Occipital lobe developmental malformations and epilepsy: clinical spectrum, treatment, and outcome

Glymphatic system dysfunction in patients with occipital lobe epilepsy

BACKGROUND AND PURPOSE

We aimed to investigate the glymphatic system function in patients with occipital lobe epilepsy (OLE) and healthy controls using diffusion tensor image analysis along the perivascular space (DTI-ALPS) index.

METHODS

We retrospectively included 23 patients with OLE and 30 healthy controls. The participants underwent brain MRI, which was normal, and diffusion tensor imaging. We used the DSI Studio for data preprocessing, obtained the fiber orientation and diffusivities, and calculated the DTI-ALPS index from the diffusivity values associated with the projection and association fibers in the left hemisphere.

RESULTS

There were no differences in mean age (31.6 years [range: 13-58] vs. 31.3 years [range: 20-57], p = .912) and male sex ratio (10/23 [43.5%] vs. 15/30 [50.0%]) between the groups. Compared to healthy controls, the diffusivities in patients with OLE were higher along the Y-axis in the projection fiber and along the Z-axis in the association fiber and lower along the Y-axis in the association fiber. The DTI-ALPS index in patients with OLE was lower than that in the healthy controls (1.421 ± 0.171 vs. 1.667 ± 0.271, p < .001, 95% confidence interval of difference = 0.117-0.376, Test statistic t = 3.823). We found no association between the DTI-ALPS index and clinical characteristics in OLE.

CONCLUSION

The DTI-ALPS index in patients with OLE was significantly lower than that in healthy controls, suggesting glymphatic system dysfunction in OLE. The DTI-ALPS index could help assess the glymphatic system function in patients with epilepsy.

Clinical features of automatisms and correlation with the seizure onset zones: A cluster analysis of 74 surgically-treated cases

OBJECTIVES

To identify semiologic features of automatisms correlating to different seizure onset zones (SOZ).

METHODS

In total, 204 seizures from 74 patients with either oral or manual automatisms were assessed. Patients were divided into four groups depending on the SOZ into frontal, posterior, neocortical temporal, and mesial temporal cortex groups. A k-means analysis was applied on 11 semiologic features on a multi-criteria scale. Then, the resulting clinical patterns were correlated with the SOZs determined by presurgical anatomy-electroclinical data (25 cases with stereo-EEG).

RESULTS

Four clinical patterns of automatisms with different accompanying symptoms were identified. The clinical features of clusters 1 and 4 were mostly found in temporal epilepsy whereas clusters 2 and 3 were more frequent in extratemporal epilepsy. Cluster 1 was significantly correlated with mesial temporal lobe epilepsy (p = .017) and was characterised by aura, postictal confusion, short automatisms delay. Cluster 3 included 1/3 patients with frontal lobe epilepsy and was characterised by emotionality. Cluster 4 was related to neocortical temporal lobe epilepsy and characterised by dystonia and short automatism delay (p = .011).

CONCLUSION

The distinct semiologic patterns of automatisms may provide information which may allow clinicians to define the SOZs. These findings could improve diagnostic accuracy and surgical outcome.

Resection of bilateral occipital lobe lesions during a single operation as a treatment for bilateral occipital lobe epilepsy

BACKGROUND

Neurosurgical treatment of severe bilateral occipital lobe epilepsy usually involves two operations several mos apart.

AIM

To evaluate surgical resection of bilateral occipital lobe lesions during a single operation as a treatment for bilateral occipital lobe epilepsy.

METHODS

This retrospective case series included patients with drug-refractory bilateral occipital lobe epilepsy treated surgically between March 2006 and November 2015.

RESULTS

Preoperative evaluation included scalp video-electroencephalography (EEG), magnetic resonance imaging, and PET-CT. During surgery (bilateral occipital craniotomy), epileptic foci and important functional areas were identified by EEG (intracranial cortical electrodes) and cortical functional mapping, respectively. Patients were followed up for at least 5 years to evaluate treatment outcome (Engel grade) and visual function. The 20 patients (12 males) were aged 4-30 years (median age, 12 years). Time since onset was 3-20 years (median, 8 years), and episode frequency was 4-270/mo (median, 15/mo). Common manifestations were elementary visual hallucinations (65.0%), flashing lights (30.0%), blurred vision (20.0%) and visual field defects (20.0%). Most patients were free of disabling seizures (Engel grade I) postoperatively (18/20, 90.0%) and at 1 year (18/20, 90.0%), 3 years (17/20, 85.0%) and ≥ 5 years (17/20, 85.0%). No patients were classified Engel grade IV (no worthwhile improvement). After surgery, there was no change in visual function in 13/20 (65.0%), development of a new visual field defect in 3/20 (15.0%), and worsening of a preexisting defect in 4/20 (20.0%).

CONCLUSION

Resection of bilateral occipital lobe lesions during a single operation may be applicable in bilateral occipital lobe epilepsy.

Seizures in meningioma

More than one-third of patients with meningiomas will experience seizures at some point in their disease. Despite this, meningioma-associated epilepsy remains significantly understudied, as most investigations focus on tumor progression, extent of resection, and survival. Due to the impact of epilepsy on the patient's quality of life, identifying predictors of preoperative seizures and postoperative seizure freedom is critical. In this chapter, we review previously reported rates and predictors of seizures in meningioma and discuss surgical and medical treatment options. Preoperative epilepsy occurs in approximately 30% of meningioma patients with peritumoral edema on neuroimaging being one of the most significant predictor of seizures. Other associated factors include age <18, male gender, the absence of headache, and non-skull base tumor location. Following tumor resection, approximately 70% of individuals with preoperative epilepsy achieve seizure freedom. Variables associated with persistent seizures include a history of preoperative epilepsy, peritumoral edema, skull base tumor location, tumor progression, and epileptiform discharges on postoperative electroencephalogram. In addition, after surgery, approximately 10% of meningioma patients without preoperative epilepsy experience new seizures. Variables associated with new postoperative seizures include tumor progression, prior radiation exposure, and gross total tumor resection. Both pre- and postoperative meningioma-related seizures are often responsive to antiepileptic drugs (AEDs), although AED prophylaxis in the absence of seizures is not recommended. AED selection is based on current guidelines for treating focal seizures with additional considerations including efficacy in tumor-related epilepsy, toxicities, and potential drug-drug interactions. Continued investigation into medical and surgical strategies for preventing and alleviating epilepsy in meningioma is warranted.

Awake perimetry testing for occipital epilepsy surgery

With the patient awake during surgery, the authors used a simple technique to determine which part of a patient's brain was essential for vision. This technique allows the surgeon to remove as much as the seizure-producing brain as possible by avoiding the areas that are critical for vision.

Seizure Outcomes in Occipital Lobe and Posterior Quadrant Epilepsy Surgery: A Systematic Review and Meta-Analysis

BACKGROUND

Occipital lobe epilepsy (OLE) is an uncommon but debilitating focal epilepsy syndrome with seizures often refractory to medical management. While surgical resection has proven a viable treatment, previous studies examining postoperative seizure freedom rates are limited by small sample size and patient heterogeneity, thus exhibiting significant variability in their results.

