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Biomedical subjects

A Keyser

Publications and source records attributed to A Keyser.

At least 55 records · Page 3Linked to original sources
PubMed1995

Monotherapy or polytherapy for epilepsy revisited: a quantitative assessment.

Some investigators argue that treating epilepsy with several antiepileptic drugs (AEDs) simultaneously (polytherapy) may give rise to more adverse effects than monotherapy, but this argument lacks supporting quantitative data. To reexamine this issue, we recruited a cohort of patients from the outpatients of the Special Centres for Epilepsy in The Netherlands and from the outpatients of the Department of Neurology, Nijmegen University, The Netherlands. Two tools were used for analysis. All daily doses of antiepileptic drugs (AEDs) were standardized by the ratio of prescribed daily dose to defined daily dose (PDD/DDD). The DDD is the assumed average effective daily dose for a drug used for its main indication in adults. The assignment of DDD values is the task of the World Health Organization (WHO) Collaborating Centre for Drugs Statistics Methodology and Nordic Council on Medicines, which regularly publishes Guidelines for Defined Daily Doses. The severity of adverse effects (AE) was assessed by using the Neurotoxicity Index and the Systemic Toxicity Index as developed by the VA Cooperative Study Group for their recent studies comparing the efficacy and tolerability of AEDs. One hundred sixty-one patients received monotherapy; all had a PDD/DDD ratio < or = 2/day; 128 of 262 patients receiving polytherapy also had < or = 2 PDD/DDD ratios/day. The mono- and polytherapy groups were stratified according to the PDD/DDD ratio. The prevalence of neurological AE for patients with similar PDD/DDD ratios was 50-80% for monotherapy patients and 50-82% for polytherapy patients. The difference between the mono- and polytherapy groups was not significant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Clinical neurological trauma parameters as predictors for neuropsychological recovery and long-term outcome in paediatric closed head injury: a review of the literature.

We present a review of recent prospective studies of long-term outcome in paediatric closed head injury. Special attention is given to the relationship between the neurological trauma parameters and neuropsychological outcome. First we discuss the most important methods of assessing the severity of the injury. We review the most prominent neurobehavioural and cognitive sequelae. Subsequently we address the question of prediction of residual sequelae in view of the early trauma parameters. The main problem when comparing different studies is the lack of procedural uniformity both in assessment of the severity of the injury as well as in measurement of neuropsychological outcome. Inconsistencies and discrepancies among various studies are pointed out. We summarise those results which are supported by many studies and hence are less controversial. In addition we present some recommendations for future investigations.

Brain Damage, Chronic↗
PubMed1994

Epilepsy treatment in The Netherlands. Comparison of matched groups of two medical centres.

To test the feasibility of comparing epilepsy treatment policies and outcome, a secondary and a tertiary epilepsy care facility have been audited in a previous study (1). Marked differences were observed in the treatment policies and outcome and in the distribution of seizure types and duration of epilepsy. For this reason the patients of that study were matched according to seizure type and duration of epilepsy, resulting in two groups each of 32 patients per centre. The outcome of treatment was assessed by using clinimetrical indexes for seizure frequency and severity and toxicity of medication, resulting in the Composite Index of Impairments (CII), reflecting all treatment-related impairments. For the statistical analysis the X2-test and the Kruskal-Wallis test were used. Differences were found to be statistically significant when p < 0.05. No distinct differences were found in the treatment policies of both centres. However, differences were observed in the outcome of treatment. The toxicity ratings in this study were significantly higher for the Epilepsy Centre. Also the Composite Index of Impairments (CII) was significantly higher at the Epilepsy Centre. The number of patients with a CII score of > 100 did not differ significantly for both centres. The finding that pharmacotherapy is similar in both centres, suggests that pharmacotherapy is pushed to its limits in both, and that referral to a tertiary facility is mainly for the non-pharmacotherapeutic care modalities available. For the corroboration of this assumption the use of a quality of life index would be more appropriate than the CII.

Adolescent↗
PubMed1993

Platelet aggregation inhibitors in neurology.

