Risk factors for carbamazepine elevation and toxicity following epilepsy surgery

A proportion of patients undergoing epilepsy surgery, and receiving carbamazepine (CBZ), experience significant elevations in CBZ plasma concentrations, some with associated CBZ toxicity. The objective of this study was to identify significant risk factors for elevations (>12 microg/ml) in CBZ concentrations and CBZ-induced toxicity following epilepsy surgery.

METHODS

We retrospectively examined charts of 74 inpatients (31 children and 43 adults) chronically receiving CBZ and undergoing epilepsy surgery between January 1996 and June 2000. Patient demographics, medications, type of surgery, seizure history, adverse events, CBZ doses and concentrations were evaluated.

RESULTS

51.2% of adults and 51.6% of pediatric patients had drug elevations. In the pediatric group, 12.9% had symptoms of toxicity compared to 9.3% in the adult group. Five risk factors-pre-operative CBZ dose, fentanyl dose, surgery day CBZ concentration, body weight, and blood loss-were related to post-operative CBZ concentrations. Three risk factors: age <18 years, pre-operative CBZ dose, and the surgery day CBZ (immediate pre-operative) concentration, were significantly related to the outcome measure of abnormal CBZ concentration (>12 microg/ml). Two variables significantly related to toxicity were average post-operative CBZ dose and the surgery day CBZ concentration. Increases in concentrations occurred at a mean 33+/-13.7 h (range: 11-74 h) after surgery.

DISCUSSION

Based upon our results in patients with one or more risk factors, we suggest that reduction of post-operative CBZ doses be considered.

Resective surgery to treat refractory status epilepticus in children with focal epileptogenesis

Prolonged high-dose suppressive therapy (HDST) is a mainstay in the management of refractory status epilepticus (RSE), albeit with high morbidity and mortality. The authors studied 10 patients who were carefully selected for epilepsy surgery after failing prolonged (>2 weeks) HDST. Status epilepticus was stopped acutely in all of them with no mortality and no substantial morbidity. At follow-up (median 7 months), 7 (70%) of 10 patients were seizure free, and 3 (30%) of 10 had significant improvement in their epilepsy.

Lateralizing signs during seizures in focal epilepsy

This article reviews lateralizing semiological signs during epileptic seizures with respect to prediction of the side of the epileptogenic zone and, therefore, presurgical diagnostic value. The lateralizing significance of semiological signs and symptoms can frequently be concluded from knowledge of the cortical representation. Visual, auditory, painful, and autonomic auras, as well as ictal motor manifestations, e.g., version, clonic and tonic activity, unilateral epileptic spasms, dystonic posturing and unilateral automatisms, automatisms with preserved responsiveness, ictal spitting and vomiting, emotional facial asymmetry, unilateral eye blinking, ictal nystagmus, and akinesia, have been shown to have lateralizing value. Furthermore, ictal language manifestations and postictal features, such as Todd's palsy, postictal aphasia, postictal nosewiping, postictal memory dysfunction, as well as peri-ictal water drinking, peri-ictal headache, and ipsilateral tongue biting, are reviewed. Knowledge and recognition of semiological lateralizing signs during seizures is an important component of the presurgical evaluation of epilepsy surgery candidates and adds further information to video/EEG monitoring, neuroimaging, functional mapping, and neuropsychological evaluation.

Calcium-sensitive potassium channelopathy in human epilepsy and paroxysmal movement disorder

The large conductance calcium-sensitive potassium (BK) channel is widely expressed in many organs and tissues, but its in vivo physiological functions have not been fully defined. Here we report a genetic locus associated with a human syndrome of coexistent generalized epilepsy and paroxysmal dyskinesia on chromosome 10q22 and show that a mutation of the alpha subunit of the BK channel causes this syndrome. The mutant BK channel had a markedly greater macroscopic current. Single-channel recordings showed an increase in open-channel probability due to a three- to fivefold increase in Ca(2+) sensitivity. We propose that enhancement of BK channels in vivo leads to increased excitability by inducing rapid repolarization of action potentials, resulting in generalized epilepsy and paroxysmal dyskinesia by allowing neurons to fire at a faster rate. These results identify a gene that is mutated in generalized epilepsy and paroxysmal dyskinesia and have implications for the pathogenesis of human epilepsy, the neurophysiology of paroxysmal movement disorders and the role of BK channels in neurological disease.

Identification of candidates for epilepsy surgery in patients with tuberous sclerosis

The authors reviewed preoperative MRI and EEG findings in relation to postsurgical outcome in 17 patients with refractory epilepsy due to tuberous sclerosis complex (TSC). Resecting concordant MRI (main tuber) and EEG abnormalities offered seizure freedom (8/9, 89%; median follow-up 25 months) comparable to other focal etiologies. Patients with nonconcordant MRI and EEG findings did less well (3/8, 38%, seizure free; p = 0.027, OR = 13).

Seizure outcome after epilepsy surgery in patients with normal preoperative MRI

OBJECTIVE

To determine outcome after epilepsy surgery in patients with normal preoperative magnetic resonance imaging (MRI).

METHODS

24 adult and paediatric patients with normal preoperative MRIs were studied. They underwent epilepsy surgery between 1994 and 2001 and had at least one year of follow up.

RESULTS

At the most recent follow up, nine patients (37%) were seizure-free and 18 (75%) had at least a 90% reduction in seizure frequency with weekly or monthly seizures. Seizure freedom was not significantly different after resections in frontal (5/9) or temporal regions (4/13) (p = 0.24, Fisher's exact test), or among patients with or without localising features on EEG, PET, or ictal SPECT. Subdural grids, used in 15 of 24 patients, helped tailor resections but were not associated with differences in outcome. Histopathology showed cortical dysplasia in 10 patients (42%), non-specific findings in 13 (54%), and hippocampal sclerosis in one (4%). Cortical dysplasia was seen in seven patients with frontal resection (78%) and non-specific findings in nine (69%) with temporal resection. Seizure outcome did not differ on the basis of location of resection or histopathology.

CONCLUSIONS

While these results were less favourable than expected for patients with focal epileptogenic lesions seen on MRI, they represented worthwhile improvement for this patient population with high preoperative seizure burden. In this highly selected group, no single test or combination of tests further predicted postoperative seizure outcome.

Lateralizing signs during seizures in infants

OBJECTIVE

To identify lateralizing features during seizures in infants and assess their reliability.

METHODS

Infants were included if they had video-EEG monitoring at our institution, and were seizure-free for at least 12 months after epilepsy surgery. Lateralizing signs and seizure symptomatology were classified based on blinded video review.

RESULTS

We analyzed 100 seizures from 19 infants (1 to 32, mean 13 months of age) (1 to 14 seizures per patient). Potential lateralizing signs were seen in 58 seizures from 12 infants, including unilateral clonic jerking (8 patients); forced, sustained tonic version of the eyes to one side (7 patients); predominantly unilateral infantile spasms (5 patients); unilateral tonic stiffening of an arm and leg (2 patients); nystagmus (2 patients) and postictal hemiparesis (1 patient). Except for tonic eye version, each of the signs was contralateral to the hemisphere of seizure-onset in all but one patient who had predominantly ipsilateral spasms and clonic arm activity. Tonic eye version was contralateral in 3 patients, ipsilateral in 1 patient, and toward either side in different seizures in 3 patients.

CONCLUSION

Reliable lateralizing signs included focal clonic activity and predominantly unilateral spasms. Focal tonic activity, nystagmus and postictal hemiparesis were also consistently contralateral but were observed only in few patients. Tonic eye version was unreliable and could not be used to lateralize seizure onset. The sequence of eye and head version evolving to generalized tonic clonic convulsions was not seen in this age group.