OBJECTIVE

To review the medical literature on OLE so as to investigate rates and predictors of both seizure freedom and visual outcomes following surgery.

METHODS

We reviewed manuscripts exploring surgical resection for drug-resistant OLE published between January 1990 and June 2015 on PubMed. Seizure freedom rates were analyzed and potential predictors were evaluated with separate meta-analyses. Postoperative visual outcomes were also examined.

RESULTS

We identified 27 case series comprising 584 patients with greater than 1 yr of follow-up. Postoperative seizure freedom (Engel class I outcome) was observed in 65% of patients, and was significantly predicted by age less than 18 yr (odds ratio [OR] 1.54, 95% confidence interval [CI] 1.13-2.18), focal lesion on pathological analysis (OR 2.08, 95% CI 1.58-2.89), and abnormal preoperative magnetic resonance imaging (OR 3.24, 95% 2.03-6.55). Of these patients, 175 also had visual outcomes reported with 57% demonstrating some degree of visual decline following surgery. We did not find any relationship between postoperative visual and seizure outcomes.

CONCLUSION

Surgical resection for OLE is associated with favorable outcomes with nearly two-thirds of patients achieving postoperative seizure freedom. However, patients must be counseled regarding the risk of visual decline following surgery.

Relationship between cortical resection and visual function after occipital lobe epilepsy surgery

OBJECTIVE In this study, the authors investigated long-term clinical and visual outcomes of patients after occipital lobe epilepsy (OLE) surgery and analyzed the relationship between visual cortical resection and visual function after OLE surgery. METHODS A total of 42 consecutive patients who were diagnosed with OLE and underwent occipital lobe resection between June 1995 and November 2013 were included. Clinical, radiological, and histopathological data were reviewed retrospectively. Seizure outcomes were categorized according to the Engel classification. Visual function after surgery was assessed using the National Eye Institute Visual Functioning Questionnaire 25. The relationship between the resected area of the visual cortex and visual function was demonstrated by multivariate linear regression models. RESULTS After a mean follow-up period of 102.2 months, 27 (64.3%) patients were seizure free, and 6 (14.3%) patients had an Engel Class II outcome. Nineteen (57.6%) of 33 patients had a normal visual field or quadrantanopia after surgery (normal and quadrantanopia groups). Patients in the normal and quadrantanopia groups had better vision-related quality of life than those in the hemianopsia group. The resection of lateral occipital areas 1 and 2 of the occipital lobe was significantly associated with difficulties in general vision, peripheral vision, and vision-specific roles. In addition, the resection of intraparietal sulcus 3 or 4 was significantly associated with decreased social functioning. CONCLUSIONS The authors found a favorable seizure control rate (Engel Class I or II) of 78.6%, and 57.6% of the subjects had good visual function (normal vision or quadrantanopia) after OLE surgery. Lateral occipital cortical resection had a significant effect on visual function despite preservation of the visual field.

Occipital and occipital "plus" epilepsies: A study of involved epileptogenic networks through SEEG quantification

Compared with temporal or frontal lobe epilepsies, the occipital lobe epilepsies (OLE) remain poorly characterized. In this study, we aimed at classifying the ictal networks involving OLE and investigated clinical features of the OLE network subtypes. We studied 194 seizures from 29 consecutive patients presenting with OLE and investigated by stereoelectroencephalography (SEEG). Epileptogenicity of occipital and extraoccipital regions was quantified according to the 'epileptogenicity index' (EI) method. We found that 79% of patients showed widespread epileptogenic zone organization, involving parietal or temporal regions in addition to the occipital lobe. Two main groups of epileptogenic zone organization within occipital lobe seizures were identified: a pure occipital group and an occipital "plus" group, the latter including two further subgroups, occipitotemporal and occipitoparietal. In 29% of patients, the epileptogenic zone was found to have a bilateral organization. The most epileptogenic structure was the fusiform gyrus (mean EI: 0.53). Surgery was proposed in 18/29 patients, leading to seizure freedom in 55% (Engel Class I). Results suggest that, in patient candidates for surgery, the majority of cases are characterized by complex organization of the EZ, corresponding to the occipital plus group.

The Classical Pathways of Occipital Lobe Epileptic Propagation Revised in the Light of White Matter Dissection

The clinical evidences of variable epileptic propagation in occipital lobe epilepsy (OLE) have been demonstrated by several studies. However the exact localization of the epileptic focus sometimes represents a problem because of the rapid propagation to frontal, parietal, or temporal regions. Each white matter pathway close to the supposed initial focus can lead the propagation towards a specific direction, explaining the variable semiology of these rare epilepsy syndromes. Some new insights in occipital white matter anatomy are herein described by means of white matter dissection and compared to the classical epileptic patterns, mostly based on the central position of the primary visual cortex. The dissections showed a complex white matter architecture composed by vertical and longitudinal bundles, which are closely interconnected and segregated and are able to support specific high order functions with parallel bidirectional propagation of the electric signal. The same sublobar lesions may hyperactivate different white matter bundles reemphasizing the importance of the ictal semiology as a specific clinical demonstration of the subcortical networks recruited. Merging semiology, white matter anatomy, and electrophysiology may lead us to a better understanding of these complex syndromes and tailored therapeutic options based on individual white matter connectivity.

Intractable occipital lobe epilepsy: clinical characteristics, surgical treatment, and a systematic review of the literature

PURPOSE

We reported our experience in the surgical treatment of a relatively large cohort of patients with occipital lobe epilepsy (OLE). We also carried out a systematic review of the literature on OLE.

METHODS

Thirty-five consecutive patients who underwent occipital resection for epilepsy were included. Diagnoses were made following presurgical evaluations, including magnetic resonance imaging (MRI), fluorodeoxyglucose-positron emission tomography (FDG-PET), scalp video-electroencephalogram (EEG) monitoring, and intracranial EEG monitoring. At last follow-up, seizure outcome was classified using the Engel classification scheme.

RESULTS

Twenty-five of 35 patients experienced/had experienced ≥1 type of aura before the seizure. Invasive recordings were used to define the epileptogenic area in 30 of 35 patients (85.7 %). All patients underwent occipital lesionectomies or topectomies. Histopathology revealed: cortical dysplasias, gliosis, dysembryoplastic neuroepithelial tumor, ganglioglioma, and tuberous sclerosis. After a mean follow-up of 44 months, 25 patients (71.4 %) were seizure free (Engel class I), 3 (8.6 %) rarely had seizures (Engel class II), 5 (14.3 %) improved more than 75 % (Engel class III), and 2 (5.7 %) had no significant improvement (Engel class IV). Preoperatively, 12 of 33 patients (36.4 %) had visual field deficits. Postoperatively, 25 patients (75.8 %) had new or aggravated visual field deficits.

