Longitudinal analysis of gait in people with Parkinson’s disease to improve the detection of risk of falls

Within 3 years of diagnosis, more than 85% of people with Parkinson’s disease (PD) develop gait problems, which may lead to falls resulting in serious injury and reduced quality of life. The evolution of gait impairments with PD progression and the relationship between locomotor performance and falls in PD are unclear. In addition, large individual variations exist at the level of gait performances corresponding to specific levels of disease severity. Deficits in cognitive and sensory-motor functions in PD also impair the ability to walk while doing another task (i.e., dual-tasking). When attentional resources in PD patients are allocated to more than one task, gait abnormalities increase. This suggests that dual-task walking may present a higher sensitivity to predict future falls in PD patients. The goals of this project are 1) to determine the effects of an attention-demanding task (i.e., phoneme monitoring) on gait in PD patients and age-matched controls, 2) to characterize within-participant changes of gait performance over six-month intervals and their relationship to changes in cognition, and 3) to predict near falls, falls and mobility impairments occurring during a one-year follow-up period in PD patients based on baseline gait performance. The longitudinal design of this study consists in assessing gait during single and dual-task walking every six months, and to collect information about falls and near falls. This project will improve the objective assessment of fall risk in PD patients using gait parameters during cognitively challenging conditions, similar to those experienced in patient’s daily life

NEURAL MECHANISMS UNDERLYING SENSORIMOTOR SYNCHRONIZATION WITH DIFFERENT FORMS OF RHYTHMS

Neural activity exhibits non-periodic rhythm [2] but it is unknown if neural activity synchronizes with non-periodic rhythms, as it does with periodic rhythms [1]. The purpose of this research is to determine the neural mechanisms present leading to synchronized finger tapping to varying rhythms. Twenty healthy young adults tapped their finger on a pressure sensitive pad, listened to metronomes, and wore a electroencephalogram (EEG) during synchronized finger tapping tasks (periodic, fractal, and random). Inter-tap intervals (ITIs), inter-beat intervals (IBIs), and frequency tags were used as the behavioral and cortical synchronization with the metronome. One-way ANOVAs were used to determine differences between the peak cortical frequencies present during synchronization and the frequency of the metronome. The periodic rhythm stimulated the most prominent peak in most participants. Mean frequency of the fractal and periodic metronomes were similar between brain activity and the metronome for the Oz electrode. The peak frequencies in the fractal and random conditions are difficult to identify in all participants and is requiring more detailed identification processes. The identification of these frequencies will be based on the identification of the peak frequencies present from the metronome and the distribution of amplitudes at those frequencies, as they are expected to be present in cortical recordings. The results of this work support evidence that brain activity synchronizes with periodic metronomes and may with variable metronomes to a lesser magnitude, as the stimulus is less strong at a single frequency

Post-Activation Potentiation: Decay or Fatigue Delay

Post-activation potentiation has been shown to improve jumping performance and other ballistic activities. The improvements in performance have been attributed to four main mechanisms, but the most important mechanism to the current study is the improvement in neural activity that leads to greater levels of potentiation. Post-activation potentiation has been shown to be stimulated by a maximal activity, called a conditioning contraction, and can be used as a warm up. In studies that have not shown the effects of post-activation potentiation, the proposed reason is fatigue, but the interaction of post-activation potentiation and fatigue have not been thoroughly tested. The purpose of this study was to assess the interaction of fatigue and post-activation potentiation. The present study tested recreational, healthy, lower body resistance trained participants who took part in 3 days of testing (familiarization/baseline testing and 2 fatigue test days). The results of the current study showed no significant difference between the control and experimental days for any of the variables measured. The results of this study demonstrate that the use of a conditioning contraction during a warm up protocol will not be a detriment to performance during repeated jumps and could be used in a warm up. The present study may have been limited by a small number of participants, individual variation, and training status of the participants

Neural Mechanisms Underlying Sensorimotor Synchronization with Different Forms of Rhythms

Introduction: Neural activity exhibits non-periodic rhythm [2] but it is unknown if neural activity synchronizes with non-periodic, as it does with periodic rhythms [1]. The purpose of this research is to determine the neural mechanisms present leading to synchronized finger tapping to varying rhythms. Methods: Twenty young healthy adults will be recruited to participate in the present study (see Figure 1 for the protocol). Electroencephalography (EEG) will be used to measure the amplitude (AE) and beats for interbeat intervals (IBIs), and a pressure sensor will be used to measure intertap intervals (ITIs). The AE will be assessed for activity spike timing called event related potentials (ERPs) to allow for assessment for differences in neural activity timing with a two-way analysis of variance. The AE, ITIs, and IBIs will be assessed with detrended fluctuation analysis (DFA) and compared with a pearson-r correlation. Results and Discussion: Data for the present study is currently in the process of being collected. The DFA of the IBIs, ITIs, ERP, and AE are expected to match to varying degrees but the fractal condition is expected to present the greatest degree of synchronization. Conclusions: This research will give insight into the ability of the brain to complexity match to not only recreate the rhythm of auditory signals within the brain but also with behavior. Fractal and isochronous metronomes may be more readily matched within the brain and behavior because they are more biologically relevant and predictable than the random metronome

