Symptomatology of infantile spasms.

Epileptic spasms in West syndrome consist of a brief phasic contraction followed by a gradually relaxing tonic component, associated with typical ictal electroencephalographic (EEG) patterns. Three different EEG patterns are associated with a clinical spasm: fast wave bursts, high voltage slow waves (HVS), and desynchronization, occurring in this order. HVS are consistently seen and correspond to a clinical spasm, but usually preceded by fast wave bursts, which may be associated with an inhibition of muscle activity. Epileptic spasms can be classified into: symmetric spasms, asymmetric/asynchronous spasms, focal spasms, spasms with partial seizures, subtle spasms, spasms preceded by brief atonia, or subclinical spasms. Although clinical spasms are usually symmetric, ictal fast waves are always localized, and the following slow waves are not bilaterally synchronous and generalized, suggesting a focal cortical origin of spasms.     

A triad of infantile spasms,nystagmus and a focal tonic seizure

Epileptic spasms represent a subcategory of motor seizures that have been extensively documented and recently re‐classified by the International League Against Epilepsy as either generalized, focal or of unknown onset. Atypical characteristics continue to be reported in case studies, emphasizing the divergent morphological traits and putting into question the underlying aetiopathophysiology. Here, we report the findings of an infant with a triad of clinical manifestations during a single ictal event, comprising a cluster of epileptic spasms, vertical binocular nystagmus, and a focal tonic seizure. A video recording is presented that enabled clinical data to be correlated with EEG modifications. To date, a focal lesion has not been identified on brain imaging. The co‐occurrence of these ictal paroxysms provides insight into the anatomical localization of seizure onset and complex epileptic networks involved, and challenges the pathophysiological hypothesis for epileptic spasms, implicating cortical‐subcortical dysfunction and the implication of structures deep within the sulcus. Furthermore, the focal components both clinically and electrographically implicate involvement of the frontal eye field in the generation of vertical ictal nystagmus. [Published with video sequence on www.epilepticdisorders.com ].     

Diurnal and sleep/wake patterns of epileptic spasms in different age groups

Purpose: Epileptic spasms are seizures that occur predominantly in children and are characterized by clusters of brief axial movements. Epileptic spasms may occur in the context of a variety of syndromes. Previous research has found that epileptic spasms occur in a sleep/wake and diurnal rhythm. The purpose of this study was to identify these patterns in different age groups. Methods: Charts of 2,021 patients with epilepsy undergoing video–electroencephalography (EEG) monitoring over a 10‐year period were reviewed for presence of epileptic spasms and analyzed for their occurrence during the day (6 a.m. to 6 p.m.) or night, out of wake or sleep, and in 3‐h time‐blocks throughout the day. Exact epileptic spasm time, EEG localization, and the presence or absence of magnetic resonance imaging lesion were also recorded. Patients were separated into two age groups: A ages 3 and under, and over age 3. Statistical analysis of seizure occurrence in time bins was carried out using binomial calculations. p‐Values <0.05 were taken as significant. Using exact seizure times, a generalized linear mixed model of the Poisson‐family with a square root link function was used to calculate mean seizure times. Age, as a binary variable, and time, as a categorical variable, was treated as fixed effect predictors, and individual effects were modeled as random effects. For comparison between the two age groups, over age 3 and under age 3, seizure times were transformed into circular variables. A circular analysis of variance test was used to assess for the difference in mean seizure time, assuming a von Mises distribution of the circle. Key Findings: We analyzed 219 clusters of epileptic spasms in 51 patients (15 girls; mean age 2.15 ± 2.22 years). Forty‐two patients younger than 3 years of age had 163 seizures and nine patients older than 3 years had 56 seizures. Epileptic spasms occurred predominantly during wakefulness (p < 0.001) and during daytime (p < 0.001). Epileptic spasms occurred most frequently between 9 a.m. and noon (p < 0.05) and between 3 p.m. and 6 p.m. (p < 0.001). Patients without magnetic resonance imaging lesions had most seizures between 9 a.m. and noon (p < 0.01) and 3 p.m. and 6 p.m. (p < 0.001). Thirty‐seven patients had 157 epileptic spasms (71.2%) with generalized EEG patterns and 14 patients had 62 epileptic spasms (28.8%) with focal EEG patterns. Generalized EEG seizures occurred more frequently than focal EEG seizures (p < 0.001). Following age stratification, patients younger than 3 years had most epileptic spasms between 9 a.m. and noon (p < 0.05) and 3 p.m. and –6 p.m. (p < 0.01) and patients older than 3 years had most epileptic spasms between 6 a.m. and –9 a.m. (p < 0.05) and a second peak between 3 p.m. and 6 p.m., although the difference was not statistically significant due to insufficient numbers. Using continuous time analysis, the mean seizure time in the under age 3 and the over age 3 groups was 2:24 p.m. and 11:40 a.m. Using a circular analysis of variance test, the difference between mean seizure times in these groups was found to be statistically significant (p = 0.038). Significance: Epileptic spasms occur more frequently in the waking state and daytime. Younger patients have epileptic spasms mostly between 9 a.m. and noon and 3 p.m. and –6 p.m., and older patients have epileptic spasms mostly between 6 a.m. and 9 a.m. These findings emphasize age‐related changes in epileptic spasm pathophysiology or potentially evolution of disease with age.     

