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Biomedical subjects

P Derambure

Publications and source records attributed to P Derambure.

48 records · Page 3Linked to original sources
PubMed1999

[Complete atrioventricular block during temporal lobe epilepsy. Apropos of a case].

The authors report the case of a 37 years old woman with no previous medical history, admitted to hospital for investigation of unexplained syncope, sometimes associated with generalised fits. After standard non-invasive cardiovascular investigations, no diagnosis could be made. The tilt test induced a minor syncopal episode without reproducing the clinical symptoms. In view of the discordance between the induced and spontaneous symptoms, a neurological opinion was requested. During the recording of an electroencephalogram, syncopal atrioventricular block was observed, preceded by auditory hallucinations, reproducing exactly the clinical symptoms. Analysis of the sequence of events showed the conduction defect to arise after the onset of the epileptic fit, indicating a diagnosis of syncopal complete atrioventricular block complicating cryptogenic temporal epilepsy, and requiring specific treatment. This case illustrates the importance of close collaboration between cardiologists and neurologists in the management of cases of unexplained syncope.

Adult↗
PubMed1998

Influence of chronic administration of L-DOPA on event-related desynchronization of mu rhythm preceding voluntary movement in Parkinson's disease.

The spatiotemporal pattern of event-related desynchronization (ERD) during the motor preparation period preceding a self-paced voluntary wrist-flexion was compared in two groups of 10 right and 10 left hemiparkinsonian patients, before and after chronic administration of L-DOPA. ERD was computed in the 9-11 Hz frequency band from 11 source derivations covering the medial frontocentral, central and parietocentral areas, during two successive left and right experimental conditions (100 self-paced wrist flexions). In the two groups ERD appeared with a shorter latency over the contralateral primary sensorimotor area, when the movements were performed with the akinetic hand. After L-DOPA administration, earlier ERD onset before the movement was observed in both groups over the contralateral and ipsilateral central and parietocentral areas. A medial frontocentral ERD distribution was also observed before the onset of movement, especially in the right hemiparkinsonian group. Delayed ERD onset, which shows that programming of movement is affected in Parkinson's disease, may be partially corrected by L-DOPA therapy.

Antiparkinson Agents↗
PubMed1997

Abnormal cortical activation during planning of voluntary movement in patients with epilepsy with focal motor seizures: event-related desynchronization study of electroencephalographic mu rhythm.

PURPOSE: The spatiotemporal distribution of EEG mu rhythm desynchronization was analyzed in patients with partial epilepsy to determine whether frequent focal motor seizures could induce a change of cortical activation during the planning of a voluntary movement. METHODS: The event-related desynchronization (ERD) of the mu rhythm was quantified during a self-paced voluntary movement of the thumb. The results were compared between two groups of patients with epilepsy: in one group (n = 12), the patients had frontal lobe epilepsy with frequent focal motor seizures (FMS); in the second group (n = 12), they had temporal lobe epilepsy (TLE) with complex partial seizures but no ictal movement disorder. The results were also compared with those of control subjects of same age (n = 10). RESULTS: In the control group, desynchronization of mu rhythm began over the contralateral central region 2,000 ms before the movement onset. In the FMS group, the desynchronization of mu rhythm was delayed, appearing only 500 ms before the movement onset, and the amplitude of ERD was increased over the frontocentral region. In the TLE group, the spatiotemporal pattern of ERD was the same as in normal subjects, but the amplitude of ERD was increased. CONCLUSIONS: These results indicate that there is a change of reactivity of mu rhythm in patients with partial epilepsy. The change in spatiotemporal pattern of ERD in patients with frequent focal motor seizures suggests that there is an abnormal cortical activation during the planning of a voluntary movement.

Adult↗
PubMed1995

[Effects of hypocaloric diet on respiratory manifestations in Willi-Prader syndrome].

BACKGROUND: Prader-Willi syndrome (PWS) is a multisystem disorder with hyperphagia and obesity. Breathing disorders such as snoring, sleep apnea syndrome, and sleep hypoventilation have also been reported. CASE REPORT: Jonathan was born with the typical features of PWS. He developed exercise dyspnea, cyanosis and nocturnal sweating at the age of 3 years. A few months later, a respiratory failure required his admission to the intensive care unit. His weight was then 48 kg (300% ideal body weight (IBW); physical examination showed polypnea (60 breaths/min), cyanosis, fat deposition on the chest wall. Transcutaneous oxygen saturation was 65%, carbon dioxide tension 81 mmHg (capillary sample). Pulmonary hypertension was found (mean arterial pulmonary pressure = 55 mmHg). Polysomnography detected hypoventilation with persistent hypoxemia increasing during the night and transient dips of oxygen saturation with bradycardia. He was treated with oxygen, mechanical ventilation (facial mask) and a low caloric diet (600 cal/day). Four months later, he weighed 33 kg (200% IBW); the respiratory features had resolved and gazometric values and pulmonary pressure returned to the normal ranges. Polysomnography showed only obstruction apnea and hypopnea without oxygen desaturation. CONCLUSIONS: Patients with PWS may develop respiratory symptoms sufficient by severity to be life threatening. They are related to morbid obesity and are influenced by a hypocaloric diet. Follow-up of patients with this syndrome must include repeated respiratory evaluation.

Child, Preschool↗
PubMed1994

Spatiotemporal study of Bereitschaftspotential and event-related desynchronization during voluntary movement in Parkinson's disease.

