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Biomedical subjects

J Courjon

Publications and source records attributed to J Courjon.

At least 19 recordsLinked to original sources
PubMed1989

[The French Society of EEG and Clinical Neurophysiology is 40 years old].

The historical reminder of the foundation of the French EEG Society and the changes which have occurred during its operation show the worry of the Society for a better efficiency all along this last fourty years. A general survey of the scientific activities disclose the contribution of the society in the papers first published in the Revue Neurologique, and, after 1971, in the Revue d'EEG et de Neurophysiologie clinique de Langue française. The French participation in other clinical neurophysiological or scientific meetings in France and abroad is underlined by the important role it has played in the life of the International Federation for EEG Societies. Training of specialized doctors and technicians in the domain of the functional exploration of the nervous system has been a standing preoccupation of the Society, with the teaching of the so-called "Attestation d'EEG" in French universities and the training of technical personnel in specialized schools.

Electroencephalography↗
PubMed1986

[Visual, early auditory and somatosensory evoked potentials in multiple sclerosis (917 cases)].

Visual (VEP), brainstem auditory (BAEP) and somatosensory (SEP) evoked potentials were recorded over a 6 year period in 917 patients with or suspected of multiple sclerosis according to Mc Alpine's criteria. Evoked potentials provided information of diagnostic relevance in detecting clinically unsuspected lesions (spatial dissemination). They also gave valuable informations in patients with atypical or borderline clinical features. When abnormal, VEP indicated clinically silent lesions in 45.1 p. 100 of patients with definite MS, 66 p. 100 of those with probable MS and 78 p. 100 of the possible MS. Less than 15 p. 100 of SEP and/or BAEP abnormalities were found in 83 patients with a simple or recurring retrobulbar optic neuritis. Thirteen patients with acute transverse myelopathy and no prior history of neurological disease were studied. All had normal visual and brainstem auditory evoked potentials. Abnormal VEPs helped to the clinical assessment of 88 patients with progressive spastic paraparesis 46,6 p. 100 of whom had abnormal VEPs demonstrating disseminated lesions and 36,1 p. 100 had abnormal BAEPs. The frequency of the various types of VEP, BAEP and SEP abnormalities was studied as well as their course on repeated recordings. Results of multivariate analysis are given. It was found that the longer the time interval between the first MS relapse and the evoked potential recording, the higher the incidence of abnormalities. The incidence of evoked potentials abnormalities was lower in patients with normal CSF and higher in patients with inflammatory CSF. The abnormalities were more frequent when patients had clinical evidence of lesions of the sensory pathways explored by the tests.

Adolescent↗
PubMed1985

[Changes in the semeiology of epileptic seizures after status epilepticus: apropos of 65 cases].

In 65 patients with status epilepticus, we compared the clinical expression of isolated seizures and of status seizures. In 22 patients there was no relationship between status and isolated seizures. In addition the number of partial status is greater than that of partial seizures. In 9 patients, the type of seizures was modified after the status. From these results, status epilepticus seems to favor the eruption of secondary epileptogenic focuses, generally transitory.

Adolescent↗
PubMed1984

[Status epilepticus in adult epileptics followed in a neurologic hospital].

One or several status were observed in 90 chronic adult epileptics. Partial status, especially motor and of similar type, is rare in the clinical course of usual partial epilepsy. Generalized status, chiefly petit mal (PM) status, appears in more severe generalized epilepsies. Partial status epilepticus is observed in motor attacks and rarely in partial complex epilepsies, although the latter are more frequent. In 40% of cases the aetiology is unknown. Delay of the first status is variable, from 2 to 30 years. Status does not make previous epilepsy worse. Generalized status, mainly PM status, appears in patients with absences and generalized attacks, sometimes some decades after the beginning of the disease. In half of the cases PM status are frequent but are sometimes the only expression of the epilepsy.

Adolescent↗
PubMed1984

[Treatment of partial motor status epilepticus in adults with intravenous diphenylhydantoin (DPH). Prospective study of 50 cases].

