Abnormal SEP Research Articles

Somatosensory evoked potentials are abnormal with plagiocephaly

BackgroundDeformational plagiocephaly is usually managed conservatively, as it tends to improve over time and with the use of conservative measures. However, before the year 2017 we operated on patients with severe plagiocephaly and neurological symptoms at the Helsinki Cleft Palate and Craniofacial Center.MethodsOf the 20 infants with severe deformational plagiocephaly and neurological symptoms referred to us between 2014 and 2016, 10 underwent cranioplasty open reshaping of the posterior cranial vault. The parents of the last 10 patients were given information on the natural history of the condition and the patients were followed up with an outpatient protocol. The aim of this study was to gain information on the brain electrophysiology and recovery of patients after total cranial vault reconstruction by measuring the electroencephalogram (EEG) somatosensory evoked potentials (SEP; median nerve).ResultsOf the 10 participants in the operation arm, six had abnormal SEP at least on the affected cerebral hemisphere and all SEPs were recorded as normal when controlled postoperatively. In the follow-up arm, eight out of 10 participants had abnormal SEP at the age of approximately 24 months, and all had normalized SEPs at control visits.ConclusionOur data suggest that cranioplasty open reshaping of the posterior cranial vault did not affect abnormal SEP-EEG recordings. We have abandoned the operations in deformational plagiocephaly patients due to findings suggesting that expanding cranioplasty is not beneficial for brain function in this patient group.

Efficacy of multimodal intraoperative neurophysiology monitoring to distinguish the nervous system injury during surgery for chronic cervical compressive myelopathy

Objective To study the efficacy of intraoperative neuromonitoring with SEP, MEP and EMG to predict of spinal cord and nerve root injury during surgery for chronic cervical compressive myelopathy. Methods From October 2014 to June 2016, 107 patients (80 males, 27 females) who underwent surgery for chronic cervical compressive myelopathy and intra-operative neuromonitoring with SEP, MEP and EMG were enrolled in this study. The mean age was 53.36±11.35 years (24-79 years), and the mean follow-up time was 7.94±6.05 months (1-18 months). The monitoring method, abnormal alarm, treatment and outcome of intraoperative SEP, MEP and EMG were recorded in all patients. The preoperative, postoperative and last follow-up neurologic functions were compared. True positive, false positive, true negative and false negative cases were collected in all patients. Sensitivity, specificity, positive predictive value and negative predictive value were calculated, and the utility of monitor spinal cord and nerve root injury was analyzed. Results SEP, MEP and EMG baseline values of 107 patients were established at the end of exposure. A total of 8 patients with intraoperative neurophysiology monitoring were abnormal (4 cases of anterior surgery, 4 cases of posterior surgery), including 1 case with abnormal SEP and MEP, but EMG was normal, he became incomplete paralysis postoperatively; 4 cases with abnormal MEP and EMG, but SEP was normal, they suffered C5 nerve root palsy postoperatively; 2 cases with abnormal MEP, while SEP and EMG were normal, one was C5 nerve root palsy and another was incomplete paralysis for the right side of the limb postoperatively; 1 case with abnormal EMG, but SEP and MEP were normal, he was C5 nerve root palsy postoperatively. 1 patient with anterior surgery was false negative of intraoperative neurophysiology monitoring, it was not found abnormal during surgery, but the patient was C5 nerve root palsy after operation. The utility of monitor spinal cord injury, the sensitivity and specificity of SEP was 50% and 100%, respectively. The positive predictive value was 100% and the negative predictive value was 99.06%. The sensitivity and specificity of MEP were 100%, positive predictive value and negative predictive value were 100%. The effect of monitor nerve root injury, the sensitivity and specificity of SEP was 0 and 100%, respectively. The positive predictive value was 0 and the negative predictive value was 93.46%. The sensitivity and specificity of MEP was 71.43% and 100%, respectively. The positive predictive value was 100% and the negative predictive value was 98.04%. The sensitivity and specificity of EMG sensitivity was 71.43% and 100%, respectively. The positive predictive value was 100% and the negative predictive value was 98.04%. Conclusion During operation of chronic cervical compressive myelopathy, SEP and MEP for spinal cord injury monitoring, and MEP and EMG for nerve root injury monitoring were effective ways to promise comprehensive monitor the spinal cord and nerve root system. Key words: Cervical vertebrae; Spinal cord compression; Evoked potentials, somatosensory; Evoked potentials, motor; Electromyography

The correlation factor analysis for conversion of clinically isolated syndrome to multiple sclerosis and neuromyelitis optica

