Takanobu Kaido1, Taisuke Otsuki, Hideyuki Nakama
1Department of Neurosurgery, National Center of Neurology and Psychiatry, Kodaira, Tokyo, Japan. kaido@ncnp.go.jp
This article reports on two patients who experienced complex seizures involving violent, hyperkinetic movements. Medical imaging and brain activity monitoring identified the source of these seizures in the insular cortex. Surgical removal of the affected brain tissue successfully stopped the seizures in both individuals. The findings suggest that clinicians should closely examine the insular region when patients present with unusual, aggressive-looking ictal behaviors.
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Area of Science:
Background:
No prior work had resolved the specific anatomical origins of complex hyperkinetic behaviors observed during certain partial seizures. That uncertainty drove clinicians to investigate whether specific brain regions might trigger these intense, violent movements. It was already known that the insular cortex plays a role in various autonomic and sensory functions. However, its involvement in generating complex, aggressive-looking ictal automatisms remained poorly defined in clinical literature. This gap motivated researchers to document cases where such behaviors were linked to insular pathology. Prior research has shown that seizures originating in the temporal lobe often manifest with diverse motor symptoms. Yet, the precise contribution of the insular cortex to these specific hyperkinetic presentations required further clarification. This study addresses that need by detailing two unique clinical cases of patients with these symptoms.
Purpose Of The Study:
This study aims to describe the clinical characteristics of complex partial seizures that manifest with violent hyperkinetic movements arising from the insular cortex. The researchers sought to document how these unusual behaviors relate to specific anatomical locations within the brain. The motivation for this work stemmed from the difficulty in diagnosing seizures that present with bizarre, aggressive-looking motor patterns. By analyzing two distinct cases, the authors intended to clarify the role of the insular region in generating these ictal automatisms. The study addresses the challenge of localizing the source of seizures when standard monitoring suggests temporal lobe involvement. The authors aimed to demonstrate that surgical resection of the insular cortex can effectively treat these complex conditions. This research provides a foundation for recognizing the specific behavioral markers associated with insular epilepsy. The primary goal was to improve diagnostic awareness among clinicians encountering patients with similar hyperkinetic seizure presentations.
The researchers propose that these seizures originate from the posterior ventral insular cortex. This mechanism involves the generation of hyperkinetic behaviors, including thrashing, rolling, and pedaling, which are distinct from typical temporal lobe seizure manifestations.
The authors utilized fluid-attenuated inversion recovery magnetic resonance imaging to detect slight high signal changes. This imaging tool was essential for identifying potential lesions in the right posterior ventral insular cortex before surgical planning.
The researchers indicate that extensive subdural electroencephalographic monitoring was necessary to confirm the seizure onset. This technical requirement allowed the team to distinguish the involvement of the lateral temporal cortices from the primary insular focus.
Main Methods:
The review approach involved a detailed analysis of two clinical cases presenting with complex partial seizures. Clinicians performed fluid-attenuated inversion recovery magnetic resonance imaging to evaluate potential structural abnormalities in the brain. The team conducted extensive subdural electroencephalographic monitoring to map the electrical activity during ictal events. Surgical teams carried out the resection of both the posterior ventral insular and lateral temporal cortices. Pathologists examined the removed tissue samples to determine the histological diagnosis for each patient. The researchers compared the clinical presentation of the 14-year-old girl and the 38-year-old woman. This methodology focused on correlating the observed hyperkinetic behaviors with the identified anatomical seizure focus. The study design prioritized the documentation of surgical outcomes following the removal of the epileptogenic lesions.
Main Results:
The strongest finding from the literature indicates that complete seizure freedom was achieved in both patients following the surgical resection of the insular cortex. Both individuals exhibited complex hyperkinetic behaviors, including rolling, thrashing, pedaling, jumping, and bizarre vocalizations. Imaging studies revealed a slight high signal change in the right posterior ventral insular cortex for both subjects. Subdural electroencephalographic monitoring confirmed that seizure onset involved the temporal lobe, necessitating the removal of both the insular and lateral temporal cortices. Histological analysis identified focal cortical dysplasia in the first patient and gliosis in the second patient. These results demonstrate that violent ictal automatism can arise from the insular region. The data suggest that these specific behavioral patterns are linked to identifiable lesions in the posterior ventral insular cortex. This evidence supports the efficacy of surgical intervention for this subset of patients with partial seizures.
Conclusions:
The authors propose that a distinct group of patients exists who experience complex partial seizures characterized by violent ictal automatism. These individuals may achieve complete seizure freedom following the surgical removal of epileptogenic lesions located within the insular cortex. The researchers suggest that careful inspection of this specific brain region is necessary to properly diagnose this seizure type. Clinical teams should consider insular pathology when evaluating patients with bizarre vocalizations or hyperkinetic movements. The study highlights the potential for successful surgical intervention in cases previously considered difficult to localize. These findings provide a framework for identifying patients who might benefit from targeted resection of the posterior ventral insular cortex. The authors emphasize that recognizing these behavioral patterns can lead to improved diagnostic accuracy and patient outcomes. Future clinical assessments should prioritize imaging and monitoring techniques that specifically target the insular region in such cases.
Histological analysis served as the primary data type for confirming the underlying pathology. The team identified focal cortical dysplasia in the younger patient and gliosis in the older patient, providing a definitive diagnosis for the resected tissue.
The patients exhibited bizarre vocalizations, jumping, and violent bimanual movements. These hyperkinetic phenomena were measured and observed during daytime seizures, distinguishing them from more common, less aggressive seizure presentations.
The authors claim that surgical resection of the insular cortex can lead to complete seizure freedom. This implication suggests that identifying these specific lesions is a viable strategy for treating patients with otherwise intractable partial seizures.