Depression but not seizure factors or quality of life predicts suicidality in epilepsy

The objective of this study was to determine prevalence and predictive risk factors of suicidality in a large sample of epilepsy outpatients. We prospectively examined 193 consecutive adult epilepsy outpatients for depression, including suicidal ideation. Demographic and epilepsy factors, medication toxicity and health-related quality of life were also evaluated. The prevalence of suicidal ideation within the past two weeks was 11.9%. Although medication toxicity, health-related quality of life and BDI scores were each associated with suicidal ideation in the bivariate analyses, only the BDI remained significant in the logistic regression analysis. About one-fourth of the subjects with suicidal ideation had no significant symptoms of depression. Recent thoughts of suicide are a common occurrence in the outpatient epilepsy clinic setting, but these are not predicted by gender, age, seizure factors, medication toxicity or self-perceived quality of life. Although depression is associated with suicidal ideation, about one-fourth of the suicidal subjects were euthymic or only mildly depressed.

Global assessment of nitrogen deposition effects on terrestrial plant diversity: a synthesis

Atmospheric nitrogen (N) deposition is a recognized threat to plant diversity in temperate and northern parts of Europe and North America. This paper assesses evidence from field experiments for N deposition effects and thresholds for terrestrial plant diversity protection across a latitudinal range of main categories of ecosystems, from arctic and boreal systems to tropical forests. Current thinking on the mechanisms of N deposition effects on plant diversity, the global distribution of G200 ecoregions, and current and future (2030) estimates of atmospheric N-deposition rates are then used to identify the risks to plant diversity in all major ecosystem types now and in the future. This synthesis paper clearly shows that N accumulation is the main driver of changes to species composition across the whole range of different ecosystem types by driving the competitive interactions that lead to composition change and/or making conditions unfavorable for some species. Other effects such as direct toxicity of nitrogen gases and aerosols, long-term negative effects of increased ammonium and ammonia availability, soil-mediated effects of acidification, and secondary stress and disturbance are more ecosystem- and site-specific and often play a supporting role. N deposition effects in mediterranean ecosystems have now been identified, leading to a first estimate of an effect threshold. Importantly, ecosystems thought of as not N limited, such as tropical and subtropical systems, may be more vulnerable in the regeneration phase, in situations where heterogeneity in N availability is reduced by atmospheric N deposition, on sandy soils, or in montane areas. Critical loads are effect thresholds for N deposition, and the critical load concept has helped European governments make progress toward reducing N loads on sensitive ecosystems. More needs to be done in Europe and North America, especially for the more sensitive ecosystem types, including several ecosystems of high conservation importance. The results of this assessment show that the vulnerable regions outside Europe and North America which have not received enough attention are ecoregions in eastern and southern Asia (China, India), an important part of the mediterranean ecoregion (California, southern Europe), and in the coming decades several subtropical and tropical parts of Latin America and Africa. Reductions in plant diversity by increased atmospheric N deposition may be more widespread than first thought, and more targeted studies are required in low background areas, especially in the G200 ecoregions.

Comorbidity between temporal lobe epilepsy and depression: a [18F]MPPF PET study

Brain and brainstem changes of serotoninergic 5-hydroxytryptophan (5-HT)(1A) receptor density have been reported in patients with major depressive disorder as well as in patients with temporal lobe epilepsy (TLE), using PET and the selective antagonist radiotracers [(11)C]WAY-100635 or [(18)F]FC-WAY. We used a distinct 5-HT(1A) antagonist, [(18)F]MPPF, whose binding potential depends on both receptor density and extracellular serotonin concentration, in 24 patients with drug-resistant TLE and MRI evidence of hippocampal sclerosis but without prior antidepressant exposure. Their Beck Depression Inventory (BDI-2) score ranged from 0 to 34, with nine patients having a score >11. We used a simplified reference tissue model, statistical parametric mapping and anatomical regions of interest (ROIs) to correlate parametric images of [(18)F]MPPF BP with the total BDI score and its four subclasses. The total BDI score, as well as symptoms of psychomotor anhedonia and negative cognition, correlated positively with [(18)F]MPPF BP in the raphe nuclei and in the insula contralateral to seizure onset, whereas somatic symptoms correlated positively with [(18)F]MPPF binding potential in the hippocampal/parahippocampal region ipsilateral to seizure onset, the left mid-cingulate gyrus and the inferior dorsolateral frontal cortex, bilaterally. We confirm an association of depressive symptoms in TLE patients with changes of the central serotoninergic pathways, in particular within the raphe nuclei, insula, cingulate gyrus and epileptogenic hippocampus. These changes are likely to reflect lower extracellular serotonin concentration in more depressed patients, with an upregulation of receptors a less likely alternative.

Epidemiological and medical aspects of epilepsy in the elderly

Both the incidence and prevalence of epilepsy are high among the elderly. Cerebrovascular disease is the most common underlying cause, although as many as 25-40% of new epilepsy cases in the elderly have no obvious underlying etiology. Status epilepticus appears to occur more frequently in individuals greater than 60 years, and the morbidity and mortality of status epilepticus are significantly greater in this age group. Elderly patients with seizures, particularly complex partial seizures, present differently than younger adults, which can lead to misdiagnosis. Post-ictal confusion may last as long as 1-2 weeks in an elderly patient, as opposed to minutes in younger individuals. Adverse events are similar in symptomatology, but are more common in elderly patients and occur at lower doses and plasma drug concentrations. Neuropsychiatric disorders, such as depression and anxiety, are common in elderly patients with epilepsy, although often under-diagnosed and inadequately treated. The risk of osteoporosis is high among elderly women taking antiepileptic drugs, which underscores the importance of assessing bone health and treatment in this group. Management of the older patient with epilepsy requires an understanding of the etiologies and the medical and psychological aspects unique to this age group.

Relationship between depression and intractability of seizures

Patients with epilepsy have a higher prevalence of depressive disorders than the general population, but the relationship between seizure rates and depression has not been adequately studied. We used the Beck Depression Inventory to evaluate depressive symptoms in 143 consecutive epilepsy patients from outpatient clinics. Patients who were seizure free more than 6 months were considered not intractable. Thirty-six percent were neither intractable nor depressed, 43% had intractable epilepsy and were not depressed, 10% had intractable epilepsy and were depressed, and 11% did not have intractable epilepsy and were depressed. Patients with epilepsy have a higher prevalence of depression than the general population, but the intractability of the seizure disorder does not seem to be an independent risk factor for the occurrence of depression. There is no relationship between the severity of depression and monthly seizure rate.

Modulation of cerebral GABA by topiramate, lamotrigine, and gabapentin in healthy adults

BACKGROUND

Anticonvulsant drugs have multiple mechanisms of action. Recent in vivo MRS studies suggest that cerebral gamma-aminobutyric acid (GABA) increases occur with the administration of certain anticonvulsants in humans.