Bereitschaftspotential (BP) and Event-Related Desynchronization (ERD) were simultaneously recorded during a voluntary wrist flexion in 10 patients with Parkinson's disease (PD) treated with L-Dopa therapy and 10 control subjects. BP and ERD were analyzed 2 s before and 0.5 s after the movement, during two successive left and right experimental conditions. ERD (9-11 Hz) was computed from 11 source derivations (frontocentral, central, parietocentral). The BP was averaged from these 11 electrodes. For the BP, no spatiotemporal difference was found between the two groups. BP began bilaterally over the 3 groups of electrodes, 1250 ms before movement onset for the right flexion and 1500 ms for the left flexion. A contralateral predominance appeared 500 ms before movement onset over the central area. ERD began in the control group 1750 ms before movement over the contralateral central area, and then appeared bilaterally after its execution. In the PD group, the ERD appeared with a shorter latency than in the control group, 1250 ms (left flexion) and 1000 ms (right flexion) before movement onset; diffusion over the ipsilateral side was found 500 ms before movement onset. ERD also involved the frontocentral area and could be interpreted as a compensatory activity of the supplementary motor area. These findings suggest that with Parkinsonian and control subjects, ERD gives additional and maybe more information than the BP about changes of cortical activity during the motor preparation period. In the PD group the delay of ERD appearance seems to confirm that the programming of movement would be affected, thus explaining partially akinesia.

Aged↗
PubMed1993

Evaluation of event-related desynchronization (ERD) during a recognition task: effect of attention.

Event-related desynchronization (ERD) was studied in 10 subjects during a verbal recognition task. The attentional load of the task varied according to the difficulty to discriminate targets and distractors. The EEG recorded from 29 electrodes was used to compute ERD from 14 source derivations in 125 msec intervals and displayed as spatio-temporal maps. The results show that large brain areas of both hemispheres are significantly activated when the attentional load is high. This cerebral activation pattern is less pronounced when the load is low. ANOVA reveals main effects of attention and time and a significant interaction between attention and time.

Adolescent↗
PubMed1993

P300 component of the event-related potentials (ERP) during an attention task: effects of age, stimulus modality and event probability.

The effects of age, stimulus modality and event probability on event-related potentials (ERP) were studied in 12 young and 12 elderly healthy subjects. The ERP were recorded from 15 electrodes referred to linked ears. Results showed that both amplitude and latency of the P300 component are affected by aging. Study of the latency of the earlier ERP components in the two age groups revealed that the P300 delay was not imputable to a delay of the earlier components. P300 amplitude and latency were also affected by event probability and stimulus modality: infrequent stimulus involved higher and later P300, but this effect was more pronounced in the young than in the old group; higher and later P300 were also recorded during the visual task compared to the auditory. Topographical repartition of the brain wave revealed a predominance of the central sites (Fz, Cz, Pz). The findings are discussed in relation to the sensitivity of the ERP assessment procedures in age related modifications of information processing.

Acoustic Stimulation↗
PubMed1993

Effect of aging on the spatio-temporal pattern of event-related desynchronization during a voluntary movement.

Event-related desynchronization (ERD) of alpha components was studied in young and elderly subjects during planning of voluntary movement. ERD was quantified from 11 source derivations covering regions of the scalp corresponding to the supplementary motor area, the left and right primary sensorimotor areas, the vertex, and the medial posterior parietal cortex. Spatio-temporal display of ERD showed a very different pattern in elderly subjects, with mainly a spatial diffusion of ERD over the parietal and frontal regions. On the contrary, ERD in young subjects was limited to the central regions. ERD was also more lasting in elderly subjects. Changes of the ERD pattern in elderly subjects could indicate a change of cortical activation during voluntary movement. The data also confirm that ERD study is a useful electrophysiological exploration to observe the changes of cortical activation during cerebral aging.

Adult↗
PubMed1993

[Spatiotemporal study of event-related desynchronization during self-paced movement].

The desynchronization of Alpha band components during a self-paced movement of the thumb was studied in 7 subjects. The EEG was recorded from 23 electrodes located on the frontocentral, central, and parietocentral regions, referred to the right mastoïde, 4 s before and 2 s after movement onset. The data were then transformed to obtain 11 source derivations. The temporal evolution of the power of the signal within the Alpha band, every 250 ms, associated to the non parametric statistic test of Wilcoxon, authentifies the event-related desynchronization (ERD). The spatiotemporal analysis of ERD underlines on the central regions, two principal locations of ERD: one controlateral to the movement, starting more than 1 s before the movement; the other, ipsilateral, shorter, during the movement. However, no significance desynchronization was underlined on the vertex. The ANOVA used to analyse these results confirms the principal location of ERD on the central region, and seems to indicate a right lateralisation during the right or the left movement.

Adult↗
PubMed1993

[Topographical study of event-related desynchronization: value in the psychophysiologic approach to cognitive processes].

The interest of the event-related desynchronization study has already been evidenced, for example in the study of the cerebral activation modifications consecutive to cognitive processes. We observed here the evolution of this index during a recognition task where the material to memorize varied. Ten young subjects had to learn and then recognize a list of words or forms. The desynchronization of the alpha rhythm consecutive to each stimulus was recorded at 14 localizations on the scalp. We observed that the time evolution of the event-related desynchronization was different in each task. In the visual task, the phenomenon began sooner and was longer lasting. As long as the cortical area were concerned, any dominance nor interhemispheric difference were observed. During the visuospatial recognition task, the event-related desynchronization was however more widespread.

Adolescent↗
PubMed1990

Management of focal intracranial infections: is medical treatment better than surgery?

Three groups of patients with single hemispheric brain abscesses or subdural empyemas, from 1 to 5 cm large, with similar initial prognosis, have been treated either by medical treatment alone (20), aspiration (21), or excision (15). Differences in survival were not found, but medical treatment alone was better for long term sequelae. Surgical procedures (either aspiration or excision) were better for both isolation of the organism and the hospital stay before discharge. In spite of good results, it is unwise to conclude too strongly in favour of no surgical treatment as this study was not randomised.

Adult↗