The clinical spectrum of epilepsy in children and adults with hypothalamic hamartoma

Advances in epileptic network findings of hypothalamic hamartomas

Hypothalamic hamartomas (HHs) are congenital developmental malformations located in the hypothalamus. They are associated with a characteristic clinical manifestation known as gelastic seizures (GS). However, the traditional understanding of HHs has been limited, resulting in insufficient treatment options and high recurrence rates of seizures after surgery. This is consistent with the network hypothesis of focal epilepsy that the epileptogenic zone is not only limited to HH but may also involve the distant cerebral cortex external to the HH mass. The epilepsy network theory, on the other hand, provides a new perspective. In this study, we aim to explore HH-related epilepsy as a network disease, challenging the conventional notion of being a focal lesional disease. We analyze various aspects of HHs, including genes and signaling pathways, local circuits, the whole-brain level, phenotypical expression in terms of seizure semiology, and comorbidities. By examining HHs through the lens of network theory, we can enhance our understanding of the condition and potentially identify novel approaches for more effective management and treatment of epilepsy associated with HHs.

Kindling in humans: Does secondary epileptogenesis occur?

The relevance of secondary epileptogenesis for human epilepsy remains a controversial subject decades after it was first described in animal models. Whether or not a previously normal brain region can become independently epileptogenic through a kindling-like process has not, and cannot, be definitely proven in humans. Rather than reliance on direct experimental evidence, attempts to answering this question must depend on observational data. In this review, observations based largely upon contemporary surgical series will advance the case for secondary epileptogenesis in humans. As will be argued, hypothalamic hamartoma-related epilepsy provides the strongest case for this process; all the stages of secondary epileptogenesis can be observed. Hippocampal sclerosis (HS) is another pathology where the question of secondary epileptogenesis frequently arises, and observations from bitemporal and dual pathology series are explored. The verdict here is far more difficult to reach, in large part because of the scarcity of longitudinal cohorts; moreover, recent experimental data have challenged the claim that HS is acquired consequent to recurrent seizures. Synaptic plasticity more than seizure-induced neuronal injury is the likely mechanism of secondary epileptogenesis. Postoperative running-down phenomenon provides the best evidence that a kindling-like process occurs in some patients, evidenced by its reversal. Finally, a network perspective of secondary epileptogenesis is considered, as well as the possible role for subcortical surgical interventions.

Neural network mapping of gelastic behavior in children with hypothalamus hamartoma

BACKGROUND

Hypothalamus hamartomas (HHs) are rare, congenital, tumor-like, and nonprogressive malformations resulting in drug-resistant epilepsy, mainly affecting children. Gelastic seizures (GS) are an early hallmark of epilepsy with HH. The aim of this study was to explore the disease progression and the underlying physiopathological mechanisms of pathological laughter in HH.

METHODS

We obtained clinical information and metabolic images of 56 HH patients and utilized ictal semiology evaluation to stratify the specimens into GS-only, GS-plus, and no-GS subgroups and then applied contrasted trajectories inference (cTI) to calculate the pseudotime value and evaluate GS progression. Ordinal logistic regression was performed to identify neuroimaging-clinical predictors of GS, and then voxelwise lesion network-symptom mapping (LNSM) was applied to explore GS-associated brain regions.

RESULTS

cTI inferred the specific metabolism trajectories of GS progression and revealed increased complexity from GS to other seizure types. This was further validated via actual disease duration (Pearson R = 0.532, P = 0.028). Male sex [odds ratio (OR) = 2.611, P = 0.013], low age at seizure onset (OR = 0.361, P = 0.005), high normalized HH metabolism (OR =  - 1.971, P = 0.037) and severe seizure burden (OR =  - 0.006, P = 0.032) were significant neuroimaging clinical predictors. LNSM revealed that the dysfunctional cortico-subcortico-cerebellar network of GS and the somatosensory cortex (S1) represented a negative correlation.

CONCLUSIONS

This study sheds light on the clinical characteristics and progression of GS in children with HH. We identified distinct subtypes of GS and demonstrated the involvement of specific brain regions at the cortical-subcortical-cerebellar level. These valuable results contribute to our understanding of the neural correlates of GS.

Epilepsy surgery in patients with hypothalamic hamartomas - Population-based two-year and long-term outcomes

OBJECTIVE

Hypothalamic hamartomas are benign lesions associated with drug resistant epilepsy. Surgical treatment has become an increasingly utilised approach with promising results. This study aims to evaluate seizure outcome and complications after surgery in a population-based series of patients with intractable epilepsy and hypothalamic hamartoma.

METHODS

All patients with hypothalamic hamartoma treated with epilepsy surgery in Sweden since 1995 with at least two years of follow-up were included. Preoperative, two-, five- and ten-year prospective longitudinal data were collected from The Swedish National Epilepsy Surgery Register. Data included seizure types and frequency, duration of epilepsy, clinical characteristics, neurological deficits, cognitive level and complications. In a subgroup from Gothenburg, we also analysed data not included in the register such as classification of hamartomas, surgical procedures and gelastic seizures.

RESULTS

Eighteen patients were operated on during the period 1995-2020. The median age at epilepsy onset was 6 months and age at surgery 13 years. Four were seizure free and another four had ≥75% reduction in seizure frequency at the two-year follow-up. Two of the 13 patients with a long-term follow-up (five or ten years) were seizure-free and four had ≥75% reduction in seizure frequency. Three had an increased seizure frequency. No major complications were seen. Five had minor complications. In the Gothenburg subgroup all had open pterional disconnection or intraventricular endoscopic disconnection. Six of 12 were free from gelastic seizures at the two-year follow-up and six of eight at the long-term follow-up.

CONCLUSION

This study supports surgical treatment of hypothalamic hamartomas as a safe method with a low risk of permanent complications. The seizure reduction seems to be persistent over time.

Epilepsy in hypothalamic hamartomas: semiology spectrum and predictor analyses of 78 patients

OBJECTIVE

To assess seizure semiology and disease evolution in a large number of hypothalamic hamartoma (HH) patients.

