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Biomedical subjects

B Bussel

Publications and source records attributed to B Bussel.

At least 37 records · Page 2Linked to original sources
PubMed1996

Anticipatory responses to a self-applied load in normal subjects and hemiparetic patients.

A bimanual loading task was studied in eight right-handed normal subjects and nine hemiparetic patients in order to detect anticipatory adjustments and to analyse the reflex and voluntary, responses induced by the perturbation. The left forearm (or the impaired side in patients) was flexed at approximately 90 degrees and free to rotate in a vertical sagittal plane. It was held to resist a load (2-3 kg) dropped either by an experimenter (control situation), or by the subject himself with no visual control (self-applied situation). The load was dropped from the right hand by normal subjects and from the unimpaired hand by hemiparetic patients. The initial distance the load fell was 0.05-0.35 m. The elbow movements of the limb receiving the load were recorded with a linear accelerometer at the wrist, a potentiometer at the elbow and via the EMG signals from flexor muscles. Normal subjects always made an anticipatory flexion movement prior to the impact in the self-applied situation, but not in the control situation. The anticipatory flexion of hemiparetic patients was slower and longer. The amplitude of the anticipatory flexion at the time of impact and its duration were correlated with the mass of the load and the initial distance between the two hands in both groups. The anticipatory flexion reduced the distance through which the load fell and thus its kinetic energy at impact. The impact induced a brisk extension which was always smaller in the self-applied situation for a given kinetic energy. In normal subjects, the amplitude of the monosynaptic reflex (MSR) following the impact in flexor muscles was usually greater in the self-applied situation, but its gain was either reduced or unchanged. The gain of the functional stretch reflex (FSR) was consistently reduced in the self-applied situation. Depression of the FSR gain occurred in only two hemiparetic patients who had the best recovered motor function. Anticipation always ended up minimizing the perturbation following different motor strategies. The normal subjects fell into two groups. One group adjusted the anticipatory forearm flexion to correct the extension disturbance as fast as possible; the second group relied on an accurate adjustment of the final position. Hemiparetic patients showed idiosyncratic intermediate behavior.

Adult↗
PubMed1996

Intrathecal baclofen administration for control of severe spinal spasticity: functional improvement and long-term follow-up.

OBJECTIVES: To assess long-term efficacy and functional benefits of intrathecal baclofen for severe spinal spasticity. DESIGN: A prospective before-after trial. SETTING: A neurological rehabilitation department of a university hospital. Pump implantation was realized in neurosurgery; follow-up was carried out mostly on an outpatient basis. PATIENTS: Eighteen patients with severe and disabling spinal spasticity received intrathecal baclofen by an implantable pump; average follow-up was 37.4 months (range, 9 to 72). MAIN OUTCOME MEASURES: Spasticity (Ashworth and spasms frequency scores); disability (Functional Independence Measure [FIM]). RESULTS: A significant decrease in tone and spasms was observed in all patients. Tolerance appeared during the first 6 to 9 months. Later on, efficacy remained stable, except in cases of mechanical problems of the pump or catheter. Functional assessment found a highly significant (p < .001) increase of FIM score (particularly for bathing, dressing lower body, transfers, and in some cases, locomotion). This was particularly marked in patients with thoracic spinal cord lesion. In cases of severe upper limb dysfunction, FIM was only improved for wheelchair displacements, due to a better sitting position, but nursing became easier and life comfort was enhanced. Severe side effects (overdose) were observed in two cases. CONCLUSION: Efficacy remained stable after 6 to 9 months. Marked improvement of functional independence was observed in paraplegic patients. Improvement was less spectacular in patients with severe upper limb dysfunction, but nevertheless appreciable in terms of life comfort and use of attendants.

Activities of Daily Living↗
PubMed1996

Changes in the execution of a complex manual task after ipsilateral ischemic cerebral hemispheric stroke.

