Biomedical subjects

A M Bye

Publications and source records attributed to A M Bye.

At least 19 recordsLinked to original sources

PubMed2001

The health-related quality of life of children with refractory epilepsy: a comparison of those with and without intellectual disability.

PURPOSE: To determine whether refractory epilepsy affects the health-related quality of life (HRQOL) of children with or without intellectual disability (ID), and if the presence of ID independently compromises HRQOL in children with refractory epilepsy. METHODS: Subjects were parents of children with refractory epilepsy, whose syndrome had been defined using ILAE (International League Against Epilepsy) criteria and video-EEG monitoring. Children had the presence or absence of ID determined by formal neuropsychological or educational assessment. The relative effect of epilepsy on the two intellectual ability groups was determined using relevant clinical variables. Parents completed a valid epilepsy-specific HRQOL questionnaire for children, the Quality of Life in Childhood Epilepsy Questionnaire (QOLCE), and, depending on intellectual ability level, the Child Behaviour Checklist or Developmental Behaviour Checklist. RESULTS: Both intellectually normal children with epilepsy and children with epilepsy and ID were more likely to have psychosocial problems compared with their respective intellectual ability reference populations. The results also revealed that children with ID had reduced HRQOL compared with intellectually normal children; a result independent of epilepsy. Analysis of the relationship between epilepsy variables and HRQOL revealed that the QOLCE was the most sensitive in detecting variation in age at onset, seizure frequency, and medications taken. CONCLUSIONS: The HRQOL of children with refractory epilepsy is greatly affected, regardless of intellectual ability level. The presence of ID in children with epilepsy independently depresses HRQOL outcomes. Compared with two generic HRQOL measures, the QOLCE was the most sensitive measure to variation in epilepsy variables.

Adolescent↗

PubMed2000

Evaluation of SPECT in the assessment and treatment of intractable childhood epilepsy.

The authors retrospectively examined the role of SPECT in 65 children undergoing video-EEG telemetry. SPECT was concordant in most children whose lesions were already localized by MRI and epilepsy syndrome and provided localizing data in more than half not localized by these modalities. Ictal SPECT provided no additional prognostic benefit in patients undergoing epilepsy surgery (n = 23) who have a localized MRI lesion. In patients without lesions, however, ictal SPECT provides useful additional localization that may be used as a guide to intracranial implantation.

Brain↗

PubMed2000

Paroxysmal non-epileptic events in children: a retrospective study over a period of 10 years.

OBJECTIVE: To determine the frequency, nature and clinical characteristics of paroxysmal non-epileptic events in children diagnosed by video electroencephalogram (EEG) monitoring at a tertiary referral centre. METHODOLOGY: A retrospective study of children with paroxysmal non-epileptic events, aged 2 weeks to 17 years inclusive was undertaken. The study group consisted of children who had video EEG monitoring during a 10-year period (1988-99). Telemetry files, medical charts, events recorded on video and record sheets were reviewed. RESULTS: A total of 666 children were analysed, 269 had epileptic events recorded, 285 had non-epileptic events and 112 had no events recorded. In children with non-epileptic events, 43% were developmentally delayed, 25% had an abnormal neurological examination and 40% had epilepsy. In the study sample an epileptiform interictal EEG was common (24%). The major subgroups of non-epileptic events were: staring (34%), sleep phenomena - benign sleep myoclonus (15%), arousals (13%), motor tics (11%) and shuddering (7%). Developmental delay (57%) was common in children who presented with staring spells. A diagnosis of a specific non-epileptic event was reached in 96% of cases. CONCLUSION: Paroxysmal non-epileptic events can cause diagnostic confusion, particularly in children with developmental delay, epilepsy or an epileptiform EEG. Accurate diagnosis can be reached in the majority of cases using video EEG monitoring.

Adolescent↗

PubMed2000

Predictors of hippocampal, cerebral, and cerebellar volume reduction in childhood epilepsy.

