Temporal lobe epilepsy, depression, and hippocampal volume

Microglia as a Game Changer in Epilepsy Comorbid Depression

As one of the most common neurological diseases, epilepsy is often accompanied by psychiatric disorders. Depression is the most universal comorbidity of epilepsy, especially in temporal lobe epilepsy (TLE). Therefore, it is urgently needed to figure out potential mechanisms and the optimization of therapeutic strategies. Microglia play a pivotal role in the coexistent relationship between epilepsy and depression. Activated microglia released cytokines like IL-6 and IL-1β, orchestrating neuroinflammation especially in the hippocampus, worsening both depression and epilepsy. The decrease of intracellular K+ is a common part in various molecular changes. The P2X7-NLRP3-IL-1β is a major inflammatory pathway that disrupts brain network. Extra ATP and CX3CL1 also lead to neuronal excitotoxicity and blood-brain barrier (BBB) disruption. Regulating neuroinflammation aiming at microglia-related molecules is capable of suspending the vicious mutual aggravating circle of epilepsy and depression. Other overlaps between epilepsy and depression lie in transcriptomic, neuroimaging, diagnosis and treatment. Hippocampal sclerosis (HS) and amygdala enlargement (AE) may be the underlying macroscopic pathological changes according to current studies. Extant evidence shows that cognitive behavioral therapy (CBT) and antidepressants like selective serotonin-reuptake inhibitors (SSRIs) are safe, but the effect is limited. Improvement in depression is likely to reduce the frequency of seizure. More comprehensive experiments are warranted to better understand the relationship between them.

Should artificial intelligence be used in conjunction with Neuroimaging in the diagnosis of Alzheimer's disease?

Alzheimer's disease (AD) is a progressive, neurodegenerative disorder that affects memory, thinking, behavior, and other cognitive functions. Although there is no cure, detecting AD early is important for the development of a therapeutic plan and a care plan that may preserve cognitive function and prevent irreversible damage. Neuroimaging, such as magnetic resonance imaging (MRI), computed tomography (CT), and positron emission tomography (PET), has served as a critical tool in establishing diagnostic indicators of AD during the preclinical stage. However, as neuroimaging technology quickly advances, there is a challenge in analyzing and interpreting vast amounts of brain imaging data. Given these limitations, there is great interest in using artificial Intelligence (AI) to assist in this process. AI introduces limitless possibilities in the future diagnosis of AD, yet there is still resistance from the healthcare community to incorporate AI in the clinical setting. The goal of this review is to answer the question of whether AI should be used in conjunction with neuroimaging in the diagnosis of AD. To answer the question, the possible benefits and disadvantages of AI are discussed. The main advantages of AI are its potential to improve diagnostic accuracy, improve the efficiency in analyzing radiographic data, reduce physician burnout, and advance precision medicine. The disadvantages include generalization and data shortage, lack of in vivo gold standard, skepticism in the medical community, potential for physician bias, and concerns over patient information, privacy, and safety. Although the challenges present fundamental concerns and must be addressed when the time comes, it would be unethical not to use AI if it can improve patient health and outcome.

A PET imaging study of the brain changes of glucose metabolism in patients with temporal lobe epilepsy and depressive disorder

BACKGROUND

This study aims to compare the difference of the brain changes of glucose metabolism between temporal lobe epilepsy patients (TLE) with major depressive disorder and temporal TLE without major depressive disorder.

METHODS

A total of 24 TLE patients, who met the inclusion criteria of our hospital, were enrolled in this study. They were divided into a TLE with depression group (n = 11) and a TLE without depression group (n = 13), according to the results of the HAMD-24 Scale. Two groups patients were examined using 18F-FDG PET brain imaging.

RESULTS

The low metabolic regions of the TLE with depression group were mainly found in the left frontal lobe, temporal lobe and fusiform gyrus, while the high metabolic regions of the TLE with depression group were mainly located in the right frontal lobe, visual joint cortex and superior posterior cingulate cortex. Both of the TLE groups had high metabolic compensation in the non-epileptic area during the interictal period.

CONCLUSIONS

There is an uptake difference of 18F-FDG between TLE patients with depression and TLE patients without depression in multiple encephalic regions.

A systematic review of neuroimaging studies of depression in adults with epilepsy

OBJECTIVE

Depression is a relatively common comorbidity in people with epilepsy with a lifetime history identified in 1 in 4 individuals. In this paper, we aimed to provide a systematic review of structural and functional brain region-specific group differences of adults with epilepsy and depression and to discuss existing evidence as compared to that in people with depression.

METHODS

We undertook a systematic review of neuroimaging studies of depression in adults with epilepsy through MEDLINE/PubMed, Embase and PsycInfo searches until June 2020.

RESULTS

A total of 44 studies were included in the qualitative synthesis: 21 on structural neuroimaging, 9 on functional, and 14 on pharmaco/metabolic neuroimaging. Almost all studies focused on temporal lobe epilepsy (TLE). Patterns of changes in the hippocampi and subcortical structures seem to be different from those reported in depression outside epilepsy. Cortical changes are grossly similar as well as the lack of any laterality effect. Serotonin dysfunction seems to be due to different mechanisms with reduced synaptic availability for depression in epilepsy as compared to reduced 5HT1 receptor density outside epilepsy. Depressive symptoms seem to correlate with a dysfunction in temporolimbic structures contralateral to the epileptogenic zone especially in patients with de novo postsurgical depression.

CONCLUSIONS

Depression, at least in TLE, seems to be associated with a different pattern of brain changes as compared to major depression, potentially supporting the notion of phenomenological peculiarities of depression in epilepsy.

Reduced hippocampal volumes and memory deficits in adolescents with single ventricle heart disease

INTRODUCTION

Adolescents with single ventricle congenital heart disease (SVHD) show functional deficits, particularly in memory and mood regulation. Hippocampi are key brain structures that regulate mood and memory; however, their tissue integrity in SVHD is unclear. Our study aim is to evaluate hippocampal volumes and their associations with memory, anxiety, and mood scores in adolescents with SVHD compared to healthy controls.

METHODS

We collected brain magnetic resonance imaging data from 25 SVHD (age 15.9 ± 1.2 years; 15 male) and 38 controls (16.0 ± 1.1 years; 19 male) and assessed memory (Wide Range Assessment of Memory and Learning 2, WRAML2), anxiety (Beck Anxiety Inventory, BAI), and mood (Patient Health Questionnaire 9, PHQ-9) functions. Both left and right hippocampi were outlined and global volumes, as well as three-dimensional surfaces were compared between groups using ANCOVA and associations with cognitive and behavioral scores with partial correlations (covariates: age and total brain volume).

RESULTS

The SVHD group showed significantly higher BAI (p = .001) and PHQ-9 (p < .001) scores, indicating anxiety and depression symptoms and significantly reduced WRAML2 scores (p < .001), suggesting memory deficits compared with controls. SVHD group had significantly reduced right global hippocampal volumes (p = .036) compared with controls, but not the left (p = .114). Right hippocampal volume reductions were localized in the CA1, CA4, subiculum, and dentate gyrus. Positive correlations emerged between WRAML2 scores and left (r = 0.32, p = .01) and right (r = 0.28, p = .03) hippocampal volumes, but BAI and PHQ-9 did not show significant correlations.

CONCLUSION

Adolescents with SVHD show reduced hippocampal volumes, localized in several sites (CA1, CA4, subiculum, and dentate gyrus), which are associated with memory deficits. The findings indicate the need to explore ways to improve memory to optimize academic achievement and ability for self-care in the condition.

