Results Of Brainstem Auditory Evoked Potentials Research Articles

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.

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.

Evaluation of central nervous system in patients with glycogen storage disease type 1a.

We aimed to evaluate structure and functions of central nervous system (CNS) in children with glycogen storage disease (GSD) type 1a. Neurological examination, psychometric tests, electroencephalography (EEG), magnetic resonance imaging (MRI), visual evoked potentials (VEP) and brainstem auditory evoked potentials (BAEP) were performed. The results were compared between patients with good and poor metabolic control and healthy children. Twenty-three patients with GSD type 1a were studied. Twelve patients were in poor metabolic control group and 11 patients in good metabolic control group. Five patients had intellectual disability, 10 had EEG abnormalities, seven had abnormal VEP and two had abnormal BAEP results. MRI was abnormal in five patients. There was significant correlation between the number of hypoglycemic attacks and MRI abnormalities. Central nervous system may be affected in GSD type 1a even in patients with normal neurologic examination. Accumulation of abnormal results in patients with poor metabolic control supports the importance of metabolic control in GSD type 1a.

Brainstem auditory evoked potentials in traffic policemen occupationally exposed to vehicular emission

Background and Aim: It is a well-known fact that traffic policemen in Delhi are exposed to immense vehicular pollution particularly at crowded intersections. These pollutants affect various systems of the body including nervous system in due course of time. Realizing these facts, we recorded absolute and inter peak latencies (IPLs) of brainstem auditory evoked potentials (BAEPs) in traffic policemen exposed to enormous vehicular emission and compared with the normal controls living in the residential areas in Delhi. Methods: Totally, 60 subjects all males and nonsmokers between 30 and 50 years of age were studied, 30 belonged to exposed group comprised of traffic policemen and 30 nonexposed controls. Their BAEPs were recorded using MEB 5200 Neuropack II plus evoked potential recorder (Nihon Kohden, Japan) and evaluation of anthropometric and neuro-psychiatric parameters was done. To compare BAEP results, Student's t -test was used. Results: Significantly prolonged absolute peak latencies I, II, III, IV, V and IPL I-III in exposed group were observed as compared to controls. Conclusion: Findings suggest prolongation of peripheral and central auditory conduction time in exposed subjects. The prolonged latencies in exposed group may be attributed to occupational exposure to vehicular emission.

Potenciales evocados auditivos del tronco cerebral y somatosensoriales en los pacientes con malformación de Chiari

Chiari malformations (CM) include a series of congenital anomalies involving the descent of the cerebellar tonsils below the foramen magnum, which may be associated with compression in the brainstem, upper spinal cord, and cranial nerves, consequently altering the responses of brainstem auditory evoked potentials (BAEP) and somatosensory evoked potentials (SSEP). However, only a small number of authors have described the indications of these tests in CM, and study groups to date have been small and heterogeneous. To review the results of BAEPs and SSEPs in published studies of patients with Chiari type 1 malformation (CM-1) or Chiari type 2 malformation (CM-2) as well as the indications of both tests in the diagnosis, treatment, and monitoring of both diseases, especially CM-1. We present a review article analyzing data from all published studies in Medline starting in 1966, located through PubMed, using combinations of the following keywords: 'Chiari malformation', 'Arnold-Chiari malformation', 'Chiari type 1 malformation', 'Arnold-Chiari type 1 malformation', 'evoked potentials', 'brainstem auditory evoked potentials' and 'somatosensory evoked potentials' as well as records of patients with CM-1 from the neurosurgery and neurophysiology departments at the Hospital Universitari Vall d'Hebron. Common findings of SSEP are a reduction in cortical amplitude from the posterior tibial nerve, a reduction or absence of cervical median nerve potential, and an increased N13-N20 interval. In BAEP, the most frequent findings are an increased I-V interval and a peripheral or cochlear auditory disturbance.

Electrophysiological study of hearing in full-term small-for-gestational-age newborns

To describe the Brainstem Auditory Evoked Potential (BAEP) results of full-term small-for-gestational-age newborns, comparing them to the results of full-term appropriate-for-gestational-age newborns, in order to verify whether the small-for-gestational-age condition is a risk indicator for retrocochlear hearing impairment. This multicentric prospective cross-sectional study assessed 86 full-term newborns - 47 small- (Study Group) and 39 appropriate-for-gestational-age (Control Group - of both genders, with ages between 2 and 12 days. Newborns with presence of transient evoked otoacoustic emissions and type A tympanometry were included in the study. Quantitative analysis was based on the mean and standard deviation of the absolute latencies of waves I, III and V and interpeak intervals I-III, III-V and I-V, for each group. For qualitative analysis, the BAEP results were classified as normal or altered by analyzing these data considering the age range of the newborn at the time of testing. In the Study Group, nine of the 18 (38%) subjects with altered BAEP results had the condition of small-for-gestational-age as the only risk factor for hearing impairments. In the Control Group, seven (18%) had altered results. Female subjects from the Study Group tended to present more central alterations. In the Control Group, the male group tended to have more alterations. Full-term children born small or appropriate for gestational age might present transitory or permanent central hearing impairments, regardless of the presence of risk indicators.

