Brainstem Auditory Evoked Potentials Parameters Research Articles

Vestibular evoked myogenic and auditory brainstem evoked potentials in a female migraine population.

<p>The purpose&nbsp;of the present study was to evaluate ocular vestibular evoked myogenic potential (oVEMP), cervical vestibular evoked myogenic potential (cVEMP), and brainstem auditory evoked potential (BAEP) response characteristics and to understand the pathophy&shy;siology of vestibular dysfunction in female migraineurs with vertigo symptoms. We also aimed to assess the electrophysiological di&shy;&shy;agnostic significance of the VEMP respon&shy;ses in vestibular migraine (VM).&nbsp;</p>. <p>23 patients with migraine without aura (MoA), 23 patients with VM, and 20 sex-and age-matched healthy controls, a total of 66 female participants were enrolled in this study. The outcome parameters were asymmetry ratios (ARs), amplitudes of oVEMP, cVEMP, N1P1, P13N23, and the respective latencies (mean &plusmn; SD). From the BAEP graphs, absolute and interpeak interval latencies of waves were analyzed.&nbsp;</p>. <p>30.4% of the MoA group and 21.7% of the VM group had uni- or bilaterally absent cVEMP responses which were statistically significant only in the MoA group (p=0.035) in comparison to control group. Both groups displayed statistically insignificant absent or asymmetrical responses for oVEMP (13.1%). Cervical VEMP P13 and N23 latency, peak-to-peak amplitude, interaural latencies, and amplitude ARs did not show any significant difference between MoA and VM patients and healthy controls. No significant difference was detected among the three groups in the oVEMP and BAEP parameters.</p>. <p>Although absent cVEMP responses were more common in MoA and VM patients than in healthy individuals, the VEMP and BAEP test results should not be used in the differential diagnosis of VM and MoA.&nbsp;</p>.

Normative data for brainstem auditory evoked potential responses in North Indian menopausal females

Background: Ovarian hormones are known to influence central neuronal functioning. Many studies have established the brainstem auditory evoked potential (BAEP) pattern vis-à -vis the cyclical fluctuations of these hormones in young females; however, there is a paucity of research involving BAEP patterns among menopausal females. Aim: This study was conducted to provide normative values for various BAEP parameters in menopausal females from North India. Materials and Methods: A cross-sectional study was done on 100 females aged 46–70 years. BAEP recording was done using a standardized protocol. The data were analyzed using SPSS software. It consisted of mean wave latencies I, II, III, IV, and V and interpeak latencies (IPL) I-V, I-III, and III-V. Student's unpaired t-test was used for statistical analysis. Results: The average value of means of wave latencies and IPL from both the ears was obtained. The latencies of waves I, II, III, IV, and V were 1.82 ± 0.27 ms, 2.81 ± 0.27 ms, 4.09 ± 0.35 ms, 4.87 ± 0.33 ms, and 6.19 ± 0.31 ms, respectively. The mean values of IPL I-V, I-III, and III-V were 4.37 ± 0.38 ms, 2.26 ± 0.33 ms, and 2.1 ± 0.32 ms, respectively. Conclusion: The study findings compared favorably with already existing data from similar studies conducted elsewhere. The data from the present study would prove useful to the clinicians to detect subtle neurodegenerative changes at an early stage within the central auditory pathways, even in the absence of any perceptible hearing loss, in this subset of population.

Brainstem auditory evoked potentials in patients with primary Sj\xf6gren\u2019s syndrome without central nervous system involvement