OBJECTIVE: To analyze behavioral adaptation of hemiplegic patients performing a complex manual task without time constraint. It was postulated that ipsilateral motor disturbance could not be observed after a hemispheric stroke. DESIGN: Two manual tasks were used: (1) a new one, "Pig-Tail," required the patients to run a 3-cm-diameter copper ring in a wooden handle along a wavy copper wire without any time constraint; (2) the second task was the Nine-Hole Peg Test (NHPT). SETTING: A hospital department of rehabilitation. PATIENTS: A consecutive sample of 36 patients, who had all suffered an ischemic stroke in the middle cerebral artery territory, 18 with left hemisphere damage (LHD) and 18 with right (RHD), and who had similar ages (mean 54 +/- 13), stroke severity, time since stroke (mean 60 days), and functional independence according to the FIM. MAIN OUTCOME MEASURE: Main data were number of faults, time in seconds, and difference of time for two trials. Analysis compared the results with the same hand for patients and 86 healthy subjects. RESULTS: Patients scores for NHPT were worse than controls, whatever the side of the lesion (p < .05). For Pig-Tail, the number of faults by patients was greater than by controls (p < .05); time was higher for LHD, but not significantly, and was similar to controls for RHD. All patients and controls speeded up between the two trials. Although the RHD were clumsy, they were always faster than LHD patients. CONCLUSION: There are ipsilateral motor disturbances in a complex manual task after hemispheric stoke, even without a speed constraint, and regardless of the hemisphere damaged. Further studies are needed to examine speed control that seemed impaired by right hemisphere damage and could explain clumsiness in these patients.

Adaptation, Physiological↗
PubMed1996

Working memory and supervisory control after severe closed-head injury. A study of dual task performance and random generation.

Survivors of severe closed-head injury (CHI) frequently suffer from slowed information processing. Whether supervisory strategies are additionally impaired remains a point of debate. The first part of this study employed a self-paced dual task; the second part, a random generation task, performed at a paced rate, under single and dual task conditions. A measure of information processing speed was used as a covariate in statistical analysis. In the first experiment, in addition to slow processing, patients performed slightly poorer than controls on each task. In the second experiment, patients' performance (one randomness index in single task condition, and processing of dual task) was impaired even after statistical control of slow processing. These results suggest that there is at least some degree of impairment in supervisory strategies in addition to, but independent of, slowed processing. The clinical significance of this finding is discussed.

Adolescent↗
PubMed1996

Late cognitive and behavioural improvement following treatment of disabling orthopaedic complications of a severe closed head injury.

Interactions of physical, emotional, cognitive and behavioural impairments after severe closed head injury (CHI) remain poorly understood. A 47-year-old man was referred to our department 13 months after a severe CHI. He demonstrated severe left hemiplegia and disabling orthopaedic complications (left hip infectious arthritis, after surgical treatment for heterotopic ossification). His hip was blocked and extremely painful. He was totally dependent for daily-life activities (Functional Independence Measure (FIM) score = 18). Moreover he exhibited severe cognitive and behavioural troubles, which had been stable for many months beforehand, e.g. complete disorientation for time and place, major memory disorders, agitation, anxiety, depression, irritability, disinhibition, aggressiveness and lack of initiative. Pain disappeared within a few weeks after treatment. Progressively, functional improvement occurred (sitting position, transfers, walking between parallel bars). The FIM score increased to 63. Aggressiveness, irritability and agitation disappeared. Surprisingly, neuropsychological assessment demonstrated parallel improvement of cognitive functions, especially in regard to orientation, and to a lesser degree attention and memory. Such an observation should encourage use of active treatment of physical disabilities, even in patients presenting with an apparently poor cognitive prognosis at a late stage of severe CHI.

Cognition Disorders↗
PubMed1996

Evidence for a spinal stepping generator in man. Electrophysiological study.

We present some evidence favouring the presence of a spinal stepping generator in humans. Electrophysiological studies have shown that the spinal cord even deprived of supraspinal influence can generate rhythmic activity, and that some elements of the spinal circuitry on which the generation of stepping rhythmic relies in lower vertebrates exist in man. Moreover, comparison of the variations of the polysynaptic spinal flexor reflex in normal subjects and paraplegic patients brought about some evidence that normal subjects use a spinal locomotor center. Nevertheless, these studies do not absolutely prove the existence of a central pattern generator in man.

Electrophysiology↗
PubMed1995

Fictive motor activities in adult chronic spinal rats transplanted with embryonic brainstem neurons.

