Biomedical subjects

G Rode

Publications and source records attributed to G Rode.

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

High prevalence of nosocomial infections in rehabilitation units accounted for by urinary tract infections in patients with spinal cord injury.

This study (part of the nationwide French prevalence survey of 2001) was organized to investigate the prevalence and risk factors of nosocomial infections (NIs) and the resistant flora in patients hospitalized in rehabilitation units. Two hundred and eighty-six patients were included from two hospitals in the 'Hospices Civils de Lyon' group. Patients were classified into those with and without a spinal cord injury (SCI). Seventy-eight (27.3%) patients had an SCI. They were younger and more often characterized by a low Activity of Daily Life score, bladder incontinence and chronic respiratory disease. Urinary catheterization and mechanical ventilation were more common in these patients. The NI prevalence rate was higher in the SCI group (21.8% vs 4.3%, P<0.00001), particularly for urinary tract infections (UTIs, 19.2% vs 3.4%, P<0.00001). There was a positive relationship between the number of risk factors and NI acquisition. Multi-variate analysis showed that the only independent risk factor for NI acquisition was indwelling urinary catheterization [odds ratio (OR): 11.64, 95% confidence intervals (CI): 2.53-53.65, P=0.002]. Marginally significant factors were chronic kidney or liver disease (OR: 5.84, 95%CI: 0.80-42.68, P=0.082) and SCI (OR: 2.97, 95%CI: 0.61-14.60, P=0.179). The prevalence of antibiotic-resistant micro-organisms was high (nine cases of resistant organisms for 31 infection sites), but there were no differences between the groups. The high rate of NIs, especially UTIs, in SCI patients was not due to an independent effect of SCI but was probably due to the high number of risk factors. These high-risk patients need targeted NI surveillance.

Activities of Daily Living↗

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

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

Right spatial neglect after left hemisphere stroke: qualitative and quantitative study.

OBJECTIVES: Comparatively little research has been conducted on right neglect after left brain damage. The authors sought to assess contralateral neglect in subacute left hemisphere stroke patients using a comprehensive test battery validated in a large control group after right hemisphere stroke. METHODS: Seventy-eight left hemisphere stroke patients were assessed. The test battery included a preliminary assessment of anosognosia and visual extinction, a clinical assessment of gaze orientation and personal neglect, and paper-and-pencil tests of spatial neglect in the peripersonal space. Only nonverbal tests were used. RESULTS: Drawing and cancellation tasks revealed neglect in 10 to 13% of patients. The combined battery was more sensitive than any single test alone. A total of 43.5% of patients showed some degree of neglect on at least one measure. Anatomic analyses showed that neglect was more common and severe when the posterior association cortex was damaged. CONCLUSIONS: The frequency of occurrence of right neglect was, as expected, much lower than that reported in a study using the same assessment battery in right brain damage stroke patients. Nevertheless, neglect was found in a substantial proportion of patients at a subacute stage, suggesting that it should be considered in the rehabilitation planning of left brain damage stroke patients.

Awareness↗

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

[Clinical experience with percutaneus large-core needle biopsies of the breast and evaluation of cytopathological and histopathological results].

OBJECTIVE: Core needle biopsy (CNB) allows a microinvasive diagnosis of breast lesions. We investigated whether imprint cytology of CNB specimens is a useful method of rapidly obtaining additional diagnostic information. MATERIAL AND METHOD: During five years 46 218 breast examinations for 23 300 patients were performed. 563 patients were examined by CNB. The results of imprint cytology were compared with the histopathological results. Statistical analysis was done for all patients who underwent subsequent surgery. RESULTS: 195 of 563 patients were treated surgically. 155 patients exhibited malign lesions. 40 patients showed benign breast lesions. Four patients with malign findings in imprint cytology and histopathology of CNB were treated conservatively. Imprint cytology had a sensitivity of 0.89, specificity of 0.88, positive predictive value of 0.96 and negative predictive value of 0.67. Histopathology revealed a sensitivity of 0.90, specificity of 0.95, positive predictive value of 0.98 and negative predictive value of 0.70. 364 patients with benign findings in imprint cytology and histopathology were controlled subsequently. One of these patients developed five month later an invasive ductal tumor. CONCLUSION: Imprint cytology of CNB is a reliable method to obtain additional diagnostic information. Inadequate and suspicious cases should be evaluated based on complementary diagnostic procedures for breast lesions.

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↗

PubMed2003

[Medical treatment of spasticity].

Spasticity is one of the clinical signs observed after a lesion of the pyramidal tract. Clinical manifestations are polymorphous and depend on the location of the lesion on the pre-motoneuron. Functional consequences are also variable. Only negative effects such as painful spasms, stiffness, distortions, are to be treated. Three different categories of drugs are available: GABA-like (baclofen, benzodiazepine), central alpha 2 agonists (tizanidine, clonidine) and peripheral anti-spastics (dantrolene). Baclofen remains the most commonly used anti-spastic. The preferential indication is spasticity from spinal cord disease, especially when the aetiology is multiple sclerosis. Efficacy of benzodiazepines (diazepam, tetrazepam, clonazepam) is comparable with baclofen; however, side effects (drowsiness) are more frequent. Benzodiazepines are indicated when spasticity is associated with anxiety. Tizanidine is an efficient and well tolerated antispastic. In France, prescription requires a temporary authorization of use. Dantrolen has a peripheral mechanism of action and can be prescribed in the different forms of spasticity. There are other compounds with anti-spastic properties (gabapentine, cyproheptadine, piracetam). Their advantage is rather limited when used alone. Generally, they are administrated in combinaison with usual anti-spastic drugs.

