Cortical lateralization and cardiac autonomic control. Insights from insular stroke and epilepsy

Autonomic nervous system dysfunction is a common complication of stroke. Human studies and experimental data showed a hemispheric lateralization of autonomic activity concerning the forebrain and particularly the insular cortex. Insular cortex involvement is associated with more pronounced autonomic imbalance leading to life threatening arrhythmias and sudden death. We present two case reports of insular infarction in young patients without any cardiac comorbidity, illustrating a specific lateralized function of insula and its influence on the sympatho-vagal balance that implied differentiated therapeutic management after stroke. The right insular stroke was associated to sympathetic activation and left insular stroke was associated to parasympathetic predominance. The same lateralization of autonomic function with opposite effects on sympatho-vagal balance was also reported in two insular epilepsy cases, illustrating the fact that, beyond the controlling network, the cortical modulation of the autonomic nervous system is asymmetric. Identifying high risk patients prone to develop neurogenic cardiac complications, by better understanding of dysautonomia pathophysiology and consequent implementation of prophylactic and therapeutic interventions may significantly reduce mortality rate in stroke and epilepsy.