A Neurological Cause of Recurrent Choking During Sleep

Seizure semiology: ILAE glossary of terms and their significance

This educational topical review and Task Force report aims to address learning objectives of the International League Against Epilepsy (ILAE) curriculum. We sought to extract detailed features involving semiology from video recordings and interpret semiological signs and symptoms that reflect the likely localization for focal seizures in patients with epilepsy. This glossary was developed by a working group of the ILAE Commission on Diagnostic Methods incorporating the EEG Task Force. This paper identifies commonly used terms to describe seizure semiology, provides definitions, signs and symptoms, and summarizes their clinical value in localizing and lateralizing focal seizures based on consensus in the published literature. Video-EEG examples are included to illustrate important features of semiology in patients with epilepsy.

Prolonged Video-EEG and Heart Rate Variability can Elucidate Autonomic Dysregulation in Infantile Apneic Seizures

BACKGROUND

Infantile apneic seizures (IASs) are unexpected life-threatening events. We aimed to determine the utility of prolonged video-electroencephalography (vEEG) and heart rate variability (HRV) in IAS.

METHODS

The study included seven infants with apneic seizures captured by vEEG, percutaneous oxygen saturation (SpO₂), and electrocardiography (ECG). Interictal, preictal, and postictal HRV of patients and N2 sleep HRV of 10 age-matched controls were determined.

RESULTS

We analyzed seven vEEGs (duration = 17 to 87 hours) of seven patients aged three to 13 months (mean onset age of apneic event = 6.3 months). Fifteen apneic seizures (one to five per infant) were captured. The initial apneic seizure was captured at 7.5 to 76 hours (mean = 36.6 hours) after vEEG initiation. Ictal rhythmic delta/theta/fast waves were seen over temporal (five patients), central (one), and diffuse areas (one). Ictal SpO₂ decreased between 1.5% and 90% (mean = 47.9%). Ictal decreased heart rate (HR) (six seizures) and ictal increased HR (14) was detected. Both decreased and increased HR was observed (five). The preictal low-frequency (LF)/high-frequency (HF) ratio was significantly higher than the interictal LF/HF ratio (P = 0.048). Preictal (P = 0.048), and postictal (P = 0.019) root mean square of successive differences (RMSSDs) of patients were lower than the sleep RMSSD of controls. These results indicated dominant sympathetic activity. RMSSD from interictal to preictal periods tended to be higher in IAS with decreased HR than in IAS with increased HR alone (P = 0.066). The postictal RMSSD showed tendency to be higher in IAS with decreased HR than in IAS with increased HR alone (P = 0.088). The decreased HR and increased RMSSD suggested not only sympathetic activity but also escalated parasympathetic activity in IAS.

CONCLUSIONS

Infants with unexpected apneic events should be monitored with prolonged vEEG, SpO₂, and ECG. Abnormal HRV in infants with apneic seizures might indicate additional autonomic dysregulation in IAS.

Aberrant Resting-State Functional Brain Connectivity of Insular Subregions in Obstructive Sleep Apnea

The insular cortex is a cortical regulatory area involved in dyspnea, cognition, emotion, and sensorimotor function. Previous studies reported that obstructive sleep apnea (OSA) shows insular tissue damage and abnormal functional connections for the whole insula. The insula can be divided into different subregions with distinct functional profiles, including the ventral anterior insula (vAI) participating in affective processing, dorsal anterior insula (dAI) involved in cognitive processing, and posterior insula (PI) involved in the processing of sensorimotor information. However, the functional connectivity (FC) of these insular subregions in OSA has yet to be established. Hence, the purpose of this study was to explore the resting-state FC of the insular subregions with other brain areas and its relationship with clinical symptoms of OSA. Resting-state functional magnetic resonance imaging data from 83 male OSA patients and 84 healthy controls were analyzed by whole-brain voxel-based FC using spherical seeds from six insular subregions, namely, the bilateral vAI, dAI, and PI, to identify abnormalities in the insular subregions network and related brain regions. Ultimately, the Pearson correlation analysis was carried out between the dysfunction results and the neuropsychological tests. Compared with the healthy control group, the OSA patients exhibited disturbed FC from the dAI to areas relevant to cognition, such as the bilateral cerebellum posterior lobe, superior frontal gyrus, right middle frontal gyrus and middle temporal gyrus; decreased FC from the vAI to areas linked with emotion, such as the bilateral fusiform gyrus, superior parietal lobule, precuneus and cerebellum posterior lobe; and abnormal FC from the PI to the brain regions involved in sensorimotor such as the bilateral precentral gyrus, right superior/middle temporal gyrus and left superior frontal gyrus. The linear regression result showed that the apnea-hypopnea index was positively correlated with the increased FC between the right PI and the right precuneus (after Bonferroni correlation, P < 0.001) In conclusion, the abnormal FC between insular subregions and other brain regions were related to cognitive, emotional and sensorimotor networks in OSA patients. These results may provide a new imaging perspective for further understanding of OSA-related cognitive and affective disorders.

A review of magnetoencephalography use in pediatric epilepsy: an update on best practice

Introduction: Magnetoencephalography (MEG) is a noninvasive technique that is used for presurgical evaluation of children with drug-resistant epilepsy (DRE).Areas covered: The contributions of MEG for localizing the epileptogenic zone are discussed, in particular in extra-temporal lobe epilepsy and focal cortical dysplasia, which are common in children, as well as in difficult to localize epilepsy such as operculo-insular epilepsy. Further, the authors review current evidence on MEG for mapping eloquent cortex, its performance, application in clinical practice, and potential challenges.Expert opinion: MEG could change the clinical management of children with DRE by directing placement of intracranial electrodes thereby enhancing their yield. With improved identification of a circumscribed epileptogenic zone, MEG could render more patients as suitable candidates for epilepsy surgery and increase utilization of surgery.

