Neurological problems affecting hand dexterity.

Full Abstract

The first objective of this review is to summarize how grip force and load force (holding and transporting forces) are coordinated. Usually, the two forces vary in parallel, thereby resulting in a constant force ratio. Departures from this rule have been observed, however, depending on dynamic task constraints. The second objective is to summarize some of the pathophysiology of grasping in movement disorders. By means of a drawer-pulling task, regulation of grip force was analyzed when pulling was perturbed either by self-induced or externally applied load disturbances. Normal subjects automatically increased grip force in anticipation to the expected load. In the same situation, hemiparetic patients failed to generate proactive grip force and frequent slips were observed. Cerebellar patients were shown to adopt a 'default' strategy in producing high grip force output when the drawer had to be pulled up to its mechanical stop. This differed from the more flexible normal mode of raising grip force in accord with the pulling speed. In patients with Huntington's Chorea, grip/load force coordination differed from that of normal subjects, as expressed in an overscaled grip force. This might be a secondary, less flexible 'default' strategy to overcome the failure in adapting grip force to upcoming disturbances. Writer's cramp patients overscaled grip force in both the dominant and non-dominant hand, and grip force further increased when hand muscles were vibrated, suggesting an abnormal sensorimotor integration. The results illustrate the degrading consequences of cortical and subcortical pathology on manual dexterity, which is sometimes partly compensated for by new, less flexible default strategies.

Author information

Author/s: Wiesendanger, M (M); Serrien, D J (DJ);

Affiliation: Laboratory of Motor Systems, Department of Neurology, University of Berne, Inselspital, BHH-M130, CH-3010, Berne, Switzerland. mario.wiesendanger(-atsign-)insel.ch

Journal and publication information

Publication Type: Journal Article; Research Support, Non-U.S. Gov't; Review

Journal: Brain research. Brain research reviews (Brain Res Brain Res Rev), published in Netherlands. (Language: eng)

Reference: 2001-Oct; vol 36 (issue 2-3) : pp 161-8

Dates: Created 2001/11/05; Completed 2002/02/08; Revised 2007/02/26;

PMID: 11690612, status: MEDLINE (last retrieved date: 2/18/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

External Links for this article
(including full text providers, if available):

Click Electronic Full-text Provider Links to see options for finding the electronic full text links to this article. Note there may be a subscription or fee required for access to the full text. See our FAQ for information on finding FREE full text articles.

This article may also be located in paper journal collections available in many libraries. Use the Journal and Publication Information above to find the full article.