Abnormalities Of Evoked Potentials Research Articles

Multimodal evoked potentials are useful for the diagnosis of pediatric acute disseminated encephalomyelitis.

The application of evoked potentials (EPs) to the diagnosis of acute disseminated encephalomyelitis (ADEM ) has not been investigated in detail. The aim of this study, therefore, was to analyze the value of multimodal EPs in the early diagnosis of pediatric ADEM. This was a retrospective study in which we enrolled pediatric ADEM patients and controls (Cs) from neurology units between 2017 and 2021. We measured indices in patients using brainstem auditory evoked potentials (BAEPs), visual evoked potentials (VEPs) and somatosensory evoked potentials (SEPs), and then we analyzed their early diagnostic value in ADEM patients. The mean age of the ADEM group was 6.15 ± 3.28 years (range,1-12 years) and the male/female ratio was 2.1:1 The mean age of the Cs was 5.97 ± 3.40 years (range,1-12 years) and the male/female ratio was 1.3:1. As we used magnetic resonance imaging (MRI) as the diagnostic criterion, the sensitivity, specificity, and accuracy (κ was 0.88) of multimodal EPs were highly consistent with those of MRI; and the validity could be ranked in the following order with respect to the diagnosis of ADEM: multimodal Eps > single SEP > single VEP > single BAEP. Of 34 patients with ADEM, abnormalities in multimodal EPs were 94.12%, while abnormalities in single VEPs, BAEPs and SEPs were 70.59%,64.71%and 85.3%, respectively. We noted significant differences between single VEP/BAEPs and multimodal EPs (χ2 = 6.476/8.995,P = 0.011/0.003). The combined application of multimodal EPs was superior to BAEPs, VEPs, or SEPs alone in detecting the existence of central nerve demyelination, and we hypothesize that these modalities will be applicable in the early diagnosis of ADEM.

Analysis of factors correlated with spinal clinically isolated syndrome conversion to multiple sclerosis.

The present study aims to explore the factors influencing spinal clinically isolated syndrome (CIS) conversion to multiple sclerosis (MS). Sixty-one patients diagnosed with spinal CIS from January 2010 to November 2020 were divided into a non-progressing (CIS) group with 27 patients, and a conversion to MS (MS) group with 34 patients, based on whether they had converted to MS. The clinical presentation at onset, the Expanded Disability Status Scale (EDSS) before and after steroid therapy, the results of magnetic resonance imaging (MRI), the oligoclonal bands in cerebrospinal fluid (CSF-OCB), and the evoked potentials (EPs) were retrospectively analysed. Differences in gender and age were not statistically significant between the MS and CIS groups. The median time to relapse was 12 months for the MS group, with an upper quartile of 23.7 months, and 91.2% of patients relapsed within three years. In univariate analysis, patients with CIS beginning with sensory symptoms had a lower level of progression to MS (OR = 0.311). Patients with Kurtzke Functional Systems Scores (FSSs) of pyramidal functions ≥ 2 (OR = 3.582) and positive CSF-OCB (OR = 5.208) quickly progressed to MS. There was no significant difference between the two groups in terms of spinal cord lesions < 3 vertebral segments, gadolinium enhancing lesions, or abnormal EPs. The difference in the EDSS scores before and after steroid therapy was higher in the MS group than in the CIS group (p = 0.001). Differences of ≥ 1.5 in the EDSS scores before and after steroid therapy were risk factors for CIS conversion to MS (OR = 9.333). Patients with spinal CIS with pure sensory abnormalities at onset were less likely to convert to MS (OR = 0.311), and the risk factors were, in order of risk, the difference in EDSS score before and after steroid therapy (≥ 1.5; OR = 9.333), positive CSF-OCB (OR = 5.208), and those with an FSS of the pyramidal functions score ≥ 2; OR = 3.582). The present study serves as a simple 'first step'. Any potential predictors identified should be validated via future prospective studies.

