Professor Bradnam is Associate of the School of Physiotherapy in the Graduate School of Health and an adjunct Professor of Physiotherapy at Flinders University in Adelaide. She is a physiotherapist and neuroscientist with over 16 years of academic experience gained in Australia, New Zealand and the United Kingdom.
Professor Bradnam leads a human neuroscience laboratory, specializing in the use of Transcranial Magnetic Stimulation to study brain function in neurological disorders such as dystonia, upper limb pain and stroke. She has over 40 publications in physiotherapy or neuroscience journals and has contributed to more than 60 national and international conference presentations since 1999.
Her research interests lie in understanding brain mechanisms in neurological and neuromuscular disorders and novel interventions that promote neural plasticity in rehabilitation, such as noninvasive brain stimulation.
Professor Bradnam is an experienced doctoral supervisor and welcomes research degree enquiries via a formal expression of interest (please do not email directly).
- Dystonia Network Australia(DNA) Advisory Board
- Australian Physiotherapy Association (APA) 2011 - present
- Australasian Neuroscience Society (ANS) 2013 - present
- Stroke Society Australia (SSA) 2012 - present
- New Zealand Society of Physiotherapists (NZSP) 1986 - 2011
- Chartered Society of Physiotherapists (CSP) United Kingdom 2003,2005-2007
Can supervise: YES
- Shoulder and upper limb pain
- Chronic pain
- Non-invasive brain stimulation
- Transcranial Magnetic Stimulation
- Translational Neuroscience
- Pain Mechanisms
- Research Project
Bradnam, L, Chen, C, Graetz, L & Loetscher, T 2019, 'Reduced vision-related quality of life in people living with dystonia.', Disability and Rehabilitation, pp. 1-5.View/Download from: Publisher's site
PURPOSE:Dystonia is a neurological movement disorder with negative impact on function and quality of life. It is currently unclear whether vision-related quality of life is affected. The aim of this study was to determine whether vision-related quality of life is reduced by dystonia. MATERIALS AND METHODS:A vision-related quality of life questionnaire was delivered online to probe visual function in people living with dystonia. Scores for each of six domains were compared to normative data of 819 healthy participants using one sample t-tests. Respondents were divided into two groups based on whether they had botulinum toxin injections and compared using independent samples t-tests. RESULTS:There were 42 completed responses. There was a difference from norm for two domains; ocular symptoms (t(41) = 2.31, p = 0.026) and role performance (t(41) = 2.85, p = 0.007). There was variation in responses for all six domains. No difference in scores for the botulinum toxin injection group was found for either domain (both p > 0.74). CONCLUSIONS:Some people with dystonia experience reduced vision-related quality of life, which has potential to contribute to their disability. Health professionals should be aware of vision-related issues when managing people with dystonia and consider appropriate rehabilitative interventions to reduce disability and enhance quality of life. Implications for rehabilitation Dystonia is a neurological movement disorder resulting in abnormal postures and movements. Vision-related quality of life is reduced by dystonia which may contribute to disability and reduced function. Strategies to improve vision-related quality of life should be included in rehabilitation programmes for people living with dystonia.
McCambridge, AB, Zaslawski, C & Bradnam, LV 2019, 'Investigating the mechanisms of acupuncture on neural excitability in healthy adults.', NeuroReport, vol. 30, no. 2, pp. 71-76.View/Download from: Publisher's site
Acupuncture is gaining interest as a potential treatment modality for various neurological conditions. Yet, the underlying mechanisms and efficacy on brain function are not well understood. Therefore, this study investigated the previously proposed hypothesis that acupuncture suppresses motor cortex excitability using transcranial magnetic stimulation (TMS) in healthy adults. The study was randomised, sham-controlled, and double-blinded. Single and paired-pulse TMS was delivered before, during, immediately after, and 30 min after removal of the needle. Acupuncture to the right Hegu acupoint (LI-4) of the hand was delivered by an experienced acupuncturist using standardised manipulations. A disposable (0.22×30 mm, Hwato) needle was used for verum stimulation (penetrating) and a Park retractable needle for sham (nonpenetrating). The peak-to-peak amplitude of TMS-induced motor-evoked potentials was recorded from two intrinsic hand muscles. Needling sensations were quantified using the Massachusett's acupuncture sensation scale. Participant needling sensations were not different between verum or sham acupuncture (P>0.54). Corticomotor excitability, intracortical inhibition, and intracortical facilitation were not modulated by verum or sham acupuncture during, immediately after, or 30 min after, recorded from a local or distant hand muscle to the needling site (all P>0.075). Contrary to previous studies, manual acupuncture did not affect motor cortex excitability in healthy adults. Because of the increasing popularity of acupuncture therapy, further research using patient populations should be considered.
