Assessing the impact of task difficulty and external cues on movement kinematics in older adults
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1
Monash University, School of Psychology and Psychiatry, Australia
Background: Sensorimotor control tends to deteriorate with age due to a variety of structural and biochemical changes in the central nervous system. In order to lessen the motor impairments associated with ageing, a better understanding of the structure of goal-directed movement is needed. Additionally, little attention has been given to the role of external cues in goal-directed movement in healthy older adults. This study sought to compare movement kinematics between older and younger adults while manipulating both task difficulty and availability of external cues.
Methods: Twenty-five older adults and twenty-five younger adults completed a reciprocal aiming task incorporating Fitts’ law. The task comprised 2 targets presented on a touchscreen computer, requiring participants to make reciprocal movements between the targets as quickly and accurately as possible. Ten movements were initially completed in the presence of two target circles (externally cued), followed immediately by the completion of a further 10 movements in the absence of the visual targets (internally cued). This enabled the quantification of movement time, movement planning and error processing, via the manipulation of task difficulty according to target size and distance.
Results: No group differences were observed in movement time or deceleration time, nor were there differences in the symmetry of the movement profile, as depicted by the proportion of time spent accelerating compared to decelerating. Older adults spent more time dwelling on targets between successive movements, than younger participants, with this effect intensified in the presence of external cues. In the absence of external cues, older adults produced greater errors and displayed more variability in movement endpoints than younger adults, with this effect exacerbated when targets were close together.
Discussion: Results suggest that older adults display a greater dependency on visual information in order to accurately plan their movements than younger adults. Furthermore, accuracy is more severely impacted in older adults in the absence of visual cues, compared with younger adults.
Keywords:
Fitts’ law,
Sensorimotor control,
Aged,
movement time,
Visual Processing
Conference:
ACNS-2013 Australasian Cognitive Neuroscience Society Conference, Clayton, Melbourne, Australia, 28 Nov - 1 Dec, 2013.
Presentation Type:
Poster
Topic:
Motor
Citation:
Dimech-Betancourt
B,
Despard
JL,
Ternes
A,
Poudel
G and
Georgiou-Karistianis
N
(2013). Assessing the impact of task difficulty and external cues on movement kinematics in older adults.
Conference Abstract:
ACNS-2013 Australasian Cognitive Neuroscience Society Conference.
doi: 10.3389/conf.fnhum.2013.212.00010
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Received:
15 Oct 2013;
Published Online:
25 Nov 2013.
*
Correspondence:
Ms. Bleydy Dimech-Betancourt, Monash University, School of Psychology and Psychiatry, Clayton, Australia, bdim1@student.monash.edu