Biomedical subjects

C H Yiu

Publications and source records attributed to C H Yiu.

10 recordsLinked to original sources

PubMed1997

Unusual electroencephalographic findings in subacute sclerosing panencephalitis: a case report.

Subacute sclerosing panencephalitis (SSPE) is a rare infectious central nervous system (CNS) disease with a poor prognosis. We reported on the case of an adolescent girl with SSPE and characteristic periodic electroencephalographic (EEG) complexes. Her neurological deficits including generalized myoclonic seizures improved after intraventricular interferon (IFN) treatment. However, unusual EEG patterns consisting of bisynchronous occipital spikes preceding periodic complexes developed in follow-up EEGs.

Adolescent↗

PubMed1997

Relationship between mesial temporal seizure focus and elevated serum prolactin in temporal lobe epilepsy.

We evaluated the relationship between mesial temporal seizure focus and serum prolactin (PRL) in patients before and after they underwent anterior temporal lobectomy (ATL) for medically intractable temporal lobe epilepsy (TLE). These patients had a confirmed unilateral epileptogenic focus in mesial temporal structures, a postictal rise in serum PRL 15 to 20 minutes after onset of complex partial seizures, and were refractory for more than 2 years to antiepileptic drugs. Presurgical interictal serum PRL levels were significantly elevated (16.47 +/- 0.85 ng/mL, n = 62) and declined after ATL to normal values (patients, 9.63 +/- 0.55 ng/mL, n = 54; normal subjects, 8.99 +/- 0.57 ng/mL, n = 52). Serial evaluations indicated that normalization was seen 3 months after surgery (9.42 +/- 1.22 ng/mL, n = 9). The postsurgical reduction in serum PRL was similar in men and women, in patients with epileptogenic focus on either side of mesial temporal structures, and was unaffected by antiepileptic medication. We conclude that PRL is elevated following seizures and that a seizure focus in mesial temporal structures may exert a sustained excitatory influence on PRL release in patients with medically intractable TLE.

Adolescent↗

PubMed1997

Lamotrigine as add-on therapy in adult patients with refractory epilepsy.

BACKGROUND: Lamotrigine (LTG), one of the newly developed antiepileptic drugs, is efficacious in treating both partial and generalized seizure disorders including Lennox-Gastaut syndrome. Its effect as an add-on therapy was evaluated in 41 adult Chinese patients with refractory epilepsy. Five of the patients were Lennox-Gastaut syndrome and 36 patients had partial epilepsy. METHODS: We started LTG at 25 mg or 50 mg per day, respectively, depending on whether the patients were simultaneously taking valproate (VPA) or not. Then, LTG was increased in steps to maximal dosage (200 mg or 400 mg per day) within seven weeks and maintained for three months while pre-existing antiepileptic drugs remained unchanged. The efficacy of LTG therapy was assessed by the reduction in the overall seizure frequency. Hematological and biochemical parameters were checked before and after the trial in all patients. RESULTS: In all, 38 patients completed the trial. Twenty-two patients (57.9%) had > or = 50% reduction in seizure frequency, including four patients with Lennox-Gastaut syndrome and 18 patients with partial seizures. Among the patients with partial epilepsy, there was no significant difference in the efficacy of LTG whether the seizures were of temporal or extra-temporal origin (p = 0.577). In addition, the efficacy was not determined by the concomitant use of VPA (p = 0.189). Thirteen patients (31.7%) complained of adverse experiences, usually mild and dose-dependent. LTG had to be discontinued in only two patients (4.9%) due to severe side effects. The change in blood cell counts and biochemistry profiles was not significant in any of the patients. CONCLUSIONS: We conclude that LTG is an efficacious and safe antiepileptic drug for add-on therapy in adult patients with refractory epilepsy.

Adolescent↗

PubMed1997

Role of foramen ovale electrodes in presurgical evaluation of intractable complex partial seizures.