To analyze the features of patients who converted from clinically isolated syndrome (CIS) to multiple sclerosis (MS) and neuromyelitis optica (NMO) and explore the correlated factors. A total of 151 patients admitted in our unit as CIS from January 2009 to December 2014 were enrolled in the study. All patients were divided into the following four groups by locations of the initial lesion, which were the spinal cord, the optic nerve, the brain stem and the multifocal lesions. Data were collected at the baseline including demographics, expanded disability status scale (EDSS) score, site of CIS, presence or absence of cerebrospinal fluid (CSF) oligoclonal bands (OB) and serum aquaporin-4 antibody (AQP4-Ab), evoked potential (EP) and MRI lesions. The conversion rates from CIS to clinically definite MS or NMO were calculated and the correlated factors were explored. With a mean follow-up period of (44.11±17.62)months, 46/151(30.5%) patients converted to MS, 28/151 (18.5%) to definite NMO and 66/151 patients(43.7%)remained as CIS. Other patients were converted to optic neuritis(4/151), one-time transverse myelitis(3/151), acute disseminated encephalomyelitis (1/151) and Balo concentric sclerosis(3/151) . The EDSS score was significantly higher in patients converted to NMO than those converted to MS (P=0.003). The initial manifestation of optic neuritis significantly correlated with the conversion to NMO (P=0.000), while the initial manifestation of CIS with multifocal lesions significantly correlated with the conversion to MS (P=0.000). Neither the isolated BAEP (P=0.703), VEP (P=0.076), SEP (P=0.915) nor the combination of two (P=0.546)or three (P=1.000) of the above parameters could help to distinguish the conversion to MS or NMO. More patients with positive CSF-OB converted to MS (P=0.001), while more patients with positive serum AQP4-Ab converted to NMO (P=0.001). More patients were serum AQP4-Ab positive in those converted to NMO than those converted to MS (P=0.000). Lesions longer than three vertebral segments were dominant in patients converted to NMO (P=0.000). The logistic regression analysis revealed that factors correlated with conversion from CIS to MS were the initial CIS manifestation of multifocal lesions (OR=4.775, P=0.002), positive CSF-OB (OR=7.794, P=0.002) and VEP abnormality (OR=7.251, P=0.001). Factors correlated with conversion from CIS to NMO were female in gender (OR=12.536, P=0.019), positive serum AQP4-Ab (OR=36.410, P=0.002), lesions longer than three vertebral segments (OR=93.602, P=0.001), abnormal VEP and SEP (OR=18.448, P=0.002; OR=12.731, P=0.016). Factors correlated with the conversion from CIS to MS are initial CIS manifestation of multifocal lesions, positive CSF-OB and abnormal VEP, while those correlated with the conversion from CIS to NMO are female in gender, positive serum AQP4-Ab, initial CIS manifestation with optic nerve, lesions involved more than three vertebral segments and abnormal VEP and SEP.

Somatosensory Evoked Potentials Study in Cervical Spondylotic Myelopathy Patients

Background: Cervical spondylotic myelopathy (CSM) is considered the most serious consequence of cervical spondylosis and accounts for the majority of non_traumatic paraparesis and/or quadriparesis. The electrical property of the spinal cord and its susceptibility to injuries renders electrophysiology relevant to the management of CSM. Somatosensory evoked potentials study (SEPs) is an objective assessment of the functional integrity of the neural pathway.Objective: Utilizing both of the median and the posterior tibial SEPs in evaluating the functional integrity of the cervical spinal cord in patients with CSM and to correlate the SEPs findings with the clinical and MRI findings.Patients and methods: Twenty two patients with CSM (11 male and 11 female) ranging in age from 29 to 77 years with a mean age of (56 ±11) years and matched with 25 healthy subjects of the control group were enrolled in this study.Results: In this study, 86.36% of patients had abnormal SEPs study (either tibial or median or both tests abnormal), with 68.2% abnormal tibial and 63.6% abnormal median. There was no difference between right and left side study of neither median nor tibial SEPs studies (P>0.05). Loss of N13, loss or delayed N20 and loss or delayed N13-N20 were the most frequent abnormalities for median SEPs and loss or delayed P37 and LP-P37 were most frequent abnormalities in tibial SEPs. Results showed that normal SEPs findings mostly correlated with mild and early myelopathy (grade-1 and grade-2 Nurick). Abnormal SEPs findings are useful in prediction the progression of myelopathy in patients with mild clinical neurological deficits in the early stages of the disease.Conclusion: This study concluded that both median and tibial SEPs montages are useful important objective assessment of the spinal cord function to evaluate patients with CSM since MRI and SEPs may evaluate different aspects of the disease process.

