Paul van Donkelaar

Bio: Paul van Donkelaar is an academic researcher from University of British Columbia. The author has contributed to research in topics: Concussion & Poison control. The author has an hindex of 37, co-authored 101 publications receiving 4294 citations. Previous affiliations of Paul van Donkelaar include University of Oregon & University of Calgary.

Gait stability following concussion.

Abstract: Introduction: The need to identify functional impairment following a brain injury is critical to prevent reinjury during the period of recovery. However, little is known about the effect of concussion on dynamic motor function. Purpose: The purpose of this study was to examine the effect of concussion on a dynamic motor task under conditions of divided and undivided attention over the course of 28 d. Methods: Fifteen subjects with concussions (CONC) and 15 uninjured controls (NORM) were observed while walking with undivided attention and while concurrently completing simple mental tasks. The CONC were assessed within 48 h of injury and again at 5, 14, and 28 d postinjury. The NORM were evaluated at the same time intervals. Whole-body motion data were collected to examine displacement and velocity of the center of mass (COM) and the maximum separation between the COM and center of pressure (COP). Three-way repeated-measures mixed-design ANOVA and Tukey post hoc tests were completed to determine differences between group, task, and testing day (P < 0.05). Results: Several aspects of gait stability were compromised in the CONC group for up to 4 wk after injury. CONC were found to walk significantly slower during dual tasks on all testing days when compared with the uninjured controls. The injured subjects were also found to have greater sway and sway velocity than controls when attention was divided for up to 28 d postinjury. Conclusion: The findings of this study suggest that concussion may have long-term observable and measurable effects on the control of gait stability.

Cognitive task effects on gait stability following concussion

Abstract: The purpose of this study was to determine how two different types of concurrent tasks affect gait stability in patients with concussion and how balance is maintained. Fourteen individuals suffering from a grade II concussion and 14 matched controls performed a single task of level walking and two types of concurrent tasks during level walking: a discrete reaction time task and a continuous sequential question and answer task. Common gait spatial/temporal measurements, whole-body center of mass motion, and the center of pressure trajectory were recorded. Concussed individuals demonstrated differences in gait while performing single-task level walking and while being challenged with a more difficult secondary task compared to normal controls. Concussed individuals adopted a slower, more conservative gait strategy to maintain stability, but still exhibited signs of instability with center of mass deviations in the coronal plane increasing by 13% during the question and answer dual-task and 26% more than control subjects. Trends of attentional deficits were present with the question and answer task, while the reaction time task seemed to help concussed individuals be more alert to their gait and stability. Recommendations for a sensitive testing protocol of deficits following concussion are explained.

Tracking the recovery of visuospatial attention deficits in mild traumatic brain injury.

Abstract: The goal of the current investigation was to probe the deficits in the alerting, orienting and executive components of visuospatial attention in individuals who have recently suffered a mild traumatic brain injury (mTBI) and to assess the rate and degree of recovery for each of these components over a month post-injury. A group design was employed to assess and compare the performance of participants (12 males, 8 females; mean age: 21 ± 1.74 years) identified with mTBI relative to control subjects matched for gender, age, height, weight and activity level. Participants performed the attentional network test, designed to isolate the constituents of attention into alerting, orienting and executive components. Reaction times (RTs) and response accuracy were the main dependent variables. The results showed that the orienting and executive components were significantly affected by mTBI immediately after the injury, whereas the alerting component was not. Furthermore, participants with mTBI recovered from the deficits in the orienting component of attention within a week of their injury, whereas the deficits in the executive component remained throughout the month post-injury. In addition, the RT cost to generate accurate compared with inaccurate responses was significantly larger in participants with mTBI than in controls, and this difference was maintained throughout the 1 month testing period. These findings indicate that the regions of the brain associated with the orienting and executive components of visuospatial attention may be most susceptible to neural damage resulting from mTBI. Moreover, the lack of recovery in the executive component indicates that the degree and time course for recovery may be regionally specific.

The Theory of Event Coding (TEC): a framework for perception and action planning.

Abstract: Traditional approaches to human information processing tend to deal with perception and action planning in isolation, so that an adequate account of the perception-action interface is still missing On the perceptual side, the dominant cognitive view largely underestimates, and thus fails to account for, the impact of action-related processes on both the processing of perceptual information and on perceptual learning On the action side, most approaches conceive of action planning as a mere continuation of stimulus processing, thus failing to account for the goal-directedness of even the simplest reaction in an experimental task We propose a new framework for a more adequate theoretical treatment of perception and action planning, in which perceptual contents and action plans are coded in a common representational medium by feature codes with distal reference Perceived events (perceptions) and to-be-produced events (actions) are equally represented by integrated, task-tuned networks of feature codes – cognitive structures we call event codes We give an overview of evidence from a wide variety of empirical domains, such as spatial stimulus-response compatibility, sensorimotor synchronization, and ideomotor action, showing that our main assumptions are well supported by the data

The role of executive function and attention in gait

Abstract: Until recently, gait was generally viewed as a largely automated motor task, requiring minimal higher-level cognitive input. Increasing evidence, however, links alterations in executive function and attention to gait disturbances. This review discusses the role of executive function and of attention in healthy walking and gait disorders while summarizing the relevant, recent literature. We describe the variety of gait disorders that may be associated with different aspects of executive function, and discuss the changes occurring in executive function as a result of aging and disease as well the potential impact of these changes on gait. The attentional demands of gait are often tested using dual tasking methodologies. Relevant studies in healthy adults and patients are presented, as are the possible mechanisms responsible for the deterioration of gait during dual tasking. Lastly, we suggest how assessments of executive function and attention could be applied in the clinical setting as part of the process of identifying and understanding gait disorders and fall risk.

National Athletic Trainers' Association Position Statement: Management of Sport Concussion

Abstract: Objective: To provide athletic trainers, physicians, and other health care professionals with best-practice guidelines for the management of sport-related concussions. Background: An estimated 3.8 ...