Normal Brainstem Auditory Evoked Potentials Research Articles

Self-Perception of Hearing Difficulties and Quality of Life in Individuals with Hearing Loss.

Objectives: To characterize the results of the Short Form Health Survey-36 (SF-36), Abbreviated Profile of Hearing Aid Benefit (APHAB), and the Hearing Handicap Inventory for Adults (HHIA) questionnaires in individuals with mild to moderate sensorineural hearing loss and compare them with brainstem auditory evoked potentials (BAEPs). Methods: There were 26 individuals with mild to moderate bilateral symmetrical sensorineural hearing loss who participated in the study. They were aged between 13 and 59 years old, right-hand preference, of both sexes, and were assigned to one of two groups according to the result of a BAEP test: normal (n = 16) or altered (n = 10). All subjects underwent a brief, cognitive screening battery and answered the SF-36, APHAB, and HHIA self-assessment questionnaires. For analysis of results, descriptive measures and inferential analysis were used. Results: On the SF-36 questionnaire, scores below 80 points were found in both groups, signifying minimal impact in the domains of pain, general health, vitality, and mental health compared to the other domains. The results of the APHAB questionnaire showed worse scores on the environmental noise subscale, and evaluation with the HHIA revealed a perception of severe restriction in participation in daily life activities. In a comparison between the groups, normal or abnormal BAEPs, no significant differences were found for any of the questionnaires. Conclusions: The results of the self-assessment questionnaires indicate that individuals with hearing loss can experience reduced quality of life, with limitations and restrictions for participation in daily living. The use of BAEPs as a criterion for dividing the groups was not effective in isolating the central component in the results of the self-assessment questionnaires.

Multimodal Evoked Potential Profiles in Woodhouse-Sakati Syndrome.

Woodhouse-Sakati syndrome is a rare autosomal recessive syndrome caused by homozygous mutations in the DCAF17 gene, characterized by marked neurologic and endocrine manifestations in the setting of brain iron accumulation and white matter lesions on neuroimaging. Here, we report electrophysiologic profiles in Woodhouse-Sakati syndrome and their possible value in understanding disease pathophysiology and phenotypic variability. Thirteen genetically confirmed Woodhouse-Sakati syndrome patients were evaluated via different evoked potential (EP) modalities, including brainstem auditory EPs, pattern reversal visual EPs, and somatosensory EPs to tibial and/or median nerves. All EP modalities showed variable abnormalities. Pattern reversal visual EPs were recorded in all patients, with nine patients exhibiting abnormal results. From those, seven patients showed prolonged P100 latencies after stimulation of right and left eyes for each in turn. Two patients showed P100 latency abnormality after single eye stimulation recorded from midoccipital electrode. Median somatosensory EPs were recorded in 10 patients, with 6 patients having a prolonged cortical N19 response. Tibial somatosensory EP was performed for 11 patients, and 8 patients showed abnormal results where P37 cortical response was absent or prolonged, whereas peripheral potentials at the popliteal fossa were normal. Brainstem auditory EPs were abnormal only in two patients, with prolonged wave III and V latencies. Five patients with hearing impairment presented with normal brainstem auditory EP results. Multiple EP abnormalities are observed in Woodhouse-Sakati syndrome patients, mainly in pattern reversal visual EPs and somatosensory EPs. These findings indicate potential myelin dysfunction that has a role in the underlying pathophysiology, disease course, and phenotypic variability.

Study of age-influences on brainstem auditory evoked potentials in healthy adults

Background and objectives: Brainstem auditory evoked potentials (BAEPs) have widespread clinical utility . BAEP responses exhibit a normal variability due to various non-pathologic factors and age is one of the variables suggested to have considerable influence on normal BAEP responses. Aging changes in the auditory system may significantly influence the interpretation of the auditory brainstem responses in comparison with younger adults. Hence, the study was planned to evaluate the influence of age on absolute and interpeak latencies in healthy subjects in the age-group of 18-70 years. Methods: The test was conducted on 150 healthy adults in the age-group of 18-70 years (75 males and 75 females). BAEP latencies were compared in different age groups by one way ANOVA. Correlations of latencies with age were performed using Pearson correlation coefficient. P value 48 years of age. Conclusion: Age contributes to the normal variations in BAEP latencies. Acquisition of a normative data for different age-groups can improve the clinical utility of the test. The pattern of interpeak latency changes with age in the present study indicates a greater possibility of involvement of peripheral auditory functions in the elderly subjects.

