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Biomedical subjects

R Guieu

Publications and source records attributed to R Guieu.

50 records · Page 3Linked to original sources
PubMed1992

Nociceptive threshold in patients with epilepsy.

Clinical practitioners have often observed in the course of their daily work that the pain thresholds of epileptic patients seem to differ from those of healthy subjects. These patients can suffer from quite severe traumatic lesions without apparently experiencing any pain. Since they are usually under treatment for epilepsy, it is difficult to determine whether the absence of pain is due to these patients' epileptic condition or to its treatment, since most antiepileptic drugs also have analgesic effects. In the present study, it was proposed to assess the pain thresholds of 15 epileptic patients (10 with tonic-clonic seizures generalized at outset and 5 with temporal lobe epilepsy), by measuring the leg flexion nociceptive reflex (or RIII reflex) threshold: the stimulation threshold at which this reflex is triggered is known to be correlated with the pain threshold. The nociceptive threshold of the patients with generalized epilepsy was not found to differ from that of the control population, whereas that of the patients with temporal lobe epilepsy was spontaneously high and was not reversed upon injecting naloxone. These data are discussed from the point of view of the pain pathways and mechanisms possibly involved.

Adolescent↗
PubMed1992

Identifying the afferents involved in movement-induced pain alleviation in man.

It has been clearly established that the perception of nociceptive stimulus decreases in intensity when movement is initiated in the part of the body to which the stimulus is applied. The pain alleviation is probably at least partly due to the activation of afferents which occurs during the movement. The present experiments were carried out with a view to investigating which groups of afferent fibres is mainly responsible for the gating of the nociceptive messages which occurs during movements. In eight volunteers we investigated the changes in the amplitude of the nociceptive leg flexion reflex (RIII) when the subjects were at rest, when they were performing active or passive ankle movements and when the spindle proprioceptive pathway was mobilized by applying vibratory stimulation to the Achilles tendon. Similar experiments were also carried out with eight other volunteers after anaesthetizing the ankle skin mechanoreceptors. This method was chosen because a clear-cut correlation is known to exist between the amplitude of the nociceptive motor reflex and the intensity of the pain perceived by the subject. The data obtained clearly show that anaesthesia of cutaneous mechanoreceptors connected to the large diameter afferent fibres prevented the decrease in the motor response which otherwise accompanied both active and passive movements. Activation of the Ia fibre group by tendon vibration resulted on the contrary in an increase in the amplitude of the motor response. Movement-induced pain alleviation therefore does not mainly involve the activation of the Ia group of fibres.

Adult↗
PubMed1992

Analgesic effect of indomethacin shown using the nociceptive flexion reflex in humans.

This study investigated whether indomethacin has an analgesic effect on the central nervous system. As analgesics which affect the central nervous system produce a correlated decrease in the subjective sensation of pain and in the nociceptive reflex in humans, the amplitude of the nociceptive flexion of the biceps femoris was studied. Eight patients (six men, two women) aged 35-70 years (mean 51) with rheumatic diseases were included in the study. Each patient was his or her own control and was given a single intramuscular injection of either 50 mg of indomethacin or a placebo. A placebo controlled, double blind experimental design was used. Patients were evaluated before and 30, 60, and 75 minutes after the injection. Seventy five minutes after injection, indomethacin gave a 54% decrease in the amplitude of the nociceptive reflex, whereas the placebo produced a decrease of only 12%. This suggests that indomethacin exerts a depressive effect on the amplitude of the nociceptive reflex and affects the central nervous system as part of its analgesic action.

Adult↗
PubMed1992

[Nociceptive threshold and Parkinson disease].

It has now become possible to measure pain thresholds in man by the threshold or amplitude of the leg flexion nociceptive reflex (RIII reflex). These parameters accurately reflect the pain levels perceived by the patients. The aim of the present study was to assess pain thresholds in Parkinsonian patients, using the RIII reflex. Painful phenomena are often mentioned in Parkinson disease, but the perceived pain threshold level can be difficult to assess because of the depressive symptoms which are often associated with Parkinson disease. In 8 cases out of 10, the pain threshold was found to be higher in patients with Parkinson disease than in a control population of the same age: in 2 cases, naloxone injection led to recovery of the normal pain threshold level.

Aged↗
PubMed1992

Nociceptive threshold and physical activity.

