Brainstem Auditory Evoked Potential Test Research Articles

Brainstem auditory evoked potential wave V latency-intensity function in normal Dalmatian and Beagle puppies.

This study investigated whether Dalmatian puppies with normal hearing bilaterally had the same click-evoked brainstem auditory potential characteristics as age-matched dogs of another breed. Short-latency brainstem auditory potentials evoked by condensation and rarefaction clicks were recorded in 23 1.5- to 2-month-old Dalmatian puppies with normal hearing bilaterally by a qualitative brainstem auditory evoked potential test and in 16 Beagle dogs of the same age. For each stimulus intensity, from 90 dB normal hearing level down to the wave V threshold, the sum of the potentials evoked by the 2 kinds of stimuli were added, giving an equivalent to the alternate click polarity stimulation. The slope of the L segment of the wave V latency-intensity curve was steeper in Dalmatian (-40 +/- 10 micros/dB) than in Beagles (-28 +/- 5 micros/dB, P < .001) puppies. The hearing threshold was lower in the Beagle puppies (P < .05). These results suggest that interbreed differences may exist at the level of cochlear function in this age class. The wave V latency and wave V-wave I latencies differences at high stimulus intensity were different between the groups of puppies (4.3 +/- 0.2 and 2.5 +/- 0.2 milliseconds, respectively, for Beagles; and 4.1 +/- 0.2 and 2.3 +/- 0.2 milliseconds for Dalmatians, P < .05). A different maturation speed of the neural pathways is one possible explanation of this observation.

Bilateral Reversible Deafness after Surgery for Unilateral Epidermoid Tumor: An Unusual Complication: Case Report

We present an unusual complication of bilateral hearing loss after surgery for unilateral epidermoid tumor situated at the right pontocerebellar junction. The neurosurgeon must know the possible causes of this catastrophic complication and should take every possible measure to avoid it. A 43-year-old male patient presented with progressive hearing loss in the right ear. A radiological examination demonstrated a mass lesion at the right pontocerebellar junction. A pure tone audiogram revealed sensorineural hearing impairment of the right ear. A brainstem auditory evoked potential test confirmed this with reduced amplitudes and a prolonged I-V interval. The patient was operated on via a right paramedian suboccipital craniectomy. The tumor was completely excised, and all of the cranial nerves were preserved during the operation. Postoperatively, the patient developed total bilateral hearing loss, which improved significantly over time. Controlled cerebrospinal fluid drainage during exposure and tumor excision may reduce the possibility of shift and traction on the neural structures and help to prevent ischemic injury. Frequent irrigation of the surgical field and minimizing the spilling of the tumor contents may reduce the risk of chemical irritation. The use of corticosteroids may also help during the postoperative period.

Brainstem Auditory Evoked Potential Wave V Latency‐Intensity Function in Normal Dalmatian and Beagle Puppies

This study investigated whether Dalmatian puppies with normal hearing bilaterally had the same click‐evoked brainstem auditory potential characteristics as age‐matched dogs of another breed. Short‐latency brainstem auditory potentials evoked by condensation and rarefaction clicks were recorded in 23 1.5‐ to 2‐month‐old Dalmatian puppies with normal hearing bilaterally by a qualitative brainstem auditory evoked potential test and in 16 Beagle dogs of the same age. For each stimulus intensity, from 90 dB normal hearing level down to the wave V threshold, the sum of the potentials evoked by the 2 kinds of stimuli were added, giving an equivalent to the alternate click polarity stimulation. The slope of the L segment of the wave V latency‐intensity curve was steeper in Dalmatian (—40 ± 10 μs/dB) than in Beagles (—28 ± 5 μs/dB,P&lt; .001) puppies. The hearing threshold was lower in the Beagle puppies (P&lt; .05). These results suggest that interbreed differences may exist at the level of cochlear function in this age class. The wave V latency and wave V‐wave I latencies differences at high stimulus intensity were different between the groups of puppies (4.3 ± 0.2 and 2.5 ± 0.2 miiliseconds, respectively, for Beagles; and 4.1 ± 0.2 and 2.3 ± 0.2 milliseconds for Dalmatians,P&lt; .05). A different maturation speed of the neural pathways is one possible explanation of this observation.

Utility of brainstem auditory evoked potentials in children with spastic cerebral palsy

In a retrospective study of 75 children with spastic cerebral palsy (CP), brainstem auditory evoked potentials (BAEP) were recorded and subsequently correlated with birthweight, gestational age, aetiology and type of CP, neuroradiological findings, additional impairments and disabilities (including the inability to walk independently). Seventeen patients (22.7%) had abnormal BAEP recordings. Thirteen of these 17 patients (76.5%) had spastic tetraplegia, 16 patients (94.1%) were full-term infants, 12 patients (70.6%) had myoskeletal problems, 9 (52.9%) had epilepsy, 16 (94.1%) had visual impairment, 13 patients (76.5%) were unable to walk independently, while all 17 patients (100%) had speech impairment and mental retardation. The aetiology of CP was prenatal in 2 of these 17 patients (11.8%) and perinatal in 15 patients (88.2%). Thirteen patients (76.5%) had cortical atrophy determined by either computed tomography or magnetic resonance imaging, two patients (11.8%) had an infarct picture and two patients (11.8%) had maldevelopment of the central nervous system. There was a definite statistically significant association between abnormal BAEP recordings and full-term delivery, perinatal aetiology of CP, spastic tetraplegia, speech, visual and myoskeletal impairments, epilepsy, mental retardation, inability to walk independently and cortical atrophy on neuroimaging (p < 0.001). We conclude that abnormal BAEP recordings in children with spastic CP are indicative of poor prognosis and associated with a "multihandicap state". BAEP testing should be incorporated into the diagnostic plan of all children with spastic CP newly referred to neurodevelopmental centres.

