SEARCH · PubMed Health

Results for “TLE”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 91 records · Page 5Linked to original sources

PubMed2005

Lateralized anterior mesiotemporal lobe activation: semirandom functional MR imaging encoding paradigm in patients with temporal lobe epilepsy--initial experience.

PURPOSE: To prospectively demonstrate anterior mesiotemporal lobe (MTL) activation in healthy volunteers by using a semirandom memory-encoding paradigm and to prospectively compare lateralized functional magnetic resonance (MR) imaging activation with intracarotid amobarbital procedure (IAP) memory test results in patients with temporal lobe epilepsy (TLE) who were scheduled to undergo surgery. MATERIALS AND METHODS: The study was approved by a local ethics committee, and written informed consent was obtained from all subjects. Eight healthy volunteers and 18 patients with TLE who were scheduled for surgery were included in the functional MR imaging study involving the use of a memory-encoding paradigm with variable epoch lengths. Subjects were instructed to memorize new pictures that were mixed among pictures that they had seen before. Data analysis entailed computations of the contrast between the MTL activation induced by the new pictures and the MTL activation induced by the old pictures and of the lateralization index, defined as the relative difference in the number of activated voxels between the left and right MTLs. Lateralization indexes were compared between the patients and the volunteers and statistically correlated with the patients' IAP memory test results. To study deviations from perfect correspondence between the functional MR imaging- and IAP-derived lateralization indexes, orthogonal regression analysis was applied. Proportional relations for the patients with left-sided TLE and for those with right-sided TLE were calculated separately. RESULTS: The memory paradigm consistently activated the posterior and anterior MTL structures in both the healthy volunteers and the patients. Regression analysis revealed that functional MR imaging activation was stronger than the IAP results when it was lateralized to the contralateral MTL. This analysis also revealed a significant (P < .001) correlation between the functional MR imaging results and the IAP results in the patients with right-sided TLE but not in those with left-sided TLE (P > .1). CONCLUSION: The functional MR imaging memory-encoding paradigm consistently yielded MTL activation in the volunteers and the patients with TLE, but lateralized functional MR imaging activation was in concordance with the IAP results in only those patients with right-sided TLE.

Adult↗

PubMed2004

Temporal lobe volumes in patients with hippocampal sclerosis with or without cortical dysplasia.

BACKGROUND: Recent MRI-based volume reconstruction studies in intractable temporal lobe epilepsy (TLE) due to hippocampal sclerosis (HS) suggested atrophy that extends to the adjacent neocortical areas. OBJECTIVE: To study the extent of temporal lobe volume (TLV) abnormalities in patients with pathologically confirmed HS (with or without cortical dysplasia [CD]) who underwent anterior temporal lobectomy for the treatment of drug-resistant TLE. METHODS: Fifty patients (right TLE: n = 24; left TLE: n = 26) were found to have HS (hippocampal cell loss of >30%). Associated neocortical CD was seen in 20 patients (43%). MRI-based TLVs and hippocampal and hemispheric volume reconstructions in all patients were compared between pathologic groups and with volumes acquired from 10 age-matched control subjects. RESULTS: TLVs ipsilateral to the epileptogenic zone in patients with TLE were smaller than TLVs in control subjects (p < 0.01). In patients with left TLE, TLVs ipsilateral to the epileptogenic zone were smaller than contralateral TLVs (left: 66.6 +/- 8.3 cm3, right: 74.9 +/- 10.0 cm3; p < 0.001). In patients with right TLE, there were no significant asymmetries. The contralateral TLVs (regardless of the side of surgery) were smaller in the HS + CD group than the HS group (HS + CD group: 74.9 +/- 8.6 cm3, HS group: 79.7 +/- 6.6 cm3; p < 0.05). Patients with HS + CD had a tendency to have less hippocampal atrophy and slightly smaller TLVs ipsilateral to the epileptogenic zone, accounting for significantly smaller TLV/hippocampal volume ratios compared with patients with HS alone. CONCLUSIONS: Drug-resistant TLE due to HS is associated with extrahippocampal temporal lobe atrophy. The presence of bilateral temporal lobe atrophy is suggestive of a more widespread (bilateral) temporal lobe involvement in patients with HS and CD.

