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Biomedical subjects

Yu-tze Ng

Publications and source records attributed to Yu-tze Ng.

14 recordsLinked to original sources
PubMed2007

Clobazam.

Catastrophic childhood epilepsies such as infantile spasms (IS), progressive myoclonic epilepsy, and Lennox-Gastaut syndrome (LGS) are rare but debilitating and frequently persist into adulthood. Early, targeted use of medications that have demonstrated efficacy in the management of LGS or its associated epilepsies may simplify the patient's treatment regimen and reduce the incidence of adverse events. Key to the overall benefit to the patient is to maximize seizure control while minimizing adverse effects, especially behavioral and cognitive problems. Clobazam has demonstrated clinical benefit and has been administered safely in more than 50 European studies in which data were reported on greater than 3000 pediatric and adult patients with epilepsy, 300 of whom were diagnosed with LGS; therefore, its use is now being investigated in the U.S. This review will explore the use of clobazam in the treatment of epilepsy, particularly with regard to its potential benefit in LGS. Though not currently approved for use in the U.S., a program is underway to gain Food and Drug Administration approval for the treatment of pediatric and adult patients with refractory epilepsy, specifically in LGS. A phase 2 study will be completed in late 2006 to investigate the safety and efficacy of clobazam as adjunctive therapy in 68 pediatric and adult patients with LGS.

Animals↗
PubMed2006

Transcallosal resection of hypothalamic hamartoma for intractable epilepsy.

PURPOSE: To present the results of transcallosal surgical resection of hypothalamic hamartoma (HH) in 26 patients with refractory epilepsy in a prospective outcome study. METHODS: Patients with refractory epilepsy symptomatic to HH were referred for surgical resection of their HH (mean age, 10.0 years; range, 2.1-24.2 years). A transcallosal, interforniceal approach was used to remove and/or disconnect the hamartoma. Volumetry was obtained on pre- and postoperative brain MRI scans to determine percentage of resection. Outcome assessment included determination of postoperative seizure frequencies in comparison to baseline and the incidence of postoperative complications. Postoperative changes in cognitive and behavioral functioning, in comparison to baseline, were elicited by parental report. RESULTS: The average postoperative follow-up interval was 20.3 months (range, 13-28 months). Fourteen (54%) patients were completely seizure free, and nine (35%) had at least a 90% improvement in total seizure frequency. Parents reported postoperative improvement in behavior in 23 (88%) patients and in cognition in 17 (65%) patients. Transient postoperative memory disturbance was seen in 15 (58%) patients, but persisted in only two (8%). Two (8%) patients had persisting endocrine disturbance requiring hormone replacement therapy (diabetes insipidus and hypothyroidism in one each). With univariate analysis, the likelihood of a seizure-free outcome correlated with younger age, shorter lifetime duration of epilepsy, smaller preoperative HH volume, and 100% HH resection. CONCLUSIONS: Refractory epilepsy associated with HH can be safely and effectively treated with surgical resection by a transcallosal, interforniceal approach. Short-term memory deficits appear to be transient for most patients, and family perception of the impact of surgery on cognitive and behavioral domains is favorable. Complete resection yields the best result.

Adolescent↗
PubMed2006

Childhood mesial temporal sclerosis.

The prevalence and clinical characteristics of mesial temporal sclerosis have not been well studied in children. All brain magnetic resonance imaging (MRI) reports of children less than 14 years of age were reviewed from two tertiary institutions. A 52-month period from one institution and a 37-month period from the other were reviewed. All reports of definite or possible mesial temporal sclerosis were noted. These patients' MRIs were then reviewed to confirm the MRI diagnostic criteria of mesial temporal sclerosis. The charts of the patients who satisfied these criteria were reviewed in detail. Three thousand one hundred brain MRI reports were reviewed. Twenty-six reports of mesial temporal sclerosis were found. Twenty-four of the 26 films satisfied the criteria of mesial temporal sclerosis by MRI after the films were reviewed. The prevalence among all pediatric brain MRI studies was 0.77%. All patients had presented with seizures, that is, there were no "incidental" findings of mesial temporal sclerosis. Four patients had a history of febrile seizures. Mesial temporal sclerosis is an uncommon finding in children, but when it occurs, it is always associated with epilepsy. Asymptomatic mesial temporal sclerosis or mesial temporal sclerosis not associated with a seizure disorder did not occur in our series. Febrile seizures can occur in association with mesial temporal sclerosis presenting in childhood.