A study of gender, head circumference and BMI as a variable affecting BAEP results of late teenagers

Background : Influence of sex on brainstem auditory evoked potential (BAEP) is not well understood with few studies in India that targets young Teenagers. Aim : Our study aimed to look into gender, head circumference, and body mass index (BMI) as a factor affecting BAEPs of healthy late teenagers. Materials and Methods : BAEP responses were elicited in age-matched teenager college students using standard protocol. Results of absolute latencies and interpeak latencies (IPLs) were compared among Male and female groups and compared for significance as such and after normalizing head size and BMI and tested for significant difference, if any. Results: Latencies and IPLs of BAEP were lower in males when compared with females, but significance was found only for the later parameter. IPLs showing significant gender difference were for I-III and III-V but not I-V. When test groups with comparable head size and BMI were compared, the difference decreased with neither of the parameter being statistically significant. Conclusion: Utility of BAEP can be optimized by establishing normative data for every setup based on BMI and head circumference along with age and gender before using it as a clinical tool.

Clinical and Electrophysiological Characterization of Myokymia and Neuromyotonia in Jack Russell Terriers

Generalized myokymia and neuromyotonia (M/NM) in Jack Russell Terriers (JRTs) is related to peripheral nerve hyperexcitability syndrome in humans, a symptom complex resulting from diverse etiologies. Clinical and electrodiagnostic evaluation is used to narrow the list of possible etiological diagnoses in JRTs with M/NM. Nine healthy JRTs and 8 affected JRTs. A prospective study was conducted comparing clinical and electrophysiological characteristics in 8 JRTs affected by M/NM with 9 healthy JRT controls. All affected dogs except 1 had clinical signs typical of hereditary ataxia (HA). In 6 dogs, neuromyotonic discharges were recorded during electromyogram. Motor nerve conduction studies showed an axonal neuropathy in only 1 affected dog. Compared with controls, brainstem auditory-evoked potentials (BAEP) showed prolonged latencies (P<.05) accompanied by the disappearance of wave components in 3 dogs. Onset latencies of tibial sensory-evoked potentials (SEP) recorded at the lumbar intervertebral level were delayed in the affected group (P<.001). The BAEP and SEP results of the only neuromyotonic dog without ataxia were normal. The BAEP and spinal SEP abnormalities observed in JRTs with M/NM were associated with the presence of HA. Therefore, these electrophysiological findings presumably arise from the neurodegenerative changes characterizing HA and do not directly elucidate the pathogenesis of M/NM. An underlying neuronal ion channel dysfunction is thought to be the cause of M/NM in JRTs.

Incidence of Hypoacusia Secondary to Hyperbilirubinaemia in a Universal Neonatal Auditory Screening Programme Based on Otoacoustic Emissions and Evoked Auditory Potentials

Hyperbilirubinaemia is a neonatal risk factor that has been proved to be associated with sensorineural hearing loss. A high concentration of unconjugated bilirubin place newborn children at risk of suffering toxic effects, including hypoacusia. Review of the newborn screening results with a diagnosis of pathological hyperbilirubinaemia as part of a hearing-loss early detection protocol in the general population based on otoemissions and evoked potentials. Retrospective study of 21 590 newborn children screened between 2002 and 2006. The selection criteria for defining pathological hyperbilirubinaemia were bilirubin concentrations in excess of 14 mg/dL in pre-term infants and 20 mg/dL in full-term babies. The Universal Neonatal Hearing Screening Programme is a two-phase protocol in which all children are initially subjected to a transient otoacoustic emissions test (TOAE). Children presenting risk factors associated with auditory neuropathy were always given brainstem auditory evoked potentials (BAEP). The patients identified as having severe hyperbilirubinaemia in the neonatal period numbered 109 (0.5 %) and 96 of these (88.07 %) passed the otoacoustic emissions test at the first attempt and 13 (11.93 %) did not; 11 of the 13 children in whom the otoacoustic emissions test was repeated passed it successfully. The 2 children who failed to pass the otoacoustic emissions test has normal BAEP results; 3 (2.75 %) of the newborn infants who passed the TOAE test did not pass the BAEP. Hyperbilirubinaemia values previously considered safe may harm the hearing system and give rise to isolated problems in auditory processing without being associated with other signs of classical kernicterus. Our results show that hyperbilirubinaemia-related auditory neuropathy reveals changes over time in the audiometric outcomes.

Prevention of retrocochlear hearing loss in murine experimental allergic encephalitis with T cell receptor Vβ8-specific antibody

Experimental allergic encephalomyelitis (EAE) is an animal model of a T cell-mediated autoimmune disease, for example multiple sclerosis (MS). We demonstrated that EAE mice developed retrocochlear hearing loss and the lesion of the auditory pathway might be related to T cell receptor (TCR) Vβ8-expressing T cells. To investigate whether anti-Vβ8 antibody could prevent hearing loss, brainstem auditory evoked potentials (BAEPs) histological examinations were carried out in antibody treated and control myelin basic protein (MBP) immunized B10.PL mice. The antibody was administered just before immunization of MBP. The disease incidence and severity were significantly reduced in the mice injected with the antibody. The results of BAEPs and histological examinations indicated that depletion of Vβ8-expressing T cells causes the prevention of hearing loss as well as prevention of other neurological deficits. The development of TCR specific antibody therapy might help treat retrocochlear hearing loss in MS.

