Chun-Hing Yiu

Olfactory Auras in Patients with Temporal Lobe Epilepsy

Summary:  Purpose: To investigate olfactory auras in patients with temporal lobe epilepsy (TLE).

Antiepileptic Drug Withdrawal in Patients with Temporal Lobe Epilepsy Undergoing Presurgical Video-EEG Monitoring

Summary:  Purpose: To investigate antiepileptic drug (AED) withdrawal during video‐EEG monitoring in adult patients with temporal lobe epilepsy (TLE).

Magnetoencephalographic yield of interictal spikes in temporal lobe epilepsy: Comparison with scalp EEG recordings

To compare magnetoencephalography (MEG) with scalp electroencephalography (EEG) in the detection of interictal spikes in temporal lobe epilepsy (TLE), we simultaneously recorded MEG and scalp EEG with a whole-scalp neuromagnetometer in 46 TLE patients. We visually searched interictal spikes on MEG and EEG channels and classified them into three types according to their presentation on MEG alone (M-spikes), EEG alone (E-spikes), or concomitantly on both modalities (M/E-spikes). The M-spikes and M/E-spikes were localized with MEG equivalent current dipole modeling. We analyzed the relative contribution of MEG and EEG in the overall yield of spike detection and also compared M-spikes with M/E-spikes in terms of dipole locations and strengths. During the 30- to 40-min MEG recordings, interictal spikes were obtained in 36 (78.3%) of the 46 patients. Among the 36 patients, most spikes were M/E-spikes (68.3%), some were M-spikes (22.1%), and some were E-spikes (9.7%). In comparison with EEG, MEG gave better spike yield in patients with lateral TLE. Sources of M/E- and M-spikes were situated in the same anatomical regions, whereas the average dipole strength was larger for M/E- than M-spikes. In conclusion, some interictal spikes appeared selectively on either MEG or EEG channels in TLE patients although more spikes were simultaneously identified on both modalities. Thus, simultaneous MEG and EEG recordings help to enhance spike detection. Identification of M-spikes would offer important localization of irritative foci, especially in patients with lateral TLE.

A Double‐Blind, Placebo‐Controlled Study of Topiramate in Adult Patients with Refractory Partial Epilepsy

Summary: Purpose: The efficacy and safety of topiramate (TPM) as adjunctive therapy in the treatment of adult Chinese patients with refractory partial epilepsy were investigated in a randomized, double‐blind, placebo‐controlled study.

Ictal Speech Manifestations in Temporal Lobe Epilepsy: A Video‐EEG Study

Summary: To evaluate ictal speech manifestations in complex partial seizures (CPS), we reviewed videotapes of 68 consecutive patients who underwent anterior temporal lobectomy (ATL) for treatment of intractable epilepsy in Taiwan. In all, 261 CPS were collected from their video‐EEG (VEEG) recordings. Cerebral speech dominance was determined by intracarotid injection of sodium amobarbital (Wada test) in all cases. Ictal speech manifestations, classified as verbalization or vocalization, occurred in 32 patients (47.1%) with 96 seizures (36.8%). Ictal verbalization occurred in 10 patients (14.7%). Ictal vocalization was observed in 28 patients (41.2%); including 6 patients who also had ictal verbalization. Thirty‐six patients (52.9%) had no seizure with ictal speech manifestations. Ictal verbalization had significant lateralization value: 90% of patients with this manifestation had seizure focus in the nondominant temporal lobe (p = 0.049). Seizures of patients with ictal vocalization were not more likely to arise from either temporal lobe. We also observed bilingual patients who exclusively spoke in their mother tongue (Taiwanese) rather than the acquired language (Mandarin) in 72.2% of seizures with verbalization. This finding is significant and contrary to a commonly held notion that the acquired language is used in seizures associated with speech behaviors.

Medication education for patients with epilepsy in Taiwan

The aim of this study is to evaluate the medication knowledge achieved by conventional verbal education and the influence of drug information leaflets in patients with epilepsy. Drug compliance and sources of information of the patients were also examined. Fifty-one adults in an epilepsy outpatient clinic participated this survey. These patients were asked to complete a questionnaire and to specify sources of drug information. Serum drug levels were checked and compared with the self-reported compliance. Then, drug information leaflets were given to patients. In the next follow-up visit, patients were asked to fill out the same questionnaire again. In the baseline assessment, 36 patients (70.6%) could accurately list their medications. However, half of patients were not knowledgeable about side effects and did not keep a seizure diary. After provision of drug leaflets, the epilepsy medication assessment score increased from 3.9 +/- 1.9 to 5.1 +/- 1.7 (P<0.001). In addition, patients reported being compliant most of the time and this matched drug levels. On average, each patient had 2.8 sources of information and 5 patients used Internet as a tool. Despite achieving good compliance, conventional verbal education did not sufficiently cover drug-related issues. Providing patients with written information apparently increase their medication knowledge and probably enhance seizure control.

