Features of somatosensory manifestations induced by intracranial electrical stimulations of the human insula

ObjectiveTo study the clinical manifestations induced by intracranial electrical stimulation of the insular cortex in epileptic patients submitted to invasive stereo-electroencephalography (SEEG) recordings.MethodsWe retrospectively studied the clinical manifestations induced by intracerebral electrical stimulations of the insular cortex in 96 patients. In order to precisely localize the position of the electrodes a postoperative 3D CT scan or a 3D MRI was obtained and then the images were merged with the preoperative MRI in the same stereotactic referenced system.ResultsA total of 341 electrical bipolar stimulations were performed. The most frequently induced symptom was a somatosensory manifestation (70%), mainly tingling and electric sensation involving the contralateral face and arm. Motor responses represented the 8% of the total amount, as well as auditory phenomena. Language dysfunction accounted for 2% of responses. Autonomic and gustatory phenomena represented respectively 1% of responses.ConclusionsWe found a great prevalence of somatosensory manifestations whereas other types of clinical modifications were extremely infrequent.SignificanceOur data support a prominent somatosensory role of the human insular cortex and provide a precise characterization of the different types of sensory manifestations induced by intracranial electrical stimulation of the human insula.

► The human insular lobe is still mostly unknown and its functions are not fully understood. ► In this study we performed 341 intracranial electrical stimulation of the insular cortex in 96 epileptic patients submitted to invasive stereo-electroencephalography recordings. ► We found a 70% of somatosensory responses, further divided into different sub-types, suggesting a key role of the insular lobe in somatosensory pathways.