Classification of Brainstem Auditory Evoked Potentials Using Artificial Neural Network Based on Time and Frequency Domain Features

This article presents a novel technique of automated classification of brainstem auditory evoked potentials (BAEPs). Brainstem auditory evoked potentials are the evoked potentials used to measure the brain activity that occur in response to the auditory stimulus to the ear and to record the response by placing electrodes on the surface of the scalp. Brainstem auditory evoked potentials reflect neuronal activity in the auditory nerve pathway from the cochlea to the auditory cortex and are used in the diagnosis of neurological diseases leading to hearing loss. In the proposed automated system, the features of BAEPs are extracted in time domain based on latency, and in frequency domain, using fast Fourier transform and discrete wavelet transform. The features extracted from BAEPs are used as variables to build a feed-forward multilayer perceptron, an artificial neural network model for the classification of BAEPs. The stratified 10-fold cross-validation technique is used in training and testing the model to estimate the performance of the system. The combined time and frequency domain features along with physiological parameters as input to artificial neural network resulted in a very good average accuracy of 90.74% in classifying the normal and abnormal BAEP signals.

Clinical Value of Brainstem Auditory Evoked Potential in the Diagnosis of Vertebrobasilar Ischemia

Objective: The objective of this study was to explore the clinical value of brainstem auditory evoked potential (BAEP) in the diagnosis of vertebrobasilar ischemia (VBI). Methods: The subjects were divided into the 2 following groups: an observation group of 300 VBI patients and a control group of 100 normal healthy volunteers. BAEP examination was carried out in both groups, and then the results were analyzed and compared. Results: BAEP abnormalities were observed in 59% (177 out of 300) of the patients in the observation group: brainstem type 64.4% (114 cases), inner-ear type 7.4% (13 cases), and mixed type 28.2% (50 cases). In the control group, abnormalities were observed in only 9% (9 cases): inner-ear type 66.7% (6 cases) and mixed type 33.3% (3 cases). There was a statistically significant difference between the 2 groups in their total abnormality rates (p < 0.05). After the neck twisting test, the BAEP abnormality rate of the observation group rose to 85% (255 cases) and was significantly different from that of normal BAEP (p < 0.05). Conclusion: BAEP is an easy but effective auxiliary means for the noninvasive examination of VBI with a high positive rate, thus providing objective evidence for the diagnosis of VBI that may be useful in future clinical application.

Albumin administration protects against bilirubin‐induced auditory brainstem dysfunction in Gunn rat pups

Free bilirubin (Bf), the unbound fraction of unconjugated bilirubin (UCB), can induce neurotoxicity, including impairment of the auditory system, which can be assessed by brainstem auditory evoked potentials (BAEPs). We hypothesized that albumin might reduce the risk of neurotoxicity by decreasing Bf and its translocation into the brain. To determine the effects of albumin on BAEPs and brain bilirubin content in two Gunn rat pup models of acute hyperbilirubinemia. We used Gunn rat pups, which have a deficiency of the bilirubin-conjugating enzyme UGT1A1. We induced haemolysis by injection of phenylhydrazine (phz) into 14-days old pups. Subsequently, pups were treated with either i.p. human serum albumin (HSA; 2.5 g/kg; n = 8) or saline (control, n = 8). We induced acute neurotoxicity by injecting 16-days old pups with sulphadimethoxine (sulpha) and treated them with either HSA (n = 9) or saline (control, n = 10). To assess bilirubin neurotoxicity, we used the validated BAEP method and compared relevant parameters; i.e. peak latency values and interwave interval (IWI) between peak I and peak II, a marker of acute neurotoxicity. Phz and sulpha significantly increased IWI I-II by 26% and 29% (P < 0.05) in the haemolysis and the displacement model, respectively. Albumin completely prevented the increase of IWI I-II in either model. The beneficial effect of albumin in the displacement-model by means of normal BAEPs was in line with less bilirubin in the brain (NS). Interestingly, in the haemolysis model the accumulation of total bilirubin in the brain was unaltered, and BAEPs still appeared normal. This might advocate for a role of brain Bf which was calculated and showed that albumin treatment non-significantly reduces Bf concentrations in brain, compared with saline treatment. Albumin treatment is neuroprotective in acute hyperbilirubinemia in Gunn rat pups. Our present results underline the importance of functional diagnostic test of neurotoxicity above biochemical concentrations.

