Clinical Neurophysiology: Clinical EEG
2005; Wiley; Volume: 46; Issue: s8 Linguagem: Inglês
10.1111/j.1528-1167.2005.460801_15.x
ISSN1528-1167
Tópico(s)Neurological and metabolic disorders
ResumoEpilepsiaVolume 46, Issue s8 p. 131-142 Free Access Clinical Neurophysiology: Clinical EEG First published: 19 October 2005 https://doi.org/10.1111/j.1528-1167.2005.460801_15.xAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract 1 Imran I. Ali, 1 Nabeel A. Herial, 1 Noor A. Pirzada, 1 Neeraj Kaplish, and 1 L. John Greenfield ( 1 Neurology, Medical University of Ohio, Toledo, OH ) Rationale: Status epilepticus (SE) from all causes is associated with a 25–30% mortality rate. In patients with hypoxic-ischemic encephalopathy (HIE) and SE, the mortality is even higher. Effect of non-convulsive status epilepticus (NCSE) in this group have not been described previously. We, therefore, wanted to review the EEG features of SE in patients with HIE to correlate them with the clinical findings and also identify patients in which intervention may be associated with a better prognosis. Methods: The EEG database at Medical University of Ohio from 1999–2004 was reviewed. Patients with HIE and fulfilling the EEG criteria for status epilepticus were identified. EEG were reviewed by two Board Certified Electroencephalographers and charts were reviewed for clinical and EEG information. IRB approval was obtained for this study. Results: Twelve patients were identified who fulfilled the criteria for for HIE and NCSE. There were six men and six women. Mean age was 60.5 years (range 38–85). Six patients had isolated cardiac arrest, two had purely respiratory arrest while four had simulatneous cardiorespiratory arrest. Six patients were comatose with no clinical evidence of seizures (50%), three patients (25%) had intermittent myoclonus, while two patients (16%) had focal clonic activity noted initially. One additional patient had generalized tonic clonic seizure that was followed by coma and EEG evidence of NCSE. Irregular bifrontal generalized spike and wave discharges were seen in six patients (50%), generalized periodic epileptiform discharges with evolving pattern were seen in five patients (42%), and focal rhythmic spike and wave activity was seen in one patient (8%). Severe background suppression was noted in all patients. Three patients had intermittent theta activity but the background was unreactive. In nine patients NCSE resolved with treatment but in all twelve patients this did not result in improvement of the background EEG activity. All twelve patients died within 30 days of onset of NCSE. Conclusions: EEG features of non-convulsive status epilepticus are variable but most patients had generalized periodic epileptiform discharges with evolving frontal discharges or rhythmic frontal spike and wave activity. The EEG pattern did not influence outcome or correlate with specific clinical features. In our series non-convulsive status epilepticus in patients with hypoxic ischemic encephalopathy was associated with a 100% mortality. Although status epilepticus resolved in 66% of the patients with aggressive treatment, this did not result in improved outcome. 1 Noel Baker, and 1 Paul C. Van Ness ( 1 Neurolgy, University of Texas Southwestern Medical Center, Dallas, TX ) Rationale: Subclinical Rhythmic Epileptiform Discharge of Adults (SREDA) is a non-ictal electrographic variant most frequently characterised as a 5–7 Hz rhythm of abrupt onset and termination and located maximally in the temporoparietoocipital regions. It differs from an ictal pattern in a lack of evolution in frequency, distribution and morphology, and in the subjects' lack of clinical change during the duration of the discharge.(1) SREDA has most often been described in adults in the 4th to the 9th decades, but Najarajan et al have described this pattern in 2 young girls.