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Biomedical subjects

G Lavigne

Publications and source records attributed to G Lavigne.

At least 37 records · Page 2Linked to original sources
PubMed1997

Reliability of scoring EMG orofacial events: polysomnography compared with ambulatory recordings.

The study of sleep bruxism is usually based on clinical history, signs and symptoms. The recording of electromyographic signals with either ambulatory portable home recorders or with polysomnographic techniques in the laboratory environment allows collection of objective data. The present study showed a 100% agreement with clinical evaluation in the recognition of bruxism episodes from the masseter electromyogram recorded with portable recorders and using the polysomnographic technique. On the contrary, scorers had difficulties in discriminating between different types of episodes (phasic, tonic and mixed), the between-scorers agreement varied between 62% and 63% and the kappa-values between 0.43 and 0.33. The ideal time base at which electromyographic signals should be integrated to allow for a good discrimination of bruxism patterns is 0.06 s. The results indicate that portable electromyography recorders are a valuable complement to polysomnographic recordings of orofacial motor activities as they provide a very good recognition rate with adequate time base data collection.

Adult↗
PubMed1996

Persistence of repetitive EEG arousals (K-alpha complexes) in RLS patients treated with L-DOPA.

Compared to normal control subjects, patients with primary restless legs syndrome (RLS) have an increased number of K-complexes, followed by bursts of electroencephalographic (EEG) alpha activity-together these are referred to as K-alpha complexes. In the present study, a large proportion of K-alpha complexes was found to be temporally associated with periodic leg movements in sleep. Because many K-alpha complexes precede the onset of movements, they cannot be considered secondary to the movements themselves. The persistence of K-alpha complexes after suppression of leg movements by means of L-DOPA further supports the hypothesis that these EEG events are a primary phenomenon. The results may have clinical implications because a large proportion of RLS patients complain of non-restorative sleep even after treatment with L-DOPA.

Adult↗
PubMed1994

[The restless leg syndrome: a condition associated with periodic or aperiodic slowing of the EEG].

There are several new developments with regard to semiology, diagnosis, physiopathology and the treatment of restless leg syndrome (RLS). We present here the hypothesis that motor manifestations of the RLS are synchronous to slowing of the cortical activity as measured by the spectral analysis of the EEG. When the subject is resting in bed with his leg outstretched, slowing of the EEG is observed, which could be periodic at the frequency of approximately 1 every 20 seconds or sustained. Leg movements can be periodic at the frequency of approximately 1 every 20 seconds or sustained. Leg movements can be periodic or aperiodic accordingly. On the contrary, periodic leg movements in sleep (PLMS) occur in close temporal relationship with periodic arousal. These results raised the hypothesis that leg movements (RLS and PLMS) may appear at a critical level of cortical activation. This level is reached during sleepiness in the awake subject or during periodic micro-arousal when the subject is asleep. Other results suggest that these periodic changes in the level of cortical activation may also modulate other abnormal motor behavior in sleep such as rhythmic masticatory muscles activity as seen in sleep bruxism. The same mechanism may also be involved in setting the duration of apneic episodes during slow-wave sleep.

Electroencephalography↗
PubMed1994

[Movement disorders during sleep: attempt at classification].

We suggest a classification for abnormal motor behavior during sleep based upon clinical and research studies. Abnormal motor behaviors are classified into four types: aperiodic myoclonic contractions, periodic and stereotype movements, complex and disorganized motor behaviors, complex and organized motor behaviors. Examples for each type are given to support the classification.

Diagnosis, Differential↗
PubMed1991

[Electrical dental anesthesia (EDA), an alternative to local anesthesia?].

Electrical dental anesthesia has recently been suggested as an alternative to local anesthetics for the control of pain related to certain dental acts. This article updates the evidence which supports the efficiency, indications and contra-indications of such a procedure. Although this technique has certain advantages, its use is limited by: 1) how cooperative the patient may be; 2) the time required to explain the procedure to the patient and that which is required to produce the needed clinical effect; and, 3) how efficient it may be relative to the patient in question and the dental treatment rendered.

Anesthesia, Dental↗
PubMed1987

Evidence that periodontal pressoreceptors provide positive feedback to jaw closing muscles during mastication.

