People with cerebral palsy (CP) are known to rely heavily on visual guidance when making targeted upper-limb movements. In the present study, we examined whether being able to visually monitor the moving limb forms a precondition for people with CP to make accurate upper-limb movements. Eight participants with tetraparetic CP and eight controls were asked to produce large-amplitude, straight-line drawing movements on a digitizing tablet. In half the trials, vision of the moving limb was blocked. Accuracy constraints were manipulated by varying the width of the target and by imposing a maximum width of the movement path. Surprisingly, when vision was blocked movement accuracy was comparable in the two groups. Thus, people with tetraparetic CP do not strictly require constant vision of their moving limb to make accurate upper-limb movements. They compensated for the lack of visual information, however, by prolonging movement time. Using a high pen force proved a general strategic adaptation, possibly to filter out unwanted noise from the motor system or to enhance proprioceptive input.
Dominique van Roon, Bert Steenbergen, and Ruud G.J. Meulenbroek
Nicole Wenderoth, Otmar Bock, and Rainer Krohn
The present study investigates whether the acquisition of a rhythmical bimanual coordination pattern is influenced by existing intrinsic coordination tendencies. Participants were required to learn 1 of 5 new coordination patterns, whose relative phase ϕ was either 36, 60, or 90° away from the 0° and 180° attractors, respectively. They performed 35 trials, each consisting of 2 conditions: In the augmented feedback condition, continuous visual guidance was provided, while in the normal feedback condition participants were required to rely on normal vision of their arms. We found that all to-be-learned patterns were performed with higher accuracy in the visually guided condition, whereas interference with pre-existing coordination tendencies was more pronounced in the normal vision condition. Comparing the learning progress of the 5 groups, we found for patterns close to anti-phase, a smaller improvement and significantly larger phase errors than for patterns close to in-phase. This indicates that the acquisition of a new phase relationship is influenced by existing attractors and that the 180º attractor interfered more strongly with the to-be-learned pattern than the 0º attractor.
Katya Trousset, David Phillips, and Andrew Karduna
with the elbow in full extension. They were also outfitted with a head-mounted display (Z800; eMagine, Bellevue, WA) to provide visual guidance and to eliminate visual cues from the environment (Figure 1 ). Figure 1 —Experimental setup. Subjects were attached with a Velcro strap at the dominant wrist
Lana M. Pfaff and Michael E. Cinelli
– 130 . doi:10.1207/s15326969eco1702_3 10.1207/s15326969eco1702_3 Warren , W.H. , & Whang , S. ( 1987 ). Visual guidance of walking through apertures: Body-scaled information for affordances . Journal of Experimental Psychology: Human Perception and Performance, 13 ( 3 ), 371 – 383 . PubMed doi
Emily E. Gerstle, Kristian O’Connor, Kevin G. Keenan, and Stephen C. Cobb
– 153 . PubMed doi:10.1016/j.clinbiomech.2009.10.008. 10.1016/j.clinbiomech.2009.10.008 19926369 32. Buckley JG , MacLellan MJ , Tucker MW , Scally AJ , Bennett SJ . Visual guidance of landing behaviour when stepping down to a new level
Manuel E. Hernandez, Erin O’Donnell, Gioella Chaparro, Roee Holtzer, Meltem Izzetoglu, Brian M. Sandroff, and Robert W. Motl
1355617711000403 Billington , J. , Field , D.T. , Wilkie , R.M. , & Wann , J.P. ( 2010 ). An fMRI study of parietal cortex involvement in the visual guidance of locomotion . Journal of Experimental Psychology: Human Perception and Performance, 36 , 1495 – 1507 . doi:10.1037/a0018728 Boas , D