The present study was designed to examine the effects of an intraspinal transplantation of embryonic brainstem neurons on fictive motor patterns which can develop in hindlimb nerves of adult chronic spinal rats. Seventeen adult rats were spinalized at T8-9 level and, 8 days later, a suspension of embryonic cells obtained either from the raphe region (RR, n = 8) or from the locus coeruleus (LC, n = 9) was injected caudally (T12-13) to the cord transection. Eight control animals (control rats) were spinalized and injected with vehicle under the same conditions. One to three months later, the animals were decorticated and fictive motor patterns were recorded in representative hindlimb nerves. The data revealed that both control and grafted spinal rats could exhibit two distinctly different fictive motor patterns, one which could be associated with stepping and the other with hindlimb paw shaking. They further showed that following transplantation of embryonic RR or LC neurons the excitability of the spinal stepping generator was increased, whereas that of the spinal neural circuits which generate hindlimb paw shaking was not significantly affected. A histological analysis performed on the spinal cord segments below the transection revealed complete absence of serotonin and noradrenaline immunoreactivity in control spinal animals and, in both types of grafted rats, an extensive monoaminergic reinnervation with synaptic contacts between monoaminergic transplanted neurons and host interneurons and/or motoneurons. The possible mechanisms by which grafted monoaminergic neurons can influence the spinal motor networks are discussed.

Animals↗
PubMed1993

Slowly progressive apraxia: two case studies.

Two patients with a slowly progressive and severe motor apraxia are presented. In one case, there was only apraxia; in the other there was moderate memory disturbance and a mild decline of global intellectual ability, suggesting a more widespread cognitive dysfunction. In this second case, recognition of the correct use of objects was also severely impaired, suggesting a disturbance of motor knowledge. In both cases, apraxia was asymmetrical, and associated with a contralateral atrophy of the upper parietal cortex, suggesting a differential involvement of separate action systems for each hand.

Aged↗
PubMed1993

Trophic effects on testes in paraplegics.

Testicular biopsies and hormone profiles were obtained from 23 paraplegic patients who had sustained a complete spinal cord section. The hormone profiles were normal, but patients with a spinal lesion including the T10-L2 metameres showed a particular pattern of germinal cell abnormalities. The atrophy is multifactorial, but may well include destruction of the sympathetic innervation of the testis by the lesion.

Adolescent↗
PubMed1993

Effect of intrathecal baclofen on the monosynaptic reflex in humans: evidence for a postsynaptic action.

Intrathecal baclofen is a very powerful antispastic agent. Its mechanism of action on the monosynaptic H-reflex in spinal patients was investigated. It could inhibit rapidly and profoundly monosynaptic reflexes in lower limbs, but did not modify Ia vibratory inhibition of the soleus H-reflex. To assess more precisely its effect on Ia afferents, an experimental paradigm using Ia heteronymous facilitation of the soleus H-reflex was used. Intrathecal baclofen did not modify the amount of monosynaptic facilitation of the soleus H-reflex brought about by stimulation of the femoral nerve. This demonstrates that the main part of the inhibitory effect of baclofen on the H-reflex in spinal patients is not due to a presynaptic effect, suggesting a postsynaptic site of action.

Adolescent↗
PubMed1992

Inhibitory effects on flexor reflexes in patients with a complete spinal cord lesion.

The inhibitory effects on flexors of electrical stimulation of a distal peripheral nerve were investigated in 7 paraplegic patients having a complete spinal cord section. The stimuli (3-50 mA) were applied to the sural nerve. Their effects were investigated on: 1) the ipsi- and contralateral H reflex of the Tibialis Anterior (TA); 2) the continuous EMG activity reflexly elicited in TA by a sustained pinch of the foot and 3) on the reflexes evoked in TA by contralateral sural nerve stimulation. Sural nerve stimulation induced two peaks of facilitation of the ipsilateral TA H reflex that could be replaced by inhibition as the stimulus intensity was increased. The comparison of the effect on H reflexes and the EMG activity suggests presynaptic inhibition of Ia fibres at time intervals longer than 300 ms. The stimulation could depress the sustained EMG reflex activity and induce a period of silence whose duration increased with the intensity of the stimulation. As shown in a previous study, a sural nerve stimulation induced a reflex in TA with a prolonged (more than 130 ms) latency. This late reflex could be selectively inhibited by a contralateral sural nerve stimulation, probably at an interneuronal level. These results confirm that the late reflex in TA is similar to the one observed after Flexor Reflex Afferent (FRA) stimulation in the acute spinal cat with DOPA. In addition, they show that at least some part of the "half centre" organization which has been described in the acute spinal cat with DOPA is also present in the human spinal cord chronically deprived of supraspinal control.