Cryptogenic Late‐onset Epileptic Spasms: An Overlooked Syndrome of Early Childhood?

PURPOSE: Few reports detailing late-onset epileptic spasms have been published. To determine whether this condition merely represents a late variant of classic West syndrome or exhibits specific features distinct from the latter and related to a later stage of brain maturation, we analyzed the whole population with this specific seizure type, excluding symptomatic cases to avoid the effect of brain lesion. METHODS: We reviewed the files of the 56 children evaluated for epileptic spasms in clusters having begun at age 12 months or later and analyzed clinical and video-EEG data of the 22 patients (4-17 years; mean, 8.5 years) without obvious cause. RESULTS: Interictal EEG did not show classic hypsarrhythmia. A temporal or temporofrontal slow wave and/or spike focus could be identified in all cases. Twelve children showed spasms with a tonic component. Ictal EEG revealed generalized high-voltage slow wave followed by diffuse voltage attenuation with superimposed fast activity. All children also exhibited other types of recorded seizures consisting of bursts of spike-waves with temporofrontal predominance, reminiscent of "atypical absences." In contrast with the occurrence of tonic components within a cluster of spasms, no tonic seizure stricto sensu was recorded or reported by the caregivers. In 10 children, treatment (two vigabatrin, seven hydrocortisone, one adrenocorticotropic hormone) achieved complete cessation of seizures and disappearance of focal EEG anomalies, but spasms persisted in 12 children. CONCLUSIONS: The cryptogenic group in our series without recognized cause and temporal or temporofrontal EEG anomalies seems to represent a type of epileptic encephalopathy intermediary between West and Lennox-Gastaut syndromes, in terms of seizure types and interictal EEG, and could correspond to dysfunction of the maturation process of the temporal lobe, possibly due to an undisclosed lesion.     

Infantile epileptic encephalopathy with late‐onset spasms: Report of 19 patients

Purpose: Late‐onset spasms (LOS) are epileptic spasms starting after the first year of life. Our aim was to assess the electroclinical features and the follow‐up of the patients with this particular type of epileptic seizure. Methods: We retrospectively included all patients with LOS confirmed by electroencephalography between 1989 and 2008. Clinical and electroencephalographic findings at diagnosis and during follow‐up were collected. The Vineland scale was used to evaluate the neuropsychological outcome. Results: We report 19 patients with LOS of 240 patients with recorded epileptic spasms. Eighteen patients had an epileptic encephalopathy with late‐onset spasms. The ictal electroencephalography (EEG) showed a focal or generalized discharge of triphasic slow‐waves, slow‐spikes, or slow spikes‐waves with fast activities. The interictal EEG usually showed focal or generalized slow‐waves or slow spikes‐waves without hypsarhythmia. LOS were controlled in only six patients. Three developed typical Lennox‐Gastaut syndrome and 10 had a severe epileptic encephalopathy. Neuropsychological outcome was evaluated in 15 patients with the Vineland scale. Cognitive functions were normal in only one patient, whereas severe cognitive delay was observed in 12 of 15. Conclusion: Epileptic spasms may appear after the age of one. They are more frequently observed in patients with epileptic encephalopathy. In few patients this type of seizure was observed before the patients fulfill Lennox‐Gastaut syndrome criteria. In one patient, we diagnosed a focal epilepsy with seizures occurring in cluster. When LOS are related to an epileptic encephalopathy, this epileptic syndrome seems to be linked to refractory epilepsy and severe cognitive outcome unrelated to the etiology.     

