Childhood epilepsy with occipital paroxysms: clinical variants in 134 patients

PURPOSE: In its recent proposal, the Commission on Classification and Terminology of the International League Against Epilepsy classified childhood epilepsy with occipital paroxysms (CEOP) into two syndromes with different predominant seizure types: early onset (Panayiotopoulos type) with eye deviation and ictal vomiting and late onset (Gastaut type) with initial ictal visual symptoms. We documented the clinical features of a large group of patients with CEOP to confirm whether the classification is justified. METHODS: A file review of all patients with partial-onset seizure and interictal occipital spikes referred to our pediatric seizure unit between January 1975 and May 1997 yielded 134 who met the criteria for CEOP. Data were collected with a specially developed protocol and classified according to the two International League Against Epilepsy systems: (a) seizure classification, to test age-specific differences associated with the predominant seizure type, and (b) syndrome classification, to determine whether the clusters of signs and symptoms are sufficiently delineated. RESULTS: Three groups were defined according to the predominant ictal manifestations. Group 1 (visual) consisted of 24 patients (17.9%) with ictal visual symptoms; 19 (14%) of these patients also had overlapping adversive manifestations, either as a separate seizure or as part of the same event (median age at first and last seizure, 7 years 11 months and 10 years). Group 2 (adversive) consisted of 72 patients (53.7%) with tonic eye deviation (median age at first and last seizure, 5 years 2 months and 7 years 2 months). Group 3 (nonvisual, nonadversive) consisted of 38 patients (28.4%) with various seizure spread patterns (median age at first and last seizure, 6 and 7 years 2 months). Two syndromes were identified. The Gastaut type included all 24 patients in the visual group (group 1); seizures were brief and frequent and were diurnal in 83%. The Panayiotopoulos type included all 72 patients in group 2; ictal eye deviation occurred in 100% of the patients and ictal vomiting in 44%; prolonged seizures were observed in 35% and were more frequent in patients who had ictal vomiting than in those who did not (46.8% versus 25%, respectively; p < 0.027). Seizures were infrequent; 24% of patients had a single seizure and 58% had nocturnal seizures. Onset was earlier than for the Gastaut type (p < 0.002). The 38 patients with nonoccipital manifestations did not satisfy the criteria for the complete form of either syndrome. CONCLUSIONS: The most common type of CEOP, the Panayiotopoulos type, is characterized by a cluster of signs and symptoms sufficiently delineated to justify their separate classification from Gastaut-type CEOP, despite the absence of ictal vomiting in more than 50% of the patients.     

A study of 43 patients with panayiotopoulos syndrome,a common and benign childhood seizure susceptibility

PURPOSE: To determine prevalence, clinical, EEG features, and prognosis of Panayiotopoulos syndrome and to examine the proposition that clinical manifestations are more important than EEG findings. METHODS: We analyzed retrospectively the clinical and EEG records of 1,340 children with one or more focal seizures seen in the last 18 years, supplemented with a prospective study from 1998. Panayiotopoulos syndrome was defined by clinical criteria, mainly ictal emesis, irrespective of EEG findings. RESULTS: We analyzed 43 of 90 patients with Panayiotopoulos syndrome who were seizure free >2 years. Girls predominated. Mean age at first seizure was 5 years. Seizures consisted mainly of autonomic manifestations; ictal emesis was often the first symptom, culminating in vomiting in 86%. Of nonautonomic manifestations, lateral eye deviation was the most common; visual symptoms were exceptional. Impairment of consciousness ensued in all seizures, half of which ended with hemi or generalized convulsions. Nearly 46.5% of cases had at least one seizure >30 min, constituting autonomic status epilepticus. Seizures during sleep (84%) were more common than those in wakefulness. EEG showed occipital spikes in 29 patients. Of the other 14 cases, five had extraoccipital abnormalities or brief generalized discharges, and nine had normal awake and sleep EEG. Prognosis was excellent. All 43 children have been free of seizures for > or =2 years, 53% having a single seizure, and 47%, an average two to three seizures. CONCLUSIONS: Panayiotopoulos syndrome is common and needs wider recognition. EEG shows occipital or extraoccipital abnormalities, is normal in one third of patients, and does not determine clinical manifestations or prognosis, which is excellent despite the high prevalence of lengthy seizures.     

