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Biomedical subjects

D Boisson

Publications and source records attributed to D Boisson.

At least 19 recordsLinked to original sources
PubMed2006

Left size distortion (hyperschematia) after right brain damage.

OBJECTIVE: To quantitate a size distortion involving the side of space contralateral to the lesion (contralesional) in two right-brain-damaged patients. METHODS: We studied two right-brain-damaged patients with lesions sparing the occipital lobe and a mild left neglect on target cancellation or line bisection. The lesions involved the temporoparietal region (Patient 1) and the basal ganglia and the insula (Patients 1 and 2). Patients were given drawing tasks and tasks requiring perceptual and visuomotor judgments of horizontal extent. RESULTS: In drawing objects such as a daisy both from memory and by copying, patients exhibited a disproportionate enlargement of the left-hand side of objects and added more left-sided petals to the drawn daisy. This pathologic behavior persisted when the patients were blindfolded and was likely to reflect a perceptual, rather than premotor, size distortion. In a task requiring the perceptual matching of two rectangles, patients underestimated the left-sided stimulus. In a visuomotor task requiring the reproduction of the horizontal extent of a segment, patients exhibited a hyperextension, when a leftward movement was required. CONCLUSIONS: We showed a disordered representation of extrapersonal space, possibly involving a contralesional relaxation of the spatial medium. The deficit does not arise at the level of retinotopic coordinate frames and is independent of unilateral spatial neglect.

Basal Ganglia↗
PubMed2006

Functional anatomy of the therapeutic effects of prism adaptation on left neglect.

OBJECTIVE: To investigate the anatomic substrates underlying the beneficial effect of prism adaptation in five patients with persistent left neglect following right stroke. METHODS: In a functional imaging PET study, we used a covariation analysis to examine linear changes of regional cerebral blood flow over sessions as a function of left neglect improvement. RESULTS: The network of significant brain regions associated with improvement of left neglect performance produced by prism adaptation involved the right cerebellum, the left thalamus, the left temporo-occipital cortex, the left medial temporal cortex, and the right posterior parietal cortex. CONCLUSION: Our results suggest that the realignment of visuomotor coordinates is processed by the cerebellum and that low level sensorimotor adaptation actively modulates cerebral areas, albeit now relying on intact cerebellocerebral connections. Hence, our data support the hypothesis that the beneficial effect of prism adaptation on the clinical presentation of left neglect derives from modulation of cortical regions implicated in spatial cognition.

Adaptation, Physiological↗
PubMed2006

Prism adaptation improves spatial dysgraphia following right brain damage.

Visuo-manual adaptation to prisms produces a long-lasting improvement of visuo-spatial neglect. Improvement is also observed in tasks that do not involve visuo-manual component and that can all be consider to rely on a rightward (ipsilesional) orienting bias. Here, we report positive effects of prism adaptation on spatial dysgraphia, in a neglect patient following right brain damage. A long-lasting improvement concerned the right-page preference reflecting the ipsilesional bias but also the sloping lines and the broken lines reflecting visuo-constructive disorders in handwriting. Moreover, a transient improvement was also evidenced for the graphic errors. These results reinforce the idea that the process of prism adaptation may activate brain functions related to multisensory integration and higher spatial representations and show a generalization at a functional level. Prism adaptation therefore appears as useful tool in the theoretical attempt to identify the underlying 'core' mechanisms of the neglect syndrome.

Adaptation, Physiological↗
PubMed2006

[Handicap and quality of life evaluation in amyotrophic lateral sclerosis].

The impact of amyotrophic lateral sclerosis and consequent disability on everyday life can be assessed with generic or specific and/or functional quality of life scales. Generic scales SF36, SIP (Sickness Impact Profiles) and SIP/ALS 19, SEIQoL have been validated for the assessment of quality of life in SLA. A specific scale has also been worked out and validated in this disease, the ALSAQ-40 scale. The ALSFRS (ALS Functional Rating Scale) is a tool validated to evaluate the patient's functional capacities. However, the patient's quality of life felt does not depend only on the disease course but also the patient's previous psychological profile, the environmental, social conditions and spiritual aspirations. The absence of a cognitive deficit makes the patient particularly lucid about the progressive degradation of health status. Evaluation must be carried out with individually for each patient, taking into account the social and familial environments, to appreciate real living conditions, and the impact of this degenerative disease.