Prudente, CN, Zetterberg, L, Bring, A, Bradnam, L & Kimberley, TJ 2018, 'Systematic Review of Rehabilitation in Focal Dystonias: Classification and Recommendations', Movement Disorders Clinical Practice, vol. 5, no. 3, pp. 237-245.View/Download from: UTS OPUS or Publisher's site
© 2017 The Authors. Movement Disorders Clinical Practice published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society. Background: Rehabilitation interventions are rarely utilized as an alternative or adjunct therapy for focal dystonias. Reasons for limited utilization are unknown, but lack of conclusive evidence of effectiveness is likely a crucial factor. Methods and Findings: The purpose of this systematic review was to determine the level of evidence for rehabilitation interventions in focal dystonias. Rehabilitation interventions were classified based upon the underlying theoretical basis of different approaches, and the strength of evidence for each category was evaluated to identify gaps in the field. Prospective studies using rehabilitation methods in cervical, hand, and foot dystonia were reviewed. The key elements of treatments tested were identified and studies were grouped into six categories based on the theoretical basis of the intervention: (1) movement practice, (2) training with constraint, (3) sensory reorganization, (4) normalization of muscle activity with external techniques, (5) neuromodulation with training, and (6) compensatory strategies. Quality of the body of evidence ranged from very low-to-low according to the grades of recommendation, assessment, development, and evaluation (GRADE). Despite inconclusive evidence for these rehabilitation approaches, data suggest that intensive movement practice and neuromodulation combined with motor training should be further explored. Conclusions: This systematic review presents a novel approach to classify studies of rehabilitation in focal dystonias based on the theoretical basis of intervention. The proposed classification system will move toward a unified theoretical understanding of rehabilitation interventions in dystonia. Moreover, it will help provide recommendations for clinical applications and future investigations.
Barr, C, Barnard, R, Edwards, L, Lennon, S & Bradnam, L 2017, 'Impairments of balance, stepping reactions and gait in people with cervical dystonia.', Gait and Posture, vol. 55, pp. 55-61.View/Download from: UTS OPUS or Publisher's site
Impaired balance is common in neurological disorders. Cervical dystonia is a neurological movement disorder affecting the neck. The effect of this aberrant head posture on physical function is unknown.To compare balance, mobility, gait and stepping reactions between ten people with cervical dystonia and ten control adults.Spatiotemporal gait parameters and walking speed were assessed using a computerised walkway. Step length and time, time in double support and gait variability were calculated, then normalised to gait speed. Centre of pressure path length was assessed with eyes open and eyes closed to calculate a Romberg Quotient. Simple and choice reaction times were measured using customised apparatus while mobility was assessed by the timed up and go. Cervical spine range of motion was measured using a head mounted goniometer. Self-reported scales included Falls Self Efficacy Scale and Dystonia Discomfort Scale.There was a difference between groups for most outcome measures. The timed up-and-go and walking speed was slower (both P<0.005) and the Romberg Quotient lower (P=0.046) in cervical dystonia. People with cervical dystonia had lower falls self-efficacy (P=0.0002). Reduced cervical range of motion was correlated with balance, stepping reaction time and mobility (all P<0.05). Timed up and go was positively associated with stepping reaction time (P<0.01). Dystonia discomfort did not impact function.People with cervical dystonia displayed deficits in balance, gait and stepping reactions, and expressed higher fear of falling. Studies to further elucidate functional limitations and their impact on activity and participation in daily life are required.
Boyce, MJ, Lam, L, Chang, F, Mahant, N, Fung, VSC & Bradnam, L 2017, 'Validation of Fear of Falling and Balance Confidence Assessment Scales in Persons With Dystonia.', Journal of Neurologic Physical Therapy, vol. 41, no. 4, pp. 239-244.View/Download from: UTS OPUS or Publisher's site
Falls are problematic for people living with neurological disorders and a fear of falling can impact on actual falls. Fear of falling is commonly assessed using the Falls Self-Efficacy Scale International (FES-I) or the Activities-specific Balance Confidence (ABC) Scale. These scales can predict risk of falling. We aimed to validate the FES-I and the ABC in persons with dystonia.We conducted an online survey of people with dystonia, collecting information on demographics, 6-month falls history, dystonia disability, and the FES-I and ABC scales. Scales were validated for structural validity and internal consistency. We also examined goodness-of-fit, convergent validity, and predictive validity, and determined cutoff scores for predicting falls risk.Survey responses (n = 122) showed that both FES-I and ABC scales have high internal validity and convergent validity with the Functional Disability Questionnaire in persons with dystonia. Each scale examines a single factor, fear of falling (FES-I) and balance confidence (ABC). At least one fall was reported by 39% of participants; the cutoff value for falls risk was found to be 29.5 and 71.3 for the FES-I and the ABC respectively.The FES-I and the ABC scales are valid scales to examine fear of falling and balance confidence in persons with dystonia. Fear of falling is high and balance confidence is low and both are worse in those with dystonia who have previously fallen.Video Abstract available for more insights from the authors (see Video, Supplemental Digital Content 1, http://links.lww.com/JNPT/A182).