Epileptic spasms: a previously unreported manifestation of WDR45 gene mutation

WDR45 mutations cause neurodegeneration with brain iron accumulation, usually presenting with early childhood developmental delay and followed by early adulthood extrapyramidal symptoms. Although various seizure types may occur, epileptic spasms have not been reported for this disease. Our patient initially developed a prolonged, focal‐onset seizure at three months of age and was subsequently noted to have psychomotor delay. At 11 months of age, she developed epileptic spasms. Her EEG showed hypsarrhythmia. An extensive neurogenetic workup and brain MRI, revealing normal data, ruled out other detectable causes of epileptic spasms. Whole‐exome sequencing revealed a de novo, heterozygous deleterious mutation c.400C>T (p.R13X) in WDR45, previously reported to be disease‐causing and associated with early childhood global developmental delay and seizures other than epileptic spasms. We conclude that WDR45 mutations should be considered as a possible aetiology in infants with early‐onset focal seizures and/or in otherwise undiagnosed cases of epileptic spasms.     

Clinical and electrographic features of epileptic spasms persisting beyond the second year of life

PURPOSE: Few reports detailing the electroclinical features of epileptic spasms persisting beyond infancy have been published. We sought to characterize this unique population further. METHODS: We retrospectively reviewed the clinical and video-EEG data on 26 patients (4-17 years; mean, 93 months) with a confirmed diagnosis of epileptic spasms and who were evaluated at our tertiary referral center between 1993 and 2000. RESULTS: In half of our cases, epileptic spasms were associated with disorders of neuronal migration, severe perinatal asphyxia, and genetic anomalies. Interictal EEGs showed generalized slowing in the majority of patients, and a slow-wave transient followed by an attenuation of the background amplitude was the most common ictal EEG pattern associated with an epileptic spasm (19 cases). Other seizure types (number of cases in parentheses) included tonic seizures with or without a preceding spasm (13), partial seizures (11), myoclonic seizures (11), generalized tonic-clonic seizures (six), atypical absence seizures (two), and atonic seizures (one). Cases with a more organized EEG background (especially with frequencies > or =7 Hz) were more likely to have better cognition. Continued disorganization of the EEG background and persistence of hypsarrhythmia were associated with poor developmental outcome. CONCLUSIONS: Patients with epileptic spasms persisting beyond age 2 years constitute a truly refractory population, one that should be better recognized by clinicians. Interestingly, although many therapies resulted in a >50% reduction in seizures, neither neurocognitive function nor quality of life was substantially improved with intervention. The interictal EEG background is the most helpful in predicting neurologic outcome.     

Surgical outcomes for intractable epilepsy in children with epileptic spasms

Epileptic spasms, or seizures marked by flexor, extensor, or flexor-extensor spasms, are not always responsive to medical management. The purpose of our study was to evaluate the outcome of epilepsy surgery in children with medically intractable epileptic spasms. We identified 11 children with epileptic spasms who underwent lesionectomy (36%), lobectomy (27%), multi-lobectomy (9%), hemispherectomy (18%), or corpus callosotomy (9%). At the time of surgery, 6 children had developed other concurrent seizure type(s), including simple partial (9%), complex partial (27%), partial undifferentiated (9%), primary generalized tonic clonic (9%), tonic (9%), atonic (27%), and myoclonic (9%) seizures. Six children (55%) were seizure free at last follow-up from initial surgery. Predictors of favorable outcome included lack of focal slowing and the presence of less than 2 interictal epileptiform abnormalities on postoperative electroencephalogram (P = .035 and .035, respectively). Favorable outcome was significantly associated with parent/caregiver report of improved postoperative developmental outcomes (P = .026).     

Atypical presentation in Rasmussen encephalitis: delayed late-onset periodic epileptic spasms

A five-and-a-half-year-old girl started experiencing progressive left hemiparesis at age two and a half years. At age five years and four months she started presenting clusters of asymmetric periodic epileptic spasms with no hypsarrhythmia. The ictal EEG showed periodic, constant and stereotyped complexes. Serial brain imaging revealed progressive atrophy of the right hemisphere with increased T2 signal on MRI. She underwent a right hemispherotomy, and histological examination showed signs of inflammation and features of focal cortical dysplasia (FCD). She has been seizure-free for 16 months. This case is unique in the following aspects: the presence of typical Rasmussen encephalitis features of progressive unilateral brain involvement without seizures, a delay of almost three years prior to seizure onset; an atypical seizure type presentation with periodic epileptic spasms and the presence of FCD associated with inflammatory changes. [Published with video sequences].     

