Typical EEG Findings Research Articles

Creutzfeldt–Jakob disease

Creutzfeldt-Jakob disease (CJD) is a progressive, degenerative, and fatal disease of the central nervous system. It is caused by abnormal accumulation of prion proteins and is characterized mainly by progressive dementia, myoclonus, and cerebellar, pyramidal, and extrapyramidal findings. Psychiatric symptoms may also accompany CJD and are often the first signs of the disease. The incidence of CJD is approximately 1 in 1 000 000. In certain cases, a diagnosis can be made by demonstrating the accumulation of pathological prion proteins. However, in many cultures brain biopsies or post-mortem evaluations are not welcomed by either the patients or their relatives. In these cases, the importance of additional diagnostic tools increases. Herein, we report on a CJD patient who first consulted a psychiatrist with early psychiatric symptoms. The patient developed neurological symptoms later and was subsequently diagnosed as sporadic CJD based on clinical and laboratory findings rather than brain biopsy. Repeated electroencephalograms (EEG) played a pivotal role in our evaluation of the patient. This case is an interesting presentation of CJD both because of the timing of the symptoms and because of the typical EEG findings that led to the diagnosis.

EEG Findings during Tilt-Table induced Asystole: A Case Report

ABSTRACT.Episodic loss of consciousness can be caused by epileptic seizures, but other etiologies must be considered. We report a patient with dramatic loss of consciousness during tilt-table testing and discuss the typical EEG findings and clinical manifestations during convulsive syncope.

EEG and magnetic resonance imaging abnormalities in patients with acute limbic encephalitis

OBJECTIVE: To describe the characteristics of electroencephalography (EEG) and MRI in patients with acute limbic encephalitis (LE). PATIENTS AND METHODS: We retrospectively reviewed medical records of 57 patients with diagnosis of LE from May 1994 to April 2010 and selected those with available EEG and MRI records. We analyzed EEG characteristics (type of abnormality, location and periodicity), reviewed MRIs and compared both. RESULTS: We included 22 patients, age ranging from 3 months to 71 years. EEG was abnormal in 21 patients (95.5%): Periodic lateralized epileptiform discharges (PLEDs) in 9 patients (40.9%), epileptiform discharges and/or temporal slow waves in 7 (31.8%) and 5 (22.7 %) with only background slowing. MRI showed abnormalities in temporal lobes of 19 patients (86.4%). The presence of PLEDs was strongly associated with hyperintense MRI-FLAIR signal involving hippocampus and temporal lobe cortex. Bilateral periodic lateralized epileptiform discharges (Bi-PLEDs) seen in two patients were related to extensive symmetrical bitemporal hyperintense MRI-FLAIR signal. Three patients with PLEDs had only mild ipsilateral FLAIR-hyperintense abnormalities, while contralateral temporal areas were moderate to severely affected on MRI. In four patients with smaller asymmetric bilateral lesions we observed PLEDs in the most affected side. Diffuse slow waves were observed in three patients with discrete hyperintense signal on MRI. CONCLUSION: PLEDs are a typical EEG finding in LE, but not present in all cases. However EEG may predict the extension of MRI abnormalities: slow, mild and nonspecific EEG abnormalities may be related to discrete MRI lesions, while PLEDs to extensive lesions. Moreover, in bilateral, asymmetrical and widespread lesions PLEDS may be contralateral to the most affected ("burned-out") area on MRI.

Coexistence of epileptic encephalopathy with continuous spike-and-wave during sleep, atypical benign partial epilepsy, and fixation-off sensitivity in two siblings

Epileptic encephalopathy with continuous spike-and-wave during sleep is a rare age-related childhood encephalopathy characterized by neuropsychological and motor impairment, epilepsy, and typical EEG findings. Fixation-off sensitivity denotes forms of epilepsy and/or EEG abnormalities that occur during eye closure. The authors describe a girl with developmental regression, electrical status epilepticus during sleep (documented by video/EEG recording), and intermittent myoclonus. Her younger brother was diagnosed with atypical benign partial epilepsy, and his repeated video/EEG recordings unexpectedly showed fixation-off sensitivity.

