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Biomedical subjects

W D Shields

Publications and source records attributed to W D Shields.

At least 37 records · Page 2Linked to original sources
PubMed1998

Blink rate in pediatric complex partial seizure disorder.

This study examined spontaneous blink rate, a putative measure of dopamine function, in 30 children with complex partial epilepsy and 61 normal children. The children with epilepsy had significantly lower blink rates than the normal children in a conversation and a verbal recall task, particularly if they had a schizophrenia-like psychosis, EEG evidence for left focal epileptic activity, illogical thinking, discourse deficits, and distractibility. They modulated their blink rates across a listening, a conversation, and a verbal recall task like the normal children. Given previously reported low blink rates in schizophrenic children, these findings suggest that children with complex partial epilepsy or schizophrenia might have similar biological features.

Analysis of Variance↗
PubMed1997

Vigabatrin.

Vigabatrin is a structural analogue of gamma amino butyric acid (GABA), which binds irreversibly to GABA-transaminase causing increased brain levels of GABA. It is an important advance in the medical management of children with epilepsy. It appears to be particularly effective in the treatment of infantile spasms, especially when caused by tuberous sclerosis. It is also effective in the treatment of partial seizures and some generalized seizures including those of the Lennox-Gastaut syndrome. However, myoclonic seizures may be made worse by vigabatrin. It is not yet approved for use in the United States but it is approved throughout most of the rest of the world including Canada and Mexico. Release in the United States is expected in the near future.

Animals↗
PubMed1997

Formal thought disorder and psychopathology in pediatric primary generalized and complex partial epilepsy.

OBJECTIVE: To examine whether formal thought disorder and psychopathology occurred in children with complex partial seizures (CPS) rather than children with primary generalized epilepsy with absences (PGE) or nonepileptic children. METHOD: Formal thought disorder was coded in 30 children with CPS, 24 children with PGE, and 61 nonepileptic children, and structured interview-based psychiatric diagnoses were obtained for the epileptic subjects. RESULTS: The CPS subjects had significantly more illogical thinking than the PGE and nonepileptic children. The severity of their illogical thinking was related to global cognitive dysfunction and a schizophrenia-like psychosis. Age of onset and seizure control, however, were significantly associated with the severity of illogical thinking in the PGE group. One or more psychiatric diagnoses were found in 63% of the CPS and 54% of the PGE patients, particularly if they had global cognitive deficits. CONCLUSION: Illogical thinking, associated with cognitive dysfunction or schizophrenia-like symptoms, might be a feature of pediatric CPS. Psychopathology might be related to global cognitive dysfunction in pediatric CPS and PGE.

Adolescent↗
PubMed1997

Developmental outcomes in children receiving resection surgery for medically intractable infantile spasms.

Two-year postsurgical developmental outcomes were assessed in 24 children with infantile spasms who underwent resective surgery. The mean age of onset of infantile spasms was 12.0 weeks and the mean age at surgery was 20.8 months. Developmental outcomes were assessed using the Vineland Adaptive Behavior Scales (VABS). There was a significant increase in developmental level at 2 years postsurgery compared with presurgical levels. At 2 years postsurgery only one of the children in this series was severely retarded. The developmental outcomes of patients in the series were better than those in prior studies of symptomatic patients receiving medical treatment for infantile spasms. It is surprising that the children in the UCLA series frequently had developmental outcomes equal to and sometimes superior to other groups of children with infantile spasms, since all the UCLA patients were symptomatic, had neurologic deficits and had failed to respond to adrenocorticotrophic hormone (ACTH) and antiepileptic drugs. The 2-year postsurgery developmental outcomes were best for the children who received surgery when they were relatively young and who had the highest level of developmental attainments presurgically.

Activities of Daily Living↗
PubMed1996

Hemispherectomy for intractable seizures in children: a report of 58 cases.

Fifty-eight children who underwent anatomical, functional, or modified anatomical hemispherectomy for intractable seizures from 1986 to 1995 were evaluated for seizure control, motor function, and complications. Age at surgery ranged from 0.3 to 17.3 years (median 2.8 years). Twenty-seven anatomical, 27 functional, and 4 modified anatomical hemispherectomies were performed. Seizure control and motor function in the 50 patients with more than 1 year follow-up revealed a 90% or better reduction in seizure frequency in 44/50 (88%) overall: 19/22 (86%) anatomical, 23/26 (89%) functional, and 2/2 modified anatomical. Motor function of the preoperatively hemiparetic extremities was improved or unchanged postoperatively in 38/50 (76%) of the patients. Complications included one intraoperative death, one late death from shunt obstruction managed elsewhere, late postoperative seizure breakthrough requiring reoperation and further disconnection in 5/27 functional hemispherectomy patients, mild cerebrospinal fluid infections in 3/27 anatomical hemispherectomy patients, and hydrocephalus requiring shunting in 3/27 functional hemispherectomy patients. A review of the literature and comparison of techniques is presented.

