Emotion recognition and social cognition in temporal lobe epilepsy and the effect of epilepsy surgery

The abilities to identify facial expression from another person's face and to attribute mental states to others refer to preserved function of the temporal lobes. In the present study, we set out to evaluate emotion recognition and social cognition in presurgical and postsurgical patients with unilateral refractory temporal lobe epilepsy (TLE). The aim of our study was to investigate the effects of TLE surgery and to identify the main risk factors for impairment in these functions.We recruited 30 patients with TLE for longitudinal data analysis (14 with right-sided and 16 with left-sided TLE) and 74 patients for cross-sectional data analysis (37 with right-sided and 37 with left-sided TLE) plus 20 healthy controls. Besides standard neuropsychological assessment, we administered an analog of the Ekman and Friesen test and the Faux Pas Test to assess emotion recognition and social cognition, respectively.Both emotion recognition and social cognition were impaired in the group of patients with TLE, irrespective of the focus side, compared with healthy controls. The performance in both tests was strongly dependent on the intelligence level. Beyond intelligence level, earlier age at epilepsy onset, longer disease duration, and history of early childhood brain injury predicted social cognition problems in patients with TLE. Epilepsy surgery within the temporal lobe seems to have neutral effect on patients' performances in both domains. However, there are a few individual patients who appear to be at risk of postoperative decline, even when seizure freedom is achieved following epilepsy surgery.     

Investigation of social and emotion information processing in temporal lobe epilepsy with ictal fear

This study examined whether patients with temporal lobe epilepsy (TLE) and ictal fear (IF) show emotion recognition deficits similar to those associated with amygdala damage. Three groups of patients (13 with TLE and IF, 14 with TLE and nonfear auras (non-IF), and 10 with idiopathic generalized epilepsy (IGE)) completed tests of visual and face processing, face emotion recognition and social judgment, together with measures of psychological adjustment (Hospital Anxiety and Depression Scale; SCL-90-R) and Quality of Life (QOLIE-31). All three epilepsy groups had fear recognition deficits, with relatively greater impairments in the IF group. Fear recognition deficits were associated with impaired social judgment of trustworthiness, duration of epilepsy, and a measure of quality of life. Social cognition impairments previously associated with amygdala dysfunction are also a feature of the neuropsychology of TLE, and extend the hypothesis in that they may additionally play a role in IGE.     

Facial emotion recognition impairment in chronic temporal lobe epilepsy

Purpose:   To evaluate facial emotion recognition (FER) in a cohort of 176 patients with chronic temporal lobe epilepsy (TLE).
Methods:   FER was tested by matching facial expressions with the verbal labels for the following basic emotions: happiness, sadness, fear, disgust, and anger. Emotion recognition performances were analyzed in medial (n = 140) and lateral (n = 36) TLE groups. Fifty healthy subjects served as controls. The clinical and neuroradiologic variables potentially affecting the ability to recognize facial expressions were taken into account.
Results:   The medial TLE (MTLE) group showed impaired FER (86% correct recognition) compared to both the lateral TLE patients (FER = 93.5%) and the controls (FER = 96.4%), with 42% of MTLE patients recording rates of FER that were lower [by at least 2 standard deviations (SDs)] than the control mean. The MTLE group was impaired compared to the healthy controls in the recognition of all basic facial expressions except happiness. The patients with bilateral MTLE were the most severely impaired, followed by the right and then the left MTLE patients. FER was not affected by type of lesion, number of antiepileptic drugs (AEDs), aura semiology, or gender. Conversely, the early onset of seizures/epilepsy was related to FER deficits. These deficits were already established in young adulthood, with no evidence of progression in older MTLE patients.
Conclusion:   These results on a large cohort of TLE patients demonstrate that emotion recognition deficits are common in MTLE patients and widespread across negative emotions. We confirm that early onset seizures with right or bilateral medial temporal dysfunction lead to severe deficits in recognizing facial expressions of emotions.     

Social cognition in temporal lobe epilepsy: A systematic review and meta-analysis

ObjectiveThere is increasing evidence suggesting that social cognitive abilities are impaired in temporal lobe epilepsy (TLE), the most common form of focal epilepsies.MethodsIn this meta-analysis, 31 studies investigating theory of mind (ToM) and facial emotion recognition performances of 1356 patients with TLE (351 postsurgery) and 859 healthy controls were included.ResultsPatients with TLE had significant deficits in ToM (d = 0.73–0.89) and recognition of facial emotions. There were no significant differences in severity of social cognitive deficits between patients with TLE with or without medial temporal lobectomy. Earlier onset of seizures was associated with ToM impairment. Right-sided TLE was associated with more severe deficits in recognition of fear, sadness, and disgust.ConclusionsSocial cognitive information processing is impaired in TLE, and the potential role of these deficits in functional impairment needs to be further investigated.     