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.

Delayed Onset of Thoracic SCIWORA in Adults

Spinal cord injury (SCI) without radiographic abnormality (SCIWORA) is estimated to account for 1-9% of the occurrence of SCI. Of these, cervical SCIWORA in children is common, but thoracic SCIWORA delayed onset in adult is much less common. We experienced a case of 38-years old male patient with lower extremity weakness; he had fallen down a week earlier before the investigation. At the time of admission, motor grade was 4 with voiding incontinence and ambulated with cane. He presented progressive weakness from G4 to G3 and hypoesthesia was below T8 dermatome and ambulated with wheelchair. Whole spine and lumbar MRI findings showed no abnormality and electrodiagnostic findings showed normal NCS, however, abnormal SEP on both the tibial nerves. After steroid therapy and proper rehabilitation program for 2 weeks, lower extremity strength was improved from G4 to G3, voiding was continent, and ambulation reached cane gait.

Electrophysiological findings in neurofibromatosis type 1

Neurofibromatosis type 1 (NF1) is a common, autosomal dominant neurocutaneous disorder in which any organ system, including the skin, skeleton and nervous system can be affected. In this study, we compared the electrophysiological and magnetic resonance imaging (MRI) findings in patients with NF1. Thirty-nine adolescent and adult patients (23 women and 16 men) diagnosed with NF1 with a mean age of 25.8 ± 10 years (10–56) were included in this study. We collected data in the form of the results of neurological examinations, multimodal evoked potentials (EPs; brainstem auditory evoked potentials, BAEPs; somatosensory evoked potentials, SEPs; and visual evoked potentials, VEPs), cerebral/orbital/spinal MRIs, and electroneuromyography (ENMG). Twenty (51.3%) patients showed abnormal VEPs, 14 (35.9%) showed abnormal SEPs, and six (15.4%) showed abnormal BAEPs. All evoked potentials were abnormal in four (10.3%) cases. These electrophysiological findings occurred primarily in the absence of any clinical sign related to the affected system. MRI revealed pathologic findings in 26 of 39 patients, and these were not always correlated with visual, auditory, or somatosensory pathway abnormalities. ENMG showed polyneuropathy in two of 33 patients who underwent ENMG. Our study showed that MRI and electrophysiological abnormalities may be found in most patients with NF1, even in the absence of associated clinical symptoms or signs. Electrophysiological testing is helpful for monitoring the subclinical involvement of the central and peripheral nervous systems in patients with NF1.

The Characteristics of Gait Disturbance and Its Relationship with Posterior Tibial Somatosensory Evoked Potentials in Patients with Cervical Myelopathy

Prospective case control study. This study is to investigate the gait characteristics of cervical myelopathy (CM) and to assess the relationship between presence of abnormality of posterior tibial somatosensory evoked potential (PTSEPs) and gait parameters. Many of CM patients suffer from gait disturbance so that the assessment of walking ability and its restoration are one of main concerns. The patients were recruited who had suffered from gait disturbance and were diagnosed as CM by cervical magnetic resonance image (MRI). All subjects underwent three-dimensional gait analysis and PTSEP. Normal persons were recruited as control groups and underwent gait analysis. The CM patients were divided into two groups such as normal and abnormal SEP groups, and two groups were compared as to presence of signal change in MRI and gait parameters. CM groups revealed significantly lower gait velocity, decreased step length and stride length, and increased double support time. They showed significantly decreased maximal knee flexion angle in swing phase, the decreased plantarflexion angle at push off, and the increased maximal dorsiflexion angle at swing phase in comparison with control group. Abnormal SEP group demonstrated the lower gait velocity and cadence, smaller plantarflexion angle at push off and the larger maximal dorsiflexion angle at swing phase in comparison with normal SEP group. There was no significant relationship between presence of SEP abnormality and signal change of MRI. CM patients compensated stabilizing balance by decreasing gait velocity and step length as well as increasing step width and double support time. Considering the presence of abnormality of PTSEP was closely related to typical gait characteristics of CM patient, the gait deviation of CM patients was attributed to impaired proprioception of lower limbs and poor stability.

