Sensory profile alterations in patients with insular epilepsy surgery: Preliminary findings

Insula in epilepsy - "untying the gordian knot": A systematic review

PURPOSE

Despite significant advances in epileptology, there are still many uncertainties about the role of the insula in epilepsy. Until recently, most insular onset seizures were wrongly attributed to the temporal lobe. Further, there are no standardised approaches to the diagnosis and treatment of insular onset seizures. This systematic review gathers the available information about insular epilepsy and synthesizes current knowledge as a basis for future research.

METHOD

Adhering to the PRISMA guidelines, studies were meticulously extracted from the PubMed database. The empirical data pertaining to the semiology of insular seizures, insular networks in epilepsy, techniques of mapping the insula, and the surgical intricacies of non-lesional insular epilepsy were reviewed from published studies. The corpus of information available was then subjected to a process of concise summarization and astute synthesis.

RESULTS

Out of 235 studies identified for full-text review, 86 studies were included in the systematic review. The insula emerges as a brain region with a number of functional subdivisions. The semiology of insular seizures is diverse and depends on the involvement of particular subdivisions. The semiological heterogeneity of insular seizures is explained by the extensive connectivity of the insula and its subdivisions with all four lobes of the brain, deep grey matter structures, and remote brainstem areas. The mainstay of the diagnosis of seizure onset in the insula is stereoelectroencephalography (SEEG). The surgical resection of the insular epileptogenic zone (when possible) is the most effective treatment. Open surgery on the insula is challenging but magnetic resonance-guided laser interstitial thermal therapy (MRgLITT) also holds promise.

CONCLUSION

The physiological and functional roles of the insula in epilepsy have remained obfuscated. The dearth of precisely defined diagnostic and therapeutic protocols acts as an impediment to scientific advancement. This review could potentially facilitate forthcoming research endeavours by establishing a foundational framework for uniform data collection protocols, thereby enhancing the feasibility of comparing findings across future studies and promoting progress in this domain.

Psychological status after insulo-opercular resection in patients with epilepsy: Depression, anxiety, and quality of life

Insular epilepsy is increasingly recognized in epilepsy surgery centers. Recent studies suggest that resection of an epileptogenic zone that involves the insula as a treatment for drug-resistant seizures is associated with good outcomes in terms of seizure control. However, despite the existing evidence of a role of the insula in emotions and affective information processing, the long-term psychological outcome of patients undergoing these surgeries remain poorly documented. A group of 27 adults (18 women) who underwent an insulo-opercular resection (in combination with a part of the temporal lobe in 10, and of the frontal lobe in 5) as part of epilepsy surgery at our center between 2004 and 2019 completed psychometric questionnaires to assess depression (Beck Depression Inventory - 2nd edition; BDI-II), anxiety (State-Trait Anxiety Inventory, Trait Version; STAI-T), and quality of life (Patient Weighted Quality of Life In Epilepsy; QOLIE-10-P). Scores were compared to those of patients who had standard temporal lobe epilepsy (TLE) surgery with similar socio-demographic and disease characteristics. Seizure control after insular epilepsy surgery was comparable to that observed after TLE surgery, with a majority of patients reporting being seizure free (insular: 63.0%; temporal: 63.2%) or having rare disabling seizures (insular: 7.4%; temporal: 18.4%) at the time of questionnaire completion. Statistical comparisons revealed no significant group difference on scores of depression, anxiety, or quality of life. Hemisphere or extent of insular resection had no significant effect on the studied variables. In the total sample, employment status and seizure control, but not location of surgery, significantly predicted quality of life. Self-reported long-term psychological status after insulo-opercular resection as part of epilepsy surgery thus appears to be similar to that observed after TLE surgery, which is commonly performed in epilepsy surgery centers.