OBJECTIVE

To investigate the effect of topiramate, gabapentin, and lamotrigine on cerebral GABA concentrations in healthy volunteers and correlate the GABA concentrations with serum drug levels.

METHODS

Seventeen healthy adults were randomly assigned to receive topiramate, gabapentin, and lamotrigine and underwent GABA measurements using a 4.1-T magnet from a 13.5-mL volume over the occipital region. GABA concentrations and serum levels were measured at 3 and 6 hours following administration of an acute single dose of one of the drugs. Thereafter, drugs were titrated over 4 weeks to target doses, with GABA measurements performed at 2 and 4 weeks.

RESULTS

Cerebral GABA concentrations rose 70% in the acute phase compared with baseline for topiramate. GABA rose 48% at 6 hours with gabapentin but not with lamotrigine. With long-term dosing and once target doses were achieved at 4 weeks, significant elevations in GABA were observed compared with baseline for all three drugs (topiramate 46%, gabapentin 25%, lamotrigine 25%).

CONCLUSION

This study demonstrates that single doses of topiramate and gabapentin increase cerebral GABA concentrations acutely (hours) in healthy individuals, but all drugs at clinically utilized doses increase cerebral GABA at 4 weeks. These results suggest that the mechanisms of action of anticonvulsant drugs are more complex and are likely to be multiple in nature.

Relationships among hippocampal volumetry, proton magnetic resonance spectroscopy, and verbal memory in temporal lobe epilepsy

PURPOSE

To examine the relationship between hippocampal volumes, 1H magnetic resonance spectroscopy (MRS)-identified hippocampal metabolic function, and verbal memory in patients with unilateral mesial temporal lobe epilepsy (MTLE).

METHODS

Hippocampal volumes, 1H MRS-derived hippocampal creatine to N-acetylaspartate (Cr/NAA), and verbal memory assessment were obtained preoperatively in 22 patients (six right, 16 left) with EEG-defined unilateral MTLE.

RESULTS

Left hippocampal volume correlated significantly with left hippocampal Cr/NAA (r=-0.549, p < 0.01), whereas right volume correlated significantly with right Cr/NAA (r=-0.478, p < 0.05). Verbal memory correlated significantly with left hippocampal Cr/NAA (r=-0.594, p < 0.01), but not with left hippocampal volume or right hippocampal measures.

CONCLUSIONS

Hippocampal volumes and 1H MRS-derived metabolite ratios are statistically related, but share only a small percentage of variance, suggesting separate but related pathophysiologic processes. Left hippocampal Cr/NAA appears to be more sensitive to verbal memory function than volumes.

Comparative cognitive effects of carbamazepine and gabapentin in healthy senior adults

PURPOSE

This study compared the cognitive effects of carbamazepine (CBZ) and gabapentin (GBP) in healthy senior adults by using a randomized, double-blind crossover design.

METHODS

Thirty-four senior adults were randomized to receive one of the two drugs followed by a 5-week treatment period. A 4-week washout phase preceded initiation of the second drug. Antiepileptic drugs (AEDs) were titrated to target doses of either CBZ (800 mg/day) or GBP (2,400 mg/day). Primary outcome measures were standardized neuropsychological tests of attention/vigilance, psychomotor speed, motor speed, verbal and visual memory, and the Profile of Mood State (POMS), yielding a total of 17 variables. Each subject received cognitive testing at predrug baseline, end of first drug phase, end of second drug phase, and 4 weeks after completion of the second drug phase.

RESULTS

Fifteen senior adults (mean age, 66.5 years; range, 59-76 years) completed the study. Seniors completing the study did not differ significantly from noncompleting seniors in terms of demographic features or baseline cognitive performances. Fifteen of the 19 seniors not completing the study dropped out while receiving CBZ. Adverse events were frequently reported for both AEDs, although they were more common for CBZ. Mean serum levels for the completers were within midrange clinical doses (CBZ, 6.8 microg/ml; GBP, 7.1 microg/ml). Significant differences between CBZ and GBP were found for only one of 11 cognitive variables, with better attention/vigilance for GBP, although the effect was modest. Performances on the nondrug average were significantly better on 45% of cognitive variables compared with CBZ and 36% compared with GBP. The overall pattern of means favored GBP over CBZ on 15 of 17 (p < 0.001), nondrug over CBZ on 17 of 17 (p < 0.0000), and nondrug over GBP on eight of 17 (NS).

CONCLUSIONS

Mild cognitive effects were found for both AEDs compared with the nondrug average condition. The magnitude of difference between the two AEDs across the cognitive variables was modest. Self-reported mood was not significantly affected by either AED. However, overall tolerability and side-effect profile of CBZ were poorer than those of GBP in senior adults at doses and titration rates reported in this study.

Verbal retention lateralizes patients with unilateral temporal lobe epilepsy and bilateral hippocampal atrophy

PURPOSE

To examine the lateralization utility of preoperative verbal retention in patients with and without bilateral hippocampal atrophy.

METHODS

The sample consisted of 74 patients with EEG-defined unilateral temporal lobe epilepsy (TLE) who had also undergone volumetric magnetic resonance imaging (MRI). Verbal retention was operationalized by the Logical Memory percentage retention subtest (LM%) of the Wechsler Memory Scale. Patients were divided into groups with (a) bilaterally normal hippocampal volumes, (b) unilateral atrophy, or (c) bilateral atrophy. Two different thresholds (empirically derived vs. normative) were used to lateralize on the basis of LM%. LM% lateralization was then examined by group using chi2, sensitivity, positive predictive values, and odds ratios. Analyses were also conducted separately in the subset of patients who were seizure free after surgery.

RESULTS

Mean LM% performance was significantly lower in patients with left versus right TLE in the subset with bilateral hippocampal atrophy (p = 0.018), but not in patients with a normal MRI (p = 0.918) or unilateral atrophy (p = 0.087). The odds of a correct lateralization by LM% increased from 1.67 in patients with normal MRI to 36.11 in patients with bilateral hippocampal atrophy. The power of a right and left lateralization prediction by LM% was 100% and 75%, respectively, in patients with bilateral hippocampal atrophy. Similar results were obtained when analysis was restricted to patients who were seizure free after surgery.

CONCLUSIONS

Preoperative verbal retention as measured by LM% may provide meaningful lateralization information in patients who are difficult to lateralize via MRI.

Health outcomes in persons with epilepsy

Epilepsy is a common disorder that effects millions of persons worldwide and costs billions of dollars for direct medical care. Despite the importance of epilepsy from a public health perspective, the physiological and psychosocial outcomes from epilepsy are incompletely understood and are in some ways controversial. The paroxysmal nature and the immense social stigma of the disorder have contributed to misunderstanding of its associated health outcomes. This article reviews the issues surrounding the assessment of health outcomes from the epilepsies and the interventions used to treat recurrent seizures.