Fremkalt respons-undersøkelser i klinisk diagnostikk

Evoked potentials are used to detect conduction disturbances in the central nervous system. This paper provides an overview of the areas in which evoked potentials are used in clinical neurophysiological diagnostics, with the emphasis on coma and demyelinating disease. The article is based on a literature search in PubMed and the authors' long experience of neurological and neurophysiological diagnostics. Somatosensory evoked potential (SEP) can be a reliable predictor of failure to regain consciousness as early as 24 hours after anoxic coma has occurred. If coma is caused by a brain trauma, cerebrovascular episode or other neurological disease, information about which sensory brainstem pathways are damaged can be obtained from somatosensory evoked potentials and brainstem auditory evoked potentials (BAEP), which can also be useful for planning rehabilitation. Normal SEP and BAEP findings in cases of coma caused by trauma are associated with a favourable prognosis. Visually evoked potential (VEP) can often reveal signs of a history of optic neuritis. SEP and BAEP can also reveal subclinical lesions in the central nervous system and be a supplementary diagnostic test for multiple sclerosis. The clinical value of SEP and BAEP is high in coma cases. Evoked potentials are also important in intraoperative monitoring. The clinical value of VEP is high when a history of optic neuritis is a deciding factor for a multiple sclerosis diagnosis. Some selected patients who are being assessed for demyelinating disease will benefit from a full EP study.

Glasgow Coma Scale, Brain Computerized Tomography and Neurophysiological Methods as Prognostic Factors of Pediatric Coma

Background and objectives: Coma is characterized by the total absence of both arousal and awareness. The outcome of coma depends on the etiology, depth and duration of impaired consciousness. It is likely that brain electrical function monitoring will play an increasingly important role in evaluating prognosis of coma in children. Aim: To compare the predictive values of clinical examinations combined with the recordings of Electroencephalography (EEG) and Brainstem Auditory-Evoked Potentials (BAEP) and computed tomography (CT) of the brain in the evaluation of coma outcome in children. Methods: Twenty children with coma aged 3-14 years were included in the study and subjected to: full history, clinical, neurological and otological examination. Medical investigations for coma, EEG, CT brain and auditory brainstem evoked potential (BAEP) measurements were performed for all patients. They were subdivided into 2 groups: group 1 included 8 patients with surgical causes of coma, group 2 include 12 patients with medical causes of coma. Results: There was younger age, lower Glasgow Coma Scale (GCS) and more significant incidence of unfavourable outcome (death, disability) in patients of surgical coma (group 1). A significant difference between both groups was observed regarding the presence of brain edema and intracranial hemorrhage (100% in group 1) while normally visualized basal cisterns were significantly more in group (2) (p=0.02). Favourable outcome was strongly related to normally visualize basal cisterns in CT brain (p=0.002), normal/ borderline EEG activity (p=0.03) and normal BAEP waves (p=0.009). Disability was significantly related to slow activity waves (p=0.015) and diffuse high voltage EEG discharges (0.009). While mortality was significantly related to the presence of intracranial bleeding in CT brain (p=0.02), silence EEG waves (p=0.005) and absent BAEP waves (0.012). Conclusion: EEG and Auditory brainstem response are valuable as prognostic predictors of pediatric coma either due to medical or surgical causes. The Glasgow Coma Scale (GCS) has several important limitations as a predictor of survival in the general critically ill population while CT brain is mostly important for diagnostic rather than prognostic factor in comatosed children.