Previous studies using subjective tools to measure pain have shown that muscle exercise can have analgesic effects in man. The nociceptive leg flexion reflex (or RIII reflex) is a useful objective tool for assessing human pain. In this study, the pain threshold was assessed using the nociceptive flexion reflex in six high-level athletes 1) at rest in comparison with 8 control subjects and 2) after exercise requiring the production of a 200-Watt force over a period of 20 minutes. The nociceptive flexion reflex threshold at rest was found to be spontaneously higher in the athletes than in the controls. Physical activity resulted in a significant increase (+53%) in the threshold of the nociceptive reflex in the athletes. The role of stress-induced analgesia, the reduction in perceived intensity of stimuli during movement, and the release of opioids are discussed.

Adult↗
PubMed1992

[Typical and atypical forms of neuralgic amyotrophy of the shoulder: 86 cases].

Eighty-six cases of neuralgic shoulder amyotrophy are reported. Among these, 67 cases were concordant with the usual semeiological description. The other cases were atypical in their anatomical distribution (extensive or restricted to peripheral nerve rami), in their course (chronic or recurrent or alternating from one side to the other) and in their cause, notably familial forms. The continuum existing between these variants is most probably due to an immuno-allergic mechanism.

Adolescent↗
PubMed1991

Analgesic effects of vibration and transcutaneous electrical nerve stimulation applied separately and simultaneously to patients with chronic pain.

The analgesic effects of transcutaneous electrical nerve stimulation (TENS) and vibratory stimulation (VS), used both separately and simultaneously, were compared in 24 patients suffering from chronic pain. We tested the hypothesis that these combined procedures might improve the pain reducing effects obtained with a single type of stimulation, since they make it possible to recruit a larger number of large diameter afferents and/or to increase the discharge frequencies. Four 35-minute treatment sessions (VS, TENS, VS + TENS, Sham stimulation) were run with each patient. The vibrations (100 Hz) and TENS (100 Hz) were applied to the surface of the painful region. The sham stimulation treatment consisted of positioning the TENS electrodes without actually delivering any current. The short form of the McGill pain questionnaire was used to assess the subjects' pain levels. The assessments took place immediately after any treatment (0h.), and again 4 hours and 24 hours later. The results showed that dual stimulation not only alleviated pain in more cases than either VS or TENS alone, but also had stronger and more long-lasting analgesic effects. On the other hand, all three types of stimulation used produced stronger analgesic effects than those obtained with the sham stimulation.

Adult↗
PubMed1990

Pain relief achieved by transcutaneous electrical nerve stimulation and/or vibratory stimulation in a case of painful legs and moving toes.

A patient is described with painful legs and moving toes. The pain had been occurring for more than 15 years, and a variety of therapies had been attempted with only partial, if any, success. Only morphine had succeeded in relieving the pain, but it had to be discontinued to avoid tolerance and dependence. We devised a treatment consisting of transcutaneous electrical nerve stimulation (TENS), vibratory stimulation (VS), and a combination of the two methods (TENS + VS). TENS brought about partial pain relief, but was less effective than VS; dual stimulation (TENS + VS) led to complete alleviation of the pain. Four months later, the patient was applying dual stimulation himself at home and was thus able to maintain complete relief with 3 or 4 weekly sessions. We suggest that dual stimulation results in a large-scale recruitment of large-diameter afferent fibres and may thus set up a powerful inhibitory control of nociception in our patient.

Adult↗
PubMed1990

[Tendon vibrations as a tool for clinical investigation of the myotatic loop].

The degree of alteration of the myotatic loop was evaluated in 6 patients with polyradiculoneuropathy by studying deep reflexes and vibratory motor responses. The results showed that the reflex motor responses induced by vibration reappeared 2 to 4 weeks before the deep reflexes. Vibrations, therefore, could be a useful tool for the clinical follow-up of polyradiculoneuropathy.

Adult↗
PubMed1990

[Congenital blepharoptosis. Diagnosis and treatment].

The congenital blepharoptosis is the most frequent palpebral abnormality. The anatomical, physiological and clinical aspects of the congenital blepharoptosis are successively discussed. Clinical and anatomopathological studies support the hypothesis of a myogenic basis for congenital genuine blepharoptosis and the hypothesis of a neurogenic basis for the ptosis with synkinetic phenomena. The different surgical methods are then described and their results compared.

Blepharoptosis↗
PubMedDate not supplied

[Methodology of clinical studies of myorelaxants].

Myorelaxants, a specific pharmacologic group, are often prescribed. However, for many molecules, therapeutic trial methodology is not adapted. A review of the fundamental aspects of pharmacological trial clearly show a need for diagnosis and inclusion criteria, definition and validation for methods of assessment, analysis of the dose-response curve on term of effectiveness according to the pharmacologic and clinically established rules. Rational prescription of myorelaxants will arise from this principles.

Clinical Trials as Topic↗