The effect of electrophysiological and neuroimaging findings on the prognosis of juvenile myoclonic epilepsy proband

Background: Juvenile myoclonic epilepsy (JME) is a well-defined idiopathic generalized epileptic syndrome, and diagnostic criteria for JME are to have a normal brain imaging and clinical evidence of typical epileptic seizures. The aim of this study is to evaluate electrophysiological and neuroimaging findings of JME and determine their relationship with prognosis.Methods: Thirty-two patients (23 women and nine men) with a mean age of 22 (16–37) years were included in this study. Interictal electroencephalography (EEG), magnetic resonance imaging (MRI) and single photon emission computed tomography (SPECT) were carried out in all patients.Results: Analysis of premedication EEGs revealed primary generalized pattern activity in 75% (n=24) and focal abnormalities in 18·75% (n=6). MRI was abnormal in seven (21·88%) patients (two with arachnoid cyst, two with mild cerebral atrophy, two with ventricular enlargement and one with single gliotic lesion), and SPECT imaging detected hypoperfusion in 15 (47%) patients. Hypoperfusion was mostly found on the parietal lobe.Conclusion: We found that, after medication, only 6·25% of EEGs had primary generalized pattern activity (p<0·0001); nevertheless, the prognosis was good in patients who had typical EEG findings (p=0·106). The prognosis of patients with MRI abnormalities was grave (p=0·023). Twenty percent of the patients who had SPECT abnormalities were seizure free, and 80% of them had been partially controlled (p=0·059). There were no correlations between MRI abnormalities, EEG and SPECT findings.

Combined Transcranial Doppler and EEG Recording in Vasovagal Syncope

Background: In neurally mediated syncope a ‘typical’ EEG pattern during hyperventilation (HV) may be observed. This study aimed to investigate transcranial Doppler (TCD) and EEG variations in response to hyper- and hypocapnia using simultaneous recording. Methods: Syncope patients with a typical EEG pattern during HV (SEEG+, n = 15) and those without abnormalities (SEEG–, n = 16) were compared with healthy controls (n = 20). Simultaneous TCD and EEG recordings were performed at rest (baseline), during 2 apnea tests and during HV. Cerebrovascular vasoreactivity, index for hypocapnia, total vasomotor reserve and time to flow velocity normalization after HV (t-norm) were recorded. Results: With TCD, a reduction in Vasomotor reserve was observed in SEEG+ compared with the other 2 groups (control: 67 ± 8%; SEEG–: 67 ± 10%; SEEG+: 57 ± 8%; p < 0.0001). t-norm was longer in all syncopal patients and in particular in SEEG+ (control: 20.2 ± 3 s; SEEG–: 40 ± 7 s; SEEG+: 123 ± 45s; p < 0.0001). Quantitative EEG showed an increase in slow bands in all subjects during HV, small and nonsignificant in controls and SEEG–, higher and significant in SEEG+, related with flow reduction. Conclusions: Changes in the sympathetic modulation of cerebral vasoconstriction may explain both the pathophysiology of vasovagal syncope and the typical paroxysmal EEG findings.

Creutzfeldt-Jakob disease: Which diffusion-weighted imaging abnormality is associated with periodic EEG complexes?

Clinical diagnosis of CJD remains important due to lack of access to a genetic or histopathological diagnosis. Using current WHO criteria, diagnostic certainty can be increased from "possible" to "probable" CJD if periodic complexes are recorded on EEG. To study the correlation between patterns of MRI-DWI hyperintensity and typical EEG findings among patients with CJD. Demographics, clinical findings, MRI-DWI and EEG findings of CJD patients were retrospectively reviewed. A total of 14 patients ranging in age from 35 to 81 years were identified. All had dementia and cerebellar ataxia. Psychiatric manifestations were seen in 5 patients. Seven patients had both cortical and striatal DWI changes, five had isolated cortical DWI changes and two had isolated striatal DWI changes. All twelve patients with cortical DWI changes also had periodic EEG changes. In ten, periodic EEG was recorded within seven days of the DWI. The two patients with isolated striatal DWI changes did not develop periodic EEG complexes despite serial EEG recordings, 40 and 88 days from their respective DWI scans. Serial EEGs are not useful for patients with isolated striatal DWI hyperintensity but will increase diagnostic certainty from "possible" to probable" CJD for patients with cortical DWI hyperintensity.