Jeavons syndrome existing as occipital cortex initiating generalized epilepsy

Purpose: Jeavons syndrome (JS) is one of the underreported epileptic syndromes characterized by eyelid myoclonia (EM), eye closure–induced seizures/electroencephalography (EEG) paroxysms, and photosensitivity. JS has been proposed as idiopathic generalized epilepsy (IGE) because of normal posterior dominant background activity and paroxysmal generalized ictal epileptiform discharges (EDs). However, we noticed subtle occipital EDs preceding EM and interictal posterior EDs using digital video‐EEG. We studied clinical and EEG findings in JS to determine the specific occipital lobe relation to this “eye closure–induced” reflex IGE. Methods: We identified 12 children who met the diagnostic criteria of JS from January 2004 to April 2009 at the Hospital for Sick Children, Toronto, Canada. All patients had EM captured by video‐EEG. We reviewed and described ictal EEG patterns, interictal abnormalities, and demographics, clinical, and neuroimaging findings. Key Findings: All patients but one were female (92%). Age at seizure onset ranged from 1.5 to 9 years, with a mean age of 4.9 years. Six patients (50%) were previously diagnosed as having absence epilepsy and 10 patients were on antiepileptic medications. All 12 patients had normal posterior dominant alpha rhythm, reactive to eye opening and closure. Spiky posterior alpha activity was noted with sustained eye closure in six patients (50%). Interictally, there were generalized EDs found in 10 patients (83%); four of them also had focal interictal EDs over the posterior head region. Eleven patients (92%) had evidence of focal posterior ictal EDs. EM and/or paroxysmal EDs were induced by photic stimulation in 9 (75%) and hyperventilation in 7 (58%). Significance: We observed two neurophysiologic findings in JS: (1) focal interictal EDs from posterior head region; and (2) predominant focal posterior ictal EDs preceding generalized EDs. Further clinical observations of seizures induced by eye closure, photic stimulation, and hyperventilation along with EEG paroxysms would raise the possibility of the occipital cortex initiating generalized epilepsy network involving the brainstem, and thalamocortical and transcortical pathways in JS.     

Adolescent Onset of Idiopathic Photosensitive Occipital Epilepsy After Remission of Benign Rolandic Epilepsy

Summary: Purpose: We describe 2 girls, aged 19 years, who experienced a rolandic seizure at ages 4 and 5, respectively, together with the interictal EEG features of benign rolandic epilepsy (BRE). In adolescence both patients developed photosensitive occipital seizures accompanied by spontaneous and photic-induced occipital EEG paroxysms.
Methods: We have been following 33 patients with a history of BRE, between ages 12 and 28 years (mean 17 years). Twenty-one of these patients had experienced their last rolandic seizure before the age of 10 years and 9 of them had been without treatment since age 11 or earlier. In 2 of these 9 patients, other types of seizures recurred after remission of BRE. Clinical, EEG, and evoked potential findings on these 2 patients are presented.
Results: After having experienced BRE, both patients suffered partial seizures from age 12, with elementary visual hallucinations, visual blurring, slow head turning, cephalic pain, epigastric discomfort, unresponsiveness, and vomiting. Seizure onset was related to watching TV or exposure to bright light. EEG showed interictal occipital spikes, and a photoparoxysmal response limited to the occipital lobes. Visual evoked potentials were greatly increased in amplitude. One patient had two visual attacks only and remained seizure free after 4 years of follow-up, while the other had seizures controlled by an association of valproate and carbamazepine.
Conclusions: Clinical and neurophysiological characteristics suggest that these two patients may have presented different age-related expressions within the spectrum of a benign seizure susceptibility syndrome rather than sharply distinct epilepsy syndromes.     

Clinical correlations of electroencephalographic occipital epileptiform paroxysms in children.

A longitudinal prospective approach was used to investigate clinical correlations of interictal occipital paroxysms with or without fixation-off sensitivity (FOS). Occipital paroxysms were recorded in the electroencephalograms (EEGs) of 76 children with heterogeneous clinical conditions including seizures in 39 patients. Occipital paroxysms with FOS (42 patients ) were only fractionally more frequent than non-FOS (34 patients ) and were not specific of any clinical condition. Although present and FOS-related in all 11 children with benign childhood epilepsies with occipital paroxysms (CEOP), they were also frequently encountered in symptomatic occipital epilepsy. The differentiation of CEOP from other syndromes established on clinical grounds could also be aided by the analysis of background EEG activity that was frequently significantly more abnormal in symptomatic than CEOP. Clinical characteristics and ictal seizure semiology as well as follow-up clearly distinguish two type of idiopathic CEOP syndromes: (1) early onset type or Panayiotopoulos syndrome characterized by excellent prognosis and rare, prolonged nocturnal seizures with tonic deviations of the eyes and vomiting, and (2) late onset or Gastaut type showing a common ictal visual symptomatology, co-occurrence of migraine, diurnal complex partial seizures and less favourable EEG-clinical prognosis.     

