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Biomedical subjects

D W Chadwick

Publications and source records attributed to D W Chadwick.

At least 73 records · Page 4Linked to original sources
PubMed1995

Accident experience and notification rates in people with recent seizures, epilepsy or undiagnosed episodes of loss of consciousness.

Collaborating neurologists provided a central office with clinical information, driving experience and accident rates in all drivers they counselled after diagnosing seizures or other unexplained episodes of loss of consciousness. Each patient received and was asked to return a notification slip to DVLA. Of 638 patients counselled, 11% had been involved as a driver in a road traffic accident in the previous year. Six patients had been involved in an accident producing serious injury. These estimates do not differ from those expected in a population of non-epileptic drivers with the same age and sex distribution. Of patients counselled, 27.1% returned a reply slip to the DVLA. Notification was more likely if the patient was aged 50 or over at the time of counselling, if the counselling was undertaken by a consultant, if an accident had occurred in the previous year and if the subject had also been advised to start or was already taking anti-epileptic drugs. Patients counselled after a single seizure were more likely to notify than those with a diagnosis of epilepsy.

Accidents, Traffic↗
PubMed1993

The initial development of a health-related quality of life model as an outcome measure in epilepsy.

Patients with refractory epilepsy, despite no fixed physical deficit, are often socially and psychologically handicapped. Currently available outcome measures for epilepsy do not adequately address these manifestations or their influence on well-being and quality of life. A patient-based health-related quality of life (HRQL) model for epilepsy including physical, social and psychological domains was constructed. It contains previously validated measures of anxiety, depression, happiness, overall mood, self-esteem, mastery, social satisfaction and general health and a specifically designed seizure severity scale with patient- and carer-based components. The psychometric properties of this model were evaluated in the context of the trial of a potential new antiepileptic drug. All the scales, except the Social Problems Questionnaire, have acceptable internal consistency (alpha 0.69-0.85) in this patient population. Construct validity is indicated by the ability of the scales to differentiate between groups of patients predicted to have different levels of psychosocial function. Treatment effects were detected by the patient (P = 0.017) and carers (P = 0.035) subscales of the seizure severity scale, the happiness (P = 0.003) and the mastery (P = 0.003) scales. Despite obvious deficiencies preliminary analyses are encouraging. This model provides a framework for investigating the complex interaction between the physical, social and psychological manifestations of epilepsy. The model has potential as an outcome measure for use in longitudinal studies and as a measure of disability for use in cross-sectional studies designed to compare quality of life in different populations of people with epilepsy.

Activities of Daily Living↗
PubMed1993

Opsoclonus-myoclonus syndrome: an autopsy study of three cases.

Opsoclonus-myoclonus is a rare clinical syndrome. We report three patients who died with a pure opsoclonus-myoclonus syndrome. The presentation, management and associations of this distinctive condition are discussed, and the results of detailed pathological examination described. In each case the only abnormality was perivascular collections of lymphocytes widely distributed in the brain. This supports an immune-mediated rather than structural aetiology.

Aged↗
PubMed1992

Development of prognostic index for primary supratentorial intracerebral tumours.

The clinical course of intrinsic supratentorial tumours is variable. Prediction of outcome would be useful in defining patients for specific treatment policies. A retrospective analysis of 560 patients with intrinsic supratentorial tumours was performed. Proportional hazards models for survival were derived by using a stepwise selection procedure with only clinical and CT features as possible explanatory variables. The variables of prognostic importance were age, a first symptom of epilepsy, focal signs at presentation, a cystic lesion on CT scan, and duration of symptoms before presentation. The model defined a group with a good prognosis (score less than or equal to 9, n = 211) and a group with a poor prognosis (score greater than 9, n = 344). The median survival was 27 months for those with a score less than or equal to 9 or less and three months for those with score greater than 9. An alternative model, not including duration of symptoms, is also capable of defining groups with long (score less than or equal to 16, n = 234) and short (score greater than 16, n = 325) survival. The model may provide a means of classifying patients for inclusion in prospective randomised studies.

Actuarial Analysis↗
PubMed1992

Do prophylactic anticonvulsant drugs alter the pattern of seizures after craniotomy?

A total of 276 patients with a high risk of developing postoperative seizures were randomised to treatment with carbamazepine or phenytoin for six or 24 months, or to no treatment. No significant differences were found (though the confidence limits were fairly wide) between the regimes in respect of the incidence of seizures or death. In a substantial proportion of the patients postoperative epilepsy remained a continuing disability. A high incidence of drug-related side effects was found in the treatment groups. Prophylactic anticonvulsants cannot therefore be recommended routinely following supratentorial craniotomy.