Adolescent↗
PubMed1996

Risk factors of infantile spasms compared with other seizures in children under 2 years of age.

To analyze the magnitude of the risk factors for infantile spasms, we evaluated the records of 80 children with infantile spasms, 474 children with other types of epilepsy, 2,196 children with febrile seizures, and 262 children with CNS infections. There was a family history of seizures in 13.8% of children with infaNtile spasms, 28.5% of children with other forms of epilepsy, 25.5% of children with febrile seizures, and 5.3% of children with CNS infections. Children with a family history of seizures were 2.82 times more likely to have infantile spasms, 7.05 time more likely to have other epilepsy, and 6.08 time more likely to have febrile seizures than controls (children with CNS infections). However, a family history of seizures increased the risk for infantile spasms only in the cryptogenic group. Children with infantile spasms were significantly more likely to have cerebral palsy, microcephaly, hydrocephaly, CNS malformations, neonatal hypoxia, or neonatal seizures than children with other types of epilepsy, febrile seizures, or CNS infections. There was a modest genetic predisposition to seizures in children with infantile spasms. However, our data suggest a much stronger association with underlying neurologic abnormalities, mainly neonatal seizures, neonatal hypoxia, and CNS malformations.

Age Factors↗
PubMed1995

Risk factors of respiratory failure in children with Guillain-Barré syndrome.

Recently it was found that plasmapheresis and intravenous immunoglobulins are effective in treating patients with Guillain-Barré syndrome (GBS). However, these treatments are expensive and not without possible adverse effects. Because signs and symptoms predictive for respiratory failure in GBS would be helpful in targeting the treatment, risk factors for respiratory failure were evaluated in 120 children with GBS. Twenty children required assisted ventilation. None of the children without any of the following risk factors had respiratory failure. If the symptoms of GBS began within 8 days after a preceding infection, the odds ratio (OR) for respiratory failure was 4.9 [95% confidence intervals (CI): 1.3-18.5]. Cranial nerve involvement was more common in children who required assisted ventilation (15/20 versus 32/100, OR: 6.4, 95% CI: 2.1-19.1). A cerebrospinal protein level > 800 mg/L during the first week had an OR for assisted ventilation of 3.1 (95% CI of OR: 1.04-9.0). In the logistic multivariate model, all of these risk factors were associated with the need for assisted ventilation. On the basis of our findings, preventive treatment with either plasmapheresis or intravenous immunoglobulins could be directed to those children with any of the risk factors; for those patients without the risk factors, clinical monitoring would be satisfactory.

Child↗
PubMed1994

Epidemiology of Guillain-Barré syndrome in children: relationship of oral polio vaccine administration to occurrence.

Because a cluster of cases of Guillain-Barré syndrome followed a mass vaccination program using oral polio vaccine, a retrospective epidemiologic survey was carried out in southern California to examine the relationship between oral polio vaccine and Guillain-Barré syndrome. We also examined the yearly pattern of Guillain-Barré syndrome and compared rates of illness in different ethnic populations. The mean annual incidence of Guillain-Barré syndrome was 0.60 (95% confidence intervals 0.48 to 0.73) per 100,000 children under 15 years of age. There was no difference in incidence between boys and girls or between ethnic populations. The incidence was significantly higher in 2-year-old children than in any other age group (p < 0.05). The onset of Guillain-Barré syndrome was preceded by an infection in 71 (76%) of 93 children. In five children (5%) a vaccination was given within 8 weeks before illness onset. Only two children received the oral polio vaccine; the duration from vaccine administration to the onset of Guillain-Barré syndrome was 41 and 52 days, whereas the mean incubation time associated with infectious illnesses was 10.3 days. Strong evidence against a causal relationship between oral polio vaccine administration and Guillain-Barré syndrome is provided by the failure to find a correlation between the usual age of immunization with oral polio vaccine and the incidence of Guillain-Barré syndrome by age and the failure to find any children with onset of Guillain-Barré syndrome within 1 month of immunization with oral polio vaccine.

Adolescent↗
PubMed1994

Investigational antiepileptic drugs for the treatment of childhood seizure disorders: a review of efficacy and safety.

