Marjorie Woollacott

Marjorie Woollacott
University of Oregon | UO · Department of Human Physiology

Doctor of Philosophy

About

214
Publications
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Introduction
Skills and Expertise

Publications

Publications (214)
Article
Full-text available
Physical and mental training are associated with positive effects on executive functions throughout the lifespan. However, evidence of the benefits of combined physical and mental regimes over a sedentary lifestyle remain sparse. The goal of this study was to investigate potential mechanisms, from a source-resolved event-related-potential perspecti...
Article
The purpose of this study was to create a detailed characterization of the nature of the sensory perceptions associated with after-death communication. A primary aim was to determine if perceptions of after-death communication (ADC) support one or more of three hypotheses: 1) they are the result of hallucinations or day-to-day thoughts about the de...
Article
There is a paucity of research examining the phenomenology and energetic effects of spiritually transformative experiences with an energetic component, often referred to as kundalini awakenings (KAs). This limits our ability to understand and support individuals who have these often unexpected and powerful experiences. This study aimed to explore n...
Article
Aim: Children with moderate-severe cerebral palsy (CP) show postural control deficits that affect their daily activities, like reaching. The Seated Postural and Reaching Control test (SP&R-co) was developed to address the need for clinical measures that objectively identify dimensions of postural imbalance and corresponding reaching limitations in...
Article
Full-text available
When cognitive load is elevated during a motor task, cortical inhibition and reaction time are increased; yet, standing balance control is often unchanged. This disconnect is likely explained by compensatory mechanisms within the balance system such as increased sensitivity of the vestibulomotor pathway. This study aimed to determine the effects of...
Article
The authors investigated postural and arm control in seated reaches while providing trunk support at midribs and pelvic levels in adults. Kinematics and electromyography of the arm and ipsiliateral and contralateral paraspinal muscles were examined before and during reaching. Kinematics remained constant across conditions, but changes were observed...
Article
Purpose: To determine whether segmental training is more effective in improving gross motor function in children and young people with moderate-to-severe cerebral palsy than conventional physiotherapy. Methods: Twenty-eight participants were randomized to a segmental training or control group. Outcomes were Gross Motor Function Measure (GMFM), P...
Article
Full-text available
Appropriate reactive motor responses are essential in maintaining upright balance. However, little is known regarding the potential location of cortical sources that are related to the onset of a perturbation during single- and dual-task paradigms. The purpose of this study was to estimate the location of cortical sources in response to a whole-bod...
Conference Paper
Full-text available
Human cognitive capacity is mediated by synergistic interactions between multiple physiological variables: including genetic and epigenetic potential, nutrition status, gender, race, age, cardiovascular capacity, neural function, and physical activity type and amount. These affect attention, memory, decision-making, educational outcomes, personalit...
Article
Background: External support has been viewed as an important biomechanical constraint for children with deficits in postural control. Nonlinear analysis of head stability is necessary to confirm benefits of interaction between external trunk support and level of trunk control. Objective: To compare the effect of biomechanical constraints (trunk...
Article
Full-text available
Purpose: To test the effects of segmental trunk support on seated postural and reaching control in children with cerebral palsy. Methods: Seventeen children (age range 2-15 y, Gross Motor Function Classification System levels III-V) were classified with the Segmental Assessment of Trunk Control into mild (complete trunk control/lower lumbar defi...
Article
People with Parkinson's disease (PD) are encouraged to participate in physical activity levels equivalent to those recommended for the general population. Understanding factors that influence this activity is important for facilitating this participation. This study examined factors associated with participation in moderate and high intensity daily...
Article
Figure Figure44 of the article by Rachwani et al. (2015) contained a minor error, which we hereby rectify. In the original figure, the graph displaying the number of movement units across sitting development is incorrect (bottom graph on the left column). We therefore re-submit Figure Figure44 with the correct graph. We sincerely apologize for the...
Article
Global measures of trunk sway are traditionally used even though the trunk comprises a multiple number of segments. The authors' aim was to measure the seated sway of typically developing children using a multisegment approach. Twenty typically developing children divided into 2 groups, older and younger than 10 years old, participated in this stud...
Article
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The development of reaching is crucially dependent on the progressive control of the trunk, yet their interrelation has not been addressed in detail. Previous studies on seated reaching evaluated infants during fully supported or unsupported conditions; however, trunk control is progressively developed, starting from the cervical/thoracic followed...