Correlation of scalp EEG and 1H-MRS metabolic abnormalities in temporal lobe epilepsy

PURPOSE

To correlate the interictal spike field and region of seizure onset with the distribution of 1H-MRS abnormalities in temporal lobe epilepsy (TLE) and improve our understanding of the clinical significance of 1H-MRS abnormalities.

METHODS

Scalp electroencephalogram (EEG) monitoring and proton magnetic resonance spectroscopy (1H-MRS) results were correlated in 31 consecutive patients with TLE.

RESULTS

Lateralized 1H-MRS-based hippocampal abnormalities were recorded in 95% of the patients with unilateral interictal spikes, with a high degree of concordance for the lateralization side (90%). In 64% of the patients with normal or bilateral interictal EEG spikes, 1H-MRS provided lateralizing information. Bilateral 1H-MRS abnormalities, with or without lateralization, were 3 times more frequent than bitemporal EEG spikes. Anterior predominance of the 1H-MRS abnormalities was more frequent in patients with anterior temporal EEG spiking (50%), than in patients without this EEG distribution (18%). Similar association was noted between distribution of 1H-MRS abnormalities and region of EEG seizure onset.

CONCLUSIONS

Our results show a moderate level of concordance between the distribution of 1H-MRS and EEG abnormalities. 1H-MRS identifies abnormalities contralateral to the predominant seizure focus more often than does EEG and may provide lateralizing information in patients with nonlateralizing interictal EEG.

Occipitoparietal epilepsy, hippocampal atrophy, and congenital developmental abnormalities

PURPOSE

Diagnostic uncertainty may arise in patients with occipitoparietal epilepsy when there is neuroimaging evidence of a posterior quadrant lesion and coexistent hippocampal abnormalities ("dual pathology"). It is not known whether hippocampal atrophy (HA) in these patients results from seizure propagation to temporolimbic structures or whether it is part of the pathological process underlying the occipitoparietal epilepsy. Clarification of this issue may have a significant bearing on the management of these patients.

METHODS

We studied 20 patients with occipitoparietal epilepsy and neuroimaging or pathologic evidence of a congenital developmental abnormality. Normalized hippocampal volumes were obtained in all patients. The medical records and video-EEG recordings were analyzed to correlate the MRI findings with clinical data, seizure semiology, and EEG findings.

RESULTS

HA was found in seven patients (35%). Neuroimaging abnormalities concordant with the side of HA were seen in all cases. There was clinical or EEG evidence of temporal spread in 12 patients. There was no correlation between the presence of HA and temporal lobe spread. The only clinical factor associated with HA in this series was a younger age of seizure onset.

CONCLUSIONS

HA in patients with occipitoparietal epilepsy due to congenital developmental abnormalities is most likely to be a marker of a more widespread process related to a common pathogenesis during prenatal or perinatal development. HA in these patients is unlikely to be the result of secondary spread from an extrahippocampal focus. Surgical treatment should be tailored toward the primary epileptogenic zone rather the site of seizure spread.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

EEG spike detection with a Kohonen feature map

Artificial neural networks are widely used for pattern recognition tasks. For spike detection in electroencephalography (EEG), feedforward networks trained by the backpropagation algorithm are preferred by most authors. Opposed to this, we examined the off-line spike detection abilities of a Kohonen feature map (KFM), which is different from feedforward networks in certain aspects. The EEG data for the training set were obtained from patients with intractable partial epilepsies of mesiotemporal (n=2) or extratemporal (n=2) origin. For each patient the training set for the KFM included the same patterns of background activity and artifacts as well as the typical individual spike patterns. Three different-sized networks were examined (15 x 15 cells, 25 x 25 cells, and 60 x 60 cells in the Kohonen layer). To investigate the quality of spike detection the results obtained with the KFM were compared with the findings of two board-certified electroencephalographers. Application of a threshold based on the partial invariance of spike recognition against translation of the EEG provided an average sensitivity and selectivity of 80.2% at crossover threshold (71%-86%) depending on the networksize and noise. Multichannel EEG processing in real time will be available soon. In conclusion, pattern-based automated spike detection with a KFM is a promising approach in clinical epileptology and seems to be at least as accurate as other more-established methods of spike detection.

Adult myoclonic epilepsy: a distinct syndrome of idiopathic generalized epilepsy

The authors present 11 cases of idiopathic generalized epilepsy that began in adulthood at a mean age of 39 years. All patients had myoclonic jerks, five had absence seizures, and nine had infrequent generalized tonic-clonic seizures. A majority had a family history of seizures. EEG in all patients showed generalized epileptiform abnormalities, whereas neuroimaging and neurologic examination results were normal. This series appears to represent a previously undescribed idiopathic generalized epilepsy syndrome of adult myoclonic epilepsy.

Predictive value of MRI-identified mesial temporal sclerosis for surgical outcome in temporal lobe epilepsy: an intent-to-treat analysis

PURPOSE

Magnetic resonance imaging (MRI) accurately identifies mesial temporal sclerosis (MTS), but prediction of successful surgical outcome ranges from 62% to 96% in published studies. Prior investigations only used patients who had received anterior temporal lobectomy (ATL), potentially overestimating the predictive value of MRI-identified MTS (MRI-MTS).

METHODS

The authors performed an intent-to-treat analysis of 90 consecutive patients assessed for possible ATL, including 13 who did not undergo ATL because of inconclusive intracranial ictal EEG. Four (31%) of these 13 patients had unilateral mesial temporal abnormalities on their MRIs.

RESULTS

The positive predictive value of MRI-MTS for seizure cessation decreased from 0.69 to 0.63 after adjustment for these additional false positive results. Four previous studies had revealed a positive predictive value of 0.75 (0.72 after similar adjustment).

CONCLUSIONS

The authors conclude that the predictive value of MRI-MTS for outcome from ATL may be overestimated by small retrospective studies of highly selected postoperative patients.

Statistically driven identification of focal metabolic abnormalities in temporal lobe epilepsy with corrections for tissue heterogeneity using 1H spectroscopic imaging

1H spectroscopic imaging of N-acetyl-aspartate, creatine, and choline has proven to be a sensitive indicator for the lateralization of seizure foci in temporal lobe epilepsy. Previous studies have used right-left comparisons to identify the epileptogenic tissue assuming that alterations due to the disease process outweigh the effects of tissue heterogeneity. To evaluate the effectiveness of tissue heterogeneity corrected analyses, we evaluated three criteria for lateralization of the seizure focus: 1) a statistically driven method adjusted for tissue composition, 2) a single valued threshold, and 3) a single global index of the hippocampus. The statistically driven analysis lateralized all eight patients correctly, whereas the single threshold method incorrectly lateralized one case and the global index failed to identify a significant difference in two cases. These findings indicate that increased accuracy and sensitivity can be obtained by correcting for tissue heterogeneity when analyzing spectroscopy studies of temporal lobe epilepsy.

