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Biomedical subjects

J D Guieu

Publications and source records attributed to J D Guieu.

At least 37 records · Page 2Linked to original sources
PubMed1999

Motor programming is more affected in progressive supranuclear palsy than in Parkinson's disease: a spatiotemporal study of event-related desynchronization.

To determine the benefit of motor programming analysis for distinguishing patients with parkinsonism, we compared the spatiotemporal pattern of event-related desynchronization (ERD) preceding a self-paced voluntary wrist flexion between two groups of 10 patients with progressive supranuclear palsy (PSP) and Parkinson's disease (PD) and 10 control subjects. ERD of the mu rhythm was computed from 11 source derivations covering the medial frontocentral, central, and parietocentral areas during two successive left and right experimental conditions (80 self-paced wrist flexions). ERD began in the control group 1750 ms before movement onset over the contralateral central area and then appeared bilaterally on movement execution. In both patient groups, spatiotemporal distribution differed from that in the control group. In the PSP group, ERD had a shorter latency over the contralateral primary sensorimotor area compared with the PD group (PSP: 375 ms before movement onset for both conditions; PD: right flexion 1125 ms before movement onset, left flexion 1000 ms). ERD was observed over the parietocentral area in both groups but also with a clear reduction of latency before movement onset in the PSP group. In both groups, a bilateral central pattern appeared 250 ms before movement execution. In conclusion, our study indicates that ERD analysis is a useful method for observing the changes in cortical activation and for measuring motor programming impairment in parkinsonism, which was more affected in PSP than in PD.

Aged↗
PubMed1999

Are prescribed medications effective in the treatment of insomnia complaints?

Although frequently investigated in the general population, the epidemiology of insomnia complaints and their treatment have received little attention in general practice. This study recruited patients > or =15 years of age, consecutively, from 127 general practitioners in France. The physicians collected data from 11,810 of their patients, of whom 55.5% were women. Insomnia complaints were reported by 26.2% (25.4% to 27%) of the sample and use of sleep-promoting medication by 10.1% (9.7% to 10.7%). About 47% of the prescribed drugs used were anxiolytics and 45% hypnotics. Most consumers took sleep-enhancing drugs on a daily and long-term basis and most reported that the medication improved their quality of sleep. However, few distinctions emerged between elderly drug-taking insomniacs and elderly nontreated insomniacs with respect to the various dimensions of sleep. Results underscore the persistent general tendency among French general practitioners to overprescribe anxiolytics for the treatment of insomnia complaints and that they do so on a long-term basis, despite the findings of numerous studies showing that benzodiazepines are ineffective in the treatment of sleep complaints over the long term.

Adolescent↗
PubMed1999

[Event-related desynchronization and synchronization. Reactivity of electrocortical rhythms in relation to the planning and execution of voluntary movement].

Cortical electroencephalographic rhythms reactivity may be quantified using event-related desynchronization (ERD) and synchronization (ERS) methods. We therefore studied cortical activation occurring during programming and performance of voluntary movement in healthy subjects. EEG power evolution within the reactive frequency bands (mu and beta central rhythms) was averaged before, during and after a minimum of 50 self-paced flexions of the thumb. Recordings in 18 normal adults showed that ERD (decrease in power) of mu rhythm started 2,000 ms before movement onset, while ERD of beta rhythm started 1,500 ms before movement onset. Early ERD of mu and beta rhythms were located over the contralateral central region covering primary motor cortex. They were followed by bilateral ERD occurring over ipsilateral and contralateral central regions during performance of the movement. At the end of the movement, an ERS (increase in power) of beta rhythm occurred. These results suggest that programming of voluntary movement induces early activation in contralateral sensorimotor areas, while performance of the movement induces bilateral activation in sensorimotor areas. ERS of beta rhythm occurring at the end of the movement could correspond to inactivation of motor areas activated by movement. Based on EEG activity, ERD and ERS prove to be useful methods to analyze cortical activation during programming and performance of voluntary movements with good spatial and temporal resolution.

Adult↗
PubMed1999

[Event-related desynchronization and Parkinson disease. Importance in the analysis of the phase of preparation for movement].