Clinical utility of complex assessment with evoked potentials in acute lymphoblastic leukemia survivors: comparison of various treatment protocols

BackgroundOne of the greatest success of pediatric hematology is a prominent improvement of survival in acute lymphoblastic leukemia (ALL). Therefore, special attention needs to be paid to long-term side effects of the treatment such as neurotoxicity. One of the few diagnostic methods that allow an objective assessment of sensory systems are evoked potentials (EP).MethodsThe analyzed group consisted of 167 ALL long-term survivors, aged 4.9–28.4 years, without auditory, visual and sensory deviations. Patients were treated with New York (NY, n = 35), previous modified Berlin-Frankfurt-Münster (pBFM, n = 47) and BFM95 (n = 85) protocols. In order to assess the impact of radiotherapy on recorded EP, a joint analysis of NY and pBFM groups was performed. The control group consisted of 35 patients, aged 6–17 years. The analyzed patients underwent a complex assessment with visual EP (VEP), somatosensory EP (SEP) and brainstem auditory EP (BAEP) in accordance with current standards.ResultsALL treatment contributed to the shortening of wave I latency (1.59 vs 1.90, P = 0.003) and prolongation of I-III (2.23 vs 2.04, P = 0.004) and I-V (4.57 vs 4.24, P = 0.002) interwave latencies of BAEP. A significant effect was also noticed in P100 (106.32 vs 101.57, P < 0.001) and N135 (151.42 vs 138.22, P < 0.001) latencies of VEP and N18 amplitude (3.24 vs 4.70, P = 0.007) and P25 latency (21.32 vs 23.39, P < 0.001) of SEP. The distribution of abnormalities between protocols was similar in BAEP (NY - 68.6%, pBFM - 61.7%, BFM95–69.4%, P = 0.650), VEP (NY - 68.6%, pBFM - 42.5%, BFM95–58.3%, P = 0.053) and significantly different for SEP (NY - 62.9%, pBFM - 36.2%, BFM95–53.0%, P = 0.045). The harmful effect of radiotherapy was most clearly marked in numerous disturbances of SEP parameters.ConclusionsThe presented analysis indicates a high frequency of subclinical abnormalities in EP regardless of the analyzed protocol. To our knowledge current study is the largest and one of the most complex research examining the role of EP in ALL patients. The obtained results indicate the possibility of using a single, objective and non-invasive measurement of EP in ALL survivors in order to stratify the risk of developing sensory abnormalities in adulthood.

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.

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.

Evoked potentials are useful for diagnosis of neuromyelitis optica spectrum disorder

Neuromyelitis optica spectrum disorder (NMOSD) has been differentiated from relapsing-remitting multiple sclerosis (RRMS) by clinical, laboratory, and pathological findings, including the presence of the anti-aquaporin 4 antibody. Measurement of evoked potentials (EPs) is often used for the diagnosis of RRMS, although the possibility of applying EPs to the diagnosis of NMOSD has not been investigated in detail. Eighteen patients with NMOSD and 28 patients with RRMS were included in this study. The patients' neurological symptoms and signs were examined and their EPs were recorded. Characteristic findings were absence of visual evoked potentials and absence of motor evoked potentials in the lower extremities in patients with NMOSD, and a delay in these potentials in patients with RRMS. Most patients with NMOSD did not present abnormal subclinical EPs, whereas many patients with RRMS did. None of the patients with NMOSD showed abnormalities in auditory brainstem responses. NMOSD can be differentiated from RRMS by EP data obtained in the early stages of these diseases.