BACKGROUND: The value of intracranial electrodes such as depth electrodes and subdural grids for intracranial electroencephalographic (EEG) recording in patients with intractable epilepsies has been well recognized. A new technique, foramen ovale electrode (FOE) implantation, was first introduced by Wieser in 1984 for the lateralization of bilateral mesiotemporal lobe (MTL) onset of seizures. METHODS: Since October 1993, a multipolar, three-contact FOE has been used in 12 intractable epileptic patients for presurgical evaluation. The reasons for FOE implantation included bilateral MTL onset of seizures recorded by extracranial EEGs in nine patients, and extracranial EEG abnormalities inconsistent with the results of magnetic resonance imaging (MRI), positron emission tomogram (PET) or Wada test in three patients. Under general anesthesia, the FOEs were implanted according to the technique introduced by Kirschner, using Barters landmarks. RESULTS: After long-term telemetry recording with FOE, seven patients revealed clear onset of seizures originating from one side of the MTL and underwent anterior temporal lobectomy (ATL). Two patients had seizures of bilateral MTL onset. However, they received ATL due to predominantly unilateral interictal epileptiform discharges (EDs) and/or MRI and PET abnormalities. Seven (78%) of the nine operated patients became seizure-free after ATL. Three patients were considered not operable because two had multifocal onset of seizures and one had seizures with independent bilateral MTL onset. No serious complication resulted from implantation of FOE in this series. CONCLUSIONS: The semi-invasive technique of FOE is reliable for lateralization of bilateral MTL onset of seizures which are often not clearly recorded by extracranial EEGs. This procedure is safe and can be an alternative to invasive implantation of depth electrodes and subdural grids.

Adult↗

PubMed1996

Ictal speech manifestations in temporal lobe epilepsy: a video-EEG study.

To evaluate ictal speech manifestations in complex partial seizures (C PS), 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.

Adolescent↗

PubMed1995

Hypothalamic hamartoma and gelastic epilepsy: a case report.

We studied a 6-year-old girl who presented with inappropriate and uncontrollable laughing episodes since age 3. Physical examination revealed a precocious puberty. The luteinizing hormone-releasing hormone (LH-RH) stimulation test showed an increased level of follicle-stimulating hormone (FSH). The interictal electroencephalogram (EEG) was normal. Several laughing fits were documented during video/EEG monitoring. During laughing, the ictal EEG showed a diffuse suppression of background rhythm, prominent over the left mesial temporal region. A mass lesion about 2 x 2 cm in size was found over the suprasellar cistern with a broad base attached to the hypothalamus, which was isodense on a computed tomography (CT) scan, isointense to gray matter on T1-weighted magnetic resonance (MR) imaging and hyperintense on T2-weighted MR imaging. The findings were suggestive of a hypothalamic hamartoma. A variety of anticonvulsants had been used with little or no response to the frequency or duration of the laughing seizures.

Child↗

PubMed1995

Startle epilepsy presenting as drop attacks: a case report.

A case of startle epilepsy, induced by an unexpected touch on the left shoulder of a 3.5 year old boy, was investigated. The startle epilepsy manifested as an atonic drop attack. Neurological examination revealed a mild hemiparesis on the left side. Computed tomography (CT) scanning demonstrated an enhancement over the right parieto-frontal region, suggesting a hemangioma. Interictal electroencephalography (EEG) showed diffuse slowing and asymmetry of background activities with lower amplitude over the right centro-parieto-temporal region. The ictal EEG showed a paroxysmal bilaterally synchronized high amplitude single spike followed by a few slow waves lasting about one second over the bilateral centro-parieto-temporal regions. The seizure resisted anticonvulsant therapy and no significant responses were observed despite the use of combined therapy with valproic acid, phenytoin, primidone and clonazepam.

Child, Preschool↗

PubMed1994

Frequency and characteristics of early seizures in Chinese acute stroke.