Auditory screening in high-risk pre-term and full-term neonates using transient evoked otoacoustic emissions and brainstem auditory evoked potentials

The present report concerns a 3 year, 8 month hearing screening in 1531 high-risk neonates by means of two successive transient evoked otoacoustic emission (TEOAE) recordings followed, in cases of suspected hearing loss, by brainstem auditory evoked potential (BAEP) recording and otolaryngology (ORL) consultation. After TEOAE 1 and 2 and BAEP testing, 1361 infants (88.9%) were declared normal, and 170 (11.1%) suspected of hearing loss. Of these 170, 58 showed bilateral and 26 unilateral impairment. Definite hearing loss on ORL consultation was diagnosed in 14 infants (0.9% of the screened population as a whole); 22 are still being followed, while 86 (5.6%) failed to consult for diagnosis. The mean age on diagnosis of definite hearing loss was 9.9±4.9 (range 4–20) months. Several auditory function risk factors proved more frequent in deaf than in normal children. Our results show that early hearing loss screening in at-risk neonates needs to be pursued.

Sensitivity and specificity of the neonatal brain-stem auditory evoked potential for hearing and language deficits in survivors of extracorporeal membrane oxygenation

Objective: We determined the sensitivity and specificity of neonatal brain-stem auditory evoked potentials (BAEP) as markers for subsequent hearing impairment and for developmental problems found later in infancy and childhood. Methods: BAEP studies were performed before discharge in infants treated with extracorporeal membrane oxygenation (ECMO), and two specific abnormalities were analyzed: elevated threshold and delayed central auditory conduction. Behavioral audiometry was repeated during periodic follow-up until reliable responses were obtained for all frequencies, and standardized developmental testing was also conducted. The sensitivity and specificity of an elevated threshold on the neonatal BAEP for detecting subsequent hearing loss, and the relationship of any neonatal BAEP abnormality to language or developmental disorders in infancy, were calculated. Results: Test results for 46 ECMO-treated infants (57.5%) were normal, and those for 34 infants (42.5%) were abnormal, with either elevated wave V threshold, prolonged wave I-V interval, or both on neonatal BAEP recordings. Most significantly, 7 (58%) of the 12 children with subsequent sensorineural hearing loss had left the hospital after showing normal results on threshold tests. There was no significant difference in the frequency of hearing loss between subjects with abnormal (5/21, or 24%) and those with normal BAEP thresholds (7/59, or 12%; Fisher Exact Test, p = 0.28). Therefore the sensitivity of neonatal BAEP testing for predicting subsequent hearing loss was only 42%. Neonatal BAEP specificity for excluding subsequent hearing loss was 76%. In contrast, on language development testing, 19 children demonstrated receptive language delay. Of these children, 12 (63%) had abnormal neonatal BAEP recordings and 7 (37%) had a normal BAEP threshold, normal central auditory conduction test results, or both ( p = 0.04). Conclusions: Neonatal BAEP threshold recordings were of limited value for predicting subsequent hearing loss common in ECMO-treated survivors. However, an abnormal neonatal BAEP significantly increased the probability of finding a receptive language delay during early childhood, even in those with subsequently normal audiometry findings. Because neonatal ECMO is associated with a high risk of hearing and receptive language disorders, parents should be counseled that audiologic and developmental follow-up evaluations in surviving children are essential regardless of the results of neonatal BAEP testing. (J Pediatr 1997;131:233-9)

When is Isolated Vertigo a Harbinger of Stroke?

Isolated vertigo is usually a distressing though benign clinical entity. Recently, however, it has been recognized that in a subset of patients isolated vertigo may be a harbinger of vertebrobasilar stroke. Recognition of this "at risk" subgroup may be difficult. Brainstem auditory evoked potentials (BAEPs) are usually normal in patients with vertigo from labyrinthine disease. We describe a patient with isolated vertigo, in whom BAEPs were abnormal, and who subsequently developed an anterior inferior cerebellar artery territory infarct. BAEP testing might lead to early recognition of those patients at risk for catastrophic stroke, and prompt appropriate investigation and treatment to prevent this outcome.