Hordacre, B, Bradnam, LV & Crotty, M 2017, 'Reorganization of the primary motor cortex following lower-limb amputation for vascular disease: a pre-post-amputation comparison.', Disability and Rehabilitation, vol. 39, no. 17, pp. 1722-1728.View/Download from: UTS OPUS or Publisher's site
PURPOSE: This study compared bilateral corticomotor and intracortical excitability of the primary motor cortex (M1), pre- and post-unilateral transtibial amputation. METHOD: Three males aged 45, 55, and 48 years respectively who were scheduled for elective amputation and thirteen (10 male, 3 female) healthy control participants aged 58.9 (SD 9.8) were recruited. Transcranial magnetic stimulation assessed corticomotor and intracortical excitability of M1 bilaterally. Neurophysiological assessments were performed 10 (SD 7) days prior to surgery and again at 10 (SD 3) days following surgery. Data were analyzed descriptively and objectively compared to 95% confidence intervals from control data. RESULTS: Prior to amputation, all three patients demonstrated stronger short-latency intracortical inhibition evoked from M1 ipsilateral to the affected limb and reduced long-latency intracortical inhibition evoked from M1 contralateral to the affected limb compared to control subjects. Following amputation, short-latency intracortical inhibition was reduced in both M1s and long-latency intracortical inhibition was reduced for the ipsilateral M1. Single-pulse motor evoked potential amplitude and motor thresholds were similar pre-to-post amputation. CONCLUSIONS: Modulation of intracortical excitability shortly following amputation indicates that the cortical environment may be optimized for reorganization in the acute post-amputation period which might be significant for learning to support prosthetic mobility. Implications for Rehabilitation Amputation of a lower-limb is associated with extensive reorganization at the level of the cortex. Reorganization occurs in the acute post-amputation period implying a favorable cortical environment for recovery. Rehabilitation or brain interventions may target the acute pre-prosthetic post-amputation period to optimize recovery.
Brackenridge, J, Bradnam, LV, Lennon, S, Costi, JJ & Hobbs, DA 2016, 'A review of rehabilitation devices to promote upper limb function following stroke', Neuroscience and Biomedical Engineering, vol. 4, no. 1, pp. 25-42.View/Download from: UTS OPUS
© 2016 Bentham Science Publishers. Background: Stroke is a major contributor to the reduced ability to carry out activities of daily living (ADL) post cerebral infarct. There has been a major focus on understanding and improving rehabilitation interventions in order to target cortical neural plasticity to support recovery of upper limb function. Conventional therapies delivered by therapists have been combined with the application of mechanical and robotic devices to provide controlled and assisted movement of the paretic upper limb. The ability to provide greater levels of intensity and reproducible repetitive task practice through the application of intervention devices are key mechanisms to support rehabilitation efficacy. Results: This review of literature published in the last decade identified 141 robotic or mechanical devices. These devices have been characterised and assessed by their individual characteristics to provide a review of current trends in rehabilitation device interventions. Correlation of factors identified to promote positive targeted neural plasticity has raised questions over the benefits of expensive robotic devices over simple mechanical ones. Conclusion: A mechanical device with appropriate functionality to support the promotion of neural plasticity after stroke may provide an effective solution for both patient recovery and to stimulate further research into the use of medical devices in stroke rehabilitation. These findings indicate that a focus on simple, cost effective and efficacious intervention solutions may improve rehabilitation outcomes.
Bradnam, L, Shanahan, EM, Hendy, K, Reed, A, Skipworth, T, Visser, A & Lennon, S 2016, 'Afferent inhibition and cortical silent periods in shoulder primary motor cortex and effect of a suprascapular nerve block in people experiencing chronic shoulder pain.', Clinical Neurophysiology, vol. 127, no. 1, pp. 769-778.View/Download from: UTS OPUS or Publisher's site
To characterise short afferent inhibition (SAI) and the cortical silent period (CSP) in the primary motor cortex representations of the infraspinatus muscle in healthy adults and people experiencing chronic shoulder pain, to determine the impact of a suprascapular nerve block (SSNB).Neurophysiological measures were obtained in 18 controls and 8 patients with chronic shoulder pain, pre and post SSNB and 1 week later. Pain intensity was assessed by a visual analogue scale.SAI was apparent in controls (all P<0.03) and a CSP was observed which reduced in the presence of SAI (all P<0.0001). Compared to controls, shoulder pain patients demonstrated higher active motor threshold (P=0.046), less SAI (P=0.044), a longer CSP (P=0.048) and less modulation of the CSP by SAI (P=0.045). Higher motor thresholds were related to higher pain scores (P=0.009). The SSNB immediately restored SAI (P=0.013), with a positive relationship between increased SAI and reduced pain (P=0.031). The SSNB further reduced modulation of CSP by SAI at 1 week post injection (P=0.006).SAI and the CSP were present and demonstrated robust interaction in controls, which was aberrant in patients. The SSNB transiently restored SAI but had no effect on the CSP; however CSP modulation by SAI was further attenuated 1 week post injection.The current findings improve understanding of the neurophysiology of the shoulder motor cortex and its modulation by chronic pain. The effect of SSNB in shoulder pain patients should be interpreted with caution until proven in a larger population. Interventions that target intracortical inhibition might increase efficacy in people with chronic shoulder pain.