1. Mastication was produced by stimulation of the right motor-sensory cortex of urethan-anesthetized rabbits with 15-s trains of shocks (1-ms duration) at 50 Hz. Movements of the lower jaw and jaw muscle electromyograms (EMGs) were recorded on magnetic tape for later computer analysis. 2. The stimulus site was chosen, and stimulus intensity adjusted, so that stereotyped movements were produced that included a wide swing of the mandible to the left side during jaw closure. 3. Control trials were alternated with trials in which a steel ball (2 mm diam) was thrust between the anterior molar teeth on the left side and left in place for several seconds. 4. When the obstruction was first introduced, a jaw opening reflex was sometimes evoked if the ball struck the buccal surface of the advancing mandibular molar teeth. Thereafter, when the ball was crushed between the occlusal surfaces of the teeth, no jaw opening reflex was seen. 5. Instead, the amplitude and duration of all the jaw closing EMGs increased, beginning at least 12 ms after contact with the ball. This caused a prolongation of the slow closing (SC) phase of the cycle that, coupled with a delay in the start of activity in the digastric muscle (jaw opener), prolonged the cycle by more than 60 ms. 6. During the SC phase of the obstructed trials, the medially directed grinding stroke was exaggerated because of an increase in the contraction of the contralateral zygomaticomandibular and anterior temporal muscles. 7. After collecting data, the sensory nerves to the maxillary and mandibular anterior molar teeth were cut to eliminate feedback from the periodontal pressoreceptors. Control and obstructed trials were repeated. 8. Following denervation, the obstructed cycles were of shorter duration. The mandible still moved to the right during SC in some animals, but the increase in closer muscle EMG activity was much reduced. 9. We conclude that periodontal receptors provide positive feedback to the jaw closing muscles during mastication. This is supplemented by input from other receptors, probably muscle spindles. In addition, an increase in periodontal feedback prolongs the SC phase and the early phases of the opening stroke.

Animals↗
PubMed1987

Extended state hospital treatment of severely impaired borderline patients.

Paradigms abstracted from the literature on hospital treatment of severely disturbed patients with borderline personality disorder are not adequate for extended treatment in state hospital settings. A new paradigm, based on Winnicott's concept of the holding environment, incorporates the development of a therapeutic environment in the hospital with the integrated use of mental health and other support services in the community. Treatment can succeed if three primary therapeutic tasks are accomplished, in three phases: the establishment of an adequate holding environment for the patient in the hospital, the maintenance of the hospital holding environment to foster limited structural change, and the transfer of the holding environment from the hospital to the community.

Adolescent↗
PubMed1987

[Comparative study of the effects of verapamil and propranolol therapy in 16 cases of obstructive hypertrophic myocardiopathy].

In a randomized, double-blind, cross-over study with plasma drug assays, 16 patients (11 men, 5 women; mean age 48.56 +/- 3.61 years) presenting with hypertrophic obstructive cardiomyopathy confirmed by echocardiography, left ventriculography and left intraventricular gradient measurement were treated with verapamil 480 mg/day or propranolol 320 mg/day. Both treatments produced functional improvement (p less than 0.01) which was more distinct with verapamil (NS). No changes in cardiothoracic index, echocardiographic parameters and Sokolow's index were observed. Mean total heart work during exercise, which was 1,197.27 +/- 135.89 watts before treatment, increased to 1,260.91 +/- 146.60 watts under propranolol (NS) and to 1,344.09 +/- 171.06 watts under verapamil (NS). Maximum heart rate during exercise, which was 162.3 +/- 3.46 beats/min before treatment, was reduced to a greater extent by propranolol (122.1 +/- 6.6 beats/min; p less than 0.001) than by verapamil (147.7 less than 5.08 beats/min; p +/- 0.01). The two treatments did not significantly modify ventricular arrhythmia, arterial and capillary pulmonary pressures, mean aortic pressure and left ventricular end-systolic pressure. Cardiac index, unchanged under verapamil, fell from 2.98 +/- 0.16 1 X min-1 X m-2 to 2.60 +/- 0.11 1 X min-1 X m-2 under propranolol (p less than 0.05). The left intraventricular gradient present in 5 patients at rest and during exercise, was reduced by both drugs. The gradient under isoprenaline (n = 16), which was 162.07 +/- 18.77 mmHg before treatment, fell to 93.86 +/- 24.48 mmHg with propranolol (p less than 0.05) and to 128.86 +/- 18.22 mmHg with verapamil (p less than 0.05). Left ventricular ejection fraction, mean circumferential fibre shortening speed and compliance coefficient remained unchanged under both drugs (NS). Left ventricular diastolic function, evaluated by radioisotope angiography in the last 9 patients, was most often improved by verapamil (NS). Verapamil was better tolerated generally and by the heart than propranolol. No correlation was observed between plasma verapamil levels and clinical results. Low plasma propranolol levels were often noted in non-responders, suggesting a need for treatment with high doses. It is concluded that at the dosage level used in this study propranolol and verapamil were equally effective, but there were individual variations in best response to one or the other of these two drugs.