Clinical and laboratory characteristics of atopic myelitis: Korean experience

HyperIgEemia and atopy have recently been reported to be related to various neurological diseases such as Hirayama disease and idiopathic myelitis. The aims of this study are to determine frequency of atopy or hyperIgEemia in idiopathic myelitis and to characterize the clinical and laboratory profiles of atopic myelitis (AM). From January 2006 to August 2008, 29 consecutive patients with idiopathic myelitis were recruited. We compared demographic data, laboratory results and radiologic findings between patients with atopic diathesis and those without. Allergic or atopic history was found in only 4 patients (13%), but hyperIgEemia and mite antigen-specific IgE were observed in 17 (58%) and 19 (65%) of idiopathic myelitis patients, respectively. Patients with AM ( n = 14, 48%) showed the following distinctive features: (1) younger age at onset, (2) non-acute onset and long duration of symptoms at admission, (3) predominant sensory symptoms with mild weakness, (4) low EDSS score, (5) low frequency of abnormal SEP findings, and (6) increased eosinophils in peripheral blood. Common MR findings of AM included eccentric lesions occupying more than two-thirds of spinal cord with focal peripheral enhancement on axial image. These lesions were usually extended over more than 3 to 5 vertebral segments with cord swelling. HyperIgEemia and mite antigen-specific IgE are fairly common in idiopathic myelitis patients. The AM patients show relatively homogenous clinicolaboratory and radiological features. It is noteworthy that none of these patients showed brain abnormalities suggestive of multiple sclerosis or neuromyelitis optica (NMO).

128-Channel somatosensory evoked potentials in the differential diagnosis of parkinsonian disorders

Purpose The differential diagnosis of parkinsonian disorders can be very difficult, especially at an early stage. In this study, we investigated whether SEP amplitude recorded by 128-channel EEG is useful for diagnosis of parkinsonian disorders, and in particular whether SEP asymmetry can differentiate corticobasal degeneration (CBGD) from other parkinsonian disorders. Methods We recorded median nerve SEPs in 47 patients suspected of CBGD, supranuclear palsy or definite Parkinson's disease at an early stage. We compared SEP asymmetry and parietal peak amplitudes of the patients after grouping them based on their clinical diagnosis after 1–5 years of follow-up. In nine subjects the diagnosis remained unclear. Results Three of 13 patients with a clinical diagnosis of CBGD had an abnormal SEP asymmetry. Furthermore, we found extremely high N20 amplitudes in three other patients with CBGD. However, similar asymmetry abnormalities were found in patients with other Parkinsonian disorders. Conclusion Despite the use of 128-channel SEP recordings and analysis techniques, which are more accurate than conventional techniques, sensitivity and specificity of cortical median nerve SEP asymmetry and parietal amplitude for differentiating CBGD from other parkinsonian disorders were low at an early stage of the disease. A possible reason for this may be that the hand area of the primary somatosensory cortex was not yet affected in most CBGD patients.

Early abnormalities of evoked potentials and future disability in patients with multiple sclerosis

Evoked potentials (EP) have a role in making the diagnosis of multiple sclerosis (MS) but their implication for predicting the future disease course in MS is under debate. EP data of 94 MS patients examined at first presentation, and after five and ten years were retrospectively analysed. Patients were divided into two groups in relation to the prior duration of disease at the time point of first examination: group 1 patients (n-44) were first examined within two years after disease onset, and group 2 patients (n-50) at later time points. As primary measures sum scores were calculated for abnormalities of single and combined EP (visual (VEP), somatosensory (SEP), magnetic motor evoked potentials (MEP)). In patients examined early after disease onset (group 1), a significant predictive value for abnormal EP was found with MEP and SEP sum scores at first presentation correlating significantly with Expanded Disability Status Scale (EDSS) values after five years, while the VEP sum score was not. The cumulative number of abnormal MEP, SEP and VEP results also indicated higher degrees of disability (EDSS≥ 3.5) after five years. Combined pathological SEP and MEP findings at first presentation best predicted clinical disability (EDSS≥ 3.5) after five years (odds ratio 11.0). EP data and EDSS at first presentation were not significantly linked suggesting that EP abnormalities at least in part represented clinically silent lesions not mirrored by EDSS. For patients in later disease phases (group 2), no significant associations between EP data at first presentation and EDSS at five and ten years were detected. Together with clinical findings and MR imaging, combined EP data may help to identify patients at high risk of long-term clinical deterioration and guide decisions as to immunomodulatory treatment.

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.