Bradnam, LV, McDonnell, MN & Ridding, MC 2016, 'Cerebellar Intermittent Theta-Burst Stimulation and Motor Control Training in Individuals with Cervical Dystonia.', Brain Sci, vol. 6, no. 4.View/Download from: Publisher's site
BACKGROUND: There is emerging evidence that cervical dystonia is a neural network disorder with the cerebellum as a key node. The cerebellum may provide a target for neuromodulation as a therapeutic intervention in cervical dystonia. OBJECTIVE: This study aimed to assess effects of intermittent theta-burst stimulation of the cerebellum on dystonia symptoms, quality of life, hand motor dexterity and cortical neurophysiology using transcranial magnetic stimulation. METHODS: Sixteen participants with cervical dystonia were randomised into real or sham stimulation groups. Cerebellar neuromodulation was combined with motor training for the neck and an implicit learning task. The intervention was delivered over 10 working days. Outcome measures included dystonia severity and pain, quality of life, hand dexterity, and motor-evoked potentials and cortical silent periods recorded from upper trapezius muscles. Assessments were taken at baseline and after 5 and 10 days, with quality of life also measured 4 and 12 weeks later. RESULTS: Intermittent theta-burst stimulation improved dystonia severity (Day 5, -5.44 points; p = 0.012; Day 10, -4.6 points; p = 0.025), however, effect sizes were small. Quality of life also improved (Day 5, -10.6 points, p = 0.012; Day 10, -8.6 points, p = 0.036; Week 4, -12.5 points, p = 0.036; Week 12, -12.4 points, p = 0.025), with medium or large effect sizes. There was a reduction in time to complete the pegboard task pre to post intervention (both p < 0.008). Cortical neurophysiology was unchanged by cerebellar neuromodulation. CONCLUSION: Intermittent theta-burst stimulation of the cerebellum may improve cervical dystonia symptoms, upper limb motor control and quality of life. The mechanism likely involves promoting neuroplasticity in the cerebellum although the neurophysiology remains to be elucidated. Cerebellar neuromodulation may have potential as a novel treatment intervention for cervical dystonia, although larger confirmatory studies ...
Chothia, M, Doeltgen, S & Bradnam, LV 2016, 'Anodal Cerebellar Direct Current Stimulation Reduces Facilitation of Propriospinal Neurons in Healthy Humans', BRAIN STIMULATION, vol. 9, no. 3, pp. 364-371.View/Download from: Publisher's site
Doeltgen, SH, Young, J & Bradnam, LV 2016, 'Anodal Direct Current Stimulation of the Cerebellum Reduces Cerebellar Brain Inhibition but Does Not Influence Afferent Input from the Hand or Face in Healthy Adults.', Cerebellum (London, England).View/Download from: UTS OPUS or Publisher's site
The cerebellum controls descending motor commands by outputs to primary motor cortex (M1) and the brainstem in response to sensory feedback. The cerebellum may also modulate afferent input en route to M1 and the brainstem.The objective of this study is to determine if anodal transcranial direct current stimulation (tDCS) to the cerebellum influences cerebellar brain inhibition (CBI), short afferent inhibition (SAI) and trigeminal reflexes (TRs) in healthy adults.Data from two studies evaluating effects of cerebellar anodal and sham tDCS are presented. The first study used a twin coil transcranial magnetic stimulation (TMS) protocol to investigate CBI and combined TMS and cutaneous stimulation of the digit to assess SAI. The second study evaluated effects on trigemino-cervical and trigemino-masseter reflexes using peripheral nerve stimulation of the face.Fourteen right-handed healthy adults participated in experiment 1. CBI was observed at baseline and was reduced by anodal cerebellar DCS only (P < 0.01). There was SAI at interstimulus intervals of 25 and 30 ms at baseline (both P < 0.0001), but cerebellar tDCS had no effect. Thirteen right-handed healthy adults participated in experiment 2. Inhibitory reflexes were evoked in the ipsilateral masseter and sternocleidomastoid muscles. There was no effect of cerebellar DCS on either reflex.Anodal DCS reduced CBI but did not change SAI or TRs in healthy adults. These results require confirmation in individuals with neurological impairment.
Fletcher, C, Bradnam, L & Barr, C 2016, 'The relationship between knowledge of pain neurophysiology and fear avoidance in people with chronic pain: A point in time, observational study', PHYSIOTHERAPY THEORY AND PRACTICE, vol. 32, no. 4, pp. 271-276.View/Download from: UTS OPUS or Publisher's site
Hordacre, BG, Ridding, MC & Bradnam, LV 2016, 'The potential for non-invasive brain stimulation to improve function after amputation', Disability and Rehabilitation, vol. 38, no. 15, pp. 1521-1532.View/Download from: UTS OPUS or Publisher's site
Purpose: Lower limb amputee rehabilitation has traditionally focussed on restoration of gait and balance through use of prosthetic limbs and mobility aids. Despite these efforts, some amputees continue to experience difficulties with mastering prosthetic mobility. Emerging techniques in rehabilitation, such as non-invasive brain stimulation (NIBS), may be an appropriate tool to enhance prosthetic rehabilitation outcomes by promoting 'normal' brain reorganisation and function. The purpose of this review is to highlight the potential of NIBS to improve functional outcomes for lower limb amputees. Methods: To demonstrate the rationale for applying NIBS to amputees, this study will first review literature regarding human motor control of gait, followed by neurophysiological reorganisation of the motor system after amputation and the relationship between brain reorganisation and gait function. We will conclude by reviewing literature demonstrating application of NIBS to lower limb muscle representations and evidence supportive of subsequent functional improvements. Results: Imaging, brain stimulation and behavioural evidence indicate that the cortex contributes to locomotion in humans. Following amputation both hemispheres reorganise with evidence suggesting brain reorganisation is related to functional outcomes in amputees. Previous studies indicate that brain stimulation techniques can be used to selectively promote neuroplasticity of lower limb cortical representations with improvements in function. Conclusions: We suggest NIBS has the potential to transform lower limb amputee rehabilitation and should be further investigated.Implications for RehabilitationDespite extensive rehabilitation some amputees continue to experience difficulty with prosthetic mobilityBrain reorganisation following amputation has been related to functional outcomes and may be an appropriate target for novel interventionsNon-invasive brain stimulation is a promising tool which has potential ...