This study was aimed at determining the spatiotemporal distribution of event-related desynchronization (ERD) during self-paced voluntary movement in order to establish the interest of this method for the analysis of movement programming in Parkinson's disease. Desynchronization of mu rhythm was recorded 2 s before to 0.5 s after right then left self-paced voluntary wrist flexions from 11 leads covering the primary sensorimotor cortex (central), supplementary motor area (frontocentral) and parietal cortex (parietocentral). Recordings were obtained from ten control subjects, ten patients treated for Parkinson's disease (bilateral symptoms) and 20 patients presenting with right or left hemiparkinsonism before and after chronic administration of L-dopa. In the control group, ERD started over the contralateral primary sensorimotor cortex 1,750 ms before movement and was bilateral just before performance of the movement. In both treated and de novo Parkinson's disease groups, decrease in ERD latency (1,000 to 1,250 ms before movement) was only observed when movements were performed with the akinetic hand and corresponded to a decrease in motor cortical activity. This confirmed that programming of movement is affected in Parkinson's disease. Earlier ERD with central ipsilateral distribution were also observed, suggesting that other cortical areas might be activated to compensate for dysfunction of movement programming and to increase the level of cortical activity required for performance of the movement. The administration of L-dopa to de novo hemiparkinsonians patients resulted in increased ERD latency over contralateral and ipsilateral central areas. As in the treated Parkinson's disease group, frontocentral ERD could also be recorded. L-dopa would thus partially restore the affected motor programmation and modulate cortical activation in both supplementary motor area and primary motor cortex, the later receiving more afferences from basal ganglia.

Antiparkinson Agents↗
PubMed1999

Comparative study of propofol and midazolam effects on somatosensory evoked potentials during surgical treatment of scoliosis.

OBJECTIVE: Studies of the effects on lower-limb cortical somatosensory evoked potentials (CSEP) during total intravenous anesthesia are sparse for propofol and are lacking for midazolam. This study was designed to compare the effects of propofol and midazolam on CSEP under total intravenous anesthesia during intraoperative monitoring for surgical treatment of scoliosis. METHODS: CSEPs were recorded in two groups of 15 patients during posterior instrumentation for treatment of idiopathic scoliosis. The anesthesia used the combination of atracurium, alfentanil, and an hypnotic agent (propofol for Group I or midazolam for Group II). The main characteristics of the CSEPs (P40 latency and N34-P40 and P40-N50 amplitudes) were recorded using ankle posterior tibial nerve stimulation. The CSEPs were recorded before induction, 10, 70, 100, 130, and 160 minutes after induction, and before the wake-up test. The statistical analysis involved analysis of variance for repeated measures. Both groups were homogeneous before induction. RESULTS: Neither CSEP deterioration during risk-associated surgical procedures nor postoperative clinical abnormalities were observed. Both propofol and midazolam induced increases in P40 latencies, with the increases being greater and more regular for the propofol-treated group. The amplitude values changed with time for both groups, decreasing mainly after induction; in the midazolam-treated group, the amplitudes were smaller but more stable. Propofol modified the morphological characteristics of the response by decreasing the late P60 component amplitude; the W-shaped CSEP morphological pattern was maintained with midazolam. CONCLUSION: This study demonstrates the appropriate use of either propofol or midazolam in scoliosis monitoring. Preoperative small-amplitude CSEPs might favor the use of propofol anesthesia.

Adolescent↗
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↗
PubMed1998

[Neuromonitoring and anesthesia in surgery of the spine].

The authors report the main effects of anaesthetic drugs that are used alone or in association with anaesthetic protocols on somatosensory evoked potentials (SEP) and on motor evoked potentials (MEP). In the first part of the article, the effects are analysed on SEPs and MEPs that are obtained from non-invasive methods; in the second part, the effects of anaesthesia are analysed with respect to invasive methods of EP recordings. The current increase of invasive techniques of neuromonitoring by SEPs and MEPs is in relation with the weak effect of anaesthetics on evoked responses. Total intravenous anaesthesia (TIVA) provides stable anaesthesia for non-invasive SEP neuromonitoring only if bolus is avoided. With TIVA and other anaesthetic techniques, the introduction of repetitive stimulation provides new possibilities for non-invasive MEP neuromonitoring.

