Brian Bell

Psychiatric Comorbidity in Chronic Epilepsy: Identification, Consequences, and Treatment of Major Depression

Summary: The purpose of this article is to review the topic of interictal psychiatric comorbidity among adult patients with chronic epilepsy, focusing specifically on those studies that have used contemporary psychiatric nosology. Five specific issues are addressed: (a) the risk and predominant type(s) of psychiatric comorbidity in chronic epilepsy, (b) adequacy of recognition and treatment of psychiatric comorbidity, (c) the additional burdens that comorbid psychiatric disorders impose upon patients with chronic epilepsy, (d) the etiology of these disorders, and (e) strategies for treatment. Current appreciation for these issues in epilepsy is contrasted to related fields (e.g., primary care, psychiatry, and epidemiology), where considerable attention has been devoted to the identification, consequences, and treatment of psychiatric comorbidity. The issue of psychiatric comorbidity in epilepsy is reviewed with the aim of identifying a clinical and research agenda that will advance understanding of at least one important psychiatric condition associated with epilepsy—namely, major depression.

The nature and course of neuropsychological morbidity in chronic temporal lobe epilepsy

Objective: To characterize the nature and degree of cognitive morbidity in patients with chronic temporal lobe epilepsy compared with healthy control subjects, determine the association between the duration of epilepsy and cognitive morbidity, and ascertain whether there are factors that moderate the association between duration of disorder and cognitive impairment. Methods: Temporal lobe epilepsy (n = 96) and healthy control (n = 82) subjects were assessed with a comprehensive neuropsychological battery. Test performances were adjusted for age, gender, and education and transformed to a common metric (z scores). Analyses included group comparisons and correlations of duration of epilepsy with cognitive morbidity. Results: Patients with temporal lobe epilepsy exhibited not only worse memory function (p < 0.05) but worse performance across measures of intelligence, language, executive function, and motor speed (p < 0.05). Chronicity of epilepsy was related to worsening mental status (r = 0.42, p < 0.001). This relationship was particularly evident among those individuals with less (r = 0.58, p < 0.001) compared with more (r = 0.25, NS) cerebral reserve, operationally defined by years of formal education. Conclusions: Neuropsychological morbidity in chronic temporal lobe epilepsy is widespread in nature despite a focal epileptic process. Cross-sectional analyses demonstrate that increasing duration of epilepsy is associated with worsening mental status. Individuals with less educational attainment (low cerebral reserve) exhibit especially poor cognitive function in association with chronicity of epilepsy.

The Neurodevelopmental Impact of Childhood‐onset Temporal Lobe Epilepsy on Brain Structure and Function

Summary:  Purpose: To characterize the neurodevelopmental correlates of childhood‐onset temporal lobe epilepsy on brain structure and cognition compared with late‐onset chronic temporal lobe epilepsy and healthy controls.

Cognitive prognosis in chronic temporal lobe epilepsy

First, to determine whether patients with chronic temporal lobe epilepsy have a different cognitive trajectory compared to control subjects over a prospective 4‐year interval; second, to determine the proportion of patients who exhibit abnormal cognitive change and their profile of demographic, clinical epilepsy, and baseline quantitative magnetic resonance imaging characteristics; and third, to determine the most vulnerable cognitive domains.

The neurobiology of cognitive disorders in temporal lobe epilepsy

Cognitive impairment, particularly memory disruption, is a major complicating feature of epilepsy. This Review will begin with a focus on the problem of memory impairment in temporal lobe epilepsy (TLE). We present a brief overview of anatomical substrates of memory disorders in TLE, followed by a discussion of how our understanding of these disorders has been improved by studying the outcomes of anterior temporal lobectomy. The clinical efforts made to predict which patients are at greatest risk of experiencing adverse cognitive outcomes following epilepsy surgery are also considered. Finally, we examine the vastly changing view of TLE, including findings demonstrating that anatomical abnormalities extend far outside the temporal lobe, and that cognitive impairments extend beyond memory function. Linkage between these distributed cognitive and anatomical abnormalities point to a new understanding of the anatomical architecture of cognitive impairment in epilepsy. Clarifying the origin of these cognitive and anatomical abnormalities, their progression over time and, most importantly, methods for protecting cognitive and brain health in epilepsy, present a challenge to neurologists.

The neurodevelopmental impact of childhood onset temporal lobe epilepsy on brain structure and function and the risk of progressive cognitive effects.

The purpose of this study is to explore the possibility of progressive neuropsychological decline in chronic temporal lobe epilepsy (TLE) and determine how this vulnerability may be associated with the neurodevelopmental impact of the disorder. 53 patients with TLE and 62 healthy controls underwent quantitative MRI volumetric imaging of total brain tissue and hippocampal volumes as well as assessment of intelligence and memory function. In addition to reduced hippocampal volume, childhood onset (< 14 years) but not adult onset TLE was associated with significantly reduced total brain tissue that was generalized in nature and extended into extratemporal regions. In addition to this adverse impact on brain structure, there was significantly reduced intellectual status as well as memory function in childhood onset TLE patients, consistent with the generalized nature of the MRI volumetric abnormalities. Finally, cross-sectional correlational analyses indicated that increasing duration of epilepsy in childhood onset patients was associated with declining performance across both intellectual and memory measures, suggestive of progressive cognitive effects. We propose that childhood onset TLE is associated with an adverse neurodevelopmental impact on brain structure and function which represents an early acquired vulnerability, effectively reducing cerebral reserve, placing patients at risk for progressive cognitive decline in the context of chronic and unremitting epilepsy.