Cognitive correlates of 1H MRSI-detected hippocampal abnormalities in temporal lobe epilepsy

OBJECTIVES

To examine associations between 1H magnetic resonance spectroscopic imaging (1H MRSI)-detected hippocampal creatine to N-acetylaspartate (Cr/NAA) ratios and neuropsychological measures sensitive to mesial temporal lobe function.

BACKGROUND

The measurement of 1H MRSI-detected hippocampal metabolites has proved effective in determining extent and lateralization of neuronal damage. However, relationships between 1H MRSI-detected hippocampal metabolic abnormalities and specific areas of cognitive functioning have received limited attention compared to other studies using MRI volumetry or cerebral blood flow techniques.

METHODS

We analyzed right and left hippocampal Cr/NAA ratios in 46 adult mesial temporal lobe epilepsy patients (32 left, 14 right) by 1H MRSI at high magnetic field (4.1 T). We examined the relationship between the right and left Cr/NAA hippocampal ratios to measures of verbal and visual memory, intelligence, attention, visuoperception, and confrontation naming.

RESULTS

Measures of episodic verbal memory (n = 33) and visual confrontation naming (n = 46) were selectively associated with left hippocampal metabolic function (p<0.004), whereas neuronal function of the right hippocampal region was strongly associated with performance on a measure of facial recognition (n = 46; p<0.02).

CONCLUSIONS

This study shows that specific areas of cognitive function are related to hippocampal neuronal metabolic abnormalities as detected by spectroscopic imaging. The current study indicates that 1H MRSI offers a complimentary technique to structural imaging studies in the study of mesial temporal lobe epilepsy and may enhance understanding of the role of hippocampal function in complex cognitive systems.

Subjective versus objective memory change after temporal lobe epilepsy surgery

OBJECTIVE

To examine subjective versus objective memory change after anterior temporal lobectomy (ATL).

METHODS

A prospective, controlled study. Controls included 39 unoperated patients with intractable temporal lobe epilepsy (TLE) who were administered a series of cognitive and health-related quality of life measures at baseline and at 12-month follow-up intervals. The surgery sample included 65 patients with intractable, focal TLE who had undergone either a right or left ATL. These patients were tested preoperatively and at 6-month follow-up intervals. Subjective and objective memory change was quantified using a newly developed methodology to control for practice effect and regression to the mean.

RESULTS

Measures of subjective and objective memory change were not significantly related in the surgery sample. Prevalence of significant subjective memory decline 1 year after surgery ranged from 3 to 7%, whereas prevalence of significant objective memory decline ranged from 26 to 55%. Postoperative levels of emotional distress significantly predicted self-reported memory decline 1 year after ATL. Postoperative medication side effect and seizure outcome were also related significantly to subjective memory change in patients who had undergone left ATL.

CONCLUSIONS

Subjective and objective memory change after temporal lobectomy are not related. Complaints of significant memory decline after ATL are infrequent and may serve as a marker for depression or other mood disorder rather than organically based memory decline.

Predictive value of 1H MRSI for outcome in temporal lobectomy

OBJECTIVE

To investigate the predictive value of 1H MRSI for outcome in patients with mesial temporal lobe epilepsy (MTLE).

BACKGROUND

1H MRSI has been shown to be highly sensitive in the lateralization of temporal lob epilepsy.

METHODS

The authors analyzed the relationship between the 1H MRSI findings and surgical outcome in 40 consecutive patients who underwent temporal lobe surgery for MTLE. Outcome at a mean of 24 months (range 18 to 40 months) was classified as seizure free or not seizure free.

RESULTS

At follow-up, 78% of patients were seizure free. Correlations showed no predictive value for the creatine/N-acetylated compound (Cr/NA) ratio of the operated temporal lobe and outcome. However, a relationship was found between surgical failure and the Cr/NA ratio of the nonoperated temporal lobe and with a Cr/NA ratio in the nonoperated lobe above 1.21 in patients with bilateral abnormalities (p < 0.01).

CONCLUSIONS

Preoperative elevations in the Cr/NA ratio in the nonoperated temporal lobe or the presence of higher metabolic ratios contralateral to the proposed surgery are associated with surgical failure. The predictive value of 1H MRSI absolute metabolite concentrations for outcome in MTLE requires further investigation.

Cognitive consequences of coexisting temporal lobe developmental malformations and hippocampal sclerosis

OBJECTIVE

To characterize patterns of cognitive functioning in a well-defined group of patients with MRI-identified coexisting left temporal lobe developmental malformations (TLDM) and mesial temporal sclerosis (MTS), and to examine neuropsychological outcome in this dual-pathology group following epilepsy surgery.

METHODS

Cognitive functioning in patients with left TLDM and MTS (n = 15) was compared with patients with isolated left MTS (n = 40). TLDM and MTS were identified by high-quality MRI protocol. Patients were administered a battery of neuropsychology tests as part of their presurgical workup for possible epilepsy surgery. Unilateral temporal lobe resection was performed on 10 of the dual-pathology patients and 34 of the isolated MTS patients. Postoperative cognitive performance was also assessed.

RESULTS

Both groups displayed impairments in verbal and visual memory, language, and academic achievement. Performance on measures of psychometric intelligence, executive function, and attention were not impaired and were similar between groups. Presence of dual pathology was associated with a significantly less efficient verbal encoding strategy on the word list learning task. Postoperatively, declines were noted for both groups across tasks of verbal memory and language. Groups were not different significantly in terms of neuropsychological outcome after surgery.

CONCLUSION

Patients with coexisting TLDM and MTS have impaired cognitive functioning similar to MTS patients-in particular, with regard to episodic memory and language deficits. Temporal lobe resection produces similar cognitive changes in both groups.

Patient-oriented outcome assessment after temporal lobectomy for refractory epilepsy

OBJECTIVE

To determine patient-oriented outcome after anterior temporal lobectomy (ATL) for refractory epilepsy.

BACKGROUND

Health-related quality of life (HRQOL) is an important component of the assessment of outcome from epilepsy surgery, but prior controlled studies of the effect of surgery on HRQOL are inconclusive. Direct assessment of the effect of surgery on patient concerns of living with epilepsy has not been reported.

METHODS

We used reliable and valid instruments to compare HRQOL and patient concerns of 125 patients who had received an ATL more than than one year previously to a clinically similar group of 71 patients who were awaiting ATL. All patients were selected for surgery based on similar criteria. We also used bivariate correlation analysis and multivariate regression modeling to determine the association of traditional outcome variables with HRQOL.

RESULTS

Patients who had undergone ATL reported significantly less concern of living with epilepsy in 16 of 20 items of the EFA Concerns Index and better HRQOL in 8 of 11 scales of the Epilepsy Surgery Inventory-55. Regression analysis in the postoperative group demonstrated that mood status, employment, driving, and antiepileptic drug (AED) cessation, but not seizure-free status or IQ, were associated with better HRQOL.

CONCLUSIONS

Our findings support a positive affect of ATL on patient concerns and HRQOL in refractory temporal lobe epilepsy, although longitudinal studies are needed to corroborate these results. Mood, employment, driving ability, and AED use are important postoperative predictors of HRQOL.