ObjectivesPrimary Sjögren’s syndrome (pSS) is an autoimmune, multisystem exocrinopathy characterized by dysfunction of the exocrine glands. Central nervous system (CNS) involvement is estimated to be present in 10–60% patients with pSS. The present study aimed to evaluate brainstem auditory evoked potentials (BAEP) in pSS patients without central nervous system involvement, and without otolaryngological abnormalities.MethodThirty-six pSS patients (35 women, 1 man, mean age 48 years old) and 40 healthy volunteers were investigated. BAEP, brain imaging, laboratory parameters, and clinical neurological and otolaryngological examinations were performed.ResultsAbnormal BAEP were recorded in 16.7% patients. The mean wave BAEP I and V latency and mean wave III-V and I-V interpeak latencies were significantly longer in pSS patients than the controls. There were no statistically significant correlations between BAEP parameters and laboratory tests. None of the patients was found having the abnormalities on brain imaging.ConclusionsThis study confirms that in pSS patients without clinical central nervous system impairment, auditory pathway disturbances could be found. Disorders of brain bioelectrical activity may be a consequence of ongoing autoimmune process.Key Points• BAEP abnormalities confirmed the clinically observed involvement of the central nervous system in patients with pSS.• Brain bioelectrical activity dysfunctions in pSS patients may be a consequence of ongoing inflammatory and/or immunological processes.

Differences in Electrophysiologic Values between Preoperative and Intraoperative Neurophysiologic Monitoring.

To compare preoperative and intraoperative electrophysiologic values in patients who underwent brain and spine surgeries. A retrospective medical record review was conducted on patients who underwent brain and spine surgery between January 2014 and July 2018. Patients underwent preoperative electrophysiologic monitoring within a week before the operation and intraoperative monitoring during the surgery. Monitoring parameters included the onset latency (msec) and amplitude (mV) of motor evoked potential (MEP), somatosensory evoked potential (SEP), electroneuronography, and brainstem auditory evoked potential (BAEP). The latency of the MEP and SEP were significantly prolonged while the amplitude was decreased during operation. Specifically, patients with abnormal findings in their preoperative assessments showed more prominent differences compared to those with normal findings. However, there was no significant difference between preoperative and intraoperative results based on which side of the hemisphere was affected or unaffected. Unlike the MEP and SEP parameters, there were no significant changes in the facial electroneuronography and BAEP parameters. There were differences in the preoperative and intraoperative monitoring parameters. Further studies are necessary to understand the underlying mechanisms behind these changes during surgery.

P35-F Brainstem auditory evoked potentials in patients with primary Sjögren’s syndrome

Background Primary Sjogren’s syndrome (pSS) is a chronic autoimmune exocrinopathy characterized by dysfunction of exocrine glands. Central nervous system (CNS) involvement is estimated to be present in 3–60% patients with pSS. The aim of our study was to evaluate parameters of brainstem auditory evoked potentials (BAEP) in pSS patients without clinical neurological deficit, and without otolaryngological abnormalities. Material and methods 36 patients with pSS (35 women, 1 man, mean age 49.3 years old) and 40 healthy controls, sex and age-matched were studied. They did not suffer from disease that could have affected the brain electrical activity. Clinical neurological and otolaryngological examinations, laboratory parameters (C3 and C4 component, ANA antibodies, RF levels), brain imaging (CT or MRI) and BAEP were performed. Statistical analysis was performed using the Statistica 10.0 PL software. Results In none of the patients were the abnormalities on brain imaging found. Abnormal BAEP were recorded in 6 patients (16.6%). pSS patients had a longer mean wave I and V latency and mean wave III-V and I-V interpeak latencies than the controls. There were no correlations between BAEP parameters and laboratory tests. Conclusions 1. In pSS patients without clinical central nervous system impairment the auditory pathway disturbances could be found. 2. Disorders of the brain bioelectrical activity in the course of pSS may be associated with an ongoing autoimmune process. item The analysis of BAEP may be useful methods of assessment of the CNS in patients without clinical neurological symptom.

