Extratemporal Lobe Research Articles

Risk factors for complications during intracranial electrode recording in presurgical evaluation of drug resistant partial epilepsy

Intracranial electrode monitoring is still required in epilepsy surgery; however, it is associated with significant morbidity. To identify risk factors associated with complications during invasive intracranial EEG monitoring. Retrospective study of all patients undergoing invasive monitoring at Westmead between 1988-2004. From detailed chart reviews, the following variables were recorded: duration of intracranial monitoring, the site of grid implantation, number of grids and electrodes, seizure frequency, postoperative complications and seizure outcome. Seventy-one patients (median age: 24 years) underwent subdural electrode implantation; 62% had extratemporal lobe epilepsy and 46% were non-lesional. Of the 58 monitored patients who had cortical resections, 45 had good seizure outcomes. Complications related to subdural electrode implantation included transient complications requiring no treatment (12.7%), transient complications requiring treatment (9.9%) and two deaths (2.8%). Specific complications included subdural haemorrhage, transient neurological deficit, infarction and osteomyelitis. The two deaths occurred within 48 h of implantation were related to raised intracranial pressure (one venous infarction, one unexplained). Complications were associated with maximal size of grid (p < 0.001), greater number of electrodes (p < 0.001), electrode density per cortical surface implanted (p < 0.001), right central surface implantation (p = 0.003) and left central surface implantation (p = 0.013). Multiple logistic regression identified larger size grids and right central surface implantation as independent predictors of complications. There are significant complications during intracranial EEG evaluations but the majority of these are transient. We found a relationship between the size of the electrode arrays and the incidence of complications. The results of this study have been used to modify our implantation and monitoring protocols.

The impact of lesions and epilepsy on personality and mood in patients with symptomatic epilepsy: A pre- to postoperative follow-up study

To discern more static and lesion based from more dynamic epilepsy-driven features of depression and personality in focal symptomatic epilepsy, change in personality and mood was examined as a function of focus lateralization and seizure outcome after epilepsy surgery. Self-reported personality and depression were assessed before and 1 year after epilepsy surgery in 151 consecutive patients with temporal (N=125) or extratemporal lobe epilepsy (N=26). At baseline only depressed mood (31%) and introversion (38%) appeared elevated, the first being more frequent in right lateralized epilepsies, the latter being pronounced in temporal lobe epilepsy. After surgery, seizure freedom was associated with a significant change in neuroticism as well as with improvements in mood and symptoms of an organic psycho-syndrome. Differential changes were observed for seizure-free left (enhanced emotional stabilization) versus right temporal resected patients (decreased anxiety and impulsivity, less vegetative symptoms). Apart from elevated depression and introversion scores which showed some relation to pathology, no major deviant personality features could be discerned. While seizure freedom related improvements may indicate both epilepsy and reactively driven behavioral changes, the differential recovery observed in seizure-free left versus right temporal resected patients indicate epilepsy-specific behavioral dysfunction.

Elevated serum neuron-specific enolase in patients with temporal lobe epilepsy: A video–EEG study

Established markers of brain damage, neuron-specific enolase (NSE) and S-100b protein (S-100), may increase after status epilepticus, but whether a single tonic-clonic or complex partial seizure induces elevation of these markers is not known. Furthermore, it is unclear whether the risk of seizure-related neuronal damage in temporal lobe epilepsy (TLE) differs from that in extratemporal lobe epilepsies (XTLE). The aim of this study was to analyze NSE and S-100 in patients with TLE and XTLE after acute seizures. The levels of NSE and S-100 were measured in serum before (0h) and at 3, 6, 12, and 24h after acute seizures in 31 patients during inpatient video-EEG monitoring. The patients were categorized into the TLE and the XTLE group based on video-EEG recordings and MRI findings. Fifteen patients had TLE and 16 XTLE. Index seizures were mainly complex partial seizures (n=21). In TLE mean+/-S.D. values for NSE levels (mug/L) were 8.36+/-2.64 (0h), 11.35+/-3.84 (3h), 13.48+/-4.49 (6h), 12.95+/-5.46 (12h) and 10.33+/-3.13 (24h) (p=0.006, ANOVA). In XTLE the changes were not significant (p=0.3). There was less increase in the levels of S-100 in TLE (p=0.05) and no significant change in XTLE (p=0.4). The levels of markers of neuronal damage were increased in patients with TLE, not only after tonic-clonic but also after complex partial seizures. These data suggest that TLE may be associated with brain damage.

