Brain plasticity post stroke

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1 Brain plasticity post stroke NICK WARD NATIONAL HOSPITAL FOR NEUROLOGY AND NEUROSURGERY UCL INSTITUTE OF NEUROLOGY BASP: Advanced Stroke Medicine, 24 th March 2012

2 after thrombolysis...

3 stroke damage Brain Plasticity & Stroke Stroke

4 Stroke stroke damage damaged pathways damaged cortex

5 Rehabilitation Rehabilitation is a process of active change by which a person who has become disabled acquires the knowledge and skills needed for optimum physical, psychological and social function 1. Assessment 2. Goal setting 3. Intervention i. treatments, which affect the process of change ii. support, which maintains the patient's quality of life and his or her safety 4. Evaluation to check on the effects of any intervention How is that long term improvement taking place? Should we challenge the idea of the recovery plateau?

6 Rehabilitation we can avoid the complications of stroke

7 PLASTICITY is Brain Plasticity & Stroke What is brain plasticity? the formation of new functional connections between nerve cells the withdrawal of inappropriate connections the modulation of strength between the cell-cell connections called synapses changes that occur in the organization of the brain as a result of experience (and that improve function)

8 What is brain plasticity? COMMUNICATION LTP INDUCTION A Na + N Ca 2+ Mg 2+ activity cortical plasticity lesion induced changes inactivity

9 What do we mean by reorganisation? Brain Plasticity & Stroke What is brain plasticity? of plasticity but is hardwired and immutable. Once damage occurs, cortical neurons either die or at best

10 Can we see it? What do we mean by reorganisation? Dendritic growth in vivo Axon arborisation in vivo Niell et al., Nat Neurosci 2004; 7: Hua et al., Nature 2005; 434: dendrites axon

11 Can we see it? Dendritic growth in vivo (600:1 time lapse) Niell et al., In vivo imaging of synapse formation on a growing dendritic arbor. Nat Neurosci 2004; 7:

12 What is brain plasticity? hardwired and immutable. Once damage occurred, cortical neurons either died or at best did not change The structure of the brain is constantly changing this is the basis of learning both in health and disease However, it requires to take advantage of these processes and create new connections and networks

13 How to drive plastic change? Motor practice/ Motor learning Constraint induced therapy Robotic assisted devices Virtual environments Task specific training is better than general exercise 2. works better in patients with reasonable residual motor control 3. optimal dose is important but not clear 4. Better retention and generalisation can be achieved by: a) Distributed practice - frequent and longer rest periods b) Variable practice - varying parameters of task c) Contextual interference - random ordering of related tasks

14 How to enhance plastic change? Enhancing Plasticity Cortical stimulation with task oriented training e.g. rtms or TDCS Motor imagery, action observation Pharmacotherapy e.g. amphetamine, DA agonists (DARS), Fluoxetine (FLAME) Enhancing Wiring

15 Barriers to translation? likelihood of response [Ward, CoN 2008]

16 Driving plastic change input input input input Ward and Cohen, Arch Neurol 2004

17 Lesion induced brain reorganisation Affected hand Unaffected hand

18 Variability in lesion induced brain reorganisation - fmri Ward et al., Brain 2006 affected hemisphere more CS damage less CS damage

19 Variability in lesion induced brain reorganisation - fmri CSS Integrity CSS Integrity CSS Integrity Ward et al., Brain 2006 affected hemisphere more CS damage less CS damage

20 Is this reorganisation doing something useful? TMS to premotor cortex after stroke more effect in good recoverers more effect in poor recoverers affected hemisphere unaffected hemisphere Fridman et al, 2004 Johansen-Berg et al, 2002

21 Variability in lesion induced brain reorganisation Disruption to CST leads to a shift of activity away from primary to secondary motor areas Ipsilateral and secondary motor areas may be using non-monosynaptic pathways These areas often associated with motor synergies e.g. flexor synergy Can this be functionally useful? affected hemisphere Ward et al 2003a, 2003b, 2004, 2006, 2007

22 Variability in lesion induced brain reorganisation A affected side infarct 10 days post stroke 17 days post stroke 24 days post stroke 31 days post stroke 3 months post stroke B affected side OUTCOMES Barthel ARAT GRIP NHPT Patient A 20/20 57/ % 78.9% Patient B 20/20 57/ % 14.9%

23 Treatment induced changes in brain reorganisation Before and after treatment fmri studies what do they tell us? Hodics, Cohen & Cramer, 2007

24 Treatment induced changes in brain reorganisation Variability amongst trial designs, although all post vs pre design The majority of studies were performed on well-recovered patients Treatment associated increase in activation in ipsilesional M1, PMd, SMA Pre-Tx Post- Tx However, in patients with more severe baseline deficits, post treatment increases in the contralesional motor regions, and shifts in laterality towards the uninjured hemisphere have been found (Schaechter et al, 2002, Luft et al., 2004) Johansen-Berg et al. Brain 2002 Carey et al. Brain 2002

25 Implications for neurorehabilitation trials unaffected affected unaffected affected Will the same treatment strategy work in these patients?

26 Assessment of structural damage

27 Assessment of structural damage

28 What is brain plasticity? Stinear, C. M. et al. Brain : Copyright restrictions may apply.

29 In summary The brain is even months and years after stroke Some rehabilitation treatments take advantage of plasticity (as long as you avoid the complications of stroke) Brain imaging might help us to understand who will benefit from which type of treatment

30 Acknowledgements FIL: Richard Frackowiak Will Penny Jennie Newton Peter Aston Eric Featherstone ABIU/NRU: Alan Thompson Martin Brown Richard Greenwood Diane Playford Katie Sutton All nurses, physios, OTs, SLTs SOBELL DEPARTMENT : Marie-Helen Boudrias Holly Rossiter Chang-hyun Park Karine Gazarian Sven Bestman John Rothwell Penny Talelli n.ward@ucl.ac.uk FUNDING:

Motor recovery after stroke

Motor recovery after stroke NICK WARD, UCL INSTITUTE OF NEUROLOGY, QUEEN SQUARE n.ward@ucl.ac.uk Follow us on twitter @Wardlab UCL Institute of Neurology MSc Lectures, Queen Square, March 2014 Recovery After Stroke: Neurorehabilitation