Siew-Na Lim

Electrical stimulation of the anterior nucleus of the thalamus for intractable epilepsy: a long-term follow-up study.

Summary:  Purpose: The anterior nucleus of the thalamus (ANT) modulates temporal lobe and hypothalamic activities, and relays information to the cingulate gyrus and entorhinal cortex. Deep brain stimulation (DBS) of the ANT has been reported to decrease seizure activity in a limited number of human subjects. However, long‐term effect of chronic ANT stimulation on such patients remains unknown. We report long‐term follow‐up results in four patients receiving ANT stimulation for intractable epilepsy.

Contact heat evoked potentials in normal subjects.

Laser-evoked potentials are widely used to investigate nociceptive pathways. The newly developed contact heat stimulator for evoking brain response has the advantages of obtaining reliable scalp potentials and absence of cutaneous lesions. This study aimed to identify the most appropriate stimulation site with consistent cortical responses, and to correlate several parameters of the contact heat evoked potentials (CHEPs) with age, gender, and body height in normal subjects. CHEPs were recorded at Cz with a contact heat stimulator (Medoc, Israel) in 35 normal controls. The subjects were asked to keep eyes open and remain alert. The baseline temperature was 32 degrees C, and stimulation peak heat intensity of 51 degrees C was applied to five body sites: bilateral forearm, right dorsum hand, right peroneal area, and right dorsum foot. Reproducible CHEPs were recorded more frequently when stimulated at volar forearm (62.5%) than at the lower limbs (around 40%). The first negative peak latency (N1) was 370.1 +/- 20.3 ms, first positive peak latency (P1) was 502.4 +/- 33.0 ms, and peak to peak amplitude was 10.2 +/- 4.9 microV with stimulation of the forearm. Perceived pain intensity was not correlated with the presence or amplitude of CHEPs. No gender or inter-side differences were observed for N1 latency and N1-P1 amplitude. Also, no correlation was noted between N1 and age or body height. These results support future clinical access of CHEPs as a diagnostic tool.

Low and High Frequency Hippocampal Stimulation for Drug-Resistant Mesial Temporal Lobe Epilepsy.

Electrical stimulation of the hippocampus offers the possibility to treat patients with mesial temporal lobe epilepsy (MTLE) who are not surgical candidates. We report long‐term follow‐up results in five patients receiving low or high frequency hippocampal stimulation for drug‐resistant MTLE.

Duration of electroencephalographic recordings in patients with epilepsy

PURPOSE Previous studies have demonstrated different diagnostic yields with electroencephalography (EEG). Due to the small sample sizes or different patient populations (outpatients or inpatients only) in these previous studies, the clinical use of routine EEG and outpatient/inpatient video-EEG monitoring (VEM) needs further clarification. In this study, we investigated EEGs obtained from patients referred by epileptologists; by comparing the results of different EEG methods, we sought to determine the optimal durations and specific types of EEG recordings for different clinical situations. METHODS The data from 335 routine EEGs, 281 3 h outpatient VEMs, and 247 inpatient VEMs (>48 h) were reviewed. We analyzed the latency to the first epileptiform discharge or clinical event. RESULTS In patients undergoing outpatient VEMs, 48% of the first epileptiform discharges appeared within 20 min, and 64% appeared within 30 min. In patients undergoing inpatient VEMs, 21.2% had their first attack within 3h. The second peak of event occurrence was during the 33rd-36th h. Only 3.5% of the seizures were recorded after 57 h. The detection rate of epileptiform discharges was higher for 3h outpatient VEM than for routine EEG (54.1% versus 16.4%, p<0.01). Epileptic and/or nonepileptic events were recorded in 45.8% of the inpatient VEMs, the diagnostic yield of which was higher than for outpatient VEMs (p<0.01). Since the patients in this study had been selected to limit the bias between each group, the diagnostic yield of EEGs in this study are likely to have been higher than those found in routine practice. Patients with generalized epilepsy had a shorter latency to the first epileptiform discharge compared to patients with localization-related epilepsy (mean, 22.1 min versus 33.9 min, p<0.05). CONCLUSIONS Two-thirds of epileptiform discharges were detected within 30 min of VEM. A 30-min recording is recommended for routine EEG examinations that aim to detect epileptiform discharges. A 3h outpatient VEM is a reasonable option when a routine EEG fails to detect epileptiform discharges. The latency to the first epileptiform discharge was shorter in patients with generalized epilepsy than in patients with localization-related epilepsy. 48 h of inpatient VEM might be adequate for detecting the target events.