STRUCTURAL ABNORMALITIES OF THE ADHESIO INTERTHALAMICA AND MEDIODORSAL NUCLEI OF THE THALAMUS IN SCHIZOPHRENIA

Structural and functional abnormalities in the thalamocortical network in primary generalized epilepsies or mesial temporal lobe epilepsy have recently been identified by voxel-wise analyses of neuroimaging. However, evidence is needed regarding the profiles of the thalamocortical network in patients with secondarily generalized seizures from focal neocortical sources. We used high-resolution T1-weighted, diffusion-tensor and resting-state functional MR imaging (rs-fMRI) to examine 16 patients with secondarily generalized extratemporal lobe seizures and 16 healthy controls. All the patients were medically effective and MRI-negative. Using whole brain voxel-based morphometry (VBM) to compare the patients with the normal controls, we observed significantly decreased gray matter (GM) density in the thalamus and 3 frontal gyri and significantly reduced white matter (WM) fractional anisotropy (FA) in the bilateral anterior corona radiata of the patients. Alterations in the thalamocortical functional connectivity with different cortices were identified by the rs-fMRI analysis seeding of the whole thalamus. The prefrontal gyri with the greatest functional connectivity were also traced by seeding a sub-thalamic region that is demarcated in an atlas, in which the thalamic parcellation is based on the WM connectivity to the cortices. This sub-thalamic region anatomically contains the mediodorsal thalamic nucleus where, concordantly, there was a significant decrease in thalamic GM density in the VBM study. In contrast to the negative correlation between the disease duration and reduced thalamic densities and subcortical FA values, the strength of the functional thalamocortical connectivity had a paradoxical correlation. Our results conclusively indicate that generalized seizures with a focal cortical source are associated with structural and functional alterations in the thalamocortical network.

Factors contributing to resectability and seizure outcomes in 44 patients with ganglioglioma

Objectives The purpose of this retrospective study was to evaluate causes contributing to surgical resectability and seizure outcomes depending on various clinical and surgical factors. Patients and methods The records of 44 patients with gangliogliomas surgically treated between April 1986 and March 2007, were retrospectively reviewed to assess presenting symptoms, resectability and seizure outcomes. Results Tumors were located in the supratentorial areas in 33 cases, the infratentorial area in 9 cases and the spinal cord in 2 cases. Thirty-five cases underwent gross total removal and 9 cases underwent subtotal resection. Only 2 cases underwent postoperative radiotherapy and 2 cases underwent gamma knife surgery. Twenty-six patients presented seizure symptoms of which 22 cases were located in temporal lobe and 4 cases were located in the extratemporal lobe. Twenty-three patients (88.5%) were seizure-free after surgery. Two patients were Engel class II and another was Engel class III. Conclusion We concluded that tumor location and seizure-presenting symptoms are good predictors of gross total removal. Gross total removal of ganglioglioma had a better chance of leaving the patient seizure free after surgery rather incomplete resection. Our data do not support the concept that surgical methods, invasive monitoring and surrounding cortical malformation correlated with seizure-free outcome.

Diffusion tensor analysis of temporal and extra-temporal lobe tracts in temporal lobe epilepsy

To determine whether the major temporal lobe white matter tracts in patients with temporal lobe epilepsy manifest abnormal water diffusion properties. Diffusion tensor MRI measurements were obtained from tractography for uncinate, arcuate, inferior longitudinal fasciculi and corticospinal tract in 13 children with left temporal lobe epilepsy and normal conventional MRI, and the data were compared to measurements in 12 age-matched normal volunteers. The relationship between tensor parameters and duration of epilepsy was also determined. All four tracts in the affected left hemisphere showed lower mean anisotropy, planar and linear indices, but higher spherical index in patients versus controls. Diffusion changes in the left uncinate and arcuate fasciculus correlated significantly with duration of epilepsy. Arcuate fasciculus showed a reversal of the normal left-right asymmetry. Various diffusion abnormalities were also seen in the four tracts studied in the right hemisphere. Our findings indicate abnormal water diffusion in temporal lobe and extra-temporal lobe tracts with robust changes in the direction perpendicular to the axons. Diffusion abnormalities associated with duration of epilepsy suggest progressive changes in ipsilateral uncinate and arcuate fasciculus due to chronic seizure activity. Finally, our results in arcuate fasciculus are consistent with language reorganization to the contralateral right hemisphere.