Evoked brain potentials in patients with chronic vertebrobasilar ischaemia depending on the features of cerebral and regional perfusion

Objective. To evaluate the effectiveness of brain evoked potentials for the objectivization of early cognitive disorders (CD) induced by cerebral and regional hypoperfusion. Materials and methods. The influence of hypoperfusion in vertebrobasilar territory (VBT) on characteristics of cognitive functions in 52 patients with chronic brain ischemia was studied. The following methods were used: clinico-neurological, MRI, SPECT, duplex ultrasound scanning (DUS), EEG, and brain evoked potentials (EP). Results. The patients were split into two groups by DUS scan findings: 1 – those having structural lesions in vertebral arteries (VA), and haemodynamically significant disorders in VBT and 2 – those having none. The examination of patients of the 1 st group showed the following findings: high frequency of blood flow velocity decrease in VA; the tendency of decreasing in volumetric cerebral blood flow in brain segments and hemispheres according to SPECT data; prevalence of ataxia, coordination and long tract signs; high frequency of early CD in the domains of attention and memory; EP index changes. The patients with blood flow decompensation in VBT (according to DUS findings) showed changes in brainstem auditory EP parameters (BAEP): increase of III, IV, V latency peaks and III-V interpeak interval. According to the cognitive EP (CEP) study, the patients of the 1 st group consistently demonstrated higher frequency of N2 peak amplitude decrease, and P300 peak latency increase. Conclusions. Based on DUS scan findings, it is clinically appropriate to distinguish a group of patients with structural and haemodynamically significant disorders in VA. The deviations from the normal indices of CEP and BAEP correlate with CD occurring as a result of cerebral and regional hypoperfusion in VBT.

P286 Visual and brainstem auditory evoked potentials abnormalities in the patients with systemic lupus erythematosus

Objectives Lupus erythematosus (SLE) is a systemic disease with possible nervous system involvement, regarded as unfavorable prognostic factor. Evoked potentials (EP) are electrophysiological markers of disturbed central nervous system (CNS) function, even in subclinical stage of CNS disorders. The purpose of the study was to evaluate parameters of EP in the patients with SLE with or without neuropsychiatric manifestation (NPSLE). Methods The study comprised 53 patients with SLE (49 women, 4 men, aged 21–62, mean 38.3) and 40 healthy, age- and gender- matched controls. 33 patients were classified as having NPSLE. Visual evoked potentials (VEP) and brainstem auditory evoked potentials (BAEP) were performed in all the subjects. Latencies and amplitudes of VEP and BAEP components were compared between SLE patients and controls and between NPSLE and non-NPSLE patients. Results Mean latency of P100 component of VEP for the right eye was significantly longer (104.3 ms vs 102.06 ms; p = 0.05) and mean amplitude of the I component of BAEP for the right ear was significantly lowered (0.25 μ V vs 0.30 μ V; p = 0.04) in the SLE patients in comparison with the controls. No differences were found between NPSLE and non-NPSLE patients. Discussion Asymmetric abnormalities of EP correspond with multifocal brain damage in the course of SLE, although they are not specific for the background of the disease. Conclusions and significance Parameters of VEP and BAEP show asymmetric abnormalities in SLE patients, regardless of the clinical symptoms of CNS involvement. EP may be considered as electrophysiological markers of early CNS dysfunction in the course of SLE.

Brainstem Auditory Evoked Potentials' Diagnostic Accuracy for Hearing Loss: Systematic Review and Meta-Analysis.

Background Microvascular decompression (MVD) utilizes brainstem auditory evoked potential (BAEP) intraoperative monitoring to reduce the risk of iatrogenic hearing loss. Studies report varying efficacy and hearing loss rates during MVD with intraoperative monitoring. Objectives This study aims to perform a comprehensive review and study of diagnostic accuracy of BAEPs during MVD to predict hearing loss in studies published from January 1984 to December 2013. Methods The PubMed/MEDLINE and World Science databases were searched. Studies performed MVD for trigeminal neuralgia, hemifacial spasm, glossopharyngeal neuralgia or geniculate neuralgia and monitored intraoperative BAEPs to prevent hearing loss. Retrospectively, BAEP parameters were compared with postoperative hearing. The diagnostic accuracy of significant change in BAEPs, which includes loss of response, was tested using summary receiver operative curve and diagnostic odds ratio (DOR). Results A total of 13 studies were included in the analysis with a total of 2,540 cases. Loss of response pooled sensitivity, specificity, and DOR with 95% confidence interval being 74% (60-84%), 98% (88-100%), and 69.3 (18.2-263%), respectively. The similar significant change results were 88% (77-94%), 63% (40-81%), and 9.1 (3.9-21.6%). Conclusion Patients with hearing loss after MVD are more likely to have shown loss of BAEP responses intraoperatively. Loss of responses has high specificity in evaluating hearing loss. Patients undergoing MVD should have BAEP monitoring to prevent hearing loss.

