Dr Michael Lee is a Senior Lecturer and the Head of Musculoskeletal Physiotherapy in the Graduate School of Health. Dr Lee is a registered Physiotherapist and Chiropractor in Australia and an experienced clinician and educator. He has held academic appointments at the University of Sydney (Faculty of Health Sciences, Discipline of Physiotherapy), Macquarie University (Department of Chiropractic) and the University of New South Wales (School of Medical Sciences, Exercise Physiology) before joining UTS in September 2016.
Dr Lee has a PhD in Medicine (Neuroscience) obtained from the University of New South Wales and completed his post-doctoral training in Clinical Neurology with Professor Matthew Kiernan at the Brain and Mind Centre. Michael was awarded a prestigious Applied Spinal Cord Injury Research Fellowship (2011-2014) from the New South Wales Office for Medical Research and his post-doctoral studies have demonstrated that an intensive, short-term program of functional electrical stimulation improved peripheral nerve function in patients with traumatic spinal cord injury.
Michael’s area of research is clinical neurology. He is particularly fascinated by diseases of the human brain that occur as a consequence of neurodegeneration. Michael’s current research focuses on understanding the pathophysiological processes underlying motor neuron degeneration in amyotrophic lateral sclerosis (ALS). He utilises novel transcranial magnetic stimulation (TMS) and neuroimaging techniques (magnetoencephalography, MEG) with the goal of identifying potential clinical biomarker of disease activity and progression for ALS. Biomarkers can help to detect the earliest changes in the disease, allowing for early intervention and clinical trial of new therapies before the disease spreads. Michael also conducts clinical studies to better understand the central mechanisms mediating fatigue in ALS patients and has instigated studies which specifically elucidate the neuroprotective benefits of exercise in this clinical population.
Michael also conducts clinical studies to better understand the natural history of diabetic neuropathy and effectiveness of non-invasive brain stimulation as a treatment for chronic pain.
CLINICAL NEUROPHYSIOLOGIST, ForeFront Multidisciplinary Motor Neuron Disease Clinic, The Brain & Mind Center, University of Sydney
RESEARCH AFFILATE, Neuroscience Research Australia and the Prince of Wales Hospital (Pain Management Unit)
VISITING RESEARCH ACADEMIC, Department of Cognitive Science, Macquarie University
APPLIED SPINAL CORD INJURY RESEARCH FELLOW, NSW Office for Medical Research
Can supervise: YES
Clinical Neurology, Motor Neurone Disease, Amyotrophic Lateral Sclerosis, Spinal Cord Injury, Chronic Pain, Transcranial Magnetic Stimulation (TMS), Peripheral Neuropathy
Michael is the Head of Musculoskeletal Physiotherapy.
Lee, M & McCambridge, A 2018, 'Clinimetrics: Amyotrophic Lateral Sclerosis Functional Rating Scale-revised (ALSFRS-R)', Journal of Physiotherapy, vol. 64, no. 4, pp. 269-270.View/Download from: Publisher's site
Adams, J, Lee, M & Peng, W 2018, 'Critical Review of Complementary and Alternative Medicine Use in Amyotrophic Lateral Sclerosis: Prevalence and Users' Profile, Decision-Making, Information Seeking, and Disclosure in the Face of a Lack of Efficacy', NEURODEGENERATIVE DISEASES, vol. 18, no. 4, pp. 225-232.View/Download from: UTS OPUS or Publisher's site
Lee, M, Luz-Santos, C, Camatti, J, Paixao, AB, Nunes Sa', K, Montoya, P & Baptista, A 2017, 'Additive effect of tDCS combined with peripheral electrical stimulation to an exercise program in pain control in knee osteoarthritis: Study protocol for a randomized controlled trial', Trials, vol. 18, no. 609, pp. 1-11.View/Download from: UTS OPUS or Publisher's site
Background: Knee osteoarthritis (OA) has been linked to maladaptive plasticity in the brain, which may contribute
to chronic pain. Neuromodulatory approaches, such as Transcranial Direct Current Stimulation (tDCS) and Peripheral
Electrical Stimulation (PES), have been used therapeutically to counteract brain maladaptive plasticity. However, it is
currently unclear whether these neuromodulatory techniques enhance the benefits of exercise when administered
together. Therefore, this protocol aims to investigate whether the addition of tDCS combined or not with PES
enhances the effects of a land-based strengthening exercise program in patients with knee OA.