Intraregional decline in case-fatality and hospital use after occlusive stroke in the southeastern United States

OBJECTIVE

To identify changes in mortality and hospital use among patients admitted for ischemic stroke in Alabama.

BACKGROUND

The decline in stroke mortality in the Southeast is greater than in other US regions. Whether this decline in a result of decreased incidence or improved case-fatality rates is unknown.

METHODS

We examined Medicare hospitalization data from approximately 625,000 beneficiaries and identified patients admitted for ischemic stroke between January 1992 and December 1994. The search was carried out using International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes pertinent to all diagnoses related to ischemic stroke. Data relevant to mortality and length of stay (LOS) were collected, and comparisons were made of the average case-fatality rate and LOS in each of the 3 years.

RESULTS

No significant difference was found in the incidence of ischemic stroke during the 3 years. The number of admissions was 4438 for 1992, 4124 for 1993, and 4762 for 1994. Conversely, the average LOS showed a significant decline, with values of 10.05, 9,36, and 8.72 days, respectively (P<.0003). A significant decline in mortality, with average case-fatality rates of 11.72%, 11.56%, and 9.71%, respectively (P<.003), was also found.

CONCLUSION

These data suggest that the decline in stroke mortality in the Southeast is because of improved patient survival after stroke, rather than decreased incidence. Although several factors may be contributing to the decreased case-fatality rates, improved care of hospitalized stroke patients is likely of primary importance. Additionally, decreased mortality associated with decreased LOS suggests more efficient hospital use.

Quantitative MRI in temporal lobe epilepsy: evidence for fornix atrophy

OBJECTIVE

To investigate whether the fornix and mamillary bodies, being part of the limbic system, are abnormal in patients with mesial temporal lobe epilepsy (MTLE).

BACKGROUND

The limbic system comprises the hippocampal formation, fornix, mamillary bodies, thalamus, and other integrated structures. This system is implicated in complex functions, including memory and emotion, and in diseases such as MTLE.

METHODS

The authors performed volumetric measurements of hippocampus, amygdala, fornix, and mamillary bodies in 50 patients with MTLE and compared the results with normal controls and patients with extratemporal lobe epilepsy.

RESULTS

Control (n = 17) measurements of the amygdala, hippocampus, and fornix revealed larger volumes of the right hemisphere structures (p < 0.001). Normalized fornix volumes revealed atrophy in 86% of studies concordant with hippocampal atrophy in all cases but one. Similarly, the mean hippocampal and fornix volumes for the group discriminated the epileptogenic temporal lobe (p < 0.001). Limbic volumes were normal in all patients with extratemporal lobe epilepsy.

CONCLUSIONS

Quantitative MRI findings support the concept that MTLE is not a process limited to the hippocampus but also involves other interrelated limbic system structures, in particular, the fornix.

Acute psychotic symptoms induced by topiramate

The incidence of psychosis during clinical trials of topiramate was 0.8%, not significantly different from the rate for placebo or reported rates of psychosis in patients with refractory epilepsy. We observed psychotic symptoms in five patients soon after initiation of topiramate therapy. We performed a retrospective chart review of the first 80 patients who began on topiramate after approval for clinical use, between January and April 1997. Symptoms suggestive of psychosis, including hallucinations and delusions, were sought for analysis. Cognitive effects such as psychomotor slowing, confusion, and somnolence were not included. Five patients developed definite psychotic symptoms 2 to 46 days after beginning topiramate. Dosages at symptom onset were 50-400 mg/day. Symptoms included paranoid delusions in four patients and auditory hallucinations in three. Symptoms of psychosis and other psychiatric symptoms resolved quickly with discontinuation of topiramate in three patients, dose reduction from 300 to 200 mg/day in one and with inpatient treatment and neuroleptics in another. One patient had a history of auditory hallucinations, one of aggressive and suicidal thoughts, but three had no significant psychiatric history. Physicians should be aware of the possibility of psychotic symptoms, even in patients without a previous psychiatric history, when prescribing topiramate. Symptoms resolve quickly with discontinuation.

Ambulatory EEG monitoring

Advances in computer technology offer increased capabilities for ambulatory EEG monitoring. The technical specifications of currently available ambulatory EEG machines reasonably approximate inpatient EEG equipment. However, the evolution of ambulatory EEG from 3-channel analog cassette recordings to reformatable 32-channel digital devices with computer-assisted spike and seizure detection raises several unresolved issues. Should patients with nondiagnostic routine EEG receive ambulatory EEG? Is ambulatory EEG as accurate for patients with unclear clinical diagnoses as inpatient video-EEG monitoring? If the diagnostic yield of ambulatory EEG is less than inpatient monitoring, do outpatient savings still make the technique cost-effective? This article reviews the development of ambulatory EEG and the investigations of its clinical utility. An evidence-based analysis explores the benefits and limitations of ambulatory EEG, and offers aspects of its use which require additional clinical research.

Temporal lobe developmental malformations and hippocampal sclerosis: epilepsy surgical outcome

BACKGROUND

Temporal lobe developmental malformations coexist with mesial temporal sclerosis in the form of dual pathology with a high frequency of bilateral amygdala or hippocampal abnormalities.

OBJECTIVE

The aim of this study was to correlate and compare the MRI findings and the surgical outcome in patients with temporal lobe developmental malformations (n = 20) and isolated mesial temporal sclerosis (n = 36).

METHODS

MRI-based normalized volumetry of the amygdala and hippocampal formation in patients with unilateral temporal lobe developmental malformations and isolated mesial temporal sclerosis who underwent temporal lobe resections was performed. Seizure outcome was compared between groups at follow-up.

RESULTS

The frequency of bilateral hippocampal or amygdala atrophy (p < 0.04) and combined hippocampal-amygdala atrophy (p < 0.02) was higher in patients with temporal lobe developmental malformations. Although no significant difference in postsurgical seizure-free status was found between the temporal lobe developmental malformations and isolated mesial temporal sclerosis groups (70% versus 91%), patients with temporal lobe developmental malformations and bilateral amygdala or hippocampal-amygdala atrophy had a significantly worse outcome (p < 0.02).

CONCLUSION

Bilateral hippocampal atrophy is frequent in patients with temporal lobe developmental malformations. However, it is the presence of bilateral amygdala or amygdalo-hippocampal atrophy that is associated with a higher risk of seizure recurrence.

Rasmussen's encephalitis with concomitant cortical dysplasia: the role of GluR3

The role of the glutamate receptor GluR3 in Rasmussen's encephalitis is actively under investigation. Autoimmune processes with this receptor as the target are currently theorized. We provide an additional case of pathologically proved Rasmussen's encephalitis (with concomitant cortical dysplasia) in the presence of antibodies against the GluR3 receptor.