Ictal Behaviors During Nonepileptic Seizures Differ in Patients with Temporal Lobe Interictal Epileptiform EEG Activity and Patients Without Interictal Epileptiform EEG Abnormalities

Summary: Purpose: Ictal behaviors during psychogenic non-epileptic seizures (NES) vary considerably among individuals, and can closely resemble common semiologies of epileptic seizures (ES). We tested the hypothesis that behaviors during NES in patients who have temporal spikes would more closely resemble behaviors during ES in patients with temporal lobe epilepsy than would behaviors during NES in patients who do not have EEG spikes.
Methods: We identified 20 patients who had interictal temporal EEG spikes and EEG-video recorded NES (Study Group), 133 patients with temporal EEG spikes and recorded ES, without NES (Epileptic Group), and 24 patients with recorded NES and no epileptiform EEG abnormalities, without ES (Nonepileptic Group).
Results: The hypothesis was supported with regard to ictal motor behaviors. Motionless staring or complex automatisms occurred mainly during NES in the Study Group and during ES in the Epileptic Group. In contrast, convulsive movements or flaccid falls were most common during NES in the Nonepileptic Group. Duration of unresponsiveness was longer, and there were fewer postictal states in NES both in the Study and Non-epileptic Groups. Unresponsiveness was briefer and postictal states were more consistent in ES in the Epileptic Group, however.
Conclusions: Stereotyped motor activities during NES presumably represent learned behaviors. Processes underlying acquisition of ictal behaviors of NES probably differ in patients with interictal epileptiform EEG abnormalities compared to those without. Prior experiences and temporal lobe dysfunctions that are associated with epilepsy, and psychological characteristics that are unrelated to interictal epileptic dysfunctions, may determine ictal behaviors during NES.     

Panayiotopoulos-type benign childhood occipital epilepsy: a prospective study

OBJECTIVE: To characterize the clinical and EEG features of the syndrome of benign childhood partial seizures with ictal vomiting and EEG occipital spikes (Panayiotopoulos syndrome [PS]). METHODS: Prospective study of children with normal general and neurologic examinations who had seizures with ictal vomiting and EEG with occipital spikes. RESULTS: From February 1990 to 1997, the authors found 66 patients with PS and 145 children with benign childhood epilepsy with centrotemporal spikes. Peak age at onset of PS was 5 years. Ictal deviation of the eyes and progression to generalized seizures were common. One-third had partial status epilepticus. During sleep, all had seizures. While awake, one-third also had seizures. Five children with PS had concurrent symptoms of rolandic epilepsy and another five developed rolandic seizures after remission of PS. Prognosis was excellent: one-third had a single seizure, one-half had two to five seizures, and only 4.5% had frequent seizures. CONCLUSIONS: Panayiotopoulos-type benign childhood occipital epilepsy is less common than benign childhood epilepsy with centrotemporal spikes but is well defined and recognizable by clinical and EEG features.     

What is the Relationship Between Arachnoid Cysts and Seizure Foci?

Summary: Purpose: Arachnoid cysts are sometimes encountered in MRIs performed for a variety of reasons. In patients with epilepsy, particularly those with refractory epilepsy, arachnoid cysts are often assumed to be related to their seizure focus. We conducted a study to investigate this putative relationship.
Methods: A retrospective study on the incidence of arachnoid cysts was performed in patients seen in our Epilepsy Clinic who had CT or MRI scans, interictal EEGs or ictal EEGS. Locations of seizure foci in these patients were defined from clinical and electrophysiologic data.
Results: Seventeen of 867 patients had arachnoid cysts. Twelve patients had temporal lobe cysts and only 3 of them had temporal lobe seizures. Four patients had frontal lobe cysts and only 1 had frontal lobe seizures ipsilateral to the cyst. One patient had a cerebellopontine angle cyst and frontal lobe seizures. Thus, clinical manifestations of seizures and EEG findings (interictal and/or ictal) indicated that the seizure focus was adjacent to the cysts in only 4 patients (23.5%).
Conclusions: Our findings suggest that arachnoid cysts are often an incidental finding in patients with epilepsy and do not necessarily reflect the location of the seizure focus.     