Brain Diseases↗
PubMed2005

Neurologic complications associated with respiratory syncytial virus.

Encephalopathy has been demonstrated to be associated with respiratory syncytial virus bronchiolitis. In this study, the data on all patients less than 14 years of age hospitalized with respiratory syncytial virus bronchiolitis over the past 4 years was reviewed. Patients who had concomitant diagnoses consistent with neurologic disease underwent detailed chart review. There were 964 patients (age 0.1 to 13.6 years) with a diagnosis of respiratory syncytial virus bronchiolitis. Thirty-six of these patients had concurrent neurologic diagnoses. Twenty-four patients were excluded because of preexistent neurologic disorders, probable simple febrile seizures, or a history of epilepsy. Twelve respiratory syncytial virus-positive patients had definite neurologic complications without another recognized cause. Seven of these patients had seizures (predominantly generalized tonic-clonic and one with status epilepticus), three had generalized encephalopathy (marked hypotonia and decreased responsiveness) of whom two also developed esotropia. Two patients developed isolated esotropia. There was an incidence of neurologic complications of 1.2% (0.7% seizures) in a total of 964 patients with respiratory syncytial virus bronchiolitis. This percentage does not include presumed simple febrile seizures or exacerbations of preexisting seizure disorder (further 1.3%). Neurologic complications occur with respiratory syncytial virus bronchiolitis, and physicians and other caregivers should be aware of this entity as well as the favorable prognosis.

Acute Disease↗
PubMed2005

The hypothalamic hamartoma: a model of subcortical epileptogenesis and encephalopathy.

Although uncommon, the hypothalamic hamartoma (HH) is often associated with a devastating clinical syndrome, which may include refractory epilepsy, progressive cognitive decline, and deterioration in behavioral and psychiatric functioning. Contrary to conventional thinking which attributed seizure origin to cortical structures, the hamartoma itself has now been firmly established as the site of intrinsic epileptogenesis for the gelastic seizures (i.e., characterized by unusual mirth) peculiar to this disorder. It also appears that the HH contributes to a process of secondary epileptogenesis, with eventual cortical seizure onset of multiple types in some patients. Anticonvulsant medications are known to be poorly effective in this disorder. Treatment, including some innovative approaches to surgical resection, is now targeted directly at the HH itself, with impressive results. Younger patients, in particular, may avoid the deteriorating course described earlier. Access to tissue from larger numbers of patients at single or collaborating centers specializing in HH surgery will allow for research into the fundamental mechanisms producing this little understood disorder. Refractory epilepsy associated with HH is the premier human model for subcortical epilepsy and an excellent model for secondary epileptogenesis and epileptic encephalopathy.

Animals↗
PubMed2005

Emergency transcallosal resection of hypothalamic hamartoma for "status gelasticus".

Hypothalamic hamartomas are rare developmental malformations of the inferior hypothalamus. Typically they result in symptomatic, refractory mixed seizure disorder with trademark gelastic or laughing seizures. We present a 30-month-old boy with a hypothalamic hamartoma and a nearly 2-month history of near-continuous gelastic seizures, which we have labeled "status gelasticus." The seizures were refractory to multiple antiepileptic drugs (AEDs), and emergency transcallosal resection of the hypothalamic hamartoma was performed with resultant near-immediate cessation of the seizures. At 12-month follow-up, the patient was averaging one brief gelastic seizure every 2 weeks, with a longest seizure-free period of 2 months.