This literature review reports on secondary prevention of ischaemic stroke. The aim of secondary prevention is to protect patients who belong to a risk group from the occurrence of brain infarction. Symptomatic patients with a demonstrated carotid artery stenosis of 70% and more will most probably benefit from carotid endarterectomy if performed by a skilled surgeon in the absence of contraindications. Oral anticoagulant drugs play a minor role in the medical prevention of brain infarction. Antiplatelet drugs, however, have been in use for almost two decades and (meta-)analysis of clinical trials points to acetylsalicylic acid as a drug with a modest but certain contribution of about 15% in the endpoint reduction, even at lower dosages. The addition of dipyridamole to classic acetylsalicylic acid dose appears to increase the endpoint reduction to 30%. Neither dipyridamole nor sulfinpyrazone as monotherapy have been demonstrated to be efficacious in the secondary prevention of ischaemic stroke. Ticlopidine seems a promising alternative for acetylsalicylic acid in those patients who suffer adverse effects from acetylsalicylic acid. Ticlopidine itself, however, has a number of side-effects that limit its application. New clinical trials are under way in order to improve the efficacy of drug treatment in the secondary prevention of brain infarction.

Brain Ischemia↗
PubMed1993

Mitochondrial encephalomyopathy, lactic acidosis and stroke in adults: two cases.

Two previously healthy women are described who in their late thirties suffered transient strokelike episodes, consisting of initial headache and vomiting, with various subsequent neurological signs that were only partially reversible. Investigations revealed elevated serum creatine kinase, lactic acidosis, hypertriglyceridaemia, and ragged red fibres in the muscle biopsy specimens. In both patients in vitro studies were performed on intact muscle mitochondria and muscle homogenate. Only in one was a mitochondrial defect found, located at the level of coenzyme Q. We conclude that these patients suffered from adult-onset mitochondrial encephalopathy, lactic acidosis and strokelike episodes (MELAS syndrome). Although the syndrome is often associated with long-standing neurological multisystem disease from childhood onwards, it should also be suspected in adults with strokelike signs of otherwise unexplained origin.

Adult↗
PubMed1993

The relation between neurological trauma parameters and long-term outcome in children with closed head injury.

In a study of 54 children with closed head injury, the relation between neurological severity indicators and the occurrence of long-term sequelae was investigated. Patient data were recorded during the clinical phase and during a 2 year follow up period. A correlation analysis identified early predictors for the occurrence of long-term sequelae. In particular, the duration of coma and of post-traumatic amnesia correlated strongly with the occurrence of neurological, behavioural and intellectual residual sequelae but not with the more subjective complaints.

Adolescent↗
PubMed1993

Delay in diagnosis of X-linked adrenoleukodystrophy.

In 16 consecutive patients with clinically suspected and biochemically proven X-linked adrenoleukodystrophy (X-ALD), total delay (interval between onset of symptoms and diagnosis) and specialist delay (interval between referral to a specialist and diagnosis) were determined. All patients previously were unaware of the existence of X-ALD in their families. From the time of onset of symptoms attributable to this disease until diagnosis, mean total delay was 9.9 (range 1-33) years and mean specialist delay was 8.4 (range 0-33) years. Three patients who presented with adrenocortical insufficiency had mean total and specialist delays of 17.3 (range 9-33) years. Five patients with an initial diagnosis of multiple sclerosis had mean total and specialist delays of 12.8 (range 5-25) and 11.2 (range 1-23) years, respectively. In 12 patients with adrenomyeloneuropathy--the second most frequent phenotype of X-ALD--mean total delay was 11.0 (range 2-33) years and mean specialist delay 9.1 (range 0-33) years. Since 1981 X-ALD can be reliably diagnosed on the basis of elevated levels of very long chain fatty acids in plasma and/or cultured fibroblasts. The delays therefore must have been due to the unfamiliarity with the clinical manifestations and diagnostic possibilities of this disease. Once X-ALD is diagnosed, dietary treatment and/or bone marrow transplantation may be considered. Genetic counseling should be performed, and screening of other family members is essential for the early identification of affected relatives.

