Shasha Wu

Association of prone position with sudden unexpected death in epilepsy

Editors’ Note: “Association of prone position with sudden unexpected death in epilepsy” raised several inquiries from our readers. Sethi suggests that since the pathogenesis of sudden unexpected death in epilepsy (SUDEP) is not yet elucidated, advising patients to sleep in the supine position, which risks aspiration, warrants careful consideration. Furthermore, based on their prior study, Lhatoo et al. believe that forced ictal version, rather than prone position, may be a SUDEP risk factor. Authors Tao et al. argue that supine sleeping can help prevent SUDEP and, although it could be associated with aspiration, babies seizing facedown risk suffocation. —Chafic Karam, MD, and Robert C. Griggs, MD

Role of ictal baseline shifts and ictal high-frequency oscillations in stereo-electroencephalography analysis of mesial temporal lobe seizures

To assess the role of ictal baseline shifts (IBS) and ictal high‐frequency oscillations (iHFOs) in intracranial electroencephalography (EEG) presurgical evaluation by analysis of the spatial and temporal relationship of IBS, iHFOs with ictal conventional stereo‐electroencephalography (icEEG) in mesial temporal lobe seizures (MTLS).

Peripheral sounds rapidly activate visual cortex: evidence from electrocorticography

Neurophysiological studies with animals suggest that sounds modulate activity in primary visual cortex in the presence of concurrent visual stimulation. Noninvasive neuroimaging studies in humans have similarly shown that sounds modulate activity in visual areas even in the absence of visual stimuli or visual task demands. However, the spatial and temporal limitations of these noninvasive methods prevent the determination of how rapidly sounds activate early visual cortex and what information about the sounds is relayed there. Using spatially and temporally precise measures of local synaptic activity acquired from depth electrodes in humans, we demonstrate that peripherally presented sounds evoke activity in the anterior portion of the contralateral, but not ipsilateral, calcarine sulcus within 28 ms of sound onset. These results suggest that auditory stimuli rapidly evoke spatially specific activity in visual cortex even in the absence of concurrent visual stimulation or visual task demands. This rapid auditory-evoked activation of primary visual cortex is likely to be mediated by subcortical pathways or direct cortical projections from auditory to visual areas.

Periictal autonomic dysfunction and generalized postictal EEG suppression in convulsive seizures arising from sleep and wakefulness

Sleep appears to be an independent risk factor of sudden unexpected death in epilepsy (SUDEP). We retrospectively determined the periictal electrophysiological characteristics of nocturnal and diurnal generalized convulsive seizures (GCSs) in 109 patients. Our data showed that preictal heart rate (HR) was significantly lower in 46 patients with nocturnal GCSs than in 63 patients with diurnal GCSs (p=0.002). However, there was no significant difference in postictal HR and respiratory rate (RR), total seizure duration, total convulsive phase, tonic phase, and clonic phase. Meanwhile, postictal generalized EEG suppression (PGES) was observed in 52.4% of the patients with diurnal GCSs and 67.4% of the patients with nocturnal GCSs. Duration of PGES was 38.2±17.3s in patients with diurnal GCSs and 49.5±21.7s in patients with nocturnal GCSs. There was also no significant difference in the prevalence (p=0.118) and duration (p=0.044, Bonferroni-corrected significant level: α=0.00625) of PGES in the two patient groups. Therefore, there is no clear evidence to attribute the SUDEP risk associated with sleep to postictal autonomic dysfunction and PGES, as compared to wakefulness.

Should the "Back to Sleep" campaign be advocated for SUDEP prevention?