Gender, nocturnal hypoxia, and arousal influence brainstem auditory evoked potentials in patients with obstructive sleep apnea.

Brainstem auditory evoked potential (BAEP) outcomes in obstructive sleep apnea syndrome (OSAS) patients are inconsistent in some studies because the affecting factors are not well controlled. This study aimed to evaluate BAEP of male and female patients with moderate and severe OSAS and further assess the possible factors influencing BAEP abnormalities. Polysomnography were applied to 118 subjects, composed of 84 OSAS patients and 34 control subjects (22 male, 12 female), during the night. OSAS groups included 40 moderate (32 male, 8 female) and 44 sever (36 male, 8 female) OSAS patients. Binaural BAEPs were performed for every subject before polysomnography. The comparison of BAEP among control, moderate, and severe OSAS groups was performed according to different gender. Independent sample t test was used to examine the difference between male and female groups. Pearson's correlation was applied between BAEP parameters and age, body mass index, and sleep-related data in OSAS group. Prolonged latencies of waves I, III, and V were observed in OSAS patients. They were significantly correlated with apnea hypopnea index, arousal index, and hypoxia-related parameters. Compared to female patients, male patients had longer latencies of waves III and V. For severe male OSAS patients, BAEP of right ear showed additional prolongations of IPLs of I-III and I-V than that of left ear, and the IPL of I-III was correlated with the severity of hypoxia. Moderate and severe OSAS patients showed abnormal BAEP which could be influenced by gender, nocturnal hypoxia, and arousal.

Evaluation of brainstem auditory evoked potentials and their relationshipwith levels of thyroid autoantibodies in patients with vitiligo.

Vitiligo is a common depigmenting disorder. The damage can also occur in similar ways to melanocytes within other organs. We evaluated the brainstem and auditory pathway functions by evaluating brainstem auditory evoked potentials (BAEPs) and whether there is any relationship between auditory functions and autoimmunity. Forty patients with vitiligo and 20 healthy volunteers were enrolled. Thyroid functions and autoantibodies were examined and BAEP tests were assessed by a neurologist. Antithyroid peroxidase (anti-TPO) and antithyroglobulin (anti-TGA) antibody positivity was higher in the patient group (P < 0.05). A negative correlation was detected between anti-TPO and lead III, IV, and V latency and I-III interpeak latency (IPL) of the right ear together with lead IV latency and I-V IPL of the left ear in the patient group. When each BAEP parameter was compared between the two groups, more abnormalities were detected in the V latency and III-V IPL of the left ear together with IV and V latency of the right ear. In this study the presence of a correlation between increased anti-TGA and anti-TPO levels and BAEP parameters may be related to an autoimmune-mediated mechanism. However, further studies are needed to be performed in a large patient series.

HEARING IMPAIRMENT IN CHILDREN WITH PERINATAL INJURIES OF CENTRAL NERVOUS SYSTEM

The results of two-stage audiologic examination (otoacoustic emissions method and assessment of auditory evoked potentials) of 74 term and premature newborns are shown in this article. All patients received treatment for perinatal injuries of central nervous system (cerebral ischemia of various stages of severity). The assessment of brainstem auditory evoked potentials was established to be the most informative diagnostic method both in term and premature infants, moreover the majority of newborns with perinatal brain injuries had increased latencies of brainstem auditory evoked potentials parameters and signs of acoustic analyzer dysfunction, which character depended on the severity of cerebral ischemia.

