Mesiotemporal Lesions Research Articles

Mimics of Autoimmune Encephalitis: Validation of the 2016 Clinical Autoimmune Encephalitis Criteria.

The clinical criteria for autoimmune encephalitis (AE) were proposed by Graus et al. in 2016. In this study, the AE criteria were validated in the real world, and common AE mimics were described. In addition, criteria for probable anti-LGI1 encephalitis were proposed and validated. In this retrospective cohort study, patients referred to our national referral center with suspicion of AE and specific neuroinflammatory disorders with similar clinical presentations were included from July 2016 to December 2019. Exclusion criteria were pure cerebellar or peripheral nerve system disorders. All patients were evaluated according to the AE criteria. In total, 239 patients were included (56% female; median age 42 years, range 1-85). AE was diagnosed in 104 patients (44%) and AE mimics in 109 patients (46%). The most common AE mimics and misdiagnoses were neuroinflammatory CNS disorders (26%), psychiatric disorders (19%), epilepsy with a noninflammatory cause (13%), CNS infections (7%), neurodegenerative diseases (7%), and CNS neoplasms (6%). Common confounding factors were mesiotemporal lesions on brain MRI (17%) and false-positive antibodies in serum (12%). Additional mesiotemporal features (involvement extralimbic structures, enhancement, diffusion restriction) were observed more frequently in AE mimics compared with AE (61% vs 24%; p = 0.005). AE criteria showed the following sensitivity and specificity: possible AE, 83% (95% CI 74-89) and 27% (95% CI 20-36); definite autoimmune limbic encephalitis (LE), 10% (95% CI 5-17) and 98% (95% CI 94-100); and probable anti-NMDAR encephalitis, 50% (95% CI 26-74) and 96% (95% CI 92-98), respectively. Specificity of the criteria for probable seronegative AE was 99% (95% CI 96-100). The newly proposed criteria for probable anti-LGI1 encephalitis showed a sensitivity of 66% (95% CI 47-81) and specificity of 96% (95% CI 93-98). AE mimics occur frequently. Common pitfalls in AE misdiagnosis are mesiotemporal lesions (predominantly with atypical features) and false-positive serum antibodies. As expected, the specificity of the criteria for possible AE is low because these criteria represent the minimal requirements for entry in the diagnostic algorithm for AE. Criteria for probable AE (-LGI1, -NMDAR, seronegative) and definite autoimmune LE are applicable for decisions on immunotherapy in early disease stage, as specificity is high.

The spatial relationship between the MRI lesion and intraoperative electrocorticography in focal epilepsy surgery.

MRI and intraoperative electrocorticography are often used in tandem to delineate epileptogenic tissue in resective surgery for focal epilepsy. Both the resection of the MRI lesion and tissue with high rates of electrographic discharges on electrocorticography, e.g. spikes and high-frequency oscillations (80-500 Hz), lead to a better surgical outcome. How MRI and electrographic markers are related, however, is currently unknown. The aim of this study was to find the spatial relationship between MRI lesions and spikes/high-frequency oscillations. We retrospectively included 33 paediatric and adult patients with lesional neocortical epilepsy who underwent electrocorticography-tailored surgery (14 females, median age = 13.4 years, range = 0.6-47.0 years). Mesiotemporal lesions were excluded. We used univariable linear regression to find correlations between pre-resection spike/high-frequency oscillation rates on an electrode and its distance to the MRI lesion. We tested straight lines to the centre and the edge of the MRI lesion, and the distance along the cortical surface to determine which of these distances best reflects the occurrence of spikes/high-frequency oscillations. We conducted a moderator analysis to investigate the influence of the underlying pathology type and lesion volume on our results. We found spike and high-frequency oscillation rates to be spatially linked to the edge of the MRI lesion. The underlying pathology type influenced the spatial relationship between spike/high-frequency oscillation rates and the MRI lesion (P spikes < 0.0001, P ripples < 0.0001), while the lesion volume did not (P spikes = 0.64, P ripples = 0.89). A higher spike rate was associated with a shorter distance to the edge of the lesion for cavernomas [F(1,64) = -1.37, P < 0.0001, η 2 = 0.22], focal cortical dysplasias [F(1,570) = -0.25, P < 0.0001, η 2 = 0.05] and pleomorphic xanthoastrocytomas [F(1,66) = -0.18, P = 0.01, η 2 = 0.09]. In focal cortical dysplasias, a higher ripple rate was associated with a shorter distance [F(1,570) = -0.35, P < 0.0001, η 2 = 0.05]. Conversely, low-grade gliomas showed a positive correlation; the further an electrode was away from the lesion, the higher the rate of spikes [F(1,75) = 0.65, P < 0.0001, η 2 = 0.37] and ripples [F(1,75) = 2.67, P < 0.0001, η 2 = 0.22]. Pathophysiological processes specific to certain pathology types determine the spatial relationship between the MRI lesion and electrocorticography results. In our analyses, non-tumourous lesions (focal cortical dysplasias and cavernomas) seemed to intrinsically generate spikes and high-frequency oscillations, particularly at the border of the lesion. This advocates for a resection of this tissue. Low-grade gliomas caused epileptogenicity in the peritumoural tissue. Whether a resection of this tissue leads to a better outcome is unclear. Our results suggest that the underlying pathology type should be considered when intraoperative electrocorticography is interpreted.