Amyotrophic Lateral Sclerosis↗
PubMed2006

[Physical therapy in amyotrophic lateral sclerosis].

Amyotrophic lateral sclerosis is a neurodegenerative disease, without any curative treatment. Clinical expression is variable and related to loss of motor neurons in the cortex, brain stem and spinal cord. There is little scientific evidence demonstrating the usefulness of physical therapy in this disease. Only stretching exercises, proprioceptive neuromuscular facilitation techniques and functional mobility training seem to have a real benefit in terms of spasticity, quality-of-life and pain. The main objective of physical therapy appears to be the preservation of optimal quality-of-life throughout the course of this incurable degenerative disease.

Amyotrophic Lateral Sclerosis↗
PubMed2006

[What are management practices for speech therapy in amyotrophic lateral sclerosis?].

Amyotrophic lateral sclerosis involves deterioration of speech and swallowing. The objectives of rehabilitation are to maintain a comprehensible speech, using exercises on airflow-phonic coordination and breath, lingual and labial movements. Rehabilitation exercises also focus on the different times of swallowing to improve management of the food bolus in the mouth, to learn facilitating techniques and to adopt postures favoring passage of the food bolus. No studies have addressed the question of the effectiveness of rehabilitation in amyotrophic lateral sclerosis, in term of quality of life, maintenance of comprehensible speech or reduction of respiratory risks. Rehabilitation programs are established on an individual basis according to the clinical presentation and course.

Amyotrophic Lateral Sclerosis↗
PubMed2005

Ipsidirectional impairment of prism adaptation after unilateral lesion of anterior cerebellum.

In a patient with damage of the left cerebellar cortex (SCA territory), the authors tested four combinations of exposure to optical shift (leftward prisms, right hand; rightward prisms, right hand; leftward prisms, left (ataxic) hand; rightward prisms, left (ataxic) hand). He adapted to rightward but not leftward prisms, independent of which hand was used during exposure. This suggests a role of anterior cerebellar cortex in the computation or compensation of ipsidirectional visual error.

Adaptation, Physiological↗
PubMed2005

[Assessment of disability and quality of life in patients with cognitive disorders].

OBJECTIVE: To identify disability, handicap and quality of life questionnaires available for patients with cognitive impairment. MATERIALS AND METHODS: We systematically reviewed the literature in Medline using the keywords assessment, evaluation, deficiency, disability, disadvantage, handicap, quality of life, scale, index, questionnaire, ICIDH-1, and ICIDH-2, combined with the cognitive deficits dysexecutive syndrome, memory deficits, attention deficits, neglect, apraxia, aphasia, agnosia and mood disorders. We focused on validated scales and distinguished scales dedicated to assess disability, handicap and quality of life. RESULTS: At the level of disability, global and specific scales are available. Specific scales exist for dysexecutive syndrome, memory deficits, attention deficits, unilateral neglect, aphasia and mood disorders. French adaptations of foreign language tests and original tests developed in French have been validated in these areas. No specific tool is available for isolated apraxia or agnosia. Generic scales and pathology-specific scales (for stroke, traumatic brain injury, and multiple sclerosis) are available for quality of life. For aphasia, specific tools are available for incapacity handicap and quality of life. CONCLUSION: Previous results show the impact of the ICIDH-1 framework on functional outcome assessment of cognitive impairments. This approach is often limited by the lack of theoretical background and by the difficulty to assess the involvement of environment and anosognosia.

Cognition Disorders↗
PubMed2005

Optic ataxia errors depend on remapped, not viewed, target location.

Optic ataxia is a disorder associated with posterior parietal lobe lesions, in which visually guided reaching errors typically occur for peripheral targets. It has been assumed that these errors are related to a faulty sensorimotor transformation of inputs from the 'ataxic visual field'. However, we show here that the errors observed in the contralesional field in optic ataxia depend on a dynamic gaze-centered internal representation of reach space.

Adult↗
PubMed2005

Visually guided reaching: bilateral posterior parietal lesions cause a switch from fast visuomotor to slow cognitive control.