Social cognition dysfunctions in patients with epilepsy: Evidence from patients with temporal lobe and idiopathic generalized epilepsies

Background and aimDespite an extensive literature on cognitive impairments in focal and generalized epilepsy, only a few number of studies specifically explored social cognition disorders in epilepsy syndromes. The aim of our study was to investigate social cognition abilities in patients with temporal lobe epilepsy (TLE) and in patients with idiopathic generalized epilepsy (IGE).Materials and methodsThirty-nine patients (21 patients with TLE and 18 patients with IGE) and 21 matched healthy controls (HCs) were recruited. All subjects underwent a basic neuropsychological battery plus two experimental tasks evaluating emotion recognition from facial expression (Ekman-60-Faces test, Ek-60F) and mental state attribution (Story-based Empathy Task, SET). In particular, the latter is a newly developed task that assesses the ability to infer others' intentions (i.e., intention attribution — IA) and emotions (i.e., emotion attribution — EA) compared with a control condition of physical causality (i.e., causal inferences — CI).ResultsCompared with HCs, patients with TLE showed significantly lower performances on both social cognition tasks. In particular, all SET subconditions as well as the recognition of negative emotions were significantly impaired in patients with TLE vs. HCs. On the contrary, patients with IGE showed impairments on anger recognition only without any deficit at the SET task.DiscussionEmotion recognition deficits occur in patients with epilepsy, possibly because of a global disruption of a pathway involving frontal, temporal, and limbic regions. Impairments of mental state attribution specifically characterize the neuropsychological profile of patients with TLE in the context of the in-depth temporal dysfunction typical of such patients.ConclusionImpairments of socioemotional processing have to be considered as part of the neuropsychological assessment in both TLE and IGE in view of a correct management and for future therapeutic interventions.     

Emotion recognition in temporal lobe epilepsy: A systematic review

There is increasing interest in the understanding of emotion recognition deficits in temporal lobe epilepsy (TLE), the most common form of focal epilepsies. There are conflicting reports about impairments for different emotions in right and left temporal lobe epilepsy patients. A systematic review and a narrative synthesis was conducted for studies investigating emotion recognition (ER) in TLE. Embase, MEDLINE, PsychINFO and Pubmed were searched from 1990 to March 2015 and reference lists were reviewed. 996 citations were identified and 43 studies were finally included.ER deficits are consistently observed across studies. A fear recognition deficit is always reported, followed by deficits in sadness and disgust recognition. Deficits are observed across visual and auditory domains. Conflicting evidence is present concerning the severity of ER deficits in right and left TLE. Studies on anterior temporal lobectomy report data similar to that observed in pre-surgical patients.Current evidence supports the conclusion that recognition of negative emotions is commonly impaired in TLE, particularly for fear, and in the visual domain. Future work should focus on more ecologically valid test, on longitudinal studies to assess the role of anterior temporal lobectomy, and to correlate ER measures to social functioning in everyday life.     

Visual and auditory socio‐cognitive perception in unilateral temporal lobe epilepsy in children and adolescents: a prospective controlled study

Aim. A high rate of abnormal social behavioural traits or perceptual deficits is observed in children with unilateral temporal lobe epilepsy. In the present study, perception of auditory and visual social signals, carried by faces and voices, was evaluated in children or adolescents with temporal lobe epilepsy. Methods. We prospectively investigated a sample of 62 children with focal non‐idiopathic epilepsy early in the course of the disorder. The present analysis included 39 children with a confirmed diagnosis of temporal lobe epilepsy. Control participants (72), distributed across 10 age groups, served as a control group. Our socio‐perceptual evaluation protocol comprised three socio‐visual tasks (face identity, facial emotion and gaze direction recognition), two socio‐auditory tasks (voice identity and emotional prosody recognition), and three control tasks (lip reading, geometrical pattern and linguistic intonation recognition). All 39 patients also benefited from a neuropsychological examination. Results. As a group, children with temporal lobe epilepsy performed at a significantly lower level compared to the control group with regards to recognition of facial identity, direction of eye gaze, and emotional facial expressions. We found no relationship between the type of visual deficit and age at first seizure, duration of epilepsy, or the epilepsy‐affected cerebral hemisphere. Deficits in socio‐perceptual tasks could be found independently of the presence of deficits in visual or auditory episodic memory, visual non‐facial pattern processing (control tasks), or speech perception. A normal FSIQ did not exempt some of the patients from an underlying deficit in some of the socio‐perceptual tasks. Conclusion. Temporal lobe epilepsy not only impairs development of emotion recognition, but can also impair development of perception of other socio‐perceptual signals in children with or without intellectual deficiency. Prospective studies need to be designed to evaluate the results of appropriate re‐education programs in children presenting with deficits in social cue processing.     

