Part II: foals

Background

Reports of the use of brainstem auditory evoked response (BAER) as a diagnostic modality in foals have been limited.

Hypothesis/Objectives

To describe BAER findings and associated causes of hearing loss in foals.

Animals

Study group 18 foals (15 neonatal, 3 nonneonatal), control group (5 neonatal foals).

Methods

Retrospective. BAER records from the Clinical Neurophysiology Laboratory were reviewed from the years of 1982 to 2013. Peak latencies, amplitudes, and interpeak intervals were measured when visible. Clinical data were extracted from the medical records. Foals were grouped under disease categories. Descriptive statistics were performed.

Results

Ten neonatal foals had complete absence of BAER bilaterally and 5 had findings within reference range. Abnormalities were associated with common neonatal disorders such as sepsis, neonatal encephalopathy, neonatal isoerythrolysis, and prematurity. BAER loss also was observed in foals with specific coat color patterns such as completely or mostly white with blue irides or lavender with pale yellow irides. An American Miniature foal with marked facial deformation also lacked BAER bilaterally. One nonneonatal foal with an intracranial abscess had no detectable BAER peaks bilaterally, and 2 older foals, 1 with presumed equine protozoal myeloencephalitis and the other with progressive scoliosis and ataxia, had BAER within normal limits.

Conclusions and Clinical Importance

In neonatal foals, BAER deficits commonly are complete and bilateral, and associated with common neonatal disorders and certain coat and eye color patterns. Sepsis, hypoxia, bilirubin toxicity, and prematurity should be investigated as potential causes of auditory loss in neonatal foals.

Birth trauma--risk factors and short-term neonatal outcome

OBJECTIVE

The ability to predict birth trauma (BT) based on the currently recognized risk factors is limited and there is little information regarding the short-term neonatal outcome following BT. We aimed to identify risk factors for BT and to evaluate the effect of BT on short-term neonatal outcome.

METHODS

A retrospective, cohort, case-control study of all cases of BT in a single tertiary center (1986-2009). The control group included the two subsequent full-term singleton neonates who did not experienced BT. Short-term neonatal outcome was compared between the groups including Apgar scores, NICU admission, duration of hospitalization and neurologic, respiratory and metabolic morbidity.

RESULTS

Of the 118 280 singleton full-term newborns delivered during the study period, 2874 were diagnosed with BT (24.3/1000). The most frequent types of BT were scalp injuries (63.9%, 15.5/1000) and clavicular fracture (32.1%, 7.7/1000). The following factors were found to be independent risk factors for BT: instrumental delivery (OR 7.5, 95% CI 6.3-8.9), birth weight, delivery during risk hours, parity, maternal age and neonatal head circumference. Cesarean delivery was the only factor protective of BT (OR 0.2, 95% CI 0.2-0.3). Neonates in the study group had a prolonged length of hospital stay (3.3 versus 2.7 d, p = 0.001), were more likely to be admitted to the NICU (3.9% versus 1.9%, p < 0.001), and had a higher rate of jaundice (11.9% versus 7.1%, p < 0.001) and neurological morbidity (4.7% versus 2.3%, p < 0.001).

CONCLUSION

Instrumental delivery appears to be responsible for most cases of neonatal BT.

Brainstem auditory response findings in term neonates in intensive care unit

OBJECTIVES

Whether term infants in neonatal intensive care unit (NICU) have brainstem auditory abnormalities remains to be determined. This study aimed to detect any abnormality in brainstem auditory function in term neonates who are admitted to NICU.

METHODS

From a NICU, we recruited 55 term neonates with various perinatal problems. They were studied during the first week after birth using brainstem auditory evoked response (BAER), and the results were compared with normal term controls.

RESULTS

Wave I and III latencies and I-III interpeak interval of the evoked response in the NICU term neonates were similar to those in the controls. Wave V latency and I-V and III-V interpeak intervals tended to be increased at 21/s clicks. The increase was more obvious at higher rates 51 and 91/s. Analysis of variance revealed that at 21/s clicks only III-V interval was significantly increased (p < 0.05). At 51 and 91/s clicks, wave V latency and III-V and I-V intervals were significantly increased (p < 0.05-0.01). The rates of the abnormalities were seen more at higher than at lower click rates. The amplitudes of waves I, III, and V in the NICU neonates were all slightly reduced, but none differed significantly from the controls.

CONCLUSIONS

There are some abnormalities in BAER in term neonates in NICU, suggesting functional abnormality in the auditory brainstem in NICU infants.

Effect of hearing aids on auditory function in infants with perinatal brain injury and severe hearing loss

BACKGROUND

Approximately 2-4% of newborns with perinatal risk factors present with hearing loss. Our aim was to analyze the effect of hearing aid use on auditory function evaluated based on otoacoustic emissions (OAEs), auditory brain responses (ABRs) and auditory steady state responses (ASSRs) in infants with perinatal brain injury and profound hearing loss.

METHODOLOGY/PRINCIPAL FINDINGS

A prospective, longitudinal study of auditory function in infants with profound hearing loss. Right side hearing before and after hearing aid use was compared with left side hearing (not stimulated and used as control). All infants were subjected to OAE, ABR and ASSR evaluations before and after hearing aid use. The average ABR threshold decreased from 90.0 to 80.0 dB (p = 0.003) after six months of hearing aid use. In the left ear, which was used as a control, the ABR threshold decreased from 94.6 to 87.6 dB, which was not significant (p>0.05). In addition, the ASSR threshold in the 4000-Hz frequency decreased from 89 dB to 72 dB (p = 0.013) after six months of right ear hearing aid use; the other frequencies in the right ear and all frequencies in the left ear did not show significant differences in any of the measured parameters (p>0.05). OAEs were absent in the baseline test and showed no changes after hearing aid use in the right ear (p>0.05).

CONCLUSIONS/SIGNIFICANCE

This study provides evidence that early hearing aid use decreases the hearing threshold in ABR and ASSR assessments with no functional modifications in the auditory receptor, as evaluated by OAEs.