Analgesics, Opioid↗
PubMed1998

Comparison of the effects of zolpidem and flunitrazepam on sleep structure and daytime cognitive functions. A study of untreated unsomniacs.

The effects of zolpidem 10 mg, flunitrazepam 1 mg, and placebo, administrated at bedtime, were studied in 12 healthy male insomniac patients. The assessments included polygraphic sleep recordings during the night and a battery of cognitive tests (sign crossing test, dichotic listening test, digit span test, visual recognition test and free recall test during four times during the following day. Compared with placebo, both active drugs improved sleep parameters. However, with zolpidem, the results were not statistically different from placebo. Zolpidem dit not alter sleep architecture in contrast to flunitrazepam, which significantly increased stage 2 and decreased slow wave sleep and REM sleep. No significant interaction was found between time of day for the evaluation of cognitive function. Flunitrazepam significantly impaired attention and memory compared with zolpidem and placebo, while zolpidem did not differ from placebo. These results indicate that zolpidem 10 mg preserved sleep structure and daytime cognitive functions in contrast to flunitrazepam.

Adult↗
PubMed1998

["Primary" orthostatic tremor. 10 clinical electrophysiologic observations].

Orthostatic tremor is an unusual kind of potentially disabiling tremor appearing immediately when standing. Clinical examination is normal in primary form except for wide base standing and unsteadiness which disappear when walking. Arm tremor resembling essential tremor is found present in one third of cases. Electrophysiological exploration is necessary for diagnosis and shows a regular rapid tremor (frequency around 16 Hz). We present 10 new cases, 3 men and 7 women, 37 to 74 years old. Unsteadiness when standing was the predominant complaint in 9 cases, the other first described pains in the lower limbs. All had visible or palpable tremor predominant in thighs. Four patients had postural arm tremor, one had neurogen syndrome in the lower limbs corresponding to toxic polyneuropathy which developed after tremor. Electromyographic study found high frequency (13-17.3 Hz) rhythmic discharge in weight-bearing muscles. Orthostatic tremor cannot be considered as a clinical variant of postural essential tremor. Its pathophysiology is unknown but the efficacy of clonazepam, primidone or barbiturates suggests the impairment of the gabaergic system.

Adult↗
PubMed1997

[Gastroesophageal reflux and esophageal motility disorders in infants with vagal hyperreflectivity presenting severe syncope].

AIM: The aim of the study was to evaluate the prevalence of gastroesophageal reflux and abnormalities of esophageal motility in a population of neonates referred for apparently life threatening event (ALTE) and presenting vagal hyperreflectivity. POPULATION AND METHODS: The study included 17 infants, who were examined after an ALTE. They were admitted at a mean age of 11.7 weeks (range 1-40 weeks). Vagal hyperreflectivity was confirmed in each infant by oculocardiac reflex. Before treatment, 24-hour intraesophageal pH-monitoring and esophageal manometry were performed. RESULTS: pH-monitoring and esophageal manometry were both normal in only two patients. pH-monitoring showed pathological reflux (% of time with pH < 4 more than 4.8%) in 10/17 (59%) patients. Manometric studies showed esophageal dysmotility in 12/17 (71%) of patients. Hypertensive lower sphincter was noted in 11/17 (65%) infants. Patients with normal manometry were older than patients presenting with esophageal dysmotility (P < 0.05). CONCLUSION: This study shows a high frequency of gastroesophageal reflux and dysmotility in infants with vagal hyperreflectivity. Hypertensive lower esophageal sphincter as well as vagal hyperreflectivity may correspond to dysmaturity of autonomous nervous system and facilitate the occurrence of ALTE.

Esophageal Motility Disorders↗
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↗
PubMed1997

Hereditary chin trembling or hereditary chin myoclonus?

Hereditary chin trembling is a rare autosomal dominant disease often considered as an "essential tremor variant". The clinical and neurophysiological data obtained in a new white family lead to the suggestion that this abnormal involuntary movement is a focal variant of hereditary essential myoclonus.

