The effects of assisted cycling therapy (ACT) and voluntary cycling on reaction time and measures of executive function in adolescents with Down syndrome.

BACKGROUND: Reports of positive effects of aerobic exercise on cognitive function in persons with Down syndrome are extremely limited. However, a novel exercise intervention, termed assisted cycling therapy (ACT), has resulted in acutely improved cognitive planning ability and reaction times as well as improved cognitive planning after 8 weeks of ACT in adolescents and young adults with Down syndrome. Here, we report the effects of 8 weeks of ACT on reaction time, set-shifting, inhibition and language fluency in adolescents with Down syndrome. METHODS: Adolescents with Down syndrome (age: ~18 years) were randomly assigned to 8 weeks of ACT (n = 17) or voluntary cycling (VC: n = 16), and a convenience sample (n = 11) was assigned to be an inactive comparison group (NC: n = 11). During ACT, the cycling cadence of the participants was augmented to an average cadence that was 80% faster than the voluntary cadence of the VC group. The increase in cadence was achieved with an electric motor in the stationary bicycle. Reaction time, set-shifting, inhibition and language fluency were assessed before and after 8 weeks of intervention. RESULTS: Power output and heart rates of the ACT and VC groups were almost identical, but the ACT cadence was significantly faster. The ACT group, but not the VC or NC groups, showed significantly improved reactions times (Hedges' g = -0.42) and inhibitory control (g = 0.18). Only the VC group showed improved set-shifting ability (g = 0.57). The ACT and VC groups displayed improved semantic language fluency (g = 0.25, g = 0.22, respectively). DISCUSSIONS: These and previous results support the hypothesis of increased neuroplasticity and prefrontal cortex function following ACT and, to a smaller extent, following VC. Both ACT and VC appear to be associated with cortical benefits, but based on current and previous results, ACT seems to maximize the benefits.

Reversal of handedness effects on bimanual coordination in adults with Down syndrome.

BACKGROUND: Research on unimanual tasks suggested that motor asymmetries between hands may be reduced in people with Down syndrome. Our study examined handedness (as assessed by hand performance) and perceptual-motor integration effects on bimanual coordination. METHODS: Adults with Down syndrome (13 non-right-handed, 22 right-handed), along with comparison groups of adults (16 non-right-handed, 21 right-handed) and children (15 non-right-handed, 22 right-handed) without Down syndrome, drummed with auditory, verbal and visual instructions. RESULTS: In contrast to handedness effects in the children and adults without Down syndrome, right-handed participants with Down syndrome led more with the left hand, and had lower coordination stability than non-right-handed participants with Down syndrome. CONCLUSIONS: The reversed handedness effect during bimanual coordination suggests a complex relationship between handedness and task requirements in adults with Down syndrome.

The use of (symmetry) group theory as a predictive tool for studying bimanual coordination.

Symmetry groups-rules that connect different configurations of a given set of components-represent a compact means of coding for effects, a feature that is desirable in both model- and theory-building. The present study was designed to compare the effects of spatial orientation differences with the various other asymmetries (e.g., timing differences, handedness preferences, the direction of attention) that are accommodated by current models of bimanual coordination. The authors used symmetry groups to predict specific patterns of results. In 2 experiments, participants (N = 13, Experiment 1; N = 9, Experiment 2) coordinated the movements of differently oriented (1 downward and 1 upward) pendulum pairs at a low (0.62 Hz) or high (0.82 Hz) movement frequency to establish an in-phase or antiphase pattern. Consistent with previous results (P. G. Amazeen, E. L. Amazeen, & M. T. Turvey, 1998a), the downward-oriented pendulum tended to lead slightly. In contrast to the effects of other bimanual asymmetries, the downward-oriented pendulum lead was amplified at low frequencies. Although the results contradicted the predictions of existing models of bimanual coordination, they were consistent with predictions from symmetry group theory. In the discussion, the authors focus on the application of symmetry groups to both bimanual coordination and other phenomena with more complex symmetric structures.

Persons with and without Down syndrome use similar strategies when using visual instructions for bimanual drumming.

BACKGROUND: Previous research suggested that persons with Down syndrome (DS) used a different strategy to drum than typical adults. METHODS: The present study examined continuous bimanual drumming strategies in response to different instructions in 10 persons with DS, 10 mental age-matched and 10 chronological age-matched groups. The drumming task required participants to hit two drums with the drumsticks at the same time following verbal (e.g. 'up' and 'down'), visual (e.g. video of both drumsticks moving up and down together) or auditory (e.g. sound of both drums being hit, then cymbal being hit) instructions for 10 s. Sensors placed on the wrists of each participant and the end of each drumstick provided data that allowed the assessment of individual drumming strategies. RESULTS: In general, when persons with DS were following the visual instructions their drumming movements were shorter, straighter and less variable as compared with their movements in the auditory and verbal conditions. CONCLUSIONS: Whether movement paths were straight or curved, the strategy was to move the drumstick and wrist together as one unit.