About
56
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Introduction
I am a movement scientist, and manage the posture and gait lab of the Department of Health Sciences of Brunel University London. My research focuses on the influence of cognitive and psychological factors on postural stability during standing and walking in older adults and neurological populations. Using different measurement techniques (e.g. EMG, force plate analyses) we try to parcel out the complex mechanisms governing healthy and pathological balance control.
Additional affiliations
March 2019 - present
January 2018 - December 2018
September 2012 - November 2018
Education
September 2011 - September 2012
September 2006 - December 2010
Publications
Publications (56)
Objective:
This study aimed to assess if external focus instructions result in greater improvements in motor skill and automaticity compared to internal focus instructions in stroke patients.
Design:
Double-blind randomized controlled trial.
Setting:
Inpatient stroke rehabilitation unit.
Subjects:
A total of 63 stroke patients (Meanage = 59.6 ± 10....
Older adults rely increasingly on conscious processes to control balance. While this could be in response to age-related declines in balance capacity, it is unclear whether such strategy is adaptive or not. We investigated whether balance capacity modified the effects of conscious movement processing (CMP) on postural control in older adults. Forty...
Freezing of gait (FOG) can severely compromise daily functioning in people with Parkinson’s disease. Inability to initiate a step from FOG is likely underpinned, at least in part, by a deficient preparatory weight-shift. Conscious attempts to weight-shift in preparation to step can improve success of initiating forward steps following FOG. However,...
Purpose:
Concerns about falling are common in older adults and often cause activity restriction. This can lead to physical deconditioning, falls and social isolation. However, not every concerned older adult will restrict their activities. This 12-month longitudinal study investigated the physical and psychosocial factors that predict the new onse...
Dysfunctional breathing (DB) is common among people with and without primary respiratory pathology. While anxiety can contribute to DB, the underpinning mechanism is unclear. One explanation is that anxiety induces conscious, vigilant monitoring of breathing, disrupting ‘automatic’ breathing mechanics. We validated a new tool that quantifies such b...
Background and Objectives: Vigilance towards balance has been proposed to underpin various chronic dizziness disorders, including Persistent Postural Perceptual Dizziness (PPPD). The objective of this study is to develop (through patient input) a validated balance-specific measure of vigilance that comprehensively assesses the varied ways in which...
Background:
fear of falling is common in older adults and can have a profound influence on a variety of behaviours that increase fall risk. However, fear of falling can also have potentially positive outcomes for certain individuals. Without progressing our understanding of mechanisms underlying these contrasting outcomes, it is difficult to clini...
Many studies have shown that focusing on an intended movement effect that is farther away from the body (distal external focus) results in performance benefits relative to focusing on an effect that is closer to the body (proximal external focus) or focusing on the body itself (internal focus) (see, Chua, Jimenez-Diaz, Lewthwaite, Kim & Wulf, 2021)...
Introduction and Objectives
Dysfunctional breathing (DB) is common among people with and without primary respiratory pathology. While anxiety is known to contribute to DB, the underpinning mechanisms are unclear. One likely explanation is that anxiety induces excessive conscious monitoring of breathing, which disrupts ‘automatic’ breathing mechanic...
Maintaining balance is thought to primarily occur sub-consciously. Occasionally, however, individuals will direct conscious attention towards balance, e.g., in response to a threat to balance. Such conscious movement processing (CMP) increases the reliance on attentional resources and may disrupt balance performance. However, the underlying changes...
This study examined the effects of explicit versus implicit learning methods on motor learning and self-efficacy of 11-to 14-year old students (n = 81) practicing the basketball layup during physical education. The main aim was to test the effects of students' verbal working memory capacity (WMC) and propensity for conscious motor processing (CMP)...
Introduction
Breathing pattern disorder (BPD) is an abnormal breathing pattern associated with biochemical, biomechanical and psychophysiological changes. While physiotherapy is often offered, limited evidence-based therapies for BPD are available. Music therapy-based singing exercises have been shown to improve quality of life for individuals with...
