Brainstem Auditory Evoked Potentials Research Articles

Awake craniotomy with dexmedetomidine during resection of brain tumours located in eloquent regions.

An awake craniotomy (AC) is the gold standard for the resection of supra-tentorial brain tumours in eloquent areas. Intraoperative monitoring "on-demand" of essential eloquent brain functions and the increasing need to preserve higher intellectual functions during surgery requires aunique anaesthetic approach during AC. Dexmedetomidine is considered the first-choice pharmacological agent for sedation during AC. Twenty-six patients with asingle brain tumour located in areas of eloquent brain function were enrolled in this prospective study. The patients underwent AC under conscious sedation. Motor-evoked potentials and brainstem-evoked auditory potentials were measured using neurophysiological tests during surgery to assess brain potentials. Intraoperative brain relaxation was reached using amodified Bristow scale. Neuromonitoring and psychological tests were maintained until meningeal closure. All operations were carried out successfully, and no reoperations were needed. No significant impact on circulatory and respiratory parameters was observed during conscious sedation based on dexmedetomidine. Neither instrumental airway support nor conversion to general anaesthesia was necessary. Brain relaxation was good in 84% of cases. Intraoperative epileptic episodes were observed in 15% of the patients. Neuro-logical and psychological monitoring was satisfactory. Unaltered muscle force was observed postoperatively in 88% of the patients. AC performed under conscious sedation, and dexmedetomidine infusion without instrumental airway support, was safe and well-tolerated by patients with comfortable physiological sleep for most of the procedure. This approach to AC was associated with minimal risk of perioperative adverse events and may be particularly beneficial in patients with severe comorbidities.

Comparative Effects of Valganciclovir and Ganciclovir on the Congenital Cytomegalovirus Infection and Hearing Loss: A Randomized Controlled Trial

Background: Cytomegalovirus (CMV) is a highly specific herpes virus spreading only from person to person. Valganciclovir (VGCV) and ganciclovir (GCV) are effective in the treatment of neonatal congenital CMV infection. Objectives: This study aimed to compare the curative effects of VGCV and GCV among neonates with CMV infection and evaluate their effects on hearing. Methods: A total of 48 neonates with congenital CMV infection admitted to Huaian Maternal and Child Health Care Hospital, China, were selected from January 2016 to December 2019 and randomly divided into two equal groups of intervention and group (n = 24 each). While the control group received intravenous injection of GCV, the intervention group received oral VGCV. After a 6-week course of treatment, polymerase chain reaction (PCR) was applied to detect the CMV load in both urine and blood. We used the ELISA method to detect the serum CMV-IgM expression level before and after treatment. Moreover, we compared the positive rates of CMV-DNA and CMV-IgM, hyperbilirubinemia, retinitis, hepatosplenomegaly, thrombocytopenia, neutropenia, as well as the results of hearing screening and brainstem auditory evoked potentials (BAEP). Results: Before treatment, there was no statistical difference in blood/urine CMV-DNA expression level and positive expression rates of blood/urine CMV-DNA and CMV-IgM between the groups (P > 0.05). After treatment, blood/urine CMV-DNA expression and the positive expression rates of blood/urine CMV-DNA and CMV-IgM significantly decreased in both groups compared to before treatment (P < 0.05), but there was no statistical significance between the two groups (P > 0.05). Before treatment, there was no significant difference in hearing abnormality rates between the control (50%) and intervention (62.5%) groups (P > 0.05). After treatment, both the control (20.83%) and intervention (29.17%) groups had significantly decreased hearing abnormality rates, and the difference was statistically significant compared with before treatment (P < 0.05), but the difference between the two groups was not statistically significant (P > 0.05). After treatment, the results of comparing BAEP showed that both groups had no statistically significant differences in the number of neonates with normal hearing, mild hearing loss, moderate to severe hearing loss, severe hearing loss, and extremely severe hearing loss (P > 0.05). Before treatment, both groups had no statistically significant differences in the number of neonates with hyperbilirubinemia, retinitis, hepatosplenomegaly, thrombocytopenia, and neutropenia (P > 0.05). After treatment, while the number of neonates with hyperbilirubinemia, retinitis, hepatosplenomegaly, and thrombocytopenia decreased, neutropenia cases increased, and the difference before and after treatment was statistically significant (P < 0.05); however, the difference between the two groups was not statistically significant (P > 0.05). Conclusions: VGCV is similar to GCV in the treatment of neonatal congenital CMV infection, but the oral route of administration of VGCV is more acceptable among neonates.