Ictal SPECT in children with partial epilepsy due to focal cortical dysplasia

We studied the usefulness of ictal single-photon emission computed tomography in the presurgical evaluation of children with partial epilepsy resulting from focal cortical dysplasia. Fifteen children, age 1-18 years, were identified with partial epilepsy caused by focal cortical dysplasia (confirmed by histology) who underwent subtraction ictal single-photon emission computed tomography during presurgical evaluation. All children later underwent surgery at the Cleveland Clinic Epilepsy Center between 1996 and 2000. The findings of ictal single-photon emission computed tomography and brain positron emission tomography were classified as localized when "localizing and concordant" with the surgical resection site, nonconcordant when "localizing but not concordant" with the surgical resection, or nonlocalized when "no well-localized region of ictal hyperperfusion was observed on the difference image". In 15 patients, age 1.5-18 years (median age 8 years), epilepsy was classified as frontal in 7, posterior temporal/occipital in 3, temporal in 2, multilobar in 2, and parietal in 1. Of 15 patients, preoperative magnetic resonance imaging revealed focal cortical dysplasia in 11, positron emission tomography was localized in 9, and ictal single-photon emission computed tomography was localized in 8 patients. In 4 patients with normal magnetic resonance imaging but scalp electroencephalographic findings of partial epilepsy, ictal single-photon emission computed tomography and positron emission tomography were localized in 3 each. Fourteen patients were monitored for 6-39 months (mean 20 months). Six of 7 patients (85%) with localized ictal single-photon emission computed tomography compared with 4 of 7 (57%) with nonconcordant/nonlocalized ictal single-photon emission computed tomography had no seizures at follow-up. In 4 patients with normal magnetic resonance imaging, 3 patients with localized ictal single-photon emission computed tomography were free of seizures compared with 1 with nonconcordant ictal single-photon emission computed tomography who continued to have seizures. Ictal single-photon emission computed tomography is a useful adjunctive test in presurgical evaluation of children with refractory partial epilepsy due to focal cortical dysplasia, especially when brain magnetic resonance imaging is normal.

Lateralizing value of Todd's palsy in patients with epilepsy

The authors retrospectively investigated the value of Todd's palsy (TP) in lateralizing the hemisphere of seizure onset in patients admitted for video-EEG monitoring in a tertiary epilepsy center. In 29 patients, a postictal hemiparesis was observed. TP always occurred contralateral to the epileptogenic hemisphere in 27 patients (93%). In the remaining two patients, the seizure onset could not be lateralized. In some patients, TP occurred after a seizure without focal motor features or secondary generalization.

Ictal spitting: clinical and electroencephalographic features

PURPOSE

To identify clinical and EEG correlates of ictal spitting automatisms and to assess their reliability in indicating the hemisphere of seizure onset.

METHODS

The epilepsy-monitoring database (1994-2002) of the Cleveland Clinic Foundation (CCF) was searched for patients with a definite history of ictal spitting. All available documents of the patients, particularly their original video and EEG data, were reviewed.

RESULTS

Twelve (0.3%) of the approximately 4000 patients had a documented history of ictal spitting. In seven of them, 15 seizures with spitting automatisms were recorded. All of them started with an aura or arousal out of sleep. In six of the seven patients (12 of 15 seizures), EEG onset was clearly lateralized to the right, nondominant hemisphere. Spitting occurred at a median time of 21 s after EEG seizure onset. At that time, predominantly fast, high-amplitude theta (5-7 Hz) was seen in the hemisphere of seizure onset, maximum temporal. In all but one of the total 12 patients, the epileptogenic zone was in the temporal lobe. In nine of the 12 patients, seizure onset was in the non-language-dominant hemisphere. Two patients had seizures arising from the language-dominant hemisphere; in another patient, the side of the seizure onset could not be determined.

CONCLUSIONS

Ictal spitting is an uncommon feature of epileptic seizures. Although the symptomatogenic area is probably outside the temporal lobe, it is most frequently seen in temporal lobe epilepsy of the right, nondominant hemisphere.

Complex partial seizures of frontal lobe onset statistical analysis of ictal semiology

OBJECTIVE

To identify the ictal semiology of complex partial seizures originating from the frontal lobe (FLCPS) and mesial temporal lobe (MTLE) in patients who became seizure free after surgery.

METHODS

We analysed 149 seizures from 42 patients, 28 with MTLE (75 seizures) and 14 with FLCPS (74 seizures) seizure free for at least 1 year after surgery. Fifty-eight symptoms and signs were looked for in every seizure and their time of onset and ending noted. Statistical analysis was then used to define the frequency, time of onset and cluster analysis of these symptoms/signs.

RESULTS

Epigastric aura was more frequent in MTLE while an aura of a general body sensation or indescribable feeling occurred only in FLCPS. Alimentary automatisms were more common and occurred earlier in MTLE (P<0.001). Perseverative automatisms, retching and vomiting occurred exclusively in MTLE while bicycling movements occurred only in FLCPS. Abdominal, psychic or olfactory aura followed by behavioural arrest, alimentary automatisms, repetitive distal upper extremity movements, complete loss of consciousness, looking around and whole body movements were typical of MTLE. Repetitive coarse upper extremity movements, complete loss of consciousness, complex motor and hypermotor activity were typical of FLCPS.

CONCLUSION

The earliest symptoms and signs as well as their order of appearance allow one to distinguish between complex partial seizures arising from the frontal lobe and mesial temporal lobe.

Paroxysmal nonepileptic events in children and adolescents

OBJECTIVE

Paroxysmal nonepileptic events (PNEs) are frequently encountered in children and adolescents; however, there is little information concerning the relative frequency of various types of these disorders. We report our experience with PNEs in a group of children and adolescents who underwent prolonged video-electroencephalographic monitoring.

METHODS

During a 6-year period, 883 patients were monitored in the Pediatric Epilepsy Monitoring Unit and 134 patients (15.2%) were documented to have PNEs on the basis of a typical spell recorded during monitoring. Their hospital charts were reviewed and videotapes of these events were analyzed.

RESULTS

Patients were divided into 3 age groups: 1) the Infant, Toddler, and Preschool Group (2 months-5 years) that comprised 26 patients. The most common diagnoses were stereotyped movements, hypnic jerks, parasomnias, and Sandifer syndrome. Concomitant epilepsy was present in 12 patients (46%). 2) The School-Age Group (5-12 years) consisted of 61 patients. The most frequent diagnoses were conversion disorder (psychogenic seizures), inattention or daydreaming, stereotyped movements, hypnic jerks, and paroxysmal movement disorders. Fifteen patients (25%) had concomitant epilepsy. 3) The Adolescent Group (12-18 years) consisted of 48 patients, of whom 40 patients (83%) were diagnosed with conversion disorder. Nine patients (19%) had concomitant epilepsy.

CONCLUSIONS

In our patients with PNEs, conversion disorder was seen in children >5 years old and its frequency increased with age, becoming the most common type of PNEs among adolescents. In adolescents, conversion disorder was more common in females, whereas males predominated in the school-aged group. Concomitant epilepsy with nonepileptic events occurred in all 3 age groups to a varying extent.

Hypomotor seizures in infants and children

PURPOSE

Hypomotor seizures (characterized by diminished behavioral activity with indeterminate level of consciousness) have been identified as an important seizure type in infants. Our goal was to investigate further the clinical and EEG features of hypomotor seizures.

METHODS

We retrospectively reviewed 110 hypomotor seizures from 34 patients recorded with video-EEG.

RESULTS

Twenty-seven (79%) patients were younger than 48 months, and seven (21%) were aged 4 to 15 years. Seventy-one (64%) seizures had regional or lateralized EEG onset, arising predominantly from temporal or parietal lobe regions. The other 39 (35%) seizures had generalized onset, usually with abrupt onset of diffuse rhythmic high-amplitude theta activity or diffuse electrodecrement and only rarely (two patients) with slow spike-wave complexes or 3-Hz spike-wave complexes. Hypomotor seizures with generalized EEG onset were significantly shorter than those with regional or lateralized onset (p = 0.01, GEE model). Unsustained head or eye movements and subtle mouth automatisms were commonly seen in hypomotor seizures with either focal or generalized onset. Seventeen percent of hypomotor seizures with focal onset evolved to include version of head and eyes or jerking of one arm, whereas 2% of generalized hypomotor seizures evolved to a cluster of spasms.