Symptomatic Epilepsies Imitating Idiopathic Generalized Epilepsies

The diagnosis of idiopathic generalized epilepsies (IGEs) is not generally difficult if one follows the clinical and electroencephalogram (EEG) definitions of each subsyndrome that constitutes IGEs. In contrast, symptomatic epilepsies develop based on organic brain lesions and are easily diagnosed by the presence of developmental delay, neurologic abnormalities, and a characteristic seizure and EEG pattern. However, in clinical practice, it is sometimes difficult to differentiate IGEs from symptomatic epilepsies, especially when the clinical course from the onset of epilepsy is too short to exhibit typical clinical and EEG findings of either epilepsy type, or when patients with symptomatic epilepsies have atypical features that imitate the clinical characteristics of IGEs. The neurodegenerative or metabolic disorders at times start during the clinical course with epileptic seizures and later show typical neurologic abnormalities. The newly recognized metabolic disorder of glucose transporter type 1 deficiency syndrome (Glut-1 DS) may start with myoclonic seizures at an age of less than 1 year and imitate benign myoclonic epilepsy in infancy early in the clinical course. Progressive myoclonus epilepsies (PMEs) that develop at 1-4 years of age at times imitate epilepsy with myoclonic-astatic seizures with respect to the presence of astatic seizures and an epileptic encephalopathic EEG pattern. In addition, young children with focal cortical dysplasia may also have similar clinical and EEG patterns, although the latter may become localized after treatment. Approximately 15% of patients with juvenile myoclonic epilepsy (JME) are resistant to antiepileptic drugs (AEDs) and may require extensive study to make a differential diagnosis from symptomatic epilepsies. PMEs that develop during adolescence may imitate JME early in the clinical course; however, a detailed history and the differentiation between myoclonic seizures and myoclonus would help to distinguish both conditions. The diagnosis of IGEs is very demanding for patients with atypical features with regard to seizure type, EEG findings, and response to appropriate AEDs.

P02.13: Prenatal diagnosis of Aicardi Syndrome (AS)

AS is characterized by infantile spasms, agenesis of corpus callosum and chorioretinopathy. Other abnormalities including neuronal heterotopia, brain tumors, especially choroids plexus papilloma, optic nerve cystic coloboma, and costovertebral defects including hemivertebrae, scoliosis and absent or malformed ribs were reported. The inheritance is X-linked dominant, probably involving a breakpoint at Xp22, with lethality in the hemizygous male. We present a case of agenesis of corpus callosum, interhemispheric cysts, brain heterotopia, unilateral optic nerve coloboma, microftalmia and chorioretinopathy, in a 28 year old gravida 1, para 0, patient in which the AS was prenatally suspected. A female newborn was delivered by C-section at 38 weeks gestation and the prenatal findings were confirmed. A funduscopic examination revealed microftalmia, leucocoria and chorioretinal lacunae in the left eye and multiple lacunae on the right. On the fourth day of life she presented seizures of myoclonic type and typical EEG findings. Only a few cases have been diagnosed before birth. In this case the association of agenesis of corpus callosum and ocular compromise were the clue to prenatal diagnosis. We emphasize the search of subtle ocular abnormalities each time we have hypogenesis or agenesis of corpus callosum.

Temporo-occipital spikes: a typical EEG finding in Kabuki syndrome

Kabuki syndrome is a rare dysmorphogenic disorder. The central nervous system is often involved, and epilepsy is a common symptom. The diagnosis is clinical, and no typical electroencephalographic findings have thus far been reported. We have documented temporo-occipital spikes in sleep electroencephalogram in all our three Kabuki patients. The location of the spikes was similar in all cases although their occurrence varied from continuous spiking to single spikes. We suggest that temporo-occipital spikes are typical in Kabuki syndrome and discuss the possible cause of this finding.

Combined assessment of obstructive sleep apnea syndrome with dynamic MRI and parallel EEG registration: initial results.

To detect obstructive pharyngeal changes in sleeping patients with obstructive sleep apnea syndrome by dynamic MRI and concurrent EEG monitoring during true apneic episodes. Five volunteers and eight patients with clinically diagnosed obstructive sleep apnea were polysomnographically monitored inside the scanner before, during, and after sleep discontinuation. After sleep interruption, the Mueller maneuver was performed to compare induced pharyngeal collapse with real collapse during sleep. In all patients, on-line EEG registration was achieved in the static magnetic field. Sleep was proved in four of the eight patients who showed typical EEG findings. A complete pharyngeal collapse was shown in two of the four sleeping patients. The other patients predominately showed local epi- and oropharyngeal obstructions in the apneic state. Compared with the apneic episodes, the Mueller maneuver did not reveal the same extent of pharyngeal narrowing, nor a complete collapse. Polysomnographically monitored MRI can directly assess findings induced by the pathophysiology of sleep apnea and shows promise for use in sleep investigation and therapy planning and monitoring.

