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Biomedical subjects

W Burr

Publications and source records attributed to W Burr.

At least 37 records · Page 2Linked to original sources
PubMed1986

Epileptic activity during sleep and wakefulness.

In 23 untreated patients the temporal distribution of generalized spike-wave activity was investigated by means of mobile long-term EEG recordings. Distribution classes (S, A, W) were defined if the relative amount of epileptic activity within the phases sleep, awakening and waking exceeded a threshold, otherwise a diffuse distribution (D) was scored. A, S and D distributions were found approximately with the same frequency. In no patient was the middle part of the night most prominent. In one patient, it was shown by micro-hypnograms that 'micro-arousals' are closely related to spike-wave activity.

Adolescent↗
PubMed1986

Prescribing in pregnancy. Thyroid disease.

When treating thyroid disease, as with other conditions in pregnancy, one is concerned with the welfare of both mother and developing child. Thyroid disease causes few maternal problems; thyrotoxicosis in fact tends to improve in pregnancy, allowing medical management with lower drug doses than usual. Relapse of thyroid disease may occur postpartum, when transient hypo- and hyperthyroidism are relatively common. In contrast, the fetus and neonate are threatened in a number of ways by drugs given to the mother and by transplacental passage of maternal antibodies capable of inducing thyroid disease. Antithyroid drugs may cause fetal goitre with airway obstruction, and are associated with mild neonatal hypothyroidism. Thyroid antibodies in primary myxoedema and Hashimoto's thyroiditis are occasionally implicated in neonatal hypothyroidism and may even cause thyroid dysgenesis. Neonatal hyperthyroidism has a high morbidity and mortality and may have long-term skeletal effects such as craniosynostosis. Fetal problems may not be apparent at birth but may emerge in the next eight to ten days, especially in hyperthyroidism when the mother has been on treatment. Close monitoring throughout pregnancy and for the first ten days postpartum is required to minimize risks to the fetus and neonate. Most pregnancies associated with thyroid disease will have a successful outcome. If the occasional at-risk fetus is to be identified and treated successfully there should ideally be close cooperation between obstetrician, endocrinologist and paediatrician.

Antithyroid Agents↗
PubMed1985

Free level monitoring of carbamazepine and valproic acid: clinical significance.

The recently available ultrafiltration technique facilitates determination of the free drug serum concentration of several antiepileptic drugs. For this reason a reappraisal of the clinical significance of free level monitoring was thought necessary. In this study on 203 patients receiving carbamazepine monotherapy and 101 patients receiving valproic acid monotherapy, the total and free drug levels were correlated with therapeutic outcome and side effects. Our investigations indicated no closer correlation between free concentration and seizure reduction or side effects than between total concentration and effectiveness or side effects. However, we found a close correlation between total and free concentrations.

Adolescent↗
PubMed1984

Lack of significant correlation between circadian profiles of valproic acid serum levels and epileptiform electroencephalographic activity.

Using mobile long-term electroencephalographic (EEG) monitoring in 7 absence epilepsy patients, the course of spike-wave discharge rate before and during valproate monotherapy was measured and compared to the profile of valproic acid serum level. Correlation analysis was done, taking into account an eventual time delay between drug concentration and effect on EEG. No significant correlation was found when comparing serum levels with the actual discharge profile or with the profile of changes in discharge rate.

Adolescent↗
PubMed1984

Intensive follow-up monitoring in patients with once daily evening administration of sodium valproate.

For 18 previously untreated patients with absence, myoclonic, or grand mal seizures--or combinations--results of clinical and electroencephalographical monitoring are reported. Sodium valproate was given once daily in the evening. Monitoring included repeated 24-48 h EEG recordings and drug blood level measurements. Results indicated the evening monodose to be an adequate therapeutic schedule for a considerable number of patients. Apart from the aspect of simplification, a further important aim is to individually minimize the drug dose. An average of 15.6 mg/kg sodium valproate (range, 10.0-25.5 mg/kg) per day was administered. In some cases the EEG discharge activity continued to be lowered even after the drug blood level had reached steady state. With medication, frequency and total duration of paroxysms were significantly lowered (by more than 90%) in over 80% of the patients, whereas the mean duration of paroxysmal activity did not change uniformly. Before treatment, short paroxysms (1-5 s) were seen together with longer ones in 11 patients. During treatment either all paroxysms disappeared or, in cases of remaining activity, most discharges were short and not accompanied by seizure manifestations. Blood level profiles over 24 h showed maximal values between midnight and 2 a.m. The minimal values (about half of the maximum) were found between 10 p.m. and midnight. The 8 a.m. value was 70-80% of the maximum. Only three patients complained of slight side effects (temporary drowsiness, loss of hair). Because of the simplified handling, the relatively low dose per day, and the few side effects, it seems possible that for primary generalized epilepsies once daily evening administration of sodium valproate is appropriate without diminishing the antiepileptic effect.

Adolescent↗
PubMed1984

Nightmares and trauma: a comparison of nightmares after combat with lifelong nightmares in veterans.