Cognitive effects of topiramate, gabapentin, and lamotrigine in healthy young adults

OBJECTIVE

To study the acute and steady-state cognitive effects of three new antiepileptic drugs (AEDs): gabapentin, lamotrigine, and topiramate.

BACKGROUND

Several newer antiepileptic medications approved recently by the Food and Drug Administration are gaining attention as efficacious alternatives to established AEDs. Greater tolerability with fewer side effects are reported in some. However, the potential cognitive effects of these newer AEDs have received limited attention.

METHODS

Healthy young adults randomized to either of the three drugs were administered tests of attention, psychomotor speed, language, memory, and mood at baseline (predrug), acute single-dose period, and after 2 and 4 weeks on the drug.

RESULTS

Compared with baseline, the topiramate group had selective, statistically significant declines on measures of attention and word fluency at acute doses, whereas the other two AED groups had no performance changes. At the 2- and 4-week test periods, only the topiramate subjects continued to display neurocognitive effects from drug administration.

CONCLUSIONS

Results demonstrate potential acute and steady-state adverse cognitive effects for topiramate, whereas minimal effects were displayed for either gabapentin or lamotrigine in young healthy adults.

Significance of interictal temporal lobe delta activity for localization of the primary epileptogenic region

Because interictal temporal lobe delta activity (TLDA) has been described in 30 to 90% of patients with temporal lobe epilepsy (TLE) but has not been investigated in patients with extratemporal epilepsy, we sought to determine the localizing significance of TLDA. We compared the presurgical interictal scalp EEG results of 47 consecutive patients who received extratemporal resection (40 frontal and 7 parietal-occipital) for intractable epilepsy with 43 consecutive patients who received anterior temporal lobectomy. We defined lateralized TLDA as runs of lower than 4-Hz waveforms that were easily distinguished from the background rhythms and were maximal at electrodes T4, F8, and T6 or T3, F7, and T5. The lateralized TLDA was subcategorized as temporal intermittent rhythmic delta activity (TIRDA) or temporal intermittent polymorphic delta activity (TIPDA). A chi-square test was used to determine the association of the lobe of the epileptogenic zone with TIRDA and TIPDA. We found TIRDA in 12 (28%) and TIPDA in 8 (19%) patients in the temporal lobe group, and TIRDA in 2 (4%) and TIPDA in 9 (19%) patients in the extratemporal group. TIRDA was strongly associated with TLE (p < 0.003), whereas TIPDA occurred at an equal rate in both groups. Similar to anterior temporal epilepsy, lateralized TIPDA is present in up to 20% of patients with extratemporal epilepsy. The presence of TIRDA strongly suggests TLE but may infrequently occur in extratemporal epilepsy. Caution should be used when using lateralized TLDA as a presurgical localizing finding.

Amygdala atrophy and seizure outcome after temporal lobe epilepsy surgery

Surgical outcome in hippocampal atrophy (n = 44) and amygdalohippocampal atrophy (n = 14) were compared. Hippocampal atrophy had better seizure-free outcome than amygdalohippocampal atrophy (80% versus 50%, p = 0.043). Severity of hippocampal atrophy correlated with duration of epilepsy in patients with hippocampal atrophy (r = 0.4, p = 0.007), but not in those with amygdalohippocampal atrophy, suggesting that these two groups may have a different pathogenesis.

An active-control trial of lamotrigine monotherapy for partial seizures

OBJECTIVE

We report the results of a double-blind, double-dummy, active-control study designed to evaluate the efficacy and safety of lamotrigine (LTG) administered as monotherapy to adult outpatients with partial seizures.

BACKGROUND

The effectiveness of LTG as add-on therapy for partial seizures in adults has previously been established.

METHODS

After an 8-week baseline during which patients continued their baseline antiepileptic drug (carbamazepine or phenytoin monotherapy), 156 patients were randomly assigned to receive increasing doses of LTG (target 250 mg b.i.d.) or valproic acid (VPA; target low dose of 500 mg b.i.d.) during the first 4 weeks of an 8-week transition period. Carbamazepine or phenytoin was withdrawn over the next 4 weeks; then patients entered a 12-week monotherapy period. Study drug treatment was discontinued in patients who met predetermined escape criteria for seizure worsening.

RESULTS

More patients receiving LTG were successfully maintained on monotherapy compared with patients receiving VPA (56% versus 20%; p < 0.001). The time to meet the escape criteria was also significantly longer in LTG-treated patients (median = 168 days) than in VPA-treated patients (median = 57 days; p = 0.001). The incidence of adverse events during the monotherapy period was lower than during the transition period. Four LTG patients and five VPA patients reported serious adverse events. Two of those patients experienced a rash that led to withdrawal soon after adding LTG to carbamazepine.

CONCLUSIONS

We conclude that LTG is effective and well tolerated when administered as monotherapy in adult patients with partial seizures.

Topiramate increases cerebral GABA in healthy humans

Topiramate (TOP) is a novel anticonvulsant drug with multiple mechanisms of action used in the treatment of epilepsy. Measurements of cerebral GABA were obtained in six controls using 1H MRS at baseline and at 3 and 6 hours following the administration of 3 mg/kg of TOP. Brain GABA concentrations rose by 72% at 3 hours and by 64% at 6 hours compared with baseline (p < 0.004). This study demonstrates that TOP significantly increases human cerebral GABA concentrations in healthy individuals.

Relative utility of 1H spectroscopic imaging and hippocampal volumetry in the lateralization of mesial temporal lobe epilepsy

OBJECTIVES

To determine the relative utility of 1H MRSI and hippocampal volumetry for the lateralization of mesial temporal lobe epilepsy (MTLE) in patients with intractable epilepsy.

BACKGROUND

MTLE is the most common partial-onset seizure disorder in patients undergoing temporal lobe epilepsy surgery. MR volumetry and spectroscopy are reliable preoperative imaging techniques for the lateralization of MTLE.

METHODS

We analyzed the 1H MRSI and hippocampal formation volumes preoperatively in 30 consecutive patients who had undergone temporal lobectomy.

RESULTS

Volumetry correctly lateralized the side of surgery in 93% of patients and 1H MRSI did so in 97% of patients. Incorrect lateralization occurred by volumetry in two patients and by 1H MRSI in one patient. Concordance between all MRI modalities was 73%. Pearson's analysis revealed no correlation between the degree of hippocampal volume loss and the creatine-to-N-acetylated-compounds ratio.

CONCLUSIONS

Volumetry and 1H MRSI correctly lateralized most patients with MTLE and complement each other in final lateralization. The lack of correlation between the severity of volume loss and the degree of metabolic disturbance suggests that the techniques examine distinct pathophysiologic processes in MTLE.

