Browsing by Subject "Epilepsy"
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Item Affective priming following unilateral temporal lobectomy : the role of the amygdala(2012-08) Worthy, Emily Luther; Beevers, Chris G.; Tucker, David M., 1953-; Schnyer, David; Shen, Jason; Maddox, ToddThe way that emotions are processed in the brain has been widely debated. The two leading hypotheses are the cognitive appraisal viewpoint (Lazarus, 1982) and the affective primacy hypothesis (Zajonc, 1980). The former argues that higher cortical structures are needed to evaluate affective stimuli whereas the latter asserts that humans can use information only processed at the subcortical level to influence behavior. The current study tested the presence of this subcortical pathway by using an affective priming task developed by Murphy and Zajonc (1993). Happy and angry faces were presented for 4 ms before the presentation of a neutral stimulus (Chinese Ideograph) that participants were asked to rate based on how much they liked each one. Individuals do not report conscious awareness of primes presented at this suboptimal speed. In a young adult sample, participants rated ideographs preceded by happy primes significantly higher than those preceded by angry primes. Also, the priming effect was only observed in participants who reported a high positive mood. Next, when primes were presented in the left or right hemifield priming was only found in the right hemifield, and was driven by increased ratings for ideographs preceded by happy primes. Patients with epilepsy who have undergone a temporal lobectomy provide a unique opportunity to study emotional processing. In this procedure, not only is the seizure focus (typically the hippocampus) removed, but the amygdala and surrounding areas of the mesial temporal lobe are removed as well. Nine patients post right temporal lobectomy and three patients post left temporal lobectomy completed the study and did not show an effect of priming. However, 21 pre-surgical epilepsy patients were found to give higher liking ratings to ideographs preceded by angry primes as compared to those preceded by happy primes. Overall, these results support the affective primacy hypothesis however they also suggest that patients with temporal lobe dysfunction may process emotional stimuli differentially from controls. In this population, ideographs preceded by angry primes were rated as more liked than those preceded by happy primes. Directions for future studies to clarify the role of the amygdala in emotional processing are discussed.Item Cognitive-communication deficits caused by topiramate : a summary of implications relevant to SLPs(2011-05) Chamberlain, Ashley Elizabeth; Harris, Joyce L.; Granof, Dena H.This report provides an overview of the adverse effects of the antiepileptic drug topiramate. Specifically, it evaluates the negative cognitive-communication effects of topiramate on individuals with epilepsy and postulates that treating these deficits is within the scope of practice of speech-language pathologists. It begins with a discussion on epilepsy, description of seizures, and the mechanism of action for antiepileptic drugs. It then provides an overview of cognitive communication deficits caused by antiepileptic drugs, including: memory problems, impairments in attention, and executive dysfunction. The final section provides an outline of potentially beneficial treatments a speech-language pathologist may provide to patients experiencing adverse effects from topiramate and how continued research can expand this area of practice.Item EEG signal analysis for seizure detection(Texas Tech University, 1996-05) Qin, DongyingBiological tissue obeys Ohm's law for small current densities [6]. Bioimpedance can be measured with four electrodes: two for current injection and two for voltage measurement. The magnitude of the impedance is given by the ratio of the magnitude of the measured voltage and the magnitude of the injected current. There seems to be a slow increase in measured impedance several minutes prior to the onset of seizure activity. This result may be caused by ionic (Ca^^) shifts prior to seizure formulation [13]. However, whether the result is common for most epilepsy patients is still unknown. Besides, there are also some difficulties in determining a suitable warning threshold, and the procedures for bioimpedance measurement are more complicated than that for an EEG [13]. An EEG is the recording of electrical cerebral potentials [6]. AU chemical and physical processes that take place in living cells produce electrical energy. The energy can be recognized by changes in potential of the cell membrane [11]. The potential of one cell is very small, but when a larger group of cells acts simultaneously, the potential is higher and can be recorded with suitable amplification. Many techniques have been developed