Comparing Ictal Cardiac Autonomic Changes in Patients with Frontal Lobe Epilepsy and Temporal Lobe Epilepsy by Ultra-Short-Term Heart Rate Variability Analysis

Abstract

Background and Objectives: Abnormal epileptic discharges in the brain can affect the central brain regions that regulate autonomic activity and produce cardiac symptoms, either at onset or during propagation of a seizure. These autonomic alterations are related to cardiorespiratory disturbances, such as sudden unexpected death in epilepsy. This study aims to investigate the differences in cardiac autonomic function between patients with temporal lobe epilepsy (TLE) and frontal lobe epilepsy (FLE) using ultra-short-term heart rate variability (HRV) analysis around seizures. Materials and Methods: We analyzed electrocardiogram (ECG) data recorded during 309 seizures in 58 patients with epilepsy. Twelve patients with FLE and 46 patients with TLE were included in this study. We extracted the HRV parameters from the ECG signal before, during and after the ictal interval with ultra-short-term HRV analysis. We statistically compared the HRV parameters using an independent t-test in each interval to compare the differences between groups, and repeated measures analysis of variance was used to test the group differences in longitudinal changes in the HRV parameters. We performed the Tukey–Kramer multiple comparisons procedure as the post hoc test. Results: Among the HRV parameters, the mean interval between heartbeats (RRi), normalized low-frequency band power (LF) and LF/HF ratio were statistically different between the interval and epilepsy types in the t-test. Repeated measures ANOVA showed that the mean RRi and RMSSD were significantly different by epilepsy type, and the normalized LF and LF/HF ratio significantly interacted with the epilepsy type and interval. Conclusions: During the pre-ictal interval, TLE patients showed an elevation in sympathetic activity, while the FLE patients showed an apparent increase and decrease in sympathetic activity when entering and ending the ictal period, respectively. The TLE patients showed a maintained elevation of sympathetic and vagal activity in the pos-ictal interval. These differences in autonomic cardiac characteristics between FLE and TLE might be relevant to the ictal symptoms which eventually result in SUDEP.

Exploring Autonomic Alterations during Seizures in Temporal Lobe Epilepsy: Insights from a Heart-Rate Variability Analysis

“…Regarding laterality, the study found that most HRV indices included statistical differences between the right and left sides during the ictal period. These results are consistent with those of previous studies [ 48 , 54 , 74 ], which also reported lateral differences in HRV indices in patients with TLE. Both normalized low-frequency (nLF) power and the LF/HF ratio exhibited substantial increases during the ictal interval, indicating higher sympathetic activity.…”

“…The CVI during the ictal interval showed significant differences between the two groups (z = 2.20, p = 0.028), while during the postictal interval, normalized HF and the LF/HF ratio differed significantly between the two groups (z = 3.05, p = 0.002; and z = −2.7, p = 0.007, respectively). This could be related to elevated parasympathetic (vagal) activity during the postictal period [ 54 ].…”

“…They found that a 60 s interval was sufficient to approximate most HRV parameters. Other studies [ 52 , 53 , 54 ] also found that UST HRV analysis can serve as a useful surrogate method to assess HRV. The objective of this study was to assess the differences in autonomic patterns within each interval (preictal, ictal, postictal) along with the laterality and clinical factors in TLE patients using UST HRV analysis.…”

Cardiac Autonomic Dysfunction in Patients With Epilepsy

“…Autonomic dysfunction can manifest in individuals grappling with temporal lobe epilepsy or type 2 diabetes mellitus, even in the absence of neuropathy. Employing a 5-min assessment of HRV emerges as a pivotal technique for uncovering concealed cardiac autonomic neuropathy (CAN) [11,12]. The influence of seizures on the onset of cardiac autonomic neuropathy (CAN) has been implicated in instances of sudden unexpected death in epilepsy among those with the condition [5].…”