Fifty adult patients with partial motor status epilepticus were treated with a single intravenous (i.v.) injection of diphenylhydantoin (DPH), 20 mg/kg body weight at a rate of 1 mg/kg/min. Seizures were controlled in 32 patients (64%) during the injection or within the following hour; in 13 of them previous (i.v.) injections out of benzodiazepines had been ineffective. DPH was effective in 10 patients of 11 with a previous history of epileptic seizures and without problems of consciousness during their epileptic status. In contrast, 13 failures out of 18 concern occasional status in patients deeply comatose because of head trauma, neurosurgical operation or intracerebral hemorrhage. Total plasmatic levels of DPH, when measured 24 h after the injection, were found between 38 mumol/l in all patients, and were in the range of 40 mumol/l-100 mumol/l in 77% of cases. Adverse effects were: pain at the injection site (6 cases), horizontal nystagmus during injection (5 cases), transient cerebellar symptoms (3 cases). This study confirms that single loading doses of DPH can maintain DPH plasmatic levels within the therapeutic range during 24 h, with minor or transient side effects, provided that cardiovascular contra-indications are respected.

Adult↗
PubMed1984

[Contribution of visual evoked potentials (VEP) to neurology].

It is widely admitted that visual evoked potentials (VEPs) are clinically useful for diagnostic purposes in multiple sclerosis (MS). Delayed P100 component to pattern shift stimulation indicates a dissemination of the demyelinating process when routine ophthalmological investigations are normal. The delay of P100 may be observed early in the course of the disease following an attack of optic neuritis (ON); in the absence of previous ON the P100 latency may appear later after the onset. The P100 latency exceptionally returns to normal values. Compared with somatosensory or brain-stem auditory evoked potentials VEPs are the most efficient for the detection of silent lesions in MS. Longitudinal studies demonstrate that the percentage of MS patients with abnormal VEPs increases with time during the course of the disease. Delayed P100 component may also be recorded in patients with heredodegenerative or toxic optic neuropathies, but the clinical context is very different. The detection of bitemporal visual field defects with VEPs is more uncertain. In patients with cortical blindness VEPs may persist. When compared with usual campimetric investigations, VEPs do not represent a simple and reliable means of investigating lateral homonymous hemianopsia.

Epilepsy↗
PubMed1983

Dissociation of early SEP components in unilateral traumatic section of the lower medulla.

Spinal and scalp early SEPs were recorded, using a noncephalic reference electrode, in a patient with a traumatic cervicomedullary lesion causing unilateral loss of position sense. Cervical N11 and N13 and scalp-recorded far-field P14 SEPs were clearly dissociated following stimulation of the affected side. The findings suggest that the P14 component is generated above the foramen magnum, whereas the cervical N13 has a spinal generator.

Adult↗
PubMed1983

Neural generators of N18 and P14 far-field somatosensory evoked potentials studied in patients with lesion of thalamus or thalamo-cortical radiations.

Somatosensory evoked potentials (SEPs) to electrical stimulation of the right or left median nerve were studied in 4 patients with hemianesthesia and a severe thalamic or suprathalamic vascular lesion on one side. The SEPs were recorded with a non-cephalic reference. The normal side of each patient served as his or her own control. The lesion consistently abolished the parietal N20-P27-P45 and the prerolandic P22-N30 SEP components. It did not significantly affect the P9-P11-P14 positive far fields, nor the widespread bilateral N18 SEP component. This allowed N18 features to be studied without interference from cortical components. It is proposed that N18 reflects several deeply located generators in brain stem and/or thalamus whereas N20 represents the earliest cortical response of the contralateral post-central receiving areas.

Brain Mapping↗
PubMed1983

Astereognosis and dissociated loss of frontal or parietal components of somatosensory evoked potentials in hemispheric lesions. Detailed correlations with clinical signs and computerized tomographic scanning.

