Basilar migraine, seizures, and severe epileptiform EEG abnormalities

Four adolescents had basilar migraine, infrequent cerebral seizures, and severe EEG abnormalities. The clinical course was benign, with normal personality, mentation, and neurologic examination. Almost continuous EEG abnormalities, consisting of rhythmic temporo-occipital sharp and slow wave discharges, or generalized spike and wave complexes, were seen in serial recordings. The rare seizures, either focal or generalized, usually followed a migrainous aura and seemed to be readily controlled with anticonvulsant medication. The complex relationship between classical migraine and epilepsy is illustrated by this syndrome; recognition of its relatively benign course may prevent unnecessary investigation and undue alarm.     

Stretch syncope or epileptic seizure? A pathologic hypothesis for self-induced stretch syncope

We report on a 7-year-old female who presented paroxysmal episodes of loss of consciousness with clonic movements. The electroencephalogram (EEG) evidenced diffuse slow wave activations, with no symptoms. Epilepsy was suspected but antiepileptic drugs were ineffective. Video-EEG monitoring revealed that the syncope was triggered by stretching with a tachycardia that started during the stretch maneuver and diffuse slow waves on the EEG 2 s before the symptoms. Stretch syncope can result in striking manifestations with subcortically driven clonic movements that can be mistaken for signs of epilepsy. Stretching might lead to transient hypoxia of the brainstem; in turn, this might activate the thalamocortical loop and thus generate cardiovascular changes, EEG slow waves, and physical manifestations.     

Changes of electroencephalographic findings in a case of migraine with various neurological symptoms

We report here an 1-year-old boy who was diagnosed as sporadic hemiplegic migraine demonstrated transient changes in electroencephalographic (EEG) background activity accompanied with migraine attacks. The attacks were associated with various neurological complications such as impairment of consciousness and hemiplegia and so on, which coincided with the changes of EEG findings. When his first headache developed with fever and impairment of consciousness, diffuse slow waves (1-2 Hz, 250-300 microV) appeared transiently. The slow wave gradually improved thereafter, and disappeared on the 24th day. On the 25th day, when he had the second attack with left hemiplegia and impairment of consciousness and sensation, slow waves, (2-3 Hz, 250-300 microV) appeared on right side of the brain. Constriction of the right middle cerebral artery was found on MR angiography at that time. The EEG change had improved to normal background activity 3 days after the episode. This unique case demonstrated that transient EEG changes seem to be correlated with the existence of unconsciousness and the laterality of the ischemic insult. We may assume that the changes of electroencephalographic findings may represent the cortical dysfunction caused by vascular constriction.     

EEG-mediated diagnosis of an unusual presentation of SSPE.

OBJECTIVE: To highlight the role of EEG in the diagnosis of SSPE. METHODS: EEG was performed in an 18 month old girl who had a 1 week history of repeated episodes of sudden flexion of the head and trunk and frequent falls. RESULTS: EEG abnormalities consisted of stereotyped, generalized and synchronous high amplitude periodic complexes. These abnormalities correlated with brief episodes of axial and upper limb atonia on electromyogram examination. They persisted during sleep although abnormal movements disappeared. Biological results and cerebral MRI confirmed the diagnosis of subacute sclerosing panencephalitis. CONCLUSIONS: This case is exceptional because of the age of the patient, the clinical presentation and the mode of contamination and it highlights the role of EEG in this diagnosis.     

An audit of ambulatory cassette EEG monitoring in children

This audit evaluated the role and usefulness of ambulatory cassette EEG recordings without simultaneous video monitoring in children with paroxysmal episodes including epilepsy. Fifty-four children underwent ambulatory EEG recordings for 48 hours over a 12 month period. Only 31 of the 54 children experienced one of their typical clinical episodes during their recordings. Fifteen of these 31 patients were considered to have epilepsy, only three of whom had a clinical episode at the time of their recording and in all three the EEG demonstrated abnormal (generalized spike and slow wave or focal, rhythmic slow wave) activity. All 10 patients who were considered to have non-epileptic episodes showed no electrical change during their EEG recordings. The results of the ambulatory cassette EEG recordings were considered to have been helpful and to have contributed to the management of only 17 (31%) of the 54 patients in this audit. Stricter clinical criteria for undertaking ambulatory recordings and improved technology are likely to increase the role and usefulness of this procedure.     