Natural Course, Clinical Profile, and Treatment Strategies for Cerebral Cavernous Malformations

A large body of evidence has suggested that the natural biology for symptomatic cerebral cavernous malformations (CCMs) is dynamic. These lesions exhibit a temporal clustering epiphenomenon and usually manifest with multispectral clinical patterns, the most relevant being hemorrhagic and seizurogenic events. Most patients with cerebral cavernous malformations are asymptomatic, and the lesions are detected as incidentalomas. However, association with the CCM3 gene, Zabramski type I and II lesions, and brainstem location have the propensity toincrease the bleeding events. The rebleeding risk is 20%/year per lesion, which supports the need for surgical strategies for brainstem cavernous malformations; paradoxically, almost 50% of these patients develop new deficits postoperatively. A navigation-aided approach through safe entry zones is therefore of paramount importance in mitigating the surgical risks. Radiosurgery is currently reserved for biologically aggressive lesions that are not amenable for excision. Similarly, antiepileptic drug treatment is advised following the index seizure event. Early resection of the astrogliotic tissue, barring tissues within the brainstem, following detailed seizure semiology may be beneficial to patients with mesiotemporal lesions and in patients with noncompliance and severe adverse reactions to antiepileptic drug treatment. The proper dichotomization of symptomatic and high-risk cohorts and implementation of stringent surgical strategies performed by experienced surgeons result in good surgical outcomes. The guidelines from the Angioma Alliance Scientific Advisory Board Clinical Experts Panel greatly facilitate in formulating the proper management algorithm.

Transient global amnesia and focal diffusion weighted imaging lesions in mesiotemporal region: A ten-year experience

ObjectiveTo determine prevalence and characteristics of mesiotemporal diffusion weighted imaging (DWI) lesions in transient global amnesia (TGA), and to determine prevalence of “missed” DWI lesions on routine radiological reporting. MethodsThis is a retrospective study of patients with TGA admitted to a tertiary care hospital over ten years. Patients with TGA, who underwent magnetic resonance imaging (MRI) of the brain within one week of index event, were included in this study. MRI’s were reviewed by two independent raters. Clinical data and other investigations were collated. ResultsOf the 55 patients of TGA, 19 (35 %) had hyperintense DWI lesions with concordant apparent diffusion coefficient (ADC) hypointensity in the mesiotemporal region. Fifteen out of 19 (79 %) had unilateral lesions (6 left, 9 right). Twelve out of 19 DWI lesions were reported at the time of index scan. The false negative reporting rate was 36.8 %. DWI slice thickness (5 mm versus 3 mm), MRI machine strength (1.5 versus 3 T) and time interval from symptom onset to MRI brain (>24 h versus ≤ 24 h) were not significantly different between patients with or without DWI lesions and as well between patients with DWI lesions missed and initially reported at the time of index scan. ConclusionPunctuate DWI mesiotemporal lesions in TGA are prone to under-reporting. These lesions need to be categorically searched for at the time of reporting MRI Brain.