Pediatric epileptology is very different from adult epileptology. Although some epileptic disorders occur in both children and adults (e.g., localization-related epilepsy with complex partial seizures and primary generalized epilepsy with tonic-clonic seizures), other disorders can be called the catastrophic epilepsies of childhood (e.g., infantile spasms and the Lennox-Gastaut syndrome). They occur, or at least begin, exclusively in childhood and are often associated with mental retardation. Many of these pediatric disorders are notoriously unresponsive to currently available antiepileptic drugs (AEDs). Although there are undoubtedly many reasons for this, one possible explanation is that the methods used to screen potential AEDs use animal models of adult epilepsy. No screening program uses an animal model of seizures that begin during development and lead to functional decline.

Anti-Anxiety Agents↗
PubMed1993

Pertussis immunization and characteristics related to first seizures in infants and children.

In a previous study in which we examined the relationship of pertussis immunization to the onset of neurologic disorders during 1967 and 1968 and during 1972 and 1973 in Denmark, there were 554 children with initial onset of epilepsy and 2158 children with first febrile convulsions. In the study population there were 112 children with epilepsy and 229 children with febrile convulsions for whom the exact date of pertussis immunization and the exact date of the onset of illness were known. We analyzed selected clinical variables by specific time intervals between pertussis immunization and the first seizure. In the children with epilepsy, no relationship was found between time of pertussis immunization and the specific variables that were examined. In contrast, the following characteristics in children with febrile seizures were significantly more common when pertussis immunization had occurred within 3 days, compared with more than 7 days of the event: first seizure more than 10 minutes in duration, the occurrence of more than one seizure, the longest seizure (when there was more than one) more than 10 minutes in duration, and the occurrence of a seizure described as focal. The lack of specific characteristics in epilepsy that had its onset in a temporal relationship to pertussis immunization is further evidence that pertussis vaccine does not cause this disorder. The cause of increased severity of febrile seizures apparently associated with pertussis immunization is unknown.

Humans↗
PubMed1993

Communication deficits in children undergoing temporal lobectomy.

OBJECTIVE: To examine formal thought disorder and discourse (cohesive) devices that make speech coherent prospectively in seven children, aged 5.7 to 16.7 years, before and after temporal lobectomy for intractable cut points determined from sensitivity and specificity analyses of formal thought disorder and discourse measures in 22 children with complex partial seizure disorder and 45 normal children. RESULTS: Before surgery, the mean illogical thinking and discourse scores of the surgical candidates were in the pathological range. After a mean postoperative follow-up period of 15.1 months, their illogical thinking (but not their discourse scores) decreased significantly to the normal range. CONCLUSIONS: These preliminary findings are discussed in terms of the possible role of postsurgical changes in seizure control, behavior, antiepileptic drugs, cognition, and prefrontal function.

Adolescent↗
PubMed1993

Surgery for epilepsy. Special pediatric considerations.

Children with epilepsy require special consideration because the nature of their seizures is different from those in adults, the effects of intractable epilepsy may be more serious in children, and younger children may have greater potential for recovery than adults. This article reviews the unique problems and approaches to resective surgery for pediatric epilepsy.

Age Factors↗
PubMed1992

Neuropathologic findings in cortical resections (including hemispherectomies) performed for the treatment of intractable childhood epilepsy.

Despite the use of hemispherectomy in the treatment of medically refractory seizures since the early 1950's, few studies published have documented neuropathologic findings in the resected specimens. This report describes the neuropathologic findings in 38 children who underwent either hemispherectomy or multilobar cortical resection as treatment for medically intractable epilepsy between 1986 and 1990. Examination of the resected specimens revealed a variety of abnormalities which fell into four broad categories. Malformations or hamartomatous lesions were the dominant finding in 15 patients, whereas encephalomalacic lesions were the most prominent abnormality in 16; chronic pathogen-free encephalitits (Rasmussen's encephalitis) was present in 3 and an additional 3 children had Sturge-Weber-Dimitri syndrome. There were no gross or microscopic abnormalities in 1 patient. This report provides the first comprehensive description of the pathologic findings in a series of children with refractory epilepsy of varying types treated by hemispherectomy-multilobar resection.

Brain Ischemia↗
PubMed1992

Morphological substrates of infantile spasms: studies based on surgically resected cerebral tissue.