Rhythmic fast activity on EEG in a patient with Mollaret's meningitis

Mollaret's meningitis is a rare disease of unknown etiology, characterized by repeated aseptic meningitis with transient neurological symptoms and quick recovery. The patient, a 16-year-old boy, had episodes of acute encephalitis followed by complete recovery every year from the age of 13 to 16 years. The symptoms at onset were loss of consciousness, a generalized tonic clonic seizure and pyramidal signs. He was first admitted to our hospital at the age of 15 years. EEG in the early stage showed diffuse low-voltage rhythmic fast actvity. He recovered consciousness after a week. At the age of 16 years, he was admitted again because of high fever (39 degrees C). Soon after admission, he had generalized tonic-clonic seizure and was accompanied by alternating deep coma and delirium. Cerebrospinal fluid examination during early stage revealed mild leukocytic pleocytosis, elevation of protein and a high level of IL-6. although brain CT and MRI showed no abnormal findings. EEG showed intermittent, diffuse, middle-voltage, rhythmic fast activity. After 5 days, the neurological symptoms completely disappeared with EEG normalization. To our knowledge, this is the first report of rhythmic fast activity on EEG in Mollaret's meningitis. The clinical pictures of this case suggest a transient functional disorder of brainstem or cerebrum may occur in this condition.     

Paroxysmal EEG pattern in a child with N-methyl-D-aspartate receptor antibody encephalitis

A previously healthy 8-year-old male presented with cognitive regression, sleep disturbance, hallucinations, and severe attacks of agitation and oligoclonal bands in the cerebrospinal fluid. N-methyl-d-aspartate receptor (NMDAR) antibodies in serum and cerebrospinal fluid were detected 2 months after onset of symptoms. Bursts of agitation were initially considered to be epileptic leading to the administration of a high dose of benzodiazepines. Video-electroencephalography (EEG) failed to disclose any correlation between the episodes of agitation and paroxysmal rhythmic slow activity on EEG persisting throughout and after attacks of agitation. Clinical improvement and EEG normalization followed an initial plasma exchange performed 3 months after onset of disease. This particular paroxysmal EEG pattern in NMDAR antibody encephalitis suggests that it may result from the combination of reduced NMDAR function and major γ-aminobutyric acid (GABA)-ergic activation.     

Fetal EEG during vacuum extraction delivery with a special plastic ventouse

A vacuum extractor cup made of plastic with built-in percutaneous silver electrodes for fetal EEG and ECG registration is described. In an experimental set up the mechanical properties of the cup were tested. The cup electrodes were tested on a 1-month-old infant and a satisfactory recording was obtained. During delivery a technically acceptable fetal EEG was recorded between but not during tractions. Comparison of the EEG before and after two pulls showed a generalized reduction of amplitude and a decrease of rhythmic slow wave activity. The results indicate that a plastic cup with EEG electrodes might be a useful tool in studying fetal cerebral functions during delivery by vacuum extraction.     

Lennox-Gastaut syndrome (childhood epileptic encephalopathy).

Lennox-Gastaut syndrome (LGS) is a childhood epileptic encephalopathy characterized by an electroclinical triad of generalized slow spike wave (SSW) activity in the EEG, multiple types of epileptic seizures, and slow mental development. It is usually subdivided into symptomatic and cryptogenic types, the latter accounting for at least one fourth of all patients. Symptomatic cases are due to diverse cerebral conditions, which are usually bilateral, diffuse, or multifocal, involving cerebral gray matter. Twenty percent of all patients with LGS have prior infantile spasms with hypsarrythmia. The characteristic interictal EEG pattern of LGS is 1.5 to 2.5 Hz SSW activity, which is bilaterally synchronous, dominant over the frontocentral regions, and usually symmetric. There are varying degrees of slowing of the background. Sleep discloses paroxysms of generalized fast (10 to 25 Hz) rhythmic activity.     