(2,3) We report its occurrence in a young man whose SREDA had characteristics described as rare in adults. Methods: In the pediatric division of our institution, approximately 2200–2500 routine EEGs and 150–200 prolonged video-EEG studies are performed each year. Since 2001, only one case of SREDA in a pediatric patient was seen in our institution. Results: Case Report: The patient initially presented at the age of 14 for staring spells. His neurologic examination and IQ were normal. An intial routine and video EEG were interpreted as showing non-convulsive status, despite his ability to interact during the discharges. He was placed on valproate with no clinical change. A second video EEG 3 years later showed bursts of 5–6 Hz discharges occaisionally slowing to 1–2 Hz which were consistently maximal in the frontal regions and at the vertex, bilaterally synchronous in onset, and persisting in light sleep. The bursts lasted up to 5 minutes in duration and ended abruptly with re-emergence a normal background, and comprised >50% of the record during the 3 days of monitoring. The SREDA persisted unchanged during activation procedures, eye opening and closing, and repetition of syllables such as “lilt.” During the bursts, he repeatedly demonstrated his ability to follow commands, answer questions, play video games, and complete neuropsychologic testing. Conclusions: SREDA is rare EEG pattern occurring in approximately 1/2500 adult recordings and documented in patients with such non-epileptiform complaints as headaches, dizziness, and depression, as well as seizures. Atypical SREDA variants charcterised as frontally predominant, or occurring as delta frequencies, or having a waxing and waning pattern have also been described, comparable to what we saw in our patient. (2) While our experience at our institution confirms that of Nagarajan et all that SREDA is not seen exclusively in adults, it also suggests that SREDA is more rare in pediatric patients. 1 Westmoreland B. and Klass D. A Distinctive Rhythmic EEG Discharge of Adults. Electroencephalography and Clinical Neurophysiology, 1981, 51:186–191. 2 Westmoreland B. and Klass D. Unusual variants of subclinical rhythmic electrographic discharge of adults (SREDA). Electroencephalography and Clinical Neurophysiology, 1991, 102:1–4. 3 Nagarajan L. et al Subclinical Rhythmic EEG Discharge of Adults: SREDA in Two Children. Pediatric Neurology, 2001; 24:313–316. 1 Ramon E. Bautista, 2 Steven Godwin, and 2 David Caro ( 1 Department of Neurology, University of Florida Health Sciences Center/Jacksonville, Jacksonville, FL ; and 2 Department of Emergency Medicine, University of Florida Health Sciences Center/Jacksonville, Jacksonville, FL ) Rationale: Patients frequently present to the emergency room (ER) with mental status changes but without any immediately apparent cause. The EEG is underutilized in this population, partly due to the time and preparation required to perform it, possibly causing a delay in diagnosis. In this study, we determined if an abbreviated EEG (AEEG) performed immediately upon patient arrival to the ER could provide useful information. We specifically wanted to know if AEEGs can be useful in diagnosing non-convulsive status epilepticus (NCSE). Methods: We performed a 5-minute AEEG using a preformed electrode placement system on 25 consecutive patients who presented to the ER with mental status changes but without any immediately apparent cause as determined by ER physicians. The AEEGs were performed almost immediately after the patient arrived in the ER without the benefit of a neurologic consultation. The AEEGs were only reviewed after patient discharge and did not impact patient care. We also conducted a retrospective chart review of all enrolled patients after discharge to determine the discharge diagnosis. We then performed a Fisher exact test to determine if the cause of mental status changes could be distinguished by AEEG findings. Results: Of 25 patients entered into the study, two had a discharge diagnosis of new onset NCSE. These patients had AEEG findings consistent with electrographic seizure activity. Seven patients were later diagnosed to have a metabolic/infectious encephalopathy. The AEEGs in four of these patients showed diffuse slowing and one had interictal epileptiform activity. Eight patients were seen due to post-ictal confusion and seven of them had AEEGs that showed diffuse slowing. Two patient were diagnosed with syncope and both had normal AEEGs. One patient had a left MCA-CVA and the AEEG showed diffuse slowing that was accentuated over the left hemisphere. One patient was diagnosed with dementia and had a normal AEEG. The diagnoses in four patients were uncertain even at the time of discharge. Three of these patients had a normal AEEG while one AEEG was uninterpretable due to movement artifact. Aside from those who were diagnosed to have NCSE, no other patient had an AEEG showing electrographic seizure activity. Using Fisher's exact test, mental status changes due to NCSE could be distinguished by the presence of electrographic seizure activity on AEEG. Conclusions: Our study suggests that even an abbreviated EEG performed early during the ER visit can diagnose NCSE in patients who present with mental status changes of unknown cause. Future studies with larger sample sizes would help definitively establish the utility of this technique. (Supported by University of Florida Health Sciences Center/Jacksonville Dean's Fund Research Awards for Faculty.) 