Child, Preschool↗
PubMed2005

Successful resection of a hypothalamic hamartoma and a Rathke cleft cyst. Case report.

The authors report the case of a 12-year-old girl with Pallister-Hall syndrome, long-standing refractory, symptomatic epilepsy, mental retardation, and panhypopituitarism in whom two rare, deep midline lesions were detected. She underwent successful transsphenoidal resection of the Rathke cleft cyst and transcallosal resection of the hypothalamic hamartoma within a 4-day period without complications. Neuropathological studies confirmed the neuroimaging diagnoses for the two lesions. The patient has been seizure free for 6 months postoperatively.

Central Nervous System Cysts↗
PubMed2004

Magnetic resonance imaging detection of mesial temporal sclerosis in children.

The objective of this study was to investigate the prevalence and clinical characteristics of mesial temporal sclerosis as diagnosed by brain magnetic resonance imaging in children. A total of 390 consecutive brain magnetic resonance imaging studies in children were reviewed for evidence of mesial temporal sclerosis. Subsequently, the magnetic resonance imaging scans and charts of patients with mesial temporal sclerosis were reviewed and their clinical details were evaluated. The magnetic resonance imaging studies had been performed for multiple indications, including seizures, headache, and developmental problems. In children, the prevalence of mesial temporal sclerosis among all brain magnetic resonance imaging studies was 3.1% (12 of 390 studies) and 12.1% (12 of 99 studies) among all brain magnetic resonance imaging studies performed for seizures. These children all presented with a history of seizure disorder, often had other medical problems, and histopathology (when available) nearly always (5 of 6 patients) confirmed their magnetic resonance imaging diagnosis of mesial temporal sclerosis. The prevalence of mesial temporal sclerosis is low among all pediatric patients who had magnetic resonance imaging brain studies. All our mesial temporal sclerosis patients had clinical seizures; i.e., it was never an "incidental finding". Children with mesial temporal sclerosis often had comorbid conditions, and the diagnosis of mesial temporal sclerosis made by magnetic resonance imaging was accurate when compared with the available histopathology.

Child↗
PubMed2004

Treatment of refractory status epilepticus with hemispherectomy.

A 7-year-old boy with left hemiparesis secondary to right hemispheric cortical dysplasia was admitted to the hospital with increasing numbers of seizures. Magnetic resonance imaging showed a small dysplastic right hemisphere with abnormally thickened gyri and an apparently normal left hemisphere. Previous video-electroencephalogram (EEG) monitoring showed bilateral independent spikes and generalized slow spike-and-wave episodes on EEG and [18F]fluorodeoxyglucose (FDG) positron emission tomography scan demonstrated scattered areas of regional hypometabolism bilaterally; therefore hemispherectomy was not undertaken at that time. During this hospital stay, nonconvulsive status epilepticus developed and was refractory to multiple medical therapies including pentobarbital (PTB) coma. Burst-suppression pattern during PTB coma appeared to be generalized spike and wave, but when EEG was reviewed with increased time resolution spikes suggested a right hemisphere origin. The patient underwent bilateral intracarotid amobarbital spike-suppression test that showed only minimal suppression of epileptiform discharges with injection of the left carotid, but complete suppression of spike activity after right-sided carotid injection. A right hemispherectomy was performed with complete cessation of status epilepticus. Postoperative EEG showed no epileptiform discharges. Patient follow-up was limited to 12 months after surgery. The patient had regained the ability to walk unaided and was seizure free with a single antiepileptic medication. This case illustrates a potentially life-saving procedure for refractory status epilepticus and several techniques including a spike-suppression test to aid in prediction of cessation of seizures after hemispherectomy.

Amobarbital↗
PubMed2004

Agenesis of the corpus callosum is associated with feeding difficulties.