The effects of insular and mesiotemporal lesions on affective information processing: Preliminary evidence from patients with epilepsy surgery

Depressive symptoms and anxiety are common complaints in patients who have had epilepsy surgery. Recent studies have reported disturbances in emotional memory, facial and vocal emotion recognition, and affective learning after temporal lobe and/or insular resection for drug-resistant seizures, suggesting that these regions may be involved in emotional processes underlying psychological symptoms. The insula is a core component of the salience network and is thought to be involved in processing emotions such as disgust, and the role of mesial temporal lobe structures in affective processing is well established. However, to our knowledge, no study has yet investigated whether attentional processing of affective information is altered when these structures are resected as part of an epilepsy surgery. The present study examined the interference control capacity and attentional biases for emotional information in adult patients with epilepsy who underwent temporal lobe resections including the amygdala and hippocampus (n = 15) and/or partial or complete insular resections (n = 16). Patients were tested on an Emotional Stroop test and on a Dot-Probe task using fearful and disgusting pictures and were compared with a healthy control group (n = 30) matched for age, gender, and education. Repeated-measures analyses of variances revealed a significant effect of emotional words on color naming speed in the Emotional Stroop task among insular patients, which was not observed in the other groups. By contrast, the groups did not differ on Dot-Probe task performance. These preliminary findings suggest that insular damage may alter emotional interference control.

Long-term outcome characteristics in mesial temporal lobe epilepsy with and without associated cortical dysplasia

ObjectThe intention of our study was to identify predictive characteristics for long-term seizure control and running down phenomenon after surgical treatment of pharmacoresistant mesiotemporal lobe epilepsy (mTLE) with and without associated cortical dysplasia. Materials and methodsOur study comprises a consecutive series of 458 patients who underwent surgical treatment for intractable mTLE at the Epilepsy Center Freiburg. Data evaluated included semiology, duration and frequency of seizures, results of presurgical diagnostics including video-EEG monitoring, MRI, PET and SPECT as well as postoperative seizure outcome. Results were evaluated forming two groups: Group A consisted of isolated mesiotemporal lesions. Group B comprised patients with mTLE and additional focal cortical dysplasia (FCD). Statistical evaluation was based on the Kaplan Meier survival analysis, using log-rank-tests and a multivariate regression model. Postoperative running down phenomenon was defined as seizure freedom after a period of gradual reduction of postoperative seizure frequency. This was compared to patients with ongoing epilepsy. ResultsComplete seizure freedom was achieved in 65.0% of investigated patients at 1year and in 56.5% at long-term follow-up of ≥5 years after surgery. Corresponding results were 64.2% and 56.8% at 1 and ≥5 years, respectively in group A and 66.4% and 56.0%, respectively in group B. Predictive for favorable postoperative outcome in the total group were younger age at surgery, shorter duration of epilepsy, absence of secondarily generalized tonic-clonic seizures (SGTCS), presence of strictly ipsilateral temporal interictal epileptiform discharges (IEDs), complete resection of the lesion as well as absence of postoperative epileptiform activity and of early postoperative seizures. In subgroup analyses, patients of group A demonstrated longer postoperative seizure-free intervals with adolescent age at surgery, short duration of epilepsy before surgery and absence of SGTCS, whereas in patients of group B ipsilateral temporal seizure onset and strictly unilateral IEDs in EEG as well as complete resection were predictors for favorable seizure outcome. Furthermore, absence of early postoperative seizures and of spikes in EEG were predictive factors for long-term seizure-freedom in both subgroups.The running down phenomenon was found in 33 (7.2%) patients. None of the parameters evaluated demonstrated significant predictive power. Only late seizure onset and neoplastic lesions showed a trend for postoperative gradual seizure reduction in multivariate analyses. ConclusionDepending on the presence or absence of focal cortical dysplasia in addition to mesiotemporal structural alterations, predictors of long-term seizure control differed regarding the relevant clinical and electrophysiological features. This is important for specific patient counseling in respective groups.

Lésions mésiotemporales gauches et amnésie antérograde : un cas de neurosyphilis

Introduction Neurosyphilis has become uncommun in the developed countries. Observation We report a case of neurosyphilis with limbic presentation, left mesiotemporal lesions on MRI and severe anterograde amnesia. Discussion Pathogeneses of MRI findings are unknown. We suggest the implication of arteritis wich affects small vessels, parenchymatous and excitotoxic lesions. The absence of mesiotemporal lesion in immunodeficient patients, the limbic systematization of pathology underlines the involvement of probably auto-immune process. Neurosyphilis should always be considered in the differential diagnosis of limbic encephalitis in order to initiate treatment and to prevent cognitives sequelaes. At last, partial status epilepticus should be diagnosed and excitotoxicity lesions prevents with antiepileptic treatment.

