Donald M. Olson

Detection of seizure-like movements using a wrist accelerometer

Caregivers of people with epilepsy are commonly concerned about unwitnessed seizures causing injury and even death. The goal of this study was to determine if a wrist-worn motion detector could detect tonic-clonic seizures. Individuals admitted for continuous video/EEG monitoring wore a wristwatch-size device that was programmed to detect rhythmic movements such as those that occur during tonic-clonic seizures. When such movement was detected, the device sent a Bluetooth signal to a computer that registered the time and duration of the movements. Recorded detections were compared with the routinely recorded video/EEG data. Six of 40 patients had a total of eight tonic-clonic seizures. Seven of the eight seizures were detected. Nonseizure movements were detected 204 times, with opportunity for canceling transmission by the patient. Only one false detection occurred during sleep. In principle, this device should allow caregivers of people with tonic-clonic seizures to be alerted when a seizure occurs.

ELECTROCORTICOGRAPHIC CONFIRMATION OF FOCAL POSITRON EMISSION TOMOGRAPHIC ABNORMALITIES IN CHILDREN WITH INTRACTABLE EPILEPSY

Summary: The relationship between focal disturbances of glucose utilization demonstrated by positron emission tomography (PET) and electrophysiologic abnormalities defined by intraoperative electrocorticography (ECoG) was studied in eight children (aged 13 months to 12 years) who underwent cortical resection because of intractable seizures. None of the children had pure temporal lobe epilepsy. Computed tomography (CT) and/or magnetic resonance imaging (MRI) were normal in four of the eight children. The scalp electroencephalogram (EEG) showed lateralized interictal epileptiform abnormalities in all eight and lateralized ictal onset in five of eight. In seven children, interictal PET showed focal hypometabolism; the eighth child had focal, ictal hypermetabolism. ECoG at the time of surgery showed epileptiform spiking, slowing, and/or suppression of normal background activity that in every case corresponded to the focus on PET scan. The ECoG findings support the notion that in children with epilepsy focal metabolic abnormalities on PET correspond to electrophysiologically abnormal areas of cortex, which are presumably also the epileptogenic regions. Such areas can appear normal on anatomic imaging studies (CT and MRI). When ictal scalp EEG data are ambiguous or contradictory, PET provides a less invasive means than chronic grid or depth electrode recording for evaluating whether a localized epileptogenic area exists.

Pediatric psychogenic nonepileptic seizures: A study of assessment tools

The goal of this study was to identify assessment tools and associated behavioral domains that differentiate children with psychogenic nonepileptic seizures (PNES) from those with epilepsy. A sample of 24 children with PNES (mean age 14.0 years, 14 female), 24 children with epilepsy (mean age 13.6 years, 13 female), and their parents were recruited from five epilepsy centers in the United States. Participants completed a battery of behavioral questionnaires including somatization, anxiety, and functional disability symptoms. Children with PNES had significantly higher scores on the Childhood Somatization and Functional Disability Inventories, and their parents reported more somatic problems on the Child Behavior Checklist (CBCL). Depression, anxiety, and alexithymia instruments did not differentiate the groups. Measures of somatization and functional disability may be promising tools for differentiating the behavioral profile of PNES from that of epilepsy. Increased somatic awareness and perceived disability emphasize the similarity of PNES to other pediatric somatoform disorders.

Evaluation of Children for Epilepsy Surgery

There are three main components to the evaluation of children who are candidates for epilepsy surgery: (1) confirmation of the epileptic nature of the seizures, (2) establishing the medical intractability of the child’s epilepsy and (3) localization of the epileptogenic zone. Differentiating epileptic from nonepileptic events requires careful review of the history and the electroencephalogram. Electroencephalographic recording of the habitual seizures usually suffices to confirm the epileptic or nonepileptic nature of the events. Medical intractability is established by assuring that antiepileptic medications appropriate for the child’s particular epilepsy syndrome have been used and have been titrated to maximum tolerance before being deemed ineffective. Confident localization of the epileptogenic zone requires that multiple findings such as behavior during the seizure, ictal and interictal EEG, and cerebral imaging studies provide data that are convergent with respect to a likely area of seizure onset.