Sudden unexpected death in epilepsy (SUDEP) is a devastating complication of epilepsy and a leading cause of premature death in patients with chronic uncontrolled epilepsy [1]. Over a period of 40 years, the risk of SUDEP is 12% in peoplewith uncontrolled epilepsy [2]. Comparing years of potential life lost from SUDEP with other neurological diseases, SUDEP ranks second only to stroke [3]. Sudden unexpected death in epilepsy usually occurs during sleep, in bed, and as an unwitnessed event. Patients are commonly found in the face-down, prone position. These circumstances surrounding SUDEP are remarkably similar to those of sudden infant death syndrome (SIDS). Emerging evidence has suggested that prone positionmay be a significant risk factor for SUDEP. This observationwas initially reported in 1868 by G. Mackenzie Bacon who described SUDEP as “death in a fit”, which may arise from suffocation due to the face being buried in the pillow or any softmaterials [4]. Since then, a number of case reports and case series have documented that a significant proportion of victims died in the prone position, ranging from 42% to 81% [5–7]. A recent systematic review and meta-analysis of 25 publications found that 73.3% (95% CI = 65.7%, 80.9%) of 253 SUDEP victims died in the prone position. Strikingly, the prone position was reported in all 11 cases of patients who were monitored by video-EEG during SUDEP. The association between a facedown position and SUDEP was statistically significant (p b 0.001). Additionally, in a subset of 88 patients, the prone position was observed in 86% of those aged 40 or younger but only in 60% of patients older than 40. The chances of dying facedown were almost 4 times higher in the younger patient group than in the older patient group (odds ratio= 3.9; 95% CI= 1.4%, 11.4%; p=0.009) [8]. These findings demonstrated that SUDEP may share mechanisms similar to SIDS and is thus most likely preventable. Although the mechanisms underlying SUDEP remain poorly understood, it has become increasingly clear that SUDEP is a heterogeneous disorder [9]. Seizures frequently induce prominent periictal cardiovascular and respiratory dysfunction [10–12]. It is likely that some cases of SUDEP result from fatal cardiac arrhythmias, while others are caused by respiratory depression and central apnea. However, primary cardiorespiratory failure secondary to a seizure does not fit well as a principal SUDEP mechanism given the overwhelming prevalence of a terminal prone position. Cases that weremonitored by video-EEG have provided us with the most valuable insights into the mechanism of SUDEP [13]. Striking similarities have been observed in all such monitored cases, namely a generalized tonic–clonic seizure (GTCS), postictal generalized EEG suppression (PGES), and a terminal proneposition. These commonalities are unlikely to be simply a matter of chance, given that these monitored SUDEP cases have been randomly reported over a period of 25 years. Instead, they likely reflect a common mechanism.

Impact of periictal nurse interventions on postictal generalized EEG suppression in generalized convulsive seizures.

OBJECTIVES The objective of this study was to determine the impact of periictal nurse interventions on postictal generalized EEG suppression (PGES) in generalized convulsive seizures (GCS). METHODS We retrospectively reviewed the video-EEG recordings of patients during long-term video-EEG monitoring. We compared the duration of seizures, seizure phases (tonic, clonic, and tonic-clonic phases), and the occurrence and duration of postictal generalized EEG suppression (PGES) in patients with and without periictal interventions (e.g., oxygen administration, suctioning, and repositioning). Statistical analyses were performed to determine the association between the seizure-related variables and the periictal interventions. RESULTS A total of 109 patients with 150 GCS were included in the study. Periictal interventions were provided in 122 GCS, of which, ictal administration of oxygen was provided in 29 GCS. The duration of PGES was significantly shortened in GCS with interventions when compared with those without interventions (p=0.003). However, the ictal administration of oxygen, assessed as an independent variable, did not influence the occurrence or duration of PGES. CONCLUSION Periictal interventions significantly shortened the duration of PGES, and may, as a consequence, reduce the risk of SUDEP. However, ictal administration of oxygen did not influence the occurrence or duration of PGES.