CONCLUSIONS

The management of OLE has been aided greatly by the availability of high-resolution diagnosis. Postoperative visual field deficits occur in a significant proportion of patients. Comprehensive intracranial EEG coverage of all occipital surfaces helps to define the epileptogenic area and preserve visual function, especially in cases of focal cortical dysplasia undetectable by MRI.

The pathology of magnetic-resonance-imaging-negative epilepsy

Patients with magnetic-resonance-imaging (MRI)-negative (or 'nonlesional') pharmacoresistant focal epilepsy are the most challenging group undergoing presurgical evaluation. Few large-scale studies have systematically reviewed the pathological substrates underlying MRI-negative epilepsies. In the current study, histopathological specimens were retrospectively reviewed from MRI-negative epilepsy patients (n=95, mean age=30 years, 50% female subjects). Focal cortical dysplasia cases were classified according to the International League Against Epilepsy (ILAE) and Palmini et al classifications. The most common pathologies found in this MRI-negative cohort included: focal cortical dysplasia (n=43, 45%), gliosis (n=21, 22%), hamartia+gliosis (n=12, 13%), and hippocampal sclerosis (n=9, 9%). The majority of focal cortical dysplasia were ILAE type I (n=37) or Palmini type I (n=39). Seven patients had no identifiable pathological abnormalities. The existence of positive pathology was not significantly associated with age or temporal/extratemporal resection. Follow-up data post surgery was available in 90 patients; 63 (70%) and 57 (63%) attained seizure freedom at 6 and 12 months, respectively. The finding of positive pathology was significantly associated with seizure-free outcome at 6 months (P=0.035), but not at 12 months. In subgroup analysis, the focal cortical dysplasia group was not significantly correlated with seizure-free outcome, as compared with the negative-pathology groups at either 6 or 12 months. Of note, the finding of hippocampal sclerosis had a significant positive correlation with seizure-free outcome when compared with the negative-pathology group (P=0.009 and 0.004 for 6- and 12-month outcome, respectively). Absence of a significant histopathology in the resected surgical specimen did not preclude seizure freedom. In conclusion, our study highlights the heterogeneity of epileptic pathologies in MRI-negative epilepsies, with focal cortical dysplasia being the most common finding. The existence of positive pathology in surgical specimen may be a good indication for short-term good seizure outcome. There is a small subset of cases in which no pathological abnormalities are identified.

Occipital lobe seizures and epilepsies

Occipital lobe epilepsies (OLEs) manifest with occipital seizures from an epileptic focus within the occipital lobes. Ictal clinical symptoms are mainly visual and oculomotor. Elementary visual hallucinations are common and characteristic. Postictal headache occurs in more than half of patients (epilepsy-migraine sequence). Electroencephalography (EEG) is of significant diagnostic value, but certain limitations should be recognized. Occipital spikes and/or occipital paroxysms either spontaneous or photically induced are the main interictal EEG abnormalities in idiopathic OLE. However, occipital epileptiform abnormalities may also occur without clinical relationship to seizures particularly in children. In cryptogenic/symptomatic OLE, unilateral posterior EEG slowing is more common than occipital spikes. In neurosurgical series of symptomatic OLE, interictal EEG abnormalities are rarely strictly occipital. The most common localization is in the posterior temporal regions and less than one-fifth show occipital spikes. In photosensitive OLE, intermittent photic stimulation elicits (1) spikes/polyspikes confined in the occipital regions or (2) generalized spikes/polyspikes with posterior emphasis. In ictal EEG, a well-localized unifocal rhythmic ictal discharge during occipital seizures is infrequent. A bioccipital field spread to the temporal regions is common. Frequency, severity, and response to treatment vary considerably from good to intractable and progressive mainly depending on underlying causes.

Anticonvulsant drugs in bipolar disorder

Although much progress has been made in successfully treating bipolar disorder, there is increasing awareness of the limitations of traditional treatment regimens such as lithium and neuroleptics. The large family of anticonvulsant drugs, however, appears to be capable of providing new treatment options, not only as medication of second choice in patients refractory to treatment, but often as a treatment standard with high efficacy and low incidence of side effects. Besides established mood stabilizers such as carbamazepine and valproate, new antiepileptic drugs are entering the field with promising initial results in the treatment of bipolar patients. Furthermore, bringing to light the mechanisms of action of anticonvulsants and the similarities between anticonvulsants effective in bipolar disorder may also deepen our understanding of the pathophysiological basis of the disorder.

Hallucinations and reversed cerebral dominance in mesial temporal sclerosis

The localizing value of experiential phenomena in temporal and occipital lobe epilepsy has become increasingly elucidated. We describe complex visual and auditory hallucinations in a right-handed adolescent and review the localization value of ictal visual and auditory auras in partial epilepsy. A 15-year-old right-handed girl with 2 previous secondarily generalized seizures manifested a new semiology of complex visual and auditory hallucinations, characterized by seeing a school bus full of children and then hearing a male voice tell her to "feed the children." Feeling compelled, she "fed" the children, and they reboarded the bus and the bus drove away. Video electroencephalogram monitoring demonstrated fluent language during her seizures. Magnetic resonance imaging was compatible with left mesial temporal sclerosis. Fluorodeoxyglucose positron emission tomography demonstrated left temporal hypometabolism. An ictal single-photon emission computed tomography study demonstrated left anterior temporal hyperperfusion; Wada testing revealed reversed cerebral dominance. The patient underwent left anterior temporal lobectomy without complication and remains seizure-free. Complex auditory and visual hallucinations can occur in occipitotemporal and anteromedial temporal epilepsy. Reversed cerebral dominance is more common in children than adults and should be considered in any dextral person with fluent ictal speech with a left-sided epileptogenic lesion.

Hypoglycemia-occipital syndrome: a specific neurologic syndrome following neonatal hypoglycemia?

This study attempted to elaborate the existence of a specific neurologic pattern observed in children who experienced neonatal hypoglycemia. Twenty-seven patients with seizure and history of neonatal hypoglycemia were compared with 28 children suffering from idiopathic occipital epilepsy. In both groups the most common type of seizure activities included eye movements and impaired consciousness responding well to treatment; however, ictal vomiting was more common in controls. Subjects were in epileptic and nonepileptic groups. Ninety percent of cases showed abnormal signal of the posterior head region on magnetic resonance imaging (MRI). A large number showed posterior abnormalities on electroencephalography (EEG). Visual loss with abnormal visual evoked potential was the most frequent visual finding. Fifty-five percent showed mild psychomotor retardation. This study demonstrates that neonatal hypoglycemia can induce a syndrome with a specific clinical spectrum consisting of epilepsy, visual disturbances, and psychomotor retardation. Hypoglycemia-occipital syndrome is an entity without statistically significant semiologic differences from the idiopathic type.