Article
To examine postural constraints in children with moderate-to-severe cerebral palsy using a segmental approach. quasi-experimental repeated measure study; case series SETTING: Motor control research laboratory PARTICIPANTS: Fifteen children (4-16 years) with moderate (Gross Motor Function Classification System (GMFCS) IV; n=8; 4 males) or severe (GM...
Conference Paper
This study addresses how adults control their arm and sitting posture during a reach-to-grasp task, while providing segmental trunk support. We analyzed the kinematic and neuromuscular patterns of the arm and trunk before and during the reaching task while providing trunk support at two levels: mid-rib and pelvic. Fifteen seated healthy adults reac...
Article
AimImprovement of gross motor function and mobility are primary goals of physical therapy in children with cerebral palsy (CP). The purpose of this study was to investigate the relationship between segmental control of the trunk and the corresponding gross motor function in children with CP.Method This retrospective cross-sectional study was based...
Article
Full-text available
: We report the first controlled study of Tai Chi effects on the P300 event-related potential, a neuroelectric index of human executive function. Tai Chi is a form of exercise and moving meditation. Exercise and meditation have been associated with enhanced executive function. This cross-sectional, controlled study utilized the P300 event-related p...
Article
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The study used a dual-task (DT) postural paradigm (two tasks performed at once) that included electroencephalography (EEG) to examine cortical interference when a visual working memory (VWM) task was paired with a postural task. The change detection task was used, as it requires storage of information without updating or manipulation and predicts V...
Article
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When a cognitive and a motor task like walking or keeping one's balance are performed concurrently, performance usually deteriorates. Older adults have often been shown to prioritize their motor performance in such dual-task situations, possibly to protect themselves from falls. The current study investigates whether these prioritization behaviors...
Article
Full-text available
Stringed instrument bowing is a complex coordinative motor skill acquired though years of intense practice. We apply a novel "freezing" analysis to investigate how movement at different joints contributes to bow transport (movement amplitude), stabilization of bow parameters (angle, velocity) during bow movements, and quick reversals of bow directi...
Data
Full-text available
Falls represent a significant health risk in the elderly and often result in injuries that require medical attention. Reduced ability to control motion of the whole-body center of mass (COM) has been shown to identify elderly people at risk of falling. To explore effective preventive strategies and interventions, we studied adult age-related differ...
Book
Motor Control is the only text to bridge the gap between current motor control research and its applications to clinical practice. The text prepares therapists to examine and treat patients with problems related to balance, mobility, and upper extremity function, based on the best available evidence supporting clinical practice. This edition provid...
Article
Full-text available
Since most working memory (WM) tasks used in dual-task (DT) postural paradigms include both storage and processing of information, it is difficult to determine the extent to which each of these contributes to interference with balance control. In the current study, a change-detection task (changes in colored squares between two presentation events)...
Article
Full-text available
Abstract This cross-sectional field study documented the effect of long-term t'ai chi, meditation, or aerobic exercise training versus a sedentary lifestyle on executive function. It was predicted that long-term training in t'ai chi and meditation plus exercise would produce greater benefits to executive function than aerobic exercise. T'ai chi and...
Article
This study compared central nervous system organizational processes underlying balance in children of three age groups: 15-31 months, 4-6 years, and 7-10 years, using a movable platform capable of antero-posterior (A-P) displacements or dorsi-plantar flexing rotations of the ankle joint. A servo system capable of linking platform rotations to A-P s...
Article
Full-text available
This study aimed to investigate movement accuracy of experienced cellists, the statistical properties of their note sequences during a reciprocal task, and the degree to which these movement characteristics depend on auditory feedback. Nine experienced cellists were asked to shift alternately between two notes using only their index finger to make...
Article
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There is evidence that long-term experience can promote functional changes in infants. However, much remains unknown about how a short-term experience affects performance of a task. This study aims to investigate the influence of a single training session at the onset of goal-directed reaching on the spatio-temporal parameters of reaching and wheth...
Article
Full-text available
This study explored the influence of an external support at the thoracic and pelvic level of the trunk on the success of reaching, postural stability and reaching kinematics while infants reached for a toy. Seventeen infants (4-6 months) were clustered into two groups according to their trunk control assessed with the Segmental Assessment of Trunk...