METHODS

Seizure semiology and associated medical records for 78 patients with HH-related epilepsy were retrospectively reviewed. Potential predictors of seizure types were assessed through univariate and binary logistic regression analyses.

RESULTS

57 (73.1%) patients presented with gelastic seizures at the onset of epilepsy, of whole 39 (68.4%) experienced additional seizure types with a mean latency interval of 4.59 years. Automatism, version, and sGTCs were increasingly common with disease evolution. The intraventricular size of HH was significantly negatively correlated with the disease evolution interval (r = -0.445, p = 0.009). A significantly higher rate of patients with automatism in the DF-II group relative to the DF-III group was found in both χ2 (X = 6.07, p = 0.014) and logistic regression analyses (B = 3.196, p = 0.020).

INTERPRETATION

Gelastic seizures are the most common initial seizure type in HH patients, but variable semiologies occur with disease evolution. The intraventricular HH lesion size is an important determinant of epilepsy evolution. DF-II HH lesions contribute to a higher chance of automatism evolution. The present study furthers our understanding of the dynamic organization of the seizure network affected by HH.

Stereotactic radiosurgery as the initial management option for small-volume hypothalamic hamartomas with intractable epilepsy: a 35-year institutional experience and systematic review

OBJECTIVE

Young patients with hypothalamic hamartomas (HHs) often present with intractable epilepsy. Currently there are no established management guidelines for HH. The authors retrospectively reviewed their single-institution experience to delineate the role of stereotactic radiosurgery (SRS).

METHODS

Seven patients with HHs (4 females; median age 13.7 years, range 2.5-25 years) with no prior resection underwent SRS between 1987 and 2022. The clinical history, epilepsy profile, radiographic findings, and neurological outcomes were characterized. HH topographical types were classified according to the Régis classification. Outcome measures included Engel seizure classification, HH response, and the need for additional surgical interventions.

RESULTS

All patients had Engel class IV epilepsy. A Leksell Gamma Knife was used to deliver a median margin dose of 18 Gy (range 16-20 Gy) to a median hamartoma volume of 0.37 cm3 (range 0.20-0.89 cm3). Seizure reduction was confirmed in 6 patients, and 2 patients had regression of their hamartoma. Two patients underwent resection and/or laser interstitial thermal therapy after SRS. At follow-up, 1 patient was seizure free, 4 patients achieved Engel class II, 1 patient had Engel class III, and 1 patient had Engel class IV seizure outcomes.

CONCLUSIONS

SRS as the initial management option for HH was associated with a low risk of adverse effects. In this institutional series reviewing small-volume HHs treated with SRS, no adverse radiation effect was detected, and the majority of patients experienced seizure reduction. SRS should be considered as the first-line treatment for seizure control in patients with small-volume HHs.

Forensically relevant challenging behaviors and the genetics domain

Impulsive and aggressive behaviors along with intellectual disabilities often manifest in the context of genetic disorders and are a persisting challenge to professionals in the forensic psychiatric and psychological setting. The following chapter comprises an overview of relevant factors in the gene-context-behavior interaction such as monoamine oxidase A activity and specific epileptic phenomena. It presents several examples of monogenetic disorders with behaviors from the aggression spectrum and summarizes emerging strategies for treatment and clinical management thereof. The final part focuses on challenges and future developments in this field with relevance for the judicial and forensic systems. It is concluded that the relationship between a genetic syndrome and forensically relevant and/or violent behaviors should typically be addressed within a multidisciplinary framework that also includes the application of modern genetic techniques.

Hypothalamic hamartoma associated with polymicrogyria and periventricular nodular heterotopia in children: report of three cases and discussion of the origin of the seizures

PURPOSE

Hypothalamic hamartomas (HH) are malformations responsible for drug-resistant epilepsy. HH are usually isolated or part of a genetic syndrome, such as Pallister-Hall. Exceptionally they can be associated with other brain malformations such as polymicrogyria (PMG) and periventricular nodular heterotopia (PNH). We discuss the origin of the seizures associated with this combination of malformations, through electrophysiological studies, and review the literature on this rarely reported syndrome.

METHODS

We retrospectively reviewed the patients with HH who had surgery between 1998 and 2020 and selected those with associated focal PMG and PNH, detected on MRIs. All patients had comprehensive clinical evaluation and surface video-EEG and one underwent stereoelectroencephalography (SEEG).

RESULTS

Three male patients out of 182 were identified with a mean age at surgery of 7.5 years. MRI showed unilateral focal PMG (fronto-insulo-parietal, fronto-insulo-parieto-opercular, and fronto-insular, respectively) and multiple PNH homolateral to the main HH implantation side. In two patients, there were strong clinical and scalp EEG arguments for seizure onset within the HH. In the third, due to abnormalities on scalp video-EEG in the same area as PMG and the lack of gelastic seizures, SEEG was indicated and demonstrated seizure onset within the hamartoma. With a mean follow-up of 6 years, two patients were seizure-free.

CONCLUSION

Our results show that HH is the trigger of epilepsy, which confirms the high epileptogenic potential of this malformation. In patients such as ours, as in those with isolated HH, we recommend to begin by operating the HH independently of seizure semiology or electrophysiological abnormalities.

Anatomical features decide the atypical seizure manifestation of parahypothalamic hamartomas

Background

The intrahypothalamic phenotype of hypothalamic hamartomas (HH) is associated with epilepsy, and the parahypothalamic phenotype usually leads to central precocious puberty but not neurological comorbidities or seizures. No study has confirmed the pathological role of parahypothalamic hamartomas in epileptogenesis, and the underlying mechanism is yet to be elucidated.

Objective

We aimed to investigate whether parahypothalamic hamartomas are intrinsically epileptogenic and elucidate the underlying pathway of epileptogenesis.

