Electrophysiological (EEG, BAEP, VEP) study in patients with beta-thalassemia major

Twenty-four patients affected by beta-thalassemia major were studied by means of combined EEG, VEP and BAEP recordings. All the subjects were treated with regular blood transfusions and chelating therapy (DFO). An elevated incidence of EEG abnormalities (70.8%) consisting of diffused slow waves and/or diffused small sharp spikes was seen. VEP P100 latency was abnormally prolonged in eight patients (33.3%). Furthermore, a voltage increase of N75-P100 (29%) and P100-N145 (33.3%) VEP components was observed. Mean latency and voltage values were significantly increased when compared with those of a control group. No BAEP alterations were observed. No correlations were found between electrophysiological data, serum ferritin levels and transfusional treatment duration. The possible mechanisms involved in provoking such electrophysiological abnormalities are discussed.     

Brain stem auditory and visual evoked potentials in multiple sclerosis

The diagnostic value of the checkerboard pattern-reversal visual evoked potential (VEP) and the random, low rate stimulated brain stem auditory evoked potential (BAEP) was compared in 99 patients with established or suspected multiple sclerosis (MS). In normal subjects examined by both techniques no abnormal recordings were found. In 49 patients with definite MS an incidence of abnormality was found in 100% of VEP and in 84% of BAEP recordings. In 50 patients with probable or possible MS an abnormal VEP was found in 70% and an abnormal BAEP in 50%. When the two examinations were combined, the diagnostic yield increased to 100 and 80%, respectively. 22 patients had only spinal symptoms; in these the VEP gave 73%, the BAEP 55% and the combination 82% abnormalities. The combination of the two techniques was found useful for demonstrating demyelinating lesions in the central nervous system, the diagnostic value being greatest when these lesions were clinically silent.     

Neurophysiologic assessment of mucopolysaccharidosis III.

OBJECTIVE: To describe finding of various neurophysiologic tests in patients with mucopolysaccharidosis III (MPS III) early in the disease course. METHODS: Patients were evaluated with flash visual evoked potentials (VEP), brainstem auditory evoked potentials (BAEP), electroencephalography (EEG), and nerve conduction studies (NCS) before they underwent hematopoietic stem cell transplantation (HSCT). RESULTS: Thirteen children underwent at least one neurophysiologic test before HSCT. The mean age at testing was 2.7 years. Ten of 11 (91%) patients had a normal flash VEP, and all 9 who had BAEP had normal central conduction. EEG was normal in 7/13 (54%), with the others showing diffuse slowing. NCS was normal in 10/11 (91%) patients. CONCLUSIONS: Despite extensive central nervous system involvement in MPS III, flash VEP and BAEP are almost always normal. EEG is often abnormal early in the disease. SIGNIFICANCE: This is the first report of neurophysiologic tests in a large series of MPS III patients.     

Objective measurement of hepatic encephalopathy in pigs by means of spectral analysis and evoked responses

Objective measurement of hepatic encephallopathy by means of spectral analysis of the electroencephalogram (EEG), visual-evoked potentials (VEP) and brainstem auditory-evoked potentials (BAEP) was studied in pigs with ischemic hepatic necrosis. The mean dominant frequency (MDF) and the relative power off the delta frequency band (%δ power) showed significant changes with increasing encephalographic grades of encephalopathy: MDF dropped from 7.0 ± 0.5 (grade 0) to 2.7 ± 0.3 Hz (grade 3 encephalopathy) and %δ power increased from 52 ± 7 (grade 0) to 83 ± 6% (grade 3). The patterns of the VEP in piogs corresponded to those of the human VEP. However, significant differences in either latency time of the peaks or the peak amplitude with increasing stages of hepatic encephalophaty could not be found. The BAEF registered for pigs were reproducible but also were not as useful as spectral analysis for grading hepatic encephalopathy.     