Acute and chronic effects of carbamazepine, phenytoin, valproate and vinpocetine on BAEP parameters and threshold in the guinea pig

ObjectiveTo characterize the acute and chronic effects of the antiepileptic drugs (AEDs): carbamazepine (CBZ), phenytoin (PHT), valproic acid (VPA) and vinpocetine (VPC), at doses 20, 6, 30 and 2mg/kg, respectively, on the latencies and amplitudes of the waves of brainstem auditory evoked potentials (BAEPs) elicited by a supra-threshold stimulus alongside BAEP threshold. MethodsBAEPs elicited by a stimulus of high (100dB nHL) intensity and BAEP thresholds were obtained at 4 and 8kHz: before, after the start of treatment, and following 28 days of a daily injection of the AEDs. ResultsAfter the start of treatment BAEPs were unchanged. After the long term treatment, CBZ and PHT increased P3 and P4 wave peak latencies and reduced P4 amplitude. Chronic VPA did not modify BAEP waves, and chronic VPC reduced P3 and P4 latencies. P1 and P2 were unchanged. BAEP thresholds at 4 and 8kHz were increased by CBZ, PHT and VPA, and decreased by VPC. ConclusionsThe chronic administration of several AEDs modifies BAEP waves of retro-cochlear origin. SignificanceAlterations in the generators of the later waves of BAEPs underlie, in most cases, the changes in hearing sensitivity produced by the long term treatment with AEDs at therapeutic relevant doses.

Block-dependent sedation during epidural anaesthesia is associated with delayed brainstem conduction

Neuraxial anaesthesia produces a sedative and anaesthetic-sparing effect. Recent evidence suggests that spinal cord anaesthesia modifies reticulo-thalamo-cortical arousal by decreasing afferent sensory transmission. We hypothesized that epidural anaesthesia produces sensory deafferentation-dependent sedation that is associated with impairment of brainstem transmission. We used brainstem auditory evoked potentials (BAEP) to evaluate reticular function in 11 volunteers. Epidural anaesthesia was induced with 2-chloroprocaine 2%. Haemodynamic and respiratory responses, sensory block level, sedation depth and BAEP were assessed throughout induction and resolution of epidural anaesthesia. Sedation was evaluated using verbal rating score (VRS), observer's assessment alertness/sedation (OAA/S) score, and bispectral index score (BIS). Prediction probability (PK) was used to associate sensory block with sedation, as well as BIS with other sedation measures. Spearman's rank order correlation was used to associate block level and sedation with the absolute and interpeak BAEP latencies. Sensory block level significantly predicted VRS (PK=0.747), OAA/S score (PK=0.748) and BIS. BIS predicted VRS and OAA/S score (PK=0.728). The latency of wave III of BAEP significantly correlated with sedation level (rho=0.335, P<0.01) and sensory block (rho=0.394, P<0.01). The other BAEP parameters did not change during epidural anaesthesia. Haemodynamic and respiratory responses remained stable throughout the study. Sedation during epidural anaesthesia depends on sensory block level and is associated with detectable block-dependent alterations in the brainstem auditory evoked responses. Sensory deafferentation may reduce CNS alertness through mechanisms related to brainstem neural activity.

The Validity of Intraoperative Brainstem Auditory Evoked Potentials (BAEPs) for the Postoperative Hearing Impairments in Microvascular Decompression (MVD)

