Surgical Treatment Of Temporal Lobe Epilepsy Research Articles

Surgical treatment may improve depressive and hysterical traits in temporal lobe epilepsy with hippocampal sclerosis: Study using the Minnesota Multiphasic Personality Inventory

AbstractAimThe influence of surgeries on psychiatric symptoms and personality traits is not well known in patients with intractable temporal lobe epilepsy (TLE). We investigated changes in personality traits with respect to postoperative seizure outcomes, etiology, side of surgery, and sex differences.MethodsClinical information was retrospectively collected for 44 patients whose Minnesota Multiphasic Personality Inventory (MMPI) was examined before and 1 year after surgical treatment for drug‐resistant TLE. Postoperative changes in MMPI T‐scores were analyzed using a paired t‐test. Participants were divided into two groups based on postoperative seizure outcome, the presence or absence of hippocampal sclerosis (HS) as the etiology, side of surgery, and sex differences. The effect of these clinical factors on postoperative changes in MMPI T‐scores was evaluated using analysis of covariance (P‐values < 0.05).ResultsThe hypochondria (Hs) scale decreased significantly in all patients (p = 0.022). The postoperative seizure‐free group had a significant decrease in the depression (D) scale (p = 0.037). The HS group had significant decreases in the D scale and the hysteria (Hy) scale (p = 0.016 and 0.004, respectively), and a significant increase in the masculinity‐femininity (Mf) scale (p = 0.009). No significant differences existed between the sides of surgery or sex.ConclusionDepressive traits were improved in patients with postoperative seizure freedom. Depressive and hysterical traits were improved in patients with HS, which may be attributed to a reduction in anxiety and fear associated with aura. Most personality traits are not significantly changed or exacerbated by surgical treatment of TLE.

Long-Term Surgical Outcomes and Predictors of Surgical Treatment in Temporal Lobe Epilepsy

Background: Surgical treatment of epilepsy is a favored modality in the management of refractory temporal lobe epilepsy (TLE) and known to be quite effective. The aim of this study was to evaluate the long-term outcomes in surgical treatment of TLE and to identify prognostic factors influencing postoperative seizure remission. Materials and Methods: The patients who underwent anterior temporal lobectomy (ATL) with the diagnosis of refractory TLE in our center between the years of 2006 and 2020 were included. Preoperative workup process was carried out by a multidisciplinary team and consisted of neuropsychological examination, long-term electroencephalography, brain magnetic resonance imaging (MRI), and fluorodeoxyglucose positron emission tomography (FDG-PET) for each patient. Postoperative assessment of seizure control was repeated every year following surgery and categorized according to Engel's outcome classification. The predictive value of baseline demographic, clinical, laboratory, imaging, and histopathological parameters on postoperative seizure control was also evaluated. Results: One hundred and forty-three patients who underwent ATL with the diagnosis of TLE were included. According to Engel's classification, the seizure freedom rate was found to be 83.2% at the 2nd year, 81.3% at the 4th year, and 79.2% at the 10th year after surgery. In the univariate analysis, febrile seizure (FS) history, unilateral interictal epileptiform discharges (IEDs), hippocampal sclerosis (HS) on MRI, unilateral temporal hypometabolism (HM) on FDG-PET, and HS in histopathology were predictors of seizure control at the postoperative 2nd and 10th years. FS history, unilateral localization of IEDs, and unilateral FDG-PET findings of temporal HM were found to be the independent predictors of postoperative seizure control on multivariate analysis. Conclusions: In the current study, we revealed that epilepsy surgery provides effective seizure control and represents a beneficial therapeutic option in refractory TLE. Our results also suggested that FS history, unilateral IEDs, and unilateral FDG-PET findings of temporal HM were independent predictors of seizure remission in these patients.

Double dissociation of selective recollection and familiarity impairments following two different surgical treatments for temporal-lobe epilepsy

Research has firmly established that the integrity of the medial temporal lobe (MTL) is critical for recognition memory. This ability is supported by recollection, which involves recovery of contextual details of a past stimulus encounter, and familiarity assessment, which leads to awareness of prior occurrence without such recovery. Dual-process models of MTL organization posit that recollection and familiarity are supported by the hippocampus and perirhinal cortex, respectively. Alternatively, it has been argued that both structures support these recognition processes similarly as part of a more integrated declarative memory system; from this perspective, reported selective recollection impairments with circumscribed hippocampal lesions may reflect differential sensitivity to overall memory strength, rather than a deficit in a distinct recognition process. Findings from past neuropsychological research remain inconsistent and controversial, in part due to biases in patient selection, variability in clinical etiology, and limited lesion documentation. Here, we administered a verbal recognition-memory task in combination with remember-know judgements to 10 individuals who had undergone left- or right-sided stereotactic amygdalo-hippocampotomy as a surgical treatment for intractable temporal-lobe epilepsy. Comparisons with healthy control participants revealed isolated impairments in recollection with preserved familiarity, regardless of hemispheric site of lesion. In addition, we show that this impairment can be observed at a comparable level of memory strength (i.e., overall recognition performance) as the selective familiarity impairment we previously described in N.B. – an individual who underwent a tailored surgical resection of the left anterior temporal lobe with hippocampal sparing for treatment of temporal-lobe epilepsy. By revealing a double dissociation concerning temporal-lobe mechanisms for recollection and familiarity, this evidence argues against a unitary, strength-based account of MTL organization.

