Gelastic seizures: Incidence, clinical andEEGfeatures in adult patients undergoing video‐EEGtelemetry

Abstract

SUMMARYThis study aimed to determine clinical features of adult patients with gelastic seizures recorded on video -electroencephalography (EEG) over a 5-year period. We screened video-EEG telemetry reports for the occurrence of the term "gelastic" seizures, and assessed the semiology, EEG features, and duration of those seizures. Gelastic seizures were identified in 19 (0.8%) of 2,446 admissions. The presumed epileptogenic zone was in the hypothalamus in one third of the cases, temporal lobe epilepsy was diagnosed in another third, and the remainder of the cases presenting with gelastic seizures were classified as frontal, parietal lobe epilepsy or remained undetermined or were multifocal. Gelastic seizures were embedded in a semiology, with part of the seizure showing features of automotor seizures. A small proportion of patients underwent epilepsy surgery. Outcome of epilepsy surgery was related to the underlying pathology; two patients with hippocampal sclerosis had good outcomes following temporal lobe resection and one of four patients with hypothalamic hamartomas undergoing gamma knife surgery had a good outcome. KEY WORDS: Gelastic seizures, Hypothalamic hamartoma, Temporal lobe epilepsy, Epilepsy surgery.Gelastic seizures are the hallmark of seizures arising from the hypothalamus, with hypothalamic hamartoma being the most frequent underlying pathology.1 Such seizure types are rare and are more likely to be diagnosed in childhood. Gelastic seizures in the setting of hypothalamic hamartomas are associated with childhood onset, intractable seizures, precocious puberty and, commonly, cognitive impairment. 1Functional imaging studies and intracranial electroencephalography (EEG) recordings have shown that seizures originate in the hamartomas. 2,3Recent reports have indicated that there is secondary independent epileptogenesis, 4 which is facilitated by the plethora of connections between the hypothalamus and other brain areas, particularly the temporal lobe. The hypothalamus is unlikely to be the symptomatogenic zone of gelastic seizures, as laughter and mirth involves a complex brain network involving the cingulate and basal temporal cortex. 5 This contention is supported by the fact that gelastic seizures are seen not only with hypothalamic hamartomas, but also with seizures arising from the temporal and frontal lobes.6-8 Most of these cases, with gelastic seizures arising from brain structures other than the hypothalamus, have been reported in adults. Case series of gelastic seizures in an adult cohort are lacking, and it remains to be determined whether hypothalamic hamartomas are the leading underlying pathology, and whether adults with gelastic seizures and hypothalamic hamartomas have secondary epileptogenic zones. Such information would be important, since it would prompt (1) more careful evaluation in adults with gelastic seizures and hypothalamic hamartomas and (2) would lead to a better understanding of brain areas involved in gelastic seizures. BRIEF COMMUNICATIONWe aimed to quantify the occurre...

Misdiagnoses of Epilepsy as Ekbom Syndrome, Mood Instability, and Nocturnal Visual Hallucinations

“…Gelastic seizures are mainly attributed to hypothalamic hamartomas; however it is also reported that epileptogenic zone may be in the hypothalamus as well as in the temporal lobe. In some cases, this type of seizure may be also a manifestation of epilepsy of other localizations or multifocal epilepsy [4, 5]. The phenomenology of seizures experienced by our patient (concomitant visual and auditory hallucination) suggests involvement of other regions, such as temporal lobe.…”

Surgical treatment of extra‐hypothalamic epilepsies presenting with gelastic seizures

“…Following an intracarotid amobarbital test, a successful right ATL was performed. In the largest case series of GS (Kovac et al, 2015), two out of 19 patients underwent ATL for a temporal epileptogenic zone resulting in seizure freedom. Gutierrez et al (2016) Engel Class III in one (5.6%); and Engel Class IV in two (11.1%).…”

Successful surgical management of New Onset Refractory Status Epilepticus (NORSE) presenting with gelastic seizures in a 3 year old girl

“…It is now recognized that they are not pathognomonic of HH and can be found in temporal or extratemporal, lesional or non-lesional epilepsy, mostly in adults [2], [3], [4]. However there is a growing body of evidence of such cases in children [5], [6].…”