Methods

We reviewed 92 patients with HH-related epilepsy, categorized them by the classification system of Delalande and Fohlen, and further classified Type I (corresponding to parahypothalamic HH) into the following three groups based on the relationship between the lesion and mammillary bodies (MB): entirely invaded (Group 1), partially connected (Group 2), and not connected at all (Group 3). We examined different anatomical features with their relationship to clinical manifestations. Stereoelectroencephalography (SEEG) was implanted in both HH and extra-HH cortices in different groups to identify the epileptogenic zone. Corticocortical evoked potentials (CCEPs) were also used to determine the pathological correlation among different regions to determine the related epileptogenic network.

Results

A total of 13 patients presented with parahypothalamic HH and 10 (76.9%) presented with non-GS only, with late-onset age and normal cognitive development, which is different from classical clinical features. SEEG showed that HH is intrinsically epileptogenic in MB-involved parahypothalamic groups. No statistical difference was found in onset age (p = 0.213), and lesions horizontally oriented from the tuber cinereum without connection to MB were not involved in seizure genesis. CCEP indicated a pathological connection among HH, middle cingulate cortex, and insular cortex.

Conclusion

The parahypothalamic HH can also cause epilepsy and is different from classic HH-related seizures, by non-GS only with the late-onset age and normal cognitive development. MB is proven to be related to non-GS by the mamillo-cingulate-cortex pathway.

Stereoelectroencephalography-guided radiofrequency thermocoagulation for hypothalamic hamartoma: Electroclinical patterns and the relationship with surgical prognosis

BACKGROUND

Radiofrequency thermocoagulation (RFTC) guided by stereo-electroencephalography (SEEG) has been proved to be a safe method to reduce seizure frequency in patients with drug-resistant epilepsy. However, there are few reports addressing the value and safety of this procedure in hypothalamic hamartoma (HH).

OBJECTIVE

To present the results of our experience using SEEG-guided RFTC in HH patients with drug-resistant epilepsy, and identify outcome predictors.

METHODS

We retrospectively reviewed the clinical and surgical characteristics of 27 HH-related patients with epilepsy in our center between 2015 and 2019. All patients underwent invasive recordings with SEEG before RFTC was performed. We reported surgical outcome predictors and postoperative follow-up concerning safety and efficacy (mean follow-up, 27.3 months; range, 12-63). Surgical strategy was also analyzed.

RESULTS

Nineteen patients (70.4%) achieved Engel's class I outcome, while 4 patients (14.8%) did not show significant improvement. Of all observed seizures, two different onset patterns of intracranial electrophysiology recorded by SEEG were observed. Patients presented with focal low-voltage fast activity were more likely to obtain seizure freedom (p = 0.045), while classification (p = 0.478), volume (p = 0.546), history of resection (p = 0.713), seizure types (p = 0.859), or seizure duration (p = 0.415) showed no significant effect on the outcome. Weight gain was the most common long-term complication (18.5%).

CONCLUSION

The SEEG can guide the ablation of HH and serve as an important factor to predict favorable seizure outcomes. Radiofrequency thermocoagulation guided by SEEG can offer a minimally invasive and low-risk surgical approach with excellent outcomes. Disconnecting the attachment of HH should be the appropriate strategy to obtain the best seizure outcome.

Epileptic hypothalamic hamartomas impact of topography on clinical presentation and radiosurgical outcome

INTRODUCTION

Evidence exists for the role of the hypothalamic hamartoma's topography as a determinant for the clinical presentation. How the hamartoma relation to the hypothalamic structures can make clinical presentations, severity and surgery outcomes different from patient to patient is largely unknown. Our aim was to analyze the effect of fine anatomical topography on clinical spectrum and radiosurgery outcome.

METHODS

Forty-eight epileptic patients with hypothalamic hamartoma were treated by Gamma Knife Surgery and were reviewed for fine topography and morphology using magnetic resonance neuroimaging. We evaluated different topographic patterns; contact to prominent structures (the mammillary body, tuber cinereum and pituitary stalk), the degree of involvement within sagittally-oriented regions, (mammillary, tuberal, and supra optic) coronally-oriented zones (periventricular, medial, and lateral), lesion dimensions (length, width, and height),and volumes (total, intra-hypothalamic, and extra-hypothalamic volumes). This data were statistically analysed for correlation with all clinical variables and epilepsy surgery outcome. We reviewed all the classification protocols in the literature.

RESULTS

Focal onset impaired awareness seizures started at an earlier age of onset with larger hypothalamic hamartoma volume and dimensions. Lateral extension within the hypothalamus was associated with more severe epilepsy, higher seizure frequency, more severe psychiatric comorbidity, hetero-aggression, hyperkinesia, and school difficulties. Presence of precocious puberty was positively correlated to anterior-posterior extension; tuberal region involvement, hypothalamic hamartoma volume, and type III-VI. Larger hypothalamic hamartoma presented precocious puberty at an earlier age of onset. After Gamma Knife Surgery, epilepsy outcome was better and rapid when lesion is smaller. Post-radiosurgical transient increased seizures were present when the mammillary region was more involved.

CONCLUSION

Clinical presentation of epileptic hypothalamic hamartoma is significantly affected by fine topography patterns and invaded hypothalamic areas. Gamma Knife Radiosurgery effect is better and rapid in smaller hamartoma (Type I-III) and seizure outcome was not affected by the invaded hypothalamic areas.

Epileptic Spasms in a Large Hypothalamic Hamartoma Cohort

INTRODUCTION

Hypothalamic hamartoma is rarely associated with epileptic spasms. We describe epileptic spasms in a large cohort of hypothalamic hamartoma patients.

METHODS

We performed a retrospective chart review between March 2011 and March 2020 to identify patients with hypothalamic hamartoma and epilepsy.

RESULTS

We identified 114 patients with hypothalamic hamartoma and epilepsy, only 3 male patients (2.6%) also had epileptic spasms. The epileptic spasms developed between 6 and 18 months of age. Epileptic spasms resolved with oral prednisolone in 1 and with vigabatrin in the second patient. The third patient continued epileptic spasms despite multiple antiepileptic drugs and partial resection of hypothalamic hamartoma. All 3 patients underwent laser-ablation of hypothalamic hamartoma at the age of 14, 29, and 63 months. The seizure burden decreased by 100%, 84%, and 93% at follow-up (3-47 months).