The effects of insular and mesiotemporal lesions on affective information processing: Preliminary evidence from patients with epilepsy surgery

Depressive symptoms and anxiety are common complaints in patients who have had epilepsy surgery. Recent studies have reported disturbances in emotional memory, facial and vocal emotion recognition, and affective learning after temporal lobe and/or insular resection for drug-resistant seizures, suggesting that these regions may be involved in emotional processes underlying psychological symptoms. The insula is a core component of the salience network and is thought to be involved in processing emotions such as disgust, and the role of mesial temporal lobe structures in affective processing is well established. However, to our knowledge, no study has yet investigated whether attentional processing of affective information is altered when these structures are resected as part of an epilepsy surgery. The present study examined the interference control capacity and attentional biases for emotional information in adult patients with epilepsy who underwent temporal lobe resections including the amygdala and hippocampus (n = 15) and/or partial or complete insular resections (n = 16). Patients were tested on an Emotional Stroop test and on a Dot-Probe task using fearful and disgusting pictures and were compared with a healthy control group (n = 30) matched for age, gender, and education. Repeated-measures analyses of variances revealed a significant effect of emotional words on color naming speed in the Emotional Stroop task among insular patients, which was not observed in the other groups. By contrast, the groups did not differ on Dot-Probe task performance. These preliminary findings suggest that insular damage may alter emotional interference control.

Depression and Anxiety in the Epilepsies: from Bench to Bedside

PURPOSE OF REVIEW

Depression and anxiety substantially contribute to interictal disability in patients with epilepsy (PWE). This review summarizes current studies that shed light on mechanisms of comorbidity.

RECENT FINDINGS

Mounting epidemiological data implicate shared risk factors for anxiety/depression and seizure propensity, but these remain largely elusive and probably vary by epilepsy type. Within PWE, these symptoms appear to be associated with unique genetic, neuropathological, and connectivity profiles. Temporal lobe epilepsy has received enormous emphasis particularly in preclinical studies of comorbidity, where candidate neurobiological mechanisms underlying bidirectionality have been tested without psychopharmacological confounds. Depression and anxiety in epilepsy reflect dysfunction within broadly distributed limbic networks that may be the cause or consequence of epileptogenesis. In refractory epilepsy, seizures and/or certain anticonvulsants may distort central emotional homeostatic mechanisms that perpetually raise seizure risk. Developing future safe and effective combined anticonvulsant-antidepressant treatments will require a detailed understanding of anatomical and molecular nodes that pleiotropically enhance seizure risk and negatively alter emotionality.

The effect of left and right long-term amygdala kindling on interictal emotionality and Fos expression

Clinical observations have often reported that patients with seizures arising from limbic structures on the right side of the brain have a higher incidence of emotional disturbances, such as fear and anxiety, than those who have seizures lateralized to limbic structures on the left side. However, there have been some inconsistent reports regarding the presence of these laterality effects. The use of animal models of epilepsy can help circumvent many of the methodological and ethical issues that arise from human clinical studies. In the present study, we examined the unique contribution of left- or right-sided long-term kindling of the amygdala on the development of interictal emotional disturbances. Following kindling to 99 electrical stimulations, male kindled and control rats were examined on a series of behavioral tests - open-field exploration, elevated plus maze, forced swim, and social interaction. Our results revealed that long-term amygdala kindling, irrespective of the hemisphere stimulated, increased general behavioral hyperactivity and fearful behavior. Interestingly, rats that were kindled from the left amygdala showed greater social avoidance and defensive behaviors during interactions with another kindled conspecific. To examine the brain structures that support long-term kindling, we also examined the expression of the immediate early gene product Fos 1 h after rats received their last electrical stimulation. Compared with control rats, kindled rats had increased Fos expression in several brain regions (e.g., piriform, frontal motor cortex, perirhinal cortex) involved in the generation and development of epilepsy. However, decreased Fos expression was also observed in several subregions of the hippocampus and amygdala that are known to be important fear behavior and memory. These findings suggest that both left and right amygdala kindling produce similar changes in emotional behavior and support the idea that the development of kindled fear may result from reduced activation of specific hippocampal and amygdaloid circuits.

Internalizing symptoms in intractable pediatric epilepsy: Structural and functional brain correlates

Internalizing disorders (i.e., depression and anxiety) are common comorbidities in people with epilepsy. In adults with epilepsy, comorbid depression or anxiety is associated with worse seizure control and reduced quality of life, and may be linked to specific neural biomarkers. Less is known about brain correlates of internalizing symptoms in pediatric populations. In the current study, we performed a retrospective analysis of 45 youth between the ages of 6 and 18 years old with intractable epilepsy. Individuals were evaluated for internalizing symptoms on the Child Behavior Checklist (CBCL) and underwent magnetic resonance (MR) and fluorodeoxyglucose (FDG)-positron emission tomography (PET) imaging as part of the clinical evaluation for surgical treatment of epilepsy. Forty-two percent of patients experienced clinically significant internalizing symptoms based on parent report. Compared with individuals who scored in the normal range, youth with clinical levels of internalizing problems showed overall reductions in cortex volume, as well as widespread reductions in cortical thickness and functional activation in the bilateral occipital/parietal lobe, left temporal regions, and left inferior frontal cortex on MR and PET scans. There were no group differences in amygdala or hippocampus volumes, nor other patient- or illness-related variables such as age, sex, or the type, lateralization, or duration of epilepsy. Results suggest that high rates of internalizing disorders are present in youth with refractory epilepsy. Multifocal reductions in cortical thickness and function may be nonspecific risk factors for clinically meaningful internalizing symptoms in youth with chronic epilepsy. As such, the presence of broad cortical thinning and reduced glucose uptake upon radiological examination may warrant more focused clinical evaluation of psychological symptoms.

Major Depressive Disorder Associated With Reduced Cortical Thickness in Women With Temporal Lobe Epilepsy

Background: Major Depressive Disorder (MDD) is highly prevalent in patients with mesial temporal lobe epilepsy (MTLE), especially in women, carrying significant morbidity. This study aimed to investigate the cortical thickness (CT) abnormalities associated with MDD in women with MTLE and hippocampal atrophy (HA). Also, we investigated the impact of MDD upon the volumes of the hippocampus and amygdala in these patients.

Methods: We included 50 women with MTLE and HA (20 left, LMTLE; 30 right, RMTLE), 41 healthy women in the control group, and 15 women with MDD without epilepsy. MTLE patients were subdivided into three groups: MTLE-without-MDD (23 MTLE patients without MDD), MTLE-mild-MDD (nine MTLE patients with mild symptoms of MDD), and MTLE-severe-MDD (18 MTLE patients with moderate to severe symptoms of MDD). The five groups were balanced for age (p = 0.56). All participants had high-resolution 3D T1-weighted images in a 3T scanner. We used FreeSurfer 6.0 for volumetry and CT parcellation. All participants were submitted to a clinical psychological evaluation through the Structured Clinical Interview for DSM-IV (SCID-IV) and completed the Beck Depression Inventory (BDI-II).