Longitudinal assessment of brainstem reflexes in Multiple Sclerosis compared to multimodal evoked potentials, MRI and clinical evaluations

Background We have previously shown in patients with relapsing-remitting Multiple Sclerosis (MS) that: ( i ) the vestibulomasseteric (VMR), acousticmasseteric (AMR), trigeminocollic (TCR) and vestibulocollic (VCR) reflexes are able to spot brainstem (BS) dysfunctions undetected by clinical and MRI examinations; (ii) the combined use of these Brainstem Reflexes (BSRs) with multimodal Evoked Potentials (EPs) is more valuable than each single test in the early years after onset. Our aim was to document BS changes over time by BSRs, EPs, MRI and BS signs/symptoms (CLIN) before and after at least one year follow up, in MS. Methods Forty-five MS patients (34.8 ± 8.6 yrs old; disease duration 8.9 ± 6.6 yrs) underwent BSRs, EPs (namely Brainstem Auditory Evoked Potentials – BAEPs, median and tibial Somatosensory Evoked Potentials-mSEPs and tSEPs), MRI and CLIN examination. BSR and EP data were ranked and summed up to obtain a cumulative score expressing severity of neurophysiological impairment. Before-after changes were tested with Wilcoxon test. Results After 15.1 ± 4.2 months from initial evaluation, no relapses had been reported by any patient. This was in line with the stability of the frequency of CLIN and MRI abnormalities (37.3% and 71.1%, respectively) at the follow up. Despite this, BSRs and EPs revealed a worsening of BS function. In particular, although the proportion of altered BSRs did not change significantly (80.6% vs 90.3%; p = 0.180), a significant worsening of scores was observed for VMR ( p = 0.001), AMR (0.018) and TCR ( p = 0.013). Similarly to BSRs, the incidence rate of EP abnormalities did not increased significantly (84.4% vs 86.7%, p = 0.564), but the analysis of cumulative score showed a significant worsening for the whole EP set ( p = 0.03) as well as for median SEP (68.9% vs 75.6%, p = 0.03), P14 mSEP (33.3% vs 51.1%, p = 0.005), tibial SEP (60% vs 66.7%, p = 0.03). Conclusions BSRs and EPs were able to reveal a significant worsening of BS functions in spite of any variation of both BS signs/symptoms and of MRI BS lesion load. This is in agreement with previous reports on BSR/EP ability to detect clinically and radiologically silent BS lesions. Further studies are needed in a larger cohort of patient to assess BSR clinical usefulness in a longitudinal perspective. FISM GRANT 2011/R/17.

Assessment of brainstem reflexes improves the diagnostic sensitivity of multimodal evoked potentials, MRI and clinical testing in the investigation of brainstem function in multiple sclerosis

Background Brainstem (BS) functions are conventionally studied by multimodal evoked potential (EP) recordings, MRI and clinical examination (CLIN). In Multiple Sclerosis (MS), increasing evidence accounts for a BS involvement, often undetected by standard testing. Recently, brainstem reflexes (BSRs) have drawn attention in evaluating BS dysfunction in MS especially the vestibulocollic (VCR) and vestibuloocular reflexes. In contrast, the vestibulomasseteric (VMR), acousticmasseteric (AMR) and trigeminocollic (TCR) reflexes have never been studied systematically in MS. Aims: to investigate whether the diagnostic sensitivity of CLIN, EPs and MRI can be improved adding the assessment of VMR, AMR, TCR and VCR either as single reflexes or in a 4-BSR battery. Methods The 4-BSR battery was recorded in 60 patients (33.3 ± 8.3 yrs) with relapsing-remitting MS (illness duration 8.2 ± 6.4 yrs). EP set included standard BAEPs, median and tibial SEPs Conventional MRI scans were focused on the BS lesion load. Group differences and correlations between variables were analysed with Mann–Whitney U test and Mc Nemar test. Results Distribution of BSR and EP abnormality frequencies in MS was: VMR 62.1%, AMR 55.1%, TCR 58.6%, VCR 25.9%; BAEPs 37.3%, median SEPs 60.3% and tibial SEPs 58.6%. Overall, BS dysfunction was detected as follows: BSRs 86.9%, EPs 82.7%, MRI 71.7%, CLIN 37.7%. While the performance of BSRs and EPs, taken separately, was not significantly higher than that of combined MRI/CLIN testing (70%), the paired use of BSRs/EPs had a sensitivity of 93.3%, which was significantly superior (p = 0.007), in a subset of patients with a disease duration ⩽6.4 yrs. Conclusions BSRs revealed brainstem lesions otherwise undetected by CLIN and MRI, thus providing additional evidence of BS dysfunction in MS. Noteworthy, BSRs could effectively complement the usual EP testing in early detection of clinically and radiologically silent lesions. This may encourage EPs/BSRs paired use in newly diagnosed. FISM GRANTS 2008/R/9 and 2011/R/17.