CONCLUSIONS

Epileptic spasms are rare in hypothalamic hamartoma patients and early laser-ablation could potentially treat epileptic spasms and all other seizure types associated with hypothalamic hamartoma.

Glucose Metabolism Characteristics of Extra-Hypothalamic Cortex in Patients With Hypothalamic Hamartomas (HH) Undergoing Epilepsy Evaluation: A Retrospective Study of 16 Cases

Purpose: There are few studies on the glucose metabolic characteristics of the extra-hypothalamic cortex in the hypothalamic hamartomas (HH). A comprehensive understanding of pathogenic progression of the disease is required from the perspective of cortical metabolism; therefore, we aimed to characterize metabolic characteristics of extra-hypothalamic in HH patients.

Methods: We investigated the metabolic characteristics of 16 HH patients, all of whom underwent epilepsy evaluation at Xuan Wu Hospital between 2017 and 2019. The lateralization and cortical distribution pattern of hypometabolism was assessed and related to HH mass neuroanatomy on magnetic resonance imaging (MRI) as well as scalp-electroencephalogram (scalp-EEG) abnormalities. Furthermore, asymmetry measurements of region of interest (ROI) in the temporal cortex (hippocampal formation, amygdala, and lateral temporal neocortex) were quantitatively assessed based on the normalized average positron emission tomography (PET) voxel values. The surgery prognosis was assessed using the International League Against Epilepsy (ILAE) classification system.

Results: The lateralization of hypometabolism in global visual ratings was consistent with the HH mass lateralization seen on MRI. Cortical hypometabolism showed three patterns depending whether the HH mass involved mammillary bodies, middle hypothalamus nucleus, or both. The three patterns were hypometabolism of the mesial temporal cortex with symptom of mesial temporal epilepsy (3/16, pattern I), lateral temporal, and extratemporal (frontal or parietal) cortex with symptom of neocortex temporal or frontal epilepsy (5/16, pattern II), and mesial and lateral temporal cortex and extratemporal (frontal or parietal) cortex with varied symptoms (8/16, pattern III), respectively. A significant difference in PET voxel values was found between bilateral hippocampal formation (P = 0.001) and lateral temporal neocortex in the third group (P = 0.005). We suggest that the hypometabolic characteristics of the extra-hypothalamic cortex in HH patients have three patterns. The final cortical hypometabolic pattern depends on the neuroanatomic location of the HH mass and was consistent with the main involved cortex of the interictal and ictal discharges. The third hypometabolic pattern with the most extensive cortical hypometabolism has a poorer prognosis.

Gelastic seizures and the hypothalamic hamartoma syndrome: Epileptogenesis beyond the lesion?

The clinicoradiologic syndrome of hypothalamic hamartoma (HH) manifests with a variety of symptoms, including pharmacoresistant epilepsy with multiple seizure types, precocious puberty, behavioral disturbances, and cognitive impairment. Gelastic seizures are an early marker of epilepsy with HH in most of the cases. Despite a high variability, two major epilepsy phenotypes can be distinguished, based on electroclinical features: (i) focal seizures with epigastric or déjà-vu aura, loss of consciousness, and oroalimentary or gestural automatisms suggestive of temporal lobe involvement; and (ii) motor seizures with tonic, atonic, myoclonic, or versive phenomena, suggesting frontoparietal network involvement, with possible evolution toward an epileptic encephalopathy. The underlying physiopathologic mechanisms are not completely elucidated. The well-known intrinsic epileptogenicity of the HH represents the rationale for direct HH-aiming surgical procedures, with variable success in achieving seizure freedom. The concept of kindling-like secondary epileptogenesis has been suggested as a possible putative mechanism since the very beginnings of the hamartocentric era. Accordingly, a cortical area with enhanced epileptogenic properties due to an independent stage of secondary epileptogenesis would be responsible for seizures persisting after hamartoma ablation. However, recent intracerebral stereotactic EEG (SEEG) explorations demonstrated more complex, both reciprocal and hierarchical, relationships within the hypothalamo-cortical epileptogenic networks. Network formation may be due to either secondary epileptogenesis or widespread epileptogenicity present at the outset. A short time window from epilepsy onset to surgery seems to be crucial to cure epilepsy by direct surgery addressing a hamartoma. SEEG exploration may be reasonably proposed in cases where clinical data suggest an extension of the epileptogenic zone outside the limits of the HH, especially in focal seizures with impaired awareness and absence of gelastic seizures, or after a failure of the direct HH-aiming procedure.

Surgical treatment of hypothalamic hamartomas

Hypothalamic hamartomas are aberrant masses, composed of abnormally distributed neurons and glia. Along endocrine and cognitive symptoms, they may cause epileptic seizures, including the specific gelastic and dacrystic seizures. Surgery is the treatment of drug-resistant hamartoma epilepsy, with associated positive results on endocrine, psychiatric, and cognitive symptoms. Recently, alternatives to open microsurgical treatment have been proposed. We review these techniques and compare their efficacy and safety. Open resection or disconnection of the hamartoma, either through pterional, transcallosal, or transventricular approach, leads to good epileptological control, but its high complication rate, up to 30%, limits its indications. The purely cisternal peduncular forms remain the only indication of open, pterional approach, while other strategies have been developed to overcome the neurological, endocrine, behavioral, or cognitive complications. Laser and radiofrequency thermocoagulation-based disconnection through robot-guided stereo-endoscopy has been proposed as an alternative to open microsurgical resection and stereotactic destruction. The goal is to allow safe and complete disconnection of a possibly complex attachment zone, through a single intraparenchymal trajectory which allows multiple laser or radiofrequency probe trajectory inside the ventricle. The efficacy was high, with 78% of favorable outcome, and the overall complication rate was 8%. It was especially effective in patients with isolated gelastic seizures and pure intraventricular hamartomas. Stereotactic radiosurgery has proved as efficacious and safer than open microsurgery, with around 60% of seizure control and a very low complication rate. Multiple stereotactic thermocoagulation showed very interesting results with 71% of seizure freedom and 2% of permanent complications. Stereotactic laser interstitial thermotherapy (LiTT) seems as effective as open microsurgery (from 76 to 81% of seizure freedom) but causes up to 20% of permanent complications. This technique has however been highly improved by targeting only the epileptogenic onset zone in the hamartoma, as shown on preoperative functional MRI, leading to an improvement of epilepsy control by 45% (92% of seizure freedom) with no postoperative morbidity. All these results suggest that the impact of the surgical procedure does not depend on purely technical matters (laser vs radiofrequency thermocoagulation or stereotactic vs robot-guided stereo-endoscopy) but relies on the understanding of the epileptic network, including inside the hamartoma, the aim being to plan an effective disconnection or lesion of the epileptogenic part while sparing the adjacent functional structures.