Adolescent↗

PubMed2006

New-onset temporal lobe epilepsy in children: lesion on MRI predicts poor seizure outcome.

OBJECTIVE: To determine factors predictive of long-term seizure outcome in children with new-onset temporal lobe epilepsy (TLE). METHODS: A community-based cohort of 77 children with new-onset TLE, including 14 with possible TLE, were followed prospectively with formal review 7 and 14 years following seizure onset. Diagnoses were re-evaluated at each review, and changed when new clinical, EEG, or imaging data were compelling. RESULTS: Sixty-four patients sustained the diagnosis of TLE over time; two were lost to follow-up. Age at follow-up was 12 to 29 years (median 20 years). Median follow-up was 13.7 years, 95% being followed for greater than 10 years. Nineteen patients were seizure free (SF) and off treatment, having not had seizures for 5 to 15 years. Duration of active TLE in the SF group was 1 to 8 years, the children being treated with 0 to 3 antiepileptic drugs (AEDs). Forty-three patients were not seizure free (NSF) and had ongoing seizures or had undergone epilepsy surgery. These children were treated with 1 to 10 AEDs. Fifteen NSF patients experienced 22 nonterminal seizure remissions of 1 to 7 years duration. Seventeen children had a significant antecedent to TLE. Lesions were identified on neuroimaging in 28 and included hippocampal sclerosis (HS) in 10, tumor in 8, and dysplasia in 7. All children with lesions on MRI were NSF (p < 0.001). Focal slowing on EEG was also associated with persistent seizures (p = 0.05), although this was correlated with a lesion on MRI. Infantile onset of epilepsy, family history of seizures, initial seizure frequency, antecedents, and early seizure remissions were not predictive of seizure outcome. CONCLUSION: Seizures spontaneously remit in approximately one third of children with new-onset TLE. A lesion on MRI predicts intractable seizures in TLE and the potential need for epilepsy surgery.

Adolescent↗

PubMed1994

Preoperative and postoperative glucose consumption in mesiobasal and lateral temporal lobe epilepsy.

We have studied 25 patients with interictal 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) before and after selective surgery for temporal lobe epilepsy (TLE). Based on the findings of the presurgical evaluation, including ictal intracranial EEGs, histopathologic findings, and the postoperative outcome, we classified the patients in three subgroups: (1) patients with TLE of lateral temporal origin (n = 5), (2) patients with mesiobasal limbic TLE associated with mesial gliosis (n = 14), and (3) patients with mesiobasal limbic TLE and small mesial tumors (n = 6). Postoperatively, patients with mesiobasal limbic TLE and mesial gliosis and five of six patients with mesiobasal limbic TLE and mesial tumors were seizure-free; the remaining sixth patient had one generalized seizure. Patients with TLE of lateral temporal origin had more than 90% reduction of seizure frequency. The main postoperative metabolic findings were as follows: (1) marked increase of regional cerebral metabolic rate of glucose (rCMRglu), both in the ipsilateral and, significantly, in the contralateral hemisphere in patients with mesiobasal limbic TLE and mesial gliosis-the changes of brain metabolism were characteristic for patients with the syndrome of "mesial temporal lobe epilepsy" (MTLE); (2) decrease of rCMRglu values in the contralateral mesiobasal temporal lobe (TL) cortex in all patient groups--the reduction of rCMRglu in homologous brain structures contralateral to the operated side provides evidence for stronger interhemispheric connections between both mesial TL structures than were hitherto supposed; and (3) a trend toward a normalization of rCMRglu values in the ipsilateral temporal neocortex 12 months after surgery in patients with MTLE syndrome.

Adolescent↗

PubMed2001

Response to first drug trial predicts outcome in childhood temporal lobe epilepsy.