CONCLUSIONS

Hypomotor seizures may be either focal or generalized. Regional EEG onsets were most often temporal or parietal, suggesting that focal hypomotor seizures may be a bland form of "complex partial" seizures with no or minimal automatisms, seen predominantly in infants. Generalized hypomotor seizures were rarely associated with an ictal pattern of generalized spike-wave complexes, suggesting a different mechanism from absence seizures seen later in life.

Intractable epilepsy in vascular congenital hemiparesis: clinical features and surgical options

Forty-one patients with vascular congenital hemiplegia and intractable epilepsy were reviewed. Most had severe hemiparesis, mental retardation, porencephaly, and focal epilepsy. Thirty-three were considered surgical candidates and 25 underwent surgery. Seizure freedom and significant seizure reduction were achieved in 12 of 13 patients after functional hemispherectomy, 4 of 6 after temporal lobectomy, 2 of 2 with extratemporal focal resections, 1 of 3 with corpus callosotomy, and 1 with porencephalic cyst drainage.

Complications of invasive video-EEG monitoring with subdural grid electrodes

OBJECTIVE

To evaluate the risk factors, type, and frequency of complications during video-EEG monitoring with subdural grid electrodes.

METHODS

The authors retrospectively reviewed the records of all patients who underwent invasive monitoring with subdural grid electrodes (n = 198 monitoring sessions on 187 patients; median age: 24 years; range: 1 to 50 years) at the Cleveland Clinic Foundation from 1980 to 1997.

RESULTS

From 1980 to 1997, the complication rate decreased (p = 0.003). In the last 5 years, 19/99 patients (19%) had complications, including two patients (2%) with permanent sequelae. In the last 3 years, the complication rate was 13.5% (n = 5/37) without permanent deficits. Overall, complications occurred during 52 monitoring sessions (26.3%): infection (n = 24; 12.1%), transient neurologic deficit (n = 22; 11.1%), epidural hematoma (n = 5; 2.5%), increased intracranial pressure (n = 5; 2.5%), and infarction (n = 3; 1.5%). One patient (0.5%) died during grid insertion. Complication occurrence was associated with greater number of grids/electrodes (p = 0.021/p = 0.052; especially >60 electrodes), longer duration of monitoring (p = 0.004; especially >10 days), older age of the patient (p = 0.005), left-sided grid insertion (p = 0.01), and burr holes in addition to the craniotomy (p = 0.022). No association with complications was found for number of seizures, IQ, anticonvulsants, or grid localization.

CONCLUSIONS

Invasive monitoring with grid electrodes was associated with significant complications. Most of them were transient. Increased complication rates were related to left-sided grid insertion and longer monitoring with a greater number of electrodes (especially more than 60 electrodes). Improvements in grid technology, surgical technique, and postoperative care resulted in significant reductions in the complication rate.

Focal cortical dysplasias in eloquent cortex: functional characteristics and correlation with MRI and histopathologic changes

PURPOSE

Focal cortical dysplasia (CD) is increasingly recognized as a common pathologic substrate of medically intractable epilepsy. As these lesions are often localized in the frontal lobe (therefore in potentially eloquent cortex), an understanding of the functional status of the involved region(s) and of its anatomic and pathologic correlates is of prime importance. The purpose of this study is to assess the function of focal CD in relation to magnetic resonance imaging (MRI) and histopathologic features.

METHODS

Eight patients operated on for medically intractable epilepsy with histologically proven focal CD involving putative eloquent cortex in the frontal lobe (perirolandic and Broca's areas) were included in the study. Functional regions (motor and language) and epileptogenic areas were assessed by extraoperative electrocorticographic recording and electrical cortical mapping. Cortical functions were correlated with the extent of epileptogenicity on electrocorticographic recordings, MRI features, and histologic characteristics.

RESULTS

Language or motor areas were colocalized with epileptogenic regions (n=6 of 8, 75%), but were not mapped in regions of increased signal on fluid-attenuated inversion recovery (FLAIR) MRI (when they were identified) on preoperative MRI (n=5 of 5, 100%). Histologically, balloon cells were almost exclusively found in nonfunctional regions with FLAIR MRI abnormalities. When resected, regions of motor cortex were characterized by cortical dyslamination, columnar disorganization, and dysmorphic neurons, but were devoid of balloon cells.

CONCLUSIONS

We found an absence of language or motor functions in perirolandic and Broca's areas that showed decreased epileptogenicity, histopathological evidence of CD with balloon cells and FLAIR MRI signal increase. Language and motor functions were present in epileptogenic and dysplastic areas with no balloon cells and no FLAIR signal abnormalities. These findings have implications on options for epilepsy surgery in patients with CD.

The relationship between sleep and epilepsy

Seizures occur extensively during sleep or on awakening in a substantial proportion of patients with epilepsy. Interictal epileptiform discharges are also influenced by sleep and sleep deprivation. Continuous spike-waves in slow-wave sleep are the hallmark of Landau-Kleffner syndrome and ESES (Electrical Status in Slow Sleep). Sleep deprivation is known to influence not only the occurrence but also the symptomatology of epileptic seizures. Sleep architecture and daytime alertness are influenced by seizures and antiepileptic medications. This review examines the clinical and basic science aspects of this relationship between sleep and epilepsy.

Efficacy of the ketogenic diet in focal versus generalized seizures

Most reports of the ketogenic diet have focused on its efficacy for generalized seizures. Few data are available regarding its effect on focal seizures. We retrospectively studied patients (mean = 7.5 years of age) with medically intractable epilepsy treated by the ketogenic diet. The predominant seizure types in each patient were classified as generalized (100 patients) or focal (34 patients) based on ictal electroencephalograms (EEGs) or seizure semiology and interictal EEG. A seizure reduction of more than 50% compared with baseline was seen in nine patients (27%) with focal seizures and 46 patients (46%) with generalized seizures at 3 months, in 10 patients (30%) with focal seizures and 46 patients (46%) with generalized seizures at 6 months, and in eight patients (24%) with focal seizures and 42 patients (42%) with generalized seizures at 12 months. Differences were not significant. Outcome tended to be better in patients younger than 12 years of age compared with the older age group, but the difference was significant at 6 months only. Our results suggest that some patients with intractable focal epilepsy may respond favorably to the ketogenic diet and that this option should be considered if epilepsy surgery is not possible.

Seizure outcome after functional hemispherectomy for malformations of cortical development

MRI features were correlated with postsurgical seizure outcome in patients with hemispheric malformations of cortical development (MCD). After functional hemispherectomy, 5 of 6 patients (83%) with hemimegalencephaly had persistent, although markedly improved, seizures; 5 of 6 patients (83%) with relative preservation of part of one lobe or atrophy were seizure free. Hemimegalencephaly and other types of hemispheric MCD appear to differ in prognosis for freedom from seizures after functional hemispherectomy.

Temporal lobe epilepsy due to hippocampal sclerosis in pediatric candidates for epilepsy surgery

OBJECTIVE

To characterize the clinical, EEG, MRI, and histopathologic features and explore seizure outcome in pediatric candidates for epilepsy surgery who have temporal lobe epilepsy (TLE) caused by hippocampal sclerosis (HS).

METHODS

The authors studied 17 children (4 to 12 years of age) and 17 adolescents (13 to 20 years of age) who had anteromesial temporal resection between 1990 and 1998.