Plasticity of the visual system after early brain damage

The aim of this review is to discuss the existing evidence supporting different processes of visual brain plasticity after early damage, as opposed to damage that occurs during adulthood. There is initial evidence that some of the neuroplastic mechanisms adopted by the brain after early damage to the visual system are unavailable at a later stage. These are, for example, the ability to differentiate functional tissue within a larger dysplastic cortex during its formation, or to develop new thalamo-cortical connections able to bypass the lesion and reach their cortical destination in the occipital cortex. The young brain also uses the same mechanisms available at later stages of development but in a more efficient way. For example, in people with visual field defects of central origin, the anatomical expansion of the extrastriatal visual network is greater after an early lesion than after a later one, which results in more efficient mechanisms of visual exploration of the blind field. A similar mechanism is likely to support some of the differences found in people with blindsight, the phenomenon of unconscious visual perception in the blind field. In particular, compared with people with late lesions, those with early brain damage appear to have stronger subjective awareness of stimuli hitting the blind visual field, reported as a conscious feeling that something is present in the visual field. Expanding our knowledge of these mechanisms could help the development of early therapeutic interventions aimed at supporting and enhancing visual reorganization at a time of greatest potential brain plasticity.

Surgery for extratemporal nonlesional epilepsy in adults: an outcome meta-analysis

PURPOSE

To better evaluate surgery for extratemporal lobe epilepsy (ETLE) in adults, we conducted a meta-analysis of previous studies that analyzed postoperative seizure outcomes for ETLE.

METHODS

After searching PubMed for appropriate studies, patient data were reviewed, and data on patients who fit the authors' criteria were extracted. Statistical analysis compared each variable with surgical outcome to determine if an association existed.

RESULTS

For the 131 patients who were included in the analysis, the age at surgery, age of seizure onset, and duration of epilepsy were not found to be statistically and significantly related to seizure outcome. Similarly, seizure semiology, abnormality on magnetic resonance imaging, lateralization of the seizures, the need for intracranial monitoring, pathological findings, and the type and location of surgery did not appear to be associated with outcome.

CONCLUSIONS

This meta-analysis confirms the findings of other centers: ETLE surgical outcomes are less desirable than those for temporal lobe epilepsy. None of the factors studied in adults showed significant association with outcome. Contrary to some reports, shortening the duration of epilepsy by pursuing surgery as early as possible also does not appear to improve outcomes. The creation of standard protocols among epilepsy centers is needed to allow for a detailed evaluation of outcomes across different centers and, ultimately, to better assess the factors associated with improved outcomes.

Idiopathic childhood occipital epilepsy of Gastaut: a review and differentiation from migraine and other epilepsies

The purpose of this review is to provide guidance for appropriate diagnosis and management of idiopathic childhood occipital epilepsy of Gastaut. The typical clinical features are visual seizures that typically consist of brief elementary visual hallucinations, which are mainly multicolored and circular. Ictal blindness and deviation of the eyes are also common symptoms. The seizures are usually frequent and diurnal. The electroencephalography is the only investigation with abnormal results, showing occipital spikes and often occipital paroxysms demonstrating fixation-off sensitivity. Brain magnetic resonance imaging is used to exclude symptomatic occipital epilepsy. Patients usually respond well to antiepileptic medication and about two-thirds remit by the age of 16 years. Idiopathic childhood occipital epilepsy of Gastaut is frequently misdiagnosed as migraine with visual aura, acephalgic, or basilar migraine. Differentiation from symptomatic occipital epilepsy, particularly when children are otherwise normal, can be difficult. Most children need prophylactic antiepileptic medication.

Posterior cortex epilepsy: diagnostic considerations and surgical outcome

PURPOSE

To assess the role of various pre-surgical evaluations in posterior cortex epilepsy (PCE) and its surgical outcome.

METHODS

A retrospective analysis of clinical and laboratory data from 43 PCE patients referred for surgery was performed. The diagnosis was established by standard pre-surgical evaluation modalities including semiology, MRI, interictal and ictal scalp video-EEG as well as additional intracranial EEG monitoring in selected cases.

RESULTS

The 43 patients included 11 parietal lobe epilepsies, 13 occipital lobe epilepsies, and 19 patients with seizures originating from parieto-occipito-posterior temporal cortex. Thirty-three (76.7%) patients experienced at least one type of aura. Seventeen patients showed complex focal seizures, which were followed by secondarily generalized tonic-clonic seizures in seven of them; eighteen patients predominantly showed simple motor seizures (clonic seizures in 6, tonic seizures in 7, and versive seizures in 5). Long-term visual field deficits were observed in 8 patients. Other transient neurological deficits occurred in 7 patients. All patients received the follow-up study lasting 1-5 years, and achieved Engel's I in 26 cases, II in 5, III in 5, and IV-V in 7. Malformation of cortical development was diagnosed in 41.9% of our surgical population. No significant relationship was found between the diagnostic accuracy of any pre-surgical evaluating modality and surgical outcome in this series.

CONCLUSIONS

Surgical treatment is effective for PCE. Accurate localization of epileptogenic zone and eloquent cortex are two key factors for favorable outcome. None of the diagnostic modalities shows obvious predictive value for favorable surgical outcome.

A locus for bilateral occipital polymicrogyria maps to chromosome 6q16-q22

We describe the clinical, radiographic, and genetic features of a large consanguineous Moroccan family in which bilateral occipital polymicrogyria segregated as an autosomal recessive trait. Six affected members of the family had partial complex seizures often associated with behavioral abnormalities. On MRI, three patients had a thickened irregular cortex in the lateral occipital lobes with small gyri. A high-density genome-wide scan with 10,000 SNPs established linkage by homozygosity mapping to a 14-Mb region on chromosome 6q16-q22. Candidate genes by function (TUBE1, GRIK2, GPRC6A, GPR6, NR2E1, MICAL1, and MARCKS) in this locus were screened for mutations.

Surgical treatment of occipital lobe epilepsy

OBJECT

Occipital lobe epilepsy (OLE) accounts for a small percentage of extratemporal epilepsies and only few and mostly small patient series have been reported. Preoperative findings, surgical strategies, histopathological bases, and postoperative outcomes for OLE remain to be elucidated.

METHODS

A group of 54 patients with occipital lobe involvement were identified from a prospective epilepsy surgery database established in 1989. Medical charts, surgical reports, MR imaging, and histopathology data were reviewed, and patients with additional temporal and/or parietal involvement were categorized separately. Seizure outcome was classified according to the Engel classification scheme (Classes I-IV). Two patients were excluded due to incomplete data sets. Fifty-two patients with intractable epilepsy involving predominantly the occipital lobe were included in the study, comprising 17.8% of 292 patients undergoing operations for extratemporal epilepsies.