Impaired facial expression recognition in children with temporal lobe epilepsy: impact of early seizure onset on fear recognition

The amygdala has been implicated in the recognition of facial emotions, especially fearful expressions, in adults with early-onset right temporal lobe epilepsy (TLE). The present study investigates the recognition of facial emotions in children and adolescents, 8–16 years old, with epilepsy. Twenty-nine subjects had TLE (13 right, 16 left) and eight had fronto-central epilepsy (FCE). Each was matched on age and gender with a control subject. Subjects were asked to label the emotions expressed in pictures of children's faces miming five basic emotions (happiness, sadness, fear, disgust and anger) or neutrality (no emotion). All groups of children with epilepsy performed less well than controls. Patterns of impairment differed according to the topography of the epilepsy: the left-TLE (LTLE) group was impaired in recognizing fear and neutrality, the right-TLE (RTLE) group was impaired in recognizing disgust and, the FCE group was impaired in recognizing happiness. We clearly demonstrated that early seizure onset is associated with poor recognition of facial expression of emotion in TLE group, particularly for fear. Although right-TLE and left-TLE subjects were both impaired in the recognition of facial emotion, their psychosocial adjustment, as measured by the CBCL questionnaire [Achenbach, T. M. (1991). Manual for the Child Behavior Checklist and Youth Self-report. Burlington, VT: University of Vermont Department of Psychiatry], showed that poor recognition of fearful expressions was related to behavioral disorders only in children with right-TLE. Our study demonstrates for the first time that early-onset TLE can compromise the development of recognizing facial expressions of emotion in children and adolescents and suggests a link between impaired fear recognition and behavioral disorders.     

Theory of mind in frontal and temporal lobe epilepsy: cognitive and neural aspects

Purpose: Theory of mind (ToM) is an important prerequisite to social behavior. This study evaluated ToM in patients with temporal (TLE) or frontal lobe epilepsy (FLE) aiming to determine the cognitive aspects, severity, and pathophysiologic mechanisms of ToM impairment in focal epilepsy. Methods: One hundred thirty‐eight patients with TLE (n = 109) or FLE (n = 29) and 69 healthy subjects underwent the Faux Pas task (FPT), which evaluates the recognition and comprehension of others’ mental states, and neuropsychological tests for other cognitive functions. Key Findings: Factor analysis of all test scores yielded two ToM factors (Recognizing faux pas, FP; Excluding nonexistent FP) distinct from the Control, Language, Matching, and Praxis factors. With respect to healthy subjects, both TLE and FLE patients showed correct exclusion of nonexistent FPs but significantly lower recognition and comprehension of real FPs. FLE patients were also impaired with respect to TLE patients. In the whole patient group, schooling and group membership predicted ToM impairment. In FLE patients, the comprehension of mental states was predicted by disease duration, whereas TLE patients’ comprehension of affects and intentions was associated with early age of seizure onset and medial temporal lobe sclerosis (MTLS). Significance: Focal epilepsy impairs advanced ToM abilities. FLE may affect online performances owing to long‐lasting dysfunctions of the prefrontal areas. MTLS may provoke selective ToM deficits due to medial temporal damage, prefrontal dysfunctions, or early interference with cognitive development. Future studies are needed to determine the implications of ToM impairment on behavior and quality of life.     