Incidence of spikes and paroxysmal rhythmic events in overnight ambulatory computer-assisted EEGs of normal subjects: a multicenter study

The incidences of spikes and paroxysmal rhythmic events (PREs) in 10-h overnight EEGs of normal adult volunteers (n=135) were studied at 11 sites with a computer-assisted ambulatory EEG monitoring system with automatic spike and PRE detection. Spikes were evident in the overnight EEG of 1 subject (0.7%), and PREs were apparent in the overnight EEG of the same subject (0.7%). The incidences of spikes of 24 other subjects with a history of migraine and/or a family history of epilepsy were 12.5 and 13.3%, respectively. The overnight EEGs of these subjects were significantly more likely to show spikes than the overnight EEGs of subjects without migraine or a family history of epilepsy.

Volumetric MRI of the limbic system: anatomic determinants

The limbic system comprises the hippocampal formation, fornix, mamillary bodies, thalamus, and other integrated structures. It is involved in complex functions including memory and emotion and in diseases such as temporal lobe epilepsy. Volume measurements of the amygdala and hippocampus have been used reliably to study patients with temporal lobe epilepsy but have not extended to other limbic structures. We performed volume measurements of hippocampus, amygdala, fornix and mamillary bodies in healthy individuals. Measurements of the amygdala, hippocampus, fornix and mamillary bodies revealed significant differences in volume between right and left sides (P < 0.001). The intraclass coefficient of variation for measurements was high for all structures except the mamillary bodies. Qualitative image assessment of the same structures revealed no asymmetries between the hemispheres. This technique can be applied to the study of disorders affecting the limbic system.

Temporal lobe developmental malformations and epilepsy: dual pathology and bilateral hippocampal abnormalities

Temporal lobe developmental malformations (TLDM) with focal cortical dysplasia and balloon cells may coexist with mesial temporal sclerosis. The true incidence of this dual pathology is unknown. Our aim was to assess the frequency of amygdala (AM)-hippocampal abnormality in a homogeneous population with this specific developmental malformation. MRI-based volumetry of the AM and hippocampal formation (HF) in 30 patients with unilateral TLDM and intractable partial epilepsy was performed. A volume normalization process defined a normal range of HF and AM volumes in control subjects, and enabled the detection of bilateral volume loss. Normalized volumes detected HF atrophy in 26 patients (nine unilateral and 17 bilateral) and AM atrophy in 18 patients (three unilateral and 15 bilateral). Visual analysis detected unilateral HF abnormality in 21 patients and bilateral abnormality in two. When compared with a group of patients with temporal lobe epilepsy and pure hippocampal sclerosis (N = 92), where volumetry revealed bilateral HF atrophy in 18%, a significant difference in the frequency of bilateral HF atrophy was found (p < 0.0001). Dual pathology is frequent in patients with TLDM (87%), and the AM-HF abnormality is often bilateral (57%). Our data suggest that more widespread and potentially epileptogenic lesions coexist with visibly detectable unilateral TLDM. This has implications for the selection of patients for temporal lobe surgery and may influence surgical strategies.

Congenital porencephaly: MR features and relationship to hippocampal sclerosis

PURPOSE

We determined the frequency of amygdalar-hippocampal atrophy in patients with congenital porencephaly-related seizure disorders to ascertain whether specific MR features of the porencephaly correlate with amygdalar-hippocampal atrophy and epilepsy.

METHODS

We studied brain MR images of 22 patients with congenital porencephaly and measured the volume of the amygdala, the hippocampal formation, and the porencephalic cyst. We then compared imaging features with seizure symptoms.

RESULTS

Porencephaly was unilateral in 20 patients and bilateral in two. Eighteen patients had cortical or subcortical cavitation and four had encephaloclastic changes (noncircumscribed parenchymal destruction associated with cystic components). The porencephaly was located in the middle cerebral artery territory in 12 patients, in the posterior cerebral artery in four, in the internal carotid artery in two, and in multiple vessels in four. The volume of the porencephalic cyst ranged from 1% to 32% of total intracranial volume (mean, 11%). Volumetry detected atrophy of the hippocampal formation in 21 cases (11 unilateral, 10 bilateral) and atrophy of the amygdala in 12 (nine unilateral, three bilateral). No correlation was found between size or location of the porencephaly and degree of hippocampal atrophy. Seizure symptoms correlated with mesial temporal origin but not with cyst location.

CONCLUSION

Amygdalar-hippocampal atrophy often coexists with congenital porencephaly (95%), and the atrophy may be bilateral despite unilateral cysts. Hippocampal structures should be carefully assessed in patients with porencephaly-related seizures.

Association of combined MRI, interictal EEG, and ictal EEG results with outcome and pathology after temporal lobectomy

PURPOSE

Magnetic resonance imaging, interictal scalp EEG, and ictal scalp EEG each have been shown to localize the primary epileptic region in most patients with mesial-basal temporal lobe epilepsy (MBTLE), but the association of surgical outcome and pathology with each combination of these test results is not known.

METHODS

We reviewed the MRI, interictal scalp EEG, and ictal scalp EEG results of 90 consecutive patients with MBTLE. Twelve patients were excluded from the analysis because inconclusive bitemporal intracranial EEG results precluded anterior temporal lobectomy (ATL); none had concordant MRI and interictal scalp EEG results. We compared all combinations of presurgical MRI, interictal EEG, and ictal EEG results to seizure outcome and tissue pathology in the 78 patients who underwent an ATL.

RESULTS

Forty-eight (61%) patients had concordant lateralized MRI and interictal EEG temporal lobe abnormalities, with no discordant ictal EEG results; 77% of these patients were seizure-free after ATL. Concordance of MRI and interictal EEG abnormalities correlated with seizure cessation (p < 0.05), compared to all combinations with discordant or nonlateralizing MRI and interictal EEG results. Mesial temporal sclerosis (MTS) was confirmed pathologically in about 80% of both groups (p = 0.5). Outcome in patients with concordant MRI and ictal EEG with nonlateralizing interictal EEG was significantly worse than combinations with concordant MRI and interictal EEG (p < 0.02).

CONCLUSIONS

Compared to other combinations of test results, concordance of MRI and interictal EEG is most closely associated with surgical outcome in MBTLE. However, most selected patients have pathologic confirmation of MTS regardless of test results or outcome. This information may be useful for planning the presurgical evaluation of patients with medically intractable MBTLE.

Congenital porencephaly and hippocampal sclerosis. Clinical features and epileptic spectrum

We studied clinical features and seizure localization in 14 patients with porencephaly and intractable seizures. Perinatal complications were present in nine patients, childhood febrile convulsions in two, congenital hemiparesis in 12, and intellectual impairment in seven. Ten patients had psychoparetic complex partial seizures (CPS), three had sensorimotor simple partial seizures, and one had generalized tonic-clonic seizures. Surface EEG showed temporal onset in nine patients (one bitemporal) and extratemporal onset in four. MRI showed porencephaly in the distribution of the middle cerebral artery in eight patients, posterior cerebral in three, internal carotid in one, and multiple vessels in two. MR-based volumetry revealed hippocampal formation atrophy in 13 patients (eight unilateral and five bilateral) and amygdalar atrophy in 10 patients (nine unilateral and one bilateral). Hippocampal formation atrophy was concordant with CPS semiology in 10 patients (71%) and with EEG temporal localization in nine patients. Two patients had pathologic confirmation of mesial temporal sclerosis and were seizure free after temporal lobectomy. We conclude that mesial temporal sclerosis often coexists with porencephaly and is the likely seizure focus in the presence of concordant electroclinical data. This recognition implies that effective surgical intervention can be offered to certain patients with porencephaly-related seizure disorders. The dual pathology and association with perinatal cerebral vascular occlusion suggest a common ischemic pathogenesis.