Article
Full-text available
Theoretical and empirical evidence suggests that accurate and efficient motor performance may be achieved by task-specific exploitation of biomechanical degrees of freedom. We investigate coordination of the right arm in a task requiring a sudden yet precisely controlled reversal of movement direction: bow reversals during continuous ("legato") ton...
Article
Functional base of support (FBOS), the effective area for center of pressure (COP) movement, decreases with aging, which would reduce one's ability to restore balance during perturbed stance. We investigated the relationship between ankle muscle strength and FBOS as well as the threshold perturbation acceleration that required a heel-rise (HR) or s...
Article
Full-text available
Stringed instrument bowing is a complex sensorimotor skill, involving fine regulation of bow orientation and motion relative to the string. In this study, we characterize this skill in terms of stabilization of specific bow parameters as well as the underlying use and coordination of the degrees of freedom (DOF) of the right bowing arm. Age-matched...
Article
Full-text available
The question of how infants attain upright sitting is at the core of understanding the development of most functional abilities. Our simple, practical method of securing the hips and different trunk segments while evaluating the infant's ability to vertically align and stabilize the trunk in space contributes a useful method and new insights into t...
Article
Full-text available
Falls represent a significant health risk in the elderly and often result in injuries that require medical attention. Reduced ability to control motion of the whole-body center of mass (COM) has been shown to identify elderly people at risk of falling. To explore effective preventive strategies and interventions, we studied adult age-related differ...
Article
Full-text available
People with Parkinson's disease often have walking difficulty, and this is likely to be exacerbated while walking in places in the community, where people are likely to face greater and more varied challenges. This study aims to understand the facilitators and the barriers to walking in the community perceived by people with Parkinson's disease. Th...
Article
The purpose of this study was to investigate the typical development of postural control in younger (5-6 yrs) and older (7-16 yrs) children (YTD and OTD) during two gait tasks, including level walking and obstacle-crossing, using a dual-task paradigm, and to compare the results of the children's performance with that of healthy young adults (HYA)....
Article
Full-text available
Previous research using dual-task paradigms indicates balance-impaired older adults (BIOAs) are less able to flexibly shift attentional focus between a cognitive and motor task than healthy older adults (HOA). Shifting attention is a component of executive function. Task switch tests assess executive attention function. This multivariate study aske...
Article
Full-text available
Difficulty performing more than one task at a time (dual tasking) is a common and disabling problem experienced by people with Parkinson disease (PD). If asked to perform another task when walking, people with PD often take shorter steps or walk more slowly. Currently there is uncertainty about whether clinicians should teach people with PD to avoi...
Article
The purpose was to assess differences in postural response characteristics between two groups of elite athletes having power or endurance training. Participants were all men and included power- (M age = 21 yr., SD = 3, n = 12) and endurance-trained (M age = 22, SD = 3, n = 12) athletes. Muscle response characteristics and center of pressure measure...
Article
The Segmental Assessment of Trunk Control (SATCo) provides a systematic method of assessing discrete levels of trunk control in children with motor disabilities. This study refined the assessment method and examined reliability and validity of the SATCo. After refining guidelines, 102 video recordings of the SATCo were made of 8 infants with typica...
Article
Full-text available
Deficits in postural control are one of the hallmarks of disability in children with cerebral palsy (CP). Yet, much remains unknown regarding the etiology of postural deficits in these children. Here we evaluated postural control at a simplified task level by measuring head stability during quiet sitting while systematically manipulating the level...
Article
To compare the effect of 3 different approaches to balance training on dual-task balance performance in older adults with balance impairment. A double-blind, randomized controlled trial. University research laboratory. Older adults (N=23) with balance impairment (mean age, 74.8y). They scored 52 or less on the Berg Balance Scale (BBS) and/or walked...
Article
The purpose of this study was to compare the efficiency of three different balance training strategies in an effort to understand the mechanisms underlying training-related changes in dual-task balance performance of older adults with balance impairment. Elderly individuals with balance impairment, age 65 and older, were randomly assigned to one of...
Article
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Recent research has explored dual-task deficits during locomotion in older adults, yet the mechanisms underlying these deficits are poorly understood. In the current study, we examined one possible factor contributing to these deficits, the inability to flexibly allocate attention between two tasks. Twelve healthy young adults and 12 healthy elderl...
