Biomedical subjects

J-M André

Publications and source records attributed to J-M André.

8 recordsLinked to original sources

PubMed2006

[Capacity and performance: ambulatory monitoring under controlled and real-life conditions].

OBJECTIVES: To determine the value of ambulatory monitoring in assessing human gait. To describe the sensors, the parameters and the ambulatory devices. MATERIALS AND METHODS: Literature review and practical experience about techniques, principles, objectives and limits. RESULTS: Accelerometry is the main technique for ambulatory monitoring because of its reliability, pertinence of signals and software developed for interpretation. Simultaneous monitoring of heart rate response is clinically relevant. Pedometers and actimeters can answer precise clinical questions about amount of walking activity. CONCLUSION: Ambulatory monitoring during long periods (one day or more) is important, especially for rehabilitation medicine because it measures the actual patient activity performed and participation. The simultaneous monitoring of environmental conditions of activity should improve the interpretation of the data collected.

Humans↗

PubMed2006

Eye movements and visuoverbal descriptions exhibit heterogeneous and dissociated patterns before and after prismatic adaptation in unilateral spatial neglect.

This prospective study examined the effects of prismatic adaptation on visual exploration strategies in patients with left unilateral spatial neglect (USN). Photo-oculographic gaze recordings were obtained, as the subjects (28 brain-damaged; 15 control) performed a free visual exploration task before and after a session of prismatic adaptation. (i) Before prismatic adaptation, the pattern of visual exploration described two subgroups of patients (symmetrical exploration of hemispaces - similar to the control subjects, deficient exploration of left hemispace). Twelve of 20 patients failed to describe significant elements in the left part of the displayed image. Several visuoverbal patterns were observed, some dissociating visual exploration and verbal description. (ii) Immediately after prismatic adaptation, patients with asymmetrical visual exploration presented a significant increase in the number of point fixations and saccades in the left hemispace. Patients with symmetrical exploration presented the opposite pattern. Improved pattern of visual exploration contrasted with an absence of improved verbal description. Eye movements and visuoverbal descriptions exhibit heterogeneous and dissociated patterns before and after prismatic adaptation. This results demonstrate that prismatic adaptation has no effect in certain patients, suggesting that therapeutic indications and evaluation of prismatic test results should take into consideration the heterogeneous nature of USN.

Adaptation, Physiological↗

PubMed2005

[Evaluation of amputees].

INTRODUCTION: Review of the literature about evaluation of amputees. MATERIALS AND METHODS: A search of the Medline and Reedoc databases with the key words lower limb amputee, upper limb amputee, evaluation of lower limb amputee, evaluation of upper limb amputee, survey of lower limb amputee, survey of upper limb and the same words in French for reports on the evaluation of amputees. RESULTS: Evaluations of amputees differ according to the level of amputation (lower or upper limb) and age (adult or child). They concern standing balance, walking (lower limb) and the mono- or bimanual prehensile capacities with or without prostheses in daily living activities and leisure (upper limb) as well as quality of life, personal satisfaction, psychological impact and, in particular, coping strategies. DISCUSSION: For lower-limb amputees, tools to evaluate include scales of deambulation, of which few are valid in French, and global scales (on locomotor capacities, quality of life and satisfaction), which have been recently validated, but only one of them is valid in French. For upper-limb amputees, specific and valid tools are not available for adults; however, for children some functional capacity scales in daily activities have been validated and take into account psychomotor development. None of these tools are valid in French, and their use is scattered and limited to validation studies. CONCLUSION: Only a few tools to evaluate amputees are valid in French for adults, and they concern lower-limb amputees only. Validating some of these tools in French is necessary.

Activities of Daily Living↗

PubMed2004

[Clinical and three-dimensional kinematic features of the upper limb after replantation of the hand].

INTRODUCTION: Functional assessments of hand replantation after traumatic amputation are considered as good although frequent deficits of long fingers mobility and hand sensitiveness occur. AIMS: To evaluate the capability of handling and the compensatory mechanisms involved in handling. METHODS: Prospective study in eight right-handed males who had distal amputation of the left upper limb with hand replantation for more than two years. Eight males with paired age and handedness served as control. Skin sensitiveness (thread test), mobility (TAM), functional capability (Box and Blocks test, 400 points test) and occupational outcome were assessed. Three-dimensional analysis (opto-electronic device) of the motion of the trunk and the upper limbs (arm, forearm, hand) was made during a pointing and gripping-shifting maneuver and the time of the related phases was measured (dynamometric cube device). Correlation between clinical assessments and three-dimensional analysis were tested. RESULTS: Patients with replantation had a remarkable recovery of the absolute and relative times of the various phases of the handling maneuver. Only the gripping phase was significantly prolonged in patients, this result was correlated with the deficit in motor function and sensitiveness of the replanted hand. The visual control was higher because of the lack of superficial and deep sensitiveness. Compensatory mechanisms involved a lateral shift of the replanted limb segments, probably attributed to the lateral shift of the trunk. CONCLUSION: Patient with a replanted hand develops a homogenesis displacement of the trunk and the pectoral girdle to compensate the shortening and the reduction in active mobility of the hand. This compensatory mechanism, observed in a small scale in healthy too, is efficient with respect to the handling phases.