Recognition and identification of famous faces in patients with unilateral temporal lobe epilepsy

We examined the performance of 21 patients with unilateral temporal lobe epilepsy (TLE) and hippocampal damage (10 lefts, and 11 rights) and 10 age-matched controls on the recognition and identification (name and occupation) of well-known faces. Famous face stimuli were selected from four time periods; 1970s, 1980s, 1990-1994, and 1995-1996. Differential patterns of performance were observed for the left and right TLE group across distinct face processing components. The left TLE group showed a selective impairment in naming famous faces while they performed similar to the controls in face recognition and semantic identification (i.e. occupation). In contrast, the right TLE group was impaired across all components of face memory; face recognition, semantic identification, and face naming. Face naming impairment in the left TLE group was characterized by a temporal gradient with better naming performance for famous faces from more distant time periods. Findings are discussed in terms of the role of the temporal lobe system for the acquisition, retention, and retrieval of face semantic networks, and the differential effects of lateralized temporal lobe lesions in this process.

Confrontation naming after anterior temporal lobectomy is related to age of acquisition of the object names.

Decline in visual confrontation naming ability may occur as a postacute complication of left anterior temporal lobectomy (ATL) for the treatment of intractable mesial temporal lobe epilepsy. In this study of 26 left ATL patients who demonstrated postsurgery decline on a standardized naming measure, it was hypothesized that naming performance would be significantly associated with specific attributes of the object names. We investigated the relation between performance on the Boston Naming Test (BNT) and the following attributes of the test items: living versus nonliving category (L/NL), word length (WL), written word frequency (WF), and age of acquisition (AoA). Regression analyses revealed that AoA and WF were significant predictors of preoperative group performance. AoA was the only significant predictor of performance after left ATL. For the 17 individuals who demonstrated a statistically meaningful decline on the BNT, as indicated by a Reliable Change Index, individual logistic regressions demonstrated that AoA was the strongest and most consistent predictor of postoperative success/failure for items that had been named correctly preoperatively. Consistent with the literature on naming errors in elderly normals and patients with aphasia or semantic dementia, the results provide evidence that object names learned in late childhood are among the most vulnerable when there is a decline in object naming ability. Investigation of additional attributes and semantic knowledge for the concepts represented by the pictured objects will be necessary to determine whether the naming deficit associated with TLE and ATL reflects an impairment of phonological word-form retrieval, semantics, or both.

Extratemporal quantitative MR volumetrics and neuropsychological status in temporal lobe epilepsy.

Neuropsychological studies of temporal lobe epilepsy have focused heavily on the nature and extent of memory dysfunction and its relationship to the neuropathological status of the hippocampus and related mesial temporal lobe structures. In this study, we examined whole brain and lobar quantitative MRI volumes and comprehensive neuropsychological performance in 58 patients with temporal lobe epilepsy and 62 healthy controls in order to determine (1) the nature and degree of extratemporal structural abnormalities in localization-related temporal lobe epilepsy: (2) the nature and degree of cognitive abnormalities outside of anterograde memory function; and (3) the relationship of volumetric abnormalities to neuropsychological status. Temporal lobe epilepsy patients exhibited significant reduction in the volume of adjusted (age, gender, height) total cerebral tissue (-5.8%), more evident in white (-9.8%) compared to gray matter (-3.0%) tissue volumes. Significant volumetric reductions were evident across frontal, temporal and parietal but not occipital lobe regions. Subarachnoid but not total ventricular CSF was significantly increased in epilepsy patients. Neuropsychological abnormality was generalized in nature, consistent with the generalized nature of the morphometric abnormalities, and reductions in cerebral tissue volumes were directly associated with poorer cognitive performance. In summary, patients with temporal lobe epilepsy exhibited clinically significant structural and functional abnormalities that extended outside the epileptogenic temporal lobe. The degree to which these structural and cognitive abnormalities are due to factors that cause the epilepsy, as opposed to reflecting the consequences of chronic epilepsy (e.g., duration and severity of epilepsy), remain to be determined.

Comorbid Psychiatric Symptoms in Temporal Lobe Epilepsy: Association with Chronicity of Epilepsy and Impact on Quality of Life

Purpose. The goals of this work were to determine: (1) the nature and extent of differences in self-reported psychiatric symptoms between patients with temporal lobe epilepsy and matched healthy controls, (2) the relationship between chronicity (duration) of temporal lobe epilepsy and comorbid interictal psychiatric symptoms, and (3) the impact of comorbid psychiatric symptoms on self-reported health-related quality of life. Methods. Patients with temporal lobe epilepsy (n = 54) and healthy controls (n = 38) were administered the Symptom Checklist-90-Revised (SCL-90-R) to assess the nature and severity of psychiatric symptomatology and epilepsy patients completed the Quality of Life in Epilepsy-89 (QOLIE-89) to define health-related quality of life. Among epilepsy patients the SCL-90-R scales were examined in relation to chronicity of temporal lobe epilepsy as well as the impact of comorbid emotional-behavioral distress on health-related quality of life. Results. Compared with healthy controls, patients with epilepsy exhibited significantly higher (worse) scores across all but one of the 12 SCL-90-R scales. Among patients with epilepsy, increasing chronicity was associated with significantly higher (worse) scores across all SCL-90-R scales and increased emotional-behavioral distress was associated with lower (worse) scores across all 17 QOLIE-89 scales. Conclusion. Comorbid interictal psychiatric symptoms are elevated among patients with temporal lobe epilepsy compared with healthy controls and appear to be modestly associated with increasing chronicity (duration) of epilepsy. This comorbid emotional-behavioral distress is specifically associated with a significantly poorer health-related quality of life, and suggests that quality-of-life research should devote greater attention to the potential impact of comorbid psychiatric distress.