Seizure intractability in patients with mesial temporal lobe epilepsy caused by hippocampal sclerosis as compared to mesiotemporal cavernomas

Introduction: The success of drug treatment is associated to the epilepsy syndrome and the underlying pathology, hippocampal sclerosis being an important risk factor for seizure recurrence. However, other mesiotemporal lesions like mesiotemporal cavernomas are also associated with a higher risk of intractability as compared to patients with extra-mesiotemporal lesions. The aim of the present study was to evaluate differences in seizure control as well as seizure semiology in patients with mesial temporal lobe epilepsy (MTLE) caused by either hippocampal sclerosis or cavernomas.

Surgical Treatment for Refractory Temporal Lobe Epilepsy in the Elderly: Seizure Outcome and Neuropsychological Sequels Compared with a Younger Cohort

Surgical treatment of refractory temporal lobe epilepsy (TLE) is promising for selected patients, but only little experience has been acquired in operating on older patients, especially with limited resections. We intend to delineate clinical and surgical factors influencing outcome in patients older than 50 years at operation and to compare the results with those of a younger patient cohort. Fifty-two patients older than 50 years were operated on for intractable mesial or combined mesiolateral TLE between 1991 and 2002. The mean age at operation was 55 years, and the mean duration of epilepsy was 33 years. Forty selective amygdalohippocampectomies (33 for hippocampal sclerosis, seven for removal of a mesiotemporal lesion), five lateral temporal lesionectomies plus amygdalohippocampectomy, and seven anterior temporal lobectomies were performed. Eleven (21%) patients had undergone invasive presurgical video-EEG monitoring. The mean follow-up period was 33 months. We compared the results with those of a younger cohort operated on in the same time period. Thirty-seven older patients attained complete seizure control (71% class I), and 10 patients had only rare postoperative seizures (19% class II). Four patients improved >75% (8% class III), and one patient did not improve (2% class IV). The same rate of seizure control was attained by 11 patients older than 60 years at surgery. These results were not significantly different from those in a younger patient group. A trend toward better seizure control was noted in 16 patients with an epilepsy duration of <30 years (all class I or II), and in 20 patients with a seizure frequency of fewer than five seizures per month (all class I or II). No mortality resulted from a total of 65 diagnostic and therapeutic procedures. A 3.8% permanent neurologic morbidity (dysphasia and hemiparesis) was noted. Hemianopia occurred in three (5.9%) patients. Neuropsychological testing revealed low preoperative performances and some gradual further deterioration after surgery. Results of surgery for TLE with mainly limited resections are promising in patients older than 50 years and older 60 years, despite the long seizure history. As expected, the risk of complications is somewhat higher compared with that in a younger control group. The impact of low neuropsychological performance is a concern.

Reply to Dr. Scheid’s Letter to the Editor regarding “Differential diagnosis of mesiotemporal lesions: case report of neurosyphilis”

Sir, We read with much interest the letter from Dr. Scheid regarding our article [1] and we fully agree that Lyme disease is part of the differential diagnosis of neurosyphilis. The hypothesis was considered in our case but excluded by clinical and laboratory examination. The first VDRL test was positive on serum and negative on CSF, which is why the patient had a second lumbar puncture 6 days later. This tested positive for both VDRL and TPHA. Serum and CSF tests became negative after

Differential diagnosis of mesiotemporal lesions: case report of neurosyphilis

Sir, The September issue of Neuroradiology contained an interesting article by Vieira Santos et al. entitled “Differential diagnosis of mesiotemporal lesions: case report of neurosyphilis” [1]. Coincidentally, a paper by us on the same subject (the differential diagnosis of neuroradiologically apparent medial temporal lobe abnormalities [2]) was published in the September issue of the Journal of Neurology. As an author of the latter paper, I would like to make some remarks on the case report by Vieira Santos et al. [1]. The authors state that medial temporal lobe involvement in neurosyphilis had previously been described in only four patients. However, this statement is incorrect. First, the cited article by Kanamalla et al. does not include such a finding in the context of neurosyphilis. Second, as we document [2], although medial temporal lobe involvement in neurosyphilis can still be regarded as rare, it is not as rare as the authors suggest. In addition to the case report of Vieira Santos et al., as well as a report that was recently published in Neurology [3], at least 16 patients with this neuroimaging pattern can be found in the literature. With respect to its pathogenesis, we have already pointed out that the assumption of a meningovascular origin is questionable [2]. We would like to pose the questions: how do the authors interpret the discordant results of the serologic and CSF tests in syphilis and, as a result, which stage of syphilis do they see in their patient? Finally, the differential diagnosis of the clinical signs and symptoms of the patient include Lyme neuroborreliosis. Borrelia burgdorferi is well known as a confounder of serologic tests in syphilis [4]. As penicillin G may be a satisfactory treatment alternative in neuroborreliosis [5], the response to this kind of treatment cannot be regarded as a sufficient criterion of differentiation. We therefore ask whether the authors ruled out Lyme neuroborreliosis in this patient.