Electrophysiological properties and seizure networks in hypothalamic hamartoma

Objective

Little is known about the intrinsic electrophysiological properties of hypothalamic hamartoma (HH) in vivo and seizure network since only few cases using stereoelectroencephalography (SEEG) electrodes exploring both cortex and HH have been published. To elucidate these issues, we analyzed simultaneous SEEG recordings in HH and cortex systematically.

Methods

We retrospectively investigated data from 15 consecutive patients with SEEG electrodes into the HH for the treatment purpose of radiofrequency thermocoagulation treatment. Additional SEEG electrodes were placed into the cortex in 11 patients to assess extra‐HH involvement. Interictal discharges within the HH and anatomo‐electroclinical correlations during seizures of each patient were qualitatively and quantitatively analyzed.

Results

Overall, 77 electrodes with 719 contacts were implanted, and 33 spontaneous seizures were recorded during long‐term SEEG monitoring. Interictally, distinct electrophysiological patterns, including isolated intermittent spikes/sharp waves, burst spike and wave trains, paroxysmal fast discharges, periodic discharges, and high‐frequency oscillations, were identified within the HH. Notably, synchronized or independent interictal discharges in the cortex were observed. Regarding the ictal discharges, the electrical onset pattern within the HH always started with abrupt giant shifts superimposed on low‐voltage fast activity across patients. The gelastic seizure network mainly involved the HH, orbitofrontal areas, and cingulate gyrus. Seizures with automatisms and impaired awareness primarily propagated to mesial temporal lobes. Moreover, independent ictal discharges arising from the mesial temporal lobe were detected in three out of nine patients.

Interpretation

This study comprehensively reveals intrinsic electrophysiological patterns and epileptogenic networks in vivo, providing new insights into the mechanisms underlying cortical and subcortical epileptogenesis.

Optimized stereoelectroencephalography-guided radiofrequency thermocoagulation in the treatment of patients with focal epilepsy

Epilepsy is a severe health disorder affecting people of all ages with high prevalence worldwide. The introduction of new antiepileptic drugs has yielded notable effects in recent decades, yet there are still approximately 30% of patients with seizures refractory to medical therapy. Open surgical resection is widely accepted as a highly effective approach for the treatment of drug-resistant focal epilepsy if the epileptogenic zone can be precisely delineated. However, concerns about the impact of open surgery on brain function have driven considerable interest in less invasive techniques. Clinically, stereoelectroencephalography (SEEG) offers a unique means of exploring the pathophysiologic process and accurately mapping the epileptogenic network in presurgical evaluations for patients with epilepsy because of insufficient information from other noninvasive investigations. Moreover, SEEG-guided radiofrequency thermocoagulation (SEEG-guided RF-TC), which ablates lesions directly through the recording electrodes according to electroclinical evidence, has emerged as a promising, minimally invasive modality with notable preservation of neurocognitive functions. This critical review summarizes the technical details of the parameters and the selection of patients for SEEG-guided RF-TC based on the literature as well as our experiences. With respect to the parameters, the power and duration of RF-TC are discussed. In particular, an optimized SEEG-guided RF-TC modality that integrates more contacts from multiple different electrodes to create a confluent lesioning field is proposed for a more curative effect in comparison to the current protocol of palliative treatment in which RF-TC selectively disrupts critical hubs in the epileptic network through contiguous contacts within the range of a single electrode. Currently, SEEG-guided RF-TC is indicated for a variety of small, deeply seeded and well-demarcated epileptogenic foci, such as deep heterotopic nodules and hypothalamic hamartoma. The efficacy of treating patients with focal cortical dysplasias in the eloquent cortex and with mesial temporal lobe epilepsy associated with hippocampal sclerosis needs to be further determined. Given the small number of patients reported, randomized controlled trials are necessary to compare the efficacy of SEEG-guided RF-TC with conventional methods in the future.

Hypothalamic hamartomas in adulthood: Clinical spectrum and treatment outcome-A unicenter experience

INTRODUCTION

Clinical manifestations of the hypothalamic hamartoma-epilepsy syndrome (HH-ES) in adulthood are variable. Efficacy of therapeutic options and outcome are diverse.

METHODS

Retrospective study of adult patients diagnosed with a HH in magnetic resonance imaging and epilepsy who attended our tertiary Epilepsy Unit between 2003 and 2018. We report the clinical and electroencephalographic features of a series of adult patients with HH and related epilepsy seen in our center together with the treatments and seizure outcome.

RESULTS

We describe a series of eight patients. Five males (62.5%), median age at evaluation was 28.5 years (IQR: 15.5). Clinical manifestations included focal with preserved and impaired awareness emotional seizures (gelastic seizures [GS]) in six patients (75%), focal tonic, atonic with impaired awareness and focal to bilateral tonic-clonic seizures. Mild GS were the only symptom in one patient. Three patients (37.5%) had endocrinological disturbances such as obesity and hypothyroidism. Fifty percent of the patients showed psychiatric comorbidity such as anxiety disorder and aggressiveness, and two patients had psychomotor delay. Seven patients (87.7%) had drug-resistant seizures and three of them were treated with radiosurgery. Out of the treated group, only one (33.3%) became seizure-free 2 years after surgery but developed psychiatric problems. The other two patients had an Engel IV outcome and received a vagal nerve stimulation (VNS) implant. VNS did not lead to changes either in intensity nor in seizure frequency.