Methods: Patients with knee OA (n = 80) will undertake a structured exercise program for five consecutive days.
In addition, they will be randomized into four subgroups receiving either active anodal tDCS and sham PES (group
1; n = 20), sham tDCS and active PES (group 2, n = 20), sham tDCS and PES (group 3, n = 20), or active tDCS and
PES (group 4, n = 20) for 20 min/day for five consecutive days just prior to commencement of the exercise program.
The primary outcomes will be subjective pain intensity (VAS) and related function (WOMAC). Secondary outcomes will
include quality of life (SF-36), anxiety and depression symptoms (HAD), self-perception of improvement, pressure pain
thresholds over the knee, quadriceps strength, and quadriceps electromyographic activity during maximum knee
extension voluntary contraction. We will also investigate cortical excitability using transcranial magnetic stimulation.
Outcome measures will be assessed at baseline, 1 month after, before any intervention, after 5 days of intervention,
and at 1 month post exercise intervention.
Discussion: The motor cortex becomes less responsive in knee OA because of poorly adapted plastic changes, which
can impede exercise therapy benefits. Adding tDCS and/or PES may help to counteract those maladaptive plastic
changes and improve the benefits of e...
Lee, M, Meng, D, Kiernan, MC & Johnson, BW 2016, 'Exploring motor imagery and motor cortical function in ALS using magnetoencephalography', Clinical Neurophysiology, vol. 127, no. 3, pp. e12-e12.View/Download from: Publisher's site
Simon, NG, Lee, M, Bae, JS, Mioshi, E, Lin, CS-Y, Pfluger, CM, Henderson, RD, Vucic, S, Swash, M, Burke, D & Kiernan, MC 2015, 'Dissociated lower limb muscle involvement in amyotrophic lateral sclerosis.', J Neurol, vol. 262, no. 6, pp. 1424-1432.View/Download from: UTS OPUS or Publisher's site
It has been suggested that corticomotoneuronal drive to ankle dorsiflexors is greater than to ankle plantar flexor muscles, despite the finding that plantar flexors are no less active than TA during walking and standing. The present study was undertaken to determine whether there was differential involvement of distal lower limb muscles in amyotrophic lateral sclerosis (ALS), to elucidate pathophysiological mechanisms of selective muscle involvement. Prospective studies were undertaken in 52 ALS patients, including clinical assessment, disease staging (revised ALS functional rating scale), Medical Research Council sum score, and a scale of upper motor neurone (UMN) dysfunction. Motor unit number estimates (MUNE) and compound muscle action potentials (CMAP) from ankle dorsiflexors and plantar flexors were used to provide objective measures. A novel 'split leg index' was calculated as follows: SLI = CMAPDF ÷ CMAPPF. In ALS, there was significantly greater reduction of MUNE and CMAP amplitude recorded from plantar flexors when compared to dorsiflexors, suggesting preferential involvement of plantar flexor muscles, underpinning a 'split leg' appearance. The SLI correlated with clinical plantar flexor strength (R= -0.56, p < 0.001). In no patient did the SLI suggest preferential dorsiflexor involvement. In subgroup analyses, mean SLI was greatest in lower limb-onset ALS. In conclusion, the present study has established dissociated involvement of muscles acting around the ankle in ALS. We suggest this reflects underlying differences in cortical, descending or local spinal modulation of these muscles.
