Jennifer Baird

Knee Valgus During Drop Jumps in National Collegiate Athletic Association Division I Female Athletes: The Effect of a Medial Post

Background Female athletes land from a jump with greater knee valgus and ankle pronation/eversion. Excessive valgus and pronation have been linked to risk of anterior cruciate ligament injury. A medially posted orthosis decreases component motions of knee valgus such as foot pronation/eversion and tibial internal rotation. Hypothesis We hypothesized a medial post would decrease knee valgus and ankle pronation/eversion during drop-jump landings in NCAA-I female athletes. Study Design Controlled laboratory study. Methods Knee and ankle 3-dimensional kinematics were measured using high-speed motion capture in 10 National Collegiate Athletic Association Division I female athletes during a drop-jump landing with and without a medial post. Analysis of variance was used to determine differences in posting condition, t tests were used to determine dominant-nondominant differences, and the Pearson correlation coefficient was used to determine relationships between variables. Results Significant differences were found for all measures in the posted condition. A medial post decreased knee valgus at initial contact (1.24°, P< .01) and maximum angle (1.21 °, P< .01). The post also decreased ankle pronation/eversion at initial contact (0.77°, P < .01) and maximum angle (0.95°, P = .039). Conclusion The authors have demonstrated a significant decrease in knee valgus and ankle pronation/eversion during a drop jump with a medial post placed in the athletes’ shoes. Clinical Relevance A medial post may be a potential means to decrease risk of anterior cruciate ligament injury.

Variability in kinematic coupling assessed by vector coding and continuous relative phase

Variability in the spatio-temporal coordination of human movement kinematics is often assessed by vector coding and continuous relative phase (CRP). To facilitate appropriate comparisons between the findings of studies that have used different techniques to assess variability, the purposes of this study were: (1) to determine if both vector coding and CRP behave according to dynamical systems theories on variability and state space transitions; and (2) to determine if trends in coordination variability during movement are consistent when using either vector coding or CRP. We present both a theoretical case (the Lorenz Attractor) and two experimental cases (rearfoot-forefoot coupling during overground walking for 22 subjects; the effect of treadmill speed on thigh-leg coupling for five subjects). In the theoretical case, variability quantified by CRP agreed with dynamical systems theory on state space transitions more so than variability quantified by vector coding. In experimental cases, this distinction was less clear, although CRP appeared to be a more conservative metric for variability. The magnitudes (all p<0.001) and timings (all p<0.04) of peaks in variability during the stance phase of overground walking depended on whether vector coding or CRP was used for two couplings. Similar distinctions were observed for peaks during the stride cycle of treadmill locomotion (all effect sizes >2.8). However, changes in the average variability during the stride cycle as speed increased were consistent for both methods (all effect sizes <0.2). The results suggest that comparisons between the findings of studies that have quantified variability using CRP and those that have used vector coding should be made with caution.

Young and older adults use different strategies to perform a standing turning task

BACKGROUND Falls are the leading cause of death in adults over 65 years of age. Falls during turning are likely to result in costly and debilitating hip fractures. Two-thirds of adults who fracture a hip will never regain their previous level of independence. The purpose of this study, therefore, was to examine performance of turning in place in young and older adults. METHODS Ten young (mean age=25 years) and 10 community-dwelling older adults (mean age=75 years) performed a standing turning task under two conditions: feet constrained and feet unconstrained. Dependent measures were rotational range of motion of the head-on-trunk, trunk-on-pelvis, pelvis and feet; trunk flexion/extension and knee flexion; and center of pressure range and center of mass range in both the anterior-posterior and medial-lateral directions. FINDINGS In both conditions, older adults used less head-on-trunk but more trunk-on-pelvis rotation than the young adults. In the constrained condition, older adults also used more trunk extension and knee flexion than the young adults. In the unconstrained condition, more of the older adults moved their feet (60% vs. 30% of young adults). These differences in segmental motion resulted in greater center of mass movement for the older adults in the constrained but not the unconstrained foot condition. INTERPRETATIONS Older adults show changes in segmental spinal range of motion associated with postural instability while turning in place. Foot movements play an essential role in compensating for these changes and maintaining postural stability.