Successful Treatment of Refractory Status Epilepticus Using Anterior Thalamic Nuclei Deep Brain Stimulation

BACKGROUND Refractory status epilepticus (RSE) is considered a medical emergency in neurology and is related to high mortality. We report a successfully treated case of RSE using deep brain stimulation (DBS) at the anterior thalamic nuclei (ATN) in a 17-year-old woman. RESULTS This patient developed RSE as a result of progressive seizure activity. RSE with generalized tonic-clonic seizures was noted 2 weeks before admission. Video electroencephalography monitoring showed continuous 3-Hz generalized spike-and-wave complexes with higher amplitude over bilateral frontal. Four weeks after RSE onset, bilateral DBS of the ATN was started. This treatment was immediately followed by the disappearance of tonic-clonic seizures and spike-and-wave complexes, suggesting resolution of the RSE. Significant clinical improvement was noted 1 week after DBS implantation. CONCLUSIONS DBS at the ATN significantly improved both the electroencephalography and clinical presentation in the patient with RSE. DBS at the ATN should be considered as a possible treatment choice once a patient develops RSE.

Clinical correlation and prognostic implication of periodic EEG patterns: A cohort study

OBJECTIVE Despite increasing amounts of research on periodic discharges (PDs), large clinical studies regarding their prognostic value are lacking. The aim of the current study was to evaluate the clinical implications and prognostic value of PDs. METHODS In this single-center retrospective cohort study, we included patients who underwent electroencephalographic recording either during hospitalization or from our outpatient clinics. Demographic data, associated seizure events, use of antiepileptic drugs, and outcomes at discharge were analyzed. Multivariate logistic regression analysis was used to evaluate associations between clinical factors and functional outcomes. RESULTS Four hundred and twenty patients were enrolled during a 17-year period, with a mean age of 66 years. The main etiologies included systemic infection (24%), anoxia (15%), and ischemic stroke (12%). Recent seizures were identified in 283 patients (67%), of whom 84 (30%) had status epilepticus. One hundred and fifty-four patients (37%) did not survive to hospital discharge. In multivariate analysis, old age (>65years; OR=2.55; 95% CI=1.57-4.16; P<0.001) was the strongest predictor of mortality, followed by systemic infection, anoxic encephalopathy, cefepime encephalopathy, and the occurrence of status epilepticus. Conversely, the use of antiepileptic drugs was negatively associated with mortality (OR=0.50; 95% CI=0.28-0.87; P=0.02). CONCLUSIONS PDs were associated with high rates of comorbidities and recent seizures, while the use of antiepileptic drugs was associated with a lower rate of mortality.

Extracranial Carotid Artery Disease Risk Factors and Outcomes in Patients With Acute Critical Hemispheric Ischemic Stroke

The prevalence of carotid disease in stroke patients has been underestimated because most stroke patients who receive carotid sonography have already survived the acute event. Little is known about the extracranial carotid arteries of patients with acute stroke who need intensive care. This study reviewed color‐coded carotid duplex sonographic examinations of the extracranial carotid arteries of patients with acute critical hemispheric ischemic stroke.