Ictal Scalp EEG in Unilateral Mesial Temporal Lobe Epilepsy

Summary: Purpose: We wished to determine the predictive significance of unilateral hippocampal atrophy and interictal spikes on localization of ictal scalp EEG changes and assess whether ictal EEG provides information that might change treatment or influence prognosis in patients with such characteristics of epilepsy.
Methods: We analyzed EEG seizure patterns in 118 seizures in 24 patients with unilateral mesial temporal lobe epilepsy (MTLE) defined by typical clinical seizure semiology, unilateral hippocampal atrophy on magnetic resonance imaging (MRI) and unitemporal spikes on interictal EEG. Two blinded electroencephalographers independently determined morphology, location, and time course of ictal EEG changes.
Results: Lateralization was possible in 88.4–92.0% of seizures and always corresponded to the side of the interictal spike focus and of hippocampal atrophy on MRI. Although only 30.4–33.9% of seizures were lateralized at onset, a later significant pattern emerged (12.6–13.3 s after EEG seizure onset) that allowed lateralization in 82.4–91.O% of seizures with non-lateralized onset. Interobserver reliability for lateralization was excellent, with a K-value of 0.85. In most patients, either all (79.2–83.3%) or >50% (8.3–16.7%) of seizures were lateralized. In only a small proportion of patients (4.2–8.3%) were 40% of seizures lateralized. In 1 patient, no seizure could be lateralized by 1 electroencephalographer. The results of ictal EEG recordings did not alter the surgical approach and did not correlate with surgical outcome.
Conclusions: We conclude that unilateral hippocampal atrophy on MRI and unitemporal interictal spikes can predict localization of ictal scalp EEG changes with a high degree of reliability and that ictal EEG provides no additional localizing information in this particular patient group.     

Spatial and Temporal Characteristics of Neonatal Seizures

Summary: Thirty-two neonates (26 term and 6 premature) having seizures were prospectively recruited and studied. Using prolonged video/EEG monitoring, we quantified seizure variables (electrographic and clinical seizure durations, interictal periods and electrographic seizure spread) for all 1,420 seizures recorded. The effects of time and antiepileptic drug (AED) therapy were analyzed statistically. Seizures were generally frequent, with limited electrographic spread. However, some neonates had consistently longer interictal periods and 13% had mean interictal periods >60 min. Seizure variables were relatively stable over time, but they changed with AED therapy. There was a trend to decreased seizure duration, increased length of interictal periods, and decreased electrographic spread. Furthermore, there was evidence of reduced clinical features after sequential AED infusions. Seizures ceased during the monitoring period in 22 neonates. Eighty-five percent of all seizures had no clinical manifestations. Among neonates with clear clinical correlates, clinical observations underestimated electrographic seizures in individual neonates by a mean of 54% (range 0–95%). Seizures generally had limited electrographic spread. Use of only four recording electrodes, characteristic of some portable EEG systems, underestimated seizures in 19 neonates, and missed all seizures in 2.     

The localizing value of ictal EEG in focal epilepsy.

OBJECTIVE: To investigate the lateralization and localization of ictal EEG in focal epilepsy. METHODS: A total of 486 ictal EEG of 72 patients with focal epilepsy arising from the mesial temporal, neocortical temporal, mesial frontal, dorsolateral frontal, parietal, and occipital regions were analyzed. RESULTS: Surface ictal EEG was adequately localized in 72% of cases, more often in temporal than extratemporal epilepsy. Localized ictal onsets were seen in 57% of seizures and were most common in mesial temporal lobe epilepsy (MTLE), lateral frontal lobe epilepsy (LFLE), and parietal lobe epilepsy, whereas lateralized onsets predominated in neocortical temporal lobe epilepsy and generalized onsets in mesial frontal lobe epilepsy (MFLE) and occipital lobe epilepsy. Approximately two-thirds of seizures were localized, 22% generalized, 4% lateralized, and 6% mislocalized/lateralized. False localization/lateralization occurred in 28% of occipital and 16% of parietal seizures. Rhythmic temporal theta at ictal onset was seen exclusively in temporal lobe seizures, whereas localized repetitive epileptiform activity was highly predictive of LFLE. Seizures arising from the lateral convexity and mesial regions were differentiated by a high incidence of repetitive epileptiform activity at ictal onset in the former and rhythmic theta activity in the latter. CONCLUSIONS: With the exception of mesial frontal lobe epilepsy, ictal recordings are very useful in the localization/lateralization of focal seizures. Some patterns are highly accurate in localizing the epileptogenic lobe. One limitation of ictal EEG is the potential for false localization/lateralization in occipital and parietal lobe epilepsies.     