Tomographie par émission de positons (TEP) : quelles indications, quels bénéfices ?

Positron emission tomography (PET) is currently used in the presurgical workup for drug-resistant partial epilepsies in addition to MRI. Interictal metabolism is studied in clinical practice using (18)fluoro-desoxy-glucose ((18)FDG). In medial temporal lobe epilepsy (MTLE) associated with hippocampal sclerosis, hypometabolism ipsilateral to the epileptogenic focus is found in 70-90% of cases. However, hypometabolism is larger than the structural lesion observed on MRI and includes the epileptogenic zone and ictal discharge spread areas. Hypometabolism is related to surgical outcome and cognitive disturbances in MTLE. Although the usefulness of PET appears less well-established in extratemporal lobe epilepsy and in children, its sensitivity may be improved by coregistration and superimposition of PET on MRI at any age. Focal hypometabolism can be easily detected by visual analysis, allowing detection of minor gyral abnormalities that may correspond to focal cortical dysplasias. Moreover, in cases of negative MRI, focal hypometabolism findings may help invasive monitoring planning and deep electrode placement for SEEG, and finally improve surgical outcome.

Nonlesional Extratemporal Lobe Epilepsy in Children: Postsurgical Neurocognitive and Seizure Outcomes

Introduction Nonlesional extratemporal seizures present difficult treatment decisions in resective epilepsy surgery. Reported seizure outcomes vary and neurologic consequences of resection are manifold. Cognitive outcomes data on this population has been limited especially in children. This study attempts to expand our understanding of cognitive and seizure outcomes in children undergoing nonlesional extratemporal resections. Methods Twenty-five children with nonlesional extratemporal lobe seizure onset and comprehensive pre- and postoperative neuropsychological assessment underwent surgery at St. Louis Children's Hospital from 1994 to 2006 (13 frontal, 2 parietal, 2 occipital, 8 multiple). Repeated measures ANOVA were completed for each variable and two-factor analyses of variance for IQ and hemispheric onset. Seizure outcomes and morbidity were analyzed retrospectively. Results Mean age at surgery was 12 years (12 male, 13 female). Mean follow-up was 42.9 months. Clinically significant changes in overal...

Face processing in adolescents with and without epilepsy

Children with temporal lobe epilepsy frequently suffer memory deficits, often marked in face processing. To determine the neural correlates of this dysfunction, we investigated face processing in adolescents with intractable epilepsy compared to typically developing controls. The M170 and M220 MEG event-related fields (ERFs) were recorded while the adolescents completed an n-back task on blocks of upright and inverted faces. Source analyses of the ERF data were performed using an event-related beamforming technique that allowed the detection of multiple sources. The control adolescents showed the expected waveforms and inversion effects, although there were differences in source localization, compared to the adult literature. The participants with epilepsy had poor performance on the tasks. The adolescents with extra-temporal lobe epilepsy showed both the M170 and M220 but the source localizations were highly atypical. The patients with right temporal lobe epilepsy had an absent or highly atypical M220, a component related to face recognition processes. We hypothesize that the children with extra-temporal lobe epilepsy have difficulty with face encoding processes while the patients with right temporal lobe epilepsy have specific difficulty with face recognition.