A randomized, double-blind, double-dummy, multicenter trial comparing the efficacy and safety of extended- and immediate-release levetiracetam in people with partial epilepsy

PURPOSE The aim of this trial was to compare the efficacy and safety of two formulations of levetiracetam in people with partial epilepsy over a 12-week treatment period. METHODS We performed a randomized, paralleled, and multicenter trial that consisted of a 4-week single-blind placebo run-in, followed by a 12-week double-blind, double-dummy treatment phase to compare the efficacy and safety of levetiracetam extended-release (LEV-ER) and immediate-release (LEV-IR) tablets as an adjunctive treatment in adult patients with uncontrolled epilepsy. RESULTS The median partial-onset seizure (POS) frequency per week (min-max) was 0.3 (0.0, 17.4; 95% confidence interval [95% CI] 1.3, 4.8) in the LEV-ER group and 0.3 (0.0, 31.4; 95% CI - 0.1, 4.3) in the LEV-IR group. No serious adverse events occurred during the trial period. Both groups had the same responder rate (58.6%), while a higher rate of seizure freedom over the treatment period was noted in the LEV-ER group compared with the LEV-IR group (27.6% vs. 13.8%, respectively). The European Quality of Life-5 Dimensions scores significantly increased in the LEV-ER-treated group, in contrast to the scores in the LEV-IR group, which decreased (7.2 vs. - 1.5, p = 0.03). CONCLUSION These results suggest that LEV-ER is equivalent to LEV-IR in reducing the frequency of POS and has a similar tolerability as LEV-IR as an add-on therapy. In addition, LEV-ER treatment improved the health-related quality of life of people with uncontrolled partial epilepsy.

Efficacy and tolerability of perampanel in children and adolescents with pharmacoresistant epilepsy: The first real-world evaluation in Asian pediatric neurology clinics

AIM This study investigated the efficacy and safety of perampanel (PER) adjunctive therapy in pediatric patients with epilepsy whose seizures are pharmacoresistant to existing antiepileptic drugs. METHODS A clinical retrospective study was conducted from 2016 to 2017 in the pediatric neurology clinic at a tertiary childrens hospital. We reviewed the data obtained from 66 children whose seizures were pharmacoresistant to more than two antiepileptic drugs, and could be followed up for a minimum of 3 months after PER adjunctive therapy initiation. The efficacy was estimated by the PER response rate at 3-, 6-, and 12-month follow-up evaluations, and adverse events were also recorded. RESULTS The rate of seizure reduction of >50% was 30.3%, 37.5%, and 34.7% for all seizure types at 3, 6, and 12 months, in which 7.6%, 8.9%, and 14.3% of the patients became seizure-free at these time points, respectively. No significant differences were found between enzyme-inducing and nonenzyme-inducing antiepileptic drugs in combination with PER with regard to the responder rate. Five patients with Dravet syndrome were included in the study. Four of them (80%) exhibited 50% seizure reduction at the last visit, at which point, two patients (40.0%) were seizure-free. The retention rate was 51% at 12 months. Adverse events were documented in 25 patients (35.7%) and led to PER discontinuation in eight patients (12.1%). The most common adverse events comprised irritability, skin rash, dizziness, and somnolence; however, all were transient and successfully managed after PER dose reduction or discontinuation. CONCLUSION The current data support the value of adjunctive PER in child and adolescent patients with pharmacoresistant epilepsy in daily clinical practice. Perampanel was efficacious and generally well-tolerated as an add-on treatment for epilepsy.

Correlation of vocals and lyrics with left temporal musicogenic epilepsy

Whether the cognitive processing of music and speech relies on shared or distinct neuronal mechanisms remains unclear. Music and language processing in the brain are right and left temporal functions, respectively. We studied patients with musicogenic epilepsy (ME) that was specifically triggered by popular songs to analyze brain hyperexcitability triggered by specific stimuli. The study included two men and one woman (all right‐handed, aged 35–55 years). The patients had sound‐triggered left temporal ME in response to popular songs with vocals, but not to instrumental, classical, or nonvocal piano solo versions of the same song. Sentimental lyrics, high‐pitched singing, specificity/familiarity, and singing in the native language were the most significant triggering factors. We found that recognition of the human voice and analysis of lyrics are important causal factors in left temporal ME and provide observational evidence that sounds with speech structure are predominantly processed in the left temporal lobe. A literature review indicated that language‐associated stimuli triggered ME in the left temporal epileptogenic zone at a nearly twofold higher rate compared with the right temporal region. Further research on ME may enhance understanding of the cognitive neuroscience of music.