Changes and significance of serum prealbumin, bilirubin/albumin ratio and BAEP in early neonatal hyperbilirubinemia

Objective To evaluate the significance of serum prealbumin, bilirubin/albumin( B/A )ratio and brainstem auditory evoked potential (BAEP)for early predicting the bilirubinic neurotoxicity caused by early neonatal hyperbilirubinemia. Methods According to the gestational age, birth weight and the intervention criterion of neonatal jaundice, 94 neonates (newborn infants with a age of 1-7days) with hyperbilirubinemia were divided into two groups, one was term neonates with normal BAEP, the other was term neonates with abnormal BAEP. We detected their serum levels of total bilirubine, prealbumin, BAEP and calculated B/A ratio. Result The prealbumin levels was significantly lower and B/A ratio was higher in group of abnormal BAEP than those of control group ( P 0. 05 ). In group of abnormal BAEP , there was a negative correlation between the level of serum prealbumin and the B/A ratio (r = -0. 637, P <0. 01 ). Conclution Prealbumin may be a sensitive indicator for early predicting bilirubinic toxicity like B/A ratio and BAEP. Key words: Hyperbilirubinemia; Prealbumin; Bilirubinic neurotoxicity; Brainstem auditory evoked potential; Early neonate

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.

EVALUATION OF BRAINSTEM AUDITORY POTENTIAL IN BRUCELLOSIS PATIENTS WITH AND WITHOUT NEUROLOGICAL INVOLVEMENT

This study investigated the changes in brainstem auditory evoked potentials (BAEPs) in acute phase of brucellosis. Twenty-two patients with brucellosis without neurologic involvement and seven patients with neurobrucellosis were included. BAEPs were evaluated before treatment. No patient had a symptom of hearing loss. Patients who had neurologic involvement did not show any abnormalities in their BAEPs recording. This study suggests that patients with brucellosis who are in the acute phase of the disease with or without neurological involvement may have normal BAEPs. BAEPs do not seem to be a sensitive method for central nervous system involvement of brucella patients in the acute phase of the disease.

Agyria-pachygyria: clinical, neuroimaging, and neurophysiologic correlations

Agyria-pachygyria complex is a disorder of neuronal migration and organization. Patients suffer either motor or intellectual retardation. We report our experiences of 10 patients with agyria-pachygyria complex and evaluate their clinical features, electroencephalography, and evoked potentials. Of nine electroencephalography examinations, five patients demonstrated characteristically high-amplitude fast activity. One of nine patients had an abnormal brainstem auditory-evoked potential. Three of seven patients had abnormal goggled visual-evoked potential. Six patients received somatosensory-evoked potential examinations, and five of these were abnormal, including four with prolonged central conduction times. Of the 10 patients, eight survived with variable intellectual and motor retardation; two died of sepsis. Patients with grades 1-4 agyria-pachygyria had high incidences of somatosensory-evoked potential abnormalities and also suffered worse neurologic outcomes. Normal brainstem auditory-evoked potential but abnormal cortical somatosensory-evoked potential components and prolonged central conduction time in these patients indicate that agyria-pachygyria is a supratentorial disease. We conclude that somatosensory-evoked potential examination is supplemental to neuroimaging in predicting the neurologic prognosis of patients with agyria-pachygyria.

Does wave VI of BAEP pertain to the prognosis of coma?

Objectives – The significance of brainstem auditory evoked potential (BAEP) wave VI for the outcome of comatose patients was assessed and compared to the prognostic impact of median nerve evoked somatosensory potential (MSEP) recording. Patients and methods – One hundred sixteen patients in a comatose state due to traumatic brain injury ( n = 57) and to intracerebral hemorrhage or tumours ( n = 59) were investigated prospectively. Outcome was assessed 3 months after the onset of coma using Glasgow Outcome Score (GOS). Standard BAEP and MSEP recordings were obtained within 24 h after coma onset. The frequency of findings was correlated with outcome by means of non-parametric statistical analysis. Additionally, 27 healthy volunteers were studied to confirm the constant presence of wave VI in normal BAEP. Results – In healthy controls, wave VI was present in 53/54 ears stimulated. Outcome correlation analysis revealed a significantly ( p < 0.01) higher frequency of abnormal wave VI in patients with unfavourable outcome (GOS 1-3) irrespective of the underlying pathology. Similarly, abnormal MSEP findings were significantly more frequent in this outcome group. Diagnostic sensitivity for an unfavourable outcome was low for both parameters, whereas specificity and positive predictive value of abnormal wave VI as well as of abnormal MSEP were equally high. Conclusion – Abnormal BAEP wave VI bears prognostic information in comatose patients.