CONCLUSIONS

Hypothalamic hamartoma-epilepsy syndrome clinical manifestations in adult patients are as variable as at pediatric age. Outcome of therapeutic options such as radiosurgery or VNS may be poorer at this stage.

Episodes of prolonged "trance-like state" in an infant with hypothalamic hamartoma

Hypothalamic hamartoma (HH) is one of the most common causes of central precocious puberty (CPP) in first few years of life. It can present with either seizures or CPP, although both manifestations coexist in the majority of the children. Gelastic seizures (GS), or laughing spells, are usually the first type of seizures seen in patients with HH. Although a wide variety of seizure types are known to occur in children with HH, GS are most common and consistent seizure type. The clinical presentation of HH may vary with the size and position of the mass, although large tumours typically present with both CPP and seizures. Although CPP can be managed with medical therapy, seizures can be very difficult to treat, even with multiple antiepileptic drugs. Noninvasive gamma knife surgery has been used with some success for the treatment of refractory epilepsy. We present a case of HH with very early onset seizures and CPP. The patient had an atypical form of seizures described by the parents as a "trance-like state" in which the patient had prolonged episodes of unresponsiveness lasting for hours with normal feedings during the episodes. GS occurred late in the course and were refractory to various combinations of antiepileptic drugs. A brain magnetic resonance imaging showed a large sessile HH (>20 mm). Later in the course of the disease, the patient experienced cognitive and behavioural problems. The patient underwent gamma knife surgery at nearly 5 years of age and experienced a modest response in seizure frequency. This case highlights the presentation of HH as a previously unreported seizure morphology described as a prolonged "trance-like state.".

Brief Behavioral Intervention for Disruptive Behavior in a Child with a Hypothalamic Hamartoma: A Case Report

Most children with hypothalamic hamartoma (HH) manifest symptoms of epilepsy and associated cognitive deficits and behavioral difficulties as well as central precocious puberty (CPP). However, there is little to no research examining behavioral difficulties in children with HH without epilepsy, nor is there research examining treatments to address the behavioral difficulties of patients with HH without epilepsy. In the current case report, the authors implemented a validated parent management training program [the Brief Behavioral Intervention (BBI)], to treat symptoms of ADHD and disruptive behavior in a 6-year-old female patient with HH and CPP. The family participated in six BBI sessions over a period of 8 weeks. Parent behavioral ratings suggested significant reductions of symptoms of ADHD and disruptive behaviors to the normal range. The current case report demonstrates the effectiveness of the BBI program in the treatment of behavioral difficulties in a patient with HH and CPP. Further, the present study explores behavioral manifestations rarely explored in patients with HH without epilepsy.

A case of pure gelastic seizures due to hypothalamic hamartoma with a benign course

Hypothalamic hamartoma is a potentially complex entity with diverse clinical manifestations. We report a case of gelastic seizures associated with a hypothalamic hamartoma, which followed a benign course. A 31-year-old woman with episodes of laughter was referred for diagnostic evaluation. Her initial MRI and EEG were reported as normal. However, her episodes of laughter were typical of gelastic seizures from history and video review. Repeat MRI revealed a small HH. She declined any medical treatment and was medication free until last follow-up. This benign course of HH-associated epilepsy, not necessitating treatment, to our knowledge, has not been previously reported.

Pure endoscopic management of epileptogenic hypothalamic hamartomas

Hypothalamic hamartomas (HH) are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Their usual clinical presentation is characterized by gelastic/dacrystic seizures which often become pharmaco-resistant and progress to secondary focal/generalized intractable epilepsy causing mostly in children cognitive and behavioral problems (particularly in cases of progressive epileptic encephalopathy) and precocious puberty. Whereas gelastic seizures can be surgically controlled either by resection of the lesion or disconnection (tissue-destructive) procedures, aimed at functionally prevent the spreading of the epileptic burst; generalized seizures tend to respond better to HH excision rather than isolated neocortical resections, which generally fail to control them. Prospective analysis of 14 consecutive patients harboring HH treated in an 8-year period; 12 patients had unilateral and two bilateral HH. All patients were managed by pure endoscopic excision of the HH. The mean operative time was 48 min and mean hospital stay was 2 days; perioperative blood loss was negligible in all cases. Two patients showed a transient diabetes insipidus (DI); no transient or permanent postoperative neurological deficit or memory impairment was recorded. Complete HH excision was achieved in 10/14 patients. At a mean follow-up of 48 months, no wound infection, meningitis, postoperative hydrocephalus, and/or mortality were recorded in this series of patients. Eight patients became seizure free (Engel class I), 2 other experienced worthwhile improvement of disabling seizures (Engel class II); 2 patients were cured from gelastic attacks while still experiencing focal dyscognitive seizures; and 2, having bilateral HH (both undergoing unilateral HH excision), did not experience significant improvement and required later on a temporal lobectomy coupled to amygdalohyppocampectomy. Overall, the followings resulted to be predictive factors for better outcomes in terms of seizure control: (1) cases of unilateral, Delalande class B, HH, (2) shorter history of epilepsy. Endoscopic resection of HH proved, in our series, to be effective in achieving complete control or in reducing the frequency of seizures. Furthermore, this approach has confirmed its minimally invasive nature with a very low morbidity rate: of note, it allowed to better preserve short-term memory and hypothalamic function.

Epileptic network of hypothalamic hamartoma: An EEG-fMRI study

OBJECTIVE

To investigate the brain networks involved in epileptogenesis/encephalopathy associated with hypothalamic hamartoma (HH) by EEG with functional MRI (EEG-fMRI), and evaluate its efficacy in locating the HH interface in comparison with subtraction ictal SPECT coregistered to MRI (SISCOM).