Activities of Daily Living↗

PubMed2004

The effect of tibio-talar arthrodesis on foot kinematics and ground reaction force progression during walking.

Degenerative osteoarthritis in the subtalar and mid-tarsal joints occurring after tibio-talar arthrodesis is thought to be a consequence of abnormal foot dynamics. We hypothesized that the forward tilt of the tibia during stance induces early heel-off and alteration of the progression of ground reaction force (GRF) after ankle arthrodesis. Three-dimensional gait analysis was performed on nine patients who had an ankle arthrodesis fused in a neutral position and on ten control subjects. Patients walking barefoot were compared to controls. The GRF progression was shifted forward during mid-stance, heel-off occurred earlier and was associated with less anterior tilt of the tibia and a more posterior position of the GRF with reference to the metatarsal heads. The GRF progression, heel-off and tibial tilt were not significantly different between patients and controls when walking in shoes but the GRF was still more posterior at heel-off. Increasing the walking speed worsened the anomalies of foot dynamics. These alterations of foot dynamics are thought to be associated with pathogenic stresses applied to the mid-foot.

Analysis of Variance↗

PubMed2004

[Teaching phacosection in a tropical setting].

PURPOSE: The aim of this study was to prospectively evaluate the training of a Malagasy ophthalmologist, already proficient in classic manual extracapsular cataract extraction (ECCE), in a small incision manual technique (phacosection). MATERIALS AND METHODS: Within the activity of the Sight First program to fight blindness in Madagascar, the ophthalmologist of Majunga recruited patients presenting total white cataracts. These patients were operated by phacosection using the local hospital's usual instrumentation along with two specific phacosection instruments and extra single-use material (a precalibrated 3.2 mm knife and viscoelastic products). Peribulbar anesthesia with eye pressure was provided. Postoperative follow-up (visual acuity and corneal status) was conducted on days 1, 7 and 30. RESULTS: Forty-four eyes were operated, the first seven by the instructor assisted by the local ophthalmologist, the next 36 by the local ophthalmologist assisted by the instructor. Five postoperative complications were noted: two cases of posterior capsular rupture (one during implantation) and three cases needing reoperation with aspiration of residual cortical masses. Induced astigmatism was low and visual rehabilitation was good, with all corneas clear at day 30. DISCUSSION: The results are quite acceptable given the training period, with only two marked complications (one not related to the operative technique) and good visual rehabilitation in less than 2 weeks. This small incision technique allowed reduction of induced astigmatism and risk-free management of total white cataracts (independent of operator). CONCLUSION: Small incision manual ECCE by phacosection is a safe, possible management option for difficult cataracts in a tropical setting with only a small increase in cost. Moreover, the training of an ophthalmologist mastering classic manual ECCE appears rapid and risk-free for patients.

Adult↗

PubMed2003

[Disorders of the processing of spatial information in patients with right cerebral lesions and left hemi-neglect].

The aim of this research was to identify, analyze and classify disorders in behavior which occur in the use of mirrors in patients with right cerebral damage presenting left visual spatial hemiplegia. This work was based on models of visual information processing. Seven controls and eleven patients with right cerebral damage performed a test involving grasping of an object using only specular information from a conventional mirror and then from an inverted mirror. The controls grasped up all the cubes straight away. They only experienced minor difficulty with the inverted mirror, mainly in relation to lateral displacement. The patients revealed a variety of behaviors: 1) searching for and trying to seize the object in the conventional and/or inverted mirror, 2) inversion of the paralysed side (left versus right) in the inverted mirror or the appearance of a visual spatial hemiplegia, 3) modifications in the order of grasped (from right to left, from left to right, or at random), 4) directional anomalies in the horizontal plane linked (or not) with disorders in the use of the anteroposterior space. The results of this study confirm that the patients have abnormal behavior in mirror spaces. While the characteristics of this behavior shows analogies with those described in the non-recognition of objects and/or defects in the processing of visual information for localising objects in space, they can be disassociated from them, and constitute separate syndromes. Specific terminology and taxonomy for the clinical forms of mirror agnosia and specular agnosia, of mirror paralysis and specular paralysis, and of specular ataxia are proposed.

Adult↗

PubMed2002

Parametric and resonant transition radiation in periodic stratified structures.

We consider the problem of electromagnetic emission when an electrically charged particle crosses a periodically stratified structure following an arbitrary linear trajectory. A theory generalizing a recently developed method [Phys. Rev. E 63, 016613 (2001)] is presented in the framework of the classical theory of electromagnetism in continuous media. It allows one to account for both the so-called parametric radiation and the resonant transition radiation. We implement our model to interpret the experiments performed by Kaplin et al. [Appl. Phys. Lett. 76, 3647 (2000)] in the x-ray domain with a stack of 300 W/B(4)C bilayers irradiated by 500 MeV electrons.

Journal Article↗