In this study the chronic traumatic nightmares of men who had been in combat were found to differ from the lifelong nightmares of veterans with no combat experience in that they tended to occur earlier in the sleep cycle, were more likely to be replicas of actual events, and were more commonly accompanied by gross body movements. Traumatic nightmares may arise out of varying stages of sleep and are not confined to REM sleep alone. The group with lifelong nightmares showed evidence of thought disorder on the Rorschach. The men with posttraumatic stress disorder had failed to psychologically integrate their traumatic experiences and used dissociation as a way of dealing with strong affects.

Combat Disorders↗
PubMed1984

[The spread and inhibition of epileptic processes, findings with the kindling model in the cat].

The study was undertaken to describe some characteristics of subcortical brain activity during the development of an experimentally induced seizure disorder in the cat, as well as to test inhibitory effects of caudate counterstimulation. A further objective was to assess the use of closed circuit TV monitoring for the evaluation of clinical symptoms in an experimental model of limbic epilepsy. The analysis of event related potentials, spectral coherences and phases was especially suitable in order to detect a gradual lowering of the seizure threshold during the establishment of a unilateral Nucl. amygdalae epileptic focus. The results demonstrated evidence for the proceeding importance of hippocampal involvement during the development of seizure activity originating in the ipsilateral amygdala. No evidence, however, could be found for the existence of inhibitory functions triggered by stimulation of the ipsilateral caudate nucleus. The simultaneous split-screen TV monitoring of EEG and partial complex symptoms proved to be a valuable tool for the documentation of seizure patterns during the kindling procedure.

Animals↗
PubMed1983

Effect of valproic acid treatment on spike-wave discharge patterns during sleep and wakefulness.

7 patients suffering from absences were recorded before antiepileptic treatment, in the early phase of valproate monotherapy and after having reached steady state. Recordings made with the Oxford-Medilog 4-channel cassette recorder were analyzed visually as well as by a computerized s-w pattern recognition approach, the latter facilitating quantification of pattern characteristics (number, amplitudes and duration of spikes and waves). Measurements were made separately for epochs of wakefulness and sleep. Compared to the premedication phase the amount of s-w discharges in 24 h showed an average reduction of more than 90%. For the majority of the patients, 24-hour discharge profiles showed a maximum in the early morning. Duration and amplitude of both spike and wave elements was higher during sleep. For the waking state, the ratio wave amplitude/spike amplitude was found to be increased under medication.

Adolescent↗
PubMed1983

[Psychomotor performance of schizophrenic patients and long-term neuroleptic therapy].

15 patients diagnosed as schizophrenics (ICD 295) under long-term neuroleptic treatment were compared with 15 neurotic and normal persons concerning their ability at a psychomotor task. There was no difference between both groups; no correlation between performance and neuroleptic dosage was found. However, motoric coordination of a small group was impaired. The authors discuss several hypotheses referring to these findings.

Adult↗
PubMed1980

[Functional relationship between central and peripheal motor signals. Use of averaging methods in epileptic problems (author's transl)].

For epileptic seizures with low-frequent and mild myoclinic components the existence of correlations between myoclonic and electroencephalographic activity is investigated. The method used is comparable to the evoked potential technique. The summation procedure is triggered by the occurrence of a pre-defined pattern in the peripheral recordings (EMG or acceletrometer) rather than by an external stimulus: 'Jerk-locked averaging' (JLA). Due to the small number of events it is necessary to control the validity of the results. For this aim, confidence intervals for the average signals are calculated. In three cases EEG-correlates have been found two of them showing spike-wave complexes in the EEG. The latency between the first positive spike and myoclonic activity was 12-14 ms and 22 ms, respectively. In the third case no spike pattern is found. JLA, however, shows a phase-locked relation between EEG and muscle activity. In order to interpret the findings different models of neuronal pathways are discussed. According to other studies a latency of 22 ms fits in with the concept of pyramidal activation, whereas latencies smaller than 15 ms are supposed to have subcortical origin spreading simultaneously toward cortex and subcortical efferent structures.

Adolescent↗
PubMed1980

[Spike waves pattern recognition in EEG long term registrations using a variably programmed laboratory computer].

The application of automatic approaches in EEG pattern recognition essentially has two aims: to increase the level of objectivity (by means of quantification) and to decrease the amount of diagnostic work (by means of data reduction). In this study a computerized spike-wave detection method is described, realized on a small laboratory computer (PDP 11/03) and especially designed for the analysis of long term registrations. The program is written in FORTRAN in order to provide a high level of flexibility. The user may easily modify it for his own purposes. Pattern recognition is based on the configuration of maxima and minima. Different degrees of digital filtering is used for spike analysis and wave analysis. The time codes of the events are registered and stored on magnetic disk. In a subsequent computer run the results may graphically be displayed or submitted to further analysis. An example is given testing in which way the results depend on the choice of the parameter set (duration and amplitude of spike and wave). The time course of the frequency of SW-events (or regular SW-sequences, respectively) are compared to the results of conventional analysis.

Computers↗