Results: We identified a smaller ipsilateral amygdala volume (p = 0.04) in the MTLE-severe-MDD group when compared to the control group. Our results presented a reduced ipsilateral lateral orbitofrontal cortex (p = 0.02) in the MTLE-severe-MDD in comparison to the MTLE-mild-MDD group. We also identified a thinner ipsilateral fusiform gyrus (p < 0.01) in the MTLE-severe-MDD compared to both MTLE-without-MDD and control groups. A reduced CT of the contralateral superior frontal gyrus (p = 0.02) was observed in the MTLE-severe-MDD in comparison to the MTLE-mild-MDD group.

Conclusions: The identification of areas with reduced CT and atrophy of the ipsilateral amygdala in women with MTLE and MDD suggest that the cortical thinning in the network of the paralimbic system is related to the co-occurrence and intensity of depressive symptoms in this group.

Mechanisms of Psychiatric Comorbidities in Epilepsy

Psychiatric illnesses, including depression and anxiety, are highly comorbid with epilepsy (for review see Josephson and Jetté (Int Rev Psychiatry 29:409-424, 2017), Salpekar and Mula (Epilepsy Behav 98:293-297, 2019)). Psychiatric comorbidities negatively impact the quality of life of patients (Johnson et al., Epilepsia 45:544-550, 2004; Cramer et al., Epilepsy Behav 4:515-521, 2003) and present a significant challenge to treating patients with epilepsy (Hitiris et al., Epilepsy Res 75:192-196, 2007; Petrovski et al., Neurology 75:1015-1021, 2010; Fazel et al., Lancet 382:1646-1654, 2013) (for review see Kanner (Seizure 49:79-82, 2017)). It has long been acknowledged that there is an association between psychiatric illnesses and epilepsy. Hippocrates, in the fourth-fifth century B.C., considered epilepsy and melancholia to be closely related in which he writes that "melancholics ordinarily become epileptics, and epileptics, melancholics" (Lewis, J Ment Sci 80:1-42, 1934). The Babylonians also recognized the frequency of psychosis in patients with epilepsy (Reynolds and Kinnier Wilson, Epilepsia 49:1488-1490, 2008). Despite the fact that the relationship between psychiatric comorbidities and epilepsy has been recognized for thousands of years, psychiatric illnesses in people with epilepsy still commonly go undiagnosed and untreated (Hermann et al., Epilepsia 41(Suppl 2):S31-S41, 2000) and systematic research in this area is still lacking (Devinsky, Epilepsy Behav 4(Suppl 4):S2-S10, 2003). Thus, although it is clear that these are not new issues, there is a need for improvements in the screening and management of patients with psychiatric comorbidities in epilepsy (Lopez et al., Epilepsy Behav 98:302-305, 2019) and progress is needed to understand the underlying neurobiology contributing to these comorbid conditions. To that end, this chapter will raise awareness regarding the scope of the problem as it relates to comorbid psychiatric illnesses and epilepsy and review our current understanding of the potential mechanisms contributing to these comorbidities, focusing on both basic science and clinical research findings.

Preclinical evidence of ghrelin as a therapeutic target in epilepsy

Ghrelin, an orexigenic peptide synthesized by endocrine cells of the gastric mucosa, plays a major role in inhibiting seizures. However, the underlying mechanism of ghrelin's anticonvulsant action is still unclear. Nowadays, there are considerable evidences showing that ghrelin is implicated in various neurophysiological processes, including learning and memory, neuroprotection, neurogenesis, and inflammatory effects. In this review, we will summarize the effects of ghrelin on epilepsy. It may provide a comprehensive picture of the role of ghrelin in epilepsy.

To what extent does depression influence quality of life of people with pharmacoresistant epilepsy in Argentina?

INTRODUCTION

Depression is the most frequent psychiatric co-morbidity in patients with epilepsy. Lifetime prevalence of depression is reported more frequently in temporal lobe epilepsy and is estimated at 35%. This co-morbidity appears to be related with various mechanisms. The aim of this study was to determine the quality of life (QoL) of patients with pharmacoresistant epilepsy with and without co-morbid depression in an Argentinean population.

METHODS

Patients admitted to the video-EEG monitoring unit during the period 2010-2013 went through a standardized psychiatric assessment using SCID-I (Structured Clinical Interview for Axis I diagnoses of DSM-IV), BDI II (Beck Depression Inventory) GAF (Global assessment of functioning), and Q LES Q-SF (for quality of life). Patients were divided in two groups: with and without depression (according to DSM-IV). Sociodemographic data, BDI II scores, GAF, and quality of life (QoL) were compared between the two groups. Comparisons were made using Student's t-test and Mann-Whitney U test. Frequency distributions were compared by Chi-square test. Spearman correlation coefficients were determined.

RESULTS

Seventy-seven patients with pharmacoresistant epilepsy were eligible for this study, 41 patients were included in the group with depression (mean BDI II 15.93), and 36 in the group without depression (mean BDI II 3.36) (p=0.001). The overall QoL was significantly lower in the group with depression compared to the group without depression (p<0.01). The most affected areas were: physical health (p=0.013), mood (p=0.006), course activities (referring to school as well as to hobbies or classes outside of school) (p=0.003), leisure time activities (p=0.011), social activities (p=0.047), general activities (p=0.042), and medication (p=0.022). Severity of depression according to BDI II had a negative correlation with overall QoL (r - 0.339, p<0.01). No correlations were found between seizure frequency, QoL and BDI II.

CONCLUSION

Patients with pharmacoresistant epilepsy and co-morbid depression reported worst QoL. Depression disrupts daily functioning (leisure, social functioning) and is a negative influence for subjective perception of health and medication. Interdisciplinary treatment should be considered (neurology-psychiatry-psychotherapy).

Mood Disorders in Epilepsy

Mood disorders associated with epilepsy are very common and overrepresented compared with other chronic medical conditions. Depression is a particularly common and worrisome comorbidity, especially because suicidality seems to be increased significantly in the context of epilepsy. Although psychosocial stressors commonly are associated, intrinsic characteristics of seizure disorders may contribute to the expression of depressive symptoms. Depression and epilepsy may exacerbate each other. Epilepsy with seizure foci in the temporal lobe may represent a higher risk of developing depression, especially if the seizures do not generalize. Treatment of depression is multifaceted and includes psychotherapy and sophisticated regimens of anticonvulsants. Most antidepressants may be used safely and effectively in the context of depression, although high-quality evidence is lacking. Ultimately, treatment of comorbid mood disorder has important implications for outcome and quality of life, perhaps even more than treatment of epilepsy itself.

Depression and anxiety in children with benign childhood epilepsy with centrotemporal spikes (BCECTS)

Background

Elevated rates of affective disturbance in children with benign childhood epilepsy with centrotemporal spikes (BCECTS) have been reported. However, it remains unclear how anxiety and depression are related to epilepsy, and it is unknown whether these mood disorders are influenced by the use of antiepileptic drugs. In the present report, we performed a prospective study designed to evaluate affective disorders (anxiety and depression) without the bias of antiepileptic drug treatment in 89 children with BCECTS, based on self-reporting. Furthermore, we sought to determine whether clinical factors, such as age, disease course, seizure frequency, and spike wave index (SWI), were related to the psychological profiles.

Methods

Patients with BCECTS (n = 89) and healthy matched controls (n = 75) were included in this study. The Depression Self-Rating Scale for Children (DSRSC) and the Screen for Child Anxiety-Related Emotional Disorders (SCARED) were completed by the children.