Adult↗
PubMed1996

Sympathetic skin response and R-R interval variability in multiple system atrophy and idiopathic Parkinson's disease.

We compared autonomic function in patients with multiple system atrophy (MSA) or with idiopathic Parkinson's disease (IPD) by measuring sympathetic skin response (SSR) and R-R interval variability (RRIV). SSR was investigated in 26 patients (13 with MSA and 13 patients with IPD). RRIV during deep breathing, Valsalva maneuver, and on standing was investigated in 20 patients (nine with MSA and 11 with IPD). MSA and IPD patients had similar age, illness duration, and therapy. Abnormal SSR was more frequent in MSA (69%) than in IPD (7.7%; x2, 10.4; p < 0.002). RRIV during deep breathing and the Valsalva maneuver was lower in MSA than in IPD (p = 0.02). RRIV during standing up was not significantly different in IPD and MSA. These differences between MSA and IPD may be due to more severe and widespread autonomic disturbance in MSA, related to more severe neuropathologic involvement of the autonomic nervous system. SSR and RRIV may aid in the differential diagnosis of parkinsonism and help to exclude from clinical trials MSA patients clinically misdiagnosed as having IPD.

Aged↗
PubMed1996

[Hypoxic-ischemic encephalopathy of the full term newborn. Contribution of the electroencephalogram and trans-fontanelle echography to the prognostic evaluation. Report of 29 cases].

This study was aimed at assessing by EEG recording and cranial imaging the cerebral function of 29 full term newborns presenting with hypoxic-ischemic encephalopathy and at establishing a correlation between the results and the neurological outcome. A correlation between the Sarnar's classification and the neurological outcome was observed, except for the intermediate grade. In this case, impairment of the EEG was variable and neurological prognosis was sometimes evidenced by cranial imaging. Unfavorable neurological outcome occurred when thalamic lesions were present, independently of clinical signs and EEG abnormalities.

Brain Ischemia↗
PubMed1996

Movement related desynchronisation pattern preceding voluntary movement in untreated Parkinson's disease.

OBJECTIVE: To study planning of movement in Parkinson's disease. METHODS: The spatiotemporal pattern of movement related desynchronisation (MRD) preceding a self paced voluntary wrist flexion was compared between two groups of 10 untreated right and left hemiparkinsonian patients receiving no treatment and 10 control subjects. The MRD was computed in the 9 to 11 Hz frequency band from 11 source derivations covering the frontocentral, central, and parietocentral areas, during two successive left and right experimental conditions. RESULTS: In the two patient groups the desynchronisation appeared over the primary sensorimotor area contralateral to the affected side with a shorter latency (750 ms before movement onset for the right hemiparkinsonian group and 875 ms for the left hemiparkinsonian group) than in the control group (1750 ms), only when the movements were performed with the akinetic hand. For the non-affected hand, the same latency as in the control group was noted (1750 ms). CONCLUSION: The delay of appearance of MRD in Parkinson's disease confirmed that the programming of movement is affected, thus partially explaining akinesia.

Aged↗
PubMed1995

Event-related desynchronization (ERD) patterns during memory processes: effects of aging and task difficulty.

Event-related desynchronization (ERD) was studied in 10 young (mean age = 19.1) and 10 older (mean age = 62.8) subjects during two recognition tasks: verbal and visuo-spatial. The difficulty of these tasks varied according to the difficulty to distinguish between targets and distractors. EEGs recorded from 29 electrodes were used to compute ERDs from 14 source derivations in 125 msec intervals. Thereafter, they were displayed as spatio-temporal maps. The results show that desynchronization was more widespread in the visuo-spatial compared to the verbal task. This was observed in the two age groups, although it was more pronounced in the young subjects. The effect of task complexity was also influenced by the kind of material to be remembered: more differences between the two levels of difficulty were observed during the verbal task. The results revealed significant influences of the task and time variables on the ERD patterns. A distinct time course of the desynchronization phenomenon was observed to be related to the kind of recognition task. Age and task complexity interacted with the other variables.

Adolescent↗