Success of ambulatory EEG in children.

Summary Continuous ambulatory EEG (AEEG) monitoring is a methodused to (1) determine seizure type and location of seizure onset, and (2) todiscriminate between epileptic and nonepileptic events. This study wasperformed to determine how successful AEEG would be in recording seizures whenthe events were reported to occur at least 3 days per week. AEEGs of childrenwho were patients at Children’s Hospital Oakland between December 1993and June 1997 were reviewed to see why the recordings were performed and todetermine whether typical seizures were recorded. Children who had seizurelikeevents needed to have typical spells 3 days or more per week to justifyobtaining AEEG. Most AEEGs were performed to discriminate between epilepticand nonepileptic seizures. A total of 167 children underwent AEEG recording.Ten were recorded to determine whether they were having frequent subtleseizures or frequent interictal epileptiform discharges. The remaining 157patients had discrete events. A total of 140 children (89%) had their typicalspells recorded. A total of 107 of these children (76%) had nonepilepticevents. Average duration of recording was 1.9 days. AEEG is very successful inrecording children’s seizurelike events when parents report events occurat least 3 days per week. The procedure is well tolerated and there are fewtechnical problems that prolong recordingtime.

Hypnosis-provoked nonepileptic events in children

OBJECTIVE The purpose of this study was to describe the use of hypnotic suggestion as a means of precipitating nonepileptic events in children while they are undergoing video electroencephalographic monitoring (VEEG) for differential diagnosis of seizurelike behavior. METHODS Nine children aged 8-16 years were referred for VEEG to differentiate between epileptic seizures and nonepileptic events. All subjects underwent psychiatric consultation. Hypnosis was attempted in all subjects to try to provoke typical seizurelike events. RESULTS In eight of nine patients, their typical seizurelike events were provoked by hypnosis. In all eight children, video and EEG analysis of the provoked events demonstrated them to be nonepileptic. No epileptiform abnormalities were present on interictal EEGs. No epileptic seizures occurred. CONCLUSION Hypnosis is a useful and ethical means of provoking psychogenic nonepileptic events in children. Hypnotic suggestion should be considered as a provocative method when possibly psychogenic nonepileptic events have not occurred spontaneously during diagnostic evaluation.

Short Duration of Benign Partial Epilepsy in Infancy

It has previously been reported that benign partial epilepsy in infancy constitutes up to 29% of the epilepsies presenting in the first 2 years of life. To determine the proportion of benign partial epilepsy in our epilepsy population, we retrospectively reviewed 331 patients with greater than two afebrile seizures in the first 2 years of life between 1993 and 2000. Inclusion criteria were (1) partial seizures with or without secondary generalization, (2) normal development, (3) no other neurologic abnormalities, (4) normal interictal electroencephalograms (EEGs), and (5) good response to treatment. Exclusion criteria included seizures that (1) were caused by acute central nervous system insult, (2) occurred only within the first month of life, and (3) lasted longer than 30 minutes. Of 331 patients, 22 (6.6%) fulfilled the criteria with a minimum of 2 years and a mean of 4 years of follow-up off antiepilepsy drug treatment. Six (27%) had complex partial seizures, and 16 (73%) had complex partial seizures with secondary generalization. Neuroimaging studies were normal in all patients. Of the 6 patients with ictal EEGs, 3 had a temporal lobe focus, 1 had an occipital lobe focus, and the remaining 2 had dual foci. Median onset was 4.0 months (range 0.8-9.3). Seizures remitted within 4 months in 20 (91%). Mean duration of seizure persistence was 2.1 months (range 0-8.3) and was longer in treated patients. Median age at last seizure was 6.4 months (range 2-18). Nineteen were treated with antiepilepsy drugs. At last follow-up (mean duration of 52.2 months), all patients were seizure free and off antiepilepsy drugs. Benign partial epilepsy in infancy is an epilepsy syndrome of short duration and is easily recognized using accepted classification criteria. Benign partial epilepsy in infancy appears to be an idiopathic localization-related epilepsy with a favorable prognosis. The incidence in our population is not as common as previously reported. Based on our findings, we suggest weaning of antiepilepsy drugs 6 months after seizure onset. (J Child Neurol 2002;17:440-445).