Stereotactic EEG-guided laser interstitial thermal therapy for mesial temporal lobe epilepsy

Objective To determine the outcomes of combined stereo-electroencephalography-guided and MRI-guided stereotactic laser interstitial thermal therapy (LITT) in the treatment of patients with drug-resistant mesial temporal lobe epilepsy (mTLE). Methods We prospectively assessed the surgical and neuropsychological outcomes in 21 patients with medically refractory mTLE who underwent LITT at the University of Chicago Medical Center. We further compared the surgical outcomes in patients with and without mesial temporal sclerosis (MTS). Results Of the 21 patients, 19 (90%) underwent Invasive EEG study and 11 (52%) achieved freedom from disabling seizures with a mean duration of postoperative follow-up of 24±11 months after LITT. Eight (73%) of 11 patients with MTS achieved freedom from disabling seizures, whereas 3 (30 %) of 10 patients without MTS achieved freedom from disabling seizures. Patients with MTS were significantly more likely to become seizure-free, as compared with those without MTS (P=0.002). There was no significant difference in total ablation volume and the percentage of the ablated amygdalohippocampal complex between seizure-free and non-seizure-free patients. Presurgical and postsurgical neuropsychological assessments were obtained in 10 of 21 patients. While there was no group decline in any neuropsychological assessment, a significant postoperative decline in verbal memory and confrontational naming was observed in individual patients. Conclusions MRI-guided LITT is a safe and effective alternative to selective amygdalohippocampectomy and anterior temporal lobectomy for mTLE with MTS. Nevertheless, its efficacy in those without MTS seems modest. Large multicentre and prospective studies are warranted to further determine the efficacy and safety of LITT.

Antiglutamic acid decarboxylase 65 (GAD65) antibody-associated epilepsy

Glutamic acid decarboxylase (GAD) antibody-associated encephalitis causes both acute seizures and chronic epilepsy with predominantly temporal lobe onset. This condition is challenging in diagnosis and management, and the incidence of GAD antibody (Ab)-related epilepsy could be much higher than commonly believed. Imaging and CSF evidence of inflammation along with typical clinical presentations, such as adult onset temporal lobe epilepsy (TLE) with unexplained etiology, should prompt testing for the diagnostic antibodies. High serum GAD Ab titer (≥2000U/mL or ≥20nmol/L) and evidence of intrathecal anti-GAD Ab synthesis support the diagnosis. Unlike other immune-mediated epilepsies, antiglutamic acid decarboxylase 65 (GAD65) antibody-mediated epilepsy is often poorly responsive to antiepileptic drugs (AEDs) and only moderately responsive to immune therapy with steroids, intravenous immunoglobulin (IVIG), or plasma exchange (PLEX). Long-term treatment with more aggressive immunosuppressants such as rituximab (RTX) and/or cyclophosphamide is often necessary and may be more effective than current immunosuppressive approaches. The aim of this review is to review the physiology, pathology, clinical presentation, related ancillary tests, and management of GAD Ab-associated autoimmune epilepsy by searching the keywords and to promote the recognition and the initiation of proper therapy for this condition.

Homonymous hemianopsia after MR-guided stereotactic laser amygdalohippocampectomy

Magnetic resonance-guided laser interstitial thermal therapy (LITT) is a minimally invasive technique that can create lesions in the mesial temporal structures with little damage to surrounding tissues. Early data suggest that LITT is associated with favorable surgical outcomes and superior preservation of cognitive function in patients with mesial temporal lobe epilepsy [1–4]. Therefore, LITT is a promising alternative to traditional anterior temporal lobectomy and selective

MR-Guided Laser Interstitial Thermal Therapy for the Treatment of Medically Refractory Epilepsy

Resective epilepsy surgery is highly effective in the treatment of medically refractory epilepsy. However, it involves an open craniotomy and carries the risks of permanent functional deficits and cosmetic concerns. Multiple minimally invasive surgical approaches have been attempted to destroy seizure foci with minimal damage to surrounding normal tissue. Here we review the currently available minimally invasive surgical approaches for epilepsy, with an emphasis on MR-guided laser interstitial thermal therapy (MRgLITT). The results from multiple centers are reviewed and our center’s experiences with MRgLITT are reported to highlight the advantages and limitations of this new technology.