OBJECTIVE: To construct a clinical prediction model for the early identification of children destined to develop refractory temporal lobe epilepsy (TLE) 2 years after epilepsy onset. METHODS: Patients with TLE between 1 and 18 years old seen in the Division of Neurology at Children's Hospital of Philadelphia during 1999 were identified through billing records and chart review. Data were abstracted independently on 5 candidate predictor variables for refractory TLE and on seizure frequency outcome at 2 years after epilepsy onset. RESULTS: One hundred twenty patients met inclusion criteria and had at least 2 years of follow-up. Forty-five of 120 patients (37.5%) had refractory TLE at 2 years after onset, and 75 of 120 (62.5%) were seizure free. Three significant predictors of refractory TLE were found on bivariate analysis: an early risk factor for epilepsy (risk ratio = 3.5 [95% CI 2.2, 5.6]), temporal lobe abnormality on MRI scan (2.9 [95% CI 1.9, 4.6]), and failure of the first antiepileptic drug (AED) trial (16.5 [95% CI 6.3, 43.9]). Logistic regression indicated that the best model to predict refractory TLE contained only the variable "failure of first AED trial," with a positive predictive value of 0.89 (95% CI 0.76, 0.96) and negative predictive value of 0.95 (95% CI 0.87, 0.99) to predict "refractory TLE" at 2 years. CONCLUSIONS: Failure of first AED trial accurately predicts refractory TLE at 2 years after onset, based on retrospective cohort data in children. If verified prospectively and with longer follow-up, this finding should support earlier consideration of surgical options.

Anticonvulsants↗

PubMed1990

[Effects of unilateral temporal lobectomy on verbal dichotic listening test].

Verbal dichotic listening test was conducted before and after anterior temporal lobectomy on 25 patients who underwent the operation because of their medication-resistant epileptic seizures. Their speech dominance by Wada test was all left sided. 1. Preoperatively, patients having the epileptogenic focus in the right temporal lobe (R-TLE) and those having the focus in the left (L-TLE) were, as expected, all right-ear dominant. The mean number of correct responses was fewer in L-TLE than in R-TLE group. 2. Postoperatively, no detrimental effects for recognition of verbal auditory stimuli by the ear contralateral to the focus was observed both in L-TLE and in R-TLE group. 3. Postoperatively, the ear-dominance shifted: to the left in patients with L-TLE, and to the right more conspicuously in patients with R-TLE compared to the preoperative scores. In other words, the recognition ability by the ears ipsilateral to the side of focus, or of resected temporal lobe, was ameliorated. Summarizing, the unilateral anterior temporal lobectomy did not cause "lesion effect" but yielded improvement of verbal auditory recognition by ears ipsilateral to the epileptogenic focus. Diminished epileptic bombardment resulted in by the resection surgery may be a possible explanation.

Adult↗

PubMed1993

Interictal metabolic anatomy of mesial temporal lobe epilepsy.

OBJECTIVE--To examine patterns of temporal and extratemporal regional interictal glucose hypometabolism in individual patients with unilateral mesial temporal lobe epilepsy (TLE). Previous reports disagree on which extratemporal areas can be hypometabolic in TLE. DESIGN--Case series of patients with TLE who underwent interictal fludeoxyglucose F 18 positron emission tomography, compared quantitatively with normal positron emission tomography. SETTING--Patients referred for surgical treatment of medically refractory complex partial seizures. PATIENTS AND OTHER PARTICIPANTS--Ten normal volunteers; 27 patients with TLE selected to exclude seizures of bilateral temporal or extratemporal onset. RESULTS--Regional hypometabolism occurred in 25 patients. Hypometabolic regions were ipsilateral to seizure onset and included lateral temporal (in 78% of patients), mesial temporal (70%), thalamic (63%), basal ganglial (41%), frontal (30%), parietal (26%), and occipital (4%). Specific patterns of temporal and extratemporal hypometabolism varied considerably across the TLE group. CONCLUSIONS--Any of the previously reported anatomic areas of hypometabolism can occur in individual patients with TLE. The prevalence of thalamic hypometabolism suggests a pathophysiologic role for the thalamus in initiation or propagation of temporal lobe seizures or in the interictal cognitive dysfunction of TLE.