Face memory in MRI-positive and MRI-negative temporal lobe epilepsy

PURPOSE: Effects of MRI-positive (MRI(+)) as compared to MRI-negative (MRI(-)) temporal lobe epilepsy (TLE) on face memory are not yet known. METHODS: We studied 24 MRI(-) (11 right/13 left) and 20 MRI(+) (13 right/7 left) TLE patients, 12 generalized epilepsy patients, and 12 healthy subjects undergoing diagnostic workup with 24-72-h Video-EEG-monitoring. Twenty faces were shown, and had to be recognized from 40 faces immediately and after a 24-h delay. RESULTS: MRI(+) and MRI(-) right TLE (RTLE) patients showed deficits in face recognition compared to controls or generalized epilepsy, consistent with right temporal lobe dominance for face recognition. MRI(+) RTLE patients had deficits in both immediate and delayed recognition, while MRI(-) RTLE patients showed delayed recognition deficits only. The RTLE groups showed comparable delayed recognition deficits. Separate analyses in which the MRI(+) group included patients with hippocampal sclerosis only, did not alter results. Furthermore, MRI(-) RTLE had a worse delayed recognition than MRI(-) left TLE (LTLE). On the other hand, MRI(+) RTLE did not differ from MRI(+) LTLE in delayed recognition. Combining MRI(-) and MRI(+) TLE groups, we found differences between RTLE and LTLE in delayed, but not immediate face recognition. CONCLUSIONS: Our results suggest that a delayed recognition condition might be superior to immediate recognition tests in detecting face memory deficits in MRI(-) RTLE patients. This might explain why former studies in preoperative patients did not observe an immediate face recognition dominance of the right temporal lobe when combining MRI(-) and MRI(+) TLE patients. Our data further point to an important role of the right mesial temporal region in face recognition in TLE.     

Impaired fear processing in right mesial temporal sclerosis: a fMRI study

Lesion and neuroimaging studies have demonstrated that the mesial temporal lobe is crucial for recognizing emotions from facial expressions. In humans, bilateral amygdala damage is followed by impaired recognition of facial expressions of fear. To evaluate the influence of unilateral mesial temporal lobe damage we examined recognition of facial expressions and functional magnetic resonance (fMRI) brain activation associated with incidental processing of fearful faces in thirteen mesial temporal lobe epilepsy (MTLE) patients (eight with right MTLE, five with left MTLE). We also examined the effect of early versus later damage, comparing subjects with hippocampal-amygdalar sclerosis (MTS) and seizures occurring before five years of age to epilepsy patients with late onset seizures. Fourteen healthy volunteers participated as controls. Neuropsychological testing demonstrated that the ability of right MTLE patients to recognize fearful facial expressions is impaired. Patients with early onset of seizures were the most severely impaired. This deficit was associated with defective activation of a neural network involved in the processing of fearful expressions, which in controls and left MTLE included the left inferior frontal cortex and several occipito-temporal structures of both hemispheres.     

Emotion recognition, 'theory of mind,' and social behavior in schizophrenia

Several studies have demonstrated that patients with schizophrenia are impaired in recognizing emotions from facial expressions and in appreciating other people's mental states--the latter commonly referred to as 'theory of mind.' The question as to how social cognitive skills relate to patients' actual social behavior is, however, largely unanswered. This study examined emotion recognition, 'theory of mind,' and social behavior in schizophrenia. Emotion recognition, 'theory of mind,' executive functioning, 'crystallized' verbal intelligence, psychopathology, and social behavior were assessed in patients with schizophrenia compared with a healthy control group. Patients were significantly impaired on all tasks involving executive functioning, emotion recognition, and 'theory of mind.' Impaired executive functioning did, however, only partially account for the deficits in social perception and social cognition. Social perception and cognition in schizophrenia predicted the odds of being a patient significantly better than nonsocial cognition. Severe social behavioral abnormalities were linked to the duration of the illness, and even more so to 'theory of mind' deficits. Considering impaired social perception and social cognition significantly contributes to the understanding of social behavioral problems in schizophrenia.     

Amygdala lesion in temporal lobe epilepsy subjects impairs associative learning of emotional facial expressions

To investigate the role of unilateral amygdala lesions on processing emotions, 22 drug-resistant temporal lobe epilepsy (TLE) subjects (12 with left-sided and ten with right-sided focus) were tested, after anterior temporal lobectomy or selective amygdalo-hippocampectomy on two associative learning tasks containing emotional and neutral facial expressions, respectively. Volumetric lesion analysis was performed on the basis of 3-D MR images. No effects of lesion side were found in TLE subjects. Taken the extent of amygdala damage into account, an interaction effect could be shown between task (learning of neutral facial expressions versus emotional facial expressions) and group (subjects with little versus considerable amygdala damage), indicating worse performance of subjects with considerable amygdala damage in learning emotional facial expressions. Subjects with considerable amygdala damage were also significantly impaired in learning emotional facial expressions when compared with control subjects.     

