Characteristics of bilateral versus unilateral temporal encephalocele-associated epilepsy

[Surgical treatment of focal drug-resistant epilepsy associated with temporal lobe encephalocele]

BACKGROUND

In recent years, temporal lobe encephalocele has become more common in patients with focal drug-resistant epilepsy. Despite available experience, there are still no clear recommendations for choosing the extent of surgery in these patients.

OBJECTIVE

To evaluate the effectiveness of diagnosis and surgical treatment of focal drug-resistant epilepsy associated with temporal lobe encephalocele.

MATERIAL AND METHODS

The study included 21 patients with focal temporal lobe epilepsy and temporal lobe encephalocele. All patients underwent continuous video-EEG monitoring and MRI of the brain. There were 12 (57.4%) selective encephalocele resections and 9 (42.6%) anterior temporal lobectomies. The median follow-up period was 31 months.

RESULTS

The overall effectiveness of surgical treatment with postoperative Engel class I was 76% (16 cases). Selective encephalocele resection was followed by postoperative Engel class I in 10 patients (83%). There were 6 (67%) patients with similar outcomes after temporal lobectomy. Mean volume of resected tissue adjacent to encephalocele was 8.3 cm3.

CONCLUSION

Surgery is a highly effective treatment for patients with epileptic seizures following temporal lobe encephalocele. In our sample, favorable postoperative outcomes were achieved in 76% of patients (Engel class I). There were no significant differences in effectiveness between selective resection and temporal lobectomy. Further research is necessary for a clear protocol of surgical treatment of focal drug-resistant epilepsy associated with encephalocele.

Distinctive electro-clinical, neuroimaging and histopathological features of temporal encephaloceles associated to epilepsy

OBJECTIVE

Encephaloceles (ENCs) may cause clinical complications, including drug-resistant epilepsy that can be cured with epilepsy surgery.

METHODS

We describe clinical, diagnostic, and neuropathological findings of 12 patients with temporal ENC and epilepsy evaluated for surgery and compare them with a control group of 26 temporal lobe epilepsy (TLE) patients.

RESULTS

Six patients had unilateral and 6 bilateral temporal ENCs. Compared to TLEs, ENCs showed i) later epilepsy onset, ii) higher prevalence of psychiatric comorbidities, iii) no history of febrile convulsions, and iv) ictal semiology differences. Seven patients had MRI signs of gliosis, and 9 of intracranial hypertension. Interictal EEG analysis in ENCs demonstrated significant differences with controls: prominent activity in the beta/gamma frequency bands in frontal regions, interictal short sequences of low-voltage fast activity, and less frequent and more localized interictal epileptiform discharges. Ictal EEG patterns analyzed in 9 ENCs showed delayed and slower contralateral spread compared to TLEs. All ENCs that underwent surgery (7 lobectomies and 1 lesionectomy) are in Engel class I. Neuropathological examination revealed 4 patterns: herniated brain fragments, focal layer I distortion, white matter septa extending into the cortex, and altered gyral profile.

CONCLUSIONS AND SIGNIFICANCE

The described peculiarities might help clinicians to suspect the presence of largely underdiagnosed ENCs.

The Predictors of Seizures in Patients with Encephalocele: An 11-Year Experience from a Tertiary Hospital

INTRODUCTION

The aim of the study was to investigate and identify the predictors associated with the incidence of seizures in patients with encephalocele (EC).

METHODS

A retrospective analysis was undertaken of patients treated for EC at a tertiary medical center in Tehran between 2010 and 2021. Data including age at presentation, gender, location, size, and content of EC, ventriculomegaly, hydrocephalus, associated anomalies, and neurodevelopmental delay (NDD) were evaluated for their prognostic value. In addition, univariate and multivariate analyses were performed to identify the correlation between independent predictors and seizure incidence.