1 Scott Bearden, 1,2 Basim Uthman, and 2 Stephan Eisenschenk ( 1 Neurology, North Florida/South Georgia Veterans Health System, Gainesville, FL ; and 2 Neurology, University of Florida, Gainesville, FL ) Rationale: Nonconvulsive status epilepticus (NCSE) is most often defined as an epileptic state, without convulsive motor activity, lasting at least 30 minutes with associated ictal EEG activity. A clinically evident, sustained change from baseline behavior or mental status should also occur unless the patient is comatose or in simple partial NCSE. Diagnostic challenges are most evident in NCSE patients presenting with stupor or coma since no or only little behavioral changes are clearly apparent. Identifying EEG patterns that are most probably ictal representations of NCSE could be most valuable in early diagnosis and treatment of NCSE. Delay to diagnosis of adult NCSE may increase morbidity and mortality. Methods: A thorough review of the literature from 1972 to 2004 identified 72 publications involving NCSE in adults. Clinical and EEG presentations of reported cases were analyzed and supplemented with examples from our clinical practice. Results: We devised a classification scheme summarizing clinical presentations and ictal EEG patterns of NCSE. Five clinical categories combined with common ictal EEG signatures were identified and referenced in five charts integrating the type of NCSE, common patient symptomatology, ictal EEG, interictal EEG, and prognostic information. Two flow charts (combining clinical presentation and EEG) were developed to aid in classification and provide prognostic information for most adult patients in NCSE whose mental state ranges from mild confusion to stupor and for patients who are comatose. The use of benzodiazepines as a diagnostic aide during EEG was scrutinized. Conclusions: Classification of prolonged ictal confusion, stupor and coma utilizing clinical and EEG presentations into a simple logical framework is possible and may contribute to early diagnosis and timely treatment of NCSE. High awareness of NCSE as a clinical entity presenting as change in mental status is critical for early diagnosis and intervention. 1 Rachel Berman, 2 Michiro Negishi, 2 R. Todd Constable, 3,4 Edward J. Novotny, 3 Susan Levy, and 4,5 Hal Blumenfeld ( 1 Interdepartmental Neuroscience Program, Yale University, New Haven, CT ; 2 Diagnostic Radiology, Yale University, New Haven, CT ; 3 Pediatrics, Yale University, New Haven, CT ; 4 Neurology, Yale University, New Haven, CT ; and 5 Neurobiology, Yale University, New Haven, CT ) Rationale: Absence seizures occur most commonly in children. They involve brief episodes of staring and non-responsiveness. Electroencephalogram (EEG) recordings of typical childhood absence epilepsy (CAE) show bilateral 3–4 Hz spike-wave discharges. True CAE rarely persists to adulthood. Prior published reports of functional magnetic resonance imaging (fMRI) in adult patients describe variable bilateral frontoparietal fMRI increases, decreases, and thalamic increases during generalized spike-wave, with most studies performed at 1.5T. The goal of the present study is to extend these investigations to typical absence seizures in the pediatric population, which may differ from adult patients, using combined EEG and fMRI at 3T. Methods: Pediatric patients with typical absence seizures, and no other seizure types, were tested. After application of a 19 channel EEG cap connected to an EEG recorder (Neuroscan NuAmps), fMRI was performed using a 3T MR system (Siemens Trio), with continuous EPI BOLD sequence. Multiple 10 minute imaging runs were repeated up to 6 times. To increase the chance of obtaining absence seizures, patients were asked to hold medications for up to 48 hours, and were sleep deprived the night before scanning. EEG artifact was removed by post-processing using temporal PCA-based gradient noise removal. fMRI data during seizure and baseline intervals were analyzed in a general linear model using SPM2. Results: During typical childhood absence seizures, we found significant blood oxygenation