Cognitive Outcomes in Patients with Chronic Temporal Lobe Epilepsy

Summary:  Cognitive impairment is frequent in temporal lobe epilepsy (TLE). In particular, specific deficits in temporal lobe related functions occur, but deficits in extratemporal lobe functions and global intelligence are also found. The degree and type of the impairment are first determined by structural damage and functionally dynamic factors. Most cognitive problems in TLE are already detectable at, or even before, the onset of the epilepsy. Accumulation of damage during the course of chronic epilepsy may add to this. This additional damage may be caused directly by severe seizures, head trauma, intoxication etc., or indirectly by interference of the epilepsy with mental development. Surgical treatment of TLE may also affect the cognitive outcome of patients with chronic TLE, with a risk of additional impairments on the one hand and functional recovery due to seizure control on the other hand. With regard to patient-associated factors, better baseline performance, younger age, cerebral plasticity, and good mental reserve capacities are associated with a better outcome. With regard to treatment-associated factors, prevention of additional brain dysfunction/damage and successful seizure control are important.     

Recognition of emotion with temporal lobe epilepsy and asymmetrical amygdala damage

PURPOSE: Impairments in emotion recognition occur when there is bilateral damage to the amygdala. In this study, ability to recognize auditory and visual expressions of emotion was investigated in people with asymmetrical amygdala damage (AAD) and temporal lobe epilepsy (TLE). METHODS: Recognition of five emotions was tested across three participant groups: those with right AAD and TLE, those with left AAD and TLE, and a comparison group. Four tasks were administered: recognition of emotion from facial expressions, sentences describing emotion-laden situations, nonverbal sounds, and prosody. RESULTS: Accuracy scores for each task and emotion were analysed, and no consistent overall effect of AAD on emotion recognition was found. However, some individual participants with AAD were significantly impaired at recognizing emotions, in both auditory and visual domains. CONCLUSIONS: The findings indicate that a minority of individuals with AAD have impairments in emotion recognition, but no evidence of specific impairments (e.g., visual or auditory) was found.     

Neuropsychological deficits in temporal lobe epilepsy: A comprehensive review

Temporal lobe epilepsy (TLE) is the most prevalent form of complex partial seizures with temporal lobe origin of electrical abnormality. Studies have shown that recurrent seizures affect all aspects of cognitive functioning, including memory, language, praxis, executive functions, and social judgment, among several others. In this article, we will review these cognitive impairments along with their neuropathological correlates in a comprehensive manner. We will see that neuropsychological deficits are prevalent in TLE. Much of the effort has been laid on memory due to the notion that temporal lobe brain structures involved in TLE play a central role in consolidating information into memory. It seems that damage to the mesial structure of the temporal lobe, particularly the amygdale and hippocampus, has the main role in these memory difficulties and the neurobiological plausibility of the role of the temporal lobe in different aspects of memory. Here, we will cover the sub-domains of working memory and episodic memory deficits. This is we will further proceed to evaluate the evidences of executive function deficits in TLE and will see that set-shifting among other EFs is specifically affected in TLE as is social cognition. Finally, critical components of language related deficits are also found in the form of word-finding difficulties. To conclude, TLE affects several of cognitive function domains, but the etiopathogenesis of all these dysfunctions remain elusive. Further well-designed studies are needed for a better understanding of these disorders.     

Risk factors for spatial memory impairment in patients with temporal lobe epilepsy

At present, the risk factors for world-centered (allocentric) navigation impairment in patients with temporal lobe epilepsy (TLE) are not known. There is some evidence on the importance of the right hippocampus but other clinical features have not been investigated yet. In this study, we used an experimental human equivalent to the Morris water maze to examine spatial navigation performance in patients with drug-refractory unilateral TLE. We included 47 left-hemisphere speech dominant patients (25 right sided; 22 left sided). The aim of our study was to identify clinical and demographic characteristics of TLE patients who performed poorly in allocentric spatial memory tests.Our results demonstrate that poor spatial navigation is significantly associated with younger age at epilepsy onset, longer disease duration, and lower intelligence level. Allocentric navigation in TLE patients was impaired irrespective of epilepsy lateralization. Good and poor navigators did not differ in their age, gender, or preoperative/postoperative status.This study provides evidence on risk factors that increase the likelihood of allocentric navigation impairment in TLE patients. The results indicate that not only temporal lobe dysfunction itself but also low general cognitive abilities may contribute to the navigation impairment.     