Results

None of the children met criteria for clinically significant anxiety or depression. However, the children with BCECTS had significantly higher depression and anxiety scores compared with children in the control group. We found no significant differences in depression or anxiety between the left, right, and bilateral lobe groups. The DSRSC scores were similar between the children with partial seizures and those with secondarily generalized seizures. Similarly, there were no significant differences in the SCARED scores between these two groups. However, the DSRSC and SCARED scores were positively correlated with age, seizure frequency, SWI, and disease course.

Conclusions

The children with BCECTS had an increased likelihood of depression and anxiety, and these higher rates were unrelated to seizure type or epileptic focus, but were positively correlated with age, seizure frequency, SWI, and disease course.

Common Mechanisms Underlying Epileptogenesis and the Comorbidities of Epilepsy

The importance of comorbidities in determining the quality of life of individuals with epilepsy and their families has received increasing attention in the past decade. Along with it has come a recognition that in some individuals, certain comorbidities may have preexisted, and may have contributed to their developing epilepsy. Many mechanisms are capable of interconnecting different dysfunctions that manifest as distinct disorders, often diagnosed and managed by different specialists. We review the human data from the perspective of epidemiology as well as insights gathered from neurodiagnostic and endocrine studies. Animal studies are reviewed to refine our mechanistic understanding of the connections, because they permit the narrowing of variables, which is not possible when studying humans.

Right fronto-limbic atrophy is associated with reduced empathy in refractory unilateral mesial temporal lobe epilepsy

Refractory mesial temporal lobe epilepsy (MTLE) is the most frequent focal epilepsy and is often accompanied by deficits in social cognition including emotion recognition, theory of mind, and empathy. Consistent with the neuronal networks that are crucial for normal social-cognitive processing, these impairments have been associated with functional changes in fronto-temporal regions. However, although atrophy in unilateral MTLE also affects regions of the temporal and frontal lobes that underlie social cognition, little is known about the structural correlates of social-cognitive deficits in refractory MTLE. In the present study, a psychometrically validated empathy questionnaire was combined with whole-brain voxel-based morphometry (VBM) to investigate the relationship between self-reported affective and cognitive empathy and gray matter volume in 55 subjects (13 patients with right MTLE, 9 patients with left MTLE, and 33 healthy controls). Consistent with the brain regions underlying social cognition, our results show that lower affective and cognitive empathy was associated with smaller volume in predominantly right fronto-limbic regions, including the right hippocampus, parahippocampal gyrus, thalamus, fusiform gyrus, inferior temporal gyrus, dorsomedial and dorsolateral prefrontal cortices, and in the bilateral midbrain. The only region that was associated with both affective and cognitive empathy was the right mesial temporal lobe. These findings indicate that patients with right MTLE are at increased risk for reduced empathy towards others' internal states and they shed new light on the structural correlates of impaired social cognition frequently accompanying refractory MTLE. In line with previous evidence from patients with neurodegenerative disease and stroke, the present study suggests that empathy depends upon the integrity of right fronto-limbic and brainstem regions and highlights the importance of the right mesial temporal lobe and midbrain structures for human empathy.

MRI characterization of temporal lobe epilepsy using rapidly measurable spatial indices with hemisphere asymmetries and gender features

INTRODUCTION

The paucity of morphometric markers for hemispheric asymmetries and gender variations in hippocampi and amygdalae in temporal lobe epilepsy (TLE) calls for better characterization of TLE by finding more useful prognostic MRI parameter(s).

METHODS

T1-weighted MRI (3 T) morphometry using multiple parameters of hippocampus-parahippocampus (angular and linear measures, volumetry) and amygdalae (volumetry) including their hemispheric asymmetry indices (AI) were evaluated in both genders. The cutoff values of parameters were statistically estimated from measurements of healthy subjects to characterize TLE (57 patients, 55% male) alterations.

RESULTS

TLE had differential categories with hippocampal atrophy, parahippocampal angle (PHA) acuteness, and several other parametric changes. Bilateral TLE categories were much more prevalent compared to unilateral TLE categories. Female patients were considerably more disposed to bilateral TLE categories than male patients. Male patients displayed diverse categories of unilateral abnormalities. Few patients (both genders) had combined bilateral appearances of hippocampal atrophy, amygdala atrophy, PHA acuteness, and increase in hippocampal angle (HA) where medial distance ratio (MDR) varied among genders. TLE had gender-specific and hemispheric dominant alterations in AI of parameters. Maximum magnitude of parametric changes in TLE includes (a) AI increase in HA of both genders, (b) HA increase (bilateral) in female patients, and (c) increase in ratio of amygdale/hippocampal volume (unilateral, right hemispheric), and AI decrease in MDR, in male patients.

CONCLUSION

Multiparametric MRI studies of hippocampus and amygdalae, including their hemispheric asymmetry, underscore better characterization of TLE. Rapidly measurable single-slice parameters (HA, PHA, MDR) can readily delineate TLE in a time-constrained clinical setting, which contrasts with customary three-dimensional hippocampal volumetry that requires many slice computation.

Depression screening in pediatric epilepsy: evidence for the benefit of a behavioral medicine service in early detection

Despite the increased risk and prevalence of depression in youth with epilepsy, only one-third receive mental health services. Untreated depression can contribute to negative outcomes and increased health-care utilization and medical cost. Proactive behavioral medicine screening may facilitate identification of depressive symptoms and necessary interventions in efforts to optimize behavioral health and health-related quality of life (HRQOL). Primary study aims included the examination of 1) rates of self-reported depression in youth with epilepsy, 2) differences in depression by demographic and medical variables, 3) the impact of depression on HRQOL, and 4) changes in depression and suicidal ideation following a behavioral medicine consultation. As part of routine clinic care over a 24-month period, youth with epilepsy of 7-17years of age completed the Children's Depression Inventory-Second Edition. Parents completed the PedsQL. A chart review was conducted to ascertain demographics, medical variables, and behavioral medicine visits and recommendations. A subsample with Time 1 and Time 2 depression data was examined. Time 1 participants included 311 youth with epilepsy (Mage=11.9years, 50% female, 84% Caucasian, 46.0% with localization-related epilepsy, 71.0% with seizure control in the past 3months). Elevated depression was identified in 23% of youth, with 14% endorsing suicidal ideation. Depression significantly varied by age, antiepileptic drug, and insurance. After controlling for seizure status, HRQOL worsened with elevated depression. Depression significantly decreased from Time 1 to Time 2 (n=159), particularly for those referred for behavioral medicine services at Time 1. Systematic assessment and early detection of depression and/or suicidal ideation in youth with epilepsy can improve HRQOL and decrease depression. Depression screening can be implemented through clinic-based behavioral medicine services.

Temporal lobe epilepsy and affective disorders: the role of the subgenual anterior cingulate cortex

OBJECTIVE

Reduced deactivation within the default mode network (DMN) is common in individuals with primary affective disorders relative to healthy volunteers (HVs). It is unknown whether similar network abnormalities are present in temporal lobe epilepsy (TLE) patients with a history of affective psychopathology.

METHODS

17 TLE patients with a lifetime affective diagnosis, 31 TLE patients with no formal psychiatric history and 30 HVs were included. We used a visuo-spatial 'n-back' paradigm to compare working memory (WM) network activation between these groups. Post hoc analyses included voxel-based morphometry and diffusion tensor imaging. The Beck Depression Inventory-Fast Screen and Beck Anxiety Inventory were completed on the day of scanning.