EFFECTS OF THE SPEEDMAKER DEVICE ON MUSCLE ACTIVITY AND VERTICAL JUMP PERFORMANCE

This study examined the effects of the SpeedMaker device versus a control condition on jump performance and muscle activity (MA). Female collegiate lacrosse and track athletes (n=16) performed three 45 m sprints at increasing intensities of 80, 90, and 100% of maximum sprint speed either wearing the device or in a control condition. Two minutes after the sprints, athletes performed three maximal countermovement jumps (CMJ) without the device. Variables examined were flight time (FT), peak ground reaction force (PGRF), rate of force development (RFD) and MA during the CMJ. Compared to the control condition, the SpeedMaker device displayed higher PGRF and RFD (p \u3c 0.05). There was no difference (p \u3e 0.05) for FT or for MA. The SpeedMaker device enhanced some factors affecting jump flight time, but ultimately did not increase flight time or muscle activity

ACUTE EFFECTS OF THE SPEEDMAKER RESISTIVE SPRINT DEVICE: ELECTROMYOGRAPHY AND KINEMATICS

The SpeedMaker resistive sprint device is claimed to elicit post-activation potentiation, improve knee height and upper leg drive to improve sprint performance. There was a total of 9 participants in the present study. The participants were tested on two days for changes in knee and hip angles, sprint times and changes in muscular activation. The present study found no presence of post-activation potentiation no evidence of changes improved knee height or upper leg drive from the SpeedMaker device. The purpose of the current study was to assess the claims that the SpeedMaker device improves sprint performance. The present study tested 10 female track and field and lacrosse athletes on the effects of this device. The findings of the present study is that the SpeedMaker device may decrease knee angle

ADAPTATIONS TO SPRINTING AND JUMPING AFTER TRAINING WITH A RESISTANCE HARNESS IN TRACK ATHLETES

This study examined the effect of a harness resisting leg movement on sprinting and jumping performance. Split times for 10, 20, 36.58 and 50 meters, kinematics of hip and knee angles during sprinting, forces of maximum countermovement jumps and dualenergy X-ray absorptiometry (DEXA) were measured prior and following five-weeks of training with the resistance device. Results showed significant improvement in 10 m sprint times and knee extension during sprinting following five-weeks training (p\u3c.05). No significant changes in jump or DEXA parameters were seen. Findings of the current study indicate that the SpeedMaker device may improve the acceleration phase of sprinting and stimulate a larger range of motion at the knee joint. Future studies with the device should include longer training periods, greater sample sizes and a measurement of resistance

FINGER TAPPING MAY STIMULATE A GENERAL MECHANISM TO MAKE PEOPLE WITH PARKINSON’S DISEASE WALK FASTER

Timing is a major component of movement slowed by Parkinson’s disease. Movement speed can be momentarily restored by moving in time with metronomes. Recent evidence has suggested that people with Parkinson’s disease only need to perform finger tapping training to a metronome to increase their walking speed after the removal of a metronome, but it is not well known why this is possible nor what effects the amount of transfer from finger tapping to walking. Cross education may cause this transfer and is believed to require the activity of certain areas of the brain (supplementary motor area and premotor cortex), which can be measured with functional near infrared spectroscopy. Comparing walking cadence before and after finger tap training can provide insight about the amount of transfer and having participants reproduce the metronome after it is removed in training will provide insight into the amount of retained movement rate. Walking prior to finger tapping training will provide a speed for the metronomes in training and to test if finger tapping is truly generalized with the same mechanism participants will train with fast metronomes and one slow metronome. As a control, participants will also have to listen to a metronome to determine if the rate generalization is due to finger tap training. Our hypothesis is that the premotor cortex will be active during training, supplementary motor in the post training walk, and these cortical activations will be related to reproduction of movement rate and increased walking speed

BRAIN ACTIVATION DURING SINGLE AND DUAL TASK WALKING IN PEOPLE WITH PARKINSON’S DISEASE

Parkinson’s disease (PD) is a degenerative disease that affects the dopamine-producing neurons on the brain, resulting in tremors, limb rigidity, and gait and balance problems.1 The present study evaluated these symptoms under the constraints of dual-task walking procedures. By introducing the second task while walking, key attentional resources are directed away from walking towards the second task, increasing gait variability and the risk for falls, particularly in those with PD.2 An indicator of this attentional shift is visible via neuroimaging, where the prefrontal cortex shows increased activation during tasks requiring attention. The present study used functional near-infrared spectroscopy (fNIRS) to monitor prefrontal activation during the task procedures in PD patients and healthy older adult controls. Over the course of two visits, participants were introduced to both the single and dual tasks that involved walking and cognitive listening. During the dual-tasks, we also provided instruction for prioritization of one task over another to observe the shift in prefrontal activity during the task. Present analyses show trends we expected to see, including more prefrontal activity during walking tasks compared to healthy older adults, which we are observing in the walking single-task and the cognitive-emphasis dual-task. However, some of the other walking tasks, no-prioritization and walking-prioritization dual-tasks in particular, are showing less prefrontal activity than we anticipate for PD patients compared to controls. Understanding the interaction between attentional prefrontal activity and gait variability, particularly in those with PD, can be extremely beneficial, especially when protecting these populations from fall risks