Brainstem auditory and somatosensory evoked potentials in relation to clinical and neuroimaging findings in Chiari type 1 malformation.

The aim of this study was to describe the abnormalities found in the recordings of evoked potentials (EPs), in particular those of brainstem auditory evoked potentials and somatosensory evoked potentials, in a homogeneous series of patients with Chiari type 1 malformation (CM-1) and study their relationship with clinical symptoms and malformation severity. CM-1 is characterized by cerebellar tonsils that descend below the foramen magnum and may be associated with EP alterations. However, only a small number of authors have described these tests in CM-1, and the patient groups studied to date have been small and heterogeneous. The clinical findings, neuroimages, and EP findings were retrospectively studied in a cohort of 50 patients with CM-1. Seventy percent of patients had EP abnormalities (brainstem auditory evoked potential: 52%, posterior tibial nerve somatosensory evoked potential: 42%, and median nerve somatosensory evoked potential: 34%). The most frequent alteration was an increased central conduction time. Morphometric measurements differed between the normal and pathological groups, although no statistical significance was found when comparing these groups. A high percentage of patients with CM-1 show EP alterations regardless of their clinical or radiological findings, thus highlighting the necessity of performing these tests, especially in patients with few or no symptoms.

Evoked potentials N200/P300 disorders and clinical phenotype in Cuban families with paranoid schizophrenia: a family-based association study

N200 and P300 event-related evoked potentials provide sensitive measurements of sensory and cognitive function and have been used to study information processing in patients with schizophrenia and their unaffected first-degree relatives. Reduced amplitude and increased latency of N200 and P300 potentials have been consistently reported in schizophrenia. Thus, event-related evoked potentials abnormalities are promising possible biological markers for genetic vulnerability to schizophrenia. To assess the association of changes in latency, amplitude and topographic distribution of potentials N200 and P300 of patients with paranoid schizophrenia and their healthy first-degree relatives, in families with schizophrenia multiplex. We measured latency and amplitude of the N200 and P300 component of evoked potentials using an auditory odd-ball paradigm in 25 schizophrenic patients (probands) from 60 families multiply affected with paranoid schizophrenia, 23 of their non-schizophrenic first-degree relatives and 25 unrelated healthy controls, through a study of family association. Schizophrenic patients and their relatives showed significant latency prolongation and amplitude reduction of the N200 and P300 waves compared to controls. Left-temporal as compared to right-temporal N200 and P300 were significantly smaller in schizophrenic patients and their non-schizophrenic first-degree relatives than in controls. Our results suggest that event-related evoked potentials abnormalities may serve as markers of genetic vulnerability in schizophrenia. Confirming results of other researchers, this present study suggests that latency prolongation and amplitude reduction of the N200 and P300 waves and an altered topography at temporal sites may be a trait “marker” of paranoid schizophrenia.

Clinical neurophysiological assessment of sepsis-associated brain dysfunction: a systematic review.