Instruction manual for the ILAE 2017 operational classification of seizure types

This companion paper to the introduction of the International League Against Epilepsy (ILAE) 2017 classification of seizure types provides guidance on how to employ the classification. Illustration of the classification is enacted by tables, a glossary of relevant terms, mapping of old to new terms, suggested abbreviations, and examples. Basic and extended versions of the classification are available, depending on the desired degree of detail. Key signs and symptoms of seizures (semiology) are used as a basis for categories of seizures that are focal or generalized from onset or with unknown onset. Any focal seizure can further be optionally characterized by whether awareness is retained or impaired. Impaired awareness during any segment of the seizure renders it a focal impaired awareness seizure. Focal seizures are further optionally characterized by motor onset signs and symptoms: atonic, automatisms, clonic, epileptic spasms, or hyperkinetic, myoclonic, or tonic activity. Nonmotor‐onset seizures can manifest as autonomic, behavior arrest, cognitive, emotional, or sensory dysfunction. The earliest prominent manifestation defines the seizure type, which might then progress to other signs and symptoms. Focal seizures can become bilateral tonic–clonic. Generalized seizures engage bilateral networks from onset. Generalized motor seizure characteristics comprise atonic, clonic, epileptic spasms, myoclonic, myoclonic–atonic, myoclonic–tonic–clonic, tonic, or tonic–clonic. Nonmotor (absence) seizures are typical or atypical, or seizures that present prominent myoclonic activity or eyelid myoclonia. Seizures of unknown onset may have features that can still be classified as motor, nonmotor, tonic–clonic, epileptic spasms, or behavior arrest. This “users’ manual” for the ILAE 2017 seizure classification will assist the adoption of the new system.     

Focal cortical high-frequency oscillations trigger epileptic spasms: Confirmation by digital video subdural EEG

OBJECTIVE: To localize high-frequency oscillations (HFOs) on the cortex during epileptic spasms using video subdural EEG and Multiple Band Frequency Analysis (MBFA). METHODS: Using video subdural EEG sampled at 1 kHz, we studied a 14-year-old boy with asymmetric epileptic spasms of possible left frontal origin. We identified HFOs, then analyzed and localized their distributions by MBFA. We correlated HFO distribution to clinical spasm intensity. RESULTS: Ictal subdural EEG recorded HFOs at 60-150 Hz lasting 0.3-4 s. MBFA showed extensive but noncontiguous distribution of HFOs predominantly over the left frontal and temporal regions. HFOs began and became quasiperiodic before manifestation of clinical spasms. As clinical spasms intensified, HFOs persisted in regions where they initiated subclinically but were of higher frequency and greater power than HFOs in other regions. We performed cortical resections over the left frontal and temporal regions with predominant HFOs. Six months after surgery, the patient remained seizure free. CONCLUSIONS: HFOs were present over the ictal onset zone during epileptic spasms. Periodic spasms in this patient had the characteristics of partial seizures. SIGNIFICANCE: We show that HFOs occurred over the cerebral cortex during epileptic spasms, and we suggest that these focal cortical HFOs triggered the spasms.     

Epileptic spasms without hypsarrhythmia showing astatic seizures in clusters

It is difficult to differentiate astatic seizures among atonic, myoclonic and tonic seizures without the help of ictal polygraphic recordings. We described a girl with epilepsy presenting periodic astasia caused by epileptic spasms. Her seizures had occurred in clusters since 1-year and 7-month of age. Her interictal electroencephalogram (EEG) showed intermittent diffuse (poly) spike (s) and wave discharges, without a trace of hypsarrhythmia. She had a diagnosis of epilepsy with myoclonic-astatic seizures at a previous hospital, and her seizures had been resistant to multiple antiepileptic agents. After she was referred to our hospital, the ictal video-EEG recordings were made before and after ACTH administration, which revealed that her astatic seizures were epileptic spasms with presumed cortical origin. We should carefully evaluate the astatic seizures during early childhood which may be an atypical presentation of epileptic spasms.     

Neurophysiology of spasms.