Actuarial Analysis↗
PubMed1991

Seizure frequency, patient-perceived seizure severity and the psychosocial consequences of intractable epilepsy.

It is generally recognised that the assessment of treatment effects in epilepsy using seizure frequency as the only outcome measure may lack sensitivity. A patient-based seizure severity scale has been developed and initial results confirm its reliability and validity. As part of the further development of this scale it is important to explore the relationship between seizure severity, seizure frequency and the psychosocial consequences of intractable epilepsy. One hundred patients with medically refractory partial seizures completed a quality of life questionnaire including measures of physical (seizure severity and frequency), social and psychological well-being (anxiety, depression, self-esteem, locus of control and happiness). Multivariate analysis demonstrated that individual psychological variables were best predicted by other psychological variables. However, when these were removed from analysis, seizure severity was the most significant predictor of self-esteem (P = 0.005), locus of control P = 0.039) and anxiety (P = 0.048). Seizure frequency did not contribute significantly to the variance of any of the psychological factors. These results highlight the importance of considering seizure severity when assessing treatment effects in epilepsy and provide further evidence for the construct validity of a novel patient-based seizure severity scale.

Activities of Daily Living↗
PubMed1991

The development of a seizure severity scale as an outcome measure in epilepsy.

In controlled trials of antiepileptic drugs (AEDs) seizure frequency is often the only variable considered. With little prospect of improving assessment of AEDs, using seizure counts as the only end-point, there is a need for the development of new outcome measures. Clinical experience indicates that seizure severity is equally important to the patient and, by preventing seizure spread, AEDs can influence seizure severity without necessarily reducing seizure frequency. A scale capable of measuring seizure severity and change of severity attributable to treatment could be a useful additional outcome measure. Such a scale should exhibit the basic properties of validity and reliability. An easily administrable 16-point scale, containing 2 subscales--perception of control and ictal/post-ictal effects--has been developed. This scale has been tested on a patient population (n = 159) representative of that seen in trials of novel AEDs. Using standardised statistical methods, the scale has been shown to be both reliable and valid.

Adolescent↗
PubMed1991

The prognosis of primary intracerebral tumours presenting with epilepsy: the outcome of medical and surgical management.

It is not known whether conservative or early aggressive (resective surgery with or without radiotherapy) management is better for tumours presenting with epilepsy. The prognosis of 560 patients with a clinical and CT diagnosis of intrinsic supratentorial tumour was examined retrospectively. Epilepsy was the first symptom in 164 patients. Histological confirmation of diagnosis was available in 391 (70%) of cases. Median survival was 37 months in the group presenting with epilepsy and six months in those presenting with other symptoms (p less than 0.0001). Patients presenting with epilepsy were more likely to have a normal clinical examination, a non-enhancing low density lesion on CT scan and a low grade tumour. From Cox's stepwise proportional hazards model, significant independent variables adversely affecting prognosis were increasing age, focal neurological signs and enhancing CT lesions at diagnosis, non-resective surgery and male sex. Of those presenting with epilepsy 80 patients had surgical treatment within two months of CT diagnosis. The Cox's model failed to identify any beneficial effects for either early resective surgery or radiotherapy. In primary intracerebral tumours with presentations other than epilepsy, resective surgery and radiotherapy were amongst the important factors associated with prolonged survival. Primary intracerebral tumours presenting with epilepsy are relatively benign and their outcome appears to be chiefly determined by clinical factors.

Adolescent↗
PubMed1991

Extracranial vertebral artery dissection following tonic clonic seizure.

A 34 year old woman developed cerebral infarction, following a tonic-clonic seizure. A vertebral artery dissection was demonstrated and may have been caused by arterial trauma during the seizure. This cause of morbidity following convulsive seizures may have been overlooked in the past and needs to be recognised in view of the potential benefits of anticoagulation.

Adult↗
PubMed1990

The management of patients with an intrinsic supratentorial brain tumour.

