title: An investigation of cortical neuroplasticity following stroke in adults: is there evidence for a critical window for rehabilitation?
abstract: BACKGROUND
  Evidence in animal stroke models suggests that neuroplasticity takes place maximally in a specific time window after an ischaemic lesion, which may coincide with the optimal time to intervene with rehabilitation. The aim of this study is to investigate neurophysiological evidence for a "critical window" of enhanced neuroplasticity in patients following ischaemic stroke, and establish its duration. We will also investigate changes in cortical inhibition following stroke, and the influence this has on functional recovery.
  
  
  METHODS
  We will recruit participants recently admitted to the Stroke Unit of major metropolitan hospitals who have had a stroke and can provide informed consent. Participants will be excluded if they have any contraindications to Transcranial Magnetic Stimulation. We will compare neurophysiological outcomes in an age-matched healthy control group. We conservatively hypothesise a 5% increase in neuroplasticity at the optimal timing following stroke, compared to control participants, and require 43 patients following stroke to detect a significant difference with 80% power. The primary outcome is the change in the motor evoked potential (MEP) amplitude in a hand muscle, after the administration of a plasticity-inducing paradigm to the affected hemisphere. Secondary outcomes include measures of cortical excitability, intracortical inhibition and arm function.
  
  
  CONCLUSIONS
  The data from this trial will clarify whether there is a critical window for neuroplastic change in the brain following stroke. If so, intensive rehabilitation during this period could be more effective, reducing long-term disability and the cost burden of stroke.
authors.affiliation: Alliance for Research in Exercise, Nutrition and Activity and International Centre for Allied Health Evidence, Sansom Institute for Health Research, School of Health Sciences, University of South Australia, GPO Box 2471, Adelaide, SA, 5001, Australia. michelle.mcdonnell@unisa.edu.au.
authors.forename: Michelle N
authors.initials: MN
authors.lastname: McDonnell
authors.affiliation: Stroke Research Programme, School of Medicine, South Australian Health and Medical Research Institute, University of Adelaide, Adelaide, Australia. simon.koblar@adelaide.edu.au.
authors.forename: Simon
authors.initials: S
authors.lastname: Koblar
authors.affiliation: Sobell Department of Motor Neuroscience, University College London Institute of Neurology, Queen Square, London, England. n.ward@ucl.ac.uk.|UCLP Centre For Neurorehabilitation, Queen Square, London, England. n.ward@ucl.ac.uk.|The National Hospital for Neurology and Neurosurgery, Queen Square, London, England. n.ward@ucl.ac.uk.
authors.forename: Nick S
authors.initials: NS
authors.lastname: Ward
authors.affiliation: Sobell Department of Motor Neuroscience, University College London Institute of Neurology, Queen Square, London, England. j.rothwell@ucl.ac.uk.
authors.forename: John C
authors.initials: JC
authors.lastname: Rothwell
authors.affiliation: Neuromotor Plasticity and Development Research Group, Robinson Research Institute, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, Australia. brenton.hordacre@adelaide.edu.au.
authors.forename: Brenton
authors.initials: B
authors.lastname: Hordacre
authors.affiliation: Neuromotor Plasticity and Development Research Group, Robinson Research Institute, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, Australia. michael.ridding@adelaide.edu.au.
authors.forename: Michael C
authors.initials: MC
authors.lastname: Ridding
mesh_terms: D000328:Adult; D019054:Evoked Potentials, Motor / Q000502:physiology*; D006225:Hand / Q000503:physiopathology; D006801:Humans; D018482:Muscle, Skeletal / Q000503:physiopathology; D009473:Neuronal Plasticity; D020127:Recovery of Function / Q000502:physiology; D000071939:Stroke Rehabilitation; D050781:Transcranial Magnetic Stimulation / Q000379:methods*