PURPOSE: We examined the factors related to brain volume reduction in a pediatric sample of patients that included those with nonintractable epilepsy. METHODS: Entry criteria were children less than 18 years old with epilepsy referred for MRI, including a whole brain volumetric sequence. The sample size was 231. Risk factors were ascertained from interviews and reviews of medical records. Factors included age of onset, seizure years, family history, status epilepticus, intellectual disability, and febrile convulsions. MRI data were obtained for 44 normal childhood control subjects. RESULTS: Cerebral and cerebellar volumes were significantly associated with age, gender, moderate-to-severe intellectual disability (p < 0.001), seizure years, and status epilepticus (p < 0.03). Compared with controls, the brain volume of all patients was reduced by 10% (p < 0.001). Hippocampal volume was significantly associated with total brain volume, age (p < 0.001), focal cerebral ischemic injury, and complex febrile convulsions (p < 0.05). CONCLUSIONS: Significant brain volume reduction is present in children with epilepsy. A component of this reduction is due to acquired insults. The reduction is seen even in children with infrequent seizures over a brief time, suggesting an innate structural abnormality. When evaluating possible etiologic factors in the development of hippocampal volume reduction, one must control for total brain volume. We have confirmed the association of complex febrile convulsions with unilateral hippocampal volume reduction.

Adolescent↗

PubMed2000

Cerebral and cerebellar volume reduction in children with intractable epilepsy.

PURPOSE: Adult epilepsy studies have demonstrated cerebral and cerebellar volume reduction beyond the epileptogenic zone, correlating this with an inferior surgical outcome. We determined whether brain volumes were reduced in childhood epilepsy and the significance of this. METHODS: Cerebral, cerebellar, and hippocampal volumes were measured by quantitative magnetic resonance imaging on 112 children (ages 4-18) with epilepsy syndrome determined by video-EEG telemetry. Eighty-seven had partial epilepsy and 25 had generalized epilepsy or indeterminate syndrome. Normative volumes were obtained from 44 child controls from the community. RESULTS: A significant reduction in cerebral (12.6%) and cerebellar (7.9%) volume was present in the epilepsy group compared with controls. Analysis of subgroups revealed that cerebral volume was significantly decreased in frontal lobe and nonlocalized partial epilepsies. The mean hippocampal ratio of 0.73 for mesial temporal lobe epilepsy was significantly less than for all other syndromes and controls. There was no difference in the rate of hippocampal volume reduction between syndromes. There was a significant correlation between IQ and cerebral and cerebellar volume, but not duration or age of onset of epilepsy. CONCLUSIONS: Cerebral and cerebellar volume reduction is common in intractable epilepsy syndromes of childhood. These cross-sectional data suggest that brain volume reduction is present at epilepsy onset and is not a result of intractable seizures. Hippocampal asymmetry is more sensitive than volume reduction as a marker for mesial temporal lobe epilepsy, but neither measure is specific.

Adolescent↗

PubMed2000

Validation of a new quality of life measure for children with epilepsy.

PURPOSE: There is no adequate measure of health-related quality of life (HRQOL) specifically for children with epilepsy. The aim of this study was to develop an epilepsy-specific HRQOL questionnaire for children, covering five domains: physical function, emotional well-being, cognitive function, social function, and behavior. Second, we aimed to demonstrate the instrument's reliability and validity, and its sensitivity to differences in epilepsy severity. METHODS: The subjects were guardians of children with refractory epilepsy, whose syndrome had been defined by using video-EEG monitoring. Each family completed the developed epilepsy-specific HRQOL scale for children and two standard, generic measures of HRQOL. RESULTS: The results indicated that each of the scales of the questionnaire had good internal consistency reliability. Furthermore, each scale correlated more highly with theoretically similar scales on established, generic health measures than with theoretically dissimilar scales (construct validity). The sensitivity of the questionnaire to differences in epilepsy severity also was demonstrated. As seizure severity increased, HRQOL subscale scores decreased, independent of age, gender, age of seizure onset, and IQ. Further, there was a negative relation between the number of antiepileptic medications taken and measures of memory and language performance, which was independent of age, gender, age of seizure onset, IQ, and seizure severity. CONCLUSIONS: This study demonstrated that the developed HRQOL instrument is a reliable and valid measure and is sensitive to differences in epilepsy. These results indicate that this new instrument may be a viable medical or surgical outcome measure for children with epilepsy.

Age Factors↗

PubMed1998

ILAE-defined epilepsy syndromes in children: correlation with quantitative MRI.

