Different constraints on grip selection in brain-damaged patients: Object use versus object transport (original) (raw)
Related papers
Experimental Brain Research, 1999
To determine whether the left and right hemispheres play specific roles in goal-directed movements, prehension with the ipsilesional hand was tested in patients with unilateral brain damage. The task required that subjects rotate the hand while reaching for a bar that was presented in different orientations in the frontal plane, thus making high demands on visuospatial processing. The grasped bar had to be put into a hole: under one task condition the placement of the bar was specified, while under another it was not. The constrained task required that the subject anticipate the placing action when planning the initial prehensile movement. Grip selection, reaction times, kinematics of the transport movement, and coordination of hand rotation during transport were assessed in ipsilesional movements of 22 patients with either left or right brain damage (LBD and RBD) and in control subjects. Patients in both groups exhibited performance deficits; however, impairment characteristics differed profoundly between the groups. RBD patients showed prolonged reaction time and degraded kinematics in the unconstrained task, whereas LBD patients performed relatively well when only the orientation of the bar varied, but slowly and frequently incoordinated when the subsequent action was specified. Our findings emphasize the dominant role of the right hemisphere in processing visuospatial aspects of goal-directed movements, whereas the left hemisphere subserves non-spatial aspects of preplanning under increased task demands. Correlations of the patient's performance with results from clinical tests showed that neither deficits in visuospatial perception of RBD patients nor apraxia of LBD patients could account for the observed abnormalities in the use of the ipsilesional hand.
Neuropsychologia, 2014
The scaling of our finger forces according to the properties of manipulated objects is an elementary prerequisite of skilled motor behavior. Lesions of the motor-dominant left brain may impair several aspects of motor planning. For example, limb-apraxia, a tool-use disorder after left brain damage is thought to be caused by deficient recall or integration of tool-use knowledge into an action plan. The aim of the present study was to investigate whether left brain damage affects anticipatory force scaling when lifting everyday objects. We examined 26 stroke patients with unilateral brain damage (16 with left brain damage, ten with right brain damage) and 21 healthy control subjects. Limb apraxia was assessed by testing pantomime of familiar tool-use and imitation of meaningless hand postures. Participants grasped and lifted twelve randomly presented everyday objects. Grip force was measured with help of sensors fixed on thumb, index and middle-finger. The maximum rate of grip force w...
Cognitive Brain Research, 2004
This study was concerned with selection criteria used for grip planning in adolescents with left or right hemiparetic cerebral palsy. In the first experiment, we asked participants to pick up a pencil and place the tip in a pre-defined target region. We varied the size of the target to test the hypothesis that increased end-point precision demands would favour the use of a grip that affords end-state comfort. In the second experiment, we studied grip planning in three task contexts that were chosen to let us test the hypothesis that a more functional task context would likewise promote the end-state comfort effect. When movements were performed with the impaired hand, we found that participants with right hemiparesis (i.e., left brain damage) aimed for postural comfort at the start rather than at the end of the object-manipulation phase in both experiments. By contrast, participants with left hemiparesis (i.e., right brain damage) did not favour a particular selection criterion with the impaired hand in the first experiment, but aimed for postural comfort at the start in the second experiment. When movements were performed with the unimpaired hand, grip selection criteria again differed for right and left hemiparetic participants. Participants with right hemiparesis did not favour a particular selection criterion with the unimpaired hand in the first experiment and only showed the end-state comfort effect in the most functional tasks of the second experiment. By contrast, participants with left hemiparesis showed the end-state comfort effect in all conditions of both experiments. These data suggest that the left hemisphere plays a special role in action planning, as has been recognized before, and that one of the deficits accompanying left brain damage is a deficit in forward movement planning, which has not been recognized before. Our findings have both theoretical and clinical implications. D 2004 Elsevier B.V. All rights reserved.