Adolescent↗
PubMed1991

Systematic lower limb phlebography in acute spinal cord injury in 147 patients.

This study was concluded on paraplegic and tetraplegic patients of all aetiologies except neoplasic, where paralysis developed within 48 hours. All patients were admitted to the rehabilitation department within 90 days after the onset of paralysis. In a preliminary review of 328 files, there were 27 cases of clinical deep vein thrombosis (DVT) and 10 with pulmonary embolism (PE), 6 of which were fatal. A prospective study was conducted, based on systematic detection of asymptomatic DVT with phlebography. Among the 147 patients, 20 previously presented with DVT. The 127 others underwent phlebography which showed 39 DVT in 29 patients. Eighty seven patients with negative phlebography underwent a second study a month later which showed 14 DVT in 12 patients. Only one minor pulmonary embolism occurred in these 147 patients. The incidence of DVT after acute spinal cord injury and the frequent absence of clinical manifestations were confirmed. Prophylactic anticoagulant therapy is useful but insufficient. This study demonstrates that systematic and repeated detection of DVT by phlebography may reduce the incidence of PE.

Adult↗
PubMed1990

Influence of plantar cutaneous afferents on early compensatory reactions to forward fall.

The influence of cutaneous afferents in the compensatory reactions to a forward fall was investigated. Modification of cutaneous afferent activity was obtained in two different ways: first, by varying the initial pedal support conditions, secondly by anesthetizing the plantar foot sole. The initial pedal support conditions were: 1) bipedal posture, 2) unipedal posture, with contact and 3) unipedal posture, without contact. Nine healthy subjects participated in the control (without anesthesia) experimental session, of which three subjects participated in a session where the plantar sole was anesthetized. The compensatory reactions to a perturbation of balance of a subject initially with a bipedal stance, showed synchronized EMG activity in both Soleus muscles, starting on average at 59 ms, and a burst of EMG activity in the Tibialis Anterior of the starting foot after 200 ms. When the subject was in unipedal posture, the EMG responses on the side which was without support, showed several modifications: the EMG burst in Soleus was strikingly depressed, the response in Tibialis Anterior appeared earlier (mean latency 90 ms) and its magnitude was enhanced. When this foot was in contact with a rigid support, the Soleus showed a short burst of activity and the activity in Tibialis Anterior started at a mean latency of 150 ms.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Effects of flexor reflex afferent stimulation on the soleus H reflex in patients with a complete spinal cord lesion: evidence for presynaptic inhibition of Ia transmission.

The effects of electrically stimulating the Flexor Reflex Afferent (FRA) on the soleus H reflexes were investigated in 34 paraplegic patients having a clinically complete spinal cord lesion. Conditioning stimuli (5-50 mA) were applied to the ipsilateral or contralateral sural nerve. The conditioning-test interval ranged from 20 to 1000 ms. A late ipsilateral flexor reflex (EMG) was found in all patients. A late contralateral extension reflex was sporadically observed in only 3 patients. The excitability curves usually showed two phases of ipsilateral H reflex inhibition and contralateral H reflex facilitation, one between 50 and 130 ms and the other after over 200 ms. These intervals correspond to early and late flexion reflexes. With high intensity stimulation the early and late ipsilateral inhibition fused. An early low threshold ipsilateral facilitation occurred in 9 patients. The contralateral late facilitation was followed by prolonged inhibition in 10 patients. Changes in presynaptic inhibition were assessed by measuring the heteronymous monosynaptic Ia facilitation from quadriceps to soleus. For methodological reasons, it was only possible to investigate the effect of contralateral conditioning volleys which was performed in 5 patients. A significant and regular reduction of the heteronymous Ia facilitation was found in 4 patients. The reduction is taken to indicate that the FRA evokes presynaptic inhibition of Ia transmission to alpha motoneurones. Presynaptic inhibition was also indicated by the enhancement of a vibratory stimulus induced inhibition in 2 subjects. These results are consistent with the hypothesis that the reflex organization in patients with a spinal cord section is similar to that of the acute spinal cat injected with DOPA.

Adolescent↗