Evoked potentials

ABSTRACT- A survey is given of my studies of evoked potentials in patients with multiple sclerosis (MS) and in control subjects. Potentials were recorded following random low-rate auditory stimulation (BAEP), checkerboard pattern-reversal stimulation (VEP), somatosensory stimulation (SEP); blink reflexes (BR) were recorded following electrical stimulation of the supraorbital nerve. Normal data had to be related to age and sex in evaluating BAEPs and VEPs.
In 160 MS patients, a total of 421 recordings were obtained. Changes by repeated BAEP and VEP tests might reflect changes in the clinical state, but they also did occur in clinically stable patients. In patients with definite MS, high incidences of abnormality were shown, supporting the clinical findings. The diagnostic value was greatest when clinically silent lesions were demonstrated in patients with suspected or possible MS. In these patients, either BAEP or VEP gave evidence of subclinical lesions in about 50%, and when combined, in 71% of the patients, thus making a transfer to a more certain diagnostic classification possible and invasive examinations unnecessary. When SEP and BR tests were added, subclinical lesions were found in 74% of the patients. The SEP recordings did show a high incidence of abnormality, but only few silent lesions; the BR test was the least sensitive. The VEP was abnormal in all patients with signs of optic neuritis and in all but one with a history of optic neuritis.
The present results are compared to those obtained in other laboratories and with other types of examinations in MS patients. It is concluded that although the tests are not specific for MS, they give valuable information in the majority of patients with a clinically uncertain diagnosis. This information will most often not be given by other types of examination. The combination of VEP and BAEP is recommended, but it should be supplemented by SEP recording in patients without spinal signs.     

Evaluation of electrophysiological neuromonitoring in the diagnosis of brain death: Part I. Brainstem auditory evoked potentials

Electrophysiological neuromonitoring of brainstem auditory evoked potentials (BAEP), short-latency somatosensory evoked potentials (SSEP) and compressed spectral array (CSA) EEG can provide precise and immediate information concerning functional integrity of the brain, brainstem and upper spinal cord of severely brain-damaged patients. We applied this neuromonitoring system in the cases of 154 severely brain-damaged patients in order to evaluate its reliability in the diagnosis of brain death. In particular, this study considers the relationships between BAEP and neurological findings, conventional EEG findings and factors affecting final BAEP findings. As a result, we evaluated the significance of BAEP in the diagnosis of brain death. A total of 109 brain-dead patients were divided into two groups: group A with 48 patients determined brain dead neurologically and by EEG prior to BAEP monitoring, and group B with 61 patients who had undergone automatic BAEP monitoring every 10 to 30 minutes before and/or after determination of clinical brain death. A third group, C, included 45 non brain-dead patients subjected to neuromonitoring, and served as a comparative group. Brain damage was caused by subarachnoid hemorrhage in 50 patients, intracerebral hemorrhage in 36, cerebral infarction in 8, head injury in 47, meningitis in 3, brain tumor in 3 and anoxia in 7. There were no significant differences in causes among the three groups (chi 2 = 20.3). The mean ages in the three groups were 50 (ages 10-91) in group A, 51 (14-86) in group B, and 50 (5-87) in group C. There were no significant differences in age distribution among the three group (chi = 25.0). The last BAEP findings of the 109 brain-dead patients indicated loss of all waves in 99 (91%), the presence of wave I in 9 (8%), and the presence of waves I and II in one patient (1%) (Table 1). Only three of the 45 group C non brain-dead patients indicated loss of all BAEP waves within one month after onset (Table 1). The one demonstrated loss of all BAEP waves 17 days after her accident, with recovery of waves I to V three months later. The temporal relationships in group B patients of the course of BAEP findings and the time of neurological brain death diagnosis are shown in Table 2 and Fig. 1. All but two of the 61 patients were followed up until final loss of BAEP waves (Fig. 1).(ABSTRACT TRUNCATED AT 400 WORDS)     