Extensive surgical resections of neocortical cerebral tissue (including hemispherectomies) from 13 infants and children with infantile spasms showed that 12 of 13 specimens contained either malformative and dysplastic lesions of the cortex and white matter (sometimes with associated hamartomatous proliferation of globular cells), or destructive lesions possibly acquired as a result of anoxic-ischemic injury, or a combination of the two. In brain tissue from 4 patients, coarse neuronal cytoplasmic fibrils resembling neurofibrillary tangles were seen in areas of dysplastic brain on silver-stained (Bielschowsky technique) sections. Immunohistochemical (immunoperoxidase) study of cortical lesions containing globular cells employing primary antibodies to glial fibrillary acidic protein and synaptophysin as markers of astrocytic and neuronal differentiation, respectively, revealed that many cells showed astrocytic and/or neuronal features, suggesting the local proliferation of primitive or multipotential neuroectodermal cells as one substrate for this seizure disorder. Morphological abnormalities of a severe degree and wide extent in the resected tissue (e.g., in one patient with hemimegalencephaly) often showed features to suggest that they may represent variants of tuberous sclerosis. These most likely result from abnormal movement and/or local proliferation of neuroectodermal precursors that have migrated from the germinal matrix to the cortical mantle. Cellular, molecular and neurophysiological study of these abnormalities is likely to yield information about basic molecular mechanisms of brain malformation and injury important in the pathogenesis of infantile spasms and other forms of focal or generalized epilepsy.

Cerebral Cortex↗
PubMed1992

Formal thought disorder in pediatric complex partial seizure disorder.

We compared the formal thought disorder ratings of 27 children with complex partial seizure disorder, 31 schizophrenic children and 58 normal children. The epileptic children with fullscale IQ scores below 100 had significantly more formal thought disorder than normal children with a similar IQ. The severity of their formal thought disorder was related to the age of seizure onset, seizure control and a diagnosis of schizophrenia spectrum disorder. The schizophrenic children had thought disorder irrespective of IQ scores. The cognitive correlates of their formal thought disorder scores differed from those of the epileptic children. Possible anatomical substrates of thought disorder in childhood complex partial seizure disorder and schizophrenia are discussed.

Attention↗
PubMed1992

Treatment of infantile spasms: medical or surgical?

Although infantile spasms were initially described in 1841, remarkably little progress has been made in understanding the pathophysiology of this "peculiar form of infantile convulsions." Consequently, our ability to treat infantile spasms is limited. Infantile spasms are classified as a "generalized" seizure disorder in the international classification system, which suggests that the underlying brain abnormality causing the seizures also must be diffuse or generalized. As the classification suggests, there are many diffuse, or multifocal, brain disorders related to infantile spasms, e.g., inborn errors of metabolism, hypoxic-ischemic brain injury, and developmental brain defects such as tuberous sclerosis or Aicardi's syndrome. On the other hand, infantile spasms have been reported in which a localized brain abnormality was present, e.g., tumor, stroke, and trauma. On rare occasions, removal of a tumor has resulted in cessation of the generalized infantile spasms. This finding suggests that focal cortical abnormalities can cause infantile spasms and that removing the abnormality can stop the seizures. At University of California, Los Angeles, the Pediatric Epilepsy Surgery Program has developed new approaches to the treatment of infantile spasms. The principal underlying concepts are (a) children with medically refractory infantile spasms may have an area of cortical defect (called the zone of cortical abnormality) that causes the seizures and (b) infantile spasms are usually generalized seizures. Thus, the goal of the surgical assessment is not the identification of the focus of seizure onset but rather the identification of the zone of cortical abnormality.

Adrenocorticotropic Hormone↗
PubMed1992

Temporal and extended temporal resections for the treatment of intractable seizures in early childhood.

In our series of 33 children who underwent temporal and extended temporal lobe resections because of seizures, the average age at surgery was 7 years, 11 months. Sixteen cases (48%) were diagnosed as having tumors: low-grade astrocytoma (6), hamartoma (5), and ganglioglioma/neuroma (5). Other pathologic diagnoses included one or more cytoarchitectural abnormalities and/or reactive changes. Due to a more aggressive and early radiologic and electrophysiologic investigation of children with seizures, a resectable focus, e.g. neoplasm or structural abnormality, was found in a much younger age group of patients than previously reported. In children who had intractable seizures but normal radiologic studies, positron emission tomography was of great value in localizing the seizure focus. In a group of children with infantile spasms, seizures were controlled following the identification and resection of a focal lesion. Prompt detection and precise localization of lesions in the temporal lobe in the pediatric population may lead to surgical management and seizure control.

Adolescent↗