level dependent (BOLD) signal increases in bilateral thalamus. Moderate increases were found in the cingulate, lateral frontal, and parietal cortex. Decreased BOLD signal was observed in the retrosplenial cortex, and to a lesser degree in the bilateral frontoparietal cortex. Conclusions: Despite increased challenges of performing fMRI in pediatric patients, high quality data can be obtained in this population. As in adult patients, increases and decreases are seen in frontoparietal and thalamic networks. Further study is needed to determine whether variable involvement of different specific regions of cortex and thalamus during absence seizures is related to variable effects on cognition seen during these seizures. (Supported by Betsy and Jonathan Blattmachr Fund.) 1 Milan P. Borkovic, 1 Nebojsa J. Jovic, and 1 Jasna Jancic ( 1 Clinical for Neurology and Psychiatry for Children and Youth, Medical School, University of Belgrade, Belgrade, Serbia, Yugoslavia; Clinical for Neurology and Psychiatry for Children and Youth, Medical School, University of Belgrade, Belgrade, Serbia, Yugoslavia; and Clinical for Neurology and Psychiatry for Children and Youth, Medical School, University of Belgrade, Belgrade, Serbia, Yugoslavia ) Rationale: Juvenile myoclonic epilepsy (JME) is an idiopathic generalized epileptic syndrome. It is often considered as benign because of its non-lesional nature and favourable clinical long-term prognosis. The characteristic EEG pattern is presented with bilateral symmetric polyspike-wave complexes with anterior accentuation. Focal EEG abnormalities are not exclusive in patients with an unequivocal diagnosis of JME. Methods: A Group of 39 patients of both sexes (17 male, 22 female), aged from 12 to 26 years (mean 17.8 years) with JME were studied for focal EEG abnormalities recorded during the clinical follow-up. Mean seizure onset was 13.5 years. Diagnosis was made according to the history and EEG records. Antiepileptic treatment was started with valproate. Results: Initial clinical and EEG assesment was carried-out after the generalized tonic-clonic seizure (mainly induced by sleep-deprivation), in 51% of JME patients. Absences in 21% and myoclonic jerks in 28% of patients were observed as initial epileptic events and reffered for EEG examinations. Complete, stable, long-term seizure control was achieved with valproate use in 87% of patients. In remaining 13% no favorable therapeutic response of AEDs was noted, mainly due to the irregular lifestyle. Repeated EEGs during sleep and when awake showed the interictal polyspike-wave pattern or fast/classical spike-wave discharges. Generalized EEG patterns were prevalent as expected: polyspike-waves or spike-wave discharges non-related to photic stimulation were noted in 66.7% and paroxysmal abnormalities to photic stimulation in 35.9%. Non-specific abnormalities were shown in 10.3%, while, bilateral anterior spikes and sharp waves were recorded in 23.1% of JME adolescents. Localization-related EEG abnormalities (focal slow waves shifting between the hemispheres, spikes, sharp waves and focal onset or asymmetrical generalized discharges) were noted in 23,1% of our JME patients. Conclusions: In more than one fourth of our JME patients, EEG showed focal abnormalities in addition to the generalized EEG patterns. These features should not be mislead to the erroneous interperetation of EEG characteristic for localization-related epilepsy. 1 Luiz E. Betting, 1 Susana B. Mory, 2 Iscia Lopes-Cendes, 1 Li M. Li, 1 Marilisa M. Guerreiro, 1 Carlos A.M. Guerreiro, and 1 Fernando Cendes ( 1 Department of Neurology, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil ; and 2 Department of Medical Genetics, University of Campinas (UNICAMP), Campinas, São Paulo, Brazil ) Rationale: The objectives of this study were to investigate the EEG profile in a group of patients with clinical diagnosis of idiopathic generalized epilepsy (IGE) followed in a tertiary Hospital and to evaluate the contribution of the records for diagnosis and management of these patients. Methods: We retrospectively studied clinical and EEG features of 180 consecutive patients with IGE. Eighty patients were diagnosed with juvenile myoclonic epilepsy (JME), 35 had absence epilepsy (AE), 13 had generalized tonic-clonic seizures on awakening (GTCS-A), 28 had generalized tonic-clonic seizures only (TCS) and 24 had adult onset idiopathic generalized epilepsy (AIGE). The EEGs were classified in typical (synchronous