Premium
Coordination of fingertip forces during precision grip in premanifest Huntington's disease
Author(s) -
Rao Ashwini K.,
Gordon Andrew M.,
Marder Karen S.
Publication year - 2011
Publication title -
movement disorders
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.352
H-Index - 198
eISSN - 1531-8257
pISSN - 0885-3185
DOI - 10.1002/mds.23606
Subject(s) - preload , physical medicine and rehabilitation , grip strength , hand strength , time to peak , medicine , psychology , physical therapy , cardiology , hemodynamics
Abstract Precision grip control is important for accurate object manipulation and requires coordination between horizontal (grip) and vertical (load) fingertip forces. Manifest Huntington's disease (HD) subjects demonstrate excessive and highly variable grip force and delayed coordination between grip and load forces. Because the onset of these impairments is unknown, we examined precision grip control in premanifest HD (pre‐HD) subjects. Fifteen pre‐HD and 15 age‐ and sex‐matched controls performed the precision grip task in a seated position. Subjects grasped and lifted an object instrumented with a force transducer that measured horizontal grip and vertical load forces. Outcomes were preload time, loading time, maximum grip force, mean static grip force, and variability for all measures. We compared outcomes across groups and correlated grip measures with the Unified Huntington's Disease Rating Scale and predicted age of onset. Variability of maximum grip force ( P < .0001) and variability of static grip force ( P < .00001) were higher for pre‐HD subjects. Preload time ( P < .007) and variability of preload time ( P < .006) were higher in pre‐HD subjects. No differences were seen in loading time across groups. Variability of static grip force ( r 2 = 0.23) and variability of preload time ( r 2 = 0.59) increased with predicted onset and were correlated with tests of cognitive function. Our results indicate that pre‐HD patients have poor regulation of the transition between reach and grasp and higher variability in force application and temporal coordination during the precision grip task. Force and temporal variability may be good markers of disease severity because they were correlated with predicted onset of disease. © 2011 Movement Disorder Society