RESULTS

One hundred and two cases of EC were identified. Seventy-one ECs (69.6%) were posterior ECs, while 31 (30.4%) were anterior. Neural tissue was found in 43 (42.2%) of the ECs. Thirty-three patients (32.4%) had ventriculomegaly, of which 90.9% underwent shunt placement for progressive or symptomatic hydrocephalus. Seizure was found in 26 (25.5%) patients. On univariate analysis, presence of other anomalies, postoperative infections, and NDD were associated with seizures (p < 0.05). When the anomalies were categorized into intracranial and extracranial groups in univariate analysis, none was associated with statistically significant increase in seizure (p values of 0.09 and 0.61, respectively). Although according to multivariate analysis, only the association between other associated anomalies and seizure was near significant (OR: 2.0, 95% CI: 0.95-4.2, p = 0.049). Children with NDD and postoperative infection were, respectively, 3.04 and 1.3 times more at risk to experience seizures compared to other patients.

CONCLUSION

We found a rate of 25.5% risk of seizure in patients with EC. This study could not find any significant predictors of seizure in children with EC. However, pediatric patients with postoperative infections including sepsis, wound infection, and NDD require more consideration to reduce the risk of seizure.

Temporal encephaloceles and coexisting epileptogenic lesions

OBJECTIVE

This study was performed to identify coexisting structural lesions in patients with epilepsy and known temporal encephaloceles (TEs).

METHODS

Forty-seven structural magnetic resonance imaging (MRI) scans of patients with epilepsy and radiologically diagnosed TEs were retrospectively reviewed visually and using an automated postprocessing software, the Morphometric Analysis Program v2018 (MAP18), to depict additional subtle, potentially epileptogenic lesions in the 3D T1-weighted MRI data. All imaging findings were evaluated in the context of clinical and electroencephalographical findings.

RESULTS

The study population consisted of 47 epilepsy patients (38.3% female, n = 18). The median age at the time of the scan was 40 years (range 12-81 years). Twenty-one out of 47 MRI scans (44.7%) showed coexisting lesions in the initial MRI evaluation; in 38.3% (n = 18) of patients, those lesions were considered probably epileptogenic. After postprocessing, probable epileptogenic lesions were identified in 53.2% (n = 25) of patients. Malformations of cortical development had initially been reported in 17.0% (n = 8) of patients with TEs, which increased to 38.3% (n = 18) after postprocessing. TEs and other epileptogenic lesions were considered equally epileptogenic in 21.3% (n = 10) of the cases in the initial MR reports and 25.5% (n = 12) of the cases after postprocessing.

SIGNIFICANCE

Temporal encephaloceles are a potential cause of MRI-negative temporal lobe epilepsy. According to our data, TEs can occur with other lesions, suggesting that increased awareness is also required in patients with lesional epilepsy. TEs may not always be epileptogenic; hence, their occurrence with other structural pathologies may influence the presurgical evaluation and surgical approach. Finally, TEs can be associated with malformations of cortical development, which may indicate a common developmental etiology of those lesions.

Headache characteristics among patients with epilepsy and the association with temporal encephaloceles

Purpose

Our aim was to determine if headaches characteristic of possible Idiopathic Intracranial Hypertension (IIH) and in general were more prevalent in patients with versus without temporal encephaloceles (TEs) among patients with epilepsy.

Methods

Electronic medical records were reviewed retrospectively. Among 474 patients with epilepsy, 103 patients (21.7%) had at least one TE diagnosed on initial MRI or on retrospective review by a board-certified neuroradiologist, while 371 patients had no TE present. The patients were grouped into one of four categories depending on their headache characteristics (IIH-like, peri-ictal, other, or no headaches). Analysis of the categories was performed using a Chi Square test.

Results

Patients with TEs were more likely to experience headaches of any type than no headaches and more likely to experience IIH-like headaches than to have other headaches or no headaches compared to patients without TEs. Interestingly, patients with TEs were also more likely to experience peri-ictal headaches compared to patients without TEs. However, patients with TEs were no more likely or unlikely to have other (non-IIH or peri-ictal) headaches vs no reported headaches and were not more or less likely to have elevated opening pressure.