Cardiomyopathy, Hypertrophic↗
PubMed1983

Human factors in the measurement of the masseteric silent period.

Human variability in the measurement of the masseteric silent period (SP) was quantified. There were significant differences among (1) observer groups (technicians and dental students), (2) individual observers, (3) repeated measures of the same SP, and (4) trials. No significant observer bias was found. SP's were significantly longer at an inter-incisal distance of 10 mm (48.8 +/- 5.4 ms) than at 14 or 19 mm (44.7 +/- 9.8 ms, 44.5 +/- 6.5 ms).

Adult↗
PubMed1983

Human jaw reflexes.

Although the jaw reflexes are analogous in many ways to the corresponding limb reflexes, important differences do exist. The myotatic reflex appears to contribute more stiffness to the jaw-closing muscles than to limb muscles. The jaw tends to swing up and down during locomotion, and, to maintain a stable position in relationship to the skull, it is necessary that the muscles be made stiff by tonic contraction and/or through a powerful servoreflex. The short conduction pathway and rapid contraction of jaw muscles allow reflex effects to act with little phase lag and to provide efficient compensation. If limb muscle reflexes were equally powerful, their effects could be of more nuisance than help in overcoming expected loads because they occur so late. Perhaps the lack of Renshaw cell inhibition of trigeminal MNs and the potentiation of the jaw jerk reflex by chin vibration are features designed to maintain the strength of the myotatic reflex during locomotion. The jaw-opening reflex (including exteroceptive suppression of jaw-closer muscle activity) is bilaterally symmetrical rather than bilaterally reciprocal, as are the analogous spinal flexor withdrawal reflexes. Bilateral braking is necessary to stop closure, because the mandible crosses the midline, whereas withdrawal of a limb often needs to be compensated for by extension of the other to maintain balance. It has recently been shown in animals that limb and jaw reflex responses are highly context dependent: the size and direction of limb reflexes depend on the phase of locomotion (Forssberg et al., 1977), and the gain of the jaw-opening reflex is increased during the closing phase of mastication (Lund et al., 1981).

Electromyography↗
PubMed1982

[Right coronary artery arising from the pulmonary artery. Surgical treatment].

The authors report the case of an anomalous right coronary artery arising from the pulmonary artery. The patient was an active 18 years old boy who had a continuous murmur with diastolic accentuation, the cause of which was determined at angiography. There were electrical and echocardiographic signs of moderate left ventricular dilatation and thallium scintigraphy showed a myocardial perfusion defect. These were the only detectable consequences of this rare malformation. Normal coronary circulation was reestablished surgically, the indication being the risk of sudden death which has been previously reported rather than acute myocardial ischemia.

Adolescent↗
PubMed1981

[Iatrogenic arteriovenous fistula from the internal mammary artery. Spontaneous closure].

Two cases of arteriovenous fistula arising from the internal mammary artery are described. The detection of the continuous subclavian murmur was preceded by therapeutic procedures in both cases; difficult subclavian vein catheterisation in the first; reoperation of sternotomy for postoperative haemorrhage after open heart mitral commissurotomy in the second. Oxymetry after sampling at, above and below the subclavian vein confirmed the presence of a shunt and allowed estimation of shunt flow, which was minimal in both cases, 11 and 32% of cardiac output respectively. The origin of the fistula at the internal mammary artery and the communicating vein were identified by semi-selective angiography. The latter was superior vena cava in the first case and the internal mammary vein in the second. The low shunt flow probably explains the outcome: spontaneous closure in both cases. This is exceptional in any form of arteriovenous fistula.

Adult↗
PubMed1979

[Treatment of severe chronic cardiac insufficiency with dihydralazine. Short-and median-term results].

17 patients with severe chronic heart failure (class III and IV) were prescribed hydralazine, an arterial vasodilatator, orally at doses of 150 mg to 400 mg/day. Considerable clinical improvement was observed in most patients. After 24 to 48 hours the cardiac index rose 79 p. 100, the systolic index by 67 p. 100 and left ventricular work by 73 p. 100, whilst systemic and pulmonary resistances fell by 51 p. 100 and 34 p. 100 respectively. There was no significant change in systemic blood pressure or in heart rate. These results were confirmed at 4 months. Mean pulmonary capillary pressure varied little at the start of treatment but decreased by 52 p. 100 at medium term (4 and 12 months) in this series. No cases of systemic lupus erythematosis were observed. The main, but not the only, indication of therapy with dihydralazine is low output heart failure with little elevation in the pulmonary capillary pressure, especially in primary cardiomyopathy and valvular regurgitation. At present, treatment should be based on the results of cardiac catheterisation and the dosage adjusted according to the rate of hepatic acetylation.

Administration, Oral↗