Voxel‐based morphometry of temporal lobe epilepsy: An introduction and review of the literature

We review the applications and results of voxel-based morphometry (VBM) studies that have reported brain changes associated with temporal lobe epilepsy (TLE). A PubMed search yielded 18 applications of VBM to study brain abnormalities in patients with TLE up to May 2007. Across studies, 26 brain regions were found to be significantly reduced in volume relative to healthy controls. There was a strong asymmetrical distribution of temporal lobe abnormalities preferentially observed ipsilateral to the seizure focus, particularly of the hippocampus (82.35% of all studies), parahippocampal gyrus (47.06%), and entorhinal (23.52%) cortex. The contralateral hippocampus was reported as abnormal in 17.65% of studies. There was a much more bilateral distribution of extratemporal lobe atrophy, preferentially affecting the thalamus (ipsilateral = 61.11%, contralateral = 50%) and parietal lobe (ipsilateral = 47.06%, contralateral = 52.94%). VBM generally reveals a distribution of brain abnormalities in patients with TLE consistent with the region-of-interest neuroimaging and postmortem literature. It is unlikely that VBM has any clinical utility given the lack of robustness for individual comparisons. However, VBM may help elucidate some unresolved important research questions such as how recurrent temporal lobe seizures affect hippocampal and extrahippocampal morphology using serial imaging acquisitions.

Duration of complex partial seizures: An intracranial EEG study

The dynamics of partial seizures originating from neocortical and mesial temporal regions are thought to differ, yet there are no quantitative comparative studies. The studies reported here investigate the duration of complex partial seizures in these populations using analyses of seizures recorded from intracranial arrays. Data were collected from patients undergoing presurgical evaluation with intracranial electrodes. Seizure duration was defined as the time of earliest sustained ictal activity until the termination either in all electrodes (global duration, GD), or at the onset area (focal duration, FD). Patients were divided into three groups: mesial temporal lobe epilepsy (MTLE), neocortical temporal lobe epilepsy (NCTLE), and neocortical extratemporal lobe epilepsy (NCXTLE). Complex partial seizure durations were significantly longer in the MTLE group compared to the NCXTLE group. Median GD for MTLE was 106 s, and for NCXTLE was 78 s. There were no significant differences between seizure durations when comparing MTLE group to NCTLE group, or comparing NCTLE group to NCXTLE group. In the MTLE group, patients with bilateral recording arrays had significantly longer median seizure durations (GD and FD) than those sampled with unilateral arrays. In this select group of patients there is a significant difference between the duration of complex partial seizures of mesial temporal and neocortical extratemporal origin with mesial temporal complex partial seizures being longer. This may result from a number of possibilities including the bilateral propagation of some mesial temporal seizures and differences in ictal generators of the underlying networks.

Discontinuation of Antiepileptic Drugs after Pediatric Epilepsy Surgery

In children with medically intractable seizures, epilepsy surgery is now a widely accepted option. Successful discontinuation of antiepileptic drugs after epilepsy surgery has been reported in adults, but rarely in children. Surgical outcome and need for antiepileptic drugs after temporal and extratemporal lobe resection were retrospectively reviewed for 80 pediatric patients from the Comprehensive Epilepsy Program at the University of Alberta. For 1 year after surgery, children were maintained on at least one antiepileptic drug. Antiepileptic drug discontinuation was attempted in all patients with a nonepileptic electroencephalogram after 1 year seizure-free. Less than half of the patients (44%) eventually relapsed without antiepileptic drugs. Of the 40 patients in the temporal lobe group, 13 (32%) relapsed without antiepileptic drugs, as did 22 of the 40 extratemporal lobe resection patients (55%). Success rates for antiepileptic drug discontinuation after surgery were higher in the temporal lobe than in the extratemporal lobe group. Long-term antiepileptic drugs are not necessary in all cases, and for many children medication can be withdrawn after epilepsy surgery.

Efficacy of low-dose, add-on therapy of clobazam (CLB) is produced by its major metabolite, N-desmethyl-CLB

We evaluated the efficacy of low-dose, add-on therapy of CLB in adults with refractory epilepsy. 28 patients were included: 12 with temporal lobe epilepsy (TLE), 14 with extratemporal lobe epilepsy (ETLE) and 2 with symptomatic generalized epilepsy (SGE). CLB was added with the initial dose of 2.5 mg/day and increased to the optimal dose (mean, 5.6 mg/day). The mean observation period was 7.9 months. As compared with the baseline period, 14 out of 28 patients (50%) obtained an obviously good seizure control: 6 seizure free and 8 more than 50% of seizure reduction. The 14 patients comprised of 4 TLE, 8 ETLE and 2 SGE. In seizure type analysis, 26% of complex partial seizures (CPS), 64% of simple partial seizures (SPS) and 86% of generalized tonic-clonic seizures (GTC) showed a good control. Blood level of N-desmethyl-CLB in the steady state was higher in seizure-free group of 6 patients, and N-desmethyl-CLB blood level/dose per kg body weight correlated significantly to seizure control (p=0.0167). Our data show that even in low dose CLB was effective to patients with refractory epilepsy who had higher blood level of N-desmethyl-CLB.