PURPOSE: The role of quantitative magnetic resonance imaging (MRI) in evaluation of childhood epilepsy remains poorly defined, with minimal published data. Previous work from our center questioned the specificity of hippocampal asymmetry (HA) in an outpatient group whose epilepsy was defined by using clinical and interictal data only. By using childhood volunteer controls and defining epilepsy syndromes using video-EEG monitoring, we readdressed the utility of HA in differentiating mesial temporal lobe epilepsy (MTLE) from other partial and generalized epileptic syndromes in children. METHODS: Seventy children were enrolled; entry criteria were age younger than 18 years with predominant seizure type recorded on video-EEG telemetry with volumetric MRI in all cases. Thirty healthy child volunteers had volumetric MRI. Epilepsy syndrome classification was according to ILAE. RESULTS: Control data revealed symmetric hippocampi, mean smaller/larger ratio of 0.96 (0.95-0.97, 95% CI) with no gender or right/left predominance. Overall 23% of patients had significant HA. Mean hippocampal ratio for MTLE was 0.78 (95% CI, 0.70-0.86), significantly lower than controls and from all other epilepsy syndromes. HA was highly specific (85%) to the syndrome of MTLE. Other potential epileptogenic lesions were found in 27 (39%) patients, lowest yield in frontal and mesial temporal syndromes. Dual pathology was present in 10% of patients. There was no significant association between HA and risk factors. CONCLUSIONS: In this study, we found that HA in children with a well-defined epilepsy syndrome is highly sensitive and specific for MTLE. Whether this will correlate with surgical outcome, as in adults, is the subject of ongoing study.

Adult↗

PubMed1997

Outcome of neonates with electrographically identified seizures, or at risk of seizures.

A prospective study was conducted to investigate survival at 1 month and survival and developmental outcome at 1 year in a cohort of 53 neonates either suspected of or at risk of having seizures. For all patients, presence of seizures, diagnoses, and structural abnormalities were identified. If seizures were present, seizure variables were quantified. Correlations between neonatal parameters and subsequent outcome were investigated. Forty-three patients survived the first month of life. Background EEG was the only significant predictor of survival at 1 month. Three patients died after 1 month, and 2 of the three had extremely depressed interictal EEGs. Development outcome at 1 year was determined for all available surviving patients. Abnormal findings from brain imaging studies and number of independent electrographic seizure foci were correlated with some aspects of outcome at 1 year. No other correlations were identified between neonatal parameters and outcome.

Child Development↗

PubMed1997

Quantitative MRI in outpatient childhood epilepsy.

PURPOSE: In adult studies, MRI volumetrics is a proven technique in presurgical assessment of epilepsy. Hippocampal volume loss is maximal in the syndrome of mesial temporal lobe epilepsy. We aimed (a) to validate this methodology in a pediatric outpatient epilepsy population (b) to determine the relationship of hippocampal asymmetry (HA) to epileptic syndromes and risk factors. METHODS: Two neurologists classified the epileptic syndrome in 79 pediatric outpatients, according to the International Classification of Epilepsies and Epileptic Syndromes (ILAE). Hippocampal volumetrics were performed in all patients. HA was defined according to adult control values. RESULTS: Inter-rater variability on measurement of HA was very small (Correlation of test retest of 0.97 on 17 children <3 years old). The rate of HA was 44/79 (57%). In 21 patients, (27%) potentially epileptogenic lesions (other than HA) were identified (cerebral dysgenesis n = 11). HA was present in 9/15 (60%) of temporal lobe epilepsy and in 15/28 (54%) extratemporal onset epilepsy and 5/11 (46%) of generalized symptomatic epilepsy. Analysis confined to <13 years also showed HA was not specific for epileptic syndrome. There was no significant association of febrile convulsions (13%) with HA or temporal lobe epilepsy. CONCLUSIONS: There is a high incidence of HA in childhood epilepsy. HA was not confined to clinically defined temporal lobe epilepsy. The poor correlation of epileptic syndrome to quantitative MRI findings may be due to the inadequacies of epilepsy classification in the younger child, with the clinical semiology providing misleading localizing information. Normative childhood data for hippocampal volumes and symmetry is needed.

