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

Motor Impairment

RESEARCH CENTRE

About

Motor impairment is evident in a range of diseases and health conditions, including:

  • stroke;
  • spinal cord injury;
  • multiple sclerosis;
  • brain injury;
  • Parkinson’s disease;
  • neuromuscular diseases;
  • major orthopaedic injury;
  • cerebral palsy; and
  • frailty associated with old age.

Motor impairment can also result from major cardiac, respiratory, and endocrine disease.

Different impairments feature in different conditions. For example, weakness is a feature of spinal cord injury, fatigue is prominent in multiple sclerosis, impaired sensation and movement commonly occurs after stroke, impaired balance develops in Parkinson’s disease, and cerebral palsy is often accompanied by contracture. Often several impairments co-exist in a single person and the prevalence of all these impairments increases with advancing age.

Motor impairment is extremely prevalent in the Australian population and is a major health problem. The reasons are threefold: it is a feature of prevalent health conditions such as stroke (in 2003, approximately 350,000 Australians experienced a stroke); the incidence within these conditions is high (half of the patients admitted to hospital with stroke develop at least one contracture within six months [1]); and these impairments often persist, typically resolving slowly or not at all.

What do we know about the mechanisms?
Motor impairment is broadly caused by:

  • peripheral problems affecting muscles;
  • problems in the central nervous system affecting output to muscles; and
  • sensory problems affecting muscles, movement and balance.

While much is known about the mechanisms of some motor impairments, such as muscle weakness in frail elderly people, little is known about others, such as the contractures in people who have had a stroke.

Similarly, while interventions for some impairments (such as exercise for impaired balance in the frail elderly) are supported by high-quality randomised controlled trials [2], interventions for other motor impairments (such as strength training for incompletely paralysed muscles) lack even a basic understanding of neurophysiological mechanisms.

Because motor impairment features in diverse health conditions as well as ageing, and because it is not a discrete diagnosis, it has not been the focus of targeted research programs. We believe that greater recognition and understanding of motor impairment can lead to better health outcomes.

References
1: Kwah LK, Harvey LA, Diong JLH & Herbert RD. (2012). Half of those who present to hospital with stroke develop at least one contracture within six months: a prospective cohort study. J Physiother 58, 41-47.
http://www.ncbi.nlm.nih.gov/pubmed/22341381

2: Sherrington C, Whitney JC, Lord SR, Herbert RD, Cumming RG & Close JCT. (2008). Effective approaches to exercise in the prevention of falls – a systematic review and meta-analysis. J Am Geriatr Soc 58, 2234-2243.
http://www.ncbi.nlm.nih.gov/pubmed/19093923

Chief Investigators

Professor Simon GANDEVIA FAA FRACP DSc MD PhD MB BS
Deputy Director, Neuroscience Research Australia (NeuRA)
NHMRC Senior Principal Research Fellow

Professor Stephen LORD DSc PhD MA
NHMRC Senior Principal Research Fellow, Neuroscience Research Australia (NeuRA)

Professor Rob HERBERT PhD MAppSc
NHMRC Principal Research Fellow, Neuroscience Research Australia (NeuRA)

Associate Professor Janet TAYLOR MD MBiomed E MB BS
NHMRC Senior Research Fellow, Neuroscience Research Australia (NeuRA)

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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.  
PROJECT