Evoked potentials and electroencephalography in adolescents with phenylketonuria

We studied the pattern-reversal VEP, the BAEP and the EEG with conventional and computerized analysis in 41 adolescents with hyperphenylalaninemia (24 HPA type 1, 12 HPA type 2, 4 HPA type 3, 1 DHPR deficiency) and 35 control persons. A prolongation of the P100 latency in the VEP, a greater interear difference of the I-V interwave latency in the BAEP and slowing of EEG background activity were found. Five per cent of the patients demonstrated spikes and 12.5% abnormal sharp transients in the EEG. The latency increase in the VEP corresponded to the compliance with the diet during the first decade of life. No influence of the actual Phe concentration at the time of the investigation was demonstrated. The BAEP- and EEG-findings were not related to the course of treatment. Thus the VEP changes in this cross sectional study refer to alterations of brain function that occurred during the early years of life. To investigate the value of evoked potentials and EEG in monitoring brain function after discontinuing the diet longitudinal data are needed.     

Recording of brainstem evoked potentials and their association with gentamicin in neonates

Brainstem auditory evoked potential (BAEP) recording was used to screen presymptomatically the hearing of 200 neonates treated with ampicillin (100 mg/kg daily) and gentamicin sulfate (5 mg/kg daily). The study included 130 male and 70 female neonates; post-conceptional age ranged from 34 to 57 weeks (mean 42.36 weeks). We divided neonates into 2 groups according to duration of antibiotic treatment; group 1 consisted of 179 patients who were treated with antibiotic agents for 7 days. Although 15 (8.4%) in this group initially manifested abnormal BAEP recordings, only 8 of these brain-damaged neonates (4.5%) (6 with peripheral and 2 with central dysfunction) later manifested abnormal recordings. Group 2 consisted of 21 neonates who were treated for 10 to 30 days; BAEP recordings were abnormal in 7 patients (33.3%) (4 with peripheral and 3 with central dysfunction). We conclude that BAEP is indicated only for neonates treated with gentamicin sulfate for>10 days. In this group, infants so treated usually have underlying disease or severe infection, including birth asphyxia, hypoxia, sepsis, and meningoencephalitis, all of which are clinically significant indicators of high risk for auditory pathway dysfunction.     

Visual and auditory evoked potentials in the early diagnosis and follow-up of neurosarcoidosis

Visual and brainstem auditory evoked potentials (VEPs, BAEPs) were recorded in 23 patients with neurosarcoidosis. Eight patients (35%) had abnormal BAEPs, and 10 (43%) had abnormal VEPs. Four of the 8 patients with abnormal BAEPs had facial paresis, one had impaired memory and only 3 had symptoms and signs compatible with brainstem lesion. Seven of the patients with abnormal VEPs had no visual symptoms. These findings suggest that BAEP and VEP can reveal subclinical nervous system involvement in sarcoidosis and can also help in the early diagnosis of neurosarcoidosis. Successive recordings of 5 patients showed that BAEP and VEP were useful in the follow-up of these patients.     

The diagnostic reliability of magnetically evoked motor potentials in multiple sclerosis.

In a prospective study, we evaluated the technique of magnetically evoked motor potentials (MEP) in the diagnosis of multiple sclerosis (MS). We consecutively included 68 patients with symptoms or signs compatible with a demyelinative CNS affection. We subjected all patients to CSF analysis, MRI studies of the brain and brainstem, visual evoked potentials (VEP), brainstem auditory evoked potentials (BAEP), and somatosensory evoked potentials (SSEP). We then used the results to categorize the patients according to the Poser criteria of multiple sclerosis. Blinded from the results of the above investigations, one of the authors made MEP recordings from three muscles in the upper limbs and two in the lower limbs in all 68 patients. Forty patients received an MS diagnosis, and in these, MRI was positive in 88%, MEP in 83%, VEP in 67%, SSEP in 63%, and BAEP in 42%. As to the diagnosis of MS, the reliability of a prolonged central motor conduction time (CMCT) was 0.83 (0.73 to 0.93), while the reliability of a normal CMCT was 0.75 (0.61 to 0.98). The information gained by MRI was best supplemented by VEP. Of the neurophysiologic tests, the MEP was in closest agreement with the MRI with a concordance of 85%.     

