Cardiac autonomic dysfunction in drug naïve hot water epilepsy

Cortical-Subcortical morphometric signature of hot water epilepsy patients

BACKGROUND

Cortical and subcortical grey matter (GM) morphometric changes have been demonstrated Temporal Lobe Epilepsy (TLE) or Idiopathic Generalized Epilepsies (IGE). Hot Water Epilepsy (HWE) has not hitherto been studied in these perspectives.

PURPOSE

To investigate the cortical and subcortical grey matter in subjects with HWE in terms of thickness, volume, and surface area using Surface-Based Morphometry (SBM). To assess relationships of SBM-derived metrics with clinical variables.

MATERIALS AND METHODS

Ninety-nine people with HWE and 50 age-matched healthy controls underwent high resolution volumetric MRI brain. These were processed with FreeSurfer to obtain SBM parameters i:e cortical thickness, cortical volume, and Cortical surface area. Volumes of seven subcortical GM structures (hippocampus, globus pallidus, nucleus ambiguous(NA), caudate nucleus, putamen, thalamus, and amygdala) were computed. Intergroup morphometric differences and their correlation with epilepsy-specific clinical variables were calculated.

RESULTS

SBM revealed a global reduction in bihemispheric cortical thickness and left hemispheric cortical volume. Besides, a regional difference in the morphometric measures was noted in temporo-limbic, parietal, pre-cuneus, and the cingulate region. Reduced volume of thalami and left caudate alongside an increased volume of the bilateral amygdala, bilateral nucleus ambiguous (NA), right caudate, and putamen was the other cardinal observation.

CONCLUSION

HWE subjects show alterations in the morphometry of the cortical ribbon and the subcortical grey matter. The temporal semiology, 'reflex nature' pathophysiology correlates involvement of temporo-limbic structures/somatosensory cortex, while the involvement of structures like pre-cuneus, posterior cingulate, and frontal regions are in agreement with functional networks related loss of awareness. That bilateral amygdala swelling occurs in HWE is a novel observation and may signal that it could be a distinct variant of Mesial TLE.

Effects of Chronic Carbamazepine Treatment on the ECG in Patients with Focal Seizures

Background and Objectives

Several mechanisms have been proposed for the sudden unexpected death in epilepsy patients, such as cardiac arrhythmias, a decrease in heart rate variability and the use of anti-epileptic drugs (AEDs). Although carbamazepine is commonly used as an AED, the exact working mechanism of this drug as well as its effect on the heart are not completely understood. The aim of this study was to determine whether chronic carbamazepine therapy in patients with focal seizures and impaired awareness has an effect on the electrocardiogram (ECG).

Subjects and Methods

This cross-sectional study included 36 patients with focal seizures and impaired awareness treated for 12–32 months with carbamazepine monotherapy and 38 healthy volunteers. A 5-min modified three-electrode chest lead ECG with lead II configuration was recorded using LabChart 7 ECG software module at 1000-Hz sampling frequency. All data analysis was performed using custom-made Matlab 2015b scripts. ECGs of patients and controls were compared with respect to heart rate, time intervals and measures of short- and long-term variation.

Results

There were no significant differences in heart rate and ECG time intervals between the patient and control groups. Measures on short- and long-term variability also did not show any significant group differences.

Conclusion

Our study shows that chronic use of carbamazepine as monotherapy does not have any significant effects on ECG time intervals or measures of short- and long-term variability.

Heart rate variability measurement in epilepsy: How can we move from research to clinical practice?

Our objective was to critically evaluate the literature surrounding heart rate variability (HRV) in people with epilepsy and to make recommendations as to how future research could be directed to facilitate and accelerate integration into clinical practice. We reviewed relevant HRV publications including those involving human subjects with seizures. HRV has been studied in patients with epilepsy for more than 30 years and, overall, patients with epilepsy display altered interictal HRV, suggesting a shift in autonomic balance toward sympathetic dominance. This derangement appears more severe in those with temporal lobe epilepsy and drug-resistant epilepsy. Normal diurnal variation in HRV is also disturbed in at least some people with epilepsy, but this aspect has received less study. Some therapeutic interventions, including vagus nerve stimulation and antiepileptic medications, may partially normalize altered HRV, but studies in this area are sometimes contradictory. During seizures, the changes in HRV may be complex, but the general trend is toward a further increase in sympathetic overactivity. Research in HRV in people with epilepsy has been limited by inconsistent experimental protocols and studies that are often underpowered. HRV measurement has the potential to aid clinical epilepsy management in several possible ways. HRV may be useful in predicting which patients are likely to benefit from surgical interventions such as vagus nerve stimulation and focal cerebral resection. As well, HRV could eventually have utility as a biomarker of risk for sudden unexpected death in epilepsy (SUDEP). However, at present, the inconsistent measurement protocols used in research are hindering translation into clinical practice. A minimum protocol for HRV evaluation, to be used in all studies involving epilepsy patients, is necessary to eventually allow HRV to become a useful tool for clinicians. We propose a straightforward protocol, involving 5-minute measurements of root mean square of successive differences in wakefulness and light sleep.