Brainstem auditory-evoked potential evaluation in children with meningitis

Brainstem auditory-evoked potential (BAEP) was performed on 101 children with meningitis to assess the incidence of hearing impairment. Fifty-two (51.5%) children had bacterial meningitis, six (5.9%) had viral meningitis, and 43 (42.6%) had aseptic meningitis. Fifty-one (50.5%) patients were assessed before discharge and 50 (49.5%) 9 days to 17 months later (mean = 4 months). BAEP impairment was found in 28 (27.7%) of 101 patients; 24 had sensorineural and four had conductive type of hearing loss, and 17 (60.7%) had unilateral and 11 (39.3%) had bilateral impairment. Hearing threshold was elevated in 22 (21.8%) patients, and the other six had increased latency and interpeak latencies with normal threshold. Frequency of BAEP impairment or hearing loss associated with bacterial meningitis was 34.6% and 30.8%, respectively; frequency associated with aseptic meningitis was 20.9% and 13.9%, respectively. One child with viral meningitis (coxsackie virus) had mild BAEP impairment. Most of the BAEP impairment in the bacterial meningitis group was associated with H. influenzae. Prospective BAEP study was performed in 20 patients randomly at 0.3 to 18 months to assess hearing status after antibiotic treatment, 10 with normal and 10 with abnormal BAEP. All the initially normal BAEP patients remained normal. Of the 10 patients with abnormal BAEP results initially, four returned to normal, two improved, three remained unchanged, and one deteriorated. The incidence of hearing loss after bacterial and aseptic meningitis is high. BAEP is useful to screen for possible hearing loss in children with meningitis, and follow-up BAEP is necessary for those patients with initially abnormal BAEP.

Multimodality evoked potentials as a prognostic tool in term asphyxiated newborns

Hypoxic-ischemic (HI) events may cause permanent brain damage, and it is difficult to predict the long-term neurological outcome of survivors. Multimodality evoked potentials (MEPs), using flash visual (fVEPs), somatosensory (SEPs), and brain-stem auditory evoked potentials (BAEPs) may assess the cerebral function in term neonates. MEPs were recorded in 40 hypoxic-ischemic term or near-term neonates during the first week of life in order to predict the neurological outcome. A 3 point grading system registered either mild, moderate, or severe abnormalities. At 24 months of corrected age, the infants were assessed with a blind protocol to determine neurological development. Grade 0 fVEPs and SEPs were associated with a normal neurological status with 100% ( P<0.001) of the infants. Abnormal SEPs or total grade (VEPs+SEPs)>I were not associated with normal outcomes ( P<0.0001). Normal BAEPs did not predict a normal outcome, but severely abnormal BAEPs did predict an abnormal outcome. A significant correlation was found between EP (VEPs+SEPs) grade ( r=0.9, P<0.0001), Sarnat stage ( r=0.6, P<0.001), and clinical outcome. This study confirmed that both fVEPs and SEPs are more accurate as prognostic indicators for term neonates. EPs (VEPs+SEPs) also are more accurate in predicting the ultimate neurological outcome compared with the Sarnat scoring.

Intérêt diagnostique des potentiels évoqués auditifs de latence moyenne (PEALM) dans la sclérose en plaques

This study was aimed at assessing the interest of middle latency auditory evoked potentials (MLAEP) recordings in multiple sclerosis (MS). Brainstem auditory evoked potentials (BAEP) and MLAEP were recorded in 40 control subjects and 65 patients who had MS according to Poser's criteria. Na and Pa latencies were significantly delayed in the MS group. These abnormalities were detected in 60% of the patients. In 26% of the cases with normal BAEP, abnormalities of MLAEP were present. In 71% of the patients abnormalities of both BAEP and MLAEP were observed. These results suggest the ability of MLAEP recordings to detect lesions of the auditory pathways rostral to the pons and show the value of their combined recordings in MS patients.