METHODS

Eight HH patients underwent EEG-fMRI. All had gelastic seizures (GS) and 7 developed other seizure types. Using a general linear model, spike-related activation/deactivation was analyzed individually by applying a hemodynamic response function before, at, and after spike onset (time-shift model=-8-+4s). Group analysis was also performed. The sensitivity of EEG-fMRI in identifying the HH interface was compared with SISCOM in HH patients having unilateral hypothalamic attachment.

RESULTS

EEG-fMRI revealed activation and/or deactivation in subcortical structures and neocortices in all patients. 6/8 patients showed activation in or around the hypothalamus with the HH interface with time-shift model before spike onset. Group analysis showed common activation in the ipsilateral hypothalamus, brainstem tegmentum, and contralateral cerebellum. Deactivation occurred in the default mode network (DMN) and bilateral hippocampi. Among 5 patients with unilateral hypothalamic attachment, activation in or around the ipsilateral hypothalamus was seen in 3 using EEG-fMRI, whereas hyperperfusion was seen in 1 by SISCOM.

SIGNIFICANCE

Group analysis of this preliminary study may suggest that the commonly activated subcortical network is related to generation of GS and that frequent spikes lead to deactivation of the DMN and hippocampi, and eventually to a form of epileptic encephalopathy. Inter-individual variance in neocortex activation explains various seizure types among patients. EEG-fMRI enhances sensitivity in detecting the HH interface compared with SISCOM.

Clinical characteristics and long-term outcome of surgery for hypothalamic hamartoma in children with refractory epilepsy

CONTEXT

Hypothalamic hamartomas (HH) are ectopic masses of neuronal and glial tissue most commonly presenting with medically refractory gelastic seizures with evolution to other seizure types. They are also associated with cognitive and behavioral problems to varying extent. Surgery has been found to improve quality of life in more than 50% of patients.

AIM

To evaluate the clinical characteristics and long-term outcome of surgery in children with HH and refractory epilepsy.

MATERIALS AND METHODS

A retrospective analysis of presurgical, surgical, and postsurgical data of six children who underwent surgery for HH and had at least 3 years follow-up was performed.

RESULTS

SIX CHILDREN (MALE: female = 5:1) aged 3-16 years (at the time of surgery) underwent surgical resection of HH for refractory epilepsy. At last follow-up (range 3-9 years), three children were in Engel's class I, two in Class II, and one in class III outcome. Significant improvement in behavior, quality of life was noted in four children; while the change in intelligence quotient (IQ) was marginal.

CONCLUSIONS

Medically refractory epilepsy associated with behavioral and cognitive dysfunction is the most common presentation of HH. Open surgical resection is safe with favorable outcome of epilepsy in 50% with significant improvement in behavior and marginal change in cognitive functions.

Hypothalamic hamartomas. Part 1. Clinical, neuroimaging, and neurophysiological characteristics

Hypothalamic hamartomas are uncommon but well-recognized developmental malformations that are classically associated with gelastic seizures and other refractory seizure types. The clinical course is often progressive and, in addition to the catastrophic epileptic syndrome, patients commonly exhibit debilitating cognitive, behavioral, and psychiatric disturbances. Over the past decade, investigators have gained considerable knowledge into the pathobiological and neurophysiological properties of these rare lesions. In this review, the authors examine the causes and molecular biology of hypothalamic hamartomas as well as the principal clinical features, neuroimaging findings, and electrophysiological characteristics. The diverse surgical modalities and strategies used to manage these difficult lesions are outlined in the second article of this 2-part review.

The gelastic seizures-hypothalamic hamartoma syndrome: facts, hypotheses, and perspectives

Hypothalamic hamartoma (HH) can be associated with a wide spectrum of epileptic conditions, ranging from a mild form with seizures characterized by urge to laugh and no cognitive involvement up to a catastrophic encephalopathy with early onset gelastic seizures (GS), precocious puberty, and mental retardation. Moreover, a refractory, either focal or generalized, epilepsy develops during the clinical course in nearly all the cases. Neurophysiologic and neuroimaging studies have demonstrated that HH itself generates GS and starts a process of secondary epileptogenesis responsible for refractory focal or generalized epilepsy. The intrinsic epileptogenicity of HH may be explained by the neurophysiological properties of small GABAergic, spontaneously firing HH neurons. Surgical ablation of HH can reverse epilepsy and encephalopathy. Gamma-knife radiosurgery and image-guided robotic radiosurgery seem to be useful and safe approaches for treatment, in particular of small HH. Here, we review this topic, based on literature reports and our personal observations. In addition, we discuss pathogenetic hypotheses and suggest new approaches to this intriguing issue.

Transendoscopic intraoperative recording of gelastic seizures from a hypothalamic hamartoma

OBJECT

The differential diagnosis of hypothalamic masses in children includes hamartomas, which are associated with gelastic seizures and endocrine dysfunction. The purpose of this study was to utilize transendoscopic electroencephalography (EEG) recording at the time of tissue biopsy to further assist in diagnosis, determination of prognosis, and treatment planning.

METHODS

We present the case of an infant with gelastic seizures and a large hypothalamic mass lesion. Despite a clinical and radiographic presentation typical of hypothalamic hamartoma (HH), slight growth on serial imaging raised concern for a diagnosis of intrinsic neoplasm. Biopsy of the lesion was recommended.

RESULTS

Transventricular, endoscopic biopsy, was undertaken, with concurrent intraoperative, transendoscopic EEG recording using a standard epilepsy depth recording macroelectrode. Numerous electrographic seizures were recorded. Histopathology revealed a HH.

CONCLUSION

This is the first report of intraoperative macroelectrode recording of electrographic seizures transendoscopically from a HH. This technique may prove useful for diagnosis, prognosis and treatment planning, as well as to guide transendoscopic therapeutic interventions for HH.

