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Biomedical subjects

S G Boyd

Publications and source records attributed to S G Boyd.

At least 55 records · Page 3Linked to original sources
PubMed1990

The cerebral function analysing monitor in paediatric medical intensive care: applications and limitations.

Practical guidelines for continuous single channel EEG monitoring using the Cerebral Function Analysing Monitor (CFAM) have been outlined based on experience of 54 critically ill comatose and/or paralysed sedated children monitored for up to 9 days during the acute phase of illness. Fall in amplitude and slowing of frequency following either a cerebral insult or barbiturate administration as well as paroxysmal events were readily recognisable in the CFAM traces. Such changes could be used to (1) identify effects of cerebral insults (acute or cumulative), (2) recognise unstable patients exquisitely sensitive to aspects of standard care and (3) evaluate seizure control. Despite these useful contributions to clinical care, significant limitations were apparent. It is recommended that CFAM monitoring should be combined with serial conventional EEG recording in order to check the appropriateness of the cortical areas being monitored, the quality and type of signal being processed as well as the significance of the 1 or 2 channel CFAM findings in relation to global cerebral function.

Adolescent↗
PubMed1990

Myelination patterns on magnetic resonance of children with developmental delay.

Magnetic resonance (MR) imaging was performed in 30 children with unexplained developmental delay who had associated neurological abnormalities such as seizures, spasticity, hypotonia, ataxia or poor vision. No child had a history of regression, preterm birth or neonatal cerebral injury. CT scans were performed before MR in all cases and were either normal or showed only mild atrophy. At least two MR sequences were obtained for all patients. Nine children had delayed or absent myelination on MR, one had patchy white-matter abnormalities, and in one patient myelination was topographically normal, but of inappropriately low signal intensity. MR was abnormal in six of seven children who had abnormal brainstem auditory evoked potentials (BAEP), and was normal in nine of 11 patients who had a normal BAEP. MR may have a useful rôle in demonstrating abnormal white-matter maturation in children with unexplained neurodevelopmental delay, particularly when abnormalities are found on BAEP studies.

Brain↗
PubMed1989

EEG monitoring of prolonged thiopentone administration for intractable seizures and status epilepticus in infants and young children.

Thiopentone anaesthesia was used in the treatment of seizures in 19 infants and young children. Nine had a pre-existing seizure disorder without acute cerebral injury and 10 had status epilepticus secondary to an acute cerebral illness. Clinical details, drug levels and findings from serial multichannel electroencephalograms (EEG) and continuous 1 to 2 channel signal processed EEGs using a Cerebral Function Analysing Monitor (CFAM) were reviewed to evaluate the contribution of these techniques to clinical management. Initial EEGs showed discharges that were not generalised in 16/19 patients. This necessitated the use of 7 different montages for continuous monitoring. Three different CFAM patterns representing particular EEG paroxysmal findings were seen. Acute seizure control was achieved in all 19 patients. All patients with a pre-existing seizure disorder survived, although 4/10 with an acute cerebral illness died. During treatment, patterns of burst-suppression to electrocerebral silence (ECS) were eventually seen in 16/19 patients and repeat EEGs demonstrated concordant multi-channel findings in 8/8. Although increasing thiopentone levels (13 patients) correlated with deeper suppression of cortical electrical activity, there was marked inter-patient variability. Inotropic support was not required during the period of treatment even when ECS was induced. In young children a combination of multi-channel EEG and continuous 1 to 2 channel monitoring has advantages over either method used alone. In individual patients on-line monitoring can be easily incorporated in a protocol of controlled cortical suppression and drug titration for seizure control.

Child, Preschool↗
PubMed1989

Rett syndrome: an EEG study in 52 girls.

EEG studies have been carried out on 52 girls with Rett syndrome, the majority of records being taken between two and 7 years of age. Discharges were a common feature, occurring in 43 patients, and did not appear to be related to the onset of seizures. The discharges, consisting of sharp waves or spikes, were characteristically most prominent around the middle third of the head, often occurring asymmetrically and could be infrequent or almost continuous. They were usually enhanced by light sleep and were seen only during sleep in 15 EEGs taken in 13 patients, most of whom were under four years of age. These EEG features when present may help confirm the diagnosis of Rett syndrome in the appropriate clinical setting and in particular are quite distinct from the usual EEG patterns seen in Angelman (Happy Puppet) syndrome.

Adolescent↗
PubMed1989

Clinical neurophysiological assessment of children with sacral anomalies.

Clinical neurophysiological investigations were carried out in 8 children with various forms of sacral dysplasia. No EMG activity was found in leg muscles in two children with complete sacral agenesis, even though pelvic floor activity was preserved in one of these. The external anal sphincter and puborectalis were examined in all cases, and it was easy to demonstrate neuropathic changes in individual motor unit potentials by attenuation of their low frequency components. There was only a loose association between any pelvic floor neuropathy and the level of the bony defect in the sacrum, confirming recent reports. Trans-cutaneous stimulation of the spinal nerve roots in the lumbar canal was carried out in four children. Unilateral slowed conduction in L5 roots corresponded with the clinical signs in one patient, and absent innervation of leg muscles was confirmed in the two children with complete agenesis. Normal L1-L4 conduction times were found in a child with no clinical signs. Early assessment of children with sacral anomalies is important in order to prevent secondary complications. Clinical neurophysiological investigations are useful in delineating the different patterns of neurological involvement, especially in the pelvic floor, and the results complement those obtained with imaging techniques.