Creutzfeldt-Jakob disease in health professionals in Slovakia.

Creutzfeldt-Jakob disease (CJD) is the most important human transmissible spongiform encephalopathy (prion disease), recognised in sporadic, genetic but also iatrogenic forms. The identification of 8 health care workers in a group of 114 definitive CJD patients in Slovakia suggested the possibility of professionally acquired CJD and induced the investigation of potential endo- and exogenous risk factors. In CJD-affected health professionals special attention was paid to a detailed occupational history, including a possible professional contact with CJD patient and to the findings characteristic for iatrogenic CJD: early cerebellar symptomatology, long duration of the disease, absence of typical EEG finding and homozygosity of PRNP gene at codon 129. Analysis of epidemiological, clinical and molecular biological data in investigated group of CJD-affected health professionals gave no evidence of an occupational risk for CJD.

Progressive myoclonus epilepsy of Unverricht-Lundborg type.

Progressive myoclonus epilepsy of Unverricht-Lundborg type (EPM1) is characterized by onset at age 6-15 years, stimulus-sensitive myoclonus, tonic-clonic seizures, and typical EEG findings, with marked sensitivity to photic stimulation. Previously the course of the disease was progressive throughout the life, and no biochemical or pathologic marker existed for the diagnosis of EPM1. With modern anticonvulsive therapy, the prognosis has improved significantly, the symptoms are nowadays relatively well controlled, and the disease may not always progress. Moreover, the molecular genetic findings have now made possible an etiologic diagnosis of EPM1. The positional cloning strategy was applied to identify the gene whose defects are responsible for EPM1. The underlying gene encodes cystatin B, a cysteine protease inhibitor. The major mutation worldwide is an unstable expansion of a dodecamer minisatellite repeat unit in the promoter region of the cystatin B gene. In addition, five "minor" mutations have been described. Cystatin B mutations are now known to account for both Mediterranean myoclonus and for "Baltic" myoclonus, described mainly from Finland, thus solving a long-term controversy and proving that these two disorders are one single disease entity. The pathogenetic mechanisms in EPM1 are yet unknown, but in the majority of patients, a reduced level of the cystatin B gene product seems to be the primary mechanism in the pathology. Understanding the molecular pathogenesis of EPM1 may lead to the development of specific therapies for the disease.

Benign epilepsy of childhood with centrotemporal spikes.

Benign epilepsy of childhood with centrotemporal spikes (BECT) is the most common partial epilepsy syndrome in the pediatric age group, with an onset between age 3 and 13 years. The typical presentation is a partial seizure with parasthesias and tonic or clonic activity of the lower face associated with drooling and dysarthria. Seizures commonly occur at night and may become secondarily generalized. They are usually infrequent and may not require antiepileptic drugs but, if treated, they tend to be easily controlled. Children with BECT are neurologically and cognitively normal. The EEG shows characteristic high-voltage sharp waves in the centrotemporal regions, which are activated with drowsiness and sleep. In this typical form, BECT is easily recognized. However, atypical cases are common and the definition of BECT can become blurred. Although further investigations are not required in cases with typical clinical and EEG findings and normal neurologic examinations, neuroimaging studies may be required in atypical cases to rule out other pathology. The long-term medical and psychosocial prognosis of BECT is excellent, with essentially all children entering long-term remission by mid-adolescence.

Evolution of epilepsy and EEG findings in Angelman syndrome.

To evaluate the evolution of epileptic seizures and EEG features in a large group of patients with Angelman syndrome (AS). Thirty-six patients with AS with a proven chromosome 15q11-13 deletion were retrospectively analyzed with regard to their epilepsy and EEG findings by examination of patient files and EEGs. AIJ EEGs were reviewed by one of the authors. A logistic regression model, with a follow-up from 1 to 39 years (mean, 15 years), was used for statistical analysis. Epileptic seizures had occurred in 30 (83%) patients. In 43% of them, the initial symptoms of epilepsy were febrile convulsions in infancy. In childhood, epilepsy could start with almost any type of seizure. Atypical absences and myoclonic seizures prevailed in adulthood. Epileptic seizures were present in 92% of the adult patients. The most typical EEG findings were rhythmic triphasic delta waves of high amplitude with a maximum over the frontal regions, identified in 99 (66%) of 150 EEGs, and continuously or intermittently, in 30 (83%) of 36 patients with AS. In 47% it was present even before a clinical diagnosis of AS was considered. High-amplitude rhythmic 4-6/s slow activity, seen in 44 (29%) of 150 EEGs, was not present after the age of 12 years. In contrast to previous reports suggesting a decreasing frequency of epileptic seizures with age, we found that 92% of the adult patients with AS continued to have epileptic seizures. The most typical EEG finding in AS, in both children and adults, was the presence of frontal triphasic delta waves. In mentally retarded patients, this EEG pattern should point the physician in the direction of AS.