generalized spike or polyspike and wave discharges with normal background), atypical (with clear focalities or asymmetries) and normal. Results: A total of 493 EEG exams were analyzed. The first EEG was normal in 45% of the 180 patients and only 33% had typical abnormalities. AE had a higher proportion of typical exams and needed less sequential exams to register a typical abnormality compared to the other groups. By contrast, the serial EEG profile of TCS and AIGE showed a higher proportion of normal and atypical EEG findings. Conclusions: These findings support previous recommendations that IGE patients should be treated with appropriate therapy based on clinical history. Waiting for a typical abnormal EEG pattern can generate an unacceptable delay in the correct diagnosis and treatment of these patients. In patients with long term epilepsy the diagnosis may be difficult. Furthermore, serial EEGs can help to elucidate the syndromic diagnosis, especially in patients with TCS and AIGE. (Supported by CAPES, FAPESP.) 1 Farzana Darbari, and 1 Sigmund Jenssen ( 1 Neurology, Drexel Medical College, Philadelphia, PA ) Rationale: Sleep has been shown to influence multiple physiological processes i.e. control of blood pressure, glycemia and protein synthesis, and deprivation of sleep could theoretically lead to sickness. Patients who are admitted to a hospital suffer disturbance of sleep due to external, medical and psychological factors. Disturbed sleep leads to decreased sleep latency. We hypothesized that in-patients have decreased sleep latency as compared to out-patients and that sleep latency decreases with length of stay. Methods: Otherwise completely normal EEG recordings were reviewed prospectively for sleep onset, which we defined as at 30 seconds of stage two of sleep or briefer if stage two of sleep was seen more than once. Patients with known sleep disorders, deliberately sleep deprived recordings and recordings with focal or generalized abnormalities were excluded. We noted medications, length of stay and if recording had been done in AM or in PM. Comparisons were done using the Mann-Whitney test and Pearson's for correlation. Results: Thirty out-patient and 24 in-patient EEGs were reviewed. Mean sleep latency for out-patients was 16 minutes and 54 seconds (SD 11 minutes and 17 seconds) and for in-patients 11 minutes and 27 seconds (SD 8 minutes and 35 seconds). (P = 0.0314). Length of hospital stay and sleep latency did not correlate. There was no statistical difference in age, number of patients on sleep enhancing medications or time of day of EEG between the two groups. Conclusions: In-patients have decreased sleep latency as compared to out-patients. This could be related to disturbed sleep. To see if this is a risk factor for poor recovery needs further investigation. 1 Anita Datta, and 1 David B. Sinclair ( 1 Comprehensive Epilepsy Program, University of Alberta, Edmonton, AB, Canada ) Rationale: The objective of the study was to compare the clinical course and outcome of children with typical and atypical features of Benign Epilepsy of Childhood with Rolandic Spikes (BECRS). Methods: A retrospective case series design was used in the setting of a tertiary care pediatric hospital. One hundred and twenty six children with BECRS were selected for the study. The patients were divided into two groups based on their clinical presentation. Group A consisted of children with typical features of BECRS. Group B consisted of those with atypical features. Atypical features included age of onset, abnormal neurological exam, developmental delay, and presence of other types of seizures. Patients' charts were reviewed for demographic data, family history, comorbid conditions, atypical clinical features, anticonvulsant drugs, and outcome data. Results: Atypical features were seen in 47% of patients. Comorbid disorders such as Attention Deficit Hyperactivity Disorder and behavioral problems, although seen in both groups, were slightly more frequent in the atypical group. Sixty-seven percent of children had a family history of migraine and 54% were migraine sufferers. Overall, there was no difference between time to become seizure free between the groups: 62% of the typical group was controlled on medication by two years while 71% of the atypical group was seizure free. Thirty-five percent of the typical BECRS group were incompletely controlled on medication, while 65% of the atypical group required the addition of a second anti-epileptic drug. Resolution of the epilepsy occurred at about the same age in both groups with similar long term outcomes. Conclusions: Atypical features in BECRS are common. Comorbid disorders are seen in both groups. Personal or family history of migraine appears to be associated with the disorder. Overall, the long term outcome is similar in both groups, although the atypical patients may be initially more difficult-to-control. Resolution of the epilepsy and a good long term outcome was not affected by the presence of atypical clinical features. 