Brain damage in glycogen storage disease type I

Objective To investigate brain morphology and function in patients with glycogen storage disease type I (GSDI). Study design Nineteen patients (13 females and 6 males, aged 0.9-22.6 years) and 38 sex- and age-matched controls entered the study. Neurological examinations, psychometric tests (IQ, tests of performance and verbal abilities), standard electroencephalogram (EEG), somatosensory (SEPs), visual (VEPs), and brain-stem auditory evoked potentials (BAEPs), and brain magnetic resonance imaging (MRI) were performed. Results The results of tests of performance ability were lower in patients than in controls ( P < .05). The prevalence of abnormal EEG findings (26.3% versus 2.6%), VEPs (38.4% versus 7.7%), SEPs (23.0% versus 0%), and BAEPs abnormalities (15.7% versus 0%) was higher in patients than in controls ( P < .05). MRI pattern was altered in 57.1% of patients and was normal in all controls ( P < .05). Both results of tests of performance ability and BAEPs abnormalities significantly correlated with the frequency of admissions for hypoglycemia, whereas EEG abnormalities correlated with dietary compliance ( P < .05). Conclusions Brain damage, probably caused by recurrent severe hypoglycemia, may be present in patients with GSDI.

Abnormal somatosensory evoked potentials indicate compressive cervical myelopathy in mucopolysaccharidoses.

Compressive myelopathy at the cranio-cervical junction is a complication of mucopolysaccharidoses (MPS). To detect cervical myelopathy we recorded median and posterior tibial nerve SEPs in 15 patients aged 2.4-33.4 years (median 8.8 years) with MPS I-S (n = 3), MPS IVA (n = 8) and MPS VI (n = 4). In addition to the cortical waveforms we recorded the subcortical median nerve SEPs N13b and P13 generated near the cranio-cervical junction and the lemniscal P30 after posterior tibial nerve stimulation. MRI studies in 13 subjects revealed spinal cord compression at the cranio-cervical junction in 10 patients; 5 patients had an increased signal intensity on the T2-weighted initial MRI indicating high cervical myelomalacia and 4 patients had clinical signs of cervical myelopathy. We did not find a relationship between the SEPs and spinal cord compression. Abnormal SEPs were found in the patients with MRI evidence of myelomalacia (sensitivity 1.0, specificity 1.0) and correspondingly in the patients with clinical signs (sensitivity 1.0, specificity 0.91). The SEPs consequently deteriorated in 2 subjects of 7.3 and 10.3 years of age. Abnormal SEPs indicated subclinical cervical myelopathy in 3 subjects. Cervical cord compression may be present before occurrence of clinical or electrophysiological evidence of myelopathy. However, we feel that the SEP analysis is useful to detect functional impairment of the cervical cord in patients with MPS.

Guamanian neurodegenerative disease: electrophysiologic findings.

Amyotrophic lateral sclerosis (ALS), parkinsonism and/or dementia are highly prevalent among the Chamorro population of Guam. The incidence of Guamanian ALS has markedly declined in recent years, but these incidence figures may reflect underascertainment of subclinical disease. Guamanian Chamorro patients have not been systematically studied using modern clinical neurophysiological techniques. Electromyography (EMG: needle exam and nerve conduction studies) was used to study 29 patients with the major subtypes of Guamanian neurodegenerative disease, as well as 11 neurologically normal Guamanian Chamorro subjects. Central conduction was assessed by somatosensory evoked potentials (SEP's) in 16 patients. EMG evidence of peripheral neuropathy, (often subclinical) was found in 45% of Guamanian patients but no Chamorro control subjects. Diabetes mellitus, which is highly prevalent in this population, was present in some, but not all of these cases. Clinically unsuspected motor neuron disease was identified by EMG in only one of the 23 Guamanian patients with parkinsonism and/or dementia and in none of the 11 Chamorro control subjects. Two of seven patients with the clinical phenotype of Guamanian ALS had a more benign EMG pattern on the needle electrode exam with absence of fibrillation and fasciculation potentials. Three of 16 patients (all with parkinsonism and dementia) had mildly abnormal tibial SEP's. No patient had EMG evidence of myopathy or a defect of neuromuscular transmission. We conclude: (1) peripheral neuropathy may be a manifestation of Guamanian neurodegenerative disease; (2) the declining prevalence of ALS on Guam is not associated with the development of a subclinical form of motor neuron disease; (3) the substantial overlap of Guamanian ALS with parkinsonism-dementia reported in prior decades is no longer apparent; (4) abnormal central conduction, as assessed by tibial SEP's, is present in some patients with Guamanian parkinsonism-dementia.

