Brown, Liana E

Freezing of gait is a debilitating symptom affecting individuals with Parkinson's disease. Emerging evidence suggests freezing may represent a global motor control deficit beyond gait. We investigated freezing episodes in the upper limbs using spatially-constrained reaching tasks known to elicit freezing of gait. Fourteen people with Parkinson's disease and 13 controls completed reaching tasks under three spatial conditions with varying backgrounds. The tunnel condition produced the greatest kinematic disruptions. Despite people with Parkinson's disease showing significantly longer movement times and slower speeds, they were less accurate in their movements, suggesting observed differences reflect genuine motor control deficits rather than speed-accuracy trade-offs. The tunnel's narrow spatial constraints challenge the motor system's ability to maintain coordinated movement trajectories, with people with Parkinson's disease exhibiting increased trajectory variability. These findings demonstrate that freezing-like episodes extend beyond gait, supporting the hypothesis that freezing represents a global motor phenomenon in Parkinson's disease.

Author Keywords: freezing of gait, motor control, Parkinson's disease, reaching, upper limbs

Freezing is a debilitating phenomenon that reduces quality of life for people withParkinson's disease (PwPD). This study tests the hypothesis that: 1) freezing is linked to executive dysfunction; 2) freezing is a global motor phenomenon, not limited to gait. We compared 14 PwPD to 16 controls. Several aspects of executive function were measured using pro- and anti-saccade tasks under gap and overlap timing conditions, where the gap effect is defined as the reduction in saccade latency associated with the removal of fixation before target presentation. As predicted, results showed larger anti-saccade gap effects in PwPD with than without FOG, and that the pro-saccade gap effect predicted FOG severity in PwPD with FOG. PwPD also demonstrated impaired performance on reaching and walking tasks designed to elicit freezing. These findings strengthen the evidence that executive dysfunction, measured by saccade tasks, is linked to freezing in PwPD.

Author Keywords: executive function, eye movements, freezing of gait, freezing of upper limbs, Parkinson's disease

An athlete's psychological response to a sports-related concussion may influence thesuccess of recovery and return to play. This exploratory study explored how athletes psychologically respond to concussion, using Acceptance and Commitment Therapy to examine the role of psychological flexibility in recovery and return to play. Thirty athletes who experienced a concussion in the past three months completed online surveys measuring symptom severity, sport confidence, psychological strain, anxiety, depression, and psychological flexibility. Depression significantly predicted symptom severity (β = .615, p = .015). Psychological flexibility improved from pre- to post-return to play (p = 0.032, d = 0.45) and was correlated with greater confidence (pre: r = –0.451; post: r = – 0.577) and lower psychological strain (r = 0.471). These findings suggest that increasing psychological flexibility may enhance recovery by reducing distress and building confidence. Return-to-play protocols should include psychological recovery measures.

Author Keywords: Concussion, Injury Recovery, Psychological Flexibility, Return to Play

Pharmacological cognitive enhancement is the use of prescription drugs to improve cognitive functioning in healthy individuals. Multiple ethical concerns have been raised by such use. The purpose of this project was to develop a reliable and valid measure to assess public attitudes about this issue. Participants were university students in Studies 1 (N = 465), 2 (N = 580) and 3 (N = 156). In Study 1 principal components analysis reduced the 90-item Attitudes Toward Pharmacological Cognitive Enhancement Scale to 42 items that loaded onto four components: Cheating/Unfairness, Motivation, Expected Benefits and Safety. Subscale scores differentiated users and nonusers. In Study 2 confirmatory factor analyses supported the model and statistically significant associations were found with related constructs such as attitudes toward performance-enhancing drugs, and prescription drug expectancies. In Study 3 test-retest reliability over a 3-week interval was above .70 for 3 of 4 subscales. Implications and future directions are discussed.

Author Keywords: attitudes, cognitive enhancement, nonmedical use of prescription drugs, scale development, smart drugs

Office workers consistently report greater productivity in the workplace when standing compared to sitting (Chambers et al., 2019; MacEwan et al., 2015; Mantzari et al., 2018). In contrast, laboratory studies report inconsistent evidence that posture (sitting vs. standing) affects cognitive performance, usually operationalized as selective attention (Caron et al., 2020; 2022; Rosenbaum et al., 2017; Smith et al., 2019). The present work assessed whether the discrepancy between workplace and laboratory findings is because workplace tasks are more difficult than the tasks used in laboratory research. Three visual search experiments are reported. Search difficulty was increased in Experiments 1 and 2 and posture difficulty was increased in Experiment 3. There was no evidence that posture affected attention in any of the experiments suggesting that the failure to find an effect of posture on attention in previous work was not due to the task difficulty.