Auditory evoked potentials in children and adolescents with multiple sclerosis and neuromyelitis optica spectrum disorders

BackgroundIn children, an acute demyelinating disease may evolve as a multiphasic disease with multiple relapses, such as multiple sclerosis (MS) and neuromyelitis optica spectrum disorder (NMOSD). The Brainstem Auditory Evoked Potentials (BAEP) and Long-Latency Auditory Evoked Potentials (LLAEP) contribute to the identification of either retrocochlear changes or other central auditory nervous system (CANS) changes. ObjectivesTo characterize BAEP and LLAEP in children and adolescents with MS and NMOSD and verify the diagnostic values of these potentials in each of the demyelinating diseases. MethodsThe 40 participants were divided into two study groups (SG1 – MS, SG2 – NMOSD) and two comparison groups (CG1 and CG2), matched for age (9 years–17 years and 11 months) and sex. Electrophysiological hearing assessment was performed with BAEP and LLAEP. ResultsWhen SG1 and SG2 were compared with CG1 and CG2 regarding BAEP and LLAEP, both SG1 and SG2 presented a higher occurrence of changes. Also, individuals with MS had higher occurrences of BAEP changes, whereas individuals with NMOSD had a higher occurrence of LLAEP changes. ConclusionsBAEP and LLAEP in children and adolescents with MS or NMOSD showed higher latencies and lower amplitudes of some components when these individuals were compared with their peers. These procedures were highly accurate to identify demyelinating diseases. BAEP results were more abnormal in individuals with MS, while LLAEP was so with NMOSD. These findings indicate that the auditory evoked potentials are important instruments for the differential diagnosis of MS and NMOSD, and valuable to monitor disease evolution.

A Pilot Study for Gender Variation and Correlation of Anthropometric Parameters on the Variables of Brainstem Auditory Evoked Potentials in Audiometrically Normal Young Adults

Head size gender and BMI have found to have correlation with Brainstem Auditory Evoked Potentials (BAEPs) in some studies but other have expressed doubts. There is no common consensus. To add to the complexity, the range of normative values also vary. The present pilot study was done aiming to study effect of gender and anthropometric parameters on the variables of BAEPs in audiometrically normal young adults and collect normative values for further studies. This was an observational prospective, cross sectional, pilot study conducted among 100 medical students with 50 males and 50 females. The selected students fulfilled the inclusion and exclusion criteria and had given informed consent for the study. In the study RMS EMG EP MARK II machine was used to measure and record the absolute, interpeak and wave amplitudes. The data was collected and statistically analysed. The BAEP measurements from the subjects were compared with gender and anthropometric measurements. The age of students enrolled in subject ranged from 18–21 years. The difference between Left and Right ears Wave I, III and V, besides I-Ia and V-Va difference was found to be significant; while differences between male and female peak latencies of Wave III (left and right) and V (left and right) and Wave IV right ear, I-V IPL and V-Va of Right ear were found to be statistically significant. BMI did not show any statistically significant correlation with BAEPs. AEP results were definitely individual effected by gender, with latency duration more among males than females in most BAERs but were significant in few. The head circumference of a person appears to affect the BAER. BMI in the study was not significant with BAER variables.

Brainstem auditory evoked potential combined with high resolution cranial base CT can optimize the diagnosis of auditory nerve injury