Killington, C, Barr, C, Loetscher, T & Bradnam, LV 2016, 'VARIATION IN LEFT POSTERIOR PARIETAL-MOTOR CORTEX INTERHEMISPHERIC FACILITATION FOLLOWING RIGHT PARIETAL CONTINUOUS THETA-BURST STIMULATION IN HEALTHY ADULTS', NEUROSCIENCE, vol. 330, pp. 229-235.View/Download from: UTS OPUS or Publisher's site
Bradnam, L, Williams, J & Cheary, S 2015, 'Acupuncture in stroke rehabilitation: Why is the evidence inconclusive?', INTERNATIONAL JOURNAL OF STROKE, vol. 10, pp. 56-56.
Bradnam, LV, Graetz, LJ, McDonnell, MN & Ridding, MC 2015, 'Anodal transcranial direct current stimulation to the cerebellum improves handwriting and cyclic drawing kinematics in focal hand dystonia', FRONTIERS IN HUMAN NEUROSCIENCE, vol. 9.View/Download from: UTS OPUS or Publisher's site
Doeltgen, SH, Bradnam, LV, Young, JA & Fong, E 2015, 'Transcranial non-invasive brain stimulation in swallowing rehabilitation following stroke - A review of the literature', PHYSIOLOGY & BEHAVIOR, vol. 143, pp. 1-9.View/Download from: Publisher's site
Hordacre, B, Bradnam, LV, Barr, C, Patritti, BL & Crotty, M 2015, 'Intracortical inhibition is modulated by phase of prosthetic rehabilitation in transtibial amputees', Frontiers in Human Neuroscience, vol. 9, no. MAY.View/Download from: UTS OPUS or Publisher's site
© 2015 Hordacre, Bradnam, Barr, Patritti and Crotty. Reorganization of primary motor cortex (M1) is well-described in long-term lower limb amputees. In contrast cortical reorganization during the rehabilitation period after amputation is poorly understood. Thirteen transtibial amputees and 13 gender matched control participants of similar age were recruited. Transcranial magnetic stimulation was used to assess corticomotor and intracortical excitability of M1 bilaterally. Neurophysiological assessments were conducted at admission, prosthetic casting, first walk and discharge. Gait variability at discharge was assessed as a functional measure. Compared to controls, amputees had reduced short-latency intracortical inhibition (SICI) for the ipsilateral M1 at admission (p = 0.01). Analysis across rehabilitation revealed SICI was reduced for the contralateral M1 at first walk compared to discharge (p = 0.003). For the ipsilateral M1 both short and long-latency intracortical inhibition were reduced at admission (p < 0.05) and prosthetic casting (p < 0.02). Analysis of the neurophysiology and gait function revealed several interesting relationships. For the contralateral M1, reduced inhibition at admission (p = 0.04) and first walk (p = 0.05) was associated with better gait function. For the ipsilateral M1, reduced inhibition at discharge (p = 0.05) was associated with poor gait function. This study characterized intracortical excitability in rehabilitating amputees. A dichotomous relationship between reduced intracortical inhibition for each M1 and gait function was observed at different times. Intracortical inhibition may be an appropriate cortical biomarker of gait function in lower limb amputees during rehabilitation, but requires further investigation. Understanding M1 intracortical excitability of amputees undertaking prosthetic rehabilitation provides insight into brain reorganization in the sub-acute post-amputation period and may guide future studies seeking to...