1 Ronald G. Davis, and 1 Carl R. Barr ( 1 Pediatric Neurology, Pediatric Neurology, PA, Orlando, FL; and Pediatric Neurology, Pediatric Neurology, PA, Orlando, FL ) Rationale: We report on a large series (>25) of pediatric patients who presented to our neurology practice with various neurologic referable complaints, excluding clinical seizure activity, who were discovered to have EEG abnormalities. Patient ages varied from 3–18years. Symptoms included headache with vertigo, vertigo, visual field alterations including Alice-in -Wonderland changes and atypical speech/language dyspraxia. Prior to presentation, there had been no history of seizure or seizure like activity noted in any of the patients by history and record review. Methods: Routine surface EEG was completed on these patients as part of the workup. Findings included focal sharp wave discharges, focal spike and wave discharges, rhythmic slowing and generalized bursts of spike and polyspike and wave discharges of the non-absence type. A significant percentage also activated with sleep. Neuroimaging was normal in all cases. Therapeutic intervention varied and included the use of antiepileptic medications. Results: A positive response to symptoms (>50% improvement in symptoms) was noted in >50% of patients. Of the initial nonresponders, a second antiepileptic medication was tried. Of those who did not respond to 2 medication trials, discontinuation of medication was recommended. No significant adverse events were reported for any patients who were treated. Conclusions: In conclusion, EEG abnormalities can be seen in pediatric patients with atypical neurologic complaints without clinical seizures.How these electrographic abnormalities contribute to symptoms is unclear. Additionally, guidelines for medication intervention will need to be established, though further investigation will be required. Given these finding and significantly positive clinical response in this limited number of patients, EEG should be considered frequently in the diagnostic evaluation of similar pediatric patients. 1 Eliane Kobayashi, 1 Andrew P. Bagshaw, 1 Jean Gotman, and 1 François Dubeau ( 1 EEG Department, Montreal Neurological Institute and Hospital, McGill University, Montreal, Canada ) Rationale: Cerebral cavernous angiomas (CCAs) are frequently associated with focal intractable epilepsy, and their epileptogenicity is usually attributed to the rim of hemosiderin deposits. Co-recording of EEG and fMRI is a new method to investigate the effects of epileptic discharges in the focus and at distance. Methods: We used EEG-fMRI to identify BOLD responses to interictal spikes in patients with CCAs. Spikes were marked according to spatial distribution, with each spike type determining one EEG-fMRI study. Combined maps of t-statistics were created to assess positive (activation) and negative (deactivation) changes in BOLD signal related to the spikes. Responses were analysed in the lesional and perilesional area, and at distance. The raw fMRI signal in the lesion and its boundaries was evaluated for signal loss due to the susceptibility artefact associated with the lesion and the hemosiderin. Results: Eight patients, three with multiple CCAs, were scanned, all with temporal lobe epilepsy and spikes. One patient had bilateral spikes, analyzed separately, and three studies with less than two spikes were excluded. Therefore, six studies were analyzed, all showing BOLD responses: four had only activation, one had only deactivation and one had both responses. No response was found in the lesion itself or immediate periphery, and the raw fMRI signal showed loss in lesional and perilesional areas in all patients. Responses involved the perilesional area in 2/6 studies, both concordant with the spike topography, one as activation and the other one as deactivation. In all patients, areas of BOLD responses were id
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