IntroductionSeveral studies have reported the presence of electroencephalography (EEG) abnormalities or altered evoked potentials (EPs) during sepsis. However, the role of these tests in the diagnosis and prognostic assessment of sepsis-associated encephalopathy remains unclear.MethodsWe performed a systematic search for studies evaluating EEG and/or EPs in adult (≥18 years) patients with sepsis-associated encephalopathy. The following outcomes were extracted: a) incidence of EEG/EP abnormalities; b) diagnosis of sepsis-associated delirium or encephalopathy with EEG/EP; c) outcome.ResultsAmong 1976 citations, 17 articles met the inclusion criteria. The incidence of EEG abnormalities during sepsis ranged from 12% to 100% for background abnormality and 6% to 12% for presence of triphasic waves. Two studies found that epileptiform discharges and electrographic seizures were more common in critically ill patients with than without sepsis. In one study, EEG background abnormalities were related to the presence and the severity of encephalopathy. Background slowing or suppression and the presence of triphasic waves were also associated with higher mortality. A few studies demonstrated that quantitative EEG analysis and EP could show significant differences in patients with sepsis compared to controls but their association with encephalopathy and outcome was not evaluated.ConclusionsAbnormalities in EEG and EPs are present in the majority of septic patients. There is some evidence to support EEG use in the detection and prognostication of sepsis-associated encephalopathy, but further clinical investigation is needed to confirm this suggestion.

P06. Prognostic value of multimodal neurophysiological testing in spinal cord injury

The disability secondary to traumatic spinal cord injury (SCI) is known to be highly variable among patients due to the vast variety of lesion levels and varying severity, resulting in a mixture of central and peripheral neural lesion burden. In this context prognostication of outcome becomes a challenge, yet is paramount in planning rehabilitation and clinical trials. Next to clinical assessment by International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI) neurophysiological techniques have been used for diagnosing lesion severity and prognostication as they are objective and early available. Evoked potentials (EPs) have been suggested as diagnostic and prognostic tools in SCI, although their importance and prognostic value has not been completely established. Prognostic significance of multimodal EPs was assessed in a cohort of 633 SCI cases from the European Multicenter Study about Spinal Cord Injury database (EMSCI, www.emsci.org ). SCI patients underwent complete neurophysiological evaluation (NPE) prospectively, including nerve conduction studies, somatosensory and motor EPs within 4 weeks after spinal injury. Functional recovery after SCI as the endpoint was assessed at 3, 6 and 12 months during and after rehabilitation by standardized and validated testing using the international Spinal Cord Independence Measure (SCIM). EPs abnormalities were quantified through an index of global EPs alteration (EP score). The relationship between EP score and disability in SCIM was analyzed by Spearman ρ correlation coefficient. Receiver operated characteristic (ROC) curves were used to determine best EP score cut off values to predict SCIM endpoints within sub-score categories such as mobility and hand function. Significant correlations could be shown between EP score (motor and somatosensory EPs) and SCIM score at the time of NPE and at 3, 6 and 12 months of follow-up. Goodness of fit increased over time indicating true predictive value of early EP assessment for late functional outcome. For each functional sub-score endpoint, significant sensitivity, specificity, positive and negative predictive values were obtained. Multimodal EPs are valuable objective procedures to predict disability in traumatic SCI patients. This prediction can be achieved independent of clinical assessment (ISNCSCI) and without knowledge of lesion level.

7. Evoked potentials in diagnosis and prognosis of multiple sclerosis

Objective Evoked potentials (EP) are functional neurophysiological methods that have been used in multiple sclerosis (MS) especially in its early diagnosis. Recently, multimodal EPs appears to be a prognostic factor for disease progression. Methods The review is based on a literature search in PubMed and the author’s long experience of neurophysiological diagnostics. Results Visual evoked potential (VEP) are preferentially used in early diagnosis of MS. They are highly sensitive to detect subclinical optic neuritis more than magnetic resonance. Somatosensory (SEP) and motor (MEP) evoked potentials can reveal subclinical lesions in the central nervous system and could be a supplementary diagnostic tests for sensory and motor system disturbances. MEP abnormalities correlate with the degree of motor impairment and disability assessed by EDSS. Abnormal multimodal EPs (”positive EP score”) at the first session are worse prognostic factor. Low and stable EP scores along with stable EDSS identify a ”benign” form of RS. The assessment of the disease progression and/or monitoring of the therapeutic effects have some limitations, e.g. abnormal response persists even in relative inactivity of the disease and it’s localization is non-specific. The sensitivity of EPs increases with the length of the tested neural pathways and with used EP modalities. Conclusion Evoked potentials are highly sensitive in revealing ”silent lesions” especially at the beginning of MS and/or when no obvious neurological symptoms occur. Multimodal evoked potentials have indisputable benefit of prognostic value to determine non-responders, ”benign” course of the disease and patients with significant disease progression. Supported by Research Project of Charles University PRVOUK P34, Czech Republic.