Insular seizures and epilepsies: Ictal semiology and minimal invasive surgery

PURPOSE OF REVIEW

The increased identification of seizures with insular ictal onset, promoted by the international development of stereo-electroencephalography (SEEG), has led to the recent description of larger cohorts of patients with insular or insulo-opercular epilepsies than those previously available. These new series have consolidated and extended our knowledge of the rich ictal semiology and diverse anatomo-clinical correlations that characterized insular seizures. In parallel, some experiences have been gained in the surgical treatment of insular epilepsies using minimal invasive procedures.

RECENT FINDINGS

The large majority of patients present with auras (mostly somatosensory and laryngeal) and motor signs (predominantly elementary and orofacial), an underlying focal cortical dysplasia, and an excellent postoperative seizure outcome. Many other subjective and objective ictal signs, known to occur in other forms of epilepsies, are also observed and clustered in five patterns, reflecting the functional anatomy of the insula and its overlying opercula, as well as preferential propagation pathways to frontal or temporal brain regions. A nocturnal predominance of seizure is frequently reported, whereas secondary generalization is infrequent. Some rare ictal signs are highly suggestive of an insular origin, including somatic pain, reflex seizures, choking spells, and vomiting. Minimal invasive surgical techniques have been applied to the treatment of insular epilepsies, including Magnetic Resonance Imaging-guided laser ablation (laser interstitial thermal therapy (LITT)), radiofrequency thermocoagulation (RFTC), gamma knife radiosurgery, and responsive neurostimulation. Rates of seizure freedom (about 50%) appear lower than that reported with open-surgery (about 80%) with yet a significant proportion of transient neurological deficit for LITT and RFTC.

SUMMARY

Significant progress has been made in the identification and surgical treatment of insular and insulo-opercular epilepsies, including more precise anatomo-clinical correlations to optimally plan SEEG investigations, and experience in using minimal invasive surgery to reduce peri-operative morbidity.

Stereo-EEG exploration in the insula/operculum in paediatric patients with refractory epilepsy

PURPOSE

Failure to recognise involvement of the insula / opercula (I/O) region is associated with poor outcome in epilepsy surgery. Recognition is challenging due to high connectivity with adjacent structures resulting in variable and misleading semiology, often subjective and therefore likely to be underreported by children. In this study we explored prevalence and characteristics of I/O involvement in paediatric patients undergoing sEEG exploration.

METHOD

We retrospectively included all consecutive patients undergoing sEEG at our centre between 11/2014 and 01/2018 with at least three contacts within I/O and excluded those with undetermined seizure onset zone (SOZ) by sEEG. We divided patients into three groups: 1) SOZ in I/O, 2) spread to I/O and 3) no I/O involvement. We compared pre-invasive characteristics, sEEG results, surgery and outcome for each group.

RESULTS

29 of all 53 consecutive patients had an identified SOZ by sEEG and at least three contacts within the I/O and were included. 41% had I/O SOZ, 38% had I/O spread and 21% had no I/O involvement. Insula associated symptoms described in adult literature were not statistically different between the three groups. Complications due to sEEG were low (2 of 53 patients). Following I/O surgery, 63% were seizure free while an additional 26% of patients achieved seizure reduction. Postoperative deficits were seen in 75% of the patients but completely resolved in all but one patient.

CONCLUSIONS

Our data suggest an important role of the I/O region with frequent onset or propagation to the I/O region (at least 64% of all 53 sEEG cases). Semiology appears less specific than in adults. Insula depth electrode insertion is safe with subsequent good surgical outcomes albeit common transient deficits.

Nocturnal frontal lobe epilepsy presenting as obstructive type sleep apnea

A 20-year-old man presented with sleep apnea. Polysomnography was performed and it revealed nine apneas and two hypopneas. Contrary to typical apnea, however, rhythmic epileptiform discharges appeared at bifrontal area on EEG just before the start of apnoea. Video-EEG monitoring was performed to classify these events, and to evaluate the relationship of apnoea and ictal discharge. Ictal EEG revealed paroxysmal fast activity over the bifrontal area. Ictal SPECT showed hyperperfusion in right frontal area. Given these findings, we concluded that these events were epileptic seizures presenting as obstructive sleep apnea. Antiepileptic medication was initiated, and the events were decreased. This case demonstrates that nocturnal frontal love epilepsy may be the potential cause of obstructive sleep apnea (OSA).

Nocturnal choking episodes: under-recognized and misdiagnosed

Causes of nocturnal paroxysmal events include a variety of disorders such as epileptic seizures, parasomnias, sleep-related movement disorders, and psychiatric disturbances. Timing and semiology of the events, simultaneous video-electroencephalographic observation, presence of any daytime events, and relevant psychiatric and medical history may help in sorting out various possibilities considered in the differential diagnosis of such events. Timely diagnosis of these events is crucial for appropriate management; under-recognition and misdiagnosis of nonepileptic events is not uncommon. Described here are two cases within the spectrum of nocturnal paroxysmal events, one with nocturnal panic attacks and the other with frontal lobe epilepsy, each presenting with choking episodes.