Cerebral Hemispheric Lateralization Associated with Hippocampal Sclerosis May Affect Interictal Cardiovascular Autonomic Functions in Temporal Lobe Epilepsy

Abstract

It is well established that the temporal lobe epilepsy (TLE) is linked to the autonomic nervous system dysfunctions. Seizures alter the function of different systems such as the respiratory, cardiovascular, gastrointestinal, and urogenital systems. The aim of this work was to evaluate the possible factors which may be involved in interictal cardiovascular autonomic function in temporal lobe epilepsy with complex partial seizures, and with particular attention to hippocampal sclerosis. The study was conducted in 30 patients with intractable temporal lobe epilepsy (19 with left hippocampal sclerosis, 11 with right hippocampal sclerosis). All subjects underwent four tests of cardiac autonomic function: heart rate changes in response to deep breathing, heart rate, and blood pressure variations throughout resting activity and during hand grip, mental stress, and orthostatic tests. Our results show that the right cerebral hemisphere predominantly modulates sympathetic activity, while the left cerebral hemisphere mainly modulates parasympathetic activity, which mediated tachycardia and excessive bradycardia counterregulation, both of which might be involved as a mechanism of sudden unexpected death in epilepsy patients (SUDEP).

Respuesta cardiovascular al estrés en pacientes con epilepsia farmacorresistente: datos preliminares

“…Contrary to our results, previous studies have found hemispheric specialisation for these cardiovascular parameters, RH activation being related to prominent tachycardia (Xavier et al, 2009) and RH anesthesia being related to HR increases and LF/HF ratio and HF decreases (Ahern et al, 2001). Moreover, other studies have found highly elevated parasympathetic activity in the left TLE with hippocampal sclerosis compared to right TLE with hippocampal sclerosis (Ghchime et al, 2016). All studies mentioned above empathising a RH lateralisation of sympathetic cardiac control and LH lateralisation of parasympathetic control (Behbahani et al, 2016;Oppenheimer, 2006;Saleh et al, 2000;Xavier et al, 2009).…”

Sympatholysis subsequent to intraoperative amygdalohippocampal stimulation: A report of three pediatric neurosurgical cases with literature review

“…observed that the right cerebral hemisphere predominantly modulates sympathetic activity while the left cerebral hemisphere mainly modulates parasympathetic activity. [8] Their results are somewhat consistent with other previous investigations. [910] These findings also accentuate our observations of predominant sympatholytic activity on stimulation of left amygdala and/or hippocampus.…”

Comparison of Autonomic Function before and after Surgical Intervention in Patients with Temporal Lobe Epilepsy

“…Consistent with our present findings, a previous study 35 examining patients with hippocampal sclerosis associated with TLE found that before surgery, patients with hippocampal sclerosis and LTLE had elevated parasympathetic response, while those with RTLE had elevated sympathetic response, which mediated excessive bradycardia and tachycardia counter-regulation. To understand the mechanism of autonomic modulation in patients with LTLE and RTLE, we included 2 time points after surgery and found that surgical removal of the affected lesion or area influenced autonomic CV modulation differentially.…”