Multidisciplinary stroke rehabilitation delivered by a humanoid robot: Interaction between speech and physical therapies

Background: A great number of stroke patients pursue rehabilitation services in multiple domains (e.g., speech, physical, occupational). Although multidisciplinary and interdisciplinary approaches to stroke rehabilitation are considered desirable, it is largely unknown how the intervention in one domain affects the progress in others. Aims: The current study investigated the interaction between speech therapy and physical therapy. Additionally, the feasibility of utilising a humanoid robot in stroke rehabilitation was described. Methods & Procedures: A 72-year-old male chronically challenged by aphasia and hemiparesis completed speech and physical therapy tasks in the sole condition (Speech Only, Physical Only) and in the sequential condition (Speech & Physical). The therapy activities were delivered by a humanoid robot. Outcomes & Results: Greater gains in speech and physical functions were obtained during the sole condition than in the sequential condition, suggesting a competitive interaction between speech and physical therapies. Conclusions: The cross-domain competition can be accounted for by fatigue, participant characteristics, and task characteristics. Objective data on speech and physical functions and subjective data on perceived quality of life indicate positive outcomes in this single case. These findings warrant further research on the feasibility and utility of humanoid robots in stroke rehabilitation.

Towards extended virtual presence of the therapist in stroke rehabilitation

This paper considers the use of humanoid robots in residential stroke care to facilitate both direct and indirect interaction between clients and therapists. Direct interaction is realized through a humanoid-mediated teletherapy where a therapist assesses the motor function of a patient and provides therapy customized to the individual. During the teletherapy sessions, the therapist uses a simple speech interface to program therapeutic behavior and activity. Indirect interaction is implemented by the therapist-programmed artifact where a humanoid robot delivers therapeutic activities to the stroke patient in the absence of the therapist. We propose that such an approach can amplify the outcome per hour of therapist time. Outcome data from the current study indicate that the therapist can successfully provide customized therapy to individuals in residential settings and warrant further study.

Upper-limb exercises for stroke patients through the direct engagement of an embodied agent

In this case study, we examine the functional utility of an embodied agent as an interactive medium in stroke rehab. A set of physical rehab exercises is conducted through the direct engagement of an embodied agent, the uBot-5. Based on the preliminary data, we argue that a general-purpose embodied agent has a potential to functionally complement human therapists in providing rehab to stroke patients.

A follow-up on humanoid-mediated stroke physical rehabilitation

We report the results of standardized tests on a single subject with a stroke at 4, 20 and 28 weeks after completion of the study. These results follow from previous work [1]. The subject demonstrated sustained improvement in motor function 28 weeks after completing the study. In addition to quantitative results, the questionnaire results by the subject and the spouse testify that the subjective user experience was also positive. This further advocates the use of general purpose robots to complement human therapists.0

Cognitive-linguistic effort in multidisciplinary stroke rehabilitation: Decreasing vs. increasing cues for word retrieval

Approximately 24% of stroke survivors experience co-occurring aphasia and hemiparesis. These individuals typically attend back-to-back therapy sessions. However, sequentially scheduled therapy may trigger physical and mental fatigue and have an adverse impact on treatment outcomes. The current study tested a hypothesis that exerting less effort during a therapy session would reduce overall fatigue and enhance functional recovery. Two stroke survivors chronically challenged by non-fluent aphasia and right hemiparesis sequentially completed verbal naming and upper-limb tasks on their home computers. The level of cognitive-linguistic effort in speech/language practice was manipulated by presenting verbal naming tasks in two conditions: Decreasing cues (i.e., most-to-least support for word retrieval), and Increasing cues (i.e., least-to-most support). The participants completed the same upper-limb exercises throughout the study periods. Both individuals showed a statistically significant advantage of decreasing cues over increasing cues in word retrieval during the practice period, but not at the end of the practice period or thereafter. The participant with moderate aphasia and hemiparesis achieved clinically meaningful gains in upper-limb functions following the decreasing cues condition, but not after the increasing cues condition. Preliminary findings from the current study suggest a positive impact of decreasing cues in the context of multidisciplinary stroke rehabilitation.