[Bradycardia as an epileptic manifestation in temporal epilepsy: report of a case]

Dysautonomia in people with epilepsy: A scoping review

BACKGROUND

Epilepsy is one of the most common neurological diseases and has high morbidity and mortality. Multiple methods for assessing dysautonomia have been reported; however, the patient characteristics and epilepsy features that drive any method selection are unclear. People with epilepsy (PWE) can experience sudden unexpected death in epilepsy (SUDEP) and one reason can be dysautonomia. If dysautonomia can be detected in PWE before a severe event, then it could complement and redirect patient treatment and monitoring.

OBJECTIVE

To map the available literature on dysautonomia in PWE and describe patients' characteristics and methods used to evaluate dysautonomia.

METHODS

We performed a scoping literature review. We searched PubMed, Scopus, Embase, and hand searched starting from the first registry in the literature until August 2019. Studies were independently assessed by three authors and two epileptologists. We present data in tables and summarize information according to the following structure: population, concepts, and context.

RESULTS

Thirty-five studies were included in the analysis with epidemiological designs including case reports (23), cross-sectional studies (4), case‒controls (7), and cohort studies (1). A total of 618 patients were enrolled. Heart rate variability, arrhythmia, blood pressure, the tilt-table test, polysomnography, respiratory function, and magnetic resonance imaging were the methods most commonly used to assess dysautonomia in PWE. A detailed description of the heart rate variability assessment is presented.

CONCLUSIONS

This review provides a broad description of the available literature identifying clinical findings, the most frequently reported assessment measurements of dysautonomia, in temporal lobe epilepsy and extratemporal epilepsies.

Occurrence and lateralizing value of "rare" peri-ictal vegetative symptoms in temporal lobe epilepsy

We retrospectively investigated rare peri-ictal vegetative symptoms (PIVS) in 380 seizures of 97 patients with temporal lobe epilepsy (TLE): 234 seizures of 60 patients with TLE with mesiotemporal sclerosis (TLE/MTS) and 146 seizures of 37 patients with TLE with other lesions (TLE/non-MTS) who were at least 2 years after epilepsy surgery and classified as Engel I. We assessed the following PIVS: peri-ictal cough (pC), peri-ictal water drinking (pWD), peri-ictal vomiting (pV), and peri-ictal spitting (pS). We observed pC in 24.7% of patients and 10% of seizures; pWD in 14.4% of patients and 5.9% of seizures; pV and pS occurred more rarely. Both pWD and pC occurred significantly more often in those with TLE of the non- language-dominant hemisphere. The limited occurrence of pV and pS made it impossible to perform statistical analysis for these symptoms. In patients with TLE, pC and pWD were quite frequent; we observed pV and pS less frequently. Both pC and pWD have a significant lateralizing value in TLE.

The ictal bradycardia syndrome: localization and lateralization

PURPOSE

Previous studies have established the importance of the insular cortex and temporal lobe in cardiovascular autonomic modulation. Some investigators, based on the results of cortical stimulation response, functional imaging, EEG recordings of seizures, and lesional studies, have suggested that cardiac sympathetic and parasympathetic function may be lateralized, with sympathetic representation lateralized to the right insula, and parasympathetic, to the left. These studies have suggested that ictal bradycardia is most commonly a manifestation of activation of the left temporal and insular cortex. However, the evidence for this is inconsistent. We sought to assess critically the predictable value of ictal bradycardia for seizure localization and lateralization.

METHODS

In this study, we reviewed the localization of seizure activity in 13 consecutive patients with ictal bradycardia diagnosed during prolonged video-EEG monitoring at Mayo Clinic Rochester. The localization of electrographic seizure activity at seizure onset and bradycardia onset was identified in all patients. In addition, we performed a comprehensive review of the ictal bradycardia literature focusing on localization of seizure activity in ictal bradycardia cases.

RESULTS

All occurrences of ictal bradycardia in the 13 identified patients were associated with temporal lobe-onset seizures. However, no consistent lateralization of seizure activity was found at onset of seizure activity or at onset of bradycardia in this population. Seizure activity was bilateral at bradycardia onset in nine of 13 patients. The results from the literature review also showed that a predominance of patients had bilateral activity at bradycardia onset; however, more of the ictal bradycardia cases from the literature had left hemispheric localization of seizure onset.

CONCLUSIONS

Ictal bradycardia most often occurs in association with bilateral hemispheric seizure activity and is not a consistent lateralizing sign in localizing seizure onset. Our data do not support the existence of a strictly unilateral parasympathetic cardiomotor representation in the left hemisphere, as has been suggested.