Background: Intraoperative brainstem auditory evoked potentials reduced the sensorineural hearing loss (SNHL) after microvascular decompression (MVD). This study was performed to evaluate the validity of BAEP parameters of latency or amplitude to SNHL. Methods: 557 patients out of 930 hemifacial spasm patients performed MVD, who were free from hearing impairment preoperatively, were enrolled in this study. Maximal changes of BAEPs wave V latency and amplitude during MVD were retrospectively sought according to postoperative SNHL. Sensitivity, specificity and positive predictability of wave V latency and amplitude were also sought according to the postoperative SNHL with a critical value of 1.0 msec prolongation and 40% decrease, respectively. Results: Wave V latency of BAEPs prolonged less in patients with normal hearing outcome (0.44 0.63 msec) than in the patients with temporary or permanent SNHL (1.23 0.56 msec, 1.33 0.33 msec). Wave V amplitude also decreased less in the patients with normal hearing outcome (5.4 15.8%) than in the patients with transient or permanent SNHL (42.8 31.7%, 60.0 34.7%). While sensitivity, specificity and predictability of prolongation of wave V latency at a value of 1.0 msec for SNHL, were 52.5%, 76.4% and 14.7%, respectively, those of decrease in the amplitude of wave V for SNHL at a value of 40% were 35.0%, 93.6% and 29.8%, respectively. Conclusions: Decrease of the amplitude of wave V seems to have higher specificity, predictability and lower sensitivity for SNHL than the prolongation of wave V latency.

Effect of Thiopental Sodium on Hearing Outcomes Following Microvascular Decompression Surgery

Background: The use of intraoperative brainstem auditory evoked potential (BAEP) has reduced the incidence of sensorineural hearing loss (SNHL) after microvascular decompression (MVD). This complication occurs due to direct compressive and/or stretching injury of the cochlear nerve or to indirect compression of the perineural vasculature during cerebellar retraction. The aim of this study was to evaluate the effect of thiopental sodium on SNHL after MVD for hemifacial spasm. Methods: 94 hemifacial spasm patients with normal hearing function preoperatively and who underwent MVD under intraoperative BAEP monitoring were enrolled in this study. Patients were randomly divided into two groups. 52 patients were administered placebo (control group) and 42 patients were administered thiopental sodium 5 mg/kg intravenously 5 minutes before cerebellar retraction (thiopental group). The effects of thiopental on intraoperative BAEP changes and postoperative hearing functional outcomes were sought. Incidence and degree of postoperative SNHL were evaluated by pure tone audiometry threshold analysis. Results: Maximal changes in intraoperative BAEP parameters did not differ between the two groups, and neither did the incidence nor degree of SNHL. In the control group, 4 transient and 4 permanent postoperative SNHL, including 2 deaf patients, occurred with an overall incidence of 15.4%. In the thiopental group, 2 transient and 1 permanent postoperative SNHL occurred, with an overall incidence of 7.1%. Conclusions: Thiopental sodium administered prior to cerebellar retraction might reduce the incidence of postoperative hearing loss.

The brainstem auditory evoked potential abnormalities in severe chronic obstructive pulmonary disease.

The aim of the study was to investigate the abnormalities of brainstem auditory evoked potentials (BAEP) in patients with severe chronic obstructive pulmonary disease (COPD). Twenty-one patients with severe COPD (16 men, five women; mean age: 64 +/- 6.5 years), in whom other causes of BAEP abnormalities had been excluded, were studied. Age-matched, non-smoking, healthy subjects acted as a control group. We performed pulmonary function tests, arterial blood gas analysis and bilateral BAEP measurements in COPD patients and control groups. Brainstem auditory evoked potentials were abnormal in 16 (76.1%) of the 21 COPD patients. Most prominent BAEP abnormalities were prolonged wave I peak latencies (42.8%), V wave peak latencies (38.1%), and III-V interpeak latencies (IPL) (38.1%). In five patients, a prolonged central transmission time (I-V IPL) was observed. No significant correlation was evident between the BAEP parameters and pH, PaO2, PaCO2, FEV1%, FEV1/FVC, haematocrit, duration of disease or cigarette consumption. The functions of the eighth cranial nerve and brainstem were highly impaired in severe COPD. These pathological BAEP alterations in severe COPD might be due to the chronic hypoxic-hypercapnic status occurring in the brainstem.

