title: Ipsilesional trajectory control is related to contralesional arm paralysis after left hemisphere damage.
abstract: We have recently shown ipsilateral dynamic deficits in trajectory control are present in left hemisphere damaged (LHD) patients with paresis, as evidenced by impaired modulation of torque amplitude as response amplitude increases. The purpose of the current study is to determine if these ipsilateral deficits are more common with contralateral hemiparesis and greater damage to the motor system, as evidenced by structural imaging. Three groups of right-handed subjects (healthy controls, LHD stroke patients with and without upper extremity paresis) performed single-joint elbow movements of varying amplitudes with their left arm in the left hemispace. Only the paretic group demonstrated dynamic deficits characterized by decreased modulation of peak torque (reflected by peak acceleration changes) as response amplitude increased. These results could not be attributed to lesion volume or peak velocity as neither variable differed across the groups. However, the paretic group had damage to a larger number of areas within the motor system than the non-paretic group suggesting that such damage increases the probability of ipsilesional deficits in dynamic control for modulating torque amplitude after left hemisphere damage.
authors.affiliation: Research Service (151), New Mexico Veterans Affairs Healthcare System, Albuquerque, NM 87108, USA. khaaland@unm.edu
authors.forename: Kathleen Y
authors.initials: KY
authors.lastname: Haaland
authors.forename: Sydney Y
authors.initials: SY
authors.lastname: Schaefer
authors.forename: Robert T
authors.initials: RT
authors.lastname: Knight
authors.forename: John
authors.initials: J
authors.lastname: Adair
authors.forename: Alvaro
authors.initials: A
authors.lastname: Magalhaes
authors.forename: Joseph
authors.initials: J
authors.lastname: Sadek
authors.forename: Robert L
authors.initials: RL
authors.lastname: Sainburg
mesh_terms: D000704:Analysis of Variance; D001132:Arm; D001696:Biomechanical Phenomena; D001921:Brain / Q000473:pathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D010243:Paralysis / Q000209:etiology* / Q000473:pathology; D020521:Stroke / Q000150:complications* / Q000473:pathology; D013647:Task Performance and Analysis