for EEG signal analysis. Some techniques have been used for seizure detection or prediction, but there have been no conclusive findings. In this thesis, EEG analysis is used as a tool for seizure detection or prediction. Several different signal analysis techniques are examined. The objective is to determine which technique is the best for seizure detection or prediction.Item Mechanisms of Persistently Decreased Inhibition of Area CA1 of the Hippocampus Following Perinatal Hypoxia-induced Seixures(2013-12-17) Justice, Jason ArnoldHypoxia in the neonate is one of the leading causes of encephalopathy and seizures. Sadly, a significant subset of these children will acquire epilepsy, as their risk increases several-fold even with recovery from the initial encephalopathy. Epilepsy can be debilitating and potentially fatal, and can be considered as a condition of hyper-excitable and hyper-synchronistic neural circuitry. Cellular and molecular changes consequent to neonatal seizure-inducing hypoxia are not fully understood, but multiple pro-epileptogenic candidate mechanisms exist. For example, acutely decreased inhibition has been shown at 1 hour post-hypoxia induced seizures, but it is unknown whether this effect is persistent. Such persistent effects on inhibition could promote the development of epilepsy. We designed three specific aims to determine mechanisms of persistently decreased inhibition of area CA1 of the hippocampus following perinatal hypoxia-induced seizures. Specific Aim One was to determine whether the acute (P10) decrease in GABA mediated inhibitory currents, IPSCs, persists beyond the initial 24 hours reported previously. We hypothesized that there would be a persistent increase in inhibition at least one week post hypoxia. Whole-cell voltage-clamp data indicates persistently decreased action potential-dependent GABA-mediated inhibitory post synaptic currents that may possibly be due to decreased interneuron firing. Specific Aim Two was to determine whether there are persistent changes to the composition/expression of the GABAA receptor in hippocampus. We hypothesized that there would be persistent decreases in the overall expression and or composition of the GABAA receptor. Western blot analysis suggests that no change in the expression of ?1, ?2, ?2/3 or ?2 GABA_(A) subunits occurs, at any time point studied, following perinatal hypoxia-induced seizures. Specific Aim Three was to determine whether there are persistent changes in calcineurin expression/activity. We hypothesized that there would be an increase in hippocampal calcineurin expression and/or activity persistently following hypoxia-induced seizures. Western blot data suggests that no change in the expression of calcineurin occurs beyond the initial 24 hours post hypoxia-induced seizures previously reported. Furthermore, calcineurin activity did not increase at 24 hours and 48 hours post hypoxia-induced seizures. Preliminary data suggests activation of an alternative enzymatic pathway, possibly Interleukin-1 receptor dependent activation of casein kinase II, possibly contributing to altered GABAergic inhibition of area CA1 of the hippocampus.Item Medication use patterns of antiepileptics and epileptic events(2012-08) Shcherbakova, Natalia G., 1982-; Rascati, Karen L.; Brown, Carolyn; Lawson, Kenneth; Novak, Suzanne; Richards, Kristin; Yoder, LindaThe purpose of this study was to identify clinical and demographic predictors of seizure recurrence in medically-treated patients with epilepsy. Innovus Invision™ Data Mart insurance claims from January 1, 2007 to September 30, 2010 were retrospectively analyzed. Patients aged 18-64 years with a primary or secondary diagnosis of epilepsy and >1 prescription claim for an antiepileptic drug (AED) pre-index were included. The primary outcome was incidence of seizures defined as an occurrence of an emergency room visit, ambulance service use or hospitalization with a primary or secondary diagnosis of epilepsy during the 1-year follow-up period. Predictor variables included antiepileptic drug (AED) adherence (Proportion of Days Covered ≥ 80 %), general comorbidity (Charlson’s Comorbidity Index ≥ 1), any mental health comorbidity, evidence of a prior seizure, type of epilepsy diagnosis (intractable versus non-intractable), presence of AED-interacting medications and any bioequivalent AED switch. The covariates included age, gender and geographic region of residence. The overall incidence of post-index seizures in the 1-year follow-up period for all four monotherapy cohorts combined was 5.3 % (n=166/3140), but was higher for the Keppra®/levetiracetam cohort (7.9%; n=88/1114) compared to the other cohorts [Lamictal®/lamotrigine (3.9%; n=45/1143), Trileptal®/oxcarbazepine (4.0%; n=18/456) and Topamax®/topiramate (3.5%; n=15/427)]. The combined cohort analysis demonstrated that pre-index seizures (odds ratio [OR] = 4.28; 95% CI, 2.81-6.53), any mental health comorbidity ([OR] = 3.41; 95% CI, 2.10-5.54), Charlson comorbidity Index ≥1 ([OR] = 2.88; 95% CI, 1.96-4.24) and monotherapy with Keppra®/levetiracetam ([OR] = 1.54; 95% CI, 1.03-2.31) were significant predictors of seizure recurrence. Among covariates, only geographic region was a significant predictor, with patients residing in the Northeast U.S. having higher odds of post-index seizure ([OR] = 1.92; 95% CI, 1.19-3.10), while controlling for clinical, medication and demographic characteristics. A bioequivalent AED switch, type of epilepsy diagnosis, AED adherence and the presence of interacting medications were not significant predictors of seizure recurrence in the combined cohort (p>0.05). Results indicate that epilepsy patients with comorbid conditions (both mental and somatic diseases), as well as patients who may have initially been unstable (with previous seizure occurrences) were more likely to experience seizures during the follow-up period.Item The MMPI-2 restructured clinical (RC) scales and measurement of depression in epilepsy(2008-09-19) Simmons, Alexander Douglas; Lacritz, LauraThis study examined the Restructured Clinical (RC) Scales of the Minnesota Multiphasic Personality Inventory-2 (MMPI-2) in a sample of 137 patients with epilepsy. The purposes of the current study were (1) to provide information regarding the psychometric performance of the RC Scales in an epilepsy population, and (2) to examine interpretive characteristics of the RC Scales in an epilepsy population. Internal consistency, internal discriminant validity, and external discriminant and convergent validities were assessed for select RC Scales. Results indicated that the RC Scales showed a modest improvement in general psychometrics over the Clinical Scales. Specifically, the RC Scales displayed slightly better internal consistency and lower scale intercorrelations. Using the Inventory of Depressive Symptomatology, Self Report (IDS-SR) as a criterion, RCd ("demoralization") outperformed RC2 ("low positive emotions") and Scale 2 ("Depression") in predicting depressive severity. Throughout this study, results consistently indicated a close relationship between RC Scales measuring depression, anxiety, and health symptoms; this relationship seemed to reflect comorbidity of symptoms rather than substantial construct overlap. Additionally, several subgroups were defined based on Clinical Scale scores (i.e., a "conversion V" group, a "floating profile" group), and IDS-SR scores; RC Scale scores were examined in these groups. Subjects who demonstrated the conversion V profile tended to have large elevations on RC1 in the absence of comparable elevations on RCd and RC2, and a low score on RC3. Those with a floating profile showed only slight elevations on RCd, RC1 ("health complaints"), RC2, and RC8 ("aberrant experiences"). Subjects classified as at least moderately depressed using the IDS-SR, had only mild elevations on RCd and RD8, with highest elevation for RC1. In summary, the RC Scales showed acceptable performance in this sample, though they were differentially elevated in comparison to the Clinical Scales, indicating that even slight elevations on the RC Scales should be carefully considered in interpretation.Item Neurocognitive and psychosocial functions in children with frontal and temporal lobe epilepsy(2015-08) Stefanatos, Arianna Kyra; Echols, Catharine H.; Nussbaum, Nancy; Holahan, Charles J.; Tucker, David M.; Church-Lang, Jessica A.A key construct at the foundation of cognitive and clinical developmental neuropsychology is the notion that cognitive functions are localized to specific cortical regions in the brain. Consistent with this, relatively stable cognitive and behavioral profiles have been described for adults diagnosed with the two most common focal-onset seizure disorders. Temporal lobe epilepsy (TLE) is primarily associated with impairments in memory functioning (Bell & Giovagnoli, 2007) and frontal lobe epilepsy (FLE) with impairments in executive and motor functioning (Patrikelis et al., 2009). However, the immature brain may be particularly vulnerable to the adverse effects of recurrent seizure activity, showing more widespread effects on cognitive processes and brain organization compared to adults (Korman et al., 2013). Despite these observations, few studies have directly compared performance between children with different epilepsy syndromes utilizing broad assessments spanning multiple domains (Williams, Griebel & Dykman, 1998). Consequently, the aim of this study was to evaluate the degree and selectivity of patterns of cognitive and psychosocial dysfunction in children with TLE and FLE. Participants included 51 children between the ages of 6 and 16 years with intractable epilepsy who were consecutively seen for a neuropsychological evaluation through the Dell Children’s