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Biomedical subjects

J D Guieu

Publications and source records attributed to J D Guieu.

At least 19 recordsLinked to original sources
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↗
PubMed1994

[Surgical treatment of snoring and sleep apnea syndromes. Results apropos of 59 cases].

From 1991 to 1993, 59 patients underwent surgical cure for snoring. Polysomnography was performed 47 times when history taking and clinical signs revealed diurnal and nocturnal manifestations. Sleep apnea was confirmed in 20 patients with a mean apnea-hypnea index of 34.1. Treatment was based on surgery of the velum palatinum in 59% of the cases, the palatine tonsils in 39% and the basilingual tonsils in 1 patient. Snoring disappeared in 24 patients (40%) and improved for 75% satisfaction in 22 patients (37%).

Adult↗
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

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↗
PubMed1992

Motor evoked potentials to magnetic stimulation: technical considerations and normative data from 50 subjects.

Magnetic stimulation of the brain and cervical and lumbar spinal roots was performed on 50 healthy volunteers. Compound muscle action potentials (CMAPs) were recorded from biceps brachii, abductor digiti minimi (ADM), rectus femoris and tibialis anterior (TA). We assessed central conduction times by subtraction of peripheral from central latencies and compared results using either spinal root stimulation or the F-wave method. Side-to-side differences of total conduction time, peripheral conduction time and central conduction time (CCT) were measured and the effect of clockwise vs counterclockwise stimulations on latencies and sizes of CMAPs is emphasized. Amplitudes and areas of CMAPs were expressed as a percentage of the peripheral M response for ADM and TA. There was a positive correlation between CCT to the lumbosacral region and height, but not between the cervical region and height. No correlation was observed between genders and central conduction times, amplitudes or areas of CMAPs.

Action Potentials↗
PubMed1992

Control of tremor and involuntary movement disorders by chronic stereotactic stimulation of the ventral intermediate thalamic nucleus.

The authors report on the long-term results of chronic stereotactic stimulation of the ventralis intermedius thalamic nucleus performed in 14 cases of disabling and intractable tremor. There were 10 patients with parkinsonian tremor and four with essential tremor. Three of the 10 parkinsonian patients had previously undergone contralateral thalamotomy. Tremor was assessed by clinical evaluation, surface electromyography, accelerometer, and videotape recordings before and after stimulation. The deep-brain electrode was implanted in the ventralis intermedius nucleus according to stereotactic procedure and connected to a subcutaneous pulse generator after a stimulation test period. Tremor suppression or reduction was obtained in all cases with high-frequency (130 Hz) stimulation. Marked functional improvement was maintained in 11 patients with a mean follow-up interval of 17 months. Levodopa-induced dyskinesias observed in five parkinsonian patients prior to surgery were improved or suppressed in four cases by thalamic stimulation. Stimulation was continued during the day and stopped at night in eight cases. Six patients were stimulated night and day to avoid a rebound effect which appeared as soon as the pulse generator was stopped. The only side effects were hand tonic posture in one case and persistent paresthesia in another case. The mechanism of action of this attractive treatment may be a functional alteration of the thalamic discharging area. The authors conclude that this technique is a good alternative to thalamotomy, especially when the risks of high-frequency coagulation are severe in frail and older patients.

Adult↗
PubMed1991

[Chronic sciatalgia caused by sensitive deafferentiation following surgery for lumbar disk hernia: clinical and therapeutic aspects. Apropos of 110 patients].

Sensitive deafferentation is a well recognized entity which has changed the therapeutic approach of some kinds of chronic post operative sciatalgia. It mainly occurs related with a long story of radicular pain and the responsibility of so-called epidural fibrosis has to be discussed. The case records of 110 consecutive patients with deafferentation sciatalgia were reviewed and the clinical data precised: chronic and lasting burning pain with acute nightly paroxysms and sensitive alterations at objective examination. Neuroradiological explorations eliminated the possibility of recurrent disc herniation and neurophysiological tests assessed the chronic radicular suffering and the degree of lemniscal degeneration. After medical treatment (analgesic drugs with central tropism), a strict clinical assessment of pain intensity allowed optimal choice of the technique of neurostimulation: transcutaneous electrical stimulation (51 patients) and/or spinal cord stimulation (59 patients). The efficacy of transcutaneous stimulation (40 excellent and good results) was most often related to its continuous utilisation with a short post-effect. Its side-effects and the frequency of multiradicular involvement lead to spinal cord stimulation. With a mean follow-up period of 37 months, the pain relief was considered as excellent in 51.5%, good in 38% and poor in 8.5% of the patients. One patient had a negative test and was not definitively implanted. Another case failed to respond to stimulation. The clinical and technical complication of the method are reported.