Multimodality imaging for focus localization in pediatric pharmacoresistant epilepsy

Multiple structural and functional imaging modalities are available to localize the epileptogenic focus. In pre-surgical evaluation of children with pharmacoresistant epilepsy, investigations with the maximum yield should be considered in order to reduce the complexity of the workup. To determine the extent to which PET, ictal/interictal SPECT and its co-registration with the patient's MRI contributes to correct localization of the epileptogenic focus, surgical intervention and to the post surgical outcome in paediatric patients. The study population included children and adolescents with pharmacoresistant epilepsy (n = 50) who underwent preoperative evaluation, surgery and had postoperative follow-up for at least 12 months. Outcome was measured by postoperative seizure frequency using Engel's classification. Thirty-nine patients (78%) became completely seizure free after surgical intervention. The likelihood to benefit from surgical treatment was significantly higher if localization with more imaging modalities (MRI, PET, SPECT) were concordant with respect to the resected brain area (p < 0.01). Preoperative PET examination provided better localizing information in patients with extratemporal epilepsy and/or dysplastic lesions, whereas SPECT was found to be superior to PET in patients with temporal lobe epilepsy and/or tumors (p < 0.05). No significant difference was noted in the surgical outcome in younger or older age group, in children with or without special education needs. In paediatric epilepsy pre-surgical evaluation, the combined use of multiple functional imaging modalities for a precise localisation of the epileptogenic focus is worthwhile for both extratemporal and temporal lobe epilepsy, also when EEG and MRI alone are non-contributive, given the potential benefit of complete postoperative seizure control.

Localizing and Lateralizing Value of Behavioral Change in Childhood Partial Seizures

To describe clinical characteristics as well as localizing and lateralizing value of behavioral change (BC) at the onset of childhood seizures. Five hundred forty-one videotaped seizures of 109 consecutive patients < or = 12 years with partial epilepsy and postoperatively seizure-free outcome were analyzed. Behavioral change (the first clinical feature of a certain seizure with a sudden change in the child's behavior) was evaluated by two independent investigators. Thirty-three (30%) patients showed BC at least once during their seizures. Behavioral changes appeared in arrestive form in 19 and with affective activities in 18 children; four patients produced both kinds of BCs, separately. Arrest-type BC happened in 16 of 50 children with right- and 3 of 59 patients with left-sided seizure onset zone (p < 0.001). Affective-type BC was observed in 17 of 67 temporal lobe epilepsy patients while it happened in only 1 of 42 children with extratemporal lobe epilepsy (p = 0.001). Arrest-type BC lateralizes to the right hemisphere, while affective-type BC localizes to the temporal lobe in childhood partial seizures. Type of BCs can add important information to the presurgical evaluation of young children with refractory partial epilepsy.

Cognitive Outcomes in Patients with Chronic Temporal Lobe Epilepsy

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.

Focal Epileptiform Spikes in Conjuction With K-Complexes

Dyshormia or epileptiform spikes occurring within K-complexes have been described in patients with generalized epilepsy, with one study reporting that generalized spikes occurred frequently in association with K-complexes. We report the rate of focal epileptiform spikes occurring within K-complexes in localization-related epilepsy. Presurgical or diagnostic long-term video-EEG results of 40 consecutive patients with epilepsy (13 patients with right temporal lobe epilepsy, 20 patients with left temporal lobe epilepsy, and 7 patients with frontal lobe epilepsy) were reviewed. Sleep samples were reviewed and the numbers of K-complexes, spikes, and spikes within K-complexes were recorded. The comparison group consisted of 40 consecutive patients with nonepileptic events who were monitored with long-term video EEG. Focal epileptiform spikes occurring within K-complexes occurred in 2 of 13 (15%) patients with right temporal lobe patients, 6 of 20 (30%) patients with left temporal lobe, and 3 of 7 (42%) patients with extratemporal lobe epilepsy. In most patients, spikes occurring during K-complexes were rare. We identified spikes occurring during K-complexes in patients with localization-related epilepsy. The sharply contoured components of K-complexes or associated sleep spindles may obscure focal spikes within K-complexes. Nevertheless, K-complexes may be associated with focal epileptiform discharges.