Adult↗

PubMed1998

Remodeling of neuronal circuitries in human temporal lobe epilepsy: increased expression of highly polysialylated neural cell adhesion molecule in the hippocampus and the entorhinal cortex.

Neuronal loss and axonal sprouting are the most typical histopathological findings in the hippocampus of patients with drug-refractory temporal lobe epilepsy (TLE). It is under dispute, however, whether remodeling of neuronal circuits is a continuous process or whether it occurs only during epileptogenesis. Also, little is known about the plasticity outside of the hippocampus. We investigated the immunoreactivity of the highly polysialylated neural cell adhesion molecule (PSA-NCAM) in the surgically removed hippocampus and the entorhinal cortex of patients with drug-refractory TLE (n=25) and autopsy controls (n=7). Previous studies have shown that the expression of PSA-NCAM is associated with the induction of synaptic plasticity, neurite outgrowth, neuronal migration, and events requiring remodeling or repair of tissue. In patients with TLE, the optical density (OD) of punctate PSA-NCAM immunoreactivity was increased both in the inner and outer molecular layers of the dentate gyrus, compared with controls. The intensity of PSA-NCAM immunoreactivity in the inner molecular layer correlated with the duration of epilepsy, severity of hippocampal neuronal loss, density of mossy fiber sprouting, and astrogliosis. In TLE patients with only mild neuronal loss in the hippocampus, the density of infragranular immunopositive neurons was increased twofold compared with controls, whereas in TLE patients with severe neuronal loss, the infragranular PSA-NCAM-positive cells were not present. In the hilus, the somata and tortuous dendrites of some surviving neurons were intensely stained in TLE. PSA-NCAM immunoreactivity was also increased in CA1 and in layer II of the rostral entorhinal cortex, where immunopositive neurons were surrounded by PSA-NCAM-positive fibers and puncta. Our data provide evidence that synaptic reorganization is an active process in human drug-refractory TLE. Moreover, remodeling is not limited to the dentate gyrus, but also occurs in the CA1 subfield and the entorhinal cortex.

Adult↗

PubMed2005

Duplicated members of the Groucho/Tle gene family in fish.

The highly conserved Groucho/Tle gene family has widespread functions during embryonic development and in adults. For mammalians, four full-length Tle paralogues are known, whereas the whole spectrum of this gene family in fish species has not been analysed yet. Most detailed data exist for medaka, where 3 Tle genes have been described, Tle1, Tle3, and Tle4. We now isolated 3 additional Tle genes from the medaka genome. Sequence analysis identifies these genes as Tle2a, Tle2b, and Tle3b. Database searches of genomic sequences revealed an identical set of Tle paralogues being present in distantly related fish species, indicating duplicated Tle2 and Tle3 genes for the complete teleost lineage. Like the previously analysed medaka Tle genes, the three new genes show a broad expression pattern during embryogenesis. Nevertheless, a detailed comparison of all six Tle genes reveals critical differences in certain aspects of their expression pattern. In particular, we concentrated on the activity of Tle genes during ear development and found Tle2a and Tle2b expressed in this sensory organ.

Amino Acid Sequence↗

PubMed1999

Voxel-by-voxel comparison of automatically segmented cerebral gray matter--A rater-independent comparison of structural MRI in patients with epilepsy.