Adult↗
PubMed1991

[Right unilateral auditory agnosia following left lenticular hemorrhage].

A 33-year old patient who had had left lenticular hemorrhage presented with an inability to understand with the right ear oral language and, in a less dramatic way, nonverbal sounds. This unilateral auditory agnosia was first associated with a right motor underutilization and right motor, sensitive, visual and auditive extinctions. Speech discrimination scores were 100% with the left ear and 15% with the right ear, even less in dichotic conditions. Tonal audiogram, as well as early and late components of the auditory evoked potentials were normal. Cerebral regional perfusion and metabolism were impaired over the left parietotemporal area. There was severe hypoactivation of the left hemisphere with right monaural verbal stimulations. Rehabilitation consisting of non-specific attention tasks and repetitions of words reaching only the right ear was undertaken 15 months after the stroke. The oral language comprehension improved, as did the left hemisphere activation, and the extinction phenomena disappeared, except for the auditory one. The unilaterality of the auditory agnosia could be due, in part, to a peculiar physiological processing in this patient, such as poor performance of his right ipsilateral auditory pathway which could be improved with practice. A striatal lesion could induce a spatial hemi-inattention as reflected by the multimodal extinction in this case. Besides, a lack of selective activation for verbal stimulation of the left hemisphere is suggested.

Adult↗
PubMed1991

[Hereditary parkinsonism-dystonia syndrome of juvenile onset with diurnal fluctuations].

Symptoms of fluctuating dystonia developed in 4 subjects of the same family during childhood or adolescence. In the 2 sisters, these symptoms were initially or subsequently associated with signs of parkinsonism, whereas in the 2 brothers they disappeared, spontaneously in at least 1 case, and signs of parkinsonism appeared later after a free interval. Anticholinergic agents and L-Dopa proved very effective against all extrapyramidal signs. These cases are similar to those gathered by Nygaard et al. in 1988 under the term "Dopa-responsive dystonia". Yet laboratory data seem to confirm that the common physiological mechanism is a disorder of tetrahydrobiopterin metabolism. Serum and urinary biopterin levels were lowered in our 4 cases but were normal in an unaffected sister. However, like the subjects affected this third sister showed a decrease of platelet serotonin which was taken as being a consequence of aromatic aminoacid hydroxylation defect due to tetrahydrobiopterin deficiency.

Adolescent↗
PubMed1990

[Spinal cord ependymoma: contribution of MRI using gadolinium].

In a case of panmedullary ependymoma, a rare tumour, MRI was performed before and after gadolinium injection. The latter clearly demonstrated the borders of the tumour. Throughout the procedure, neurophysiological exploration was carried out with recording of motor and somatosensory evoked potentials.

Adult↗
PubMed1989

[Acute spinal amyotrophy in toxoplasmosis].

A 19 year-old man developed an acute syndrome of the anterior horn of cervical spinal cord during a primo-infection with toxoplasma. The neurological syndrome was completely regressive after treatment with 1 600 mg/day of trimethoprim-sulfamethoxazole for three months.

Acute Disease↗
PubMed1989

[Functional and motor study of retrosternal esophageal plasties].

The stomach may be used for esophageal reconstruction after resection of esophageal cancers. The aim of this study was to assess the motility of retrosternal esophagoplasty (RO) following the Akiyama procedure in 6 men (mean age: 56.7 years), at least two months after surgery by means of two techniques: a) manometry of the transplant with a multilumen perfused catheter in 50 and 40 cm from the incisor teeth including spontaneous (5 min) and poststimulation recordings, b) an isotopic method for assessing the gastric emptying of a meal labelled with 111In for the liquid phase and with 99mTc for the solid phase, compared to 12 volunteers as controls. Baseline pressure was 11.2 +/- 2.4 H2O cm without spontaneous activity. After dry and wet deglutition (5 ml of water), 6 patients showed synchronous rise in pressure, having mean amplitude of 12.7 +/- 2.3 cm H2O and lasting 4.3 +/- 1.2 s. Liquids T1/2 was 16.2 +/- 7.8 min in controls (p less than 0.01) and solids T1/2 was 17.7 +/- 6.4 min vs 61.7 +/- 16.5 min (p less than 0.001). The lack of propagated activity associated with rapid emptying of the meal through the plasty with no discrimination between solids and liquids suggests that RO does not participate actively in digestion.