Simon, NG, Lin, CS-Y, Lee, M, Howells, J, Vucic, S, Burke, D & Kiernan, MC 2015, 'Segmental motoneuronal dysfunction is a feature of amyotrophic lateral sclerosis.', Clinical Neurophysiology, vol. 126, no. 4, pp. 828-836.View/Download from: UTS OPUS or Publisher's site
OBJECTIVES: There is accumulating evidence of dysfunction of spinal circuits in the pathogenesis of amyotrophic lateral sclerosis (ALS). METHODS: The present study was undertaken to characterise the pathophysiological changes in segmental motoneuronal excitability in 28 ALS patients, using recruitment curves of the soleus H-reflex and M-wave, compared with clinical assessments of upper motor neuron (UMN) and lower motor neuron dysfunction. RESULTS: H-reflex recruitment curves established that Hmax/Mmax and slope (Hθ/Mθ) ratios predicted clinical UMN dysfunction (p<0.001). Changes in Hθ/Mθ were driven by reduced Mθ. Assessment of Hmax/Mmax was similar in the ALS and control groups, and was affected by overlap of the H and M recruitment curves in ALS patients. CONCLUSION: Changes in the slope ratio (Hθ/Mθ) in ALS suggested that alterations in peripheral motor nerve excitability following UMN damage may affect the recorded H-reflex. Increased collision of reflex discharges with antidromically-conducted motor impulses may be exacerbated in ALS due to preferential loss of large-caliber α-motoneurones, which may explain the similarities in Hmax/Mmax between groups. SIGNIFICANCE: Findings from the present study provide further insight into the pathophysiology of ALS, specifically the relative contributions of premotoneuronal and segmental motoneuronal dysfunction.
Lee, M, Kiernan, MC, Macefield, VG, Lee, BB & Lin, CS-Y 2015, 'Short-term peripheral nerve stimulation ameliorates axonal dysfunction after spinal cord injury', JOURNAL OF NEUROPHYSIOLOGY, vol. 113, no. 9, pp. 3209-3218.View/Download from: UTS OPUS or Publisher's site
Pickering, H, Lee, M, Moseley, GL, Minei, P & Lin, CY 2012, 'Sensory disturbances evoked by immobilization of an experimentally inflamed limb', Clinical Neurophysiology, vol. 137, no. 7, pp. e71-e72.View/Download from: Publisher's site
Lee, M, Hinder, MR, Gandevia, SC & Carroll, TJ 2010, 'The ipsilateral motor cortex contributes to cross-limb transfer of performance gains after ballistic motor practice', Journal of Physiology, vol. 588, no. 1, pp. 201-212.View/Download from: Publisher's site
Although it has long been known that practicing a motor task with one limb can improve performance with the limb opposite, the mechanisms remain poorly understood. Here we tested the hypothesis that improved performance with the untrained limb on a fastest possible (i.e. ballistic) movement task depends partly on cortical circuits located ipsilateral to the trained limb. The idea that crossed effects, which are important for the learning process, might occur in the 'untrained' hemisphere following ballistic training is based on the observation that tasks requiring strong descending drive generate extensive bilateral cortical activity. Twenty-one volunteers practiced a ballistic index finger abduction task with their right hand, and corticospinal excitability was assessed in two hand muscles (first dorsal interosseus, FDI; adductor digiti minimi, ADM). Eight control subjects did not train. After training, repetitive transcranial magnetic stimulation (rTMS; 15 min at 1 Hz) was applied to the left (trained) or right (untrained) motor cortex to induce a 'virtual lesion'. A third training group received sham rTMS, and control subjects received rTMS to the right motor cortex. Performance and corticospinal excitability (for FDI) increased in both hands for training but not control subjects. rTMS of the left, trained motor cortex specifically reduced training-induced gains in motor performance for the right, trained hand, and rTMS of the right, untrained motor cortex specifically reduced performance gains for the left, untrained hand. Thus, cortical processes within the untrained hemisphere, ipsilateral to the trained hand, contribute to early retention of ballistic performance gains for the untrained limb. © 2010 The Authors. Journal compilation © 2010 The Physiological Society.