FINDINGS

Each group activated the fronto-parietal WM networks and deactivated the typical DMN in response to increasing task demands. Group comparison revealed that TLE patients with lifetime affective morbidity showed significantly greater deactivation in subgenual anterior cingulate cortex (sACC) than either the TLE-only or the HVs (p<0.001). This effect persisted after covarying for current psychotropic medication and severity of current depressive/anxiety symptoms (all p<0.001). Correlational analysis revealed that this finding was not driven by differences in task performance. There were no significant differences in grey matter volume or structural connectivity between the TLE groups.

CONCLUSIONS

Our results provide novel evidence suggesting that affective psychopathology in TLE has a neurobiological correlate, and in this context the sACC performs differently compared with network activity in primary affective disorders.

Severe hippocampal atrophy is not associated with depression in temporal lobe epilepsy

Depression in temporal lobe epilepsy (TLE) is common, is a strong predictor of subjective disability, and may have unique pathophysiological characteristics. Previous studies showed that reduced hippocampal volume is associated with significant depressive symptoms in patients with TLE. We utilized regions of interest analysis of high-resolution brain MRI and a reliable and valid measure of depressive symptoms to evaluate 28 consecutive adult subjects with video-EEG-confirmed TLE. Regions of interest were based on prior human and animal studies of mood and behavioral dysfunction. Forty-three percent of the entire group had significant symptoms of depression, defined by a Beck Depression Inventory (BDI) score of greater than 15. Total hippocampal volumes were significantly smaller in the group with BDI<15, (p<0.007). None of the subjects in the quartile with the smallest left hippocampal volume had a BDI score greater than 15 compared with 57% of the subjects in the upper three quartiles (p<0.008). No other limbic brain structures (amygdala, subcallosal gyrus, subgenual gyrus, gyrus rectus), or total cerebral volume were associated with depressive symptoms. Adequate hippocampal integrity may be necessary to maintain depression symptoms in mesial temporal lobe epilepsy. This finding also supports the possibility of a unique mechanism for depression in mesial temporal lobe epilepsy, such as hyperexcitable neuronal influence on the limbic network.

Clinical risk factors for depressive symptoms in patients with epilepsy

BACKGROUND AND AIMS

To investigate the relationships between demographic data, seizure-related factors, anti-epileptic drugs (AEDs) taking, and depressive symptoms in patients with epilepsy (PWE), determining the major clinical risk factors of depression.

METHODS

Patients with epilepsy who visited our epilepsy clinic from 2010 to 2012 were included. The clinical data were collected, and Hamilton Depression Rating Scale (HAMD), National Hospital Seizure Severity Scale (NHS3) and Pittsburgh Sleep Quality Index (PSQI) were evaluated.

RESULTS

A total of 116 PWE were recruited. They were divided into three groups. Age, duration of epilepsy, percentages of patients with partial seizures, history of status epilepticus (SE), using topiramate (TPM) or clonazepam (CZP), and using greater than or equal to 2 types of AEDs were all significantly higher in patients with moderate depressive symptoms than patients without depression. HAMD scores were positively correlated with age, duration of epilepsy, and the number of AEDs taking, respectively. PSQI scores were positively correlated with HAMD scores in patients with depressive symptoms. Age greater than 35 years, females, having partial seizures, history of SE, and using TPM were independent predictors of depressive symptoms in PWE by regression analysis.

CONCLUSIONS

Age greater than 35 years, females, having partial seizures, history of SE, and using TPM might become risk factors for depressive symptoms in PWE.

Biomarkers of epileptogenesis: psychiatric comorbidities (?)

The last decade has witnessed a significant shift on our understanding of the relationship between psychiatric disorders and epilepsy. While traditionally psychiatric disorders were considered as a complication of the underlying seizure disorder, new epidemiologic data, supported by clinical and experimental research, have suggested the existence of a bidirectional relation between the two types of conditions: not only are patients with epilepsy at greater risk of experiencing a psychiatric disorder, but patients with primary psychiatric disorders are at greater risk of developing epilepsy. Do these data suggest that some of the pathogenic mechanisms operant in psychiatric comorbidities play a role in epileptogenesis? The aim of this article is to review the epidemiologic data that demonstrate that primary psychiatric disorders are more frequent in people who develop epilepsy, before the onset of the seizure disorder than among controls. The next question looks at the available data of pathogenic mechanisms of primary mood disorders and their potential for facilitating the development and/or exacerbation in the severity of epileptic seizures. Finally, we review data derived from experimental studies in animal models of depression and epilepsy that support a potential role of pathogenic mechanisms of mood disorders in the development of epileptic seizures and epileptogenesis. The data presented in this article do not yet establish conclusive evidence of a pathogenic role of psychiatric comorbidities in epileptogenesis, but raise important research questions that need to be investigated in experimental, clinical, and population-based epidemiologic research studies.

Hippocampal volumes in juvenile neuronal ceroid lipofuscinosis: a longitudinal magnetic resonance imaging study

BACKGROUND

Juvenile neuronal ceroid lipofuscinosis is an inherited, autosomal recessive, progressive, neurodegenerative disorder of childhood. It belongs to the lysosomal storage diseases, which manifest with loss of vision, seizures, and loss of cognitive and motor functions, and lead to premature death. Imaging studies have shown cerebral and cerebellar atrophy, yet no previous studies evaluating particularly hippocampal atrophy have been published. This study evaluates the hippocampal volumes in adolescent juvenile neuronal ceroid lipofuscinosis patients in a controlled 5-year follow-up magnetic resonance imaging study.

METHODS

Hippocampal volumes of eight patients (three female, five male) and 10 healthy age- and sex-matched control subjects were measured from two repeated magnetic resonance imaging examinations. Three male patients did not have controls and were excluded from the statistics. In the patient group, the first examination was performed at the mean age of 12.2 years and the second examination at the mean age of 17.3 years. In the control group, the mean ages at the time of examinations were 12.5 years and 19.3 years.

RESULTS

Progressive hippocampal atrophy was found in the patient group. The mean total hippocampal volume decreased by 0.85 cm³ during the 5-year follow-up in the patient group, which corresponds to a 3.3% annual rate of volume loss. The whole brain volume decreased by 2.9% per year. The observed annual rate of hippocampal atrophy also exceeded the previously reported 2.4% annual loss of total gray matter volume in juvenile neuronal ceroid lipofuscinosis patients.

CONCLUSIONS

These data suggest that progressive hippocampal atrophy is one of the characteristic features of brain atrophy in juvenile neuronal ceroid lipofuscinosis in adolescence.

Hippocampal volume and memory performance in children with perinatal stroke

BACKGROUND

Pediatric neurologists and neonatologists often are asked to predict cognitive outcome after perinatal brain injury (including likely memory and learning outcomes). However, relatively few data exist on how accurate predictions can be made. Furthermore, although the consequences of brain injury on hippocampal volume and memory performance have been studied extensively in adults, little work has been done in children.

METHODS

We measured the volume of the hippocampus in 27 children with perinatal stroke and 19 controls, and measured their performance on standardized verbal and non-verbal memory tests.

RESULTS

We discovered the following: (1) As a group, children with perinatal stroke had smaller left and right hippocampi compared with control children. (2) Individually, children with perinatal stroke demonstrated 1 of 3 findings: no hippocampal loss, unilateral hippocampal loss, or bilateral hippocampal volume loss compared with control children. (3) Hippocampal volume inversely correlated with memory test performance in the perinatal stroke group, with smaller left and right hippocampal volumes related to poorer verbal and non-verbal memory test performance, respectively. (4) Seizures played a significant role in determining memory deficit and extent of hippocampal volume reduction in patients with perinatal stroke.