Electroneuromyography and somatosensory evoked potentials in HTLV-I associated myelopathy

The objective of the present study was to correlate electroneuromyography (ENMG) and evoked potentials findings with clinical aspects and intrathecal synthesis of HTLV-I antibodies production on HTLV-I myelopathy (HAM). Patients were seropositive for HTLV-I by different assays and seronegative for HIV and VDRL. They had no other causes of myelopathy and peripheral neuropathy. Peripheral neuropathy was established in 34.3% of the cases by ENMG. Peripheral neuropathy was mostly asymmetric (82%), sensory motor (90%), axonal (54.5%) or of a mixed type (45.4%). In 63.6% of these cases related symptoms were observed. ABR was abnormal in one patient and the PRVEP in 28.5%, who were symptom-free. The SEP was abnormal in 85.7% of the cases, half of them presenting clinical complaints. In only 14% of the individuals with clinical manifestations, SEP was normal. In 28% of patients with abnormal SEP the ENMG disclosed a peripheral neuropathy.

Multimodality evoked potentials as a prognostic tool in term asphyxiated newborns

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

Corrélations entre déficits cliniques, potentiels évoqués moteurs et sensitifs, et aspects radiologiques à l'IRM dans la syringomyélie malformative. À propos de 27 cas

Twenty-seven patients (15 males, 12 females, age range: 16-66 years) were admitted for malformative syringomyelia diagnosed on MRI with measures of syrinx extending and transverse diameter. Posterior tibial somatosensory evoked potentials (PT SEP), median (M SEP), trigeminal (V3 SEP), brain stem auditory evoked potentials (BEAP), cortical and cervical motor evoked potentials (MEP) were correlated with clinical and radiological findings. SEP abnormalities were not correlated with the duration of symptoms. PT SEP proved to be more sensitive than M SEP. MEP abnormalities were very frequent (87% of the cases), even without clinical motor deficits. Trigeminal SEP were more sensitive than BEAP which were not related to the presence of associated cranio-vertebral abnormalities. We found no significative relationship between clinical and radiological results. Moreover, there was a positive relationship between electrophysiological and radiological results: abnormal trigeminal SEP were detected in 85% of the patients with high cervical syringomyelia. In all cases, trigeminal SEP and MEP should be done in association with M and PT SEP as both of them detect subclinical evidence of spinal cord dysfunction in syringomyelia.

Somatosensory Evoked Potential Monitoring During Cotrel-Dubousset Instrumentation

Somatosensory evoked potentials produced by electrical stimulation of the posterior tibial nerve were recorded from surface electrodes at the scalp and cervical spine of a patient with scoliosis undergoing posterior spinal fusion with Cotrel-Dubousset instrumentation. During spinal derotation when hypotension and anemia were also present, the cortical and subcortical somatosensory evoked potentials disappeared. During a wake-up test, the patient demonstrated weakness of the left lower extremity, and derotation was stopped. The patient was given pharmacologic hypertensive agents and blood transfusions to increase blood pressure. Forty minutes later, somatosensory evoked potentials returned and a second wake-up test demonstrated normal function in both lower extremities. This report demonstrates the accuracy and usefulness of somatosensory evoked potential monitoring during spinal fusion with Cotrel-Dubousset instrumentation. To the authors knowledge, this is the first report demonstrating a correlation between abnormal SEP responses and intraoperative neurologic deficit during the derotation maneuver with Cotrel-Dubousset instrumentation and corrected by transfusion and restoration of normotension.

A prospective 1 year follow-up study with somatosensory potentials evoked by stimulation of the posterior tibial nerve in patients with supratentorial cerebral infarction

Somatosensory potentials evoked by stimulation of the posterior tibial nerve (tibial nerve SEPs) were studied in 40 patients with supratentorial non-haemorrhagic cerebral infarction and in 25 control subjects. SEPs were recorded twice in 39 patients and thrice in 35 patients. The first examination was carried out 4–19 days after the onset of the symptoms, the second examination 56–100 days after the stroke, and the third examination 348–393 days after the stroke. Increased side-to-side differences in the P57 and N75 peak latencies and absence of the P40 peak were the most frequent abnormal findings. The latency abnormalities were associated with involvement of the subcortical white matter of the rolandic region. The absence of the P40 peak was, in contrast, closely related to the extension of the infarcted area into the cortical gray matter of during the acute stage, 51% of patients had abnormal SEPs in the second examination and 43% of patients in the third examination. A nearly significant decrease was observed in the number of latency abnormalities, but the number of amplitude abnormalities, including absent responses, did not change during the 1 year follow-up period.