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)

Brainstem auditory and visual evoked potentials in infants with myelomeningocele

Brainstem auditory evoked potentials (BAEPs) and visual evoked potentials WEN were recorded in 47 infants with myelomeningocele to determine if the evoked potentials reflected the early neurological status, and if they had prognostic value as to the children's neurological outcome. The infants were tested between 1 day and 3 months of age (mean 24 days), while still in hospital after the myelomeningocele repair. Outcome was assessed at a mean of 2 years of age. Normal BAEPs were found in 41% and normal VEPs in 62% of the patients. BAEPs were abnormal in all infants studied who had symptomatic Arnold-Chiari (AC) malformation ( n = 9); VEPs were abnormal in only 55% of symptomatic infants. Of the infants who did not have symptomatic AC malformation, 53% had normal BAEPs, 69% had normal VEPs. Of the patients with normal BAEPs, 81% had normal cerebral function on follow-up. Of the patients with abnormal BAEPs, 87% had central neurological abnormalities on follow-up. Of the patients with normal VEPs, 63% were normal on follow-up; of the patients with abnormal VEPs, 71% were abnormal on follow-up. Thus, the VEPs studied early in the neonatal course do not appear to be sufficiently sensitive to be valuable prognostically in these infants. However, the BAEPs were consistently abnormal in symptomatic AC malformation and showed a positive predictive value of 88% and an accuracy in predicting central neurological sequelae of 84%.

Predictive value of brain-stem auditory evoked potentials in children with post-traumatic coma produced by diffuse brain injury.

In the present study, brain-stem auditory evoked potentials (BAEPs) in 31 children in post-traumatic coma with diffuse brain injury were examined. The BAEPs were recorded in the first 72 h after hospital admission and the findings of 29 patients related to the level of neurological recovery at 6 months after head injury. On the basis of the results, children were divided into three groups: the first consisted of children with bilateral and normal BAEPs (n = 19); the second of those with asymmetrical BAEPs (n = 6); and the third of those in whom BAEPs has disappeared or in whom only responses of the seventh cranial nerve and cochlear nucleus were recorded (n = 4). All the patients in the first group presented a good clinical outcome, with excellent recovery in 80%. In the second group three children (42.8%) had a good recovery, two (28.6%) were moderately disabled and one (14.3%) died of extraneurological causes. All the patients in the third group died. Abnormal BAEPs showed a significant correlation with absence of pupillary and/or corneal reflex, but not with the Glasgow Coma Score and anisocoria. Good statistical correlation was observed between normal BAEPs and visualization of basal cisterns on computed tomographic scan. The incidence of increased intracranial pressure was higher in patients with abnormal BAEPs, but the differences were not significant (P = 0.06). Our study confirms the predictive value of BAEPs in children's post-traumatic coma due to diffuse brain injury.

Brainstem auditory-evoked potentials and neuropathologic correlates in 26 dogs with brain tumors.

Brainstem auditory-evoked potentials (BAEPs) were recorded from 26 dogs with intracranial neoplasia. The tumors were grouped according to their neuroanatomic location. Normal BAEPs were recorded from 12 dogs with cerebral (6/7), diencephalic (4/4), cerebellar (1/1), and multifocal tumors (1/5). Abnormal BAEPs were recorded from 14 dogs were cerebral (1/7), cerebellar/brainstem (4/4), brainstem (5/5), and multifocal tumors (4/5). Analysis of the multifocal neoplasms showed that alterations of BAEPs correlated with the degree of brainstem involvement. Overall, 13 of the 14 dogs with abnormal BAEPs had tumors involving the brainstem. The changes of the BAEP correlated with the extrinsic or intrinsic location of the tumor relative to the brainstem. The BAEP reflected the right, left, or median location of the tumor in 7 of the 14 abnormal recordings. In 1 dog, the BAEP was abnormal contralateral to the tumor side. A peripheral hearing disorder was excluded in most dogs based on the presence of peak I.