Brain-stem auditory evoked potentials in multiple sclerosis: the relation to VEP,SEP and CSF immunoglobulins

Summary One hundred patients with multiple sclerosis (MS) were analysed retrospectively with respect to investigations of brain-stem auditory evoked potentials (BAEP), pattern reversal visual evoked potentials (VEP), somatosensory evoked potentials (SEP), and cerebrospinal fluid immunoglobulins (CSF-IG). BAEP were abnormal in 42% of those with normal VEP and SEP examinations, and in 38% of patients with normal CSF-IG. The chance of obtaining at least one abnormal EP was lower in patients with normal CSF-IG than in patients with abnormal CSF. When a dispersion ratio was included in the criteria for BAEP abnormality, the sensitivity increased compared with conventional BAEP criteria. We recommend that BAEP should still be included in the EP test battery for patients with suspected MS.     

Deep brain stimulation of the subthalamic nucleus affects resting EEG and visual evoked potentials in Parkinson's disease.

OBJECTIVE: We studied changes of the EEG spectral power induced by deep brain stimulation (DBS) of the subthalamic nucleus (STN) in patients with Parkinson's disease (PD). Also analyzed were changes of visual evoked potentials (VEP) with DBS on and off. METHODS: Eleven patients with advanced PD treated with bilateral DBS STN were examined after an overnight withdrawal of L-DOPA and 2 h after switching off the neurostimulators. All underwent clinical examination followed by resting EEG and VEP recordings, a procedure repeated after DBS STN was switched on. RESULTS: With DBS switched on, the dominant EEG frequency increased from 9.44+/-1.3 to 9.71+/-1.3 Hz (P<0.01) while its relative spectral power dropped by 11% on average (P<0.05). Switching on the neurostimulators caused a decrease in the N70/P100 amplitude of the VEP (P<0.01), which inversely correlated with the intensity of DBS (black-and-white pattern: P<0.01; color pattern: P<0.05). CONCLUSIONS: Despite artifacts generated by neurostimulators, the VEP and resting EEG were suitable for the detection of effects related to DBS STN. The acceleration of dominant frequency in the alpha band may be evidence of DBS STN influence on speeding up of intracortical oscillations. The spectral power decrease, seen mainly in the fronto-central region, might reflect a desynchronization in the premotor and motor circuits, though no movement was executed. Similarly, desynchronization of the cortical activity recorded posteriorly may by responsible for the VEP amplitude decrease implying DBS STN-related influence even on the visual system. SIGNIFICANCE: Changes in idling EEG activity observed diffusely over scalp together with involvement of the VEP suggest that the effects of DBS STN reach far beyond the motor system influencing the basic mechanisms of rhythmic cortical oscillations.     

The value of brain stem auditory, visual and somatosensory evoked potentials and blink reflexes in the diagnosis of multiple sclerosis

Cervical and cortical somatosensory evoked potentials (SEP) following electrical stimulation of the median nerve and blink reflexes (BR) following electrical stimulation of the supraorbital nerve were recorded in 30 normal subjects aged 20–49 years. Subjects aged 40–49 had longer SEP latencies than subjects aged 20–39 years.
A total of 29 slightly affected patients with multiple sclerosis (MS) aged 26–49 years, including four patients without clinical signs (suspected MS) and 19 patients with signs indicating only one lesion (possible MS) were examined by low-rate random-stimulated brain stem auditory (BAEP), checkerboard pattern-reversal visual evoked potentials (VEP), SEP and BR. Abnormal recordings by at least one of the examinations were found in all but three patients, and by all four tests in five patients.
In patients with definite or probable MS, demonstration of clinically recognized or subclinical lesions was of minor diagnostic value, in contrast to the importance such findings had in patients with suspected or possible MS. Silent lesions were shown by at least one of the tests in the four suspected and in 13 of the possible MS patients, so these 17 patients could be transferred to a more certain diagnostic category. This reclassification was most often due to the BAEP recording.
In patients with spinal signs, the combination of BAEP and VEP recording was sufficiently efficient. In patients with optic neuritis a combination of BAEP and SEP was preferred. No abnormal recordings were found in 15 normal subjects examined by all four tests.     

