Biomedical subjects

F Gilliam

Publications and source records attributed to F Gilliam.

At least 19 recordsLinked to original sources

PubMed2007

Cortical abnormalities in epilepsy revealed by local EEG synchrony.

Abnormally strong functional linkage between cortical areas has been postulated to play a role in the pathogenesis of partial epilepsy. We explore the possibility that such linkages may be manifest in the interictal EEG apart from epileptiform disturbances or visually evident focal abnormalities. We analyzed samples of interictal intracranial EEG (ICEEG) recorded from subdural grids in nine patients with medically intractable partial epilepsy, measuring interelectrode synchrony using the mean phase coherence algorithm. This analysis revealed areas of elevated local synchrony, or "hypersynchrony" which had persistent spatiotemporal characteristics that were unique to each patient. Measuring local synchrony in a subdural grid results in a map of the cortical surface that provides information not visually apparent on either EEG or structural imaging. We explore the relationship of hypersynchronous areas to the clinical evidence of seizure localization in each case, and speculate that local hypersynchrony may be a marker of epileptogenic cortex, and may prove to be a valuable aid to clinical ICEEG interpretation.

Adolescent↗

PubMed2005

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.

Aged↗

PubMed2003

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.

Adult↗

PubMed2002

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.

Acetates↗

PubMed2001

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.

Anticonvulsants↗

PubMed2001

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.

Adult↗

PubMed2001

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.

Adult↗

PubMed2001

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.

Adolescent↗

PubMed2001

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.

Acetates↗

PubMed2000

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.

Adult↗

PubMed2000

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.

Adult↗

PubMed2000

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.

Adolescent↗

PubMed2000

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.

Adolescent↗

PubMed2000

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.

Adolescent↗

PubMed1999

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.

Adult↗

PubMed1999

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.

Adult↗

PubMed1999

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.

Adult↗

PubMed1999

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.

Adolescent↗