Bradnam, LV, Frasca, J & Kimberley, TJ 2014, 'Direct Current Stimulation of Primary Motor Cortex and Cerebellum and Botulinum Toxin a Injections in a Person With Cervical Dystonia', BRAIN STIMULATION, vol. 7, no. 6, pp. 909-911.View/Download from: Publisher's site
Hendy, KA, Visser, A, Hordacre, B & Bradnam, LV 2014, 'Afferent Inhibition of Infraspinatus Primary Motor Cortex by Stimulation of the Suprascapular Nerve', BRAIN STIMULATION, vol. 7, no. 2, pp. 338-339.View/Download from: Publisher's site
Hordacre, B, Bradnam, LV, Barr, C, Patritti, BL & Crotty, M 2014, 'Ipsilateral corticomotor excitability is associated with increased gait variability in unilateral transtibial amputees.', European Journal of Neuroscience, vol. 40, no. 2, pp. 2454-2462.View/Download from: UTS OPUS or Publisher's site
Ipsilateral primary motor cortex (M1) reorganisation after unilateral lower-limb amputation may degrade function of the amputated limb. We hypothesised unilateral lower-limb amputees would have a bilateral increase in corticomotor excitability, and increased excitability of ipsilateral M1 would be associated with increased step-time variability during gait. Twenty transtibial amputees (16 male) aged 60.1 years (range 45-80 years), and 20 age- and gender-matched healthy adult controls were recruited. Single-pulse transcranial magnetic stimulation assessed corticomotor excitability. Two indices of corticomotor excitability were calculated. An index of corticospinal excitability (ICE) determined relative excitability of ipsilateral and contralateral corticomotor projections to alpha-motoneurons innervating the quadriceps muscle (QM) of the amputated limb. A laterality index (LI) assessed relative excitability of contralateral projections from each hemisphere. Spatial-temporal gait analysis was performed to calculate step-time variability. Amputees had lower ICE values, indicating relatively greater excitability of ipsilateral corticomotor projections than controls (P = 0.04). A lower ICE value was associated with increased step-time variability for amputated (P = 0.04) and non-amputated limbs (P = 0.02). This association suggests corticomotor projections from ipsilateral M1 to alpha-motoneurons innervating the amputated limb QM may interfere with gait. Cortical excitability in amputees was not increased bilaterally, contrary to our hypothesis. There was no difference in excitability of contralateral M1 between amputees and controls (P = 0.10), and no difference in LI (P = 0.71). It appears both hemispheres control one QM, with predominance of contralateral corticomotor excitability in healthy adults. Following lower-limb amputation, putative ipsilateral corticomotor excitability is relatively increased in some amputees and may negatively impact on function.
Bradnam, L & Barry, C 2013, 'The Role of the Trigeminal Sensory Nuclear Complex in the Pathophysiology of Craniocervical Dystonia', JOURNAL OF NEUROSCIENCE, vol. 33, no. 47, pp. 18358-18367.View/Download from: UTS OPUS or Publisher's site
Bradnam, LV, McDonnell, MN & Ridding, MC 2013, 'Non-invasive cerebellar stimulation in focal dystonia', MOVEMENT DISORDERS, vol. 28, pp. S10-S10.
Bradnam, LV, Stinear, CM & Byblow, WD 2013, 'Ipsilateral motor pathways after stroke: implications for non-invasive brain stimulation', FRONTIERS IN HUMAN NEUROSCIENCE, vol. 7.View/Download from: UTS OPUS or Publisher's site
Hordacre, B & Bradnam, L 2013, 'Reorganisation of primary motor cortex in a transtibial amputee during rehabilitation: A case report', CLINICAL NEUROPHYSIOLOGY, vol. 124, no. 9, pp. 1919-1921.View/Download from: Publisher's site
Bradnam, LV, Stinear, CM, Barber, PA & Byblow, WD 2012, 'Contralesional Hemisphere Control of the Proximal Paretic Upper Limb following Stroke', CEREBRAL CORTEX, vol. 22, no. 11, pp. 2662-2671.View/Download from: UTS OPUS or Publisher's site
Bradnam, LV, Stinear, CM & Byblow, WD 2011, 'Cathodal transcranial direct current stimulation suppresses ipsilateral projections to presumed propriospinal neurons of the proximal upper limb', JOURNAL OF NEUROPHYSIOLOGY, vol. 105, no. 5, pp. 2582-2589.View/Download from: UTS OPUS or Publisher's site
McDowell, J, Johnson, G & Bradnam, L 2011, 'Towards a neurophysiological mechanisms based classification of adverse reactions to acupuncture', Physical Therapy Reviews, vol. 16, no. 2, pp. 118-125.View/Download from: UTS OPUS or Publisher's site
McCambridge, AB, Bradnam, LV, Stinear, CM & Byblow, WD 2011, 'Cathodal transcranial direct current stimulation of the primary motor cortex improves selective muscle activation in the ipsilateral arm', JOURNAL OF NEUROPHYSIOLOGY, vol. 105, no. 6, pp. 2937-2942.View/Download from: UTS OPUS or Publisher's site
Bradnam, LV, Stinear, CM & Byblow, WD 2010, 'Theta Burst Stimulation of Human Primary Motor Cortex Degrades Selective Muscle Activation in the Ipsilateral Arm', JOURNAL OF NEUROPHYSIOLOGY, vol. 104, no. 5, pp. 2594-2602.View/Download from: Publisher's site
Bradnam, LV, Stinear, CM, Lewis, GN & Byblow, WD 2010, 'Task-Dependent Modulation of Inputs to Proximal Upper Limb Following Transcranial Direct Current Stimulation of Primary Motor Cortex', JOURNAL OF NEUROPHYSIOLOGY, vol. 103, no. 5, pp. 2382-2389.View/Download from: Publisher's site
Bradnam, L, Stinear, CM, Lewis, GN & Byblow, WD 2008, 'Task-dependent modulation of propriospinal inputs to human shoulder', Journal of Neurophysiology, vol. 100, no. 4, pp. 2109-2114.View/Download from: Publisher's site
In the human upper limb a proportion of the descending corticospinal command may be relayed through cervical propriospinal premotoneurons. This may serve to coordinate movements involving multiple joints of the arm, such as reaching. The present study was conducted to determine whether a shoulder stabilizing muscle, infraspinatus (INF), is functionally integrated into the putative cervical propriospinal network, and whether there is task-dependent modulation of the network. Fourteen healthy adults participated in this study. Responses in the right INF were evoked by transcranial magnetic stimulation over the motor cortex and compared with responses conditioned by ulnar nerve stimulation. Interstimulus intervals were chosen to summate inputs at the level of the premotoneurons. Participants performed a forearm and shoulder muscle cocontraction task or a grip-lift task that also coactivated forearm and shoulder muscles. During the cocontraction task, INF motor-evoked potentials were significantly facilitated by ulnar nerve stimulation at low intensities and suppressed at higher intensities. Only facilitation reached significance during the grip-lift task. We have shown for the first time that propriospinal pathways may connect the hand to the rotator cuff of the shoulder. The modulation of facilitation/suppression during the grip-lift task suggests that inhibition of propriospinal premotoneurons is down-regulated in a task-dependent manner to increase the gain in the feedback reflex loop from forearm and hand muscles as required.