Anal Canal↗
PubMed1989

Effects of halothane on motor evoked potential recorded in the extradural space.

We studied the effects of supplementing nitrous oxide-oxygen anaesthesia with halothane (1 MAC end-tidal concentration) on the motor evoked potential recorded in the extradural space of eight patients before corrective surgery for idiopathic adolescent scoliosis. The motor cortex was stimulated electrically through the scalp. An additional eight patients in whom anaesthesia was supplemented with an infusion of propofol acted as a control group. Halothane had no significant effect on the amplitude or latency of the motor evoked potential. We conclude that halothane is unlikely to alter the interpretation of motor evoked potentials recorded extradurally during scoliosis surgery.

Adolescent↗
PubMed1988

The EEG in early diagnosis of the Angelman (happy puppet) syndrome.

An EEG study has been carried out on 19 children (including siblings in 3 families) with clinical features of Angelman syndrome. The age at time of the first EEG ranged from 11 months to 11 years with the majority under 5 years. Six children had no history of seizures at the time of the first EEG. One or more of the following EEG abnormalities were seen in all patients: 1. Persistent rhythmic 4-6/s activities reaching more than 200 microV not associated with drowsiness. 2. Prolonged runs of rhythmic 2-3/s activity (200-500 microV) often more prominent anteriorly, sometimes associated with discharges (ill-defined spike/wave complexes). 3. Spikes mixed with 3-4/s components usually more than 200 microV mainly posteriorly and facilitated by, or only seen with, eye closure. Two and sometimes three of these EEG features could be present in the same record particularly at a young age. The appearance of discharges mixed with slow components on eye closure was the commonest finding seen at some stage in 17 patients (aged from 11 months to over 12 years). The EEG features of Angelman syndrome appear to be sufficiently characteristic to help identify patients at an early age before the clinical features become obvious and at a time when genetic counselling may be particularly important.

Adolescent↗
PubMed1987

Progressive neuronal degeneration of childhood with liver disease. Computed tomographic features.

The clinical, electrophysiological and neuroradiological features of thirteen patients suffering from progressive neuronal degeneration of childhood with liver failure are presented. The disease commonly presents very early in life with progressive mental retardation, followed by intractable epilepsy, and should be suspected clinically especially if there is a family history of similar disorder in a sibling. On computed tomography there are low density regions, particularly in the occipital and posterior temporal lobes, involving both cortex and white matter, combined with or followed by progressive atrophy. Typical EEG findings may be confirmatory.

Age Factors↗
PubMed1987

Progressive neuronal degeneration of childhood (PNDC) with liver disease.

Thirteen children with progressive neuronal degeneration and liver disease are reported. Clinical features included developmental delay after a normal initial period with later onset of intractable epilepsy. The EEG showed an unusual but characteristic pattern, and visual evoked responses (VER) were abnormal. Rapidly progressive cerebral atrophy was seen on computerized axial tomography (CAT). Inheritance was consistent with an autosomal recessive trait. Pathological findings were neuronal degeneration and spongy change of the cerebral cortex. The calcarine cortex was more severely affected than other areas. Hepatic lesions included severe fatty change and cirrhosis. In six patients liver disease was detected before the onset of epilepsy and exposure to anticonvulsants. Two others were reported to have died from sodium valproate (SV) toxicity, but both had abnormal liver enzymes before treatment with SV, and in both the neuropathological findings were indicative of PNDC. During life, PNDC may be indicated by the characteristic clinical course, abnormal liver function tests, and abnormalities of EEG, VER, and CAT.

Brain↗
PubMed1986

Progressive neuronal degeneration of childhood with liver disease ("Alpers' disease"): characteristic neurophysiological features.

A clinico-pathological entity of progressive neuronal degeneration of childhood with liver disease has now been recognised. Onset is in early childhood with intractable fits and progressive dementia. EEG/ERG/VEP studies have been carried out in 12 children with this condition. In most patients the EEG showed strikingly similar and unusual abnormal patterns (high amplitude slow activity together with smaller polyspikes). The flash VEP was usually abnormal and often asymmetrical. In the appropriate clinical setting the neurophysiological features are sufficiently characteristic to aid the clinician in early diagnosis of this autosomal recessive disorder.

Atrophy↗
PubMed1986

A method of monitoring function in corticospinal pathways during scoliosis surgery with a note on motor conduction velocities.

Spinal cord potentials produced by high voltage electrical stimulation of the scalp over the motor cortex were recorded intraoperatively from bipolar electrodes inserted into the epidural space of eleven patients undergoing corrective surgery for scoliosis. Responses to single stimuli could be recorded from the cord at all levels from cervical to low thoracic regions. The potentials were larger in the cervical than in the thoracic region and sometimes were followed by later waves at high stimulation intensities. Conduction velocity in large corticomotoneuron fibres was estimated to be between 50-74 ms-1 in different patients. This technique for monitoring motor tract function may be a useful adjunct to conventional monitoring of the sensory pathways during surgery.

Adolescent↗