Our objective was to characterize the common occurrence of feeding and swallowing disorders noticed by our speech therapy department among patients with agenesis of the corpus callosum. All patients with suspected or presumed agenesis of the corpus callosum undergoing therapy for feeding and/or swallowing disorders, including oral and/or pharyngeal dysphagia and oral-sensory disorder, were identified. Their brain magnetic resonance imaging (MRI) studies and charts were reviewed in detail. Seven patients with striking oral-motor and oral-sensory disorder met the criteria for agenesis of the corpus callosum. Particular difficulties noted include oral-sensory defensiveness in five of these seven patients, oral dysphagia/weakness in all seven patients, and pharyngeal dysphagia with risk of aspiration in three of these seven patients. The oral-motor weakness observed in all of the patients affected the strength and coordination necessary for functional oral-phase swallowing. We conclude that feeding and swallowing disorders are significant in children with agenesis of the corpus callosum. Although the pathophysiologic mechanism is not known, recognition of this phenomenon is important because early detection and intervention can facilitate functional feeding and swallowing patterns earlier in these patients, therefore avoiding the adverse and more severe disorders that can arise when dysphagias and/or oral-sensory disorder persist over extended periods of time.

Agenesis of Corpus Callosum↗
PubMed2003

Successful neurosurgical treatment of childhood complex partial status epilepticus with focal resection.

The treatment of complex partial status epilepticus continues to be controversial, especially with regard to the intensity of the treatment. Medical therapy and drug-induced coma are sometimes required. Rarely this may not be effective. A healthy 4-year old girl was first seen in complex partial status epilepticus. She had a 1-year history of cryptogenic partial-onset seizures. Detailed magnetic resonance imaging (MRI) studies were normal. Her course was refractory to multiple medical therapies and multiple subpial transection (MST). An urgent epilepsy surgery evaluation resulted in a focal cortical resection being performed over the right mesial parietal region with resultant seizure freedom and no significant neurologic deficit 2 years later. This patient illustrates the need to consider occult focal cortical dysplasia as a cause of nonconvulsive status epilepticus (NCSE) in children, and if it is not responsive to medical management, the utility of performing an urgent epilepsy surgery evaluation.

Brain Mapping↗
PubMed2002

Lumbar spinal stenosis causing congenital clubfoot.

Congenital lumbar spinal stenosis is believed to rarely cause neurologic symptoms during childhood. We present a 16-year-old boy with bilateral congenital clubfeet surgically corrected by tendo Achillis releases at 2 years of age who presented with progressive, bilateral footdrop. Magnetic resonance imaging of his lumbosacral spine showed severe spinal stenosis at the L3-5 vertebrae. Congenital lumbar spinal stenosis is probably an under-recognized cause of lower extremity neurologic abnormalities, including clubfoot deformity. Magnetic resonance imaging has made this eminently treatable disorder easier to recognize.

Adolescent↗
PubMed2002

Levetiracetam in refractory pediatric epilepsy.

Levetiracetam, one of the newer-generation antiepilepsy drugs, is not currently approved for use in children. Given its favorable efficacy, pharmacokinetic, and, particularly, safety profile in adults, we felt that it may be a useful antiepilepsy drug for children with refractory epilepsy. We treated 39 patients (mean age 8.6 years) with open-label levetiracetam for up to 9 months. Seizure frequency, drug dosages, adverse events, and neurologic examinations were documented at baseline and routine follow-up visits. Levetiracetam, as add-on therapy, was effective in reducing seizure frequency in a variety of seizure types but was most effective for partial-onset seizures. Fourteen patients were discontinued for lack of efficacy or adverse events. Ten patients reported improvements in cognition or behavior. Levetiracetam was generally effective and well tolerated in this open-label study. Its apparent positive effects on cognition in some patients are encouraging. Large, well-controlled studies are needed to fully define levetiracetam's potential in children with refractory epilepsy.

Adolescent↗