Bacterial Meningitis and Hearing Impairment: A Prospective Study

The purpose of this study is to demonstrate the incidence and the pattern of post-meningitis hearing impairment. A prospective study of 68 meningitis patients was performed. The patients' hearing was evaluated immediately following acute illness and periodically checked for two years. The incidences of the initial sensorineural and conductive deafness were 26.4% and 20.6%, respectively. Two patients (3%) suffered from mixed deafness. No consistent audiometric pattern was found in the cases of sensorineural hearing loss. Serial hearing evaluations demonstrated complete recovery of all cases of conductive hearing loss with only a slight improvement in the low tones noted in one patient with sensorineural hearing loss. No late development of sensorineural loss has occurred.

Brainstem auditory evoked potentials in very-low-birth-weight neonates with intracranial hemorrhage

A study was conducted in very-low-birth-weight (VLBW) neonates to correlate structural damage to the central nervous system due to intracranial hemorrhage (ICH) with electrophysiological function of the lower auditory system as measured by brainstem auditory evoked potentials (BAEP). BAEP testing of 61 VLBW neonates was completed at 36 weeks conceptional age. BAEP Wave III and V latencies significantly increased with increasing severity of ICH. Although significant at conventional levels (P < 0.05), these correlations were of modest size. Furthermore, after adjusting for the effects of birthweight, hypoxia, lowest pH and associated pCO 2 the correlation between ICH and BAEP was reduced in magnitude and no longer significant. Thus, there is little evidence that ICH shortly after birth affected functioning of the auditory brainstem pathways in VLBW neonates at 36 weeks conceptional age.

THE NEONATAL BAEP AS A PREDICTOR OF NEURO-DEVELOPMENT

Brainstem Auditory Evoked Potentials (BAEP) were recorded in 24 high risk neonates in the intensive care unit. The following risk factors were present alone or in combination in all subjects: birth-weight below 1500 gm, gestational age below 33 weeks, intracranial hemorrhage, birth asphyxia, respiratory distress syndrome, sepsis and seizures. The infants tested ranged in gestational age from 25-44 weeks. The BAEP testing was performed between 37 and 42 weeks post-conceptional age, using monoaural 70 dBHL rarefaction clicks presented at a rate of 11/sec. Serial recordings were obtained in all preterm infants. Wave I and V peak latencies and wave I-V interwave intervals were measured and compared to a group of 40 low-risk neonates. Abnormalities of one or more BAEP parameters were found in 10 high-risk neonates; at 18 to 24 months Bayley Scale scores were more than one standard deviation below the mean standard score for age in 6 of these infants, two of whom had cerebral palsy. However, 5 of 14 infants who had normal BAEP latencies in the newborn period were found at 18 to 24 months to have Bayley Scale scores more than one standard deivation below the mean for age. These findings indicate a lack of correlation between the BAEP latencies and neurodevelopmental outcome. Therefore, in contrast to results reported by others, we found no correlation between BAEP latencies in the neonatal period and neurodevelopmental outcome at age 18 to 24 months.

Early abnormalities of brainstem auditory evoked potentials in Friedreich's ataxia: evidence of primary brainstem dysfunction.

We studied five children with classic Friedreich's ataxia, using an audiologic test battery to determine the primary site of auditory dysfunction. None of the children had any hearing complaints, and all were tested soon after onset of symptoms. The audiologic test battery consisted of brainstem auditory evoked potential test, tympanometry, and acoustic reflex measurements. The results indicated that the brainstem was the primary site of auditory dysfunction.

Abnormal brain stem potentials in infants with threatened sudden infant death syndrome.

Fifteen infants at risk for sudden infant death syndrome by clinical criteria were tested using brain stem auditory evoked potential (BAEP) techniques. All infants demonstrated abnormalities on two or more of the seven criteria employed to assess results. The data indicate that BAEP testing may play a significant role in the identification and monitoring of these children.

Brainstem auditory evoked potentials for detection of retrocochlear pathology.

Since May 1976 the techniques of brainstem auditory evoked potential (BAEP) testing have been used as a clinical tool in evaluating patients with neurotologic disease in the Department of Otolaryngology and Communicative Disorders at the Cleveland Clinic Foundation. A total of 676 patients was tested using this technique and included patients with primary otologic complaints as well as patients with neurologic disorders. Patients were evaluated with suspected multiple sclerosis, for threshold assessment, children at risk for possible sudden infant death syndrome, brainstem gliomas, systemic neurologic or metabolic disorders, and the final group of 408 patients or 60% were tested for suspected eighth nerve lesions. In the group of patients studied for detection of an eighth nerve lesion, the BAEP test was extremely useful if the result was found to be normal, for at the time of this report, no patient with an eighth nerve lesion, such as an acoustic neuroma, had a normal BAEP test result. However, abnormal results in the BAEP test were found in approximately 34% of patients who underwent Pantopaque® myelography for definitive detection of an eighth nerve lesion in which the myelogram was normal. This unusually high false-positive rate is thought to be the result of testing a different patient population than those that have previously been reported in the literature. There still may be some eighth nerve pathology present; however, the results of the BAEP test which have been suggestive of an eighth nerve lesion remain unexplained at this time. The BAEP test is a very important part of the evaluation of patients with neurotologic disease; however, it is not sufficiently understood to eliminate the need for a complete work-up in patients suspected to have a retrocochlear lesion.