Detailed clinical sensory and motor signs were correlated case by case with somatosensory evoked potentials (SEP) in 22 selected patients with a single circumscribed hemisphere lesion. The lesions collectively mapped out a variety of cerebral sites from the anterior frontal to the posterior parietal regions. SEPs were averaged from 8 standard scalp sites with an earlobe reference electrode, so that parietal N20-P27-P45 were differentiated from prerolandic P22-N30 SEP components. SEP wave forms to stimulation on the unaffected side served as the patient's own control. A complete parietal lesion produced contralateral hemianaesthesia without upper motor neuron signs and eliminated the parietal N20-P27-P45 while the prerolandic P22-N30 persisted at usual latencies. The neural generators for the N20 and the P22 components are thus distinct. It is also proposed that direct, short latency pathways convey somatosensory inputs to the motor cortex, independently of connections via parietal areas 2 and 5. Enhancement of P22-N30 after chronic parietal lesions suggests collateral reinnervation by residual inputs after partial deafferentiation of prerolandic cortex. Small postcentral lesions produced astereognosis (with preserved tactile and deep sensation) and reduced or eliminated the N20 and P27 SEP components, but did not affect the P22-N30 components. Precentral lesions with severe hemiplegia (but not prefrontal lesions) eliminated the prerolandic P22-N30 SEP components and did not alter the parietal N20-P27-P45 components. The data are pertinent to the understanding of the pathophysiology of somatosensory deficits and for the diagnostic use of SEPs in cerebral lesions.

Adolescent↗
PubMed1983

[Neurophysiologic study of 2 cases of hemianesthesia as a result of subcortical lesions. Results of recording far-field somatosensory evoked potentials].

The volume-conducted responses of the lemniscal pathways to median nerve stimulation at wrist may be recorded on the scalp (far-field potentials). These positive far-field SEPs components are widely distributed on the scalp and their peaking latencies vary between 9 and 15 milliseconds. In normal adults a maximum of 4 far-field potentials (P9, P11, P13 and P14) may be individualized; two of them (P9 and P14) are constant. These SEPs were studied in two patients with lateralized somatosensory loss; one with a cervico-medullary traumatic lesion, the other with a thalamic infarct. These observations allow the following conclusions 1) the P9 component takes origin in the proximal part of the brachial plexus roots; 2) the P14 potential has a brainstem origin; 3) the contralateral N20 potential is generated in (or close to) the primary somato-sensory cortex (SI). Thus it is possible with a single channel to record the activity of the somatosensory pathways from dorsal roots up the parietal cortex.

Adult↗
PubMed1982

[Aspects of early somatosensory and auditory evoked potentials in neurologic comas and brain death].

Following stimulation of the median nerve at the wrist, SEPs, BAEPs and EEG activity were recorded during the same session in 20 comatose patients (13 head injuries, 6 comas of vascular origin, 1 anoxic coma). Patients were classified according to clinical data. In traumatic comas with clinically preserved brain stem reflexes (5 patients), BAEPs were all present, with preserved cervical N14 and scalp recorded P15 SEPs; the parietal N20 SEP was either present on both sides or unilaterally absent in case of hemispheric, possibly EEG silent, traumatic lesion. In comas with a reactive EEG and absent brain stem reflexes (8 patients), N14 and P15 SEPs were present when the parietal N20 component was absent on both sides. In these patients various aspects of BAEPs were observed, but in most cases (7 out of 8) either the BAEPs were completely absent or only peaks I or I and II were present. In brain-dead patients (7 cases) the cervical N14 was recorded in all cases, the P15 SEP was inconstant and the parietal N20 component was constantly abolished on both sides; in most cases (5 out of 7) all the BAEPs were absent. The practical use of evoked responses for the survey of comatose patients is discussed.

Adolescent↗
PubMed1982

Course of visual evoked potentials in multiple sclerosis: electroclinical correlations and pathophysiological considerations in 25 patients.

Twenty-five MS patients had VEPs recorded at 1-year interval. Abnormal VEPs were observed at least once in 21 patients. They were the only means of assessing the lesional dissemination in nine patients. Their contribution in the diagnostic classification is such that the proportion of "definite" cases rises from 44 to 80% of the 25 cases. The degree of abnormality of the VEPs had no relation to the disability status or to the whole severity of the disease. The main feature was the variability of the VEP latencies at a 1-year interval: they seem to follow the remittent progressive course of the disease whether visual pathways are clinically affected or not. These results are interpreted in light of the pathophysiological data of the disease. In the cases with improvement of normalization of the second VEPs, in plaque edema may be an important mechanism, sometimes free of demyelination so that perfect restitutio ad integrum may occur.

Adult↗