Early brain stem auditory evoked potentials in brain death

Brain-stem auditory evoked potentials (BAEPs) are realized after the first flat EEG in 50 patients. BAEPs were absent in 70% of the patients. In 22% of the patients, one- or two-sided peak I persists. In 8% the peaks I, II and IV exist after the first flat EEG. BAEP evolution with the course of time is realized. A complete disappearance is established after 24 h. The useful advantage of BAEPs in the early diagnosis of brain death is discussed.     

帕金森病患者抑郁与脑功能相关研究

目的 研究帕金森病患者脑功能及其与抑郁发生的相关性。方法 70例患者检查脑电图(EEG)、脑电地形图(BEAM)和脑干听觉诱发电位(BAEP)。汉密尔顿抑郁量表(HAMD)测试患者抑郁状态,并设正常对照组。结果 伴抑郁PD患者29例,占41.4％以运动迟缓和肌强直为主;无抑郁41例,以震颤为主。伴抑郁EEG和BAEP异常10例(12/29,41.4％)和17例(17/29,58.6％),无抑郁PD患者为9例(8/41,19.5％)和14例(14/41,34.1％),2组比较,P<0.05;伴抑郁PD患者BEAM表现为双侧额叶、顶叶和中央区θ、δ相对功率显著增加(P<0.01);BAEP表现为主波潜伏期和波间期延长。HAMD分值越高,EEG、BEAM和BAEP异常率越高。结论 PD患者抑郁的发生与脑功能异常关系密切。     

Visual, early auditory and somatosensory evoked potentials in multiple sclerosis (917 cases)

Visual (VEP), brainstem auditory (BAEP) and somatosensory (SEP) evoked potentials were recorded over a 6 year period in 917 patients with or suspected of multiple sclerosis according to Mc Alpine's criteria. Evoked potentials provided information of diagnostic relevance in detecting clinically unsuspected lesions (spatial dissemination). They also gave valuable informations in patients with atypical or borderline clinical features. When abnormal, VEP indicated clinically silent lesions in 45.1 p. 100 of patients with definite MS, 66 p. 100 of those with probable MS and 78 p. 100 of the possible MS. Less than 15 p. 100 of SEP and/or BAEP abnormalities were found in 83 patients with a simple or recurring retrobulbar optic neuritis. Thirteen patients with acute transverse myelopathy and no prior history of neurological disease were studied. All had normal visual and brainstem auditory evoked potentials. Abnormal VEPs helped to the clinical assessment of 88 patients with progressive spastic paraparesis 46,6 p. 100 of whom had abnormal VEPs demonstrating disseminated lesions and 36,1 p. 100 had abnormal BAEPs. The frequency of the various types of VEP, BAEP and SEP abnormalities was studied as well as their course on repeated recordings. Results of multivariate analysis are given. It was found that the longer the time interval between the first MS relapse and the evoked potential recording, the higher the incidence of abnormalities. The incidence of evoked potentials abnormalities was lower in patients with normal CSF and higher in patients with inflammatory CSF. The abnormalities were more frequent when patients had clinical evidence of lesions of the sensory pathways explored by the tests.     