Medical Center Comprehensive Epilepsy Program. During this assessment, participants were administered a battery including measures of memory, executive, motor and intellectual functioning. In addition, parents completed questionnaires regarding their child's behavioral and psychosocial functioning. Contrary to the selective patterns of deficits typically described in adults, both the TLE and FLE groups demonstrated significant impairments relative to normative values on each of the domains assessed. Moreover, no significant differences were found between the two patient groups on any of the measures, with the exception of a task of visual memory. These findings suggest that individuals with childhood-onset epilepsy exhibit fairly broad patterns of cognitive compromise that do not differ significantly with frontal lobe versus temporal lobe seizure localization. Furthermore, the range of deficits observed would not normally be expected with analogous seizure disorders acquired in adulthood. These results provide important insights into the organization of cognitive and behavioral functions following early neurological insults associated with epilepsy.Item A Parent's Guide to Pediatric Epilepsy Surgery(2011-02-01T19:33:00Z) Bagnall, Kristen Marie; Calver, Lewis E.The goal of this project was to create an online parent education resource to guide parents through the process of pediatric epilepsy surgery. I created an interactive, web-based program that included photographs documenting the process, brain scans, illustrations of brain anatomy, success-story videos, frequently asked questions, a glossary, helpful links, and printable PDFs. The program was created for English-speaking families, but it was built with the intention of adding a Spanish version at a later date. The program was also designed as a trusted resource for the families considering epilepsy surgery at Children’s Medical Center, Dallas. The doctors of the Epilepsy Team at Children’s evaluated the program for its clinical relevance and usefulness for their current and future patients. Further testing and feedback from parents can be acquired after the Spanish version is complete and the program is integrated into the website of the Comprehensive Epilepsy Center.Item Parent-Reported Anxiety in Children with Secondary Generalized Seizures(2010-11-02T18:10:23Z) Benitez, Oscar J.; Stavinoha, Peter L.This study examined the role of seizure type in determining different levels of parent-reported anxiety, when taking demographic, medically-related, and medication-related variables into account. One-hundred nineteen children with epilepsy aged 4 to 17 years old underwent a retrospective chart review. Demographic, medically-related, and medication-related variables, such as age, gender, ethnicity, handedness, median household income, age of onset, seizure etiology, lateralization, EEG findings, MRI findings, number of antiepileptic drugs prescribed, side-effect profile of medication, and therapy regimen, were reviewed as well as parent-reported anxiety and depression on the Behavior Assessment System for Children, Second Edition (BASC-2). Findings of the current study replicated previous research suggesting that children with epilepsy have higher average levels of depression and anxiety than the normative population. Children with epilepsy had similar levels of depression, regardless of seizure type. Children with partial seizures with secondary generalization had higher levels of anxiety symptoms compared to children with generalized seizures, but similar levels to those with partial seizures. The current study’s findings could have occurred due to the possible cueing components associated with having partial seizures with secondary generalization. The findings suggest a negative impact that behavioral symptoms of depression and anxiety may have on seizure-related care. The current study expanded upon previous research by using a parent-report measure in which both depression and anxiety scales were normed with the same sample of children. Furthermore, the current study focused on children with secondary generalized seizures as a unique subtype and addressed anxiety specifically, which has been less researched than depression.Item Screening of Mood Disorders Using Self-Reports In Patients with Epilepsy: Sensitivity and Specificity(2007-08-08) Banta Jr., Albert Stephen; Trivedi, MadhukarThe prevalence of mood and anxiety disorders in outpatients with epilepsy seen at a tertiary care epilepsy center and the impact of these disorders on patient quality of life are not well defined. Also methods designed to assist physicians in the rapid diagnosis of these disorders, such as those used by Jones et al 2005a;b, need further assessment. Eligible outpatients (N = 88) with a diagnosis of epilepsy presenting at a tertiary care center were enrolled in the study during October 