Lennox-Gastaut Syndrome in the Elderly?

The Lennox-Gastaut syndrome (LGS) is an electro-clinical syndrome of early childhood that consists of mental retardation, intractable generalized epilepsy with multiple seizure types, and typical EEG findings. We report a 64-year-old woman who was referred for presurgical evaluation with a diagnosis of intractable temporal lobe epilepsy since the age of 14 years, consisting of staring and unresponsiveness, sudden falls, and generalized convulsions. The average seizure frequency was 1-4 per month. Mental status and neurological examination were normal. There was no known etiology and magnetic resonance imaging (MRI) of the brain was normal. Interictal EEG showed findings characteristic of LGS: generalized slow spike-wave complexes, multifocal sharp waves, generalized polyspikes and paroxysmal fast activity during sleep. Despite the absence of mental retardation and the presence of normal alpha rhythm, the patient fulfills most diagnostic criteria for LGS, with unusually late onset and extremely delayed diagnosis. This case illustrates the controversial nosologic boundaries of the syndrome. Prolonged EEG video monitoring may be of value even in the elderly. The LGS and other varieties of secondary generalized epilepsy should be considered in the syndromic diagnosis of epilepsy in the elderly.

Rett syndrome: EEG presentation

Rett syndrome, a degenerative neurological disorder of girls, has a classical clinical presentation and typical EEG findings. The electroencephalograms (EEGs) of 7 girls whose records have been followed from the onset of symptoms to the age of 5 or more are presented. These findings are tabulated with the Clinical Staging System of Hagberg and Witt-Engerström (1986). The records show a progressive deterioration in background rhythms in waking and sleep. The abnormalities of the background activity may only become evident at 4–5 years of age or during stage 2 — the Rapid Destructive Stage. The marked contrast between waking and sleep background may not occur until stage 3 — the Pseudostationary Stage. In essence EEG changes appear to lag behind clinical symptomatology by 1–3 years. An unexpected, but frequent, abnormality was central spikes seen in 5 of 7 girls. They appeared to be age related and could be evoked by tactile stimulation in 2 patients. We hypothesize that the prominent ‘hand washing’ mannerism may be self-stimulating and related to the appearance of central spike discharges.

Some clinical and EEG aspects of benign juvenile myoclonic epilepsy.

Twelve patients with benign juvenile myoclonic epilepsy (BJME) representing 4% of our population of epileptics (n = 275) are presented. Only two patients (17%) had myoclonic jerks as the only seizure type. Seven (58%) had generalized tonic-clonic seizures (GTCS) and myoclonus. Three patients (25%) had absence seizures (AS), GTCS, and myoclonic jerks. Electroencephalographic evidence of photosensitivity was found in four (33%). Auditory precipitation of seizures was found in one patient. As is the case with other primary generalized epilepsies, the onset of BJME seems to be age specific. In our series the mean age of onset in years was 4.3 for AS, 14.75 for myoclonic jerks, and 16.4 for GTCS. It took an average of 8.5 years from the onset of BJME (range, 2-20 years) and 6.5 years from the onset of GTCS (range, 2 months-6 years) until the condition was properly recognized. Five patients experienced at least one episode of myoclonic status epilepticus. Generalized, paroxysmal, symmetric polyspike and slow wave discharges are the typical EEG finding. These complexes, however, showed considerable interpatient variability. Sleep deprivation proved to be the most valuable activating procedure. Valproic acid monotherapy effectively controlled myoclonic jerks as well as associated GTCS in most patients.

A case of subacute encephalitis

A case of subacute encephalitis with typical EEG findings is reported. The post mortem failed to reveal inclusion bodies or demyelinization.