Neurophysiologic and intellectual evaluation of beta-thalassemia patients

In order to detect involvement of the central and peripheral nervous system in beta-thalassemic patients, 32 children and young adults (mean age 14.5 +/- 6.4 years) participated in a systematic neurophysiologic and intellectual prospective study. All patients were in a regular transfusion program, receiving subcutaneous desferrioxamine chelation and maintaining a mean serum ferritin level of 2,101.56 +/- 986.32 ng/ml. Study patients underwent neurophysiologic evaluation consisting of brainstem auditory, visual and somatosensory evoked potential examination (BAEP, VEP, SEP) as well as motor and sensory nerve conduction velocity studies (MCV, SCV). Additionally, the verbal, performance and total IQ were assessed in patients under 16 years of age using the Weschler Intelligence Scale for Children (WISC-III). The incidence of abnormal BAEP, VEP, SEP and NCVs was 0, 3.12, 3.12 and 18.75%, respectively, findings comparative to or better than previously reported. On the contrary, the prevalence of abnormal total IQ score was considerably high (36.4%), not correlating, however, to any of the parameters assessed (age, sex, ferritin level, BAEP, VEP, SEP, NCV). Factors associated with chronic illness, rather than the disease per se, could play a potential role in the development of cognitive dysfunction in beta-thalassemia patients.     

Electroencephalogram and brainstem auditory evoked potential in 539 patients with central coordination disorder

BACKGROUND： Electroencephalogram （EEG） and brainstem auditory evoked potential （BAEP） are objective non-invasive means of measuring brain electrophysiology. OBJECTIVE： To analyze the value of EEG and BAEP in early diagnosis, treatment and prognostic evaluation of central coordination disorder. DESIGN, TIME AND SETTING： This case analysis study was performed at the Rehabilitation Center of Hunan Children＇s Hospital from January 2002 to January 2006. PARTICIPANTS： A total of 593 patients with severe central coordination disorder, comprising 455 boys and 138 girls, aged 1-6 months were enrolled for this study. METHODS： EEG was monitored using electroencephalography. BAEP was recorded using a Keypoint electromyogram device. Intelligence was tested by professionals using the Gesell scale. MAIN OUTCOME MEASURES： （1） The rate of abnormal EEG and BAEP, （2） correlation of abnormalities of EEG and BAEP with associated injuries, （3） correlation of abnormalities of EEG and BAEP with high risk factors. RESULTS： The rate of abnormal EEG was 68.6% （407/593 patients）, and was increased in patients who also had mental retardation （P 〈 0.05）. The rate of abnormal BAEP was 21.4% （127/593 patients）. These 127 patients included 67 patients （52.8%） with peripheral auditory damage and 60 patients （47.2%） with central and mixed auditory damage. The rate of abnormal BAEP was significantly increased in patients who also had mental retardation （P 〈 0.01 ）. Logistic regression analysis showed that asphyxia （P 〈 0.05）, jaundice, preterm delivery, low birth weight and the umbilical cord around the neck were closely correlated with abnormal EEG in patients with central coordination disorder, lntracranial hemorrhage, jaundice （P 〈 0.05）, low birth weight and intrauterine infection （P 〈 0.05） were closely correlated with abnormal BAEP in patients with central coordination disorder. CONCLUSION： Central coordination disorder is often associated with abnormal EEG an     

Diagnostic value of electroencephalography and brainstem auditory evoked potentials in dizziness

Electroencephalogram (EEG) and brainstem auditory evoked potentials (BAEP) were recorded from 142 dizzy patients. The results were compared with those obtained by other neurological examinations of the same patients. Thirty-three percent (N = 44) of the patients had an abnormal EEG: 21% (28) showed focal abnormality, 12% (16) irritative features, and 10% (13) generalized disturbance. There were no differences in the distribution of abnormal EEGs in different diagnostic categories of dizziness, but irritative findings were not found in the cases of peripheral vestibular or psychogenic disturbances. EEG findings in 3 patients suggested temporal epilepsy, correlating with the clinical picture. BAEPs were abnormal in 18% (N = 21) of the recordings. There were 3 cases of MS and 5 ischaemic lesions in the vertebro-basilar region. Twelve of the 13 other patients with abnormal BAEP showed evidence of CNS pathology with other methods. EEG abnormalities were mostly non-specific; however, the irritative findings suggested cerebral pathology, such as epilepsy. An abnormal BAEP offers reliable evidence for brainstem lesion and is thus a useful examination in dizziness.