Early-Onset Benign Childhood Occipital Seizure Susceptibility Syndrome: A Syndrome to Recognize

Early-onset benign childhood occipital seizures (EBOS) described by Panayiotopoulos constitute the commoner after the rolandic phenotype of a childhood seizure susceptibility syndrome. EBOS are the clinical representative of occipital spikes. Their cardinal features are infrequent (often single) partial seizures manifested with deviation of the eyes and vomiting, frequently evolving to hemi- or generalized convulsions. Ictal behavioral changes, irritability, pallor, and rarely cyanosis, and eyes wide open are frequent. Retching, coughing, aphemia, oropharyngolaryngeal movements, and incontinence may occur. Consciousness is usually impaired or lost, either from the onset or the course of the fits, but in a few children, it may be preserved. Duration varies from a few minutes to hours (partial status epilepticus). Seizures are usually nocturnal, but semiology is similar in nocturnal or diurnal fits. Onset is between 1 and 12 years with a peak at 5 years. One third of children have a single seizure, the median total number of fits is two to three, and the prognosis is invariably excellent, with remission usually occurring within 1 year from onset. A few children may later develop rolandic or other benign partial seizures. The likelihood to have seizures after age 12 years is exceptional and rarer than that of febrile convulsions. EEG shows occipital paroxysms demonstrating fixation-off sensitivity, but random occipital spikes, occipital spikes in sleep EEG alone, or normal EEG may occur. Centrotemporal and other spike foci may appear in the same or more frequently in subsequent EEGs. The EEG does not reflect clinical course and severity.     

Occipital lobe epilepsy: clinical characteristics, seizure spread patterns, and results of surgery.

Twenty-five patients with occipital lobe seizure origin were retrospectively evaluated to determine clinical seizure characteristics and electroencephalographic manifestations. Certain symptoms and signs served to identify occipital lobe origin in 22 (88%). These included elementary visual hallucinations, ictal amaurosis, eye movement sensations, early forced blinking or eyelid flutter, and visual field deficits. Eye or head deviation, or both, was observed frequently and was contralateral to the side of seizure origin in 13, but 3 patients exhibited ipsilateral deviation in some or all their seizures. After the initial signs and symptoms, clinical seizure characteristics resembled those of seizures originating elsewhere. Seizures typical of temporal lobe origin with loss of contact and various types of automatic, semipurposeful activity occurred in 11 patients. Seizures in 3 patients exhibited asymmetrical tonic or focal clonic motor patterns characteristic of frontal lobe seizures. Eleven of the 25 patients had, on two occasions, two or more distinctly different seizure types. Scalp electroencephalographic findings were seldom helpful for occipital lobe localization and were frequently misleading. Intracranial electroencephalographic recording correctly identified occipital lobe seizure origin in most, but not all, patients who had such studies. Intracranial electroencephalic recording also proved the variability in clinical seizure characteristics was related to different seizure spread patterns, medially or laterally above and below the sylvian fissure, both ipsilateral and contralateral to the occipital lobe of seizure origin. Eighteen patients had occipital lobe lesions detected with computed tomographic or magnetic resonance imaging scans or both. Resection of the lesions in 16 patients produced excellent results in 14 (88%). Five patients had temporal lobectomies, with good results in 3, but poor results in 2. Two patients with unlocalized seizures had complete section of the corpus callosum, 1 with a good result and the other with a poor result.     

Ictal EEG Changes with Corpus Callosum Section

Summary: Corpus collosum section diminishes but does not completely abolish secondary bilaterally synchronous interictal EEG discharges, yet often causes cessation of generalized seizures. The effects of corpus callosum section on ictal EEG patterns have not been described. We contrasted ictal EEG patterns before and after anterior callosotomy in 18 patients and before and after total callosotomy in 10 patients. Bilaterally synchronous seizure onset was disrupted in 5 of 11 anterior section patients and 5 of 5 total section patients. Seven of 18 anterior section patients and 5 of 10 total section patients had more localized seizure onset after the procedure; localization to the frontal lobe was observed after anterior or total section, but only total section patients had newly demonstrated posterior locations of seizure onset. These data suggest that the mechanisms by which bilaterally synchronous interictal and ictal discharges are generated differ. Although brainstem or diencephalic structures may contribute to formation of interictal bilateral synchrony, the corpus callosum may be the only pathway used in producing apparent bilateral synchronous seizure onset in patients with secondarily generalized seizures.     