Article
Recent research has begun to explore the ability of older adults to perform balance tasks while simultaneously performing a secondary cognitive task; however, it has suffered from limitations regarding the mechanisms underlying the problems that cause dual-task deficits in older adults with balance impairments. Two possible attentional mechanisms (...
Article
Older adults can improve several components of their balance such as timed stance ability by participating in a short specific exercise program. However, it is not clear whether participation in more frequent and intense training can result in improved reactive balance performance in older adults. Optimal reactive responses are required to prevent...
Article
Full-text available
Reaching to grasp an object of interest requires complex sensorimotor coordination involving eye, head, hand and trunk. While numerous studies have demonstrated deficits in each of these systems individually, little is known about how children with cerebral palsy (CP) coordinate multiple motor systems for functional tasks. Here we used kinematics,...
Article
Full-text available
To investigate dual-task interference between a concurrent cognitive task (auditory Stroop test) and obstacle avoidance in older adults with or without a history of falls. Gait performance (temporal-distance parameters, range of motion and peak velocity of the center of mass) and verbal reaction time (VRT) in the secondary auditory Stroop task were...
Article
Full-text available
Based on a newly developed method that combines finger position tracking and spectral analysis of the concurrent acoustic record, we studied the accuracy and variability of pitch performance in eight skilled cellists and the role of acoustic feedback in their performance. The tasks required shifting movements between pairs of notes and separated by...
Article
To investigate the interference between a secondary task and a postural task in children with cerebral palsy (CP). In this exploratory study, a dual-task paradigm was used in which children stood in either a wide or a narrow stance position while simultaneously performing a visual working memory task calibrated to be of equitable attentional demand...
Article
The current investigation aimed to contrast the level and quality of dual-task interactions resulting from the combined performance of a challenging primary postural task and three specific, yet categorically dissociated, secondary central executive tasks. Experiments determined the extent to which modality (visual vs. auditory) and code (non-spati...
Article
Full-text available
The authors examined the interaction between the development of postural control and the development of the executive function of attention in 13 children and 6 adults in dual-task conditions. Participants performed an attentionally demanding cognitive task and a postural task simultaneously. The authors equalized the attentional load of the cognit...
Article
Full-text available
Research on attention and gait stability has suggested that the process of recovering gait stability requires attentional resources, but the effect of performing a secondary task on stability during obstacle avoidance is poorly understood. Using a dual-task paradigm, the present experiment investigated the extent to which young adults are able to r...
Article
Full-text available
The present investigation examined the contributions of specific attentional networks to long-term trait effects of meditation. It was hypothesized that meditation could improve the efficiency of executive processing (inhibits prepotent/incorrect responses) or orientational processing (orients to specific objects in the attentional field). Particip...
Article
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The authors examined and compared the effect of support-surface perturbations of various magnitudes on lower extremity kinetics of 7 children with cerebral palsy (CP) and 8 typically developing (TD) children. Results showed that the highest velocity tolerated without stepping was slower in children with CP than in either age-matched TD or younger T...
Article
Full-text available
Reaching to grasp an object of interest requires a complex sensorimotor transformation-involving eye, head, hand, and postural systems. We show here that discontinuities in development of movement in these systems are dependent not only on age but also vary according to task constraints. Providing external postural support allows us to examine the...
Article
Full-text available
This study investigated differences in reactive balance abilities of typically developing children and those with spastic diplegia. Recovery from balance threats was compared by: (i) Platform velocity and amplitude thresholds: Speed and size of platform movement at which children required assistance to remain upright, (ii) percentage of trials with...
Article
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In this paper, we demonstrate that when a peripheral object is foveated by a sequence of multiple saccades, the initial saccade in the sequence is initiated markedly faster than a single accurate saccade to the same object. We suggest that multiple saccades represent a more automatic form of oculomotor planning that may be the result of a reduced i...
Article
This study examined the effect of Tai Chi (TC) training on biomechanical responses to large, fast walking perturbations in balance-impaired seniors. Twenty-two seniors (age 68-92, BERG 44 or less) with surgical interventions to knees, hips, and back were randomly divided into control or TC groups. Groups trained 1.5h/day, 5 days/week for 3 weeks. C...