Lee, M, Gandevia, SC & Carroll, TJ 2009, 'Short-term strength training does not change cortical voluntary activation.', Medicine and science in sports and exercise, vol. 41, no. 7, pp. 1452-1460.View/Download from: Publisher's site
PURPOSE: The neural mechanisms responsible for strength improvement in the early phase of strength training are unknown. One hypothesis is that strength increases because of increased neural drive to the trained muscles. Here, we used twitch interpolation to assess voluntary activation before and after a 4-wk strength training program. METHODS: Twelve volunteers performed unilateral strength training for the right wrist abductors (three times per week). Control subjects (n = 11) practiced the same movement without resistance. We assessed voluntary activation of the trained muscles during wrist abduction and extension contractions using twitch interpolation with motor nerve and motor cortical stimulation. RESULTS: Strength training increased wrist abduction maximal voluntary contraction (MVC) force for the trained hand by 11.0% (+/-8.7, P < 0.01). MVC of the untrained wrist was unchanged. There were no significant changes in wrist extension MVC force in either group. During submaximal wrist abduction, but not extension contractions, the average size of the superimposed twitches produced by cortical stimulation was significantly larger after strength training (P < 0.01). Furthermore, the direction of the twitches produced by cortical stimulation during wrist abductions and maximal wrist extension shifted toward abduction (P = 0.04). There were neither significant changes in voluntary activation measured during MVC with motor nerve or motor cortical stimulation nor changes in the amplitude of evoked EMG responses to motor cortical or motor nerve stimulation. CONCLUSIONS: Four weeks of strength training produced a small increase in MVC that was specific to the training direction. Although maximal voluntary activation did not change with short-term strength training, the changes in direction and amplitude of cortically evoked twitches suggest that motor cortical stimulation (and presumably volition) can generate motor output more effectively to the trained muscles.
Carroll, TJ, Barton, J, Hsu, M & Lee, M 2009, 'The effect of strength training on the force of twitches evoked by corticospinal stimulation in humans', Acta Physiologica, vol. 197, no. 2, pp. 161-173.View/Download from: Publisher's site
Aim: Although there is considerable evidence that strength training causes adaptations in the central nervous system, many details remain unclear. Here we studied neuromuscular responses to strength training of the wrist by recording electromyographic and twitch responses to transcranial magnetic stimulation (TMS) and cervicomedullary stimulation of the corticospinal tract. Methods: Seventeen participants performed 4 weeks (12 sessions) of strength training for the radial deviator (RD) muscles of the wrist (n = 8) or control training without external load (n = 9). TMS recruitment curves were constructed from stimuli at five to eight intensities ranging between 15% below resting motor threshold and maximal stimulator output, both at rest and during isometric wrist extension (EXT) and RD at 10% and 50% of maximal voluntary contraction (MVC). Responses to weak TMS and cervicomedullary stimulation (set to produce a response of 10% maximal M wave amplitude during 10% MVC EXT contraction) were also compared at contraction strengths ranging from 10% to 75% MVC. Results: Isometric strength increased following strength training (10.7% for the RD MVC, 8.8% for the EXT MVC), but not control training. Strength training also significantly increased the amplitude of TMS- and cervicomedullary-evoked twitches during low-force contractions. Increases in the force-generating capacity of the wrist extensor muscles are unlikely to account for this finding because training did not affect the amplitude of twitches elicited by supra-maximal nerve stimulation. Conclusion: The data suggest that strength training induces adaptations that increase the net gain of corticospinal-motor neuronal projections to the trained muscles. © 2009 Scandinavian Physiological Society.
Lee, M, Gandevia, SC & Carroll, TJ 2009, 'Unilateral strength training increases voluntary activation of the opposite untrained limb', Clinical Neurophysiology, vol. 120, no. 4, pp. 802-808.View/Download from: Publisher's site
Objective: We investigated whether an increase in neural drive from the motor cortex contributes to the cross-limb transfer of strength that can occur after unilateral strength training. Methods: Twitch interpolation was performed with transcranial magnetic stimulation to assess changes in strength and cortical voluntary activation in the untrained left wrist, before and after 4 weeks of unilateral strength-training involving maximal voluntary isometric wrist extension contractions (MVCs) for the right wrist (n = 10, control group = 10). Results: Wrist extension MVC force increased in both the trained (31.5 ± 18%, mean ± SD, p < 0.001) and untrained wrist (8.2 ± 9.7%, p = 0.02), whereas wrist abduction MVC did not change significantly. The amplitude of the superimposed twitches evoked during extension MVCs decreased by 35% (±20%, p < 0.01), which contributed to a significant increase in voluntary activation (2.9 ± 3.5%, p < 0.01). Electromyographic responses to cortical and peripheral stimulation were unchanged by training. There were no significant changes for the control group which did not train. Conclusion: Unilateral strength training increased the capacity of the motor cortex to drive the homogolous untrained muscles. Significance: The data show for the first time that an increase in cortical drive contributes to the contralateral strength training effect. © 2009 International Federation of Clinical Neurophysiology.