Different left brain regions are essential for grasping a tool compared with its subsequent use
NeuroImage, 2010
Tool use engages a left hemispheric network including frontal, temporal and parietal regions. Patients with left brain lesions (LBD patients) exhibit deficits when demonstrating use of a single tool (apraxia). When attempting to use a tool, some apraxic patients show errors in the preceding grasping movement. Forty-two LBD patients and 18 healthy controls grasped individual tools and demonstrated their typical use. For patients with a tool use impairment , lesion analysis revealed a large area of overlap in the left hemisphere, mainly in the supramarginal gyrus (SMG). For patients with erroneous grasping (12), the lesion overlay showed overlaps in the left frontal and parietal cortices, especially in the inferior frontal gyrus (IFG) and the angular gyrus (ANG). However, contrasting lesions associated with impaired grasping versus tool use impairments reveal little overlap, limited to the inferior parietal cortex. Presumably the left IFG is involved in selection processes in the context of tool use, such as choosing a functional or non-functional grasping movement depending on the task and the online information about the tool's structure and orientation. The ANG might provide this grasp related information, which is relevant for the specific action. The contribution of the SMG to tool use involves more general principals, such as integrating online and learned tool use information into the action plan for the use movement.
Neuropsychologia, 2015
According to the direct matching hypothesis, perceived movements automatically activate existing motor components through matching of the perceived gesture and its execution. The aim of the present study was to test the direct matching hypothesis by assessing whether visual exploration behavior correlate with deficits in gestural imitation in left hemisphere damaged (LHD) patients. Eighteen LHD patients and twenty healthy control subjects took part in the study. Gesture imitation performance was measured by the test for upper limb apraxia (TULIA). Visual exploration behavior was measured by an infrared eyetracking system. Short videos including forty gestures (20 meaningless and 20 communicative gestures) were presented. Cumulative fixation duration was measured in different regions of interest (ROIs), namely the face, the gesturing hand, the body, and the surrounding environment. Compared to healthy subjects, patients fixated significantly less the ROIs comprising the face and the gesturing hand during the exploration of emblematic and tool-related gestures. Moreover, visual exploration of tool-related gestures significantly correlated with tool-related imitation as measured by TULIA in LHD patients. Patients and controls did not differ in the visual exploration of meaningless gestures, and no significant relationships were found between visual exploration behavior and the imitation of emblematic and meaningless gestures in TULIA. The present study thus suggests that altered visual exploration may lead to disturbed imitation of tool related gestures, however not of emblematic and meaningless gestures. Consequently, our findings partially support the direct matching hypothesis.
Grip Force Coordination in Traumatic Brain Injury -Preliminary Results
Patients suffering from traumatic brain injury (TBI) can have severe disturbances of motor control, especially of dexterity. It is unclear at present if this is just a result of an overall slowing of psycho-motor functions, or if an additional deficit in coordination of the upper extremity has to be considered. We will present preliminary results from a small sample of patients. Our aim was to quantify the force coordination when lifting a small object using the precision grip and compare TBI (n=7) to healthy controls. Forces were recorded by using a 3-D force transducer. Reaction time was significantly increased in TBI but the timing of the various phases of the grip-lift cycle were impaired differentially, compared to controls. The time elapsed from grasping to the onset of lift force (preload phase) was prolonged significantly (mean 197 vs. 62 ms, p<0.01) but the time needed for lifting (load phase) was nearly similar in both groups (mean 150 vs. 111 ms, n. s.). Abnormalities in force scaling during lifting were evident. The peak grip force was slightly increased in TBI (mean 7.9 vs. 5.9 N, n. s.) and this increase of grip force was more prominent in an earlier phase of the lifting action (mean 2.1 vs.0.9 N, p<0.001 at start of loading) compared to controls. The increase of grip force at the start of loading characterizes a sequential execution of grasping and lifting. This contrasts with a preserved regulation of lift force, suggesting a reduced effectiveness of central sensorimotor processing of force coordination in TBI. Distal motor functions of the upper extremity (grasping) were disturbed more distinctly than proximal functions (lifting), as the timing of the former was affected and that of the latter preserved. The effect of rehabilitation on the force coordination will be reported in the follow-up.