Addison Disease↗
PubMed1993

Somatosensory evoked potentials and cognitive sequelae in children with closed head-injury.

In search of a prognostic indicator for residual cognitive function loss in children after closed head-injury, the somatosensory evoked potential P300 has been studied in a prospective follow-up study of 17 patients with mild and moderately severe head-injuries. The P300 response was measured in the acute phase after patients regained consciousness. In addition the duration of coma and of post-traumatic amnesia were recorded. An age-matched control group of 20 healthy children supplied age-related normative evoked potential data. During a two-years follow-up period the presence of residual disorders in various faculties was evaluated at fixed time intervals after discharge. Correlation analyses revealed that, where the duration of coma and of post-traumatic amnesia qualify as general predictors of sequelae, the long-latency somatosensory evoked potential P300 correlated specifically with long-term deficits in the field of school performance.

Achievement↗
PubMed1993

Epilepsy treatment in The Netherlands. Comparison of two medical centres.

In order to test if it is feasible to compare epilepsy treatment policies, a secondary (University Hospital) and a tertiary referral care centre (i.e. an Epilepsy Centre) were compared with respect to their characteristics, the treatment approaches, and the outcome of treatment using clinimetric indexes. At the Epilepsy Centre a greater variety of seizure types was seen than at the University Hospital. At the University Hospital more patients were treated with monotherapy (62.5%) than at the Epilepsy Centre (28.0%). The Composite Index of Impairments (CII), which reflects all treatment related impairments i.e. seizures and adverse events, was significantly higher at the Epilepsy Centre than at the University Hospital. No difference was seen in the groups of patients with a high score of the CII (> 100). Further analysis is needed to obtain an answer as to why differences between the two groups exist.

Academic Medical Centers↗
PubMed1992

Assessment of post-traumatic amnesia in young children.

To assess the duration of post-traumatic amnesia (PTA) in children, a new procedure is described, derived from a method described previously for adults. The procedure was tested on 70 healthy children between 3.5 and 10 years of age, then applied in a longitudinal prospective study of 54 children with brain damage resulting from closed head-injury. The procedure consistently measured PTA in children of various ages. The duration of PTA was found to be as good a prognostic indicator for the occurrence of long-term residual sequelae as is duration of coma.

Amnesia↗
PubMed1991

Clinimetrics and epilepsy care.

In order to study the practicability of rating scales in the regular care of people with epilepsy, indices have been developed and tested on their validity. These indices consist of the Index of Seizures, representing seizure activity, and the Composite Index of Impairment concerning the severity of impairment caused by the seizure type and frequency and the side-effects of anti-epileptic drug treatment. The indices have been applied in a retrospective quantitative evaluation of anti-epileptic drug therapy. The medical records of 250 randomly selected patients registered at an adult out-patient clinic have been reviewed. Their seizures have been classified as generalized tonic-clonic, simple partial and/or complex partial. The distribution of this population according to these indices has been studied, which leads us to the following conclusions: the global indices are valid for clinical application; in 18.6% of the patients studied there was severe impairment and unacceptable seizure control; combined types of seizure are difficult to control; no significant difference is demonstrated between monotherapy and polytherapy regarding the amount of neurotoxicity. The indices can be determined rapidly and therefore may become valuable aids for the physician in an out-patient clinic to support a decision whether or not to revise current anti-epileptic drug therapy.

Epilepsy↗
PubMed1991

Epileptic manifestations and vitamin B1 deficiency.

Sixteen of 50 consecutive neurological patients with a diagnosis of thiamine deficiency showed epileptic (10) or epileptiform (6) manifestations. A survey of the literature revealed only few reports on a possible relationship between epilepsy and thiamine deficiency. It appears that thiamine deficiency may provoke epileptic phenomena in those patients who have subclinical predisposition for seizures. The presence of irritative activity on electroencephalographic recordings in the patients may be a consequence of a vitamin B1 deficiency state. The possible pathophysiological mechanisms by which thiamine deficiency may contribute to seizure activity of the brain are discussed.