Context
Visual biofeedback has been shown to facilitate injury-resistant movement acquisition in adolescent athletes. Visual biofeedback is typically thought to foster implicit learning, by stimulating athletes to focus attention externally (on movement outcome). However, biofeedback may also induce explicit learning, if the athlete uses the visual...
Dysfunctional breathing (DB) is common among people with and without primary respiratory pathology. While anxiety contributes to DB, the underpinning mechanism is unclear. One explanation is that anxiety induces excessive conscious monitoring of breathing, disrupting ‘automatic’ breathing mechanics. We validated a new tool that quantifies such brea...
Maintaining balance typically occurs sub-consciously. Occasionally, however, individuals will direct conscious attention towards balance, e.g., in response to a postural threat. Such conscious movement processing (CMP) increases the reliance on attentional resources and may disrupt control of balance, but the underlying changes in neuromuscular con...
The ‘two-system’ view of fear builds on traditional conceptualisations of emotion; proposing that the mechanism(s) responsible for behavioural and physiological responses to threat may be distinct from that underpinning the (conscious) emotional experience itself. We empirically tested this notion within a novel, applied context of social and econo...
Background:
Energy cost of walking (ECw) is an important determinant of walking ability in people with a lower-limb amputation. Large variety in estimates of ECw has been reported, likely because of the heterogeneity of this population in terms of level and cause of amputation and walking speed.
Objectives:
To assess (1) differences in ECw betwe...
This study examined the effects of explicit versus implicit instructions and feedback methods on motor learning and perceived competence of 9-13-year old students with special educational needs practicing a balancing task during Physical Education. The aim was to test if and how the effects of type of instruction and feedback methods were influence...
Background
Persistent dizziness without a clear cause is common in older adults. We explored whether an anxiety-driven preoccupation with consciously processing balance may underpin the distorted perceptions of unsteadiness that characterises ‘unexplained’ dizziness in older adults.
Methods
We experimentally induced anxiety about losing one’s bala...
Background
Overly cautious gait is common in older adults. This is characterised by excessively slow gait, shortened steps, broadened base of support and increased double limb support. The current study sought to (1) evaluate if overly cautious gait is associated with attempts to consciously process walking movements, and (2) explore whether an ind...
Background:
Energy cost of walking (ECw) is an important determinant of walking ability and participation of people after lower limb amputation [1]. It has frequently been found that people after lower limb amputation have increased ECw compared to able-bodied individuals [2,3]. However, large variety in estimates of ECw are reported in literature,...
Objectives:
Older adults anxious about falling will often consciously process walking movements in an attempt to avoid falling. They also fixate their gaze on the present step rather than looking ahead to plan future actions. The present work examined whether conscious movement strategies result in such restricted visual planning.
Methods:
A tot...
Introduction
Changes in visual attention have been argued to influence freezing of gait (FOG) in people with Parkinson’s Disease (PD). However, the specific visual search patterns of people with FOG pathology (PD + FOG) and potential underlying mechanisms are not well understood. The current study explored visual search behavior in PD + FOG while w...
The ability to perform dual-tasks while moving is often impaired in people with stroke. The aim of this thesis was to investigate the potential of implicit motor learning interventions to target this problem. The rationale was that implicit motor learning should result in relatively automatic movements and thereby enhance dual-task performance in s...
Background: Implicit motor learning is considered to be particularly effective for learning sports-related motor skills. It should foster movement automaticity and thereby facilitate performance in multitasking and high-pressure environments. To scrutinize this hypothesis, we systematically reviewed all studies that compared the degree of automatiz...
Funnel plot of included studies.
NB: Only comparisons for which standard deviations were available could be included in the funnel plot. Assessment was conducted on the difference in absolute motor dual-task performance (X-axis) between implicit and explicit groups at the latest reported test-phase; experiments with positive value on X-axis indicat...
Search strategy.
Example of the search strategy for Medline.