Deglutition↗
PubMed1987

[Mechanisms of diabetic impotence. 25 cases].

Twenty-five impotent diatetics were investigated by means of nocturnal penile tumescence monitoring, hormone determinations, penile blood pressure measurement, artificial erection test and dynamic cavernosography, bulbocavernous reflex latency time measurement and cortical evoked responses from pudendal nerves. Sexological treatment was then attempted for a better evaluation of the psychogenic element. Penile blood pressure was also measured in 15 non-impotent diabetics and was found to be abnormal as often as in impotent diabetics. The results as a whole demonstrated that impotence was predominantly psychogenic in 9 cases, predominantly organic in 12 cases and mixed psychogenic and organic in 4 cases. Diabetic impotence is often due to several causative factors, as was the case in 12 of our patients. The factors most frequently responsible were psychological (present in 13 cases), neurological (present in 12 cases) and vascular factors (arterial abnormalities in 7 cases, "venous leakage" in 4 cases). Endocrine abnormalities were observed in only 2 cases.

Diabetes Complications↗
PubMed1986

Venous incompetence: critical study of the organic basis of high maintenance flow rates during artificial erection test.

We tested whether the necessity for high flow rates of saline to maintain an artificial erection actually corresponds to an organic abnormality able to induce impotence as claimed recently. A total of 56 patients with presumed vascular impotence and 13 with typical psychogenic impotence underwent dynamic cavernosography followed by the artificial erection test. The former 56 patients also underwent bilateral selective internal iliac arteriography. A severely elevated maintenance flow rate (more than 120 ml. per minute) was found in 19 of the 56 patients with vascular and none of the 13 with psychogenic impotence, while a moderately elevated maintenance flow rate (80 to 120 ml. per minute) was found in 11 and 3, respectively. In most cases a severely elevated maintenance flow rate was associated with arterial (16 patients) or neurological abnormalities able to disturb erection. However, a severely elevated maintenance flow rate seemed to correspond to an organic abnormality able to induce impotence or to worsen erectile failure induced by other organic factors. Indeed, we found no severely elevated maintenance flow rates among our 13 patients with psychogenic impotence and the nocturnal penile tumescence test was normal in only 1 of 12 tested patients, although 7 had no other organic impairment sufficient to induce impotence (only moderate arterial stenoses in 4). In addition, sexual treatment succeeded in only 1 of the 13 patients, while our success rate is 43 per cent among patients with arterial impotence exclusively and this treatment succeeded in 6 of 10 patients with a moderately elevated maintenance flow rate. On the contrary, a moderately elevated maintenance flow rate does not seem to correspond to a genuine organic abnormality able to induce impotence. Indeed, we found it in 3 of 13 patients with psychogenic impotence, and every patient with a moderately elevated maintenance flow rate and normal arteries had a normal nocturnal penile tumescence test or was cured by sexual therapy. In conclusion, a maintenance flow rate exceeding 120 ml. per minute seems to reveal a genuine venous incompetence but in most cases this abnormality is only the cofactor of an arterial obstruction.

Erectile Dysfunction↗
PubMed1985

Comparative investigations in 26 impotent and 26 nonimpotent diabetic patients.

To determine the causes of diabetic impotence the same investigations were performed in 26 impotent and 26 nonimpotent diabetics. The rates of abnormalities found were almost identical in the 2 groups in regard to Doppler examination of the penile arteries, conduction velocities of the median nerves, latency times of the bulbocavernosus reflex and cystometrograms. Conversely, urine flow rates (24 of 25 versus 2 of 26 patients) and Minnesota Multiphasic Personality Inventory (14 of 23 versus 0 of 14 patients) were almost exclusively abnormal in the impotent diabetics. In addition, inadequate sex-specific attitudes were found in 60 per cent of the impotent diabetic men, which was the proportion found in a carefully selected sample of psychogenically impotent nondiabetic men. The distribution of the abnormalities found suggests that in most diabetic patients impotence results from the addition of a subtle abnormality of the autonomic nervous system in almost every case or psychological and arterial factors.

Adult↗