CONCLUSIONS

These findings support the view that, in the developing brain, the left and right hippocampi preferentially support verbal and nonverbal memory respectively, a consistent finding in the adult literature but a subject of debate in the pediatric literature. This is the first work to report that children with focal brain injury incurred from perinatal stroke have volume reduction in the hippocampus and impairments in certain aspects of declarative memory.

Neural correlates of de novo depression following left temporal lobe epilepsy surgery: a voxel based morphometry study of pre-surgical structural MRI

PURPOSE

To investigate cerebral grey matter (GM) volumetric abnormalities in temporal lobe epilepsy (TLE) patients who develop de novo depression following TLE surgery using voxel-based morphometry (VBM).

METHODS

We retrospectively examined pre-surgical grey matter (GM) volumes in 30 patients with TLE due to unilateral left-sided hippocampal sclerosis using 1.5-T MRI scan, which were segmented with optimised VBM parameters and normalised to a sample template using DARTEL, with SPM8 software. Voxel-wise GM differences between patients that developed de novo post-surgical depression (n=5) were compared with patients with no pre- or postoperative psychiatric diagnoses (n=25), using independent samples t-tests with age, gender and secondary generalised tonic-clonic seizures (SGTCS) as covariates (p<.001, unc).

KEY FINDINGS

Reduced preoperative bilateral GM in orbitofrontal cortices (OFC) and ipsilateral cingulate gyrus and thalamus were significantly associated with the development of de novo depression within 4 years postoperatively. Further analyses revealed no differences in seizure freedom (ILAE 1 vs 2-6) or postoperative memory decline between the groups.

SIGNIFICANCE

Although the development of postoperative de novo depression following TLE surgery is likely to be multi-factorial, our results suggest that bilateral OFC and ipsilateral cingulate gyrus and thalamic atrophy in left-sided TLE patients may play a modulatory role. Abnormalities in these areas have also been implicated in primary mood disorders. Prospective neuroimaging studies with larger cohorts are warranted to replicate these results, and further elucidate the neural correlates of de novo depression.

Alterations in functional connectivity between the hippocampus and prefrontal cortex as a correlate of depressive symptoms in temporal lobe epilepsy

Depression is a common comorbidity in temporal lobe epilepsy (TLE) that is thought to have a neurobiological basis. This study investigated the functional connectivity (FC) of medial temporal networks in depression symptomatology of TLE and the relative contribution of structural versus FC measures. Volumetric MRI and functional connectivity MRI (fcMRI) were performed on nineteen patients with TLE and 20 controls. The hippocampi and amygdalae were selected as seeds, and five prefrontal and five cingulate regions of interest (ROIs) were selected as targets. Low-frequency blood-oxygen-level-dependent signals were isolated from fcMRI data, and ROIs with synchronous signal fluctuations with the seeds were identified. Depressive symptoms were measured by the Beck Depression Inventory-II. The patients with TLE showed greater ipsilateral hippocampal atrophy (HA) and reduced FC between the ipsilateral hippocampus and the ventral posterior cingulate cortex (vPCC). Neither HA nor hippocampal-vPCC FC asymmetry was a robust contributor to depressive symptoms. Rather, hippocampal-anterior prefrontal FC was a stronger contributor to depressive symptoms in left TLE (LTLE). Conversely, right amygdala FC was correlated with depressive symptoms in both patient groups, with a positive and negative correlation in LTLE and right TLE (RTLE), respectively. Frontolimbic network dysfunction is a strong contributor to levels of depressive symptoms in TLE and a better contributor than HA in LTLE. In addition, the right amygdala may play a role in depression symptomatology regardless of the side of the epileptogenic focus. These findings may inform the treatment of depressive symptoms in TLE and inspire future research to help guide surgical planning.

Resting state networks in temporal lobe epilepsy

Temporal lobe epilepsy (TLE) is typically described as a neurologic disorder affecting a cerebral network comprising the hippocampus proper and several anatomically related extrahippocampal regions. A new level of complexity was recently added to the study of this disorder by the evidence that TLE also appears to chronically alter the activity of several brain-wide neural networks involved in the control of higher order brain functions and not traditionally linked to epilepsy. Recently developed brain imaging techniques such as functional magnetic resonance imaging (fMRI) analysis of resting state connectivity, have greatly contributed to these observations by allowing the precise characterization of several brain networks with distinct functional signatures in the resting brain, and therefore also known as "resting state networks." These significant advances in imaging represent an opportunity to investigate the still elusive origins of the disabling cognitive and psychiatric manifestations of TLE, and could have important implications for its pathophysiology and, perhaps, its therapy. Herein we review recent studies in this field by focusing on resting state networks that have been implicated in the pathophysiology of psychiatric disorders and cognitive impairment in patients with epilepsy: the default mode network, the attention network, and the reward/emotion network.

Increased ratio of glutamate/glutamine to creatine in the right hippocampus contributes to depressive symptoms in patients with epilepsy

PURPOSE

Our study aimed to investigate whether the glutamatergic system in the hippocampus is correlated with depressive symptoms in patients with epilepsy.

METHODS

Fifty patients with epilepsy were recruited and divided into three groups on the basis of their Hamilton Depression Rating Scale (HAMD) scores. Single-voxel proton magnetic resonance spectroscopy ((1)H-MRS) was carried out. Pearson correlation analysis and multiple linear regression analysis were performed to investigate any correlation between the variables of hippocampal metabolites and HAMD scores.

RESULTS

Proton magnetic resonance spectroscopy analysis showed that the ratio of glutamate/glutamine to creatine (Glx/Cr) in the right hippocampus was significantly increased in patients with moderate depression and correlated positively with HAMD scores. Multiple linear regression analysis showed that the ratio of Glx/Cr in the right hippocampus was an independent risk factor relating to depressive symptoms in patients with epilepsy.

CONCLUSION

A disturbance of the hippocampal glutamatergic system may be involved in the pathogenesis of depression in epilepsy.

Psychiatric symptoms in children prior to epilepsy surgery differ according to suspected seizure focus

PURPOSE

Children and adolescents with epilepsy have an overrepresentation of psychiatric illness. However, few studies in pediatrics have characterized specific psychiatric conditions associated with seizure localization. In addition, degree to which psychiatric illness may be more prominent in children refractory to standard medical treatment for epilepsy is not known. The aim of this study was to assess psychiatric symptoms in children with medically refractory epilepsy and ascertain whether symptoms were associated with specific localization.

METHODS

Case records were reviewed for 40 children with medically refractory epilepsy at the time of their referral for presurgical evaluation. Patients received a clinical psychiatric evaluation and parents completed the Child Behavioral Checklist (CBCL). Seizure localization was verified by pediatric epileptologists, and suitability for surgical procedures was verified by neurosurgical specialists. Groups were compared based on localization of seizure foci, either in the temporal lobe or predominantly extratemporal.

KEY FINDINGS

The majority of the sample had psychiatric diagnoses and behavior problems, well beyond the level reported in chronic epilepsy populations. In addition, children with temporal lobe seizure foci had more CBCL behavioral problem categories rated in the clinically significant range, and also were more likely to have clinical diagnoses of depression.

SIGNIFICANCE

Routine psychiatric evaluation prior to epilepsy surgery may be important for pediatric patients with medically refractory epilepsy. Psychiatric illness, particularly depression, may be especially prominent for those with temporal lobe seizure foci.