Grip force control during object manipulation in cerebral stroke
Clinical Neurophysiology, 2003
To analyze impairments of manipulative grip force control in patients with chronic cerebral stroke and relate deficits to more elementary aspects of force and grip control. Nineteen chronic stroke patients with fine motor deficits after unilateral cerebral lesions were examined when performing 3 manipulative tasks consisting of stationary holding, transport, and vertical cyclic movements of an instrumented object. Technical sensors measured the grip force used to stabilize the object in the hand and the object accelerations, from which the dynamic loads were calculated. Many patients produced exaggerated grip forces with their affected hand in all types of manipulations. The amount of finger displacement in a grip perturbation task emerged as a highly sensitive measure for predicting the force increases. Measures of grip strength and maximum speed of force changes could not account for the impairments with comparable accuracy. In addition to force economy, the precision of the coupling between grip and load forces was impaired. However, no temporal delays were typically observed between the grip and load force profiles during cyclic movements. Impaired sensibility and sensorimotor processing, evident by delayed reactions in the perturbation task, lead to an excessive increase of the safety margin between the actual grip force and the minimum force necessary to prevent object slipping. In addition to grip force scaling, cortical sensorimotor areas are responsible for smoothly and precisely adjusting grip forces to loads according to predictions about movement-induced loads and sensory experiences. However, the basic feedforward mechanism of grip force control by internal models appears to be preserved, and thus may not be a cortical but rather a subcortical or cerebellar function, as has been suggested previously.
Experimental Brain Research, 2012
Movement goals and task mechanics differ substantially between actual tool use and corresponding pantomimes. In addition, apraxia seems to be more severe during pantomime than during actual tool use. Comparisons of these two modes of action execution using quantitative methods of movement analyses are rare. In the present study, repetitive scooping movements with a ladle from a bowl into a plate were recorded and movement kinematics was analyzed. Brain-damaged patients using their ipsilesional hand and healthy control subjects were tested in three conditions: pantomime, demonstration with the tool only, and actual use in the normal context. Analysis of the hand trajectories during the transport component revealed clear differences between the tasks, such as slower actual use and moderate deficits in patients with left brain damage (LBD). LBD patients were particularly impaired in the scooping component: LBD patients with apraxia exhibited reduced hand rotation at the bowl and the plate. The deficit was most obvious during pantomime but actual use was also affected, and reduced hand rotation was consistent across conditions as indicated by strong pair-wise correlations between task conditions. In healthy control subjects, correlations between movement parameters were most evident between the pantomime and demonstration conditions but weak in correlation pairs involving actual use. From these findings and published neuroimaging evidence, we conclude that for a specific tool-use action, common motor schemas are activated but are adjusted and modified according to the actual task constraints and demands. An apraxic LBD individual can show a deficit across all three action conditions, but the severity can differ substantially between conditions.
Neuropsychologia, 1999
To disentangle perceptual\ conceptual and motor aspects of imitation of gestures\ reproduction of meaningless postures of either the hand or the _ngers was examined in two conditions[ In the matching test a target gesture had to be identi_ed among an array of four gestures performed by di}erent persons and seen under di}erent angles of views[ For imitation\ the same gestures had to be imitated[ Thirty _ve patients with LBD\ 10 patients with RBD\ and 06 healthy controls were examined[ LBD patients had more di.culties with imitation than with matching while RBD patients had more di.culties with matching than with imitation[ Regardless of whether imitation or matching was tested\ LBD patients made more errors with hand than with _nger postures whereas RBD patients made more errors with _nger than with hand postures[ This constellation of results is compatible with the assumption that errors are caused by faulty visuoperceptual processing in RBD\ and by defective conceptual mediation in LBD[ Defective motor execution does not appear to be a signi_cant source of imitation errors in either group[ Þ 0888 Elsevier Science Ltd[ All rights reserved[ Keywords] Apraxia^Visuospatial^Right brain damage^Left brain damage^Body schema Corresponding author[ Tel[] ¦38!78!8169 1095^fax] ¦38!78!8169 1978^e!mail] georg[goldenbergÝlrz[tum[de