Chan, AK, Vujnovich, AL & Bradnam, L 2004, 'The effect of acupuncture on alpha–motoneuron excitability', Acupuncture & Electro–Therapeutics Research, vol. 29, no. 1-2, pp. 53-72.
Kerr, JM, Vujnovich, AL & Bradnam, L 2002, 'Changes in alpha-motoneuron excitability with positions that tension neural tissue.', Electromyography and clinical neurophysiology, vol. 42, no. 8, pp. 459-471.
The slump test assesses the contribution of neural tissue to the referred symptoms associated with spinal pain and musculo-skeletal injuries of the lower limb. The limitation to full range of movement in performing this test has, in the past, been attributed to a mechanical restriction in mobility of neural tissue. Recent literature suggests that the limitation may be caused by protective reflex muscle action. The purpose of this study was to establish whether the slump test was associated with an increase or a decrease in excitability of alpha-motoneurons and, therefore, an alteration in muscle activity at the end of the range of movement of the test. Forty-three normal subjects and eight subjects with abnormal neural tension participated in this study. Changes in alpha-motoneuron excitability in neck flexion, moderate slump, and maximum slump positions were assessed by observing changes in H-reflex recruitment curves. Linear regression analysis on the rising portion of the H-reflex recruitment curve enabled calculation of the dependent variable Hslp for statistical analysis. Normal subjects in the moderate and maximum slump positions demonstrated a significant decrease (p < 0.05) in the slope of the H-reflex recruitment curve. Subjects with abnormal neural tension showed a non-significant increase in slope when in these positions. Subject flexibility had a significant influence on motoneuron excitability in the moderate neural tension position with inflexible subjects demonstrating a significant inhibition of motoneurons. The difference between the flexible or moderately flexible subjects and inflexible subjects was not significant in the maximum neural tension position. These findings have important implications for the rationale for treatment selection and success of treatment outcomes in the clinical setting.
Kerr, JM, Vujnovich, AL & Bradnam, L 2002, 'The intercept method: A novel method for establishing consistency of M-wave recruitment curves', Electromyography and Clinical Neurophysiology, vol. 42, no. 7, pp. 423-432.
The stability of the M-wave is an important component of experimental H-reflex methodology. Despite this importance, there is inconsistency in H-reflex literature on the most valid method of M-wave stability analysis. Further, there is currently no specific method for establishing the stability of an M-wave recruitment curve across various trials within an experiment. Therefore, the aim of this study was to investigate the most appropriate method of M-wave stability analysis for use with the recruitment curve methodology. Twenty-five healthy subjects participated in the study. Four M-wave recruitment curve recordings were made in various static positions that imposed stretch on the posterior structures of the back and leg. Four methods of post-data collection M-wave stability analysis were compared. Although on visual inspection, there was clear evidence of marked alterations to the M-wave recruitment curves between trials in some subject's data, analysis of variance of the Mslp and Mmax found no significant difference. Evaluation of the percent deviation in Mmax found nine subjects with greater than ten percent deviation in their maximum M-wave across the four trials. The intercept method that utilises analysis of the 95% confidence interval of the intercept of the M-wave recruitment curve slope, excluded eight subjects that demonstrated variation. Comparison of the percent deviation and the intercept method revealed that the intercept method was the most appropriate method for M-wave stability analysis in conjunction with the recruitment curve methodology.
Bradnam, L, Rochester, L & Vujnovich, A 2000, 'Manual cervical traction reduces alpha-motoneuron excitability in normal subjects.', Electromyography and clinical neurophysiology, vol. 40, no. 5, pp. 259-266.