RESULTS

All patients had seizures characterized by decreased awareness and responsiveness. Automatisms were typically mild to moderate in children and moderate to marked in adolescents. Among adolescents, interictal spikes were almost exclusively unilateral anterior temporal, as opposed to children in whom anterior temporal spikes were associated with mid/posterior temporal, bilateral temporal, extratemporal, or generalized spikes in 60% of cases. MRI showed hippocampal sclerosis on the side of EEG seizure onset in all patients. Fifty-four percent of children and 56% of adolescents had significant asymmetry of total hippocampal volumes, whereas the remaining patients had only focal atrophy of the hippocampal head or body. Subtle MRI abnormalities of ipsilateral temporal neocortex were seen in all children and 60% of adolescents studied with FLAIR images. On histopathology, there was an unexpectedly high frequency of dual pathology with mild to moderate cortical dysplasia as well as HS, seen in 79% of children and adolescents. Seventy-eight percent of patients were free of seizures at follow-up (mean, 2.6 years). A tendency for lower seizure-free outcome was observed in patients with bilateral temporal interictal sharp waves or bilateral HS on MRI. The presence of dual pathology did not portend poor postsurgical outcome.

CONCLUSIONS

TLE caused by HS similar to those in adults were seen in children as young as 4 years of age. Focal hippocampal atrophy seen on MRI often was not reflected in total hippocampal volumetry. Children may have an especially high frequency of dual pathology, with mild to moderate cortical dysplasia as well as HS, and MRI usually, but not always, predicts this finding. Postsurgical seizure outcome is similar to that in adult series.

Symptomatic or cryptogenic partial epilepsy of childhood onset: fourteen-year follow-up

This study reports on the seizure and psychosocial outcome of 29 patients with electroclinically well-defined childhood-onset symptomatogenic or cryptogenic partial epilepsy with complex partial seizures who were followed prospectively over 14 years. Many were refractory at the time of enrollment. At 14-year follow-up, we acquired information on seizure type and frequency, psychiatric history, substance abuse, criminal activity, in addition to educational, vocational, and marital status through chart reviews and/or structured telephone interviews. Sixteen patients were only treated medically. They were divided by their following responses to medications: eight patients with less than one seizure per month were in the medically responsive group and eight patients with at least one seizure per month constituted the medically refractory group. Thirteen patients underwent focal resection for medically refractory epilepsy. Medically refractory patients displayed worse educational, vocational, social, and behavioral outcomes than medically responsive patients. Behavioral abnormalities persisted or evolved in five medically refractory patients when they became seizure free. Other studies have indicated that patients with medically refractory complex partial seizures have poor psychosocial outcomes. Although behavioral problems can occur even when seizures are well controlled, their early detection and treatment may be essential to the improvement of psychosocial outcomes.

Mental retardation in pediatric candidates for epilepsy surgery: the role of early seizure onset

PURPOSE

We sought to determine whether early age at seizure onset is a risk factor for mental retardation, independent of etiology. Assessment of risk for mental retardation with continued uncontrolled seizures plays a role in considerations of timing for epilepsy surgery. Previous studies have indicated that onset of seizures in the first years of life may be a risk factor for mental retardation, but the etiologies of the epilepsies were not included in the analyses.

METHODS

Intellectual function was assessed at ages 2-20 years during presurgical evaluation in 100 patients with intractable epilepsy due to focal lesions limited to part of one lobe of the brain. Mental retardation (MR) was defined as Full-Scale Intelligence Quotient (FSIQ) < or =70. The age at seizure onset and the seizure frequency were obtained retrospectively.

RESULTS

Younger ages at seizure onset were associated with lower FSIQ scores, and mean FSIQ was also significantly lower for patients with onset of epilepsy at < or =24 months of age (74.0 +/- 21.5) versus that in patients with onset of epilepsy later in life (87.8 +/- 18.8; p = 0.005). The frequency of patients with MR was significantly higher for patients with seizure onset at < or =24 months of age (15 of 33, 46%) than for patients with seizure onset later in life (eight of 67, 12%; p < 0.001). This difference persisted within etiologic subgroups. For patients with focal malformation of cortical development, MR was seen in eight (50%) of 16 patients with seizure onset at < or =24 months versus two (10%) of 20 patients with seizure onset at >24 months (p < 0.001); for patients with tumor, MR was seen in four (50%) of eight patients with seizure onset at < or =24 months versus four (13%) of 30 patients with seizure onset at >24 months (p = 0.003); and for patients with hippocampal sclerosis, MR was seen in two (28%) of seven patients with seizure onset at < or =24 months versus none of 30 patients with seizure onset at >24 months (NS). Within the subgroup with daily seizures, MR was present in 13 (65%) of 20 patients with seizure onset at < or =24 months versus five (17%) of 29 patients with seizure onset later in life (p = 0.001).

CONCLUSIONS

These results indicate that onset of intractable epilepsy within the first 24 months of life is a significant risk factor for MR, especially if seizures occur daily. The risk based on early age at seizure onset appeared independent of etiology and persisted within subgroups of patients with focal malformation of cortical development, tumor, or hippocampal sclerosis. Prospective studies will be important to clarify whether early surgical intervention may reduce the risk for subsequent MR in carefully selected infants.

Benign myoclonus of early infancy: an imitator of West's syndrome

Benign myoclonus of early infancy is a rare condition characterized by nonepileptic spasms that may resemble the epileptic spasms seen in West's syndrome. The spells in benign myoclonus of early infancy begin before age 1 year and are self-limited. The electroencephalogram (EEG) is invariably normal, and neurologic development is not affected. West's syndrome is characterized by infantile spasms that appear before 1 year of age, an abnormal EEG with hypsarrhythmia, and a poor prognosis. We describe six infants who presented for evaluation of clusters of head, trunk or extremity spasms, eye blinking, brief jerking of upper extremities or trunk, and head nodding episodes. In most, a presumptive diagnosis of West's syndrome was made prior to the referral. One infant had been placed on valproate. Routine EEG recordings or prolonged video EEG monitoring were normal both during and between episodes. After the negative evaluations, the diagnosis of benign myoclonus of early infancy was made in each infant. Subsequently, no infant was treated with anticonvulsants. Follow-up revealed complete resolution of the episodes in all children within 2 weeks to 8 months of onset. All had normal neurologic development. Based on our cases and review of the literature, the prognosis for this disorder is excellent. Care should be taken to recognize this rare entity and avoid unnecessary and potentially harmful antiepileptic therapy.

Vagus nerve stimulation for children and adolescents with intractable epilepsies

BACKGROUND

Vagus nerve stimulation (VNS) has been shown to be efficacious in the treatment of patients > 12 years of age with refractory partial epilepsies and it is suggested that VNS should be considered as one of the treatment options for these patients.

METHODS

Four patients had partial epilepsies and one had symptomatic generalized epilepsy. After observation of the baseline seizure frequency and the average seizure frequency for 3 months, the VNS system was implanted. Thereafter, seizure frequency, average seizure frequency of each seizure type during the month just before the evaluation, seizure severity, side effects and quality of life were recorded.

RESULTS

In four of five patients, overall seizure frequency was reduced > 50% after VNS treatment. The seizure types that showed a > 50% reduction in frequency were auras, focal clonic, generalized tonic clonic seizures, astatic, versive, hypomotor, generalized tonic and generalized clonic seizures according to Lüders' classification. In two patients, as major convulsive seizures were reduced in number after VNS treatment, dialeptic seizures (non-convulsive seizure with lapse of consciousness) gradually appeared. In one patient without significant seizure reduction, quick recovery from postictal periods after generalized tonic seizure was seen after treatment. In one patient with generalized epilepsy, improvement of cognitive function was reported by his guardians. After VNS, the number of antiepileptic drugs was reduced from three to one in one patient. No significant adverse effects were noted in any patients.