Physiology Of Drowning: A Review

Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning.

Autonomic function in reflex and non-reflex epilepsy--an exploratory study

PURPOSE

Seizures are known to affect diverse areas of the Central Autonomic Network (CAN) resulting in varied autonomic symptoms. The objectives of the study were to characterize neuro-cardiac autonomic regulation in hot water epilepsy (HWE) with or without spontaneous seizure, and to analyze the effect of Carbamazepine (CBZ).

METHODS

Seventy patients of HWE [42 drug-naïve 'HWE only' and 28 'HWE with spontaneous complex partial seizure (CPS),' on CBZ] and 40 spontaneous CPS on CBZ were recruited after informed consent. Fifty healthy volunteers served as control. Conventional cardiac autonomic function tests, Heart Rate Variability (HRV), Blood Pressure Variability (BPV), and baroreflex sensitivity (BRS) were performed.

RESULTS

Significant dysfunction was evidenced in most of the autonomic function parameters in all the epilepsy subgroups when compared with controls. Significant reduction in the parasympathetic activity in HWE patients was observed. Significant impairment of short-term fluctuation of blood pressure in 'HWE with spontaneous CPS' compared to 'healthy volunteers' was detected. Compared to 'HWE only', 'HWE with spontaneous CPS' showed impaired sympathovagal balance. The BRS were also altered in 'HWE with spontaneous CPS' compared to 'HWE only'. The comparison of 'spontaneous CPS' with 'HWE with spontaneous CPS' and 'HWE only' showed reduced parasympathetic and sympathetic activities.

CONCLUSION

Both cardiovascular reflexes and autonomic cardiovascular regulation were altered in HWE, more so in 'HWE with spontaneous seizures'. Compared to those on CBZ, drug naïve had severe effect on vagal tone and CBZ did not alter cardiac autonomic functions in reflex as well as in non-reflex epilepsies.

Monitoring peri-ictal changes in heart rate variability, oxygen saturation and blood pressure in epilepsy monitoring unit

PURPOSE

The peri-ictal autonomic disturbances have been studied as predictors of seizure outcome and as markers of seizure onset. We studied the changes in heart rate (HR), HRV, oxygen saturation and blood pressure (BP) in the peri-ictal period in patients with drug-resistant localization-related epilepsy.

METHODOLOGY

Ninety one subjects undergoing video-EEG monitoring, underwent continuous HR, SpO2, BP and Lead II ECG monitoring. The changes during the preictal, ictal and postictal periods were analyzed for 57 seizures in 42 patients with artifact-free recordings and correlated with VEEG ictal onset and MRI characteristics.

RESULTS

Ictal tachycardia was noted in 15 (26.3%) seizures, of which, 60% had temporal lobe onset. HR increased by an average of 20.1% from pre-ictal to ictal phases (p=0.04). Ictal bradycardia was noted in one event with right temporal seizure onset. Heart rate variability (HRV) analysis of the preictal, ictal and postictal phases showed an increase in the sympathetic and decrease in parasympathetic activity during the ictus with relatively preserved total power. Ictal oxygen desaturation (84.1%±3.5%) was noticed in 10 (17.5%) seizures. Ictal hypertension was observed in 15 (26.3%); ictal hypotension was noted in 5 (8.7%) seizures. Both the systolic BP and diastolic BPs increased from the pre-ictal to ictal phase (p=0.01).

CONCLUSIONS

Peri-ictal dysautonomia can present in variable patterns and can be measured and compared over different modalities such as BP, HR and HRV. Though degree of tachycardia and increase in BP were higher during extratemporal onset of seizures, a fall in variability was noted in seizures of temporal lobe origin. Oxygen desaturation is not an uncommon event during the peri-ictal period in localization related epilepsy.