The management of patients presenting with supratentorial glioma between 1978 and 1986 is reviewed. Complete follow-up in 517 cases was obtained. One hundred and fifty eight patients were not submitted to any form of surgery, 299 patients were biopsied and 60 patients underwent craniotomy and internal decompression. The no surgery group contained a higher proportion of patients with poor prognostic indicators than either the biopsy or craniotomy groups. The craniotomy group consisted of patients with better prognostic indicators than the biopsy group, in particular, younger age and more favourable site, type and grade of tumour. This was reflected in the difference in outcome between the groups. Median survival was 14 months in the craniotomy group, four months in the biopsy group and 2.2 months in the no surgery group. The outcome in patients with histologically proven malignant gliomas was best in those patients who received radiotherapy. The craniotomy group had a median survival of 18.5 months, a two year survival of 48% and a five year survival of 9%. The median survival following radiotherapy of those patients with proven malignant gliomas who had a biopsy was 9.5 months with a two year survival of 16% and a five year survival of 2%. These results compare favourably with studies which have adopted a more aggressive approach, suggesting that outcome is determined as much by patient selection using favourable prognostic indicators as by the treatment itself. The need for prospective trials of the management of unselected consecutive glioma patients randomizing them to conservative and radical treatment groups in order to define the role of both conventional therapy and radical therapy is discussed.

Adolescent↗
PubMed1989

Pseudostatus epilepticus.

Thirteen patients with pseudostatus (simulated status epilepticus) have been compared to 13 patients with true status epilepticus seen at a regional neurological centre. Pseudostatus was common in patients with pseudoseizures and was often misdiagnosed as status epilepticus. Complications of this misdiagnosis included eight episodes of anticonvulsant-induced respiratory arrest. Patients with pseudostatus commonly had multiple episodes of 'status'. They usually also had a history of other unexplained illness and of deliberate self-poisoning. Management of these patients was difficult and emphasizes the need for specialist expertise for patients with epilepsy and apparent epilepsy.

Adolescent↗
PubMed1988

CSF gradients for amino acid neurotransmitters.

Amino acid concentrations were measured in CSF samples obtained by lumbar puncture in 51 patients, cervical puncture in 16 patients, spinal drains in nine patients, ventricular taps in five patients and from below a spinal block in six patients. There was evidence of a rostrocaudal gradient for GABA and taurine and a reverse gradient for alanine and asparagine. Lumbar CSF glycine concentrations rose with increasing age whilst GABA concentrations fell. Women had significantly lower concentrations of asparagine and glutamine and elevated taurine compared to men. The influence of biological factors and gradients must be taken into account before the interpretation of changes in CSF amino acid concentrations.

Adult↗
PubMed1988

Post-ictal blood pressure in aneurysmal subarachnoid haemorrhage.

A prospective study in which the effect of the post-ictal systemic blood pressure levels on the outcome following surgically treated aneurysmal subarachnoid haemorrhage (SAH) in 325 patients is reported. No differentiation was made between pre-existing essential and prolonged reactive hypertension. A significant association was found between the trend for rising diastolic blood pressure levels and the tendency towards a poor outcome. There was a similar trend for rising systolic blood pressure levels which did not reach statistical significance. Patients with definite hypertension (blood pressure of 160/95 mmHg or greater) were 1.6 times as likely to have a poor outcome than were those with lower blood pressures.

Adult↗
PubMed1988

Recurrent aneurysmal subarachnoid haemorrhage: incidence, timing and effects. A re-appraisal in a surgical series.

A series of 510 patients with proven aneurysmal subarachnoid haemorrhage (SAH) is reported. The incidence of recurrent haemorrhage during the period awaiting surgery was 13.7%. There was no significant difference in incidence between good and poor grade patients. Following rebleeding there was an immediate mortality of 34% in good grade patients and 52% in poor grade patients. In the long term only 44.4% of good grade and 8% of poor grade patients made a good recovery following a second bleed as compared to 70.6% and 52.8% respectively for those who did not rehaemorrhage.

Humans↗
PubMed1987

Valproate monotherapy in the management of generalized and partial seizures.

For decades, therapeutic tradition has promoted the concept of polypharmacy in the management of epilepsy. In recent years, however, studies have shown that, for most patients, monotherapy can provide comparable or better seizure control than administration of multiple anticonvulsants, while diminishing the potential for adverse reactions, drug interactions, and poor compliance. Valproate is an important monotherapeutic agent that is highly effective in the control of idiopathic primary and secondarily generalized epilepsies, and partial seizures that do not generalize. Comparative studies have found that valproate is at least as effective as phenytoin and carbamazepine in the treatment of generalized and partial seizures. Given the similar efficacy, other factors such as pharmacokinetics and side effects may therefore determine anticonvulsant selection for monotherapy.

Clinical Trials as Topic↗