Neuro‐Behçet's disease presenting initially as mesiotemporal lesions mimicking herpes simplex encephalitis

Received 8 July 2004 Accepted 15 July 2004 Sir, Nervous system involvement in Behcet’s disease (BD), usually called neuro-Behcet’s disease (NBD), is one of the most serious complications of the disease. Here we report an unusual case of NBD initially presenting as a generalized seizure with bilateral mesiotemporal lesions, which are commonly affected by herpes simplex or paraneoplastic limbic encephalitis. A 24-year-old man had a generalized convulsion with an unpleasant olfactory

Differential diagnosis of mesiotemporal lesions: case report of neurosyphilis

We report a clinical and imaging case of suspected herpes simplex encephalitis subsequently diagnosed as neurosyphilis based on positive antibodies in the CSF. MRI of the brain showed cortical and subcortical lesions in the mesial temporal region, septal area, insula and cingulated gyrus of the right cerebral hemisphere. Neurosyphilis should be included in the differential diagnosis of mesial temporal region lesions on MRI.

Persistent severe amnesia due to seizure recurrence after unilateral temporal lobectomy

Anterograde amnesia is a severely disabling state which has been reported as a consequence of bilateral mesiotemporal lesions in humans. In the present paper, recurrent epileptic seizures after temporal lobectomy are described as a rare cause of severe amnesia in two patients. Diffusion-weighted MRI in one patient showed cytotoxic edema during a nonconvulsive status epilepticus and subsequent progressive hippocampal atrophy within the following month. In the other patient, repeated conventional MRI revealed no structural abnormalities in the contralateral temporal lobe.

A 51-year-old woman with disorientation and amnesia

A previously healthy 51-year-old woman was admitted to hospital in April, 1999, with acute disorientation and amnesia. Physical examination was normal, except for a fresh right parietal scalp wound. On neurological examination, she was found to have severe verbal memory impairment. There were no signs of meningeal irritation. Creatinine phosphokinase was 2200 IU/L, Creactive protein was 3·1 mg/dL. Computed tomography of her head was normal. Cerebrospinal fluid (CSF) was clear, with 0·46 g/L protein, 23 white cells/mm (80% lymphocytes), 39 red cells/mm, normal glucose, lactate 24·9 mg/dL. Electroencephalogram (EEG) showed discontinuous pseudoperiodic paroxysmal discharges affecting mainly the left temporal lobe. It was considered that she may have had an epileptic seizure due to herpes simplex virus (HSV) encephalitis. Intravenous acyclovir (30 mg/kg daily) and oral valproate (600 mg daily) were given. Intravenous amoxicillin 6 g daily was also given to prevent infection of her head wound. Our confidence in the diagnosis of HSV encephalitis was reinforced by the results of magnetic resonance imaging (MRI) showing bilateral mesiotemporal lesions, predominant on the left side (figure) and by the demonstration of a left temporal focus of increased uptake on the Tc-99m HMPAO brain single-photon emission computed tomography (SPECT). Assay of CSF for HSV 1 and HSV 2 DNA by PCR was negative, which prompted us to consider an alternative diagnosis of lymphocytic meningoencephalitis. We looked for a rise in CSF antibody titre for HSV.

Transsulcal approach to mesiotemporal lesions. Anatomy, technique, and report of three cases.

Surgical resection of mesiotemporal lesions, particularly those in the dominant hemisphere, is often challenging. Standard approaches require excessive brain retraction, removal of normal cortex, or manipulation of the middle cerebral artery branches. This report describes a transsulcal temporal approach to mesiotemporal lesions and its application in three patients. Gross-total resection of the lesion was accomplished in all cases. An anatomical cadaveric study was also performed to delineate the microsurgical anatomy of this approach. Precise knowledge of temporal intraventricular landmarks allows navigation to the lesion without the need for a navigational system. This approach is helpful for neurologically intact patients with mesiotemporal lesions.