Transcutaneous auricular vagus nerve stimulation for pediatric epilepsy: study protocol for a randomized controlled trial

Background

Recently, clinical observations reported the potential benefit of vagus nerve stimulation (VNS) for pediatric epilepsy. Transcutaneous auricular vagus nerve stimulation (ta-VNS) is a newer non-invasive VNS, making it more accessible for treating pediatric epilepsy, yet there is limited clinical evidence for its effectiveness.

Methods/Design

A three-center, randomized, parallel, controlled trial will be carried out to evaluate whether ta-VNS improves pediatric epilepsy. Pediatric patients aged 2 to 14 years with epilepsy will be recruited and randomly assigned to transcutaneous auricular vagus nerve stimulation (ta-VNS) group, transcutaneous auricular non-vagus nerve stimulation (tan-VNS) group, and control group with a 1:1: sqrt(2) allocation, as per a computer generated randomization schedule stratified by study center using permuted blocks of random sizes. We will use Zelen’s design, in which randomization occurs before informed consent. Patients in the stimulation groups will receive tan-VNS or ta-VNS three times a day for 6 months. Patients in the control group will not be provided with any stimulation during the 6 months. The guardians of the patients are required to keep a detailed diary to record the data. Outcome assessment including seizure frequency, electroencephalogram (EEG), heart rate variability (HRV) analysis, quality of life (QOL) and adverse events will be made at baseline and 2, 4 and 6 months after ta-VNS initiation. The seizure frequency and adverse events will be followed up at 1 year and 1.5 years after ta-VNS initiation.

Discussion

Results of this trial will help clarify whether ta-VNS treatment is beneficial for pediatric patients, and will make clear whether the anticonvulsive effect of ta-VNS is correlated with the improvement of sympathovagal imbalance.

Trial registration

Clinical Trials Identifier: NCT02004340. Registration date: 13 November 2013.

Electronic supplementary material

The online version of this article (doi:10.1186/s13063-015-0906-8) contains supplementary material, which is available to authorized users.

Hot water epilepsy: Phenotype and single photon emission computed tomography observations

We studied the anatomical correlates of reflex hot water epilepsy (HWE) using multimodality investigations viz. magnetic resonance imaging (MRI), electroencephalography (EEG), and single photon emission computed tomography (SPECT). Five men (mean age: 27.0 ΁ 5.8 years) with HWE were subjected to MRI of brain, video-EEG studies, and SPECT scan. These were correlated with phenotypic presentations. Seizures could be precipitated in three patients with pouring of hot water over the head and semiology of seizures was suggestive of temporal lobe epilepsy. Ictal SPECT showed hyperperfusion in: left medial temporal — one, left lateral temporal — one, and right parietal — one. Interictal SPECT was normal in all five patients and did not help in localization. MRI and interictal EEG was normal in all the patients. The clinical and SPECT studies suggested temporal lobe as the seizure onset zone in some of the patients with HWE.

Cardiac phenomena during kainic-acid induced epilepsy and lamotrigine antiepileptic therapy

RATIONALE

Pathologic ECG events are known to accompany seizures and to persist in several chronic epilepsy syndromes. The contribution of antiepileptic drugs (AEDs) to these events and the implications in the etiology of sudden-unexpected death in epilepsy (SUDEP) continue to be a matter of debate. We therefore investigated cardiac parameters during kainic-acid (KA) induced experimental epilepsy and antiepileptic treatment with lamotrigine (LTG).

METHODS

Epilepsy was induced in seven C57Bl/6 mice by injections of KA (20 mg/kg) on days 1 and 5, which produced severe acute seizures and spontaneous seizures 10 days later. Treatment with LTG (30 mg/kg) was initiated on day 11 and repeated on day 12. Continuous ECGs and ECoGs were collected telemetrically from freely moving mice.

RESULTS

Mice displayed pre-ictal but not ictal tachycardia. The squared coefficient of variation (SCV) of R-R intervals was significantly elevated 30s before and during seizures compared to control conditions. LTG produced a significant reversible increase in SCV and LF/HF ratio during slow-wave sleep (SWS), potentially indicative of sympatho-vagal imbalance during this state of vigilance, in which epileptic patients are known to be particularly vulnerable to SUDEP.

SIGNIFICANCE

The KA model used in this study permits the investigation of cardiac phenomena during epilepsy, as it features many effects found in human epileptic patients. Increased LF/HF, a known risk factor for cardiac disease, which is often found in epileptic patients, was observed as a side-effect of LTG treatment during SWS, suggesting that LTG may promote imbalance of the autonomous nervous system in epileptic mice.