A case of myoclonic astatic epilepsy with autoantibody for glutamate receptor epsilon 2

A 3-year-old boy was admitted to our hospital with repetitive drop attacks and generalized tonic-clonic seizures. Brain MRI, SPECT and blood laboratory tests did not show any abnormalities, while antibody to glutamate receptor epsilon 2 (GluR epsilon 2) in spinal fluid was positive. Interictal EEG showed generalized 6 to approximately 7 Hz slow, wave and ictal EEG showed 1 to approximately 2 Hz high amplitude generalized spike and slow wave burst. We made a diagnosis as myoclonic astatic epilepsy (MAE). However, his seizures were refractory to almost all antiepileptic drugs, steroid pulse therapy and gamma-globulin therapy. Eight months after the first attack, administration of ACTH therapy was effective. Seizures disappeared and EEG findings improved. To our knowledge, there have been no previous reports of MAE in which autoantibody to GluR epsilon 2 was positive. It is suggested that autoimmunity in this case was associated with the pathogenesis of MAE.     

An assessment of 24-hour ambulatory EEG/ECG monitoring in a neurology clinic.

The relative merits of 24-hour ambulatory EEG/ECG monitoring and routine EEG recording have been compared in a group of 62 patients attending a neurological clinic because of episodes of loss of consciousness. Overall, ambulatory EEG abnormalities were detected in 21 cases (34%) compared with 16 cases (26%) for routine EEG. Ambulatory EEG mainly improved the detection of generalised paroxysmal activity, but in some cases lateralised abnormalities were detected which were not present on the routine record. Patients who reported clinical attacks once a week or more frequently showed an improved yield of diagnostic abnormalities on ambulatory EEG, but the technique did not prove superior to routine EEG if attacks were less frequent. The indications for, and limitations of, ambulatory EEG monitoring are discussed.     

Occurrence of nonconvulsive seizures,periodic epileptiform discharges,and intermittent rhythmic delta activity in rat focal ischemia

A significant proportion of neurologic patients suffer electroencephalographic (EEG) seizures in the acute phase following traumatic or ischemic brain injury, including many without overt behavioral manifestations. Although such nonconvulsive seizures may exacerbate neuropathological processes, they have received limited attention clinically and experimentally. Here we characterize seizure episodes following focal cerebral ischemia in the rat as a model for brain injury-induced seizures. Cortical EEG activity was recorded continuously from both hemispheres up to 72 h following middle cerebral artery occlusion (MCAo). Seizure discharges appeared in EEG recordings within 1 h of MCAo in 13/16 (81%) animals and consisted predominantly of generalized 1-3 Hz rhythmic spiking. During seizures animals engaged in quiet awake or normal motor behaviors, but exhibited no motor convulsant activity. Animals had a mean of 10.6 seizure episodes within 2 h, with a mean duration of 60 s per episode. On average, seizures ceased at 1 h 59 min post-MCAo in permanently occluded animals and did not occur following reperfusion at 2 h in transiently occluded animals. In addition to seizures, periodic lateralized epileptiform discharges (PLEDs) appeared over penumbral regions in the injured hemisphere while intermittent rhythmic delta activity (IRDA) recurred in the contralateral hemisphere with frontoparietal dominance. PLEDs and IRDA persisted up to 72 h in permanent MCAo animals, and early onset of the former was predictive of prolonged seizure activity. The presentation of these EEG waveforms, each with characteristic features replicating those in clinical neurologic populations, validates rat MCAo for study of acutely induced brain seizures and other neurophysiological aspects of brain injury.     

CDKL5 gene-related epileptic encephalopathy: electroclinical findings in the first year of life

Aim Cyclin‐dependent kinase‐like 5 (CDKL5) gene abnormalities cause an early‐onset epileptic encephalopathy. We performed video‐electroencephalography (video‐EEG) monitoring early in the course of CDKL5‐related epileptic encephalopathy in order to examine the early electroclinical characteristics of the condition. Method We used video‐EEG to monitor six infants (five females, one male) with CDKL5‐related epileptic encephalopathy (five mutations; one deletion), at ages 45 days to 12 months and followed them up to the ages of 14 months to 5 years (mean age 23mo). We focused our analysis on the first year of life. The results were evaluated against those of a comparison group of nine infants (aged below 1y) with epileptic encephalography who had tested negative for CDKL5 mutations and deletions. Results One infant exhibited normal background activity, three exhibited moderate slowing, and two exhibited a suppression burst pattern. Two participants had epileptic spasms and four had a stereotyped complex seizure pattern, which we defined as a ‘prolonged’ generalized tonic–clonic event consisting of a tonic–tonic/vibratory contraction, followed by a clonic phase with series of spasms, gradually translating into repetitive distal myoclonic jerks. Seizure duration ranged from 2 to 4 minutes. The EEG correlate of each clinical phase included an initial electrodecremental event (tonic vibratory phase), irregular series of sharp waves and spike slow waves (clonic phase with series of spasms), and bilateral rhythmic sharp waves (time locked with myoclonus). Interpretation Infants with CDKL5‐related early epileptic encephalopathy can present in the first year of life with an unusual electroclinical pattern of ‘prolonged’ generalized tonic–clonic seizures.     