Carroll, TJ, Lee, M, Hsu, M & Sayde, J 2008, 'Unilateral practice of a ballistic movement causes bilateral increases in performance and corticospinal excitability', Journal of Applied Physiology, vol. 104, no. 6, pp. 1656-1664.View/Download from: Publisher's site
It has long been known that practicing a task with one limb can result in performance improvements with the opposite, untrained limb. Hypotheses to account for cross-limb transfer of performance state that the effect is mediated either by neural adaptations in higher order control centers that are accessible to both limbs, or that there is a "spillover" of neural drive to the opposite hemisphere that results in bilateral adaptation. Here we address these hypotheses by assessing performance and corticospinal excitability in both hands after unilateral practice of a ballistic finger movement. Participants (n = 9) completed 300 practice trials of a ballistic task with the right hand, the aim of which was to maximize the peak abduction acceleration of the index finger. Practice caused a 140% improvement in right-hand performance and an 82% improvement for the untrained left hand. There were bilateral increases in the amplitude of responses to transcranial magnetic stimulation, but increased corticospinal excitability was not correlated with improved performance. There were no significant changes in corticospinal excitability or task performance for a control group that did not train (n = 9), indicating that performance testing for the left hand alone did not induce performance or corticospinal effects. Although the data do not provide conclusive evidence whether increased corticospinal excitability in the untrained hand is causally related to the cross-transfer of ballistic performance, the finding that ballistic practice can induce bilateral corticospinal adaptations may have important clinical implications for movement rehabilitation. Copyright © 2008 the American Physiological Society.
Lee, M, Gandevia, SC & Carroll, TJ 2008, 'Cortical voluntary activation can be reliably measured in human wrist extensors using transcranial magnetic stimulation', Clinical Neurophysiology, vol. 119, no. 5, pp. 1130-1138.View/Download from: Publisher's site
Objective: A twitch interpolation technique using transcranial magnetic stimulation (TMS) was recently developed to measure motor cortical drive to human elbow flexors. Here, we described studies designed to test the applicability and reliability of the technique for the human wrist extensors and to provide new evidence regarding the sensitivity of the technique to inadvertent antagonist activation. Methods: Study 1: we measured amplitudes of superimposed twitches (SITs) produced by TMS during wrist extension at intensities from rest to maximal voluntary contraction on two occasions (n = 9). Study 2: we assessed the impact of inadvertent antagonist activation by TMS on measurement of voluntary activation using a muscle potentiation technique to increase mechanical efficiency of the wrist flexors (n = 6). Results: The SITs decreased linearly between 25% and 100% MVC and voluntary activation could be reliably estimated across days (ICC2,1 = 0.963, p < 0.001). Prior potentiation of the wrist flexors had little impact on extension SITs and voluntary activation. Conclusions: TMS allows valid and reliable measurement of voluntary activation of the wrist extensors. Significance: TMS can be used to assess effects of supraspinal fatigue, pathology and rehabilitation interventions on cortical activation in upper limb muscle groups. © 2008 International Federation of Clinical Neurophysiology.