PurposeAuditory nerve injury is one of the most common nerve injury complications of skull base fractures. However, there is currently a lack of auxiliary examination methods for its direct diagnosis. The purpose of this study was to find a more efficient and accurate means of diagnosis for auditory nerve injury. MethodsThrough retrospectively analyzing the results of brainstem auditory evoked potential (BAEP) and high-resolution CT (HRCT) in 37 patients with hearing impairment following trauma from January 1, 2018 to July 31, 2020, the role of the two inspection methods in the diagnosis of auditory nerve injury was studied. Inclusion criteria were patient had a clear history of trauma and unilateral hearing impairment after trauma; while exclusion criteria were: (1) severe patient with a Glasgow coma scale score ≤5 because these patients were classified as severe head injury and admitted to the intensive care unit, (2) patient in the subacute stage admitted 72 h after trauma, and (3) patient with prior hearing impairment before trauma. According to Goodman's classification of hearing impairment, the patients were divided into low/medium/severe injury groups. In addition, patients were divided into HRCT-positive and negative groups for further investigation with their BAEP results. The positive rates of BEAP for each group were observed, and the results were analyzed by Chi-square test (p < 0.05, regarded as statistical difference). ResultsA total of 37 patients were included, including 21 males and 16 females. All of them were hospitalized patients with GCS score of 6–15 at the time of admission. The BAEP positive rate in the medium and severe injury group was 100%, which was significantly higher than that in the low injury group (27.27%) (p < 0.01). The rate of BEAP positivity was significantly higher in the HRCT-positive group (20/30, 66.7%) than in the HRCT-negative group (1/7, 14.3%) (p < 0.05). Twenty patients (54.05%) were both positive for BEAP and HRCT test, and considered to have auditory nerve damage. Six patients (16.22%) were both negative for BEAP and HRCT test, and 10 patients (27.03%) were BAEP-negative but HRCT-positive: all the 16 patients were considered as non-neurological injury. The rest 1 case (2.70%) was BAEP-positive but HRCT-negative, which we speculate may have auditory nerve concussion. ConclusionBy way of BAEP combining with skull base HRCT, we may improve the accuracy of the diagnosis of auditory nerve injury. Such a diagnostic strategy may be beneficial to guiding treatment plans and evaluating prognosis.

Study of brainstem auditory evoked response and biochemical markers in patients of alcohol use disorder

Objectives: Data available on brainstem auditory evoked response (BAER) and its correlation with biochemical parameters in patients of alcohol use disorder (AUD) in Indian population is scanty. Therefore, this study was undertaken to focus on the effects of AUD on BAER and liver enzymes. Materials and Methods: This case-control study included 40 males in the study group who had AUD and 40 healthy males in the control group in the age group of 20–60 years. The BAER was performed using octopus NCS/ EMG/EP (Clarity) machine. The levels of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase and serum bilirubin were estimated in all the subjects. Results: We observed a highly significant increase in the absolute latencies of waves III and V and interpeak latencies (IPL) I-III and I-V of BAER in the patients of AUD in this study. Significant increase in the liver enzymes and especially AST/ALT ratio of patients of AUD was seen which indicated towards subclinical alcoholic hepatitis. The latencies of waves of EPs (waves III, V, IPL I-III and IPL I-V) were positively correlated with the biochemical parameters and duration of AUD. Conclusion: Our findings indicated that AUD lead to the increase in brainstem transmission time and also lead to subclinical alcoholic hepatitis which is reflected by the increase in the liver enzymes. We concluded that chronic alcohol consumption affected the auditory pathways and delayed the auditory transmission time which was suggestive of possible demyelination of auditory tracts.

Intraoperative neurophysiologic monitoring in microvascular decompression for hemifacial spasm

The majority of primary hemifacial spasm (HFS) patients are related to a vascular compression of the facial nerve root at its entry zone. Non-surgical treatment methods of HFS are anti-epileptic drugs and local botulinum toxin injection, but their outcomes are often not satisfactory in relieving symptoms. Microvascular decompression (MVD) is a surgical treatment method of HFS. Nowadays, intraoperative neurophysiologic monitoring is being used during MVD for two main objectives. The first and main objective is to prevent and reduce the risk of hearing impairment. Brainstem auditory evoked potentials (BAEPs) is monitored during surgery, to monitor the cranial nerve VIII and determine hearing sense preservation. Researches on BAEPs has enabled near real-time and safe monitoring, as warning indicators and advanced techniques to get results faster has been discovered. The second objective is to optimize the effectiveness of surgery. Despite the surgery, some patients had persisted symptoms or recurrence of spasm for some reasons, in few cases. The lateral spread response (LSR) monitoring is performed to guide the operator during surgery. LSR shows modest sensitivity. Nevertheless, it shows high specificity in predicting the symptom-free status after MVD. Low sensitivity precluded the use of the LSR monitoring as an exclusive solitary diagnostic modality. The disappearance of LSR during MVD appears to be not effectively in predicting long-term outcomes, but it demonstrated limited prognostic values in predicting favorable short-term outcomes. These results implements that, intraoperative monitoring of LSR during MVD can provide considerable value for investigating the adequacy of MVD before cranial bone closure.

Effects of neurodevelopmental risk factors on brainstem maturation in premature infants.