CONCLUSIONS

Our results suggest that VNS is well tolerated in young patients with intractable epilepsies and it may be an important non-pharmacologic treatment option for children with severe epilepsies who cannot tolerate medical therapy and/or are not candidates for epilepsy surgery.

Parent- and patient-validated content for pediatric epilepsy quality-of-life assessment

PURPOSE

The purpose of this study was to assess the parent-and patient-validated content of quality-of-life measurement for use in children with epilepsy.

METHODS

We asked the parents of 80 consecutive children and adolescents with epilepsy to list in order of importance their concerns about living with or caring for their children with epilepsy. Patients were 3 months to 18 years of age (mean, 10 years) and identified at the outpatient clinic or during hospital stay. To minimize investigator bias, parents and children listed their concerns in a private setting without staff involvement.

RESULTS

Twenty-six distinct domains were generated by the parents and children. Concerns listed by more than 20 of parents included medication adverse effects (58), cognitive effects of epilepsy (46), prospects for the future (41), safety (35), independence (31), and brain damage caused by seizures (30). Concerns ranked by parents as most important included safety (18), brain damage from seizures (12), enigma of epilepsy (12), cognitive effects of epilepsy (11), and prospects for the future (10). Concerns listed by more than 20 of children included social problems (35), cognitive effects of epilepsy (29), driving (29), sports (27), medication adverse effects (25), and schooling (21). Concerns ranked by children as most important included issues related to medication adverse effects (13), cognitive effects of epilepsy (10), hatred of epilepsy (8), social embarrassment (6), fear of seizures (6), injury (6), and dislike of hospital visits (6).

CONCLUSION

The effect of epilepsy on health-related quality of life in pediatric patients is defined by a limited number of domains. A 20-item inventory was chosen from the 26 domains generated by the parents and children. Our study provides insight into parents' and children's perception of seizures and the impact of epilepsy on everyday life.

Seizure outcome after surgery for epilepsy due to malformation of cortical development

PURPOSE

To explore seizure outcome after surgery for focal epilepsy due to malformation of cortical development (MCD), with focus on the role of MRI.

METHODS

Thirty-five patients who had surgery for intractable focal epilepsy due to MCD identified by preoperative MRI and confirmed by histopathologic analysis of resected tissue were studied. Patients were aged 3 months to 47 years (median, 14 years) at the time of surgery. Duration of follow-up was 1 to 7.9 (mean, 3.4) years.

RESULTS

At latest follow-up, 17 patients (49%) had Engel Class I outcome with no seizures or auras only; eight patients (23%) had Class II outcome, with rare disabling seizures; seven patients (20%) had worthwhile improvement; and three patients (9%) had no improvement. Seizure-free outcome tended to be more frequent among patients who had complete resection of unilateral MCD (excluding hemimegalencephaly) based on postoperative MRI (7/12; 58%), compared with patients with unilateral MCD who had incomplete resection (3/11; 27%), but the difference was not significant. The frequency of seizure-free outcome did not differ significantly between children (8/14; 57%), adolescents (7/15; 47%) or adults (2/6; 33%); between patients who had daily (12/24; 50%), weekly (4/9; 44%), or monthly (1/2; 50%) seizures preoperatively; between patients who had temporal (2/6; 33%) or extratemporal or multilobar resections (14/28; 50%); or between patients who were (9/16; 56%) or were not (8/19; 42%) studied with subdural electrodes. Results for all analyses were similar when analyzed at latest available follow-up or at 1 year after surgery.

CONCLUSIONS

Surgery can offer seizure-free outcome for approximately one half of carefully selected patients with intractable focal epilepsy due to MCD. Complete resection of the MRI-apparent lesion may improve the likelihood for favorable outcome. MRI evidence of hemimegalencephaly or bilateral MCD suggests a low likelihood for postoperative freedom from seizures.

Multiple sleep latency test and polysomnography in diagnosing Kleine-Levin syndrome and periodic hypersomnia

Kleine-Levin syndrome and periodic hypersomnia are often misdiagnosed initially because there is no objective test for these conditions. To determine the value of the Multiple Sleep Latency Test and polysomnography in this respect, the authors studied four patients with Kleine-Levin syndrome or periodic hypersomnia who had taken the Multiple Sleep Latency Test and undergone polysomnography during the symptomatic episode and/or during the asymptomatic interval. During but not between symptomatic episodes, the Multiple Sleep Latency Test revealed abnormal sleep latencies in all patients, and polysomnography revealed increased rapid eye movement propensity in one patient and a reduction in delta-sleep in two patients. In conclusion, the Multiple Sleep Latency Test and polysomnography are useful in diagnosing Kleine-Levin syndrome and periodic hypersomnia, especially when administered in a standardized fashion during and after the symptomatic period. The authors recommend that polysomnography and the Multiple Sleep Latency Test be performed no earlier than the second night after the onset of a symptomatic episode and the following day to reveal maximal hypersomnolence, and more than 2 weeks after a symptomatic episode to represent the asymptomatic interval.

Epileptogenicity correlated with increased N-methyl-D-aspartate receptor subunit NR2A/B in human focal cortical dysplasia

PURPOSE

Human cortical dysplasia (CD) is a frequent cause of medically intractable focal epilepsy. The neurotransmitter mechanisms of epileptogenicity in these lesions have been attributed to changes in various glutamate receptor subtypes. Increased N-methyl-D-aspartate (NMDA) receptor (NR) 2A/B coassembled with NR1 subunits has been shown in focal epileptic CD. The purpose of this study is to correlate in situ CD epileptogenicity and the expression of various glutamate receptor subtypes.

METHODS

The histopathological, morphological, and immunocytochemical findings in cortical tissue resected from five patients with medically intractable epilepsy and CD were correlated with electroencephalographic data recorded from subdural grids. The NMDA antibodies identified subunits NR1 (splicing variants 1a, 1b, 2a, and 2b) and NR2A/B.

RESULTS

Epileptogenic specimens displayed the following common features: (a) widespread histological abnormalities of horizontal and columnar dyslamination, neurons with inverted polarity, and more extensive dendritic changes; (b) significantly higher NR2A/B immunoreactivity in both the dysplastic somata and all their dendritic processes; and (c) no statistically significant change in NR1 subunit expression but a more pronounced staining of the apical dendrites in highly epileptogenic cortex. These abnormalities were either absent or minimal in resected specimens that did not show evidence of severe in vivo epileptogenicity.

CONCLUSION

These studies provide direct evidence for a major contribution of the NR2A/B subunit in CD-induced epileptogenicity.

Risk factors for unsuccessful testing during the intracarotid amobarbital procedure in preadolescent children

PURPOSE

Identification of risk factors for unsuccessful testing during intracarotid amobarbital procedure (IAP) in preadolescent children.

METHODS

A pediatric IAP protocol was attempted in 42 candidates for epilepsy surgery (5-12 years old; mean, 10 years) based on the ability to pass a practice test. Language dominance was defined by marked asymmetry until first verbal response and paraphasic errors. Intact hemispheric memory was defined by recall of >/=60% of test items. The odds ratios of baseline variables (age at IAP, Full-Scale IQ, side of disease, age at seizure onset, amobarbital dose) were calculated for various IAP outcomes.

RESULTS

IAPs were accomplished in 40 children. Language dominance was established in 25 (62.5%) of 40 patients: all 21 focal resection candidates were left language dominant; four hemispherectomy candidates had intact language after injection of the damaged hemisphere. In 12 (30%) of 40 patients, language testing failed because of agitation or obtundation. Compared with the 21 children with language dominance established by bilateral IAP, these 12 children had lower mean Full-Scale IQ (66.4 vs. 87.9; p = 0.014), and more frequently, the epileptogenic lesion in the left hemisphere (presumed dominant by right-handedness; 78 vs. 33%; p = 0.04). Excluding hemispherectomy candidates (intentionally only one injection), memory testing could not be completed in 13 (36%) of 36 children because of obtundation or agitation. These children were significantly younger than the 23 (64%) of 36 with successful bilateral memory testing (mean age, 107.6 vs. 128.7 months; p = 0. 006). The eight (25%) of 32 children with failing retention scores after ipsilateral injection had lower Full-Scale IQ than did the 24 (75%) patients who passed (mean, 59.6 vs. 81.7 months; p = 0.03).