Ring chromosome 20 with nonconvulsive status epilepticus: electroclinical correlation of a rare epileptic syndrome.

The electroclinical features of two Thai women with ring chromosome 20 and nonconvulsive status epilepticus (NCSE) were studied. Both have also had generalized tonic-clonic seizures and complex partial seizures of varying frequencies since adolescence. Their intellectual functions were normal. Twenty-four-hour video/EEG telemetry recorded during the NCSE showed fluctuating consciousness between overt unresponsiveness and normal awareness. The EEG consisted of long-lasting generalized rhythmic 3-5 Hz sharp or slow waves with a few spikes, lasting several days. Despite the continuous discharges, the patients had relatively subtle clinical episodes of seizures, during which they were sometimes responsive to verbal stimuli. Intravenous antiepileptic drugs (AED) had little effect on the rhythmic EEG. No lesion in their MRIs contributed to NCSE. Ring chromosome 20 was found in 20% of female karyotype in both patients [46,XX,r(20) (p13 q13)/46,XX] but were negative in four healthy siblings. Oral AEDs decreased more than 75% of the overt CPS episodes in both patients at 22 and 26 months of follow-up but had no effect on the natural history of electrical NCSE. The patients' daily activities were minimally affected by the ongoing electrical discharges. These are the first two cases reported of ring chromosome 20 with NCSE in Thailand. Our patients present a rather benign and pharmacologically responsive course probably because of the low percentage of r(20) mosaicism. The electroclinical correlations in our cases raise the possibility that the mechanism of continuous rhythmic waves in this syndrome may be unrelated to epilepsy. Assessing the severity of this syndrome using both clinical seizures and EEG is crucial.     

Differentiation of Epileptic from Nonepileptic Head Drops in Children

To study the differences between epileptic and nonepileptic head drops, 351 episodes in 24 children were analyzed by EEG-videotelemetry monitoring. Drops were classified as either epileptic or nonepileptic depending on the presence or absence of concomitant ictal EEG discharges. Ictal discharges included generalized spike-wave, polyspike-wave, bilateral sharp wave, generalized delta, and generalized beta activity. Children with epileptic drops (group I) were similar to children with nonepileptic drops (group II) with respect to age, sex, number of recorded episodes, and presence of mental retardation or other abnormalities on neurologic examination. Group I patients had a significantly higher prevalence of ictal changes in facial expression, subtle myoclonic extremity movements, generalized interictal EEG discharges, and other seizure types. Drops characterized by rapid head descent followed by slow recovery to the upright position were significantly more common in group I patients, whereas drops in which the velocity of recovery matched that of head descent (head nods) were equal in the two groups. Repetitive nods (head bobs) were observed exclusively in group II patients. These clinical and electrophysiologic features may assist in differentiating epileptic from nonepileptic head drops in children.     

Identification of ictal foci by EEG and MR apparent diffusion coefficient map in a case of human herpesvirus 6-associated encephalopathy

We report here a 1-year-old boy with human herpesvirus 6 (HHV 6) -associated encephalopathy. On the 3rd day of fever, he had a generalized tonic seizure followed by mild disturbance of consciousness, which recovered completely the next day. Two days later, he had skin rash of exanthema subitum, and his consciousness declined frequently. EEG demonstrated rhythmic wave bursts originating from central areas bilaterally, followed by a generalized spike-and-wave complex which was associated with disturbed consciousness. We made the diagnosis of a status of complex partial seizures. Because the focal discharge on ictal EEG, MRI was performed. In the subcortical white matter of the frontal-parietal lobes, there were high signals on diffusion-weighted MRI, the apparent diffusion coefficient of which was much lower than that of normal controls. The affected areas soon disappeared with improvement of clinical symptoms. The transient MRI findings may indicate reversible cytotoxic brain edema. He showed no neurological sequelae as yet.     