EEG, evoked potentials and pulsed Doppler in asphyxiated term infants

ObjectiveTo evaluate electroencephalograms (EEG), evoked potentials (EPs) and Doppler findings in the cerebral arteries as predictors of a 1-year outcome in asphyxiated newborn infants. MethodsEEG and EPs (brain stem auditory (BAEP), somatosensory (SEP), visual (VEP) evoked potentials) were assessed in 30 asphyxiated and 30 healthy term infants during the first days (range 1–8). Cerebral blood flow velocities (CBFV) were measured from the cerebral arteries using pulsed Doppler at ∼24h of age. EEG, EPs, Doppler findings, symptoms of hypoxic ischemic encephalopathy (HIE) and their combination were evaluated in predicting a 1-year outcome. ResultsAn abnormal EEG background predicted poor outcome in the asphyxia group with a sensitivity of 67% and 81% specificity, and an abnormal SEP with 75% and 79%, respectively. Combining increased systolic CBFV (mean+3SD) with abnormal EEG or SEP improved the specificity, but not the sensitivity. The predictive values of abnormal BAEP and VEP were poor. Normal EEG and SEP predicted good outcome in the asphyxia group with sensitivities from 79% to 81%. The combination of normal EEG, normal SEP and systolic CBFV<3SD predicted good outcome with a sensitivity of 74% and 100% specificity. ConclusionsCombining abnormal EEG or EPs findings with increased systolic CBFV did not improve prediction of a poor 1-year outcome of asphyxiated infants. Normal EEG and normal SEP combined with systolic CBFV<3SD at about 24h can be valuable in the prediction of normal 1-year outcome. SignificanceCombining systolic CBFV at 24h with EEG and SEP examinations can be of use in the prediction of normal 1-year outcome among asphyxiated infants.

The utility of multimodal evoked potentials in multiple sclerosis prognostication

The ability to predict disability development in multiple sclerosis (MS) is limited. While abnormalities of evoked potentials (EP) have been associated with disability, the prognosticating utility of EP in MS remains to be fully elucidated. The present study assessed the utility of multimodal EP as a prognostic biomarker of disability in a cohort of clinically heterogeneous MS patients. Median and tibial nerve somatosensory, visual, and brainstem auditory EP were performed at initial assessment on 63 MS patients (53 relapsing–remitting and 10 secondary progressive) who were followed for an average of 2years. A combined EP score (CEPS) was calculated consisting of the total number of abnormal EP tests, and was correlated with the Expanded Disability Status Scale (EDSS) at baseline and follow-up. There was a significant correlation between multimodal EP and baseline and follow-up EDSS. Specifically, tibial nerve P37 latencies correlated with EDSS (RBASELINE=0.49, p<0.01; RFOLLOW-UP=0.47, p<0.01), as did the median nerve N13 (RBASELINE=0.40, p<0.01; RFOLLOW-UP=0.35, p<0.05) and N20 latencies (RBASELINE=0.43, p<0.01; RFOLLOW-UP=0.47, p<0.01), and P100 full-field (RBASELINE=0.50, p<0.001; RFOLLOW-UP=0.45, p<0.001) and central field latencies (RBASELINE=0.60, p<0.001; RFOLLOW-UP=0.50, p<0.001). In addition, there was a significant correlation between the CEPS with baseline (R=0.65, p<0.001) and follow-up (R=0.57, p<0.01) EDSS. In contrast, white matter disease burden, as measured by T2 lesion load, exhibited a weaker correlation with EDSS (RBASELINE=0.28, p<0.05). In conclusion, these findings suggest that abnormalities of EP, as quantified by the novel CEPS, may be a useful biomarker for prognosticating clinical disability in MS, and may aid in the quantification of MS disease severity and in guiding therapeutic decisions.