Stress, seizures, and hypothalamic-pituitary-adrenal axis targets for the treatment of epilepsy

Epilepsy is a heterogeneous condition with varying etiologies including genetics, infection, trauma, vascular, neoplasms, and toxic exposures. The overlap of psychiatric comorbidity adds to the challenge of optimal treatment for people with epilepsy. Seizure episodes themselves may have varying triggers; however, for decades, stress has been commonly and consistently suspected to be a trigger for seizure events. This paper explores the relationship between stress and seizures and reviews clinical data as well as animal studies that increasingly corroborate the impact of stress hormones on neuronal excitability and seizure susceptibility. The basis for enthusiasm for targeting glucocorticoid receptors for the treatment of epilepsy and the mixed results of such treatment efforts are reviewed. In addition, this paper will highlight recent findings identifying a regulatory pathway controlling the body's physiological response to stress which represents a novel therapeutic target for modulation of the hypothalamic-pituitary-adrenal (HPA) axis. Thus, the HPA axis may have important clinical implications for seizure control and imply use of anticonvulsants that influence this neuronal pathway.

Effect of diet on serotonergic neurotransmission in depression

Depression is characterized by sadness, purposelessness, irritability, and impaired body functions. Depression causes severe symptoms for several weeks, and dysthymia, which may cause chronic, low-grade symptoms. Treatment of depression involves psychotherapy, medications, or phototherapy. Clinical and experimental evidence indicates that an appropriate diet can reduce symptoms of depression. The neurotransmitter, serotonin (5-HT), synthesized in the brain, plays an important role in mood alleviation, satiety, and sleep regulation. Although certain fruits and vegetables are rich in 5-HT, it is not easily accessible to the CNS due to blood brain barrier. However the serotonin precursor, tryptophan, can readily pass through the blood brain barrier. Tryptophan is converted to 5-HT by tryptophan hydroxylase and 5-HTP decarboxylase, respectively, in the presence of pyridoxal phosphate, derived from vitamin B(6). Hence diets poor in tryptophan may induce depression as this essential amino acid is not naturally abundant even in protein-rich foods. Tryptophan-rich diet is important in patients susceptible to depression such as certain females during pre and postmenstrual phase, post-traumatic stress disorder, chronic pain, cancer, epilepsy, Parkinson's disease, Alzheimer's disease, schizophrenia, and drug addiction. Carbohydrate-rich diet triggers insulin response to enhance the bioavailability of tryptophan in the CNS which is responsible for increased craving of carbohydrate diets. Although serotonin reuptake inhibitors (SSRIs) are prescribed to obese patients with depressive symptoms, these agents are incapable of precisely regulating the CNS serotonin and may cause life-threatening adverse effects in the presence of monoamine oxidase inhibitors. However, CNS serotonin synthesis can be controlled by proper intake of tryptophan-rich diet. This report highlights the clinical significance of tryptophan-rich diet and vitamin B(6) to boost serotonergic neurotransmission in depression observed in various neurodegenerative diseases. However pharmacological interventions to modulate serotonergic neurotransmission in depression, remains clinically significant. Depression may involve several other molecular mechanisms as discussed briefly in this report.

Depression and epilepsy: epidemiologic and neurobiologic perspectives that may explain their high comorbid occurrence

Depression is the most frequent psychiatric comorbidity in people with epilepsy (PWE) with lifetime prevalence rates ranging between 30 and 35%. Multifactorial variables play a pathogenic role in the high comorbid occurrence of these two disorders. These variables were critically examined during an international symposium held in Chicago in September 2010, the results of which are presented in two companion manuscripts. The first manuscript summarizes new epidemiologic data highlighting the bidirectional relation between depression and epilepsy and related methodological issues in studying this relationship. An examination of the neurobiologic aspects of primary mood disorders, mood disorders in PWE and pathogenic mechanisms of epilepsy derived from studies in animal models and humans is allowing a better understanding of the complex relation between the two conditions. In the first manuscript, we review data from animal models of epilepsy in which equivalent symptoms of depression and anxiety disorders develop and, conversely, animal models of depression in which the kindling process is facilitated. Data from structural and functional neuroimaging studies in humans provide a further understanding of potential common pathogenic mechanisms operant in depression and epilepsy that may explain their high comorbidity. The negative impact of depression on the control of seizure disorders has been documented in various studies. In this manuscript, these data are reviewed and potential mechanisms explaining this phenomenon are proposed.

Depression in patients with refractory temporal lobe epilepsy

OBJECTIVE

To evaluate the comorbidity of depressive disorders in patients with refractory temporal lobe epilepsy (TLE).

METHOD

We evaluated 25 consecutive patients with refractory TLE (16 women and 9 men), using semi-structured psychiatric interviews, according to the International Classification of Diseases (ICD-10), and the Beck Depression Inventory.

RESULTS

Seventeen of 25 patients (68%) had depressive disorder: 6 with dysthymia, three with major depressive episodes and 8 with recurrent depressive disorders. Two (8%) were diagnosed with mixed anxiety and depression. Only 5 of 17 patients (29.4%) were previously diagnosed with depressive disorder and received prior antidepressant treatment. Duration of epilepsy was significantly higher in patients with depressive disorder (p=0.016), but there was no relationship between depression and seizure frequency.

CONCLUSION

This study confirmed that depressive disorders are common and underdiagnosed in patients with TLE refractory to AEDs. Patients with longer duration of epilepsy are at higher risk of having depression.

Is major depressive disorder specifically associated with mesial temporal sclerosis?

PURPOSE

Whether a specific lesion such as mesial temporal sclerosis (MTS) increases the risk for a mood disorder in epilepsy remains subject to debate. Despite evidence of limbic system involvement in the genesis of emotional symptoms, recent studies fail to support an association between depression and MTS. We aimed to clarify this controversial issue by overcoming prior methodologic limitations, hypothesizing that rates of major depressive disorder (MDD) would be higher in patients with MTS.

METHODS

Three hundred eight patients with focal epilepsy (International League Against Epilepsy [ILAE] criteria), were classified into three groups on the basis of neuroimaging findings: MTS, a lesion different from MTS, or absence of lesion. Patients were assessed using the Structured Interview for DSM-IV axis I psychiatric disorders (SCID-I), by a psychiatrist blinded to epilepsy subtype. The Spanish version of the Hospital Anxiety and Depression Scale (HADS) was also administered. A complete logistic regression analysis was performed to investigate the association between MTS and MDD.

KEY FINDINGS

MTS increased the likelihood of a lifetime MDD by nearly 2.5. No other current or "postseizure onset" lifetime Axis I DSM-IV psychiatric disorder was associated with MTS. Female gender, primary education, comorbid anxiety disorders, and antidepressant treatment were also associated with an increased risk of MDD. Marriage was found to be a protective factor for MDD.

SIGNIFICANCE

Our results support a specific association between MTS and lifetime "postseizure onset," MDD. The lack of association with current depression is in line with the hypothesis that the link between MTS and depression is more of a chronic than a state-dependent condition.

Cortical thickness abnormalities associated with depressive symptoms in temporal lobe epilepsy

Depression in patients with temporal lobe epilepsy (TLE) is highly prevalent and carries significant morbidity and mortality. Its neural basis is poorly understood. We used quantitative, surface-based MRI analysis to correlate brain morphometry with severity of depressive symptoms in 38 patients with TLE and 45 controls. Increasing severity of depressive symptoms was associated with orbitofrontal cortex (OFC) thinning in controls, but with OFC thickening in TLE patients. These results demonstrate distinct neuroanatomical substrates for depression with and without TLE, and suggest a unique role for OFC, a limbic region for emotional processing strongly interconnected with medial temporal structures, in TLE-related depressive symptoms.