The excitability of the Flexor Carpi Radialis alpha-motoneuron pool following manual cervical traction was assessed in twenty asymptomatic subjects, and compared to a hands only intervention. The excitability of the alpha-motoneuron pool was measured indirectly using the Hoffmann (H) reflex. H-reflex recruitment curves were taken to assess the number of alpha-motoneurons (alpha-motoneurons) firing in response to a given incremental increase in stimulation intensity. The rate of rise of the slope of the H-reflex recruitment curve (Hslp) was assessed using linear regression. Following manual cervical traction Hslp was significantly lower than pre-intervention trials. Manual cervical traction, therefore, reduced the excitability of the Flexor Carpi Radialis alpha-motoneuron pool. This effect was mediated by the central nervous system. There was no significant decrease in alpha-motoneuron excitability following the hands only intervention. Hslp was shown to be a more sensitive measure of changes in the H-reflex than the more traditional parameter of Hmax/Mmax ratio and should be used in future studies of this nature.
Katavich, L 1999, 'Neural mechanisms underlying manual cervical traction', Journal of Manual and Manipulative Therapy, vol. 7, no. 1, pp. 20-25.View/Download from: Publisher's site
Manual therapy is commonly used to decrease pain and improve function of the musculoskeletal system in spite of scant knowledge of the underlying mechanisms. Manual cervical traction is suggested to relieve pain and muscle spasm in the neck and upper quartile. Afferent input generated by these procedures may lower the excitability of α-motoneuron pools of upper limb muscles. While joint receptors are traditionally viewed as the receptor most likely to evoke responses to manual therapy, a review of the literature into possible mechanisms underlying manual cervical traction suggests stretch generated in cervical muscles and skin during the procedure has the potential to influence the excitability of α-motoneurons. An understanding of the receptors and mechanisms underlying manual therapy may allow more effective stimulation, and hence, improved clinical outcomes.
Katavich, L 1998, 'Differential effects of spinal manipulative therapy on acute and chronic muscle spasm: A proposal for mechanisms and efficacy', Manual Therapy, vol. 3, no. 3, pp. 132-139.View/Download from: Publisher's site
Spinal manipulative therapy (SMT) has evolved as an area of specialization within the physiotherapy profession, providing assessment and treatment of musculoskeletal disorders. Despite widespread acceptance and clinical use, the efficacy and mechanisms underlying the effects of SMT remain largely unknown. While research has demonstrated positive treatment outcomes for SMT in acute, nocioceptive pain, no such benefit has been shown for chronic pain. Plasticity of the central nervous system (CNS) in response to acute inflammation is known to increase the excitability of the alpha motoneuron pool, producing reflexly mediated aberrations of movement. This may in turn create afferent input sufficient to maintain central sensitization in the chronic situation. Sensory input produced with SMT may stimulate neurophysiological pathways to inhibit pain and muscle responses in acute nocioceptive pain. These mechanisms may not prove efficacious in chronic conditions due to fundamental differences in the underlying physiology of the pain. Therapeutic movement aimed at normalizing central neuronal functioning in chronic conditions may be an alternative treatment intervention.
McCambridge, A & Bradnam, L 2018, 'S63. Cerebellar stimulation for adults with cervical dystonia: A tDCS study', International Congress of Clinical Neurophysiology, Washington, pp. 165-165.View/Download from: UTS OPUS or Publisher's site
Cervical dystonia (CD) is characterized by painful, involuntary twisting of the neck, and sometimes tremor. Unfortunately, treatment options for CD are limited and the underlying pathophysiology is not well understood. Recent evidence implicates cerebellar dysfunction may play a role in the development of CD symptoms. Non-invasive brain stimulation is able to modulate neural excitability of the cerebellum.
The present study examined the effect of five consecutive days of anodal transcranial direct current stimulation (tDCS) over the cerebellum of adults with CD (2 mA, 20 min). Patients received five sessions of anodal tDCS and sham tDCS in a randomised, cross-over design that was double-blinded. During tDCS, patients performed a motor imagery task (first 10 min) and a real movement task (last 10 min). We hypothesised that anodal tDCS would improve patient's clinical features and modulate neural excitability of the cerebellum. Clinical features were examined using the TWSTRS2, CDQ-24, cervical range of motion, and visual analogue scales of pain. Behavioural outcomes were assessed using a motor learning finger tracking task. Neural excitability was inferred using eye-blink conditioning to examine cerebellar excitability and single-pulse transcranial magnetic stimulation (TMS) over the motor cortex to examine corticomotor excitability and intracortical inhibition. Motor evoked potentials (MEP) and cortical silent periods (cSP) were recorded bilaterally from the upper trapezius (UT) and first dorsal interosseous (FDI) muscles. All dependent measures were assessed on day-1 and day-5 of the intervention, and follow up questionnaires were completed one and four weeks later. There was a minimum washout period of 5 weeks between treatment blocks, and patients undergoing Botox were tested 4 weeks post injections.
The study is in the late stages of data collection and analysis (n = 14 patients enrolled, 8 males).
The outcome of thi...
Bradnam, L, Ridding, M & McDonnell, M 2013, 'Non-invasive cerebellar stimulation for treatment of focal dystonia', JOURNAL OF NEURAL TRANSMISSION, pp. 1139-1139.
Associate Professor Teresa Jacobson Kimberley. University of Minnesota, USA