CONCLUSIONS

The IAP successfully established hemispheric language dominance and memory representation for just under two thirds of the preselected preadolescent children. Risk factors for unsuccessful testing included low Full-Scale IQ (especially <80), young age (especially <10 years), and seizures arising from the left hemisphere presumed dominant by right-handedness.

Lateralizing value of asymmetric tonic limb posturing observed in secondarily generalized tonic-clonic seizures

PURPOSE

A striking asymmetry of limb posture occurs during secondarily generalized tonic-clonic (GTC) seizures wherein one elbow is extended while the other is flexed during the tonic phase of the GTC seizure. We have named this phenomenon asymmetric tonic limb posturing (ATLP) or the "Figure 4 Sign."

METHODS

Fifty-nine secondarily GTC seizures from 31 patients with partial epilepsy who underwent successful epilepsy surgery were analyzed, in addition to another group of 64 GTC and generalized clonic seizures from 26 patients collected prospectively over a 7-month period. Three observers reviewed these seizures blinded to the side of ictal EEG onset and other clinical data.

RESULTS

The extended elbow was contralateral to the side of ictal onset in 35 of 39 patients who had ATLP during their seizures. The kappa index, a measure of interobserver agreement, was calculated, and ATLP was found to have very good agreement between observers.

CONCLUSIONS

In secondarily generalized tonic-clonic seizures, ATLP (Figure 4 Sign) may sometimes be only available lateralizing sign.

Posterior scleral choristoma in the organoid nevus syndrome (linear nevus sebaceus of Jadassohn)

PURPOSE

To highlight the association of posterior osseous and/or cartilaginous ocular choristomas with epibulbar choristomas and the nevus sebaceus of Jadassohn.

DESIGN

Small case series.

PARTICIPANTS

Four patients with the organoid nevus syndrome.

METHODS

Clinical and histopathologic studies in four patients with epibulbar lesions and nevus sebaceus of Jadassohn.

MAIN OUTCOME MEASURES

Ophthalmoscopic findings of peripapillary lesions. Computed tomographic and ultrasonographic characteristic of posterior scleral lesions. Ocular histopathologic findings in one globe from one of the study subjects.

RESULTS

Three patients had the triad of posterior osseous/cartilaginous ocular choristomas, anterior epibulbar choristomas, and nevus sebaceus of Jadassohn and one patient had anterior epibulbar choristomas and posterior osseous/cartilaginous ocular choristomas. Ultrasonography and computed tomography were valuable in detecting scleral ossification or epibulbar cartilage or both. The ophthalmoscopic findings were similar to those of a choroidal osteoma.

CONCLUSIONS

The presence of posterior osseous/cartilaginous ocular choristomas in a patient with epilepsy or epibulbar lesions or both suggests the diagnosis of nevus sebaceus of Jadassohn. Osseous/cartilaginous ocular choristomas should be suspected in patients with nevus sebaceus of Jadassohn and peripapillary hypopigmented fundus lesions.

Symptomatology of epileptic seizures in the first three years of life

PURPOSE

Few data are available concerning symptomatology of epileptic seizures in infants.

METHODS

We reviewed 296 videotaped seizures from 76 patients aged 1-35 months (mean, 15.1 months) who underwent video-EEG monitoring at our institution from 1988 to 1998. Seizure symptomatology was first classified based on observable behavioral and motor manifestations and then correlated with ictal EEG.

RESULTS

Four seizure types accounted for 81% of all seizures seen in this group: epileptic spasms (24%), clonic seizures (20%), tonic seizures (17%), and hypomotor seizures (20%; characterized by arrest or significant decrease of behavioral motor activity with indeterminate level of consciousness). The remaining seizures included small numbers of myoclonic, atonic, and versive seizures. All 12 focal motor seizures and all five versive seizures were associated with focal EEG seizure patterns, seen in the contralateral hemisphere in all but one patient with versive seizures. Generalized motor seizures (clinically generalized at onset) were accompanied either by focal (19 of 51; 37%) or generalized (32 of 51; 63%) EEG seizures. Hypomotor seizures also were associated with focal (14 of 20; 70%) or generalized (six of 20; 30%) EEG seizures. Four patients with generalized epileptic spasms had generalized EEG seizures in the setting of focal epilepsy based on neuroimaging, interictal EEG, and in two cases also on postresection seizure freedom. Seizure types not seen in this age group included auras, seizures with prominent automatisms (except in one case), and classic generalized tonic-clonic seizures.

CONCLUSIONS

The repertoire of seizure manifestation in the first 3 years of life appears to be limited. In infants, focal motor seizures are reliably associated with focal EEG seizures in the contralateral hemisphere, whereas generalized motor and hypomotor clinical seizures may be either focal or generalized on EEG. Epileptic spasms may be seen in focal as well as generalized epilepsies. Video-EEG monitoring and neuroimaging may be critical for clarifying the focal or generalized nature of the epilepsy in infants.

Epilepsy surgery in children with pervasive developmental disorder

Pervasive developmental disorder (PDD) is occasionally associated with medically intractable complex partial seizures. The outcome of PDD was explored in three males and two females who underwent epilepsy surgery at 32 months to 8 years of age (mean = 4 years) after onset of epilepsy at 1 week to 21 months of age (mean = 11 months). Four children had temporal lobe resections (three right, one left; two for focal cortical dysplasia, and two for tumors), and one had a right temporoparieto-occipital resection (for focal cortical dysplasia). Each child underwent repeated evaluations by a pediatric neuropsychologist and psychiatrist. Fourteen to 47 months (mean = 23 months) after operation, one child with persistent seizures had moderate developmental and behavioral improvement, three children (two seizure free, one with rare staring spells) had mild developmental and behavioral improvement, and the remaining child (seizure free) experienced a worsening of her PDD. The four children with mild-to-moderate improvement in postoperative cognitive and behavioral development still demonstrated persistent delay. Cognitive gains were confirmed by neuropsychologic testing in the oldest patient but were not reflected in test results from the three younger children, who had more modest improvement. The child with worsening of her PDD had cognitive and emotional deterioration to babbling, echolalia, aggressiveness, decreased social interaction, and increased mouthing of objects beginning several months postoperatively. These results suggest that families should be counseled that PDD symptoms in children with focal epileptogenic lesions may or may not improve after epilepsy surgery, even if the surgery is successful with respect to seizure control.

Linear epidermal nevus and nevus sebaceus syndromes: a clinicopathologic study of 3 patients

BACKGROUND

Linear epidermal nevus syndrome and linear sebaceus nevus syndrome are rare neurocutaneous syndromes characterized by epidermal nevi, epilepsy, and mental retardation. Pathologic descriptions of the central nervous system findings in such patients are rare.

DESIGN

We examined the clinicopathologic features of 2 patients with linear epidermal nevus syndrome and 1 with nevus sebaceus syndrome who underwent surgical resections for chronic epilepsy in a tertiary referral center with a high volume of epilepsy surgery.