Quantitative evaluation of MRI in patients with epilepsy can give more information than qualitative assessment. Previously developed volume-of-interest-based methods identified subtle widespread structural changes in the neocortex beyond the visualized lesions in patients with malformations of cortical development (MCD) and hippocampal sclerosis (HS) and also in MRI-negative patients with juvenile myoclonic epilepsy (JME). This study evaluates a voxel-based automated analysis of structural MRI in epilepsy. After fully automated segmentation of cerebral gray matter from structural T1-weighted, high-resolution MRI scans, we applied the automated and objective technique of statistical parametric mapping (SPM) to the analysis of gray matter of 35 control subjects, 10 patients with partial seizures and MCD, 10 patients with left temporal lobe epilepsy (TLE) and HS, 10 patients with left TLE and normal MR quantitation of the hippocampus, and 20 patients with JME. At a corrected threshold of P < 0.05, significant abnormalities were found in 3/35 controls; in all 10 patients with MCD, 6 of whom had additional lesions beyond the margins of the visualized abnormalities; in 2/10 TLE patients with HS; in 2/10 MRI-negative TLE; and in 4/20 JME patients. Group comparisons between control subjects and HS patients identified the affected left temporal lobe with an increase in gray matter in the posterior temporal lobe, but did not identify hippocampal atrophy. The group of MRI-negative TLE patients showed no abnormalities compared with control subjects. Group comparison between control subjects and JME patients identified a mesial frontal increase in gray matter. The SPM-based voxel-by-voxel comparison of gray matter distribution identified MCD and abnormalities beyond the visualized lesion in individual MCD patients. The method did not reliably identify HS in individual patients or identify abnormalities in individual MRI-negative patients with TLE or JME in a proportion larger than the chance findings in the control group. Using group comparisons, structural abnormalities in the neocortical gray matter of patients with TLE and HS were lateralized to the affected temporal lobe. In patients with JME as a group, an increase in gray matter was localized to the mesial frontal area, corroborating earlier quantitative MRI findings.

Adolescent↗

PubMed2004

Febrile seizures and mechanisms of epileptogenesis: insights from an animal model.

Temporal lobe epilepsy (TLE) is the most prevalent type of human epilepsy, yet the causes for its development, and the processes involved, are not known. Most individuals with TLE do not have a family history, suggesting that this limbic epilepsy is a consequence of acquired rather than genetic causes. Among suspected etiologies, febrile seizures have frequently been cited. This is due to the fact that retrospective analyses of adults with TLE have demonstrated a high prevalence (20-->60%) of a history of prolonged febrile seizures during early childhood, suggesting an etiological role for these seizures in the development of TLE. Specifically, neuronal damage induced by febrile seizures has been suggested as a mechanism for the development of mesial temporal sclerosis, the pathological hallmark of TLE. However, the statistical correlation between febrile seizures and TLE does not necessarily indicate a causal relationship. For example, preexisting (genetic or acquired) 'causes' that result independently in febrile seizures and in TLE would also result in tight statistical correlation. For obvious reasons, complex febrile seizures cannot be induced in the human, and studies of their mechanisms and of their consequences on brain molecules and circuits are severely limited. Therefore, an animal model was designed to study these seizures. The model reproduces the fundamental key elements of the human condition: the age specificity, the physiological temperatures seen in fevers of children, the length of the seizures and their lack of immediate morbidity. Neuroanatomical, molecular and functional methods have been used in this model to determine the consequences of prolonged febrile seizures on the survival and integrity of neurons, and on hyperexcitability in the hippocampal-limbic network. Experimental prolonged febrile seizures did not lead to death of any of the seizure-vulnerable populations in hippocampus, and the rate of neurogenesis was also unchanged. Neuronal function was altered sufficiently to promote synaptic reorganization of granule cells, and transient and long-term alterations in the expression of specific genes were observed. The contribution of these consequences of febrile seizures to the epileptogenic process is discussed.

Animals↗

PubMed2005

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.

Adult↗

PubMed2004

Day/night patterns of focal seizures.