Lee, M & Carroll, TJ 2007, 'Cross education: Possible mechanisms for the contralateral effects of unilateral resistance training', Sports Medicine, vol. 37, no. 1, pp. 1-14.View/Download from: Publisher's site
Resistance training can be defined as the act of repeated voluntary muscle contractions against a resistance greater than those normally encountered in activities of daily living. Training of this kind is known to increase strength via adaptations in both the muscular and nervous systems. While the physiology of muscular adaptations following resistance training is well understood, the nature of neural adaptations is less clear. One piece of indirect evidence to indicate that neural adaptations accompany resistance training comes from the phenomenon of 'cross education', which describes the strength gain in the opposite, untrained limb following unilateral resistance training. Since its discovery in 1894, subsequent studies have confirmed the existence of cross education in contexts involving voluntary, imagined and electrically stimulated contractions. The cross-education effect is specific to the contralateral homologous muscle but not restricted to particular muscle groups, ages or genders. A recent meta-analysis determined that the magnitude of cross education is ≈7.8% of the initial strength of the untrained limb. While many features of cross education have been established, the underlying mechanisms are unknown. This article provides an overview of cross education and presents plausible hypotheses for its mechanisms. Two hypotheses are outlined that represent the most viable explanations for cross education. These hypotheses are distinct but not necessarily mutually exclusive. They are derived from evidence that high-force, unilateral, voluntary contractions can have an acute and potent effect on the efficacy of neural elements controlling the opposite limb. It is possible that with training, long-lasting adaptations may be induced in neural circuits mediating these crossed effects. The first hypothesis suggests that unilateral resistance training may activate neural circuits that chronically modify the efficacy of motor pathways that project to the opposit...
Carroll, TJ, Herbert, RD, Munn, J, Lee, M & Gandevia, SC 2006, 'Contralateral effects of unilateral strength training: Evidence and possible mechanisms', Journal of Applied Physiology, vol. 101, no. 5, pp. 1514-1522.View/Download from: Publisher's site
If exercises are performed to increase muscle strength on one side of the body, voluntary strength can increase on the contralateral side. This effect, termed the contralateral strength training effect, is usually measured in homologous muscles. Although known for over a century, most studies have not been designed well enough to show a definitive transfer of strength that could not be explained by factors such as familiarity with the testing. However, an updated meta-analysis of 16 properly controlled studies (range 15-48 training sessions) shows that the size of the contralateral strength training effect is ∼8% of initial strength or about half the increase in strength of the trained side. This estimate is similar to results of a large, randomized controlled study of training for the elbow flexors (contralateral effect of 7% initial strength or one-quarter of the effect on the trained side). This is likely to reflect increased motoneuron output rather than muscular adaptations, although most methods are insufficiently sensitive to detect small muscle contributions. Two classes of central mechanism are identified. One involves a "spillover" to the control system for the contralateral limb, and the other involves adaptations in the control system for the trained limb that can be accessed by the untrained limb. Cortical, subcortical and spinal levels are all likely to be involved in the "transfer," and none can be excluded with current data. Although the size of the effect is small and may not be clinically significant, study of the phenomenon provides insight into neural mechanisms associated with exercise and training. Copyright © 2006 the American Physiological Society.
Lee, M & Carroll, TJ 2005, 'The amplitude of Mmax in human wrist flexors varies during different muscle contractions despite constant posture', Journal of Neuroscience Methods, vol. 149, pp. 95-100.
The amplitude of the maximal direct motor response (Mmax) elicited by supramaximal peripheral nerve stimulation can vary with time
and with changes in muscle length.We sought to investigate the variability in the amplitude of Mmax in the human wrist flexors (flexor carpi
radialis, FCR) at a constant joint position during different functional tasks. The subjects performed isometric wrist extension, radial deviation
and gripping contractions matching either 10% or 50% of the EMG activity recorded in the extensor carpi radialis brevis (ECRB) during
a wrist extension maximal voluntary contraction (MVC). Three supramaximal stimuli were delivered to the median nerve near the elbow
during each task with 2–3 s between stimuli. Considerable variation was observed in the Mmax amplitude between the six tasks for individual
subjects (coefficient of variation (CV) range, 6.0–31.4%). There was significantly greater variability between tasks at 50% MVC than at
10% MVC (p = 0.017). However, there were no systematic differences in Mmax amplitude between the six tasks across the group (p > 0.05).
These results suggest that the amplitude of Mmax cannot be assumed as constant during experiments involving voluntary contractions even
when subjects maintain the same posture.
Lee, M, Huynh, W & Kiernan, MC 2015, 'Rehabilitation of gait and balance after CNS damage' in Ward, N & Dietz, V (eds), Oxford Textbook of Neurorehabilitation, Oxford University Press, UK, pp. 224-237.