Adolescent↗

PubMed1995

Non-ketotic hyperglycinaemia presenting as pachygyria.

A 2-day-old infant with lethargy and hypoventilation had pachygyria and agenesis of the corpus callosum on CT scan. Increased concentrations of glycine in plasma and CSF, together with an increased CSF/plasma ratio, confirmed a clinical diagnosis of non-ketotic hyperglycinaemia. This is the first report of pachygyria in this disorder, although agenesis of the corpus callosum is well recognized, and non-specific gyral malformations have been described previously. The specific diagnosis of an inborn error of metabolism in infants with structural brain malformations is of critical importance for accurate genetic counseling.

Amino Acid Metabolism, Inborn Errors↗

PubMed1995

Clinical features of neonatal seizures.

OBJECTIVE: Identification of seizures in neonates is difficult. This study analyses the clinical features of seizures in a cohort of neonates. METHODOLOGY: The clinical events of 41 neonates referred for investigation of suspected seizures were studied with prolonged video/electroencephalographic (EEG) telemetry. RESULTS: Sixteen neonates had no seizures recorded; 25 had confirmed seizures, 13 with clinical correlates. Each neonate with electroclinical seizures had paroxysms of abnormal movements in stereotyped patterns. These patterns were consistently found to have electrical correlates. Focal clonic movements were seen most frequently. Multiple clinical features characterized the seizure repertoire in six neonates. In five neonates the clinical features became less evident during monitoring and these seizures were difficult to recognize. This change was associated with anticonvulsant administration in three cases. CONCLUSIONS: Electroclinical seizures are characterized by abnormal paroxysmal stereotyped behaviour, often with multiple clinical features. Recommendations for the management of abnormal neonatal events are proposed.

Cohort Studies↗

PubMed1995

Spatial and temporal characteristics of neonatal seizures.

Thirty-two neonates (26 term and 6 premature) having seizures were prospectively recruited and studied. Using prolonged video/EEG monitoring, we quantified seizure variables (electrographic and clinical seizure durations, interictal periods and electrographic seizure spread) for all 1,420 seizures recorded. The effects of time and antiepileptic drug (AED) therapy were analyzed statistically. Seizures were generally frequent, with limited electrographic spread. However, some neonates had consistently longer interictal periods and 13% had mean interictal periods > 60 min. Seizure variables were relatively stable over time, but they changed with AED therapy. There was a trend to decreased seizure duration, increased length of interictal periods, and decreased electrographic spread. Furthermore, there was evidence of reduced clinical features after sequential AED infusions. Seizures ceased during the monitoring period in 22 neonates. Eighty-five percent of all seizures had no clinical manifestations. Among neonates with clear clinical correlates, clinical observations underestimated electrographic seizures in individual neonates by a mean of 54% (range 0-95%). Seizures generally had limited electrographic spread. Use of only four recording electrodes, characteristic of some portable EEG systems, underestimated seizures in 19 neonates, and missed all seizures in 2.

Anticonvulsants↗

PubMed1994

Non-accidental head injury in children.

AIMS: To analyse the clinical features, social circumstances, investigations and outcome of 49 children with significant non-accidental head injury admitted to The Prince of Wales Children's Hospital between 1979 and 1993. CLINICAL FEATURES: Age ranged from one month to eight years, with 30 children less than one year old. There were 28 boys and 21 girls. Thirty-three were in the care of a parent. Eleven of these were known to the Department of Community Services and 22 were from families with stressed socioeconomic circumstances characterised by deprivation. In 44 cases the history was incompatible with the clinical findings. On admission, 21 had marked depression of awareness, with a Glasgow Coma Scale score (GCS) of 9 or less. Eleven of this group were fitting. Seizures were present in a further 13 children who were semi-purposeful (GCS > 9). Twenty-eight had retinal haemorrhages and 35 had soft tissue scalp contusions, 23 in association with skull fracture. Twenty-six had associated injuries. Seven children died. Of the 42 survivors at the time of discharge, 19 had severe motor disability associated with other deficits. Twenty-four were returned to the care of their families. CONCLUSIONS: Retinal haemorrhage and unconsciousness on admission (GCS < or = 9) were positively associated with a poor outcome (P < 0.001 and 0.002, respectively). Cerebral oedema found on computerised tomography was positively associated with severe motor disability on discharge (P < 0.001). Lowest socioeconomic circumstances appeared to be a risk factor for occurrence of injury: 22 of 49 children came from circumstances of deprivation.