2006 to May 2007. After providing consent, patients had undergone the 16 item Quick Inventory of Depressive Symptomatology-Self Rating (QIDS-SR16), Beck Depression Inventory-II (BDI-II), Quality of Life Inventory in Epilepsy-31 (QOLE-31) and the Mood Disorders Questionnaire (MDQ). Eligible patients were contacted within three days of initial screening via telephone and underwent the Mini International Neuropsychiatric Interview (MINI) and the 16 item Quick Inventory of Depressive Symptomatology-Clinician Rating (QIDS-C16). A total of 76 patients completed all items and the results indicated a prevalence rate of 32% for current Axis I disorders. The QIDSSR16, QIDS-C16, and BDI-II appeared to be useful in screening for mood and anxiety disorders when compared to psychiatric disorders detected by the MINI. Anxiety disorders were found to be more common than mood disorders and also had a significant negative effect on patients' QOL. The mood disorder group, mood and anxiety disorder group, and mood disorder plus group in this study experienced a greater negative impact on QOL when compared to the Axis I group and the anxiety alone group. Based on this study and Jones et al. (2005a;b) physicians treating patients with epilepsy in tertiary care settings could expect approximately 16-24% of their patients to experience a comorbid mood disorder. Implementation of screening programs that include self-reports are effective at assisting in the clinical identification of patients with mood and/or anxiety disorders so that treatment can be initiated. These psychiatric conditions are associated with a particularly poor quality of life in patients with epilepsy. Increased attention to the presence of psychiatric conditions in patients with epilepsy is important to patient QOL.Item Treatment patterns of antiepileptic drugs and economic outcomes in patients with potential refractory epilepsy in the Texas Medicaid Program(2015-12) Singh, Komal; Wilson, James P.; Barner, Jamie C.; Hovinga, Collin A; Rascati, Karen L; Richards, Kristin MThe purpose of the study was to characterize and compare demographic and clinical characteristics, treatment patterns (i.e., medication adherence, persistence, addition, and switching), and healthcare utilization and cost (i.e., all-cause and epilepsy-related) associated with refractory or non-refractory epilepsy. The study used Texas Medicaid claims data from 09/01/07-12/31/13. Prescription and medical service claims of eligible patients analyzed over a 30-month study period comprised of a 6-month pre-period (baseline) and a 24-month follow-up period (annual increments). Patients eligible for the study: 1) were between 18-62 years of age, 2) had a prescription claim for an antiepileptic drug (AED) during the identification period (03/01/08-12/31/11) with no baseline use of an AED and no prophylactic use of an AED at follow-up, and 3) had evidence of epilepsy diagnosis during the study period. Additionally, patients had to be continuously enrolled in Texas Medicaid with no dual eligibility for Medicare and Medicaid. The index date for both the cohorts was the date of the first AED claim. Dependent variables included: treatment patterns, healthcare utilization and cost. The primary independent variable was group (i.e., refractory vs. non-refractory epilepsy). Based on clinical expert opinion and the literature, patients were categorized as “refractory” (i.e., three or more AEDs, excluding diazepam, in the identification period) and “non-refractory” (i.e., less than three AEDs in the identification period). The covariates included age, gender, race/ethnicity, type of epilepsy, type of index AED, baseline CCI, number of psychiatric comorbidities and presence of non-psychiatric comorbidities at follow-up, baseline pill burden, presence of baseline all-cause inpatient visits, baseline number of all-cause outpatient visits, and baseline all-cause total cost. Using a retrospective matched-cohort design, patients in the refractory cohort were matched 1:1 to patients in the non-refractory cohort using propensity scoring. The matched cohorts were compared for treatment patterns and healthcare utilization and costs using multivariate conditional regression models and non-parametric methods. Of the 10,599 eligible patients, 2,789 (26.3%) patients in the refractory cohort were matched 1:1 to patients in the non-refractory cohort for a total of 5,596 patients. Mean (± SD) age of the patients in the matched cohort was 38.0 (± 13.1) years, and the cohort was comprised of a higher proportion of females (56.0%), Caucasians (41.9%), patients with other convulsions (77.2%), and those with claims for sodium channel blockers (35.4%). A higher proportion of patients with refractory epilepsy were initiated on combination AEDs (26.5% vs. 10.7%), followed by GABA analogues (12.0% vs. 10.2%), and calcium channel action agents (7.7% vs. 