Spasms are a form of epileptic seizure typical of infancy. From a clinical point of view, the child presents a flexor-extensor movement involving the trunk and limbs and lasting about 1s. Although asymmetry can be present, the seizure involves both sides of the body.The ictal discharge most frequently associated with spasms in West syndrome (WS) is a diffuse triphasic slow high-amplitude wave and less frequently a low-amplitude brief rapid rhythm. The origin of the spasm in WS and classification as either partial or generalized seizure are the subject of much discussion.Factors supporting partial origin include: interictal electroencephalography (EEG) characterized by multifocal anomalies; high incidence of focal cortical lesions and remission of spasms following surgical removal of focal lesions. Factors supporting generalized origin are: clinical involvement of the entire body; mostly generalized ictal EEG pattern; existence of idiopathic cases and possibility of spasms immediately following a partial seizure like a particular form of secondary generalization. In our opinion, the categories of 'partial' and 'generalized' seizures are not applicable to spasms in WS. Sometimes the spasms in WS can be observed together with other types of partial or generalized seizures.Polygraphic recordings have demonstrated that despite being clinically similar, each spasm is different from the other because of a variable sequence in muscular contraction.These data support the peculiar nature of the spasm in WS that could be a subcortical phenomenon that requires a cortical trigger.     

Choroid plexus papilloma and infantile spasms.

A 7-month-old infant had the infantile spasm syndrome, consisting of flexor and extensor spasms, developmental delay, and hypsarrhythmia. Corticotropin produced delay, and hypsarrhythmia. Corticotropin produced improvement in the clinical symptoms and reverted the generalized electroencephalographic abnormalities to more focal ones. Removal of a choroid plexus papilloma of the left lateral ventricle was followed by clinical recovery. One year later the child was normal developmentally and neurologically and was seizure free on anticonvulsant therapy.     

The origin of hypsarrhythmia and tonic spasms in West syndrome: evidence from a case of porencephaly and hydrocephalus with focal hypsarrhythmia

We report on a 3-year-old girl with West syndrome and with focal hypsarrhythmia. The left hemisphere of the patient was virtually completely defective and continuous hypsarrhythmia was only seen in the residual right frontal cortex, where an interictal single photon emission computed tomography (SPECT) showed hyperperfusion. Despite a focal epileptic pattern, the tonic spasms were quite symmetrical. In our patient, spasms might not require the sensorimotor cortex, but the brainstem containing the descending pathways that control spinal reflexes and other infratentorial structures seem to be essential for the occurrence of spasms. This is in accordance with the result of an ictal SPECT that showed hyperperfusion of the brainstem and cerebellum. These findings suggest that hypsarrhythmia originates from cortical lesions, while subcortical structures may be primarily responsible for the tonic spasms in this patient.     

The Axial Spasm—The Predominant Type of Drop Seizure in Patients with Secondary Generalized Epilepsy

In 45 patients suffering from secondary generalized epilepsy, we have recorded 239 drop seizures both by radio-telemetered EEG/split-screen video taping and polygraphically. Twenty of these patients had pure tonic drop seizures. Nine patients each had myoclonic-atonic or pure atonic seizures, whereas seven had slow falls that occurred during gradually developing tonic or akinetic seizures. We term the pure tonic drop seizure "axial spasm." It consists of a uniform pattern of movement lasting from 0.5 to 0.8 s and leading to a specific bearing characterized by a moderate flexion of the hips, the upper trunk, and the head. The arms are almost always involved being abducted, elevated and in a semiflexed position. A fall is provoked by the rapidity and violence of the flexion in the hips. The spasms can occur independently (pure axial spasm) or in connection with other seizure manifestations (combined axial spasm). In pure spasms, no disturbance of consciousness and no significant EEG changes--apart from a slight attentuation--are seen. In the combined axial spasms, distinct epileptic phenomena, in close connection with the axial spasms, can be observed, appearing either in the postspasm phase or in both the pre- and the afterphases. The prephase consists always of an absence and spike-and-wave activity. The onset of the spasm coincides with the last generalized spike, which is followed by a biphasic high-voltage slow wave. In the afterphases, various seizure patterns can be seen; quite characteristic are arrest states during which the patients are completely immobile and take up a postural-like or athetoid position. Almost as frequent are absences or absence-like states and tonic seizures. The afterphase can be compounded by two or three of these seizure patterns, the most common sequence of events in these cases being tonic--arrest state--absence. From the clinical and neurophysiological points of view, axial spasms can be regarded as a more mature form of infantile spasms. Clinical and experimental findings suppose a brainstem origin.     

