Research participant's arm in a machine designed for motor impairment study

Motor Impairment

RESEARCH CENTRE

Program focus

The NHMRC-funded Motor Impairment Program will answer key questions about the neurophysiology, neuropathophysiology and clinical management of motor impairment.

Our research has three main themes, corresponding to three types of motor impairment that are important causes of physical disability [1,2] and commonly occur together:

1. Weakness and fatigue
2. Impaired sensation and balance
3. Contracture

For each theme (see Figure) we have identified (a) critical gaps in current understanding; (b) key questions which can be answered by emerging research techniques; and (c) promising new directions for therapeutic intervention.

Our vision is to advance the transfer of new understanding of physiology and pathophysiology in motor impairment toward the clinical outcome of improved motor function.

Our research approaches
We will conduct our studies on human volunteers and patients using a range of overlapping research approaches, from pure basic (physiological) research to applied (clinical) research. This combination of approaches will ensure that our clinical research is informed by contemporary understanding of the mechanisms of motor impairment. We will nest laboratory studies within larger clinical studies to explore the mechanisms underlying effects observed in clinical trials.

Within this spectrum of research approaches, our studies will focus on:

  • understanding normal function;
  • understanding mechanisms of motor impairment by testing people with impairment;
  • understanding mechanisms of interventions, either in healthy or impaired populations; and
  • testing clinical effects of interventions.

Many of the planned studies will examine neurophysiology and pathoneurophysiology of the motor system, namely the structures and processes which produce and control body movement.

This will involve studying the command to muscles provided by the brain, as well as the muscles that effect those commands. We will also investigate the processing of sensory information used to plan and provide ongoing control of movement.

Here are some examples of work that will take place in each of the themes:

Theme 1: Weakness and fatigue
Through randomised controlled trials, we will investigate which interventions are effective in improving movement function in multiple sclerosis, and the mechanisms underlying the changes (for example, in the ‘iFIMS Trial: Preventing Falls in People With Multiple Sclerosis’).

We will conduct laboratory studies to address the following:

  • how can we use different forms of neural stimulation to overcome weakness;
  • what does the spinal cord play in neuroplasticity;
  • what are some of the real-world effects of muscle fatigue on balance in the elderly; and
  • what are the mechanisms that contribute to ‘central’ fatigue.

Theme 2: Impaired sensation and balance
Through randomised controlled trials, we will investigate which multifactorial interventions are most effective in preventing falls in older people and the mechanisms underlying their effectiveness (for example, in the ‘iMAP Trial: Preventing Falls in Older People’).

We will conduct laboratory studies to assess the following:

the neural mechanisms underlying proprioception and the sensation of body ownership;
sensory mechanisms in stepping responses; and
the role of joint pain in sensorimotor disturbances in arthritis.
Theme 3: Contracture
We will trial novel approaches to the measurement and potentially the treatment of muscle contracture. Our laboratory studies will include studies of the ‘passive’ 3D recruitment of muscle fascicles and the properties of tendons in vivo. This work will lead to studies in clinical populations in whom contracture is common, such as people with stroke, spinal cord injury and multiple sclerosis. Our studies will also focus on understanding hand function and the changes in muscle and tendon behaviour following stroke.

References
1: Ada L and Canning C. Key Issues in Neurological Physiotherapy Oxford: Butterworth Heinemann, 1990, p. xv, 295 p.

2: McConnell J and Crosbie J. Key Issues in Musculoskeletal Physiotherapy. Oxford; Boston: Butterworth Heinemann, 1993, p. xv, 204 p.

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Brain and Knee Muscle Weakness Study

Why Does Quadriceps Weakness Persist after Total Knee Replacement? An Exploration of Neurophysiological Mechanisms Total knee replacement is a commonly performed surgery for treating end-staged knee osteoarthritis. Although most people recover well after surgery, weakness of the quadriceps muscles (the front thigh muscles) persists long after the surgery (at least for 12 months), despite intensive physiotherapy and exercise. Quadriceps muscle weakness is known to be associated with more severe pain and greatly affect daily activities. This study aims to investigate the mechanisms underlying weakness of the quadriceps muscles in people with knee osteoarthritis and total knee replacement. We hope to better understand the relationship between the changes of the brain and a loss of quadriceps muscle strength after total knee replacement. The study might be a good fit for you if you: Scheduled to undergo a total knee replacement; The surgery is scheduled within the next 4 weeks; Do not have a previous knee joint replacement in the same knee; Do not have high tibial osteotomy; Do not have neurological disorders, epilepsy, psychiatric conditions, other chronic pain conditions; Do not have metal implants in the skull; Do not have a loss of sensation in the limbs. If you decide to take part you would: Be contacted by the researcher to determine your eligibility for the study Be scheduled for testing if you are eligible and willing to take part in the study Sign the Consent Form when you attend the first testing session Attend 3 testing sessions (approximately 2 hours per session): 1) before total knee replacement, 2) 3 months and 3) 6 months after total knee replacement. The testing will include several non-invasive measures of brain representations of the quadriceps muscles, central pain mechanisms, and motor function and questionnaires. Will I be paid to take part in the research study? You will be reimbursed ($50.00 per session) for travel and parking expenses associated with the research study visits. If you would like more information or are interested in being part of the study, please contact: Name: Dr Wei-Ju Chang Email: w.chang@neura.edu.au Phone: 02 9399 1260 This research is being funded by the Physiotherapy Research Foundation.  
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