RESULTS

In nearly all cases (50 [96.2%] of 52), a structural lesion was visible on preoperative MR imaging. Of these cases, 29 (55.8%) had "pure" OLE with no temporal or parietal lobe involvement. Most patients (83%) had complex partial seizures, and 60% also had generalized seizures. All patients underwent occipital lesionectomies or topectomies; 9 patients (17.3%) underwent additional multiple subpial transections. Histopathology results revealed 9 cortical dysplasias (17.3%), 9 gangliogliomas (17.3%), 6 other tumors (11.5%), 13 vascular malformations (25%), and 15 glial scars (28.8%). Visual field deficits were present in 36.4% of patients preoperatively, and 42.4% had new or aggravated visual field deficits after surgery. After a mean follow-up of 80 months, 36 patients were seizure free (69.2% Engel Class I), 4 rarely had seizures (7.7% Engel Class II), 8 improved more than 75% (15.4% Engel Class III), and 4 had no significant improvement (7.7% Engel Class IV). Multifactorial logistic regression analysis revealed that early age at epilepsy manifestation (p = 0.031) and shorter epilepsy duration (p = 0.004) were predictive of better seizure control. All other clinical and surgical factors were not significant in predicting outcome.

CONCLUSIONS

Occipital lobe epilepsy is an infrequent but significant cause of extratemporal epilepsy. Satisfactory results (Engel Class I or II) were obtained in 77% of patients in our series. Postoperative visual field deficits occurred in a significant proportion of patients. In the modern MR imaging era, lesions should be investigated in patients with OLE and lesionectomies should be performed early for a better outcome.

The effectiveness of anticonvulsants in psychiatric disorders

Anticonvulsant drugs are widely used in psychiatric indications. These include mainly alcohol and benzodiazepine withdrawal syndromes, panic and anxiety disorders, dementia, schizophrenia, affective disorders, bipolar affective disorders in particular, and, to some extent, personality disorders, A further area in which neurology and psychiatry overlap is pain conditions, in which some anticonvulsants, and also typical psychiatric medications such as antidepressants, are helpful. From the beginning of their psychiatric use, anticonvulsants have also been used to ameliorate specific symptoms of psychiatric disorders independently of their causality and underlying illness, eg, aggression, and, more recently, cognitive impairment, as seen in affective disorders and schizophrenia. With new anticonvulsants currently under development, it is likely that their use in psychiatry will further increase, and that psychiatrists need to learn about their differential efficacy and safety profiles to the same extent as do neurologists.

Functional organization of human visual cortex in occipital polymicrogyria

Polymicrogyrias (PMG) are cortical malformations resulting from developmental abnormalities. In animal models PMG has been associated with abnormal anatomy, function, and organization. The purpose of this study was to describe the function and organization of human polymicrogyric cortex using functional magnetic resonance imaging. Three patients with epilepsy and bilateral parasagittal occipital polymicrogyri were studied. They all had normal vision as tested by Humphrey visual field perimetry. The functional organization of the visual cortex was reconstructed using phase-encoded retinotopic mapping analysis. This method sequentially stimulates each point in the visual field along the axes of a polar-coordinate system, thereby reconstructing the representation of the visual field on the cortex. We found normal cortical responses and organization of early visual areas (V1, V2, and V3/VP). The locations of these visual areas overlapped substantially with the PMG. In five out of six hemispheres the reconstructed primary visual cortex completely fell within polymicrogyric areas. Our results suggest that human polymicrogyric cortex is not only organized in a normal fashion, but is also actively involved in processing of visual information and contributes to normal visual perception.

Tailored resections in occipital lobe epilepsy surgery guided by monitoring with subdural electrodes: characteristics and outcome

PURPOSE

Occipital lobe epilepsy is uncommon in epilepsy surgery series and often difficult to assess due to rapid seizure propagation, misleading seizure semiology and confounding interictal epileptiform activity. Ictal recordings with surface electrodes may not define properly the seizure onset zone in surgical evaluation for intractable occipital epilepsy. Specially in dysplastic lesions, the extension of the epileptogenic zone is not well defined by neuroimaging techniques, therefore, implantation of intracranial electrodes is often indicated. In this study we present our experience with individually tailored resections of occipital lobe epileptic foci guided by monitoring with subdural electrodes.

METHODS

Data from interictal and ictal surface and intracranial recordings, neuroimaging, surgical treatment, pathology and outcome of seven patients are presented.

RESULTS

The most common seizure type (6/7 patients) was complex partial with temporal lobe semiology, five patients experienced visual auras as part of their complex partial seizures or as separate simple partial seizures. Two patients had seizures suggesting supplementary motor area involvement. One patient had temporal as well as frontal seizure propagation. Neuroimaging showed lesions in 6/7 patients. Pathological studies revealed cortical dysplasia and tumors as the most common causes. Intracranial recordings (6/7 patients) revealed focal onset in 2 patients, regional onset in 2, and diffuse onset in 2. Surgery was performed according to intracranial recordings restricting resections in cases with focal seizure onset (even in large dysplastic lesions) and performing wider resections in patients with regional or diffuse onset. Five of seven patients are seizure free after 12-55 months (mean 24.3). The two remaining patients may be classified as Engel 2b and 3a.

CONCLUSIONS

This series of occipital lobe epilepsy surgery shows that, even in patients with cortical dysplasias, restricted resections may have a good outcome and that intracranial monitoring is usually necessary in order to design an individually tailored resection.

Correlation of MRI and histopathology in epileptogenic parietal and occipital lobe lesions

INTRODUCTION

To analyze the diagnostic accuracy of MRI in patients undergoing parietal and occipital lobe epilepsy surgery.

METHODS

In a retrospective study, we analyzed MRI scans and neuropathology reports of 42 patients who had undergone resective epilepsy surgery in the parietal and occipital lobe between 1998 and 2003. We evaluated, whether lesions were precisely characterized by MRI and whether lesion characterization allowed to estimate postsurgical seizure outcome.

RESULTS

Within the categories epilepsy associated tumors, focal cortical dysplasias, vascular malformations, scarring, and others, MRI was concordant with histopathology in 36 of 42 (86%) lesions. Among the discordant lesions, one lesion was re-classified following MRI-histopathology synopsis, another two lesions represented new tumor entities (angiocentric neuroepithelial tumor, isomorphic astrocytoma) which have been described recently. Seizure freedom (Engel class I) one year following surgery was achieved in 25 patients (60%). Seizure outcome was different for lesion categories (Engel class I: epilepsy associated tumors, 62%; focal cortical dysplasias, 71%; vascular malformations, 75%; scarring, 40%), and was unchanged if no lesion was found on preoperative MRI.

CONCLUSION

If MRI and histopathology are discordant, not only the MRI findings may be debatable. MRI lesion detection is important, since chance of seizure freedom is low if no lesion is detected.

Use of multifocal visual evoked potential tests in the objective evaluation of the visual field in pediatric epilepsy surgery

OBJECT

To evaluate objectively the visual fields of patients with pediatric epilepsy who are uncooperative with perimetry and in whom postoperative visual field deficits are expected, the authors investigated the usefulness of the multifocal visual evoked potential (VEP) method.

