Impairments of Movement Initiation and Execution in Unilateral Neglect - Directional Hypokinesia and Bradykinesia

Mattingley, JB, Bradshaw, JL and Phillips, JG (1992) Impairments of Movement Initiation and Execution in Unilateral Neglect - Directional Hypokinesia and Bradykinesia. Brain, 115 6: 1849-1874. doi:10.1093/brain/115.6.1849


Author Mattingley, JB
Bradshaw, JL
Phillips, JG
Title Impairments of Movement Initiation and Execution in Unilateral Neglect - Directional Hypokinesia and Bradykinesia
Journal name Brain   Check publisher's open access policy
ISSN 0006-8950
Publication date 1992-12-01
Year available 1992
Sub-type Article (original research)
DOI 10.1093/brain/115.6.1849
Open Access Status Not yet assessed
Volume 115
Issue 6
Start page 1849
End page 1874
Total pages 26
Place of publication OXFORD
Publisher OXFORD UNIV PRESS UNITED KINGDOM
Language eng
Abstract Patients with unilateral neglect may exhibit slowness in the initiation of contralesionally directed movements in peripersonal space (directional hypokinesia). The present study used a sequential movement task to characterize any such impairment in a group of 24 patients with right hemisphere lesions, 18 of whom had left neglect. A further five patients with left hemisphere lesions, one of whom had right neglect, were also tested. We measured movement initiation and execution times for leftward and rightward movements in either hemispace and across the body midline. Most left neglect patients, particularly those with lesions involving posterior cortex, showed directional hypokinesia. Left neglect patients with anterior and/or subcortical lesions also showed directional bradykinesia, i.e. a slowing in the execution phase of contralesionally directed movements. This impairment occurred regardless of the spatial location of the apparatus and was exacerbated as patients moved closer to their neglected side. The patient with right neglect showed directional hypokinesia but not directional bradykinesia. Right hemisphere and left hemisphere lesion patients without neglect performed in a manner comparable to controls, who did not exhibit directional hypokinesia or directional bradykinesia. These results suggest that directional hypokinesia is associated with both left hemisphere and right hemisphere damage, but only in the context of unilateral neglect. Moreover, the site of hemispheric lesion may determine the temporal characteristics of movement impairments in neglect. Damage to posterior cortex produces deficits in detecting contralesional targets and initiating movements toward them, while damage to anterior or subcortical structures may disrupt the internal representation of an intended trajectory.
Keyword Primate Motor Cortex
Free Arm Movements
Striatal Dopamine Depletion
Non-Sensory Neglect
3-Dimensional Space
Right-Hemisphere
Visual Neglect
Attention
Lesions
Targets
Q-Index Code C1
Q-Index Status Provisional Code
Institutional Status Unknown

Document type: Journal Article
Sub-type: Article (original research)
Collection: ResearcherID Downloads - Archived
 
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