Brain-stem auditory evoked responses in COPD patients

BackgroundCOPD is a multi-system disorder. It appears to be associated with the presence of systemic inflammatory markers as C reactive protein. Aim of the workThe present study aimed to evaluate the brain-stem auditory evoked potentials (BAEP) abnormalities in stable COPD patient and its correlation with high sensitivity C reactive protein (hs-CRP) as a part of multi-system disorder. Subjects and methodsThis case control study was carried out at Mansoura University Hospital Egypt from October 2009 to February 2010. The study comprised 40 stable COPD patients and 15 healthy controls with no risk that may lead to neuropathy. All the patients and controls were subjected to the following: I-Thorough history taking and clinical examination. II-Pulmonary function tests including: 1-Spirometry 2-Body plethsymography 3-Arterial blood gases analysis. III- Record of brain-stem auditory evoked potentials (BAEP) including: latencies of waves I, II, III, IV and V together with interpeak latencies (IPLs) of I–III, I–V and III–V and amplitudes of waves I–Ia and V–Va. IV–Measurement of serum high sensitivity C reactive protein (hs-CRP) by ELISA technique. V–Statistical analysis. ResultsThe level of hs-CRP reactive protein in COPD was significantly elevated and correlated with spirometric, blood gases parameters and GOLD stage. The BAEP latencies of waves I, II, III, IV and V, together with interpeak latencies and amplitudes of waves I–Ia and V–Va measured on both ears were significantly different in COPD patients than controls. The prevalence of brain-stem auditory evoked potentials abnormalities was higher among very severe group of COPD. Most of BAEP wave latencies together with interpeak latencies and wave amplitudes on both ears were significantly correlated with the spirometric and blood gases parameters. The level of hs-CRP was correlated significantly with abnormalities of BAEP variables. ConclusionThis study showed significant subclinical BAEP abnormalities in studied stable COPD male patients. This indicates conductive defect of auditory nerve, cochlea and even hearing pathway in the brain as a part of systemic inflammation.Theses BAEP abnormalities were significantly correlated with GOLD classification, hs-CRP and PaO2.

Prognostic value of multimodal evoked potentials in multiple sclerosis: the EP score

Evoked potentials (EPs) have long been used as diagnostic tools in multiple sclerosis (MS), although their importance decreased as magnetic resonance imaging (MRI) became available. However, the prognostic value of EPs in MS has not been completely established. The aim of the study was to analyze the prognostic significance of EPs in a cohort of MS cases. From the Verona University Hospital MS Clinic database we retrospectively identified 80 MS patients who underwent a complete neurophysiological evaluation, including visual, brain stem, somatosensory and motor EPs and who were followed for at least 5 years after the study. EPs abnormalities were quantified through an index of global EPs alteration (EP score). The relationship between EP score and disability in terms of Expanded Disability Status Scale (EDSS) was analyzed by the Kaplan-Meier survival method and Spearman ρ correlation coefficient. ROC curves were used to determine the best EP score cut off to predict different EDSS endpoints. For each endpoint, sensitivity, specificity, positive and negative predictive value of EP score were calculated. We found a significant correlation (p < 0.001) between EP score and EDSS score at the time of neurophysiological study and at 1, 3 and 5 years of follow-up, particularly for motor and somatosensory EPs. Kaplan-Meier curves confirmed an increased risk of disability in those patients with EP score higher than the median value. EP score of 8 or 9 showed the highest sensitivity and specificity in predicting EDSS 4.0 and 6.0. EPs are reliable procedures to predict disability in MS patients. The correlation between EPs abnormalities and EDSS is higher than between conventional MRI and EDSS.