METHODS

Normal waves in multifocal VEP were determined in 21 healthy children (21 eyes) 6 to 15 years of age (mean 11.4 years). Responses from eight sites in each child were divided into four quadrants (superior and inferior temporal and superior and inferior nasal). In each quadrant, two response waves were grouped and averaged. The peak latency and amplitude at approximately 100 msec were used for assessment. In three cases involving patients with epilepsy, multifocal VEP measurements were also recorded and compared with the peak latency and amplitude in the healthy children. In these children, no significant differences were observed in the peak latency of amplitude among four quadrants using one-way analysis of variance. In each patient, multifocal VEP tests showed abnormal waves in the quadrant corresponding to the lesion demonstrated in neuroradiological images. This result was useful in the treatment of choice and the postoperative evaluation.

CONCLUSIONS

Multifocal VEP tests can be useful in evaluating the visual field of children objectively. They can also be valuable in assessing preoperative visual field defects and revealing changes in the visual field after treatment.

Clinical features of patients with posterior cortex epilepsies and predictors of surgical outcome

PURPOSE

Posterior cortex epilepsies (PCEs) encompass a group of epilepsies originating from the occipital, parietal, or occipital border of the temporal lobe, or from any combination of these regions. When their seizures are refractory to pharmacologic treatment, these patients are usually referred for surgery. The aim of our study was to analyze clinical characteristics of all PCE patients referred for surgery from 1994 to 2003, and to search for predictors of surgical outcome.

METHODS

We performed a retrospective analysis of clinical and laboratory data from 81 consecutive refractory PCE patients referred for surgery. Surgical and nonsurgical groups of patients were compared, and detailed analyses of all variables of the surgical cases were performed in the search for predictors of seizure outcome.

RESULTS

Risk factors for PCEs included gliosis (34.56%), malformations of cortical development (33.33%), tumors (8.64%), brain trauma (3.70%), Sturge-Weber disease (4.93%), vascular malformations (3.70%), family history of epilepsy (3.70%), history of CNS infections (2.46%), and low IQ (2.46%). Of the 81 patients, 44 were submitted to surgery at the time of the completion of this study. Surgical treatment was highly effective in improving seizures (p<0.001) when compared with previous pharmacologic treatment alone. Twenty-eight (65.11%) patients became seizure free after surgery versus none in the nonsurgical group. Regarding outcome predictors, patients with shorter duration of epilepsy and those without neurologic abnormalities on clinical examination had higher chances of favorable evolution.

CONCLUSIONS

Surgical treatment is effective for the treatment of PCEs and superior to pharmacologic therapy alone. In our series, shorter duration of epilepsy and normal neurologic examination were the only independent variables that predicted better surgical outcome.

Occipital lobe epilepsy: clinical characteristics, surgical outcome, and role of diagnostic modalities

PURPOSE

To assess the role of various diagnostic modalities, to identify surgical prognostic factors and concordances with presurgical evaluations, and to characterize the clinical features of occipital lobe epilepsy (OLE), we studied 26 patients who were diagnosed as having OLE and underwent epilepsy surgery.

METHODS

Diagnoses were established by standard presurgical evaluations, which included magnetic resonance imaging (MRI), fluorodeoxyglucose-positron emission tomography (FDG-PET), ictal single-photon emission computed tomography (SPECT), scalp video-EEG monitoring, and intracranial EEG monitoring. After epilepsy surgery, patients were followed up for >2 years.

RESULTS

Sixteen (61.5%) of the 26 became seizure free after surgery, and another eight patients had a favorable outcome. Sixteen of the 26 patients experienced a type of visual aura (i.e., visual hallucination, visual illusion, blindness, or a field defect). Nine patients had both automotor seizures and secondary generalized tonic-clonic seizures at different times. Interictal EEG showed correctly localizing spikes in 10 of the 16 patients who became seizure free, and in three of the 10 non-seizure-free patients. MRI correctly localized the lesion in seven of these 16 seizure-free patients, and in three of the 10 non-seizure-free patients. FDG-PET correctly localized the lesion in eight of the 16 seizure-free patients, and in three of nine non-seizure-free patients. Ictal SPECT was performed in 19 patients and correctly localized the lesion in only three of 12 seizure-free patients, and in four of seven non-seizure-free patients. Ictal EEG correctly localized the lesion in 13 of the 16 seizure-free patients, and in five of the 10 non-seizure-free patients. No significant relation was found between the diagnostic accuracy of any modality and surgical outcome. The localizations of epileptogenic zones by these different diagnostic methods were complementary. The concordance of three or more modalities was significantly observed in seizure-free patients (p = 0.042). However, no definite relation was observed between the presence of lateralizing clinical seizure manifestation and surgical outcome (p = 0.108).

CONCLUSIONS

Some specific auras indicated an occipital epilepsy onset. Various diagnostic methods can be useful to diagnose OLE, and a greater concordance between presurgical evaluation modalities indicates a better surgical outcome.

Language dysfunction after frontal lobe partial seizures

Postictal language delay (PILD) patterns can lateralize temporal lobe complex partial seizures (CPS). The authors studied PILD in 24 patients with 118 frontal lobe CPS. Prolonged PILD occurred in only 7% of CPS confined to the dominant frontal lobe compared with 91% of CPS that started as frontal and spread to the dominant temporal lobe (p = 0.0001). Postictal language testing provides important information on frontal CPS localization and spread.

Long-term outcome after epilepsy surgery for focal cortical dysplasia

OBJECT

Reports of outcomes for surgical treatment of cortical dysplasia associated with epilepsy are conflicting due to the inclusion of patients with a wide range of malformations of cortical development. The authors report their experience and the long-term outcome for a subgroup of patients with the histopathological diagnosis of focal cortical dysplasia of Taylor.

METHODS

The records of 22 patients with focal cortical dysplasia of Taylor (15 with the balloon-cell type and seven with the nonballoon-cell type) were reviewed. There were 11 female and 11 male patients whose mean age was 26 +/- 17.6 years (mean +/- standard deviation [SD]) at surgery. The details of their epilepsy evaluation and resection were analyzed. Extent of resection was preoperatively planned using information obtained from long-term intracranial monitoring (15 patients) and/or more definitively determined by histopathologically proven clear margins during resection when feasible (12 patients). The mean duration of follow up was 6.3 +/- 5.1 years (mean +/- SD, range 0.5-15.6 years). Risk factors for epilepsy were trauma (seven patients) or meningoencephalitis (one patient); 14 patients (64%) had no obvious risk factors. The mean age at seizure onset was 9.2 years and the mean duration of their epilepsy was 16.1 +/- 9 years. In two patients there were no adverse findings on magnetic resonance (MR) imaging. In 15 patients (68%), the epileptogenic zone identified on long-term intracranial monitoring extended beyond the abnormality observed on MR images. Focal resection (lesion plus margins) was performed in 14 patients (64%), whereas eight (36%) underwent partial/tailored lobectomy. Two patients underwent multiple subpial transections in addition to partial lesionectomy because their lesions involved the sensorimotor cortex. In these two, functional MR imaging confirmed a normal functional anatomy despite the presence of the cortical dysplasia. Eleven (92%) of 12 patients who underwent resection guided by histopathologically proven clear margins and three (43%) of seven patients who underwent histopathologically proven subtotal resection have remained seizure free. Evidence of clear margins was significantly associated with an improved seizure outcome (p = 0.003). Postoperatively, expected deficits included nondisabling visual field defects, which occurred in three patients (14%), and transient sensorimotor deficits, which appeared in five (23%). Two patients had meningitis, which was successfully treated with antibiotics. Overall, 16 patients (73%) are either seizure free (13 patients), have rare nondisabling partial seizures (one patient), or had one seizure after their medication was changed (two patients). Thirteen patients (59%) have discontinued anticonvulsant medications or are being maintained on monotherapy. Of five patients (23%), two have had rare disabling seizures or significant reduction in their seizure frequency (three patients). One patient's seizures have remained the same.