Benign rolandic epileptiform discharges are associated with mood and behavior problems

Children with benign rolandic epilepsy (BRE) experience elevated rates of cognitive, behavioral, and affective problems. Frequent epileptiform spike discharges may impair behavioral functioning. To elucidate this relationship, we evaluated associations between the EEG spike frequency index (SI) and parental ratings of psychosocial adjustment and executive functioning in school-aged children with EEGs typical of BRE. Twenty-one children (6-12 years) participated. Parents completed validated questionnaires at a median of 5 months (range: 1-8) after a routine outpatient EEG. The EEG SI was calculated for wakefulness and sleep. The strength of association between the SI and behavioral variables was evaluated by simple and multivariate correlation. Higher awake and sleep SIs were associated with more symptoms of depression (P<0.001), aggression and conduct problems (P<0.01). Higher sleep SI was associated with executive dysfunction and anxiety (P<0.05). Symptoms of hyperactivity and inattention had no correlation. Increased epileptiform activity in children with BRE may predict higher rates of mood and behavioral problems.

Lamotrigine improves aggression in patients with temporal lobe epilepsy

Aggression in patients with temporal lobe epilepsy (TLE) may have phenomenological and neurobiological heterogeneity. In the present study, we targeted patients with TLE who showed aggression and evaluated the effects of lamotrigine on this symptom using the Buss-Perry Aggression Questionnaire (BAQ), which is based on a four-factor model that includes Physical Aggression, Verbal Aggression, Anger, and Hostility. As compared with the healthy control subjects (n=115), patients with TLE (n=21) had significantly higher BAQ Total, Physical Aggression, Anger, and Hostility scores. Ten weeks after initiation of lamotrigine, the BAQ Total and Anger scores of the patients with TLE were significantly improved. However, the patients with TLE in this study did not exhibit depressive symptoms. Our results suggest that lamotrigine mitigates aggression, especially anger, which represents the emotional factor of aggression in the BAQ.

Diurnal variations in depression-like behavior of Wistar and spontaneously hypertensive rats in the kainate model of temporal lobe epilepsy

The purpose of this study was to explore whether the kainate (KA) model of temporal lobe epilepsy (TLE) can be used as a model of comorbid epilepsy and depression to study diurnal behavioral variations in rats. Development of chronic epilepsy was confirmed by the detection of spontaneous motor seizures (SMS) with video monitoring (24 hours/3-5 months after status epilepticus [SE]). KA-treated spontaneously hypertensive rats (SHRs) exhibited higher seizure frequency than Wistar rats during the light phase in the fourth and fifth months after SE. Although epileptic Wistar rats showed depression-like behavior and reduced anxiety mostly during the light phase, there were no diurnal variations in depression-like patterns in SHRs. Anxiety levels of control and epileptic SHRs were similar. Decreases in serotonin, tryptophan, and dopamine concentrations in the hippocampus were detected in epileptic Wistar rats compared with naive controls. However, monoamine levels of epileptic SHRs were close to those of their controls. Wistar rats and SHRs develop stable depression-like behavior during the chronic epileptic phase with strain-dependent diurnal differences.

Bilateral hippocampal atrophy in temporal lobe epilepsy: effect of depressive symptoms and febrile seizures

PURPOSE

Neuroimaging studies suggest a history of febrile seizures, and depression, are associated with hippocampal volume reductions in patients with temporal lobe epilepsy (TLE).

METHODS

We used radial atrophy mapping (RAM), a three-dimensional (3D) surface modeling tool, to measure hippocampal atrophy in 40 patients with unilateral TLE, with or without a history of febrile seizures and symptoms of depression. Multiple linear regression was used to single out the effects of covariates on local atrophy.

KEY FINDINGS

Subjects with a history of febrile seizures (n =15) had atrophy in regions corresponding to the CA1 and CA3 subfields of the hippocampus contralateral to seizure focus (CHC) compared to those without a history of febrile seizures (n = 25). Subjects with Beck Depression Inventory II (BDI-II) score ≥ 14 (n = 11) had atrophy in the superoanterior portion of the CHC compared to subjects with BDI-II <14 (n = 29).

SIGNIFICANCE

Contralateral hippocampal atrophy in TLE may be related to febrile seizures or depression.

Why mesial temporal lobe epilepsy with hippocampal sclerosis is progressive: uncontrolled inflammation drives disease progression?

Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE-HS) is a group of chronic disorders characterized by prominent neuronal loss and gliosis in the hippocampus and amygdala. Newly published data indicate that it may be a progressive disease, but the mechanism underlying the progressive nature remains unknown. Recently, substantial evidence for an inflammatory mechanism in MTLE has been documented. We are therefore presenting a review of literature concerning the effects of uncontrolled inflammation on the disease progression of MTLE-HS. We found that increasing amounts of evidence support the association between uncontrolled inflammation and progression of the disease. Uncontrolled inflammatory processes may be a main mechanism underlying the self-propagating cycle of uncontrolled inflammation, blood-brain barrier damage, and seizures that drive the progressive nature. Thus it is important to unravel the principles of communication between the different factors in this cycle. The dynamic modulation of inflammatory processes aimed at preventing or interrupting this cycle has the potential to emerge as a novel therapeutic strategy. This line of therapy might offer new perspectives on the pharmacologic treatment of seizures, and possibly on delaying disease progression or retarding epileptogenesis as well.

Suicidality and brain volumes in pediatric epilepsy

This study examined the relationship between suicidal ideation and frontotemporal volumes, particularly orbital frontal gyrus volume, in 51 subjects with epilepsy with a mean age of 9.8 (2.1) years. Structured psychiatric interviews of the children and parents provided information on suicidal behavior and DSM-IV diagnoses. Tissue of 1.5-T MRI scans was segmented, and total brain, frontal lobe, frontal parcellations, and temporal lobe volumes were computed. The 11 subjects with epilepsy with suicidal ideation had significantly smaller right orbital frontal gyrus white matter volumes and larger left temporal lobe gray matter volumes than the 40 children without suicidal thoughts. Given the role of the orbital frontal gyrus in both emotional regulation and epilepsy, these findings highlight the biological underpinnings of suicidal ideation in pediatric epilepsy.

Prevalence of interictal psychiatric disorders in patients with refractory temporal and extratemporal lobe epilepsy in Spain. A comparative study

We aim to investigate whether temporal origin of epilepsy increases the risk of developing a psychiatric disorder and more specifically a major depressive disorder. The lack of standardized diagnostic instruments and the methodologic differences between studies highlight the fact that this issue warrants further, systematic, study. Three-hundred eight patients with complex partial seizures were classified according to temporal or extratemporal origin, following the Commission on Classification and Terminology of the International League Against Epilepsy (ILAE), 1989 localization-related concept. All patients were assessed using the Structured Interview for DSM-IV axis I psychiatric disorders (SCID-I). Lifetime and previous-year prevalence of psychiatric disorders were compared in temporal and extratemporal subgroups, using multivariate analysis. Previous-year major depression was significantly associated with temporal lobe origin. Our results do not support the hypothesis that patients with temporal lobe epilepsy (TLE) have more psychiatric illness in general, although they do suggest a specific connection between TLE and major depression.