The visually guided reaching of two patients with bilateral optic ataxia was explored in two experiments. In Experiment 1 simple delayed pointing was compared with immediate pointing. In the immediate pointing task both variable and constant errors increased with target eccentricity. In contrast to the performance of control subjects and contrary to their own beliefs, the patients both showed improved accuracy in the delay condition. This improvement was manifest as a reduction in both pointing variability and in the constant angular error towards the point of fixation. Both angular errors and their improvement with the delay were proportional to target eccentricity. Experiment 2 used a task in which the target was pre-viewed 5s prior to its re-exposure for pointing ('delayed real pointing'). On some trials a conflict was introduced between the present and previous visual information by changing the target's location during the delay. In contrast to control subjects, who ignored the pre-viewed location and aimed directly at the current target, both patients with optic ataxia initiated their movements towards the previously viewed target location. Evidently they relied on off-line information in preference to on-line visual information. In addition, the patients often failed to detect the changes in target location. One of the patients sometimes even guessed incorrectly that the target had changed its location, and her movement trajectory was then more affected by her false belief than by the target's actual location. These findings confirm that posterior parietal lesions severely disrupt direct visuomotor transformations, and suggest that the residual performance is mediated indirectly by expectations or beliefs about target position.

Acoustic Stimulation↗
PubMed2004

[Treatment of focal upper limb spasticity with botulinum toxin after stroke. Interest of an individual approach].

INTRODUCTION: It is now demonstrated that botulinum toxin can improve upper limb spasticity after stroke. OBJECTIVES: This study was designed to assess the efficacy of botulinum toxin on upper limb spasticity with an individual approach. METHODS: Prospective study on 18 patients who had disabling spasticity of upper limb after stroke. For each patient, the treatment's target was fixed preliminary to botulinum toxin injection. Evaluation of efficacy (Ashworth scale and predefined targets) was performed at 1 month and treatment continuation was decided individually. RESULTS: A beneficial effect was reported by most patients when the treatment was aimed at improving comfort or quality of life. In one case, the treatment was designed to improve grasping. In that case, no effect was reported. For three patients, a neurotomy was performed in order to obtain a long lasting effect. For nine patients, repeated injections were decided. For the six other patients, no long-standing treatment was performed. DISCUSSION: This study confirms that botulinum toxin can improve comfort of patients with upper limb spasticity. On the base of our experience, we discussed contribution of botulinum toxin to enhance and optimise strategies for the treatment of focal upper limb spasticity with emphasis on the comparison with selective neurotomy.

Adult↗
PubMed2004

Does action make the link between number and space representation? Visuo-manual adaptation improves number bisection in unilateral neglect.

If the visual world is artificially shifted by only 10 degrees, people initially experience difficulty in directing their actions toward visual goals, but then rapidly compensate the visual distortion. The consequence of such adaptation can be measured as visual and proprioceptive aftereffects, as well as by performance on pointing tasks without visual feedback. Recent work has shown that more cognitive deficits can be improved following prism adaptation in patients with unilateral neglect. Here we show that a short visuo-manual adaptation to prisms improves performance on a mental number-bisection task recently shown to be impaired in unilateral neglect. The association previously found between space and number representation (the mental number line) may thus be grounded in common action principles. Our results suggest that visuo-motor plasticity functionally links parietal areas involved in space and number representation.

Brain Ischemia↗
PubMed2003

Visuo-motor control of the ipsilateral hand: evidence from right brain-damaged patients.

We investigated the extent to which the right hemisphere is involved in the control of the ipsilateral hand by analysing the kinematics of right-hand prehension in right brain-damaged (RBD) patients. We required patients to grasp one of five possible objects, equally-sized and distributed over a 40 degrees wide workspace. With the purpose of investigating the right hemisphere contribution to the on-line visuo-motor control, we also assessed patients' ability to correct their movement "in-flight", in response to a sudden change of object position. Patients' performance was compared to that of aged-matched controls. A Younger group of healthy subjects, matching the population classically tested on double-step paradigms, was also evaluated to fully assess whether patients' kinematics could be partially due to normal ageing. As a further aim, the possible influence of hemispatial neglect was evaluated by comparing the performances of right brain-damaged patients with and without neglect. In normal subjects, the results confirmed and extended the notion of (a). positional tuning of grip formation, and (b). fast reactions following a change in object position. In addition, subtle effects of ageing on visuo-motor behaviour were shown by less efficient movement correction in the Elderly group. Patients executing reach-to-grasp actions into the left contralesional hemispace were selectively affected in both temporal and spatial aspects of movements. While their performances were relatively well preserved in the right hemispace, patients did not show positional tuning of grip formation, nor fast corrections of their movements when acting in the left hemispace. Interestingly, similar deficits were found irrespective of the presence of neglect. These results show that the right hemisphere contributes to the processing of visuo-motor information that is necessary for executing actions with the ipsilateral hand in the contralateral space.

