title: Rhythmic arm movements are less affected than discrete ones after a stroke.
abstract: Recent reports indicate that rhythmic and discrete upper-limb movements are two different motor primitives which recruit, at least partially, distinct neural circuitries. In particular, rhythmic movements recruit a smaller cortical network than discrete movements. The goal of this paper is to compare the levels of disability in performing rhythmic and discrete movements after a stroke. More precisely, we tested the hypothesis that rhythmic movements should be less affected than discrete ones, because they recruit neural circuitries that are less likely to be damaged by the stroke. Eleven stroke patients and eleven age-matched control subjects performed discrete and rhythmic movements using an end-effector robot (REAplan). The rhythmic movement condition was performed with and without visual targets to further decrease cortical recruitment. Movement kinematics was analyzed through specific metrics, capturing the degree of smoothness and harmonicity. We reported three main observations: (1) the movement smoothness of the paretic arm was more severely degraded for discrete movements than rhythmic movements; (2) most of the patients performed rhythmic movements with a lower harmonicity than controls; and (3) visually guided rhythmic movements were more altered than non-visually guided rhythmic movements. These results suggest a hierarchy in the levels of impairment: Discrete movements are more affected than rhythmic ones, which are more affected if they are visually guided. These results are a new illustration that discrete and rhythmic movements are two fundamental primitives in upper-limb movements. Moreover, this hierarchy of impairment opens new post-stroke rehabilitation perspectives.
authors.affiliation: Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place du Levant 2, 1348, Louvain-la-Neuve, Belgium.|Louvain Bionics, Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.
authors.forename: Patricia
authors.initials: P
authors.lastname: Leconte
authors.affiliation: Institute of Neuroscience, Université catholique de Louvain, Tour Pasteur - Avenue Mounier 53, 1200, Brussels, Belgium.|Institute of Information and Communication Technologies, Electronics and Applied Mathematics, Université catholique de Louvain, Avenue Georges Lemaître 4, 1348, Louvain-la-Neuve, Belgium.|Department of Kinesiology, Movement Control and Neuroplasticity Research Group, KU Leuven, 3001, Heverlee, Belgium.
authors.forename: Jean-Jacques
authors.initials: JJ
authors.lastname: Orban de Xivry
authors.affiliation: Institute of Experimental and Clinical Research, Université catholique de Louvain, Tour Pasteur - Avenue Mounier 53, 1200, Brussels, Belgium.|Physical Medicine and Rehabilitation Department, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, 1200, Belgium.|Louvain Bionics, Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Stoquart
authors.affiliation: Institute of Experimental and Clinical Research, Université catholique de Louvain, Tour Pasteur - Avenue Mounier 53, 1200, Brussels, Belgium.|Physical Medicine and Rehabilitation Department, Cliniques universitaires Saint-Luc, Université catholique de Louvain, Brussels, 1200, Belgium.|Louvain Bionics, Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.
authors.forename: Thierry
authors.initials: T
authors.lastname: Lejeune
authors.affiliation: Institute of Mechanics, Materials and Civil Engineering, Université catholique de Louvain, Place du Levant 2, 1348, Louvain-la-Neuve, Belgium. renaud.ronsse@uclouvain.be.|Institute of Neuroscience, Université catholique de Louvain, Tour Pasteur - Avenue Mounier 53, 1200, Brussels, Belgium. renaud.ronsse@uclouvain.be.|Louvain Bionics, Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium. renaud.ronsse@uclouvain.be.
authors.forename: Renaud
authors.initials: R
authors.lastname: Ronsse
mesh_terms: D000328:Adult; D001132:Arm / Q000503:physiopathology*; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology / Q000503:physiopathology*; D020521:Stroke / Q000150:complications / Q000503:physiopathology*
keywords: Discrete movements; Rehabilitation; Rhythmic movements; Stroke; Upper limb