CONCLUSIONS

Focal cortical dysplasias are a distinct subgroup of malformations of cortical development and have a favorable outcome after resection. The epileptogenic zone often extends beyond the abnormality found on neuroimaging. Resection of the epileptogenic zone guided by histopathologically proven clear margins is associated with an improved seizure outcome.

Subtraction SPECT Coregistered to MRI in Focal Malformations of Cortical Development: Localization of the Epileptogenic Zone in Epilepsy Surgery Candidates

PURPOSE

To determine the extent to which periictal subtraction single-photon emission computed tomography (SPECT) may improve detection and definition of the epileptogenic zone in patients with focal malformations of cortical development (MCDs).

METHODS

Subtraction SPECT coregistered to magnetic resonance (MR) images (SISCOM) were constructed for 22 consecutive patients with focal MCDs who underwent periictal SPECT injection (18 ictal and four postictal). In the 17 patients who had epilepsy surgery, concordance between the site of SISCOM localization and site of surgical resection was determined by coregistration of SISCOM images with postoperative MRIs.

RESULTS

SISCOM images were localizing in 19 (86%) patients, including eight of the 10 with nonlocalizing MRI. Concordance of SISCOM localization was 91% with MRI localization, 93% with scalp ictal EEG localization, and 100% with intracranial EEG localization. Eight patients whose SISCOM localization was concordant with the surgical resection site had lower postoperative seizure frequency scores (SFSs; p = 0.04) and greater postoperative improvement in SFSs (p = 0.05) than the nine patients whose SISCOM was either nonconcordant or nonlocalizing. On multiple regression analysis, a model combining SISCOM concordance with surgical resection site and extent of MRI lesion resection was predictive of postoperative SFS (R2 = 0.47; p = 0.03).

CONCLUSIONS

Periictal subtraction SPECT using the SISCOM technique provides useful information for seizure localization in patients with focal MCDs, even when MRI is nonlocalizing.

Temporo-occipital spikes: a typical EEG finding in Kabuki syndrome

Kabuki syndrome is a rare dysmorphogenic disorder. The central nervous system is often involved, and epilepsy is a common symptom. The diagnosis is clinical, and no typical electroencephalographic findings have thus far been reported. We have documented temporo-occipital spikes in sleep electroencephalogram in all our three Kabuki patients. The location of the spikes was similar in all cases although their occurrence varied from continuous spiking to single spikes. We suggest that temporo-occipital spikes are typical in Kabuki syndrome and discuss the possible cause of this finding.

Auras and other hallucinations: windows on the visual brain

Hallucinations in psychologically normal individuals provide a valuable route to studying the neural mechanisms of visual awareness. Migraine auras, epileptic auras and the hallucinations of Charles Bonnet Syndrome are examined in this context. Both similarities and striking differences in content are noted and the extent to which we are currently able to localize the source of these forms of endogenously driven visual awareness is discussed.

A detailed analysis of symptomatic posterior cortex seizure semiology in children younger than seven years

PURPOSE

To analyze the semiology of seizure onset and evolution in young children with posterior cortex epilepsy (PCE), compare this with adult reports, and assess age-related differences.

METHODS

We videotaped and analyzed 110 seizures from 18 patients with PCE, aged 3-81 months. All had a good prognosis after posterior epileptogenic zone removal. Ictal events were categorized by behavioral, consciousness, autonomic, and sensory features, as well as motor patterns, which included myoclonic, tonic, clonic, unclassified motor seizures, and epileptic spasm. A time-scaled data sheet was developed to record each epileptic event as onset, very early, early, or late manifestation.

RESULTS

Patients had a high seizure frequency with < or =100 attacks/day; one third of them showed a cluster tendency. The mean duration of seizures was 67 s. The most common seizure components were motor manifestations (with myoclonic and tonic seizures), but psychomotor (automotor), hypomotor attacks, and isolated auras also were frequently observed. Clinical seizure spread was frequent; auras and visual sensory signs were difficult to record in this age. Typical phenomena during seizures included behavioral changes, ictal vocalization, smile, flush, head nod, oculomotor features, and late-appearing oral automatisms, whereas hypermotor and secondarily generalized tonic-clonic seizures were not seen.

CONCLUSIONS

Our results suggest that PCE in infants and young children is very heterogeneous but shows important age-related features. Compared with adults, children with PCE have shorter but more frequent seizures; they rarely report aura or visual sensory signs, only sporadically develop hypermotor and secondarily generalized tonic-clonic seizures, whereas ictal smile, flush, head nod, and behavioral change are typical features at this age. Because of frequent subtle ictal phenomena, long-term video-EEG monitoring is a useful diagnostic tool with infants and young children with PCE.

Epilepsy surgery. Presurgical evaluation

The presurgical evaluation should result in a clear understanding of whether surgery can be undertaken and its associated risks and potential for benefit. The results of surgery are best when there is congruence in the seizure semiology, the irritative zone on interictal EEG, and the ictal onset zone with the epileptogenic lesion as defined on MRI and PET, and when there is a clear understanding of the ictal onset zone's relationship to eloquent cortex as defined by neuropsychologic evaluation, the intracarotid amobarbital test, and cortical functional mapping.

Visual activation positron emission tomography for presurgical evaluation of occipital lobe epilepsy--case report

A 14-year-old boy suffered from daily epileptic seizures originating from the left polymicrogyric occipital cortex. Visual activation positron emission tomography (PET) was used to map the function of the occipital cortex presurgically. Loss of visual function in the left occipital cortex was suggested by both visual activation PET and electrical cortical stimulation. Left occipital lobectomy resulted in a completely seizure-free status without deterioration in the visual function. Preoperative evaluation of the visual function in the epileptogenic occipital cortex by activation studies using PET or functional magnetic resonance imaging is the key to the successful surgical treatment of occipital lobe epilepsy.