Interpeak latencies (IPL), as measured by the auditory brainstem-evoked responses (ABR) test, represent the conduction time, and therefore the maturation of the brainstem auditory pathway. We aimed to study the effect of various risk factors for the neurodevelopmental delay on the conduction time in the auditory pathway among normal hearing premature infants, at term postmenstrual age (PMA). Retrospective analysis of 239 premature infants (gestational age 32.5 ± 2.1 weeks, birth weight 1827 ± 483 g). Interpeak latencies, demographic data, and risk factors were recorded. Sex, PMA at ABR test, being small for gestational age (SGA), intraventricular hemorrhage (IVH) or periventricular leukomalacia (PVL), and days of invasive ventilation were found to significantly affect the IPL's in the auditory pathway in a univariate analysis. Multivariable regression analysis revealed that male sex and less advanced PMA at the examination were independent factors associated with prolonged IPL's, while bronchopulmonary dysplasia, IVH or PVL and being SGA shortened the IPL's. Non-invasive mechanical ventilation, did not affect the caudal part of the auditory pathway, despite its high noise level. Among various risk factors for the neurodevelopmental delay, male sex was associated with delayed, while IVH or PVL, BPD and SGA could be associated with accelerated auditory brainstem maturation. Auditory brainstem-evoked response (ABR) test, among normal hearing infants, can serve as a clinical tool to assess brainstem auditory maturation. Different neurodevelopmental risk factors could have different effects on the maturity of the auditory pathway. Male sex is significantly associated with prolonged interpeak latencies (IPL) among preterm and term infants, while intraventricular hemorrhage or periventricular leukomalacia, bronchopulmonary dysplasia, and being small for gestation age may be associated with shortened IPL The corrected age at ABR testing is of significance, among preterm and term infants.

The use of facial nerve fasciculus motor evoked potential (MEP) as intraoperative neurophysiological monitoring modality in a child with a diffuse intrinsic pontine glioma: A case report.

BackgroundIntraoperative neurophysiological monitoring (IONM) has improved the diagnosis and surgical treatment of brainstem and posterior fossa tumors. Several modalities are available for IONM such as electroencephalography, brainstem mapping (BSM), cranial nerves evoked potentials), somatosensory evoked potentials (SEP), motor evoked potentials (MEP), brainstem auditory evoked potentials (BAEPs), nerve conduction, and electromyography (EMG) signals. Though motor evoked potential (MEP) and brainstem mapping are the most common IONM modalities used for surgical management of brainstem gliomas, cranial nerve potentials can also be of great help.Case descriptionThis article describes a 10-year-old child with diffuse intrinsic pontine glioma (DIPG) who presented with gradual progressive crossed hemiparesis. His brain images carried a range of potential differential diagnoses. Her underwent a successful brainstem biopsy via using motor evoked potential for facial nerve without injuring nearby structures.ConclusionMotor evoked potential of the facial nerve can be used solely for biopsy taking in cases of DIPG.

To Study the Effect of Vitamin C Supplementation on Brainstem Auditory Evoked Response in Diabetic Patients with Neuropathy

To Study the Effect of Vitamin C Supplementation on Brainstem Auditory Evoked Response in Diabetic Patients with Neuropathy

Clinical characteristics of patients with young-onset hemifacial spasm: a retrospective analysis of 151 cases

Objective The average age of hemifacial spasm (HFS) onset is mostly between the fifth and sixth decades of life, with a relatively low incidence in younger age groups. The objective of this study was to analyze the characteristics and clinical outcomes of young-onset hemifacial spasm (YOHFS). Methods Between April 1997 and March 2021, 151 HFS patients aged 30 years or younger at the time of microvascular decompression (MVD) were selected. We analyzed their epidemiological characteristics, intraoperative findings, improvements, and postoperative complications by reviewing medical records. Results This study included 151 patients who underwent MVD. The average age of the patients was 26 years. The mean symptom duration was 36.5 months. The male-to-female sex ratio was 1:1.5. The most common offending vessel was the anterior inferior cerebellar artery, and the most common compression type was the arachnoid type. Improvements in spasm after MVD were seen in 96.7% of patients. No permanent facial palsy was noted after MVD. Changes in brainstem auditory-evoked potentials were recorded in 11 patients; however, no permanent hearing loss was observed. Conclusion The characteristics and clinical outcomes of YOHFS in this study were similar to those of patients with HFS in the general population. Based on the clinical outcomes, MVD for YOHFS is effective and safe. Therefore, MVD should be considered in patients with YOHFS. KEY WORDS: Hemifacial spasm, Microvascular decompression surgery, Prevalence

