Insula- The Lesse Known Fifth Lobe

Presented by Navita Kaushal PhD, REEGT, RNCST, CLTM

Embedded deep beneath the sylvian/lateral fissure, pyramidal shaped covering less than 2% of the cortex, with dense blood supply from MCA, separated yet so connected with frontal, temporal, parietal, and limbic areas, is the least understood 5th lobe of the brain-Insula. It was discovered in 1809 but was not well understood or greatly explored till the early 1950s.
The insular cortex has direct connection with association cortical areas, autonomic nervous system, thalamus, amygdala and is involved in wide range of functions from pain perception, speech, smell, taste, social-emotion processing, cognition, and the sense of the physiological condition of the body.
Insular epilepsy is uncommon and not well recognized for two reasons. One, because of its location the scalp electrodes cannot record seizures from the insula. Two, due to its extensive connectivity, seizures originating in the insula mimics seizures originating from other areas of the brain. The seizures present as if the epileptic zone is in the temporal or the frontal lobe. The clinical signs of the insular seizures are objective as well as subjective including visceral and somatic sensations, olfactory, gustatory, and auditory auras, autonomic symptoms, aphasia, epileptic spasms and tonic-clonic or clonic movements.

In this webinar functions of insula, seizure semiology of insular epilepsies and a few case studies from the literature are discussed.