Australia↗

PubMed1994

Neonate with benign familial neonatal convulsions: recorded generalized and focal seizures.

A neonate with benign familial neonatal convulsions is presented. Ictal electroencephalography demonstrated a seizure of right frontal onset with generalization and one of right frontal onset which remained confined to that hemisphere. Very few ictal recordings of this entity exist. In this patient a partial seizure and a seizure with generalization were recorded, emphasizing the difficulties with the present classification.

Arousal↗

PubMed1993

Cortical vascular abnormalities in the syndrome of celiac disease, epilepsy, bilateral occipital calcifications, and folate deficiency.

The pathological changes in the syndrome of celiac disease, folate deficiency, bilateral occipital calcifications, and intractable epilepsy have not been previously described. A child with this disorder had a field defect correlating with active lateralized epileptic discharges and asymmetrical lesions. After resection of the right occipital lobe she was seizure free for 4 years. A cortical vascular abnormality with patchy pial angiomatosis, fibrosed veins, and large jagged microcalcifications was found. These pathological abnormalities were similar though not identical to those found in the Sturge-Weber syndrome.

Calcinosis↗

PubMed1993

Single photon emission computed tomography in intractable infantile seizures.

We aimed to determine the site of ictal foci and the pathogenesis of seizures in 4 infants with intractable seizures. The patients were studied using simultaneous video and electroencephalographic (EEG) monitoring, structural studies and ictal and interictal single photon emission computed tomography (SPECT). Ictal neurophysiology showed multifocal seizure propagation in Patients 1 and 2 and generalised abnormal electrical patterns in Patients 2, 3 and 4. Magnetic resonance imaging (MRI) demonstrated a focal abnormality in Patient 4. SPECT studies showed focal or multifocal increased uptake in 3 subjects (Patients 1,3,4) and increased uptake in the thalamic and basal ganglia regions of 2 subjects (Patients 2,3). SPECT studies contributed to an understanding of the pathogenesis of seizure initiation and propagation in the 4 patients studied.

Electroencephalography↗

PubMed1992

Staring episodes in children analyzed by telemetry.

Staring episodes in children may be ictal or nonictal, and telemetry helps make this distinction. Twenty-seven children referred to our service for elucidating the nature of their staring spells were studied by telemetry. No staring events were recorded in four children. The staring events were not associated with electroencephalographic (EEG) changes in 12 children. In 11 children, the staring events had EEG accompaniments: four had generalized spike-and-wave changes; three had focal or asymmetrical changes; and four had generalized decrement (desynchronization), which has not been described before as an electrical correlate of staring. EEG video telemetry in this group of patients led to accurate diagnosis and appropriate medical, surgical or behavioral management.

Adolescent↗

PubMed1992

Video EEG analysis of non-ictal events in children.

Over a 3 year period 186 children aged 3 weeks to 17 years were studied by telemetry (prolonged video and EEG monitoring) at the Prince of Wales Children's Hospital: 74 had events considered at referral to possibly represent seizures but which were shown by clinical analysis and telemetry to be non-ictal. Nine such patients were developmentally delayed, one was neurologically impaired and 16 were both developmentally delayed and neurologically impaired. A specific diagnosis of the non-ictal events was reached in 24 subjects-postures of spasticity in children with neurological impairment (6), Münchausen-by-proxy (5), pseudoseizures (3), breathholding (2), masturbation (2), reflux (2), shudder (1), movement disorder (1), motor tic (1) and pertussis (1). Specific descriptive patterns were assigned to the remaining 51 events. These included staring (20) and jerks (16) or unusual behaviour (15). 49 inter-event EEGs were normal; 7 displayed abnormal background rhythms and 19 showed epileptiform activity. We discourage use of the term 'pseudoseizure' for the majority of the events described and prefer that a specific diagnosis be made or a descriptive analysis be provided. The events seen illustrate the wide spectrum of childhood behaviour and on occasions suggest the need for telemetry to determine their true nature.

Adolescent↗