PURPOSE: In many patients with epilepsy seizures occur with a day/night pattern. Our aims were to compare day/night patterns in seizure frequency among patients with different epileptogenic regions. METHODS: We analyzed video-EEG recordings in 15 patients with temporal lobe (TLE) and 11 with extratemporal lobe epilepsy (XTLE). Each seizure was classified according to subject group (TLE vs XTLE), sleep/wake state, and time of day of seizure occurrence (grouped into 6 x 4-hour "bins"). RESULTS: Of 90 seizures, 41 occurred in TLE and 49 in XTLE patients. There were day/night patterns of seizure occurrence in each group, with differences in the patterns between groups. In TLE, 50% of seizures occurred between the hours of 15:00 and 19:00 (17% would be expected by chance in each 4-hour "bin": F=3.59, P<0.006). In XTLE, there was a peak between 19:00 and 23:00 (47%: F=4.72, P<0.0018). The effect of time on seizures was least pronounced in the XTLE patients who had more than one epileptogenic region. The proportion of seizures occurring from sleep was significantly less in TLE (19%) than in XTLE patients (41%) [P<0.04, Fisher's exact test]. CONCLUSIONS: There are clear day/night patterns of seizure occurrence in epilepsy, with differences in the patterns between TLE and XTLE. There is an additional interaction with sleep/wake state, with relatively few seizures occurring from sleep in TLE compared with XTLE. Thus, it appears that both sleep/wake state and day/night or circadian rhythms may affect seizure proclivity, with different effects depending on the location of the epileptogenic region.

Adult↗

PubMed2005

Response inhibition and set shifting in patients with frontal lobe epilepsy or temporal lobe epilepsy.

Patients with frontal lobe epilepsy (FLE), patients with temporal lobe epilepsy (TLE), and matched controls were administered a test of response inhibition and set shifting (switching) (Color Word Interference Test, CWIT). Patients with FLE were impaired relative to the controls across all conditions of the CWIT, with the FLE patients showing disproportionate impairment in the Inhibition and Inhibition/Switching conditions. In contrast, the TLE patients did not differ from controls. Further analysis of the patient groups revealed that patients with left FLE were impaired relative to those with right FLE, left TLE, and right TLE in the Inhibition condition. In the Inhibition/Switching condition, patients with left FLE and left TLE were impaired relative to their right-sided counterparts. Finally, performance by the TLE group in the Inhibition/Switching condition was correlated with seizure frequency. These data suggest that patients with FLE, but not TLE, show impaired inhibition and set shifting relative to controls. In addition, side of the seizure focus and seizure frequency may contribute to executive dysfunction in patients with epilepsy.

Adult↗

PubMed2005

Obsessionality, obsessive-compulsive disorder, and temporal lobe epilepsy.

We evaluated the prevalence of obsessive-compulsive disorder (OCD) in patients with temporal lobe epilepsy (TLE) and we investigated the hypothesis that obsessionality may represent a trait in TLE. Eighty-two consecutive patients with epilepsy, 62 with TLE and 20 with idiopathic generalized epilepsy (IGE), and 82 matched healthy controls were evaluated using the SCID-IP, Y-BOCS, MMPI-2 (specifically the Psychasthenia and Obsessiveness scales), BDI, and STAI Y1 and Y2. Nine of the TLE patients, none of the IGE patients, and one of the controls had a diagnosis of OCD. Psychasthenia and Obsessiveness scores were significantly higher in the TLE than in the IGE and control groups. Patients with TLE and OCD differed significantly with respect to history of depression when compared with patients with TLE without OCD, whereas there were no differences in age at onset and duration of epilepsy, seizure pattern and frequency, MRI features, laterality of the EEG focus, antiepileptic drug therapy and combinations, and BDI scores.

Adolescent↗

PubMed2026

Altered EEG microstate dynamics reflect depressive symptoms in temporal lobe epilepsy.