Brainstem auditory-evoked potential examinations in diabetic patients.

Brainstem auditory-evoked potential (BAEP) examinations were performed in 15 patients with long-standing type-1 diabetes mellitus (DM). Cardiovascular reflex tests were applied for assessment of autonomic neuropathy. The aim of our investigation was to compare the BAEP results of this patient group with controls and to look for a possible correlation between the alteration of the auditory brainstem function and the cardiovascular autonomic neuropathy. Analysis of the latencies (waves I, II, III and V) and the inter-peak latencies (waves I-III and I-V) of BAEPs revealed a significant difference between diabetics and healthy controls. The amplitudes of waves I, III and V were definitely lower in comparison with those of healthy controls. A positive correlation was observed between the overall autonomic score and the latencies (waves III and V) and inter-peak latencies (waves I-III and I-V). These data support the hypothesis that long-standing DM and diabetic neuropathy might be related as a cause of certain dysfunctions of the central auditory pathways.

Functional Changes of the Brainstem Triggering Diffuse 3 Hz Spike‐and‐Wave Complexes 111

Purpose: In the previous studies (1 and 11), we had disclosed 2 types of functional changc in the lower brainstem beforc and during diffuse 3 Hz spike‐and‐wave complexes (SWC) in human primary generalized epilepsy (PGE): a long‐range biphasic fluctuation and rhythmic oscillations imposing on the descending limb of the former. Both were found to precede the onset of 3 H7. SWC. The results agreed with the “centrencephalic system” hypothesis for thc generating mcchanism 01 human PGE. In this study, we furthcr investigated the time coursc of development of rhythmic oscillations during the progrcssion of 3 Hz SWC. Methods: Six paticnts with typical absence scizure (TA) werc selected for this study. Six‐channel EEGs (Cz‐AI, Cz‐A2, T3‐C3, C3‐Cz, C Z ‐C and C4‐T4; band‐pass filter, I .S Hz ‐ I .5 kHz) were recorded together with 1 channel of acoustic trigger signal (SO dB hinaurally applied clicks, 20 times/sec) and stored on a magnetic tape. Thc data were replayed and sampled (sampling frequency, 10 kHz) through a personal computer, then spontaneous 3 Hz SWC was selected for the investigation. From the onset of SWC, 24 spike components were located with a pair of 3 segments (segment, 512‐point EEG data triggered by 1 trial of acoustic signal). As the averaging area composed of 3x24 segments was shifted forward by 1 segment, a series of 9 sequential brainstem auditory evoked potentials (BAEPs) were calculated in each shift using Cz‐A I and Cz‐A2. These sequential averaging procedures were repeated as the averaging area was shifted forward by 2 cycles of SWC until the first pair of segments reached the 17‐th SWC. The EEG trends were effectively subtracted by fitting a 7‐order polynomial curve before the average. Following these procedures, functional changes of the brainstem were investigated in 9 series composed of 9 sequential tracings of BAEPs from the onset of 3 Hz SWC. The sequence of BAEPs in a series corresponded to I cycle of SWC. Amplitude and area of both wave‐I11 and wave‐V were measured then tested for the differences within a cycle of SWC by 1‐way repeated measures of ANOVA in each series among the patients. One cycle of background EEGs was also averaged by reducing the data points to correlate the results of BAEPs. Results: Wave‐111 amplitude exhibited significant oscillatory changes synchronizing with I cycle of SWC: it gradually increased during the wave component, and then abruptly decreased predicting the next spike component. Both wave‐V parameters showed no significant changes. The oscillatory changes of wave‐I11 amplitude lasted from the onset to the middle stage of 3 Hz SWC development, They temporarily disappeared as the seizure progressed and then reappeared while background EEGs continued to exhibit 3 HZ SWC. Therefore, they were not considered as secondary phenomena generated by the cortical SWC. The phase of the reappearing oscillation was different from that of the preceding oscillations: the phase delayed so as to maintain its excitability during the spike component. Conclusion: The results confirm the previous conclusion that functional oscillations in the lower brainstem act pacemaker for cortical SWC, however they occur only during the early stage of SWC development. The results further suggest that the lower brainstem participates in the cessation of the seizure by changing the oscillatory phase against the cortical SWC.

Ataxia-telangiectasia: somatosensory, brainstem auditory and motor evoked potentials in six patients.

Six patients with ataxia-telangiectasia were given neurophysiological examinations. The patients had progressive sensorimotor axonal neuropathy that had begun at about age eight years. Brainstem auditory evoked potentials (BAEPs) showed central alternations in two of four cases. Somatosensory (BAEPs) and motor evoked potentials (MEPs) were altered in four of five cases. In the advanced stage of the disease the neurophysiological findings, except BAEPs and MEPs, resembled those in Friedreich's ataxia. MEP and BAEP results may therefore be useful for differential diagnosis.