We retrospectively studied 1200 hospitalized acute strokes of all etiologies between July 1990 and August 1992. Ninety-six % of all strokes underwent computed tomography of the head. Fifty-eight percent of the 1200 strokes were brain infarction, 32% brain hemorrhage, 6% subarachnoid hemorrhage and 4% were other stroke subtypes. Thirty (2.5%) of all strokes suffered from early seizures. The incidences of early seizures were 2.8% in brain hemorrhage, 2.3% in brain infarction, 2.7% in subarachnoid hemorrhage and 2% in other stroke subtypes. Early seizures were documented in 6% of the patients with carotid territory cortical infarctions and 12% of the patients with lobar hemorrhage, whereas only 0.6% of the patients without carotid territory cortical infarctions and 0.6% of the patients without lobar hemorrhage were affected. Sixty-six percent of 30 early seizures were partial seizures, 24% generalized and status epilepticus were seen only in 10%. In conclusion, we found the early seizure incidence was 2.5% in Chinese patients hospitalized with acute strokes. There was no correlation between seizure occurrence and stroke subtypes. Early seizure developed significantly higher in acute stroke patients with lesions of the cortex than those patients without cortical involvement. The partial seizures were the most frequent type occurring in 66% of all acute stroke patients with early seizures.

Acute Disease↗

PubMed1994

Temporal lobectomy in adults with intractable epilepsy.

We report on 30 adult patients with intractable complex partial seizure (CPS) of the temporal lobe origin who received anterior temporal lobectomy. The average follow-up period was 41 months. The age of onset was younger and the duration of epilepsy was longer in the non-mass lesion group than in the mass lesion group. Postoperatively, 21 patients (70%) were seizure-free, four patients (13%) had only rare seizures (less than three attacks per year), three patients (10%) achieved a remarkable reduction (more than 50%) of seizure frequency, and two patients (7%) showed no worthwhile improvement. Based on our experience, anterior temporal lobectomy is an effective and safe procedure for adult patients with intractable CPS. For diagnosis, magnetic resonance imaging (MRI) yielded a higher sensitivity rate than computed tomography (CT), especially in the group without mass lesions. Positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) was superior to single photon emission computed tomography (SPECT) which had a relatively high false localization rate. With high resolution MRI and FDG-PET, localization of the epileptogenic zone was more accurate. A preresection electrocorticogram (ECoG) was used to confirm the epileptogenic focus during the operation. The residual spikes on the postresection ECoG did not necessarily predict a poor seizure control outcome after anterior temporal lobectomy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

Carbamazepine drug interactions: the influence of concurrent drug therapy on serum concentrations of carbamazepine and its epoxide metabolite.

The influence of concurrent drug therapy (phenytoin, valproate, phenobarbital, primidone) on serum concentrations of total and free carbamazepine (CBZ) and its active metabolite carbamazepine-10, 11-epoxide (CBZ-E) in 135 epileptic patients was studied. Serum CBZ and CBZ-E levels were analyzed by high performance liquid chromatography, whereas serum levels of the anticonvulsants were determined by fluorescence polarization immunoassay. Ultrafiltration was used to separate the free drugs from the protein-bound drugs in serum. Patients were divided into five groups according to the medication they received. Linear regression analyses revealed that concurrent drug therapy affected the metabolic rate of CBZ and CBZ-E in various ways. In patients on CBZ monotherapy, 78.3% of CBZ and 52.4% of CBZ-E were bound to plasma proteins. The total serum CBZ and CBZ-E concentrations significantly correlated with their respective free levels in serum. Compared with the CBZ monotherapy group, patients receiving concurrent drug therapy showed higher CBZ clearance and had elevated CBZ-E/CBZ ratios. Although the decrease in the total CBZ concentration depended on the simultaneous phenytoin and valproate concentrations (p less than 0.05), the serum levels of phenobarbital and primidone appeared to have no significant influence on the CBZ concentration. Since great interindividual variations were found in the serum concentration after a given dose, routine monitoring of the CBZ and CBZ-E serum concentrations is essential in designing a safe and effective therapeutic regimen for epileptic patients, especially for those on polytherapy.

Adolescent↗