3.4%) compared to patients with non-refractory epilepsy. During the second year of follow-up, patients with refractory epilepsy had a higher mean (± SD) (2.1 [± 1.5] vs. 1.8 [± 1.4]) number of psychiatric comorbidities, and a higher proportion (51.3% vs. 41.4%) of patients had one or more non-psychiatric comorbidities compared to patients with non-refractory epilepsy. Regarding treatment patterns, compared to patients with non-refractory epilepsy, patients with refractory epilepsy were 3.6 times (OR=3.553; 95% CI=3.060-4.125; p<0.0001) more likely to adhere to AEDs and had a 34.7% (HR=0.653; 95% CI=0.608-0.702; p<0.0001) lower hazard rate of discontinuation of AEDs during the second-year of follow-up, after controlling for covariates. Among those patients on two or more AEDs, patients with refractory epilepsy were 3.7 times (OR=3.723; 95% CI=2.902-4.776; p<0.0001) more likely to add an alternative AED and 3.6 times (OR=3.591; 95% CI=3.010-4.284; p<0.0001) more likely to switch to an alternative AED during the first-year of follow-up, after controlling for covariates. Regarding healthcare utilization and costs during the second year of follow-up, compared to patients with non-refractory epilepsy, patients with refractory epilepsy had a significantly higher number of all-cause outpatient visits (p<0.0001) and pharmacy claims (p<0.0001), higher epilepsy-related inpatient hospital and emergency department (ED) visits (p<0.0001), outpatient visits (p<0.0001), and pharmacy (p<0.0001) claims, after controlling for covariates. Consequently, these patients incurred higher costs for all-cause outpatient visits (p=0.0190) and pharmacy claims (p<0.0001), and higher costs for epilepsy-related inpatient hospital and ED visits (p<0.0001), outpatient visits (p<0.0001), and pharmacy (p<0.0001) claims, after controlling for covariates. Although a majority of the estimates were higher than the second year of follow-up, a similar trend in results was observed during the first-year of follow-up. In conclusion, findings from this study provide evidence for the dynamic patterns of AED use in clinical practice and provide current estimates of the resource utilization and costs associated with Texas Medicaid patients with refractory epilepsy. Management of epilepsy extends beyond the control of seizures and encompasses improvement in overall burden of the disease. As the costs in the second year were lower than in the first year, timely identification and early treatment optimization may help prevent long-term clinical and economic consequences associated with refractory epilepsy.Item Validation of a Neuropsychological Wada Procedure(2005-08-11) Eisenman, Daniel David; Lacritz, LauraThe Intracarotid amobarbital procedure (IAP) is considered an essential part of the presurgical neurodiagnostic evaluation in most epilepsy centers throughout the country. Despite the IAP's mainstream use, there is great variability in how the test is being performed across centers. The main purpose of this study was to validate a standardized IAP memory measure and explore its value in predicting lateralization as well as treatment outcome. The IAP memory measure had good overall reliability for all three Forms (Cronbach's Alpha = .85 for Form I, .83 for Form II, and .69 for Form III). The majority of items on Form I and II had acceptable item difficulty values, item discrimination values, and item-total correlations. There were a few items on Forms I and II that may be candidates for revision, but most items were only slightly below predicted ranges for what defines a "good" measure, and the majority of items contributed to the reliability of the test. In terms of construct validity, correlations with other memory tests provided some evidence of convergent validity for the IAP memory measure, but were generally low. In terms of divergent validity, both Forms I and II had low or no correlations with the executive functioning measures, providing preliminary support for the construct validity of the measure. When utilizing a discrepancy score to predict lateralization in subjects with temporal lobe epilepsy, asymmetry scores from the IAP memory measure were able to classify 92% of subjects with either left or right TLE after applying a correction factor for left injection scores. There was limited data regarding post-operative seizure outcome. However, seizure-free subjects had a higher percentage of DS greater than 20% than those subjects who reported at least one seizure postoperatively. In addition, there was a significant difference on Form I of the IAP memory measure between subjects who reported they were seizure free following temporal resection as compared to subjects who continued to report symptoms. Overall, the IAP memory measure demonstrated good psychometric properties and this study represents one of the most thorough analyses of the IAP memory test to date.