视频脑电图监测对癫痫的诊断价值

目的探讨视频脑电图(Video-EEG)对癫痫的诊断价值.方法对252例发作性疾病患者进行连续12～24小时监测,其中包括清醒、睡眠及诱发试验,分析临床发作和异常放电的关系,异常放电出现的时相,癫痫分型与异常放电的关系,临床发作前脑电图的改变以及临床发作间期和发作期异常脑电图的不同表现.结果252例监测到临床发作142例,其中同时伴异常放电者为111例;252例检出异常放电187例,其中出现于睡眠期者146例;确诊的111例中103例确定了发作类型,其中25例修正了发作类型;确诊的111例监测到发作前脑电图的异常改变,表现为背景脑电波频率和波幅的改变,或者出现痫样放电;111例不同发作类型癫痫患者发作间期和发作期有不同的异常脑电图表现.结论视频脑电图可提高痫样放电的检出率,有助于癫痫的诊断及分型,有利于观察癫痫患者发作间期及发作期脑电图的表现.     

Childhood epilepsy with occipital paroxysms: difficulties in distinct segregation into either the early-onset or late-onset epilepsy subtypes

The Commission on Classification and Terminology of the International League Against Epilepsy Childhood rigidly segregated epilepsy with occipital paroxysms into 2 separate syndromes with different predominant seizure types: early-onset seizure susceptibility type consisting of prolonged infrequent, nocturnal autonomic seizures and accompanied by eye deviation and ictal vomiting and late onset with short diurnal frequent seizures and visual ictal manifestations along with throbbing headaches. Epileptic clinical manifestations and electroencephalographic data were analyzed in 28 patients with suspected occipital lobe epilepsy in an attempt to segregate them into either the early or late forms according to the International League Against Epilepsy classification. Electroencephalography in 25 children demonstrated occipital epileptiform paroxysms compatible with the suspected epileptic syndrome. Only 14 (50%) children complied with the rigid criteria of either early-onset or late-onset presentations. The other 14 (50%) children presented with mixed diverse epileptic phenomena such as short-lived seizures in infancy or prolonged seizures during childhood, not complying with either rigid syndrome (ie, short-lived epileptic blindness at an early age or vomiting during later childhood). Despite present attempts to rigidly segregate childhood epilepsy with occipital paroxysms into 2 distinct epileptic syndromes, a high percentage of children still present with various mixed clinical phenomena. Therefore, clinicians should be aware of possible unique and unusual presentations of occipital lobe epilepsy at various ages.     

Clinical Value of "Ictal" FDG-Positron Emission Tomography and the Routine Use of Simultaneous Scalp EEG Studies in Patients with Intractable Partial Epilepsies

Summary: Purpose: EEG is widely used during positron emission tomography (PET) to confirm the interictal state of the patient and assist in scan interpretation when a seizure occurs. Ictal scans usually reflect mixed interictal-ictal-postictal metabolic activity as seizures are brief in comparison to the 30-min uptake period of the tracer. We wished to determine whether routine EEG is justified and if seizures commonly affect the diagnostic information of the PET scan.
Methods: We examined the PET scans of 6 of 236 outpatients with intractable epilepsy with clinical and electrical evidence of a seizure during tracer uptake. We performed semi-quantitative analysis in 2 patients who had "ictal" and control interictal scans.
Results: Patients with single seizures lasting 23 s to 4 min [four complex partial seizures (CPS) and one absence seizure (AS)] had focal hypometabolism concordant with results of other investigations. One patient with complex partial status had irregular cortical uptake and focal hypometabolism, but the site of the ictal focus could not be confirmed.
Conclusions: In this group of patients, seizures occurred infrequently during tracer uptake. The interpretation of the PET scan when single seizures occurred did not appear to be influenced by the continuous scalp EEG (CSEEG) recordings. The value of routine CSEEG in outpatients treated with medication should be reappraised, with potential cost savings. In rare circumstances in which a true ictal study occurs (complex partial status, epilepsia partialis continua, and repetitive CPS), PET scanning may be inconclusive and repeat interictal scanning should be pursued.     