Brainstem Auditory Impairment in Very Preterm Infants who Experience Chronic Sublethal Hypoxia

Very preterm infants who suffer from bronchopulmonary dysplasia (BPD), a major neonatal complication, often experience frequent episodes of hypoxaemia or prolonged hypoxaemia, resulting in significant chronic sublethal hypoxia (CSH). Whether the CSH occurring during the neonatal period exerts any adverse effect on the immature brainstem auditory system remains a topic of attracting considerable interest. With brainstem auditory evoked response (BAER) and particularly maximum length sequence (MLS) BAER, recent investigators have revealed that neonatal BPD damages functional integrity of the immature brainstem auditory system. There are significant abnormalities in the BAER components that reflect central neural function of the auditory brainstem. By comparison, there are only mild abnormalities in the BAER components that reflect peripheral neural function of the auditory brainstem. Clearly, CSH associated with neonatal BPD damage central neural conduction, suggesting impaired myelination and synaptic dysfunction, in the immature auditory brainstem, but exerts limited effect on peripheral neural function of the brainstem. These abnormalities tended to be improved after term date. CSH occurring during the neonatal period damages myelination of the central auditory system, which tends to be alleviated after term date.

Mice heterozygous for the Serpinb6a null mutation show deficits in central auditory function after acoustic trauma.

Complete deficiency of the serine protease inhibitor gene, SERPINB6, is responsible for autosomal-recessive, nonsyndromic sensorineural hearing loss in humans. A mouse model of this deafness gene identifies Serpinb6a expression in the neurosensory epithelium and fibrocytes of the cochlea. Homozygous Serpinb6a mutant mice display an exaggerated hearing loss after exposure to moderate acoustic trauma. It is unknown if and how heterozygous Serpinb6a mice show increased vulnerability to acoustic trauma. We exposed Serpinb6a+/- and Serpinb6a+/+ mice to acoustic trauma and measured their hearing function prior to, 3 and 14 days postexposure, analysing shifts in hearing threshold and amplitudes of Wave I and II of the auditory brainstem-evoked response (ABR) to 4, 8, 16 and 32 kHz tones. Shifts in hearing threshold and Wave I amplitude of Serpinb6a+/- mice were not significantly different from Serpinb6a+/+ mice at both time points and all frequencies tested (P > 0.05, Mann-Whitney test). However, Wave II amplitudes at 16 and 32 kHz tones, were more severely diminished in Serpinb6a+/- mice (P < 0.05). To exclude any effects of ageing on auditory function in Serpinb6a+/- mice, hearing function of unexposed Serpinb6a+/- mice was measured at start and end of the experimental period. The shift in Wave II amplitude of exposed Serpinb6a+/- mice was significantly lower than unexposed Serpinb6a+/- mice only at 16 and 32 kHz (P < 0.01), confirming acoustic trauma as the main cause of hearing deficits in Serpinb6a+/- mice. These results suggest that heterozygous Serpinb6a humans may be vulnerable to noise.

Normalización de los Potenciales Evocados Auditivos del Tronco Cerebral I: Resultados en una muestra de adultos normoyentes

Este artículo es el primero de una serie de estudios que tienen por objeto describir las características de los Potenciales Evocados Auditivos del Tronco Cerebral (PEATC) tanto en sujetos normoyentes como hipoacúsicos. En la interpretación de estos registros electrofisiológicos es necesario conocer los valores de normalidad de la latencia y amplitud de los principales componentes y su relación con la distintas intensidades así como los valores de los intervalos interondas y las posibles diferencias interaurales. Estos valores de normalidad varían en función de múltiples factores como el sexo, la edad, los parámetros de estimulación y de registro o las condiciones en las cuales se llevan a cabo los PEATC. En este primer trabajo se describen los valores de normalidad de latencia de los componentes de los PEATC utilizando para ello los parámetros de estimulación y de registro propios de nuestro laboratorio en una muestra de sujetos adultos normoyentes.

Comparative Analysis of Brainstem Auditory Evoked Potential Patterns between Menstruating and Menopausal North Indian Females.