Statistical mapping of ictal high-frequency oscillations in epileptic spasms

Purpose: We assessed 636 epileptic spasms seen in 11 children (median 44 spasms per child) and determined the spatial and temporal characteristics of ictal high‐frequency oscillations (HFOs) in relation to the onset of spasms. Methods: Electrocorticography (ECoG) signals were sampled from 104–148 cortical sites per child, and the dynamic changes of ictal HFOs were animated on each individual’s three‐dimensional (3D) magnetic resonance (MR) image surface. Key Findings: Visual assessment of ictal ECoG recordings revealed that each spasm event was characterized by augmentation of HFOs. Time‐frequency analysis demonstrated that ictal augmentation of HFOs at 80–200 Hz was most prominent and generally preceded those at 210–300 Hz and at 70 Hz and slower. Recruitment of HFOs in the rolandic cortex preceded the clinical onset objectively visualized as electromyographic deflection. The presence or absence of ictal motor symptoms was related more to the amplitude of HFOs in the Rolandic cortex than in the seizure‐onset zone. In a substantial proportion of epileptic spasms, seizure termination began at the seizure‐onset zone and propagated to the surrounding areas; we referred to this observation as the “ictal doughnut phenomenon.” Univariate analysis suggested that complete resection of the sites showing the earliest augmentation of ictal HFOs was associated with a good surgical outcome. Significance: Recruitment of HFOs at 80–200 Hz in the rolandic area may play a role in determining seizure semiology in epileptic spasms. Our study using macroelectrodes demonstrated that ictal HFOs at 80–200 Hz preceded those at 210–300 Hz.     

A detailed analysis of frontal lobe seizure semiology in children younger than 7 years

PURPOSE: We sought to analyze semiology of seizure onset and evolution in young children with frontal lobe epilepsy (FLE), compare this with adult reports, and assess age-related differences. METHODS: We analyzed 111 videotaped seizures from 14 patients with FLE based on focal cortical dysplasia aged 3-81 months (mean, 30 months). Ictal events were categorized into behavioral, consciousness, autonomic, and sensory features, as well as motor patterns, which included tonic, clonic, epileptic spasm, and myoclonic seizure components. We developed a time-scaled datasheet to record each epileptic event as onset, very early, early, or late manifestation. RESULTS: Patients had a high seizure frequency with up to 40 attacks/day; half of them showed a cluster tendency. Forty-seven percent of the seizures started in sleep. Mean duration of seizures was short (29 s). Most common seizure components were motor manifestations, mostly tonic-clonic seizures, and epileptic spasms. Behavioral change was frequent, and hypermotor seizures were not seen. In five patients, the motor features were contralateral to the epileptic focus, including two children with asymmetric epileptic spasms. Secondarily generalized tonic-clonic seizures (SGTCSs) were not recorded, but had been reported in the history of two patients. Complex motor automatisms were not seen, whereas oral automatism appeared in three children. CONCLUSIONS: Motor features are common in young children with FLE, as reported in adults. The characteristics, however, differ. Epileptic spasms and subtle behavioral change were frequent. Hypermotor seizures and complex motor automatisms were not seen, and SGTCSs were unusual. Our results suggest that FLE in young children shows age-related features differing from those of adults.     

Epileptic spasms preceded by partial seizures with a close temporal association

PURPOSE: To investigate the distinctive features of patients with West syndrome who had partial seizures followed by epileptic spasms (PS-ES). METHODS: We examined 45 patients with West syndrome whose epileptic spasms were recorded with simultaneous video-electroencephalography (EEG) monitoring between 1982 and 1996. We investigated the patients who had PS-ES and compared the PS-ES patients with the 37 patients without PS-ES. RESULTS: Of the 45 patients who had epileptic spasms in clusters (ES) and hypsarrhythmia on the interictal EEG, eight (17%) had ES preceded by partial seizures (PS) with a close temporal association. Seven of these eight were female patients. The underlying disorders were tuberous sclerosis (one patient), Aicardi syndrome (one), nonketotic hyperglycinemia (one), and focal cortical dysplasia (one). The etiology was unknown in the remaining four patients, but was suspected to be of prenatal origin in three. Three types of seizure sequence were identified: PS followed several seconds later by ES (two patients), alternating PS and ES starting with PS (three), and PS gradually replaced by ES with overlapping of the two (three). PS-ES disappeared or was replaced by other types of seizures in 1-34 months. Six patients could not walk, and all patients could not speak any sentences at age 3 years. CONCLUSIONS: Compared with patients without PS-ES, those with PS-ES more often had organic brain lesions of prenatal origin, other types of seizures before the onset of ES, asymmetric hypsarrhythmia on the EEG, and poor psychomotor outcome.