Author Keywords: Cognition, Cognitive Resources, Dual Task, Embodied Cognition, Posture, Selective Attention

Pharmacological cognitive enhancement is the use of prescription drugs to improve cognitive functioning in healthy individuals. Multiple ethical concerns have been raised by such use. The purpose of this project was to develop a reliable and valid measure to assess public attitudes about this issue. Participants were university students in Studies 1 (N = 465), 2 (N = 580) and 3 (N = 156). In Study 1 principal components analysis reduced the 90-item Attitudes Toward Pharmacological Cognitive Enhancement Scale to 42 items that loaded onto four components: Cheating/Unfairness, Motivation, Expected Benefits and Safety. Subscale scores differentiated users and nonusers. In Study 2 confirmatory factor analyses supported the model and statistically significant associations were found with related constructs such as attitudes toward performance-enhancing drugs, and prescription drug expectancies. In Study 3 test-retest reliability over a 3-week interval was above .70 for 3 of 4 subscales. Implications and future directions are discussed.

Author Keywords: attitudes, cognitive enhancement, nonmedical use of prescription drugs, scale development, smart drugs

After active tool-use visual stimuli near a tool are processed more quickly and accurately than those farther away from a tool. Can these near-tool effects be modulated by training demands? To investigate this we asked the participants to complete a tool training task followed by a cross-modal interference task. During the training task the participants performed quick and accurate pointing movements to reach a strict or moderate criterion. The results indicated that the strict group made faster movements than the moderate group. During the cross-modal interference task visual distractors were presented along handheld tools in conjunction with vibrotactile stimuli on the hand. No significant compatibility effects were found for visual distractors near the hand or tool tip, and no consistent group differences were found. Our findings demonstrate the importance of using a novel tool during training, and that virtual stimuli may not be effective to elicit near-tool effects.

Author Keywords: bimodal neurons, cross-modal interference, near-tool effects, tool training, training demands

The assessment of visuomotor function can provide important information about neurological status. Several visuomotor tasks exist for testing in the laboratory, although attempts to make these tests portable to allow quick and reliable assessment have been limited. We developed an assessment tool using two laboratory visuomotor tests as a tablet application: the double-step task, and an interception task. Performance was assessed by measuring the participants' ability to reach toward unpredictably moving targets in each task. Response patterns were compared across equipment types to determine if participants were responding similarly to the moving targets in the standard laboratory and the tablet version of the tasks. On the double-step task, participants adjusted to the displaced target adequately in both the lab and tablet versions. On the interception task, participants intercepted non-accelerating targets, and performed worse on accelerating targets in both versions of the task. These findings suggest that the tablet version of these tasks assesses similar visuomotor processing as the respective laboratory version.

Author Keywords: concussion assessment, double-step task, interception task, visuomotor processing, visuomotor system

The present study examined the role of multiple nights of sleep in the consolidation of a complex motor learning task. Participants were 24 Trent undergraduates, 12 in the learning group (Mage = 20.33, SD = 1.87, 10 female) and 12 in the control group (Mage = 21.92, SD = 3.42, 7 female). Participants underwent 5 consecutive nights of polysomnographic recordings, with a Rock Band learning session on the third night. A series of 2(group)x4(night) ANOVAs were performed on the sleep variables. Interactions were found in the number of spindles detected at Pz, F(333) = 9.19, p <.01, and in the density of spindles detected at Pz, F(3,33) = 4.06, p <.05. The pattern of changes from baseline was significantly different between the two groups; spindles increased in the learning group and decreased in the control group. The novel finding was that spindle number/density remained elevated at the third post-learning night of sleep.

Author Keywords: Motor Learning, Procedural Memory, Sleep, Sleep Spindles

For currently-debated reasons, perception of visual stimuli is enhanced in near-hand space compared to far-hand space. According to the action potentiation hypothesis, near-hand effects result from automatically generated potential motor responses produced upon viewing objects presented in near-hand space. This hypothesis was tested by crossing hand manipulations with two separate techniques designed to elicit action potentiation. The first series of experiments presented participants with a cueing task where images of handled objects served as the cue, and its handle compatibility was manipulated. A consistent near-hand effect was observed, but there was no evidence that the images potentiated action as there was no handle-compatibility effect. The second experiment used a visuomotor competition reaching task, which required participants to initiate reaches toward a distractor display and adjust their trajectory on the fly so as to end the reach at a later indicated target location. For every distractor presented simultaneous and competing motor responses were generated, and differences in how hand presence influenced the resolution of this competition were examined. Based on predictions made, action potentiation is unlikely to be the root cause of the near-hand effect; however, was not possible to rule out this explanation entirely. The findings of these experiments shed light both on the importance and consistency of the near-hand effect, and the difficulties associated with uncovering its nature in human populations.