(DOCX)
Functional variability has been suggested to reflect movement automaticity. To test this hypothesis, we used the Uncontrolled Manifold (UCM) approach to operationalize functional variability in darts. We gauged the association between movement automaticity and functional variability in four different ways. First, we investigated whether functional...
Background:
Many stroke patients are inclined to consciously control their movements. This is thought to negatively affect patients' motor performance, as it disrupts movement automaticity. However, it has also been argued that conscious control may sometimes benefit motor performance, depending on the task or patientś motor or cognitive capacity....
We compared the effects of conscious monitoring and control on motor performance. Participants were instructed to adopt an internal or external focus of attention in different blocks of a darts task. For one group, the internal as well as external focus instructions emphasized monitoring. For another group, the instructions emphasized control in th...
Purpose: People without neurological impairments show superior motor learning when they focus on movement effects (external focus) rather than on movement execution itself (internal focus). Despite its potential for neurorehabilitation, it remains unclear to what extent external focus strategies are currently incorporated in rehabilitation post-str...
Many stroke patients experience difficulty with performing dual-tasks. A promising intervention to target this issue is implicit motor learning, as it should enhance patients' automaticity of movement. Yet, although it is often thought that implicit motor learning is preserved post-stroke, evidence for this claim has not been systematically analyse...
Funnel Plot of Included Studies.
Studies were pooled for the main outcome (“Can patients with stroke learn motor tasks implicitly?”). For each study, its effect estimate (standard mean difference of performance in random versus repeated block; SMD) is plotted against its precision (standard error of the SMD; SE). The resulting symmetrical distribut...
Search Strategy.
Example of the search strategy for Medline.
(DOCX)
Appendices A-C with Modified Newcastle Ottawa Scales. The three different Newcastle Ottawa Scales used to assess studies’ risk of bias for each of the three research questions. Of note, for each NOS-scale the items on performance bias rated studies’ quality on their success of blinding participants (i.e., the amount of explicit knowledge that parti...
The authors investigated the relative effectiveness of different attentional focus instructions on motor learning in primary school children. In addition, we explored whether the effect of attentional focus on motor learning was influenced by children's age and verbal working memory capacity. Novice 8–9-year old children (n = 30) and 11–12-year-old...
Background: After stroke, many patients undergo intensive rehabilitation therapy to re-acquire motor skills like walking or grasping. Observational studies suggest that therapists pre- dominantly rely on so-called explicit motor learning strategies during this rehabilitation period. Explicit motor learning may not be the optimal learning strategy f...
Introduction:
After stroke, many patients undergo intensive rehabilitation therapy to reacquire motor skills like walking or grasping. Observational studies suggest that therapists predominantly rely on so-called explicit motor learning strategies during this rehabilitation period. Explicit motor learning may not be the optimal learning strategy f...
Purpose: Stroke survivors are inclined to consciously control their movements, a phenomenon termed "reinvestment". Preliminary evidence suggests reinvestment to impair patients' motor recovery. To investigate this hypothesis, an instrument is needed that can reliably assess reinvestment post-stroke. Therefore, this study aimed to validate the Movem...
Dual-task performance is often impaired after stroke. This may be resolved by enhancing patients' automaticity of movement. This study sets out to test the constrained action hypothesis, which holds that automaticity of movement is enhanced by triggering an external focus (on movement effects), rather than an internal focus (on movement execution)....
Introduction
Stroke survivors are prone to consciously control their movements. Technically, this is referred to as “reinvestment”. Reinvestment has been suggested to impair patients’ motor performance and increase risk of falling. To verify this hypothesis, an instrument is needed that can reliably assess reinvestment post-stroke. The Movement-Spe...
An external focus of attention has been shown to result in superior motor performance compared to an internal focus of attention. This study investigated whether this is due to enhanced levels of movement automatization, as predicted by the constrained action hypothesis (McNevin, Shea, & Wulf, 2003). Thirty healthy participants performed a cyclic o...