Conclusion

On retrospective review, patients with TEs and epilepsy were more likely to exhibit headache features characteristic of IIH or to have peri-ictal headaches compared to epilepsy patients without TEs. These findings underscore the need for careful and thorough history of associated headaches in patients with epilepsy so that those patients at risk for TEs can undergo careful inspection of MRI to evaluate for their presence, which may represent a focus for seizures.

Idiopathic intracranial hypertension - a wider spectrum than headaches and blurred vision

BACKGROUND

The purpose of this study was to analyse less known clinical scenarios associated with idiopathic intracranial hypertension.

METHODS

The study involved analysis of magnetic resonance imaging signs of idiopathic intracranial hypertension in patients with spontaneous rhinoliquorrhoea (n = 7), in patients with temporal lobe epilepsy and surgically treated antero-inferior temporal lobe meningo-encephaloceles (n = 15), and in patients who developed clinical signs of idiopathic intracranial hypertension following the treatment of spontaneous intracranial hypotension (n = 7).

RESULTS

Three of six patients with spontaneous rhinoliquorrhoea and six of 15 operated patients with temporal lobe epilepsy due to temporal lobe meningo-encephaloceles showed magnetic resonance imaging signs of idiopathic intracranial hypertension and had a body mass index >30 kg/m². Rebound high pressure headaches and sings of idiopathic intracranial hypertension occurred in seven of 44 surgically treated spontaneous intracranial hypotension patients.

CONCLUSIONS

Magnetic resonance imaging findings should guide the clinician to consider (idiopathic) intracranial hypertension when patients develop spontaneous rhinoliquorrhoea, temporal lobe epilepsy secondary to temporal lobe meningoencephaloceles or high pressure headaches in spontaneous intracranial hypotension. Whether idiopathic intracranial hypertension must be regarded as a differential diagnosis or as a cause, or whether there are common pathophysiological pathways that lead to signs of idiopathic intracranial hypertension in this wider spectrum of disease is the focus of further study.

Encephalocele-Associated Drug-Resistant Epilepsy of Adult Onset: Diagnosis, Management, and Outcomes

Epileptogenic encephaloceles, most frequently located in the temporal lobe, are a known lesional cause of focal epilepsy. Data are limited regarding diagnosis, management, and outcomes of patients with epilepsy in the setting of an encephalocele, because the literature mostly comprises case reports, case series, and retrospective studies. We conducted a broad literature review for articles related to encephaloceles and epilepsy regardless of level of evidence. Hence, this review provides a summary of all available literature related to the topic. Thirty-six scientific reports that fulfilled our inclusion criteria were reviewed. Most reported patients presented with focal impaired awareness seizures and/or generalized tonic-clonic seizures. Although most of the encephaloceles were located in the temporal lobe, we found 5 cases of extratemporal encephaloceles causing epilepsy. More patients who underwent either lesionectomy or lobectomy were seizure free at time of follow-up. In the temporal lobe, there is no clear consensus on the appropriate management for epileptic encephaloceles and further studies are warranted to understand the associated factors and long-term outcomes associated with epilepsy secondary to encephaloceles. Reported data suggest that these patients could be manageable with surgical procedures including lesionectomy or lobectomy. In addition, because of data suggesting similar results between procedures, a more conservative surgery with lesionectomy and defect repair rather than a lobectomy may have lower surgical risks and similar seizure freedom.

Temporal encephaloceles in epilepsy patients and asymptomatic cases: Size may indicate epileptogenicity

OBJECTIVE

This study was undertaken to identify temporal encephaloceles (TEs) and examine their characteristics in patients with temporal lobe epilepsy (TLE) and extratemporal lobe epilepsy (ETLE), as well as in asymptomatic cases.

METHODS

Four hundred fifty-eight magnetic resonance imaging scans were examined retrospectively to identify TE in 157 patients with TLE, 150 patients with ETLE, and 151 healthy controls (HCs).