Surgery for focal cortical dysplasia

Interest in surgery for focal cortical dysplasia has grown with the enhanced ability to detect these lesions preoperatively with modern imaging techniques. This article focuses on the surgical management of epilepsy associated with focal cortical dysplasia. The authors highlight the approaches practiced at Yale University, review their recent series of operative cases, and discuss a representative case example to illustrate important aspects of surgical strategy.

Diagnostic performance of [18F]FDG-PET and ictal [99mTc]-HMPAO SPECT in occipital lobe epilepsy

PURPOSE

We investigated whether interictal F-18 fluorodeoxyglucose positron emission tomography ([18F]FDG-PET) or ictal [99mTc]-HMPAO single-photon emission computed tomography (SPECT) was useful to find epileptogenic zones in occipital lobe epilepsy (OLE).

METHODS

We reviewed visually and quantified patterns of hypometabolism in interictal [18F]FDG-PET and those of hyperperfusion in ictal SPECT in 17 OLE patients (27 plus minus 6.8 years old; M/F, 10/7; injection time, 30 plus minus 17 s). OLE was diagnosed based on invasive electroencephalography, surgery, and postsurgical outcome (Engel class I in all at an average of 26 months after surgery).

RESULTS

Epileptogenic zones were correctly localized in nine (60%) of 15 patients by interictal [18F]FDG-PET, and asymmetric indices corroborated visual diagnosis. Epileptogenic hemispheres were correctly lateralized in 14 (93%) of 15 patients on [18F]FDG-PET. Epileptogenic hemispheres were correctly lateralized in 13 (76%) of 17 patients using ictal SPECT, but localization was possible in only five (29%) patients. Interictal [18F]FDG-PET was helpful in two of the patients who showed no abnormality on magnetic resonance imaging (MRI) and no possible localization with ictal SPECT.

CONCLUSIONS

In OLE, ictal SPECT was helpful in lateralization, but less helpful in localization. Interictal [18F]FDG-PET was helpful in localization or lateralization of epileptogenic zones, even in patients with ambiguous MRI or ictal SPECT findings.

Intractable pediatric epilepsy: presurgical evaluation

Epilepsy surgery in children requires a multidisciplinary approach. This section examines the role of scalp EEG, video-EEG monitoring, and intracranial EEG in the presurgical evaluation. Concepts central to understanding the basis for surgical treatment, such as the epileptogenic zone, the irritative zone, and the epileptogenic lesion, are discussed. An illustrative case then demonstrates application of the process in clinical practice. Neuroimaging and neuropsychological issues are not discussed herein; rather they are addressed elsewhere in this issue.

Benign childhood epileptic syndromes with occipital spikes: new classification proposed by the International League Against Epilepsy

In a recent proposal, the Commission on Classification and Terminology of the International League Against Epilepsy recognized early-onset childhood epilepsy with occipital spikes (Panayiotopoulos type), differentiating it from the only other type of childhood epilepsy with occipital spikes previously accepted: late-onset childhood epilepsy with occipital spikes (Gastaut type). The importance of this newly recognized syndrome of benign childhood partial seizures is that it is very common-only 2.4 times less frequent than benign rolandic epilepsy, and of equally excellent prognosis. It is characterized by a unique seizure type comprising a combination of autonomic and behavioral disturbances, vomiting, deviation of the eyes, and often with impairment of consciousness that can progress to convulsions. These commonly last for more than 3 minutes and in one quarter of cases for hours. One or more of these symptoms can predominate or be absent. Eyes can remain open without deviation, ictal vomiting might not occur, and autonomic and behavioral disturbances can predominate, particularly in the early stages of the ictus, and be missed in nocturnal seizures. Age at onset is 5 years, with a singular or a median of three seizures, which are predominantly nocturnal. Interictal electroencephalography (EEG) frequently shows occipital paroxysms or occipital spikes but one-fifth of the cases have only extraoccipital spikes on normal EEG. Treatment might not be needed. Panayiotopoulos syndrome, like rolandic epilepsy, needs recognition by the general pediatrician because of the invariably excellent prognosis and also because it can be misdiagnosed as an acute cerebral insult.

Surgery for malformations of cortical development causing epilepsy

Malformations of cortical development (MCD) are responsible for many cases of refractory epilepsy in adults and children. The results of surgical treatment are difficult to assess from the published literature. Judging from the limited number of adequately reported cases, approximately 40% of all cases of MCD treated surgically may be rendered seizure-free over a minimum 2-year follow-up period. This figure is the same for focal cortical dysplasia (FCD), the most common variety of MCD in surgical reports. In comparison with outcome for epilepsy associated with hippocampal sclerosis, this figure is low. Part of the difference may be artificial and related to limited reporting. Much of the difference is likely to relate to the complex underlying biology of MCD. Analysis of epileptogenesis in MCD has been undertaken. Different types of MCD have different sequelae. Some varieties are intrinsically epileptogenic; these include FCD and heterotopia. Although in most cases, the visualized MCD lies within the region of brain responsible for generating seizures (the epileptogenic zone), it may not constitute the entire epileptogenic zone in all cases. For polymicrogyria and schizencephaly in particular, the visualized abnormalities are probably not the most important component of the epileptogenic zone. There is evidence that the epileptogenic zone is spatially distributed and also, in some cases, temporally distributed. These findings may explain poor surgical outcome and the inadequacy of current presurgical evaluative methods. New preoperative techniques offer the opportunity of improved presurgical planning and selection of cases more likely to be rendered seizure-free by current surgical techniques. Of paramount importance is improved reporting. The establishment of a central registry may facilitate this aim. Specific recommendations are made for surgical strategies based on current experience and understanding.

Localizing value of epileptic visual auras

It is difficult to differentiate between seizures of occipital or temporal lobe origin in patients with focal epileptic seizures associated with visual aura. These are often suspected to originate from the visual cortex, which causes reluctance to propose resection as treatment for the affected patient. To determine the value of localizing different types of visual auras, we report on 20 patients experiencing visual aura from a series of 878 surgically treated patients suffering from intractable focal seizures. In all of these patients, a morphological abnormality was identified on MRI (n = 18) or cranial CT (n = 2). These abnormalities were shown to represent the morphological correlate of the epileptogenic zone in each case, as demonstrated by intracranial ictal EEG recordings and/or seizure freedom after focal resective surgery. Elementary hallucinations, illusions and visual loss were reported not only by all patients with occipital lobe epilepsy, but also by patients with occipitotemporal and anteromedial temporal seizure onset. Complex hallucinations never occurred in occipital lobe seizures but were present in the two other groups. The same correlation was found for concentric changes of visual field (tunnel vision), a newly described ictal phenomenon. We conclude that elementary hallucinations, illusions and visual loss, although typical for occipital lobe epilepsy, can also occur in anteromedial temporal or occipitotemporal seizures and are therefore not a discordant feature in presurgical evaluation of patients with suspected temporal lobe epilepsy. Complex hallucinations and tunnel vision, however, should be considered concordant only with the assumption of an anteromedial temporal or occipitotemporal seizure onset.