Two cases of precocious puberty associated with hypothalamic hamartoma

Hypothalamic hamartoma (HH) is a congenital malformation diagnosed based on magnetic resonance imaging (MRI) and histological findings; it is often associated with central precocious puberty (CPP), gelastic seizures, abnormal behavior and mental retardation. In the present paper, we report our retrospective hypothesis that there is a relationship between symptoms and therapy, as well as the treatment for HH, and describe two cases of HH associated with CPP. Both cases had sessile masses located in the interpeduncular cistern, with extension to the hypothalamus on MRI (1.2 × 1.5 cm and 2.0 × 2.5 cm, respectively). The first case had intractable seizures, while the second had no seizures with paroxysmal discharge. In both patients, the hamartomas were partially removed, by γ-knife and surgical operation in the first case and surgically in the second, and a gonadotropin releasing hormone (GnRH) analogue was prescribed. One case showed improvement of both intelligence quotient (IQ) score and seizures, and the other showed improvements in IQ and abnormal behavior. It was difficult to determine any topology/symptom relationships. Surgery and GnRH analogue treatment can alleviate seizures, abnormal behavior and mental retardation associated with HH.

Minimally invasive magnetic resonance imaging-guided stereotactic radiofrequency thermocoagulation for epileptogenic hypothalamic hamartomas

OBJECTIVE

To validate the safety and efficacy of magnetic resonance imaging (MRI)-guided stereotactic radiofrequency thermocoagulation (SRT) for epileptogenic hypothalamic hamartoma (HH), we evaluated surgical outcomes and revised the MRI classification.

METHODS

We retrospectively reviewed 25 consecutive patients with HH (age range, 2-36 years; mean age, 14.8 years) with gelastic seizures. Other seizure types were exhibited in 22 patients (88.0%), precocious puberty in 8 (32.0%), behavioral disorder in 10 (40.0%), and mental retardation in 14 (56.0%). We classified HH into 3 subtypes according to coronal MRI: intrahypothalamic, parahypothalamic, and mixed hypothalamic type. Maximum diameter ranged from 8 to 30 mm (mean, 15.3 mm). All patients underwent SRT (74 degrees C, 60 seconds) for HH.

RESULTS

HH subtype and size were correlated with precocious puberty, mental retardation, and behavioral disorder. Thirty-one SRT procedures were performed, requiring 1 to 8 tracks (mean, 3.8 tracks) and involving 1 to 18 lesions (mean, 7.2 lesions). There were no adaptive limitations, regardless of size or subtype. Mixed-type HHs needed more tracks and more lesions. No permanent complications persisted after SRT, and gelastic seizures disappeared in all but 2 patients. Complete seizure freedom was achieved in 19 patients (76.0%). These patients had not only disappearance of all seizure types and behavioral disorder but also intellectual improvement.

CONCLUSION

The present SRT procedure has favorable efficacy and invasiveness and has no adaptive limitations. SRT should therefore be considered before adulthood. The new HH classification is useful to understand clinical symptoms and to determine surgical strategies.

Surgical management of hypothalamic hamartomas in patients with gelastic epilepsy

Gelastic epilepsy (GE) associated with hypothalamic hamartomas (HHs) is now a well-characterized clinical syndrome consisting of gelastic seizures starting in infancy, medically refractory seizures with or without the development of multiple seizure types, and behavioral and cognitive decline. It has been postulated that the development of the HH-GE syndrome is a result of a progressive epileptic encephalopathy or secondary epileptogenesis, which is potentially reversible with treatment of the HH. A variety of surgical options for the treatment of HHs exist, including open and endoscopic procedures, radiosurgery, interstitial radiotherapy, and stereotactic radiofrequency thermocoagulation. Surgical treatment can result in seizure freedom in up to 50% of patients and can be accompanied by significant improvements in behavior, cognition, and quality of life. Partial treatment of HHs may be sufficient to reduce seizure frequency and improve behavior and quality of life with less risk. A component of reversible cognitive dysfunction may be present in some patients with an HH-GE syndrome.

A review on the management of epilepsy associated with hypothalamic hamartomas

INTRODUCTION

Hypothalamic hamartomas are rare congenital malformations located in the region of the tuber cinereum and third ventricle. Patients may be asymptomatic, but the usual presentation is gelastic seizures, precocious puberty, and/or developmental delay.

CLINICAL PRESENTATION

Without surgical intervention, the gelastic seizures, which are typically present in childhood, may progress to other seizure types, including generalized epilepsy, and are generally refractory to antiepileptic drugs.

SUMMARY

This review will discuss the clinical and electrophysiologic aspects of these lesions, as well as treatment options, including surgery, endoscopy, and radiosurgery.

Gelastic seizures associated with hypothalamic hamartomas. An update in the clinical presentation, diagnosis and treatment

Gelastic seizures are epileptic events characterized by bouts of laughter. Laughter-like vocalization is usually combined with facial contraction in the form of a smile. Autonomic features such as flushing, tachycardia, and altered respiration are widely recognized. Conscious state may not be impaired, although this is often difficult to asses particularly in young children. Gelastic seizures have been associated classically to hypothalamic hamartomas, although different extrahypothalamic localizations have been described. Hypothalamic hamartomas are rare congenital lesions presenting with the classic triad of gelastic epilepsy, precocious puberty and developmental delay. The clinical course of patients with gelastic seizures associated with hypothalamic hamartomas is progressive, commencing with gelastic seizures in infancy, deteriorating into more complex seizure disorder resulting in intractable epilepsy. Electrophysiological, radiological, and pathophysiological studies have confirmed the intrinsic epileptogenicity of the hypothalamic hamartoma. Currently the most effective surgical approach is the trancallosal anterior interforniceal approach, however newer approaches including the endoscopic and other treatment such as radiosurgery and gamma knife have been used with success. This review focuses on the syndrome of gelastic seizures associated with hypothalamic hamartomas, but it also reviews other concepts such as status gelasticus and some aspects of gelastic seizures in other locations.