Brainstem auditory evoked potentials characteristics in mice: The effect of genotype

Brainstem auditory evoked potentials (BAEPs) elicited by sound clicks were recorded as a function of stimulus intensity in pentobarbital anesthetized C57BL/6J and BALB/c male mice, 2.5 months old. At high stimulus intensities the BAEPs of both strains consisted of 4 positive and 4 negative waves (labelled P1-P4 and N1-N4, correspondingly). However, great interstrain differences were observed. BALB/c mice were characterized by higher thresholds, less amplitudes, beginning with P1 peak, longer latencies and steeper in slope latency-intensity profiles. The data suppose that by this age C57BL/6J mice have better auditory acuity, than BALB/c, and in BALB/c mice the pronounced abnormalities appear to arise in cochlear-auditory nerve system. Analysis of BAEPs using interpeak latencies (IPLs) and amplitude ratios intensities (ARs) profiles technique demonstrated no general trend that could fit for all IPLs as well as for all Ars changes by varying stimulus intensity. The obtained interstrain and interpeak differences in BAEPs parameters suggest that auditory information processing may vary greatly as a function of brainstem level.

A cross-sectional study on the brainstem auditory evoked potential among workers exposed to carbon disulfide

In order to clarify the chronic effect of carbon disulfide (CS2) on the central nervous system (CNS), the brainstem auditory evoked potential (BAEP) was measured in spinning workers exposed to CS2 in a viscose rayon manufacturing factory and unexposed workers in Japan. Workers exposed to CS2 were divided into three groups according to length of exposure: current spinning workers with an exposure duration of more than 240 months (L group, n = 34), current spinning workers with an exposure duration of 24-84 months (S group, n = 25), and former spinning workers with an exposure duration of more than 120 months (R group, n = 16). Unexposed controls were selected from workers in a nylon filament factory using the same criteria (N group; n = 40). BAEP records were analyzed based on the latencies of three main components (I, III, V) and interpeak latencies (I-III IPL, III-V IPL, I-V IPL). Latencies of component V, III-V IPL, and I-V IPL in the L group were significantly greater (P < 0.01, P < 0.05, P < 0.05, respectively). The significantly, higher III-V IPL in the L group suggested that in humans, chronic exposure to CS2 involves the auditory ascending tract in the brainstem. Recovery from this neurotoxic effect is apparently possible, as the BAEP parameters in the R group were not significantly higher than those of the N group despite the long previous CS2 exposure of the R group.

Effects of age on event-related potentials in chronic alcoholics: a multimodal study.

To test different versions of the premature aging hypothesis in alcoholics, brainstem auditory evoked potentials (BAEPs), long-latency auditory evoked potentials (LAEPs), P3 and visual evoked potentials (VEPs) were recorded in 32 alcoholic subjects. The phenomena in patients' event-related potentials (ERPs) differ from those observed in normal aging subjects and become more pronounced with age. ANOVA showed a significant effect by group (alcoholic patients/controls) on certain parameters of BAEPs (III, III-V, I-V), VEPs (P100 latency) and LAEPs (N1-P2 amplitude and N2 latency) unaffected by age, while age had a significant effect on some parameters of LAEPs (N2-P3 amplitude, P3 latency) unaffected, or less affected by chronic alcohol consumption. At a clinical level, abnormalities in BAEPs and VEPs seem good early trouble indices in alcoholic patients, while alterations in latencies and amplitudes of LAEPs appear in older patients. These data seem to be in favor of a critical age or critical abuse in the action of alcohol, in place of the classical hypothesis of premature aging.

Brainstem auditory evoked potential (BAEP) abnormalities in brucellosis

Twelve patients with neurobrucellosis and 17 patients with systemic brucellosis without neurological involvement underwent a brainstem auditory evoked potentials (BAEP) study. All neurobrucellosis patients (100%) showed abnormalities in their BAEP recordings, suggestive of brainstem lesions at various levels. On the other hand, only 5 (29%) of the 17 patients with systemic brucellosis had mild unilateral BAEP abnormalities, while the remaining 12 had normal responses. Comparison of pooled data between the systemic brucellosis and neurobrucellosis groups showed highly significant differences in all BAEP parameters. The recording of BAEP is thus considered a sensitive supplementary method to reveal CNS lesions in patients with neurobrucellosis.