RESULTS

At least one TE was identified in 9.6% of the TLE patients (n = 15, 95% confidence interval [CI] = 5.3%-15.3%), in 3.3% of patients with ETLE (n = 5, 95% CI = 1.1%-7.6%), and in 2.0% of the HCs (n = 3, 95% CI = .4%-5.7%), indicating a significantly higher frequency in patients with TLE compared to ETLE and HC subjects (p = .027, p = .005). Examining the characteristics of TEs in both asymptomatic and epilepsy patients, we found that TEs with a diameter of less than 6.25 mm were more likely to be asymptomatic, with a sensitivity of 91.7% and a specificity of 73.3% (area under the curve = .867, 95% CI = .723-1.00, p = .001).

SIGNIFICANCE

Temporal encephaloceles may occur without presenting any clinical symptoms. Patients with TLE show a higher frequency of TEs compared to the ETLE and HC groups. According to our study, TE size could be used to suggest potential epileptogenicity.

Contributions of left and right anterior temporal lobes to semantic cognition: Evidence from patients with small temporopolar lesions

Decades of research have increased the understanding of the contribution of the anterior temporal lobes (ATLs) to semantic cognition. Nonetheless, whether semantic processing of different types of information show a selective relationship with left and right ATLs, or whether semantic processing in the ATLs is independent of the modality of the input is currently unknown. There exists evidence supporting each of these alternatives. A fundamental objection to these findings is that they were obtained from studies with patients with brain damage affecting extensive regions, sometimes bilaterally. In the current study, we assessed a group of 38 temporal lobe epilepsy (TLE) patients with either left or right small epileptogenic lesions with a battery of commonly used semantic tasks that tested verbal and non-verbal semantic processing. We found that left TLE patients exhibited worse performance than controls on the verbal semantic tasks, as expected, but also on the non-verbal semantic task. On the other hand, performance of the right TLE group did not differ from controls on the non-verbal task, but was worse on a semantic fluency task. When performance between patient groups was compared, we found that left TLE not only did worse than right TLE on the naming task, but also on the non-verbal associative memory task. When considered together, current data do not support a strong view of input modality differences between left and right ATLs. Additionally, they provide evidence indicating that the left and right ATLs do not make similar contributions to a singular functional system for semantic representation.

Anterior temporal encephaloceles: Elusive, important, and rewarding to treat

OBJECTIVE

To investigate the etiology and longitudinal clinical, neuropsychological, psychosocial, and surgical outcome profile of patients with medication refractory epilepsy and temporal encephaloceles with a view to highlight diagnostic clues and management strategies.

METHODS

The comprehensive epilepsy program databases at two surgical epilepsy centers from January 2000 to October 2018 were reviewed for this observational study, to identify patients with encephaloceles causing temporal lobe epilepsy (TLE) and treated with surgical resection. Their clinical, radiological, neuropsychological, psychiatric, and surgical data were obtained. Body mass index (BMI) data were also reviewed due to possible correlation between idiopathic intracranial hypertension and encephaloceles.

RESULTS

Thirteen patients (eight female) were identified; only three were recognized on initial magnetic resonance imaging (MRI) report. Temporal encephaloceles were identified on the left in eight patients, on the right in three patients, and bilaterally in two patients. One patient had a strong family history of encephaloceles. The median BMI for patients with seizure onset ≤20 years of age was 22.4, whereas for patients with onset >20 years median BMI was 32.6 (P = .06). Five patients underwent a focal lesionectomy, three patients had limited temporal lobectomy, and five patients had standard anterior temporal lobectomy. Median postoperative follow-up was 5.5 years. All but one patient were free of disabling seizures. Nine of ten neuropsychologically tested patients had no discernable cognitive decline postoperatively. Postoperative psychosocial adjustment features were present in four patients.

SIGNIFICANCE

Genetic factors and a possible association with idiopathic intracranial hypertension (given female predominance and elevated BMI) may contribute to the causation of temporal lobe encephaloceles. It is notable that a targeted surgical approach in the management of patients with TLE associated with encephaloceles has an excellent long-term clinical and neuropsychological outcome. Subtle encephaloceles should be actively searched for in patients with drug-resistant TLE because they significantly change surgical strategy and prognostication.