Adult↗
PubMed2003

[Three dimensional gait analysis and controlling spastic foot on stroke patients].

INTRODUCTION: The purpose of this work is to assess the interest of three dimensional gait analysis in measuring the effect of orthesis and of selective tibial neurotomy without visual analysis. METHOD: After clinical examination, gait in the two groups was recorded by a three dimensional motion system (Vicon-Oxford Metrics) with free velocity. The gait of ten stroke patients was compared bare-foot and with ankle-foot orthesis. The gait of nine stroke patients was compared bare-foot before and six month after selective tibial neurotomy. Kinematics data were studied in the sagittal plane, and muscular electrical activity was detected on the affected side by a ten-channel telemetry system using surface electrodes. An analogic visual scale ( EVA) was used by the patient, to assess discomfort during walking. RESULTS: In the "orthesis" group, calf spasticity was 2.5 on the Ashworth scale. With ankle-foot orthesis, the walking discomfort on EVA was significantly reduced from 4.25 to 1.16. Gait speed increased significativelly at 0.42 m s(-1) to 0.59 m s(-1). In swing phase, equinus disappeared. In stance phase equinus and recurvatum were controlled, anterior pelvic tilt decreased and hip extension increased. In the "neurotomy" group, 6 months after the tibial neurotomy, calf spasticity decreased from 3.4 to 0. The walking discomfort on EVA, was significantly reduced from 5.97 to 3.6. Gait speed increased from 0.51 m s(-1) to 0.54 m s(-1). Ankle dorsiflexion on the affected side, was possible during stance for five patients and residual motricity was released during swing phase for two patients. Stance knee recurvatum was corrected in five patients. CONCLUSION: Three dimensional analysis specifies the functional gait disability in stroke patients. It specifies the degree of correction provided by orthesis or tibial neurotomy in the various gait cycle phases and the impact on the superior joints.

Adult↗
PubMed2003

[3D preliminary analysis gait in stroke patients: knee flexion in compensatory strategies].

OBJECTIVE: The aim of this preliminary study was to assess strategies of walking a stride in stroke patients with spastic right hemiplegia. MATERIAL AND METHODS: Gait was recorded in 3D in seven patients without other locomotion disorders. Kinematics data were studied only on the sagittal plane. The position and trajectory markers on the right side were studied during the swing phase in comparison with static standing position. Results were confronted with angular data. RESULTS: Three walking models were defined: 1) near normal gait with normal mobility in the knee; 2) gait with hicking while the flexion of the knee was reduced; 3) gait with a "talus" foot without motor recovery necessitating a pendular movement. DISCUSSION: The second pathological group was characterized with insufficient flexion in the knee in lifting the foot from the floor. In this group, patients adopted a compensation strategy with hicking in making the stride without touching the floor. We raised the question of limiting this adaptive strategy in order to enhance their remaining mobility. CONCLUSION: A 3D strategy gait analysis, before therapeutic choices, seems to confirm the value of analysing kinematic data in stroke patients with hemiplegia. The amplitude of knee mobility and hip compensation strategy can be specifically studied to improve the effectiveness of therapeutic strategies (orthesis, selective tibial neurotomy, botulinum toxin).

Adult↗
PubMed2003

Pointing errors in immediate and delayed conditions in unilateral optic ataxia.

The present paper provides an analysis of the pointing errors of a patient with unilateral optic ataxia (O.K.) following right hemispheric damage, revealing the type of errors related tothe use of the contralesional hand and/or to the reaching of targets located in the contralesional visual field. In addition, comparison between immediate and delayed pantomime pointing allow testing of whether pointing deficits of this patient are specific to real-time visuo-motor control and, subsequently, whether delay could improve his pointing performance. The results show different patterns in the four hand-field combinations. The following conclusion can be drawn from the results of the delayed condition. In the case of patient O. K., the delay reduced the pointing variability for both hands in the left visual field but not in the right visual field. However, the pointing biases did not improve accordingly. As in healthy subjects, target locations tended to be coded in memory with a bias directed toward the fixation point. These results are discussed and contrasted with respect to those previously obtained in the literature in patients with bilateral optic ataxia.

Adult↗