RESULTS

Patients included 3 females, aged 11 months (patient 1), 8 years (patient 2), and 2 1/2 years (patient 3) at the time of surgery. The duration of seizures prior to surgery was 11 months, 6 years, and 28 months, respectively. Two patients had epidermal nevi involving the head region (patients 1 and 3), and 1 had a nevus sebaceus of Jadassohn (patient 2); patient 2 had a choristoma, and patient 3 had a dermoid cyst in the eye region. Patient 1 demonstrated hemimegalencephaly radiographically. Histologic examination of resected cortical tissue in patients 1 and 2 demonstrated severe diffuse cortical dysplasia characterized by a disorganized cortical architectural pattern, a haphazard orientation of cortical neurons, and increased molecular layer neurons. Gyral fusion was seen in patient 1. Pial glioneuronal hamartomas were observed in patient 1. Prominent cortical astrocytosis was seen in patients 1 and 2, and foci of microcalcification were evident in patient 1. Cortical dysplasia was milder in patient 3 and consisted of an increased number of molecular layer neurons. Neuronal heterotopia was observed in all 3 patients.

CONCLUSION

The spectrum of neuronal migration abnormalities in the setting of these syndromes may be variable in terms of its histologic phenotypic manifestations.

Psychiatric features of children and adolescents with pseudoseizures

BACKGROUND

Pseudoseizures may occur as a somatoform disorder in children and adolescents as well as adults. However, few data are available about psychiatric features or outcome in pediatric patients.

PATIENTS AND METHODS

We studied 34 patients (25 girls [74%]) who were evaluated by a child psychiatrist at our institution immediately after diagnosis of pseudoseizures by ictal video electroencephalogram (EEG) at ages 9 to 18 years (mean age, 14 years). Each patient had at least 1 pseudoseizure recorded by video EEG that was judged by the patient and family as typical, characterized by unresponsiveness plus limb twitching or limpness and other features, with EEG showing persistence of normal cortical background rhythms.

RESULTS

In addition to conversion disorder, 11 patients (32%) had mood disorders including major depression, bipolar disorder, or dysthymic disorder, usually with severe psychosocial stressors. Eight children (24%) had separation anxiety and school refusal with moderate psychosocial stressors. Two patients (6%) had brief reactive psychosis or schizophreniform disorder. A few (1-3) patients each had panic disorder, overanxious disorder, adjustment disorder, oppositional/defiant disorder, or impulse control disorder. Four patients (12%) also had personality disorders. Eleven patients (32%) had a history of sexual abuse. This was especially frequent in the subgroup with mood disorders (7 [64%] of 11 patients). Fifteen patients (44%) had severe family stressors including recent parental divorce, parental discord, or death of a close family member. Two patients (6%) had a history of physical abuse. Freedom from pseudoseizures for the preceding 9 to 55 months (mean, 30 months) was achieved for 15 (72%) of the 21 patients who could be reached for telephone follow-up. For 8 (53%) of these 15 patients, the last pseudoseizure was within 1 month of diagnosis by video EEG.

CONCLUSIONS

Major mood disorders and severe environmental stress, especially sexual abuse, are common among children and adolescents with pseudoseizures and should be considered in every case. A subgroup of children with separation anxiety and school refusal had less severe psychiatric problems and moderate psychosocial stressors. Clear diagnosis by video EEG, together with prompt psychiatric evaluation and treatment, may result in freedom from pseudoseizures for most children and adolescents.

A new epileptic seizure classification based exclusively on ictal semiology

Historically, seizure semiology was the main feature in the differential diagnosis of epileptic syndromes. With the development of clinical EEG, the definition of electroclinical complexes became an essential tool to define epileptic syndromes, particularly focal epileptic syndromes. Modern advances in diagnostic technology, particularly in neuroimaging and molecular biology, now permit better definitions of epileptic syndromes. At the same time detailed studies showed that there does not necessarily exist a one-to-one relationship between epileptic seizures or electroclinical complexes and epileptic syndromes. These developments call for the reintroduction of an epileptic seizure classification based exclusively on clinical semiology, similar to the seizure classifications which were used by neurologists before the introduction of the modern diagnostic methods. This classification of epileptic seizures should always be complemented by an epileptic syndrome classification based on all the available clinical information (clinical history, neurological exam, ictal semiology, EEG, anatomical and functional neuroimaging, etc.). Such an approach is more consistent with mainstream clinical neurology and would avoid the current confusion between the classification of epileptic seizures (which in the International Seizure Classification is actually a classification of electroclinical complexes) and the classification of epileptic syndromes.

Hippocampal volumetry in children 6 years or younger: assessment of children with and without complex febrile seizures

PURPOSE

To study the relationship of complex febrile seizures (CFS) in the evolution of mesial temporal sclerosis.

METHODS

We studied five children 22-68 (mean 44) months old with MRI volumetry 2 days-46 months after their first CFS, and compared total hippocampal volumes and right to left hippocampal volume ratios to those of 11 controls, 15-83 (mean 55) months old, who had MRI for complaints which turned out to be neurologically insignificant.

RESULTS

In control children, total hippocampal volumes increased linearly with age, while right to left hippocampal volume ratios tended to decrease with age. In children with CFS total hippocampal volumes tended to be smaller than in controls. Right to left ratios were greater than 1 in all five children with CFS compared to seven of 11 controls. Hippocampal asymmetry was noted in only one child, with the right to left volume ratio exceeding two standard deviations from the control mean. The MRI of this child also demonstrated a subarachnoid cyst in the left frontocentral region, ipsilateral to the smaller hippocampus. Visual inspection of the remaining patients revealed no definite structural cortical abnormalities. None of the children developed subsequent afebrile seizures during the brief follow-up period.

CONCLUSIONS

Hippocampal volumetry in controls revealed a linear increase in total hippocampal volumes and a statistically nonsignificant trend toward reduced right larger than left hippocampal ratios between 17 and 83 months old. The tendency for smaller total hippocampal volumes and larger right to left hippocampal volume ratios in children with CFS compared to controls could suggest a developmental abnormality, injury during CFS, or be age-related. The significant hippocampal asymmetry in a single child with CFS suggests that age may not be a factor in every case. Further studies are needed to collect control data in young children as well as prospectively follow children with CFS with serial imaging to better understand the relationship between CFS and the evolution of hippocampal atrophy.

Staring spells in children: descriptive features distinguishing epileptic and nonepileptic events

OBJECTIVE

To identify questions sensitive and specific for staring spells of epileptic (absence seizures [AS]) or nonepileptic etiology to increase the yield of history taking.

STUDY DESIGN

A questionnaire was completed by parents of 40 children who presented with staring spells. Results from 17 children with AS and 23 with nonepileptic staring (NES) were compared.

RESULTS

Features with moderate sensitivity (43% to 56%) but high specificity (87% to 88%) for NES included preserved responsiveness to touch, lack of interruption of playing, and initial identification by a teacher or health professional. These features were more frequent in NES than in AS (P = .013, .016, .030). Body rocking occurred only in NES, but sensitivity was low (13%). Features with high specificity (91% to 100%) for AS included limb twitches, upward eye movements, and urinary incontinence; but sensitivities were low (13% to 35%).

CONCLUSION

In children with normal interictal electroencephalography findings and without neurologic disease, staring spells are most likely nonepileptic when parents report preserved responsiveness to touch, body rocking, or initial identification by a teacher or health professional without limb twitches, upward eye movements, interruption of play, or urinary incontinence. In these cases a diagnosis of NES may be confidently applied, with confirmation based on long-term follow-up.