Ictal Vomiting in Partial Seizures of Temporal Lobe Origin

We report 3 cases presenting ictal vomiting during partial seizures of temporal lobe origin. Two patients had complex partial seizures accompanying vomiting characteristics. Ictal vomiting occurred early in the course of the seizure when rhythmic discharges involved predominantly the left hemispere, the language dominance hemispere. The other patient had ictal vomiting in simple partial seizures which originated from the right temporal lobe or the language nondominant side. All 3 patients underwent anterior temporal lobectomy with promising outcomes. Pathologic diagnosis included hippocampal sclerosis in 2 patients and astrocytoma in 1 patient. In our patients, ictal vomiting does not lateralize temporal lobe epilepsy and is not specific to pathology.

Prognostic value of electrocorticography findings during callosotomy in children with Lennox-Gastaut syndrome.

OBJECTIVE To analyze findings and acute changes in electrocorticograms (ECoGs) obtained during corpus callosotomy in order to identify any relationships with the postoperative outcome of seizure activity. METHODS We retrospectively analyzed ECoGs obtained during anterior callosotomy (4-6 cm) in 48 patients with Lennox-Gastaut syndrome (32 boys and 16 girls, age 1-20 years, mean age 7.6 years) who underwent surgery between July 1993 and November 1996 to correlate recording findings with postoperative seizure activity. At the time of analysis, all patients had been followed postoperatively for more than 4 years. RESULTS Of 48 patients, 31 (64.6%) had significant improvement in seizure control after surgery. In pre-excisional ECoGs, 38 (79.2%) of 48 patients had bisynchronous epileptiform discharges. Patients (23 of 33 patients, 69.7%) with significant blockage of bisynchronous discharges recorded during callosotomy achieved the best postoperative seizure outcomes, but the difference did not reach statistical significance (P>0.05). CONCLUSIONS Based on our experience, changes in ECoG during callosotomy do not predict postoperative seizure outcome. Insignificant blockage of bisynchronous epileptiform discharges in ECoGs during callosotomy does not predict a worse prognosis than that associated with significant intraoperative blockage.

Increased Intrinsic Connectivity of the Default Mode Network in Temporal Lobe Epilepsy: Evidence from Resting-State MEG Recordings

The electrophysiological signature of resting state oscillatory functional connectivity within the default mode network (DMN) during spike-free periods in temporal lobe epilepsy (TLE) remains unclear. Using magnetoencephalographic (MEG) recordings, this study investigated how the connectivity within the DMN was altered in TLE, and we examined the effect of lateralized TLE on functional connectivity. Sixteen medically intractable TLE patients and 22 controls participated in this study. Whole-scalp 306-channel MEG epochs without interictal spikes generated from both MEG and EEG data were analyzed using a minimum norm estimate (MNE) and source-based imaginary coherence analysis. With this processing, we obtained the cortical activation and functional connectivity within the DMN. The functional connectivity was increased between DMN and the right medial temporal (MT) region at the delta band and between DMN and the bilateral anterior cingulate cortex (ACC) regions at the theta band. The functional change was associated with the lateralization of TLE. The right TLE showed enhanced DMN connectivity with the right MT while the left TLE demonstrated increased DMN connectivity with the bilateral MT. There was no lateralization effect of TLE upon the DMN connectivity with ACC. These findings suggest that the resting-state functional connectivity within the DMN is reinforced in temporal lobe epilepsy during spike-free periods. Future studies are needed to examine if the altered functional connectivity can be used as a biomarker for treatment responses, cognitive dysfunction and prognosis in patients with TLE.

Magnetoencephalographic study of rhythmic mid-temporal discharges in non-epileptic and epileptic patients

To evaluate the source location and clinical significance of rhythmic mid-temporal theta discharges (RMTD) by MEG in non-epileptic and epileptic patients, we conducted simultaneous MEG and EEG recordings with a whole-scalp 306-channel neuromagnetometer in three patients: one with right temporal lobe epilepsy (TLE), one with right frontal lobe epilepsy (FLE), and one with tension headache. We visually detected the RMTD activity and interictal spikes, and then localised their generators by MEG source modelling. We repeated MEG measurement 3 months after right anterior temporal lobectomy (ATL) in the TLE patient; 3 months after anticonvulsant medication in the FLE patient. In epileptic patients, RMTD activities were found during drowsiness over the left temporal channels of both MEG and EEG recordings, and their generators were localised to the left posterior inferior temporal region. In the patient with tension headache, RMTD was localised in the right inferior temporal area. When the epileptic patients became seizure free with disappearance of epileptic spikes, RMTD was still found over the left temporal channels. Besides, some bursts of RMTD appeared also in the right temporal channels in our TLE patient after ATL. Our results indicate that the source of RMTD activity is located in the fissural cortex of the posterior inferior temporal region. As a physiologic rhythm related to dampened vigilance, RMTD has no direct relation to epileptogenic activity.