Adult↗
PubMed1990

Side-effects of drugs in epileptic patients.

Drug therapy in patients suffering from various forms of epilepsy aims at the administration of such dosages of antiepileptic drugs as to produce significant reduction of seizures without the occurrence of serious side-effects. To assess these side-effects 75 patients (48 males, 27 females) with epilepsy, attending an out-patient clinic were studied prospectively and data were collected regarding diagnosis, drug use and side-effects. Primarily generalized epilepsy and partial complex epilepsy with secondary generalization are the most prevailing categories. 69% (52) Of the patients are treated with monotherapy, with carbamazepine as the drug most frequently prescribed (30/52). Side-effects were scored after examining and questioning the patient with the help of a standard questionnaire. A distinction was made between groups of side-effects, being systemic, anamnestic, dermatological, neurological or miscellaneous. Also, haematological and biochemical changes were looked for. In the monotherapy group 26/52 (50%) of the patients showed side-effects (23 patients with 1, 2 with 2, 1 with 3 side-effects), and in the polytherapy group 15/23 (65%) (8 patients with 1, 7 with 2 side-effects). Adverse drug reactions were hardly related to the plasma concentration category. Between 50-60% of the patients at sub-therapeutic and low-therapeutic plasma levels complained of side-effects. No clear relationship between the clinical efficacy and the side-effects could be established. The clinical custom, among others, to titrate the dose according to the disappearance or appearance of side-effects seems open for discussion.

Adult↗
PubMed1990

Long-term sequelae of brain damage from closed head injury in children and adolescents.

A study was made of the sequelae of brain damage in young patients. Seventy patients between 4 and 18 years, admitted under the diagnosis "diffuse brain contusion", have been followed at least two years after head injury. The degree of function impairment in the fields of motor skills, cognition and behaviour was recorded. It was found that many patients with neurologically little or no function loss, nevertheless after the accident did suffer from psychosocial problems in the realm of family life, school or profession. Based on these findings, the authors recommend a consequent and systematic follow up of patients if they have been in coma for more than 1 hour, the objective being the early assessment of such dysfunctions, followed by adequate assistance.

Adolescent↗
PubMed1989

Retrospective analysis of drug treatment in epileptic patients.

An epidemiological analysis was performed of the adult, out-patient epilepsy clinic population of a university hospital during the period from 1 January 1981 through 30 June 1985. The number of patients that could be traced amounted to 590. An at random sample of 207 were retrospectively analysed. Gender distribution was male:female = 1.46. The mean age was 37.4 years. The diagnoses were classified according to the classification of the International League Against Epilepsy (ILAE). A preponderance of partial seizures was present, reflecting the selection in a university out-patient clinic of more difficult to treat forms of epilepsy. Antiepileptic drugs used in the treatment varied; monotherapy was obtained in 46% of the cases and carbamazepine was the most frequently prescribed drug (49%). Changes in seizure severity and factors associated with epilepsy are described. A discrepancy was found between the suspected drug levels, based upon the physician's judgement, and the plasma level measured in those patients in whom drug levels were monitored; factors interfering with clinical judgement are discussed.

Adolescent↗
PubMed1988

Improvement of IVDSA of the brachiocephalic arteries using a non-ionic contrast medium.

The introduction of IVDSA provides a safer method of angiographic investigation of the aortic arch and brachiocephalic arteries than conventional angiography in patients with cerebro-vascular disease. The quality of visualization however decreases. Instead of changing over to IADSA we find it worthwile to try to improve IVDSA in different ways. One of them is represented in this prospective double blind cross-over study in which we have investigated the effects of using an isotonic non-ionic contrast medium, iohexol (omnipaque), in comparison to meglumin-sodium-diatrizoate (urografin) which is widely used. Iohexol causes less severe side-effects, less severe artifacts and a better image quality. A statistical relation between parameters could not be established. A lag-effect exists for side-effects. The necessity of using low osmolar contrast media is discussed.

Angiography↗