Spatial relationship of source localizations in patients with focal epilepsy: Comparison of MEG and EEG with a three spherical shells and a boundary element volume conductor model

Epilepsy surgery is an option for patients with pharmacoresistant focal epilepsies, but it requires a precise focus localization procedure. Magnetoencephalography (MEG) and electroencephalography (EEG) can be used for analysis of interictal activity. The aim of this prospective study was to compare clusters of source localization results with MEG and EEG using a three spherical shells (3SS) and a boundary element method (BEM) volume conductor model. The study was closed when 100 patients met the inclusion criteria. Simultaneous MEG and EEG were recorded during presurgical evaluation. Epileptiform signals were analyzed using an equivalent current dipole model. Centroids of source localizations from MEG, EEG, 3SS, and BEM in their respective combinations were compared. In a 3SS model, MEG source localizations were 5.6 mm inferior to those obtained by EEG, while in a BEM model MEG source localizations were 6.3 mm anterior and 4.8 mm superior. The mean scattering of source localizations between both volume conductor models was 19.5 mm for EEG and 9.6 mm for MEG. For MEG no systematic difference between BEM and 3SS source localizations was found. For EEG, source localizations with BEM were 5.9 mm posterior and 11.7 mm inferior to those determined using 3SS. No differences were found between the 46 temporal and the 54 extratemporal lobe epilepsy patients. The observed systematic differences of source localizations of epileptic spikes due to the applied source signal modality and volume conductor model should be considered in presurgical evaluation when only one source signal and volume conductor model is available.

Value and Limitations of Seizure Semiology in Localizing Seizure Onset

Seizure semiology has been the foundation of clinical diagnosis of seizure disorders. This article discusses the value and the limitations of behavioral features of seizure episodes in localizing seizure onset. Studies have shown that some semiologic features of seizures are highly accurate in the hemispheric lateralization and lobar localization of seizures. There is good agreement between blinded reviewers in lateralizing video-recorded seizures in temporal lobe and extratemporal lobe epilepsies. However, seizure semiology alone should not be used to determine the site of seizure onset. Each semiologic feature may falsely localize seizure onset. Seizure semiology in some patients may signify the site of seizure propagation rather than origination. Moreover, seizure semiology may not be as reliable in multifocal epilepsies as it is in unifocal epilepsies. Many semiologic features of seizures of adults are often missing in seizures of children. Seizure semiology should be analyzed and integrated with EEG and neuroimaging data to localize the seizure focus. A sample of the recorded seizures should be shown to the patient's relatives or friends to verify that it is representative of habitual seizures.

Speech Recognition Impairments in Patients with Intractable Right Temporal Lobe Epilepsy

To evaluate speech recognition in patients with focal intractable epilepsy and surgical resections in the nondominant (right) hemisphere. Speech recognition was tested prospectively, under different listening conditions, in 22 patients with right temporal lobe (11 patients) or extra-temporal lobe epilepsy. All were left-hemisphere dominant for language on preoperative intracarotid sodium amobarbital testing. All patients demonstrated normal auditory recognition of words and environmental sounds before and after surgery. However, when real-world listening conditions were simulated by using acoustically degraded (filtered) words, patients with temporal lobe epilepsy performed significantly worse than patients with frontal or parietooccipital lobe epilepsy before and after surgery (p<0.0001). Patients with intractable right temporal lobe epilepsy are at risk for speech recognition impairments in real-world listening environments, independent of surgery. The impact of speech recognition difficulties on verbal communication, coupled with the prevalence of adverse listening environments, underscores the importance of testing speech recognition under different listening conditions in patients with intractable right temporal lobe epilepsy.