Adrenergic alpha-Agonists↗

PubMed2002

Sensitivity of clinical and behavioural tests of spatial neglect after right hemisphere stroke.

OBJECTIVES: The lack of agreement regarding assessment methods is responsible for the variability in the reported rate of occurrence of spatial neglect after stroke. The aim of this study was to assess the sensitivity of different tests of neglect after right hemisphere stroke. METHODS: Two hundred and six subacute right hemisphere stroke patients were given a test battery including a preliminary assessment of anosognosia and of visual extinction, a clinical assessment of gaze orientation and of personal neglect, and paper and pencil tests of spatial neglect in the peripersonal space. Patients were compared with a previously reported control group. A subgroup of patients (n=69) received a behavioural assessment of neglect in daily life situations. RESULTS: The most sensitive paper and pencil measure was the starting point in the cancellation task. The whole battery was more sensitive than any single test alone. About 85% of patients presented some degree of neglect on at least one measure. An important finding was that behavioural assessment of neglect in daily life was more sensitive than any other single measure of neglect. Behavioural neglect was considered as moderate to severe in 36% of cases. A factorial analysis revealed that paper and pencil tests were related to two underlying factors. Dissociations were found between extrapersonal neglect, personal neglect, anosognosia, and extinction. Anatomical analyses showed that neglect was more common and severe when the posterior association cortex was damaged. CONCLUSIONS: The automatic rightward orientation bias is the most sensitive clinical measure of neglect. Behavioural assessment is more sensitive than any single paper and pencil test. The results also support the assumption that neglect is a heterogeneous disorder.

Activities of Daily Living↗

PubMed2001

Prism adaptation to rightward optical deviation improves postural imbalance in left-hemiparetic patients.

Left-hemiparetic patients show predominant postural imbalance as compared to right-hemiparetic patients. The right hemisphere is crucial for generating internal maps used for perceptual and premotor processing of spatial information. Predominant postural imbalance with right-brain damage could thus result from a distortion of an internal postural map. Well-known manifestations of distorted internal maps due to right-hemisphere lesions, such as hemineglect, may show improvement following prism adaptation shifting the visual field to the right. We therefore investigated the effect of prism adaptation on postural imbalance in left-hemiparetic patients. Three groups of five patients were either adapted to prisms deviating the visual field to the right or left or exposed to neutral prisms while performing reaching movements of the right arm. Postural imbalance was reduced only following prism adaptation to the right. Thus, brief adaptation (i.e., 3 min) to rightward-shifting prisms can dramatically improve postural imbalance. This result shows that the effect of exposure to prisms that horizontally shift the visual field to the right in a reaching task generalizes to the postural system, and it suggests an interaction between horizontal and vertical reference frames. This also supports the theory that predominant postural imbalance in patients with right-brain damage may be partly related to a distortion of an internal postural map.

Adult↗

PubMed2001

Prism adaptation improves representational neglect.

Previous work has shown that various symptoms of unilateral neglect, including the pathological shift of the subjective midline to the right, may be improved by a short adaptation period to a prismatic shift of the visual field to the right. We report here, in two neglect patients the improvement of imagery neglect after prism exposure. Despite a strong neglect observed for mental images, as well as for conventional tests, the mental evocation of left-sided information from an internal image of the map of France was fully recovered following prism adaptation to the right. This improvement could not be explained by the alteration of visuomotor responses induced by the prism adaptation. Therefore, prism adaptation may act not only on sensory-motor levels but also on a higher cognitive level of mental space representation and/or exploration.

Adaptation, Physiological↗

PubMed2001

[Dissociation of retrograde memory impairment in a case of herpetic encephalitis].

OBJECTIVE: To report an uncommon case of memory impairment after meningoencephalitis. METHOD: Detailed description of the history, the lesions, the evolution and review of the bibliography. RESULTS: A 33 year-old man showed a loss of verbal anterograde memory and a dissociation of retrograde memory impairment after an herpetic meningo-encephalitis with lesions predominant in the left temporal lobe. The patient had impairment of verbal anterograde memory. Visual memory, procedural one were intact. He had normal performances in frontal tests. Neuropsychological assessment revealed major loss of episodic biographical memory and public events memory, but sparing of semantic biographical memory and professional knowledge. This patient who was amnesic but who had not difficulties with visual memory, procedural memory, frontal abilities and didactic memory conserved ability to work. CONCLUSION: This case report emphasize the multiplicity of the memory systems and the likely links between episodic biographical memory, semantic biographical memory, autobiographic episodic memory, public event memory and didactic memory.

Adult↗