Elevated serum Bcl-2 in children with temporal lobe epilepsy

Intractable temporal lobe epilepsy (TLE) is associated with alterations in expression of apoptosis-associated signaling molecules in the temporal lobe. Bcl-2 is an anti-apoptotic molecule which has previously been reported to be raised in patient's brain and serum. In the present study we examined serum Bcl-2 protein levels as a surrogate marker of apoptosis-associated signaling in children with non lesional TLE. Serum Bcl-2 levels were found to be higher in patients with TLE than controls. The serum level correlated to seizure variables including, duration of disease, frequency of seizures, and disease severity. The impact of epilepsy on cognition was assessed using total score intelligence quotient (IQ). IQ was found to be lower than controls and negatively correlated to serum Bcl-2. These findings support serum Bcl-2 levels as a marker of seizure burden and cognition in children with epilepsy.     

"Tell me how do I feel"--emotion recognition and theory of mind in symptomatic mesial temporal lobe epilepsy

Specific interictal personality characteristics in epilepsy, sometimes referred to as "Waxman-Geschwind Syndrome", have been recognized for centuries and extensively described. Despite the persevering clinical impression that patients with mesial temporal lobe epilepsies (MTLE) suffer from problems in communication and interpersonal relations, uncertainties and controversies remain as to the precise origin of these psychosocial difficulties. Here, we investigated social-cognitive and decision-making abilities using a set of tasks that combine behavioural and psychological measures of social and emotional variables to answer the question of whether patients with MTLE are specifically impaired in social cognition compared to both an epilepsy and a healthy control group. MTLE patients, an epilepsy control group (extra-MTLE; patients with epilepsy, not originating within the frontal or mesial temporal lobe) and healthy controls (HC) were assessed according to their general cognitive status as well as with our Social Cognition Battery, which included tests of basic processes of social cognition, theory of mind, decision making, and various aspects of psychopathology and quality of life. MTLE patients were significantly impaired compared to HC on most measures of the Social Cognition Battery. MTLE patients were predominantly impaired in general emotion recognition compared to extra-MTLE patients. Performance in the epilepsy control group, although not significantly differing from performance in either the MTLE or the healthy control group, lay between these two groups. MTLE can be considered a significant risk factor for the development of deficits in social cognition beyond weaknesses that might be associated with epilepsy as a stigmatized chronic neurological disorder. The presence of deficits in social cognition may explain various behavioural symptoms that have historically driven concepts such as "epileptic personality" or "interictal personality disorder" and may indicate new routes for therapeutic interventions.     

Semantic memory in partial epilepsy: verbal and non-verbal deficits and neuroanatomical relationships

Semantic memory was evaluated in 124 epilepsy patients, including 84 with left (n=44) or right temporal lobe epilepsy (TLE) (n=40) and 40 with left (n=25) or right frontal lobe epilepsy (FLE) (n=15), in order to determine their verbal and visual deficits, and the neuroanatomical relationships between them. The controls were 35 healthy subjects. Semantic memory was assessed by means of Picture Naming, Picture Pointing, the verbal Pyramid and Palm Trees Test (PPTT), the visual PPTT, Object Decision Hard, and Drawing From Memory. Episodic memory was assessed by means of the Short Story, Rey's Complex Figure, the Verbal and Visual Selective Reminding Procedure and Brown-Peterson Procedure. Factor analysis of the epilepsy patients distinguished their semantic memory scores from other neuropsychological domains. The semantic memory factor was significantly related to the side of the epileptic region, with lower scores in the left hemisphere and left TLE patients. In comparison with the controls, the left TLE patients were significantly impaired on Picture Naming, Picture Pointing, and Object Decision Hard. Subsequent analyses showed that, in comparison with the controls and the right TLE patients, the left TLE patients with lateral temporal lobe lesions were impaired in Picture Naming whereas, in comparison with the controls, the left TLE patients with mesial temporal lobe lesions were impaired in Object Decision Hard. On the contrary, the episodic memory factor was not related to the side of the epileptic region, and a few material-specific tests revealed opposite impairments in the left and right hemisphere patients. These results show that left TLE may cause semantic memory deficits involving verbal and visual information. Unlike the material-specific pattern of episodic memory, this pattern of impairment is in line with the view of an amodal semantic store in which all of the information about a thing overlaps. The semantic memory impairment may reflect damage in the lateral and mesial temporal lobe regions that impair neocortical functions in storing and retrieving information or hippocampal functions in processing meaningful stimuli.