A case of infantile epileptic apnea with congenital brain anomaly

Two months-old girl with psychomotor retardation had aminophylline-resistant apnea attacks and was investigated by video-EEG recording. She had hypogenesis of cerebral cortex and cerebellum and complete agenesis of corpus callosum. Left hemispheric 2 Hz rhythmic delta wave burst originating from the posterior temporal area lasted about 20 seconds, and was followed by an apnea attack persisting for 30 seconds. During the apnea attack, the basic activity of EEG was suppressed. The diagnosis of epileptic apnea was made, and the attacks were controlled with valproate sodium. Reports of cases of brain anomaly presenting with epileptic apnea are rare and this interesting case provided a clue to the pathomechanism of this condition.     

Patterns of EEG frequency content during experimental transient ischaemia in subhuman primates

EEGs were recorded with depth electrodes in 8 monkeys undergoing transient middle cerebral artery ligation. Electrodes measured EEG, cerebral blood flow (CBF), and tissue oxygen simultaneously during and after occlusion. An EEG frequency analysis was performed, Electrode sites were examined microscopically, and infarction size, tissue vacuolization index, and neuronal morphology were described quantitatively. Serial neurological examinations were performed. Two patterns of EEG frequency change were delineated, dependent upon degree of ischaemia. Mild ischaemia, as indicated by less severe clinical deficits, higher CBF during occlusion, and minor pathological changes was associated with large increases in slow EEG activity and decreases in fast EEG activity during occlusion, with recovery of slow activities to baseline, but continued suppression of fast activities 24 h later. Severe ischaemia was associated with suppression of both fast and slow frequencies during occlusion, with slow activities returning to baseline and fast activities remaining suppressed 24 h later. The best quantitative EEG indicator of severity of ischaemia was suppression of slow wave activity during occlusion. The best EEG indicator that an ischaemic event had occurred24 h previously was continued suppression of fast EEG activities. These data may be helpful in the design of EEG frequency analysis studies for monitoring the time course of human cerebral ischaemia and for retrospective diagnosis of transient ischaemic attacks (TIAs).     

Patterns of EEG frequency content during experimental transient ischaemia in subhuman primates

EEGs were recorded with depth electrodes in 8 monkeys undergoing transient middle cerebral artery ligation. Electrodes measured EEG, cerebral blood flow (CBF), and tissue oxygen simultaneously during and after occlusion. An EEG frequency analysis was performed. Electrode sites were examined microscopically, and infarction size, tissue vacuolization index, and neuronal morphology were described quantitatively. Serial neurological examinations were performed. Two patterns of EEG frequency change were delineated, dependent upon degree of ischaemia. Mild ischaemia, as indicated by less severe clinical deficits, higher CBF during occlusion, and minor pathological changes was associated with large increases in slow EEG activity and decreases in fast EEG activity during occlusion, with recovery of slow activities to baseline, but continued suppression of fast activities 24 h later. Severe ischaemia was associated with suppression of both fast and slow frequencies during occlusion, with slow activities returning to baseline and fast activities remaining suppressed 24 h later. The best quantitative EEG indicator of severity of ischaemia was suppression of slow wave activity during occlusion. The best EEG indicator that an ischaemic event had occurred 24 h previously was continued suppression of fast EEG activities. These data may be helpful in the design of EEG frequency analysis studies for monitoring the time course of human cerebral ischaemia and for retrospective diagnosis of transient ischaemic attacks (TIAs).     

Consciousness disturbance caused by iodoform absorption in a patient with decubitus ulcer topically treated with iodoform-gauze]

A 76-year-old man with supranuclear palsy, developed consciousness disturbance followed by the treatment of decubitus ulcer in the sacral region using iodoform-gauze. He was semicoma and tachycardia. His pupils were miotic and light reflexes were absent. EEG demonstrated diffuse and random slow activities. Plasma concentration of free iodine was high (151 micrograms/dl), but the other laboratory findings including thyroid functions were normal. He was diagnosed as suffering from iodoform poisoning. The symptoms and laboratory abnormalities of the patient recovered soon after the removal of iodoform-gauze. Although iodoform has been widely used for the treatment of wounds, there are few case reports of its side effects, such as consciousness disturbance, delirium, headache and tachycardia.