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.

Sailing into the 21st Century: Magnetic Resonance Techniques in Epilepsy

The objective of the IIIrd International MagneticResonance and Epilepsy symposium was to discuss ourpresent knowledge of magnetic resonance (MR) tech-niques and their application to the study of human epi-lepsy. This symposium focused on three essential topics:the enhancement of imaging methods to improve lesiondetection in patients with epilepsy, the application ofmetabolic imaging using MR spectroscopy, and finally,investigation of functional techniques such as functionalMRI (fMRI) combined with EEG and MR diffusion-weighted imaging (DWI) and perfusion-weighted imag-ing techniques to examine functional changes for thedetection of abnormalities in patients with epilepsy.As in any other medical field, knowledge of epilepsy,its diagnosis, and its treatment has developed in succes-sive stages based on clinical observation and intuitioncoupled with technologic advances (1). The preeminenceof EEG as the essential laboratory investigation in thestudy of epilepsy has now been diminished by the intro-duction of modern neuroimaging techniques, particularlyMRI (2–4). This has become even more apparent in thelast few years with the addition of further noninvasiveneuroimaging techniques, such as positron emission to-mography (PET), magnetic resonance spectroscopy(MRS), and magnetic source imaging (MSI), which havepermitted the detection of previously unsuspected pathol-ogy in a large number of patients with epilepsy (2,5–9).Furthermore, these modern neuroimaging techniques havefundamentally influenced the surgical treatment of epilepsybecause the need for invasive electrophysiologic techniqueshas decreased. The role of the lesion in epileptogenesis hasnow been reevaluated and is now well recognized.The importance of MRI is well known to all thosetreating patients with epilepsy. In 1997, the InternationalLeague Against Epilepsy Neuroimaging Commissionpublished the recommendations for neuroimaging of pa-tients with epilepsy (10). Among the recommendationsof the Commission is the one that all patients in whomepilepsy develops should have, in the ideal situation, ahigh-quality MRI. Application of this principle to allpatients with epilepsy, except for those with clear-cutidiopathic generalized epileptic syndromes, should never becompromised. It is clear that the rationale for neuroimagingin epilepsy is identification of pathology that can then dic-tate specific treatment strategies and also identification ofspecific etiologic substrates that can aid in the identificationand classification of specific epileptic syndromes (11,12).MRI can also predict the nature of structural pathology andmay be able to detect the presence of abnormalities distantfrom the putative epileptogenic region (13). This has led toelaboration of the concept of pseudolocalization, and therealization that seizures may appear to originate in oneregion while a structural abnormality may be present inanother region. Finally, there is sufficient evidence thatMRI is the most important predictor for successful surgicaltreatment of temporal lobe epilepsy (14,15).Although current MR techniques are able to detectpathology in many more patients with epilepsy than waspossible a few years ago, a large number of patients withepilepsy have normal MR studies. How can we improvethe detection capability of MR in epilepsy? Enhancedimaging can be achieved with techniques for improvingspatial resolution, image contrast, or both. These goalscan be achieved using phased-array surface coils, imageaveraging, or high-field-strength MRI (16). For example,surface coil imaging can add value to the examination inl50% of patients with normal MRIs in selected patientswith well-localized electroclinical syndromes. Similarly,image averaging can be used to improve the signal-to-noise ratio (SNR) of an MRI by performing several MRIstudies and spatially co-registering and then combiningthe images into a single study (17). Finally, high-fieldMR (3–8 T) can provide high SNR with the potential forimproved imaging. Experimental results show an ap-proximately linear increase in SNR with increasing fieldstrength. The expected increase in SNR with small voxelsize can provide improved imaging details. These tech-niques and examples of their potential applications aredescribed under high-resolution imaging.More than a decade ago, Jack et al. (18,19) introducedto the epilepsy community the use of hippocampal volu-metry for the quantitative determination of hippocampalatrophy in temporal lobe epilepsy. It is now clear thatalthough quantitative volumetric analysis of medial tem-

Outcome of Epilepsy Surgery in Patients with Temporal Lobe Epilepsy Associated with 3- to 4-Hz Generalized Spike and Wave Discharges

Generalized spike and wave discharges (GSW) occur in ∼10% of patients with temporal lobe epilepsy (TLE). However, whether the presence of GSW has an adverse effect on the outcome after surgical treatment for TLE is uncertain. We addressed this issue by reviewing the preoperative EEG of patients who had undergone temporal lobe surgery and had a minimum follow-up of 12 months. Four of 86 (5%) surgical patients showed GSW on preoperative interictal EEG. Their preoperative seizure types included both partial and generalized seizures. The proportion of patients with GSW who were seizure-free was no different from that of patients without GSW (50 and 54%, respectively). We found no evidence in this small sample that the presence of GSW is associated with a worse surgical outcome