Introduction:Various studies suggest a significant impact of gonadal hormones on many neuronal functions, including auditory processing. Although a few researchers have independently investigated the brainstem auditory evoked potential (BAEP) patterns during various phases of menstrual cycle and also during menopause, there is an acute paucity of comparative data between their BAEP patterns. This study was conducted to compare the BAEP patterns between normally menstruating females and menopausal females from North India.Materials and Methods:A cross-sectional study was done on 90 females aged 17–21 years who were in the follicular phase of their menstrual cycle and 100 menopausal females aged 46–70 years. BAEP recording was done using standardized protocol. The data were analyzed using SPSS software. It contained mean wave latencies I, II, III, IV, V, and Interpeak Latencies (IPL) I-V, I-III, and III-V.Results:The mean values of latencies of waves I, III, and V and also of IPL I-III, I-V, and III-V were significantly higher (P > 0.05) in menopausal females. However, the difference between mean values of wave latencies II and IV of both groups was statistically non-significant (P > 0.05).Conclusion:The increased latencies in menopausal females indicate subtle degenerative changes that start appearing within the central auditory pathway after menopause and are probably due to a decline in ovarian hormones, especially estrogen.

Conversion from clinically isolated syndrome to multiple sclerosis: what paraclinical tests findings are the most characteristic?

Background. Multiple sclerosis (MS) is a chronic demyelinating disease with clinical onset usually manifesting as clinically isolated syndrome (CIS). Approximately 70% of people with CIS convert to MS. Therefore, there is a pressing need to identify the most characteristic paraclinical test findings to predict CIS conversion to MS.Aim. The aim of this study was to establish the most characteristic paraclinical test findings for the identification of CIS conversion to MS.Materials and methods. A retrospective data analysis was performed in patients diagnosed with demyelinating encephalomyelitis according to ICD-10 (International Classification of Diseases Tenth Revision), codes G37.8 (other specified demyelinating diseases of central nervous system) and G37.9 (demyelinating disease of central nervous system, unspecified). In clinical practice, these diagnoses are called CIS. The data were obtained from medical records and included findings of paraclinical tests (magnetic resonance imaging (MRI), IgG levels and oligoclonal bands (OCBs) in cerebrospinal fluid (CSF), and brainstem auditory evoked potential (BAEP)) and final diagnosis. The patients were divided into 2 groups according to the final diagnosis (MS group and non-MS group) and into 3 age groups (18-30, 30-50, &gt;50 years old). The prevalence and statistical difference of paraclinical tests were estimated between the groups. Chi-squared test was used to compare between categorical variables. Mann-Whitney U test was used to compare between the groups. The association between two quantitative variables was determined using Spearman correlation co-efficient. Results were interpreted as statistically significant when p-value &lt;0.05.Results. A total of 138 cases were included in the study. 49 patients converted to MS (35.5%), other 89 patients (64.5%) were diagnosed with other diseases than MS. Unspecified MRI lesions (χ2=4.328, p=0.037, n=40), elevated IgG levels (χ2=10.793, p=0.001, n=36), and positive OCBs in CSF (χ2=34.859, p&lt;0.001, n=30) were more prevalent in MS group compared to non-MS group. Moreover, lesions detected by the BAEP test were also more frequent among MS group (χ2=10.924, p&lt;0.001, n=17).Conclusions. The results indicate that pathological CSF findings (positive OCBs, elevated IgG levels) and prolonged BAEP latency are characteristic in patients with CIS who later progress to MS. Unspecified brain MRI lesions are also distinctive for MS patients; however, this result should be interpreted with consideration due to methodological reasons

Auditory brainstem response: An overview of neurophysiological implications and clinical applications -A Narrative Review.

Evoked Potentials are electrical potentials that occur in a group of neurons in response to stimulation of a sensory organ which can be recorded by surface electrodes. Testing evoked potentials is useful in assessing the integrity of neuronal pathways both at sensory and motor levels of neural control. Early auditory evoked potentials include cochlear and brainstem auditory-evoked potentials, popularly known as electrocochleogram, and auditory brainstem response. Evoked potential audiometry is a neurophysiogical test to assess auditory pathway function in response to auditory stimuli. Auditory brainstem response mainly assesses brainstem functions and integrity. These evoked potentials are widely used for assessment of the cochlear functions, auditory nerve and the brainstem. Most common indications for auditory evoked potentials include routine newborn hearing screening for auditory pathway deficits, detecting retrocochlear pathologies, intraoperative and intensive care monitoring, frequency-related measurement of auditory sensitivity and for diagnosing some demyelinating disorders in initial stages. The current narrative review was planned to highlight auditory brainstem response recording's basic principles, uses and methods of interpretation in health and disease phases.