BACKGROUND: Depressive symptoms are a common and disabling comorbidity in temporal lobe epilepsy (TLE), yet the neural mechanisms linking seizure networks to affective symptoms remain unclear. Although limbic network dysfunction has been implicated in both epilepsy and depressive disorders, it is unknown whether the time-varying dynamics of large-scale electrophysiological brain states reflect depressive symptom severity in TLE. In this study, we examined whether EEG microstate dynamics capture network alterations associated with depressive symptoms in individuals with unilateral TLE. METHODS: We analyzed resting-state, visually normal scalp EEG from 26 individuals with unilateral TLE. EEG microstates were identified by clustering global field power peaks into four canonical classes, with electrode positions mirrored to align the ictal hemisphere across subjects. Microstate dwell time, fractional occupancy, global transition entropy, and Markov transition probabilities were quantified and related to Beck Depression Inventory-II (BDI) scores. RESULTS: Individuals with high depressive symptoms (BDI ≥ 13; N = 12) exhibited longer mean dwell time in the ictal hemisphere-aligned microstate compared with individuals with low depressive symptom burden (BDI < 13; N = 14). Across subjects, dwell time in this microstate correlated with depressive symptom severity (r = 0.57, p = 0.002). TLE individuals with higher depressive symptoms exhibited reduced global transition entropy (p = 0.02), which also correlated with depressive symptom severity (r = -0.54, p = 0.004), indicating decreased flexibility of microstate transitions. Despite similar fractional occupancy of this state between groups, individuals with higher depressive symptoms were less likely to transition into the ictal hemisphere-aligned microstate from non-ictal or posterior configurations. Once engaged, however, the ictal-aligned microstate showed increased persistence, indicating prolonged stabilization of this network configuration. CONCLUSION: Higher depressive symptom burden in unilateral TLE is associated with increased temporal rigidity of the ictal hemisphere-aligned brain microstate, reflecting impaired disengagement of epileptogenic network configurations. These findings suggest that depressive symptoms in TLE may be associated with epilepsy-related disruptions in large-scale neural dynamics.

Humans↗

PubMed1997

Sexual behavior and hemispheric laterality of the focus in patients with temporal lobe epilepsy.

Various studies have described an unusually common incidence of sexual and reproductive dysfunction in patients affected by temporal lobe epilepsy (TLE). The purpose of the present study was to further investigate, by means of an ad hoc questionnaire, the relationship between sexual disorders and the hemispheric laterality of the epileptic focus in men and women with right (R) TLE and left (L) TLE. The results suggest a reduction of sexual interest in patients with R-TLE as compared with L-TLE in both men and women. This effect was fundamentally observed when sexual interest was implicitly explored. No significant difference was found between R-TLE and L-TLE groups concerning most aspects of sexual performance. Various hypotheses are discussed to interpret this effect of hemispheric lateralization on sexual interest.

Adult↗

PubMed2001

Relation of sorting impairment to hippocampal damage in temporal lobe epilepsy.

One hundred and twelve patients with left (n=65) or right (n=47) temporal lobe epilepsy (TLE), associated with mesial or lateral temporal lobe lesion, were compared to 53 patients with left (n=30) or right (n=23) frontal lobe epilepsy (FLE), in order to explore the contributions of hippocampal lesions and of memory deficits to sorting impairment. Thirty-six healthy subjects of similar age and education were controls. The Modified Wisconsin Card Sorting Test (MWCST) was used to explore sorting ability. The two-syllable word span and consistent long-term retrieval from the selective reminding procedure for word-list learning were used to evaluate memory. Raven's Coloured Progressive Matrices and Attentive Matrices served to control for abstract reasoning and attention. Left FLE patients and TLE patients with left hippocampal sclerosis were significantly impaired on MWCST, short-term memory, and word learning. TLE patients with other left hippocampal lesions were also impaired on MWCST, although not significantly so. Analysis of individual scores showed that 42% of TLE patients with left hippocampal sclerosis, 14% of TLE patients with other hippocampal lesions, 63% of left FLE patients, and 30% of right FLE patients were impaired on the MWCST. In patients with left hippocampal sclerosis, MWCST score was associated with the learning score provided by the selective reminding procedure and Raven's Coloured Progressive Matrices score, whereas in FLE patients, MWCST score was associated with Attentive Matrices score. These results suggest that only some TLE patients, i.e. those with hippocampal damage, may be expected to be impaired on card sorting. The impaired sorting ability of these TLE patients may be due to involvement of the hippocampal function in forming associations or in registering new information.

Adult↗