title: Speed-Accuracy Trade-Off in a Trajectory-Constrained Self-Feeding Task: A Quantitative Index of Unsuppressed Motor Noise in Children With Dystonia.
abstract: Motor speed and accuracy are both affected in childhood dystonia. Thus, deriving a speed-accuracy function is an important metric for assessing motor impairments in dystonia. Previous work in dystonia studied the speed-accuracy trade-off during point-to-point tasks. To achieve a more relevant measurement of functional abilities in dystonia, the present study investigates upper-limb kinematics and electromyographic activity of 8 children with dystonia and 8 healthy children during a trajectory-constrained child-relevant task that emulates self-feeding with a spoon and requires continuous monitoring of accuracy. The speed-accuracy trade-off is examined by changing the spoon size to create different accuracy demands. Results demonstrate that the trajectory-constrained speed-accuracy relation is present in both groups, but it is altered in dystonia in terms of increased slope and offset toward longer movement times. Findings are consistent with the hypothesis of increased signal-dependent noise in dystonia, which may partially explain the slow and variable movements observed in dystonia.
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Lunardini
authors.affiliation: Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.
authors.forename: Matteo
authors.initials: M
authors.lastname: Bertucco
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Casellato
authors.affiliation: Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA.
authors.forename: Nasir
authors.initials: N
authors.lastname: Bhanpuri
authors.affiliation: Department of Electronics, Information and Bioengineering, Politecnico di Milano, Milan, Italy.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Pedrocchi
authors.affiliation: Department of Biomedical Engineering, University of Southern California, Los Angeles, CA, USA Department of Child Neurology, University of Southern California, Los Angeles, CA, USA Department of Biokinesiology & Physical Therapy, University of Southern California, Los Angeles, CA, USA Children's Hospital Los Angeles, Los Angeles, CA, USA terry@sangerlab.net.
authors.forename: Terence D
authors.initials: TD
authors.lastname: Sanger
mesh_terms: D061725:Accelerometry; D000293:Adolescent; D001696:Biomechanical Phenomena; D002648:Child; D020821:Dystonic Disorders / Q000503:physiopathology*; D004576:Electromyography; D005247:Feeding Behavior / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D011597:Psychomotor Performance / Q000502:physiology*; D013997:Time Factors; D034941:Upper Extremity / Q000503:physiopathology*; D055815:Young Adult
keywords: childhood dystonia; electromyography; kinematics; signal-dependent noise; speed-accuracy relation