Impaired sensory–motor integration during grasping in writer’s cramp

Odergren, Tomas; Iwasaki, Naoya; Borg, Jörgen; Forssberg, Hans

doi:10.1093/brain/119.2.569

Cited by 98 publications

(59 citation statements)

References 54 publications

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“…In the present study, it was perceived that grip force was increased in patients with writer's cramp compared with normal subjects. The latter confirms the results of Odergren et al 4 for object lifting. In addition, we noticed that grip force during drawer-opening was more strongly modulated in the symptomatic than asymptomatic hand.…”

Section: Grip Force Regulation In Patients Withsupporting

confidence: 91%

“…Even though individuals with writer's cramp demonstrate a movement dysfunction that becomes apparent in a distinctive occupational context, Odergren et al 4 noted that these patients show an impaired capacity in force regulation with their symptomatic hand when lifting objects. In the present study, a drawer-opening task using the precision grip was employed for comparing grip force regulation in the symptomatic versus asymptomatic hand of patients with writer's cramp.…”

Section: Discussionmentioning

confidence: 99%

“…Various neurophysiological changes have been described, ranging from modifications in the excitability of spinal and brainstem pathways to alterations in cortical activity during movement, secondary to abnormalities of basal ganglia function. 2 Deficits in sensorimotor processing are also noticed in dystonia, [3][4][5][6][7][8] indicating that the sensory system might contribute to the pathology. In particular, a disturbed sensorimotor integration has been suggested as a result of initiation of dystonic movements through vibratory stimuli and reduction of these symptoms through anesthesia, 3 improper adaptation of force regulation when lifting objects, 4 inappropriate modulation of electromyographic activity in response to an electrical stimulation, 5 increased activity in primary somatosensory cortex (S1) during writing, 6,7 and decreased activity in S1 during vibratory stimulation at rest.…”

mentioning

confidence: 99%

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Disturbed sensorimotor processing during control of precision grip in patients with writer's cramp

2000

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Section: Grip Force Regulation In Patients Withsupporting

confidence: 91%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Disturbed sensorimotor processing during control of precision grip in patients with writer's cramp

2000

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“…During normal grip, subjects use more force than is necessary to avoid slip, and signals from low threshold mechanoreceptors are used for feedback to increase grip force (Johansson and Westling, 1987). People with writer's cramp use more force than normals (Odergren et al, 1996) and thus have a larger safety margin during lift than normals. Put another way, they have reduced their need for sensory feedback during lifting.…”

Section: Role Of Sensory Representation In Motor Dysfunctionmentioning

confidence: 99%

Sensory representation abnormalities that parallel focal hand dystonia in a primate model

Blake

Byl

Cheung

et al. 2002

Somatosensory & Motor Research

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In our hypothesis of focal dystonia, attended repetitive behaviors generate aberrant sensory representations. Those aberrant representations interfere with motor control. Abnormal motor control strengthens sensory abnormalities. The positive feedback loop reinforces the dystonic condition. Previous studies of primates with focal hand dystonia have demonstrated multi-digit or hairyglabrous responses at single sites in area 3b, receptive fields that average ten times larger than normal, and high receptive field overlap as a function of horizontal distance. In this study, we strengthen and elaborate these findings. One animal was implanted with an array of micro-electrodes that spanned the border between the face and digits. After the animal developed hand dystonia, responses in the initial hand representation increasingly responded to low threshold stimulation of the face in a columnar substitution. The hand-face border that is normally sharp became patchy and smeared over one millimeter of cortex within six weeks. Two more trained animals developed a focal hand dystonia variable in severity across the hand. Receptive field size, presence of multi-digit or hairy-glabrous receptive fields, and columnar overlap covaried with the animal's ability to use specific digits. A fourth animal performed the same behaviors without developing dystonia. Many of its physiological measures were similar to the dystonic animals, but receptive field overlap functions were minimally abnormal, and no sites shared response properties that are normally segregated such as hairy-glabrous combined fields, or multi-digit fields. Thalamic mapping demonstrated proportionate levels of abnormality in thalamic representations as was found in cortical representations.

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“…2,10,22,23,29,33 In this case, the patient demonstrated impairments in fine motor control and stereognosis of the affected lower extremity. Adapted measures from sensorimotor testing in taskspecific dystonia of the upper extremity used to test the lower extremity have not been defined in the literature.…”

Section: Clinical Examination Considerationsmentioning

confidence: 71%