Hearing characteristics of infantile-onset Pompe disease after early enzyme-replacement therapy

BackgroundStudies suggest that enzyme-replacement therapy (ERT) is crucial to the survival of patients with infantile-onset Pompe disease (IOPD). Hearing impairment (HI) is one of the clinical sequelae observed in long-term survivors. However, the benefits of early ERT for hearing outcomes have not yet been reported. This study aimed to investigate the impact of early ERT on IOPD patients.MethodsThis retrospective longitudinal study recruited IOPD patients who were referred by newborn screening for confirmatory diagnosis based on our rapid diagnostic criteria and received early ERT treatment between January 1, 2010, and January 31, 2018. The hearing test battery included a tympanogram, otoacoustic emission, auditory brainstem evoked response (ABR), pure-tone audiometry or conditioned play audiometry.ResultsNineteen patients with IOPD were identified, 6 of whom had hearing impairment (HI); 1 had conductive HI, 2 had sensorineural HI (one had bilateral mild HI and one had mild HI in a single ear) and 1 had moderate mixed-type HI. Two patients failed the newborn screening test and had mild HI in the ABR. The mean age of the initial time to ERT was 11.05 ± 4.31 days, and the HI rate was 31.6% (6/19).ConclusionOur study is the largest cohort to show the characteristic hearing outcomes of IOPD patients after ERT. Early ERT within 2 weeks after birth may contribute to better hearing outcomes. Clinicians should be vigilant in testing for the hearing issues associated with IOPD and should intervene early if any HI is detected.

Gentamicin-induced sensorineural auditory loss in healthy adult horses.

BackgroundIrreversible sensorineural auditory loss has been reported in humans treated with aminoglycosides but not in horses.ObjectiveInvestigate if auditory loss occurs in horses treated using the recommended IV daily dosage of gentamicin for 7 consecutive days.AnimalsTen healthy adult horses (7‐15 years; females and males, 5 each).MethodsProspective study. Physical and neurological examinations and renal function tests were performed. Gentamicin sulfate was administered at a dosage of 6.6 mg/kg via the jugular vein on alternating sides for 7 days. Gentamicin peak and trough concentrations were measured. Horses were sedated using detomidine hydrochloride IV to perform brainstem auditory evoked responses (BAER) before the first dose, immediately after the last dose, and 30 days after the last dose. Peaks latencies, amplitudes, and amplitude ratios were recorded. Data from the second and last BAER were compared to results at baseline. Bone conduction was performed to rule out conduction disorders.ResultsSeven horses had auditory loss: complete bilateral (N = 1), complete unilateral (N = 2), and partial unilateral (N = 4). Based on physical examination and BAER results, sensorineural auditory loss was suspected. Absent bone conduction ruled out a conduction disorder and further supported sensorineural auditory loss in horses with completely absent BAER. Auditory dysfunction was reversible in 4 of 7 horses.Conclusions and Clinical ImportanceGentamicin at recommended doses may cause sensorineural auditory loss in horses that might be irreversible. Follow‐up studies are needed to investigate if other dosing protocols present a similar risk.

Continuous positive airway pressure treatment may negatively affect auditory maturation in preterm infants.

Nasal continuous positive airway pressure (CPAP) devices generate loud noise, which might harm auditory function and maturation. The function of auditory pathways can be examined by using brainstem auditory evoked potential (BAEP) and brainstem audiometry (BA) recordings. Our objective was to study whether CPAP treatment during the neonatal period is associated with abnormalities in BAEP and BA recordings. Included in this retrospective study were preterm infants (birth weight ≤1500g and/or gestational age ≤32weeks) born between 2002 and 2006 with a comprehensive clinical background and follow-up data, including the duration of CPAP treatment (n=162). BAEP and BA were recorded near the mean corrected age of one month. The following variables from BAEP and BA examinations were analysed: latencies of BAEP components I, III, V, interpeak intervals (IPI) I-V, I-III, III-V (ms), amplitude I and V (µV), amplitude ratio I/V and BA thresholds. In the adjusted analysis, a longer CPAP treatment leads to longer latencies of BAEP component III (p=0.01) and V (p=0.02) in the right ear. CPAP treatment may impair the auditory maturation and processing mediated via the dominant right ear. The hearing and neurodevelopment of the children who are treated with CPAP should be followed.