Epilepsy surgery following brain tumor resection in children

OBJECT Intractable epilepsy following successful brain tumor surgery in children may have several underlying causes such as residual tumor, cortical dysplasia, and gliosis. The authors reviewed the cases of children who had previously undergone resection of a brain tumor only to have medically refractory seizures postoperatively. METHODS The authors performed a retrospective case review of 9 children who underwent brain tumor surgery 2-13 years before undergoing a second surgery to try and control their seizures. RESULTS Eight of 9 children had seizures at the time of tumor presentation. Tumor types included ganglioglioma, dysembryoplastic neuroepithelial tumor, pilocytic astrocytoma, oligodendroglioma, ependymoma, and choroid plexus papilloma. All patients achieved a seizure-free interval before intractable seizures recurred. After the second operation, 3 children were seizure free, 1 only had auras, 2 had rare complex partial seizures, and 3 continued to have relatively frequent seizures, although the frequency and severity were reduced. Seven of 9 patients had pathology showing residual tumor. CONCLUSIONS Epilepsy surgery following earlier brain tumor surgery can provide substantial benefit with reduced seizure number and severity. Despite reassuring brain imaging results, residual tumor was present more often than expected in pathological specimens.

Electroencephalography in holoprosencephaly: Findings in children without epilepsy

OBJECTIVE To evaluate the electroencephalographic characteristics of patients with holoprosencephaly (HPE) without epilepsy. METHODS We evaluated the electroencephalograms (EEGs) of 18 children with HPE who lacked a history of seizures. Neuroimaging studies were assessed for severity of HPE and thalamic non-separation and the presence of dorsal cysts and cortical malformations. RESULTS Hypersynchronous theta activity occurred in 50 and 60% of EEGs during wakefulness or drowsiness/sleep, respectively, and correlated with the grade of thalamic non-separation (p<0.05). Hypersynchronous beta activity during sleep occurred in 41% of EEGs. Posterior amplitude attenuation occurred in 33% of EEGs and correlated with the presence of a dorsal cyst (p</=0.0004). Photic driving responses were seen in 50% of the EEGs. If a dorsal cyst was present, the responses were anteriorly displaced. Epileptiform activity was noted in EEGs of 5 patients and did not correlate with the incidence of clinical seizures. CONCLUSIONS Hypersynchronous activity was present frequently in EEGs of HPE patients, possibly attributable to incomplete separation of the thalami and hemispheres. Dorsal cysts were associated with posterior amplitude attenuation and anterior displacement of the photic response. In this selective cohort, the presence of epileptiform activity was not a risk factor for seizures. SIGNIFICANCE To date, this is the largest study of EEGs in children diagnosed with HPE without seizures. This study complements our earlier clinical and neuroradiologic studies by providing neurophysiologic data that serves to enhance our understanding of this complex, rare disorder.

Electroencephalographic abnormalities in infants with hypoplastic left heart syndrome

Electroencephalography (EEG) was performed on 16 neonates between 38-45 weeks conceptional age with hypoplastic left heart syndrome (HLHS). The findings were compared blindly with EEGs recorded from 16 infants with other congenital heart defects and 15 infants referred for EEGs with noncardiac diagnoses or problems. EEGs from HLHS infants demonstrated significantly decreased quiet sleep and increased indeterminate sleep, an abnormally discontinuous tracing in active and indeterminate sleep, and lack of response to stimulation. No significant differences were present in the amount of active sleep, sharp waves, focal slowing, or rhythmic theta activity. The distinctive abnormalities were unrelated to arterial blood gases or treatment with prostaglandin E at recording. Four HLHS infants had repeat recordings performed; there were serial increases in quiet sleep, decreases in indeterminate sleep, and improved continuity in all patients. Certain EEG abnormalities occur more frequently in infants with HLHS than in patients with other cardiac defects or noncardiac problems. These findings may result from the early onset of heart failure and abnormal cerebral perfusion due to hypoplasia of the ascending aorta and great arteries, conditions commonly associated with HLHS.