‘Weight of Evidence’ analysis of neonatal sensory evoked potentials

Abnormalities in neonatal sensory evoked potentials (EPs) may indicate a poor developmental prognosis, but such EPs are highly variable, changing with development, and requiring subjective analysis. ‘Weight of Evidence’ (W), the logarithm of the ratio of the probability that a response has occurred to the probability that it has not, and ‘Response Entropy’ (S), the spread of the response over time and frequency bands, might provide objective and quantitative measures of EP abnormalities and developmental changes, based on information processing characteristics. W and S were calculated from visual and somatosensory EPs recorded in 72 premature newborns over 2 sessions, separated by 6–9 weeks. Group 1 had normal brain ultrasound images at the time of recording, and a normal developmental outcome at age 2 years. Group 2 had abnormal brain ultrasound images but normal outcome. Group 3 had abnormal brain imaging and abnormal outcome.W values were lowest in Group 3 (visual p<0.001: somatosensory p<0.04). Entropy diminished between sessions (visual p<0.001: somatosensory p<0.015): it was highest in Group 2 (visual p<0.03). The low W in Group 3 implies a lower signal/noise ratio, reducing information capacity. Decreasing entropy suggests more efficient information encoding with maturation.

Analysis of abnormal motor evoked potentials of the obese subjects induced by magnetic stimulation at T12 to L1

Objective To study the abnormalities of motor evoked potentials(MEPs)obtained from obese subjects induced by magnetic stimulation at T12 to L1. Methods A total of 90 healthy subjects without any neuro-muscular system abnormalities were divided into 3 groups according to the body mass index(BMI).The control group consisted of 30 normal somatotype males(BMI 30)and weight-reduc-ing group(BMI>30)consisted of 30 obese somatotype males,respectively.The subjects in the control group and obese somatotype group maintain their usual lifestyle as before,while those in the weight-reducing group were reques-ted to lose weight by all means.MEPs were induced by using magnetic stimulation of 70%and 90%the output of the stimulator,respectively,at T12 to L1 and recorded from all the anbjcots at the time of admission to the study and one year later. Results At admission,the amplitude and conduction time of MEPs in obese somatotype group and weight-reducing group were significantly different from those in control group(P 0.05).One year later,the amplitude and conduction time of MEPs in obese somatotype group were significantly different from those in control group and weight-reducing group(P 0.05). Conclusion Supra-maximal magnetic stimulation should be used for recording the MEPs from the obese subjects,or false positive result would be obtained. Key words: Magnetic stimulation; Motor evoked potential; Obese subject

Consensus on the use of neurophysiological tests in the intensive care unit (ICU): Electroencephalogram (EEG), evoked potentials (EP), and electroneuromyography (ENMG)

To provide a consensus of European leading authorities about the optimal use of clinical neurophysiological (CN) tests (electroencephalogram [EEG]; evoked potentials [EP]; electroneuromyography [ENMG]) in the intensive care unit (ICU) and, particularly, about the way to make these tests clinically useful for the management of individual patients. This study gathered together several European clinical neurophysiologists and neurointensivists whose leading contributions in the adult or paediatric ICU and in continuous neuromonitoring had been peer-acknowledged. It was based on both a literature review and each participant's own experience. Given the methodological impossibility to gather studies fulfilling criteria of evidence-based medicine, this article essentially relies on expert opinions that were gained after several rounds, in which each expert was invited to communicate his own contribution to all other experts. A complete consensus has been reached when submitting the manuscript. What the group considered as the best classification systems for EEG and EP abnormalities in the ICU is first presented. CN tests are useful for diagnosis (epilepsy, brain death, and neuromuscular disorders), prognosis (anoxic ischemic encephalopathy, head trauma, and neurologic disturbances of metabolic and toxic origin), and follow-up, in the adult, paediatric, and neonatal ICU. Regarding prognosis, a clear distinction is made between these tests whose abnormalities are indicative of an ominous prognosis and those whose relative normalcy is indicative of a good prognosis. The prognostic significance of any test may vary as a function of coma etiology. CN provides quantitative functional assessment of the nervous system. It can be used in sedated or curarized patients. Therefore, it should play a major role in the individual assessment of ICU patients.