Multimodality MRI in mesial temporal sclerosis: relative sensitivity and specificity

Our objectives were to determine the relative sensitivity and specificity of different MRI sequences and analysis techniques for the detection of mesial temporal sclerosis (MTS). Mesial temporal sclerosis is the most common pathologic finding in patients undergoing temporal lobe epilepsy surgery. Magnetic resonance imaging is the most reliable preoperative imaging technique for the detection of MTS. We analyzed the abnormalities in preoperative MRIs of 44 consecutive patients who had undergone temporal lobectomy and who had pathologic confirmation of MTS. Techniques included inversion recovery (IR); T1-weighted, volume-acquired images; hippocampal T2 relaxometry (HT2); volumetric assessment; and visual analysis. Sensitivity was 86% with IR, 90% with T1-weighted qualitative visual analysis, and 97% with quantitative volumetry. Pathologic prolongation of HT2 (> 2 SD of normal) was present in 79%. Analysis of variance showed statistically significant differences in sensitivity between HT2, volumetric measurements (p < 0.01), and qualitative visual atrophy (p < 0.05). Concordance between all MRI modalities was 68%. Inversion recovery and qualitative analysis lateralized the side of surgery in 93%. The combination of IR and T1-weighted images correctly identify MTS in most patients. Hippocampal volumetry provided localization in an additional small number of patients.

Intrinsic epileptogenesis of hypothalamic hamartomas in gelastic epilepsy

Hypothalamic hamartomas and gelastic seizures are often associated with cognitive deterioration, behavioral problems, and poor response to anticonvulsant treatment or cortical resections. The origin and pathophysiology of the epileptic attacks are obscure. We investigated 3 patients with this syndrome and frequent gelastic seizures. Ictal single-photon emission computed tomography performed during typical gelastic seizures demonstrated hyperperfusion in the hamartomas, hypothalamic region, and thalamus without cortical or cerebellar hyperperfusion. Electroencephalographic recordings with depth electrodes implanted in the hamartoma demonstrated focal seizure origin from the hamartoma in 1 patient. Electrical stimulation studies reproduced the typical gelastic events. Stereotactic radiofrequency lesioning of the hamartoma resulted in seizure remission without complications 20 months after surgery. The functional imaging findings, electrophysiological data, and results of radiofrequency surgery indicate that epileptic seizures in this syndrome originate and propagate from the hypothalamic hamartoma and adjacent structures.

Supplementary sensorimotor area epilepsy. Seizure localization, cortical propagation and subcortical activation pathways using ictal SPECT

We studied clinical signs, EEGs and ictal cerebral blood flow by single-photon emission computed tomography (SPECT) in eight patients with intractable supplementary sensorimotor area (SSMA) seizures. SPECT scans were performed after injection of the regional cerebral blood flow tracer [99mTc]HMPAO (hexametylpropylene amine oxime) early in the ictal phase (2-5 s after seizure onset). Ictal SPECT demonstrated unilateral predominance of hyper-perfusion of the SSMA in all patients, concordant with either lateralizing clinical signs, lateralization of ictal scalp EEG or with the site of ictal onset of seizures, obtained from intracranial electrodes. Two distinctive cortical blood-flow propagation patterns were identified in SSMA seizures. The type I pattern consisted of primary involvement of the ipsilateral SSMA and dorsal premotor and motor cortex. The type II pattern consisted of bilateral but asymmetric mesial frontal propagation. Ictal contraversive head and eye movements were associated with a type I propagation pattern (P < 0.03). Activation of subcortical structures led to variable hyper-perfusion of the basal ganglia and thalamus. Contralateral cerebellar hyperperfusion was observed in all cases. We conclude that ictal SPECT is a useful method for seizure localization in patients with SSMA epilepsy. The observed heterogeneity of clinical features in SSMA epilepsy correlates with propagation to, and activation of, specific cortical structures, and is consistent with known anatomical interconnections between the SSMA, ipsilateral cortical and transcallosal cortical structures.

Epilepsy surgery outcome: comprehensive assessment in children

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

Proton spectroscopic imaging at 4.1 tesla in patients with malformations of cortical development and epilepsy

We used proton magnetic resonance spectroscopic imaging (MRSI) at 4.1 tesla in patients with malformations of cortical development (MCDs) and epilepsy. We compared the spectroscopic results with normative data using 2 SDs (95% confidence) above normal values for detection of significant abnormalities for creatine-N-acetylated compounds (Cr/NA) ratio and choline-N-acetylated compounds (Cho/NA). The results were correlated with clinical, EEG, and histologic findings. Patients with focal cortical dysplasia showed significant metabolic abnormalities in correspondence with the structural lesions, whereas patients with heterotopia and polymicrogyria demonstrated no subcortical MRSI abnormalities. Significant correlations were found between the metabolic abnormalities and the frequency of seizures but not with the degree of interictal EEG discharges. Quantitative neuronal and glial cell counts revealed no statistically significant correlation between cell loss and the abnormal metabolic ratios in those who underwent surgery. These preliminary findings suggest that MRSI-based metabolic abnormalities in patients with MCDs are variable and are likely to be associated with complex cellular mechanisms involving the regulation of NA, total Cr content, and Cho.

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

PURPOSE

Cortical developmental malformations (CDM) are increasingly recognized in association with epilepsy. We describe 10 patients (age range 14-35 years) with symptomatic occipital lobe epilepsy and CDM.

METHODS

Neurologic, neuroophthalmologic and electrophysiologic studies were performed. Patients had MRI, SPECT, and in some cases intracranial EEG investigators.

RESULTS

Mean age of seizure onset was 8 years. We noted strong correlations between the presence of visual auras, the scalp EEG pattern, and the subtype of underlying pathology. Magnetic resonance imaging (MRI) showed CDM in all patients, with polymicrogyria and focal dysplasia being the most frequent malformations. Despite the presence of occipital lobe structural malformations in all patients, visual field deficits were present in only 2. Those who underwent cortical resections were seizure-free or showed major improvement at a mean follow-up of 3.5 years.

CONCLUSIONS

Intracranial stimulation studies and the low frequency of pre- and postoperative deficits suggest that some degree of cortical visual reorganization may occur in patients with occipital lobe malformations. Occipital lobe CDM should be sought as a cause of symptomatic occipital lobe epilepsy even though they may become symptomatic after childhood.