Seizure outcome after epilepsy surgery in children and adolescents

Few epilepsy surgery outcome data are available from series of pediatric patients. We studied seizure outcome in 136 pediatric patients who had surgery for intractable epilepsy at The Cleveland Clinic between January 1990 and June 1996, with a postoperative follow-up of 1 to 7.5 years (mean, 3.6 years). Sixty-two children (3 months to 12 years old at time of surgery) were compared with 74 adolescents (13-20 years old). Extratemporal or multilobar resections and hemispherectomies were similarly frequent among children (50%) and adolescents (44%), but these procedures strongly predominated in infancy (90% of patients 0-2 years of age). The remaining patients had temporal resection. Cortical dysplasia and low-grade tumor were the most common causes and hippocampal sclerosis was rare. Seizure-free outcome was achieved for 69% of adolescents, 68% of children, and 60% of the infant subgroup, overall; for 23 (74%) of 31 children and 33 (80%) of 41 adolescents after temporal resection; for 11 (58%) of 19 children and 15 (52%) of 29 adolescents after extratemporal or multilobar resection; and for 8 (67%) of 12 children and 3 (75%) of 4 adolescents after functional hemispherectomy. Seizure-free outcome was more frequent after temporal resection (56 of 72, 78%) than after extratemporal or multilobar resection (26 of 48, 54%; 41 of 48 with a focal lesion on magnetic resonance imaging), and among patients with tumor (36 of 44, 82%) versus cortical dysplasia (16 of 31, 52%). The frequency of seizure-free outcome after epilepsy surgery was similar for infants, children, and adolescents, and comparable with results from adult series. Most patients in each age, surgery type, and causal group were free from seizures after surgery. These results suggest that children should be considered for surgical evaluation at whatever age they manifest with severe, intractable, disabling localization-related epilepsy.

Semiological seizure classification

We propose an epileptic seizure classification based exclusively on ictal semiology. In this semiological seizure classification (SSC), seizures are classified as follows: a. Auras are ictal manifestations having sensory, psychosensory, and experiential symptoms. b. Autonomic seizures are seizures in which the main ictal manifestations are objectively documented autonomic alterations. c. "Dialeptic" seizures have as their main ictal manifestations an alteration of consciousness that is independent of ictal EEG manifestations. The new term "dialeptic" seizure has been coined to differentiate this concept from absence seizures (dialeptic seizures with a generalized ictal EEG) and complex partial seizures (dialeptic seizures with a focal ictal EEG). d. Motor seizures are characterized mainly by motor symptoms and are subclassified as simple or complex. Simple motor seizures are characterized by simple, unnatural movements that can be elicited by electrical stimulation of the primary and supplementary motor area (myoclonic, tonic, clonic and tonic-clonic, versive). Complex motor seizures are characterized by complex motor movements that resemble natural movements but that occur in an inappropriate setting ("automatisms"). e. Special seizures include seizures characterized by "negative" features (atonic, astatic, hypomotor, akinetic, and aphasic seizures). The SSC identifies in detail the somatotopic distribution of the ictal semiology as well as the seizure evolution. The advantages of a pure SSC, as opposed to the current classification of the International League Against Epilepsy (ILAE), which is actually a classification of electroclinical syndromes, are discussed.

Neuropsychological effect of temporal lobe resection in preadolescent children with epilepsy

PURPOSE

Numerous studies have demonstrated changes in cognitive, memory, and language functioning in adults and adolescents after temporal lobectomy, yet little information is available regarding neuropsychological outcome in preadolescent children.

METHODS

We studied pre- and postoperative neuropsychological test results from 14 children who underwent temporal lobe resection for intractable epilepsy at age 7-12 years (mean 9.4 years).

RESULTS

Thirteen patients (93%) had no seizures or less than one seizure a year at follow-up 23-48 months (mean 34 months) after operation. Postoperative neuropsychological testing was performed 6-9 months (mean 7 months) after surgery in 13 patients and 36 months after the first operation in 1 patient who underwent two-stage resection of a tumor. Verbal, Performance, and Full Scale IQ were initially in the low-average range, with no significant change across the pre- and postoperative evaluations. Immediate verbal memory performance decreased significantly in children who initially performed above the median preoperatively and tended to decrease in children who had left rather than right temporal lobe resection. Significant postoperative decreases in delayed memory scores were independent of preoperative ability or side of resection.

CONCLUSIONS

Our small study suggests vulnerability to postoperative decline in immediate verbal memory scores in preadolescent children who have higher baseline immediate memory function or undergo left rather than right temporal lobe resection, similar to that observed in adolescents in adults. The entire group exhibited a statistically significant decrease in delayed verbal memory. Study of larger series of patients will be important to clarify further the short- and long-term risks and benefits of temporal lobe resection in childhood.

Lateral frontal lobe seizures

On the basis of cytoarchitectural and functional studies, the frontal lobe can be subdivided into the primary motor cortex, premotor cortex, prefrontal cortex, and the limbic and paralimbic cortices. However, we are still a long way from clearly identifying individual frontal lobe epilepsies. Instead, we are limited to a discussion of frontal lobe seizures arising from various regions of the frontal lobe. Supplementary motor area epilepsy and perirolandic epilepsy have been quite well defined, in contrast to syndromes involving other regions of the frontal lobe. Recent technological advances in neuroimaging, electroencephalography, magnetoencephalography and detailed videotape analysis of seizure semiology may enable us to delineate these frontal lobe syndromes with better accuracy, thereby improving outcome after epilepsy surgery.

Ganglioglioma and intractable epilepsy: clinical and neurophysiologic features and predictors of outcome after surgery

PURPOSE

To review the clinical, neurophysiologic, and radiological data of patients with ganglioglioma who had undergone evaluation and surgery in our Epilepsy Program.

METHODS

The medical and neurophysiologic records of 38 patients with intractable epilepsy and ganglioglioma were reviewed. Data underwent statistical analysis.

RESULTS

There were 28 temporal and 10 extratemporal resections, with a mean age at seizure onset of 10.5 years and mean age at surgery of 22 years. Five tumor resections performed earlier were recorded. Twenty-nine patients had auras and 20 had secondarily generalized seizures. All 28 patients with temporal tumor had complex partial seizures. Preoperative MRI demonstrated the tumor in 36 of 36 patients: 17 of 29 demonstrated gadolinium enhancement, and 17 of 36 had mass effect. Scalp interictal sharp waves were present in 32 patients, and in 15 they were multiregional. In two patients, scalp EEG seizure onset was from the hemisphere contralateral to the tumor. Postoperatively, 79% of patients (30 of 38) were seizure-free (Engel's class I) at 6 months, 72% at 1 year (26 of 36), and 63% at 2 years (20 of 32). Excellent outcome was associated with a lower age at operation (p = 0.008), shorter duration of epilepsy (p = <0.01), absence of generalized seizures (p = <0.01), and no epileptiform discharges on a postoperative EEG (p = 0.01).

CONCLUSIONS

Good surgical outcome is expected in patients with ganglioglioma despite years of medically resistant seizures. Good outcome may be achieved despite EEG findings that may conflict with tumor location, and is more likely when surgery is performed relatively soon after epilepsy onset.

Epilepsy surgery outcome: comprehensive assessment in children

The effect of extratemporal and temporal lobe cortical resection on children with intractable epilepsy is not well understood. We evaluated a comprehensive array of outcome variables in 33 consecutive children who received epilepsy surgery at 12 years of age or younger. Twenty-two (67%) children were seizure-free, three (9%) had a greater than 90% reduction in seizures, and four had no improvement. Antiepileptic drugs (AEDs) were not required in 10 (30%) children and were reduced in number in another 10. Six (29%) of 21 tested children had an improvement of greater than 10 points in Verbal or Performance IQ after surgery, while one (4%) had a decrease greater than 10 points in Verbal IQ. One mild hemiparesis and one inferior quadrantanopsia occurred; both were anticipated. We used the Child Health Questionnaire (CHQ), a valid and reliable instrument for children, to assess health-related quality of life (HRQOL). Six of 12 subscale scores of the CHQ were significantly lower in the surgical group compared with 410 age-matched control subjects. Parents were satisfied with surgical results in 28 (85%) cases. Pathologic tissue diagnosis and site of resection were not associated significantly with any outcome measure. We conclude that surgery eliminates seizures and reduces AED requirements in most children with intractable epilepsy selected by currently available methods. Further investigation is needed to establish the nature and significance of inferior scores in the surgical group in the HRQOL domains of physical function, general health, and self-esteem.