Dipole Modeling in Epilepsy Surgery Candidates

Summary: Purpose : The validity and clinical significance of dipole modeling in epilepsy surgery candidates is not fully established.
Patients and Methods : Interictal and ictal dipole modeling was performed in 43 patients with refractory complex partial seizures (CPS) and intracranial structural abnormalities demonstrated with optimum magnetic resonance imaging (MRI: space–occupying, n = 15; atrophic, n = 26; dysplastic, n = 2). Video–EEG monitoring showed CPS in all patients. In 12 patients, additional intracranial EEG monitoring demonstrated hippocampal seizure onset in 11 patients and medial occipital ictal onset in 1.
Results : Spatiotemporal dipole mapping of averaged interictal spikes and epochs of early ictal discharges revealed two distinct dipole patterns. Patients with lesions located in the medial (± lateral) temporal lobe (n = 34) and medial occipital lobe (n = 1) uniformly presented a combined interictal dipole that consisted of a radial and a tangential component with a high degree of elevation relative to the axial plane. Eight of 9 patients with extratemporal lesions had a less stable dipole with a predominant radial component. Ictal dipole modeling identified the ictal onset zone correctly as compared with intracranial EEG recordings from bilateral hippocampal depth electrodes. Ictal dipoles showed a striking correspondence with the interictal dipoles in individual patients.
Conclusions : Interictal and ictal dipole mapping provided additional, reliable, and relevant localizing information in surgical candidates for refractory CPS. Ictal dipole analysis may limit the number of patients who require intracranial electrodes.     

Five-Year Outcome After Epilepsy Surgery in Nonmonitored and Monitored Surgical Candidates

Summary: Purpose : We wished to compare outcome 5 years after temporal lobectomy in 28 patients selected for surgery on the basis of interictal EEG patterns with that in 46 patients who underwent EEG-video monitoring studies as part of their preoperative evaluation during the same era.
Methods : The 28 nonmonitored patients had interictal EEG patterns that demonstrated a consistent, unilateral, anterior-midtemporal epileptiform focus, without discordant findings from other studies. Outcomes were assessed for years 4 and 5 after operation.
Results : Twenty-six of 28 (92.9%) nonmonitored patients were seizure-free or had at least 75% reduction in seizures. Twenty-nine of 46 (63.0%) monitored patients were seizure-free or had at least 75% reduction in seizures. Preoperative interictal EEGs of 29 of these patients showed independently localized bitemporal, ex-tratemporal, midposterior temporal, or diffuse epileptiform patterns. The remaining 17 monitored patients had preoperative strictly unilateral anterior-midtemporal interictal discharges, and their outcome was comparable to the nonmonitored group, with 15 (88.8%) seizure-free or with at least 75% reduction in seizures.
Conclusions : A proportion of candidates for epilepsy surgery can be selected without ictal recordings provided that interictal EEGs demonstrate consistent unilateral anterior-midtemporal epileptiform discharges and that other data are not discordant.     

A Stereoelectroencephalographic (SEEG) Study of Light-Induced Mesiotemporal Epileptic Seizures

Summary: Purpose: This study explored the mechanism of light-induced complex partial seizures by using ictal intracerebral recordings in a patient with refractory epilepsy of the right temporal lobe.
Methods: Presurgical evaluation of this patient was realized by means of video-EEG recordings, WADA test, magnetic resonance imaging (MRI), F¹⁸-deoxyglucose and C¹¹-flumazenil positron emission tomography (PET) interictal neuroimaging data, and stereoelectroencephalographic (SEEG) ictal recordings.
Results: SEEG investigations demonstrated the right mesiotemporal origin of all the patient's seizures. This result was confirmed by a successful right temporal lobectomy. Moreover, SEEG recordings revealed a frequent interictal spiking activity in the right occipital visual cortex that was undetectable on scalp recordings. However, the occipital cortex was not involved at the onset of mesiotemporal ictal discharges and was not hyperresponsive to focal electrical stimulation.
Conclusions: This study shows that, in spite of interictal occipital spiking, the photosensitivity of mesiotemporal seizures can be observed in both the absence of occipital cortex involvement during ictal discharges and demonstrable hyper-excitability of the occipital cortex to light or direct electrical stimulation.