ReTurnS: Rehabilitating Turning coordination after Stroke

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ReTurnS Rehabilitating Turning coordination
after Stroke
Kris Hollands

• Dr. Paulette van Vliet
• Principal Investigator, School of Health Sciences
• Dr. Mark Hollands
• Co-investigator, School of Sport and Exercise
  Sciences
• Prof. Alan Wing
• PhD co-supervisor, School of Psychology

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Walking Changing Direction

• The ability to effectively alter locomotor
  patterns to change direction is essential for
  daily activities

• A large proportion of falls in community dwelling
  stroke survivors occurs while changing direction
  during walking (Hyndman, D., Ashburn, A. Stack,
  E, 2002).

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Walking Changing Direction Following Stroke

• Stroke patients have many adaptations to their
  locomotor pattern during straight walking
• Slower speed
• Altered stride parameters
• Increased variability
• Postural biases
• Increased metabolic costs
• 1 case-series (n2) examining turning ability of
  stroke patients indicates biomechanics of
  reorientation is altered following stroke
  (Lamontagne et al, 2007)

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Purpose

• How are direction changes achieved with an
  already altered basic locomotor pattern?
• Can stroke patients alter walking direction at
  the last moment in response to environmental
  demands?
• Explore contributions of cerebral subcortical
  structures to the control of adaptive locomotion.
  

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right
left
0
-45
45
5 trials Early Late cues each leg lead
5 trials Early Late cues
5 trials Early Late cues
trigger mat
3 m
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Participants

• 15 hemiparetic patients gender and age-match
  controls
• mean age 61 yrs, range 40-83
• Agematches 1yr of stroke counterpart
• Chronicity post stroke
• mean 49 mths, range 11-144
• Lesion locations
• 8 right hemisphere, 6 left hemisphere 1
  cerebellar
• 6 basal ganglia lesions
• Severity
• 6 severe, 3 moderate, 6 mild

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Overall Turn Performance

• Stroke patients were able to complete the turn in
  the same time frame as healthy counterparts
• control 3.2s 1.09
• stroke 2.9s .86
• Magnitude of turn is achieved by both groups
• Control 48.1 deg 4.6
• Stroke 46.6 deg 5.7
• Both groups employed the same stepping strategy-
  step wide to turn
• No differences if the turn is towards the paretic
  or non-paretic side.

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Axial Segment Reorientation
Late Cue Condition
Onset of Segment Reorientation w.r.t. cue
delivery (s)
Early Cue Condition
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Basal Ganglia lesions alter axial segment control!
Onset of Segment Reorientation w.r.t. cue
delivery (s)
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Discussion

• Able to carry out turns in the same time frame
  even when turns are unplanned
• Preservation of stepping strategies
• Overall maintenance of sequence of axial segment
  reorientation
• Delayed initiation of turning sequence in
  pre-planned turns
• Initiation of turn particularly poor in patients
  with lesions involving the BG.
• Improved by visual stimulus in LC condition!!

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But

• We dont yet know if delayed initiation has any
  functional significance
• i.e. could this underlie falls epidemiology?
• Possibility that the turn was too small to
  elucidate biomechanical differences in turning
  which could account falls history.

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Turning 180degrees in the Timed Up and Go
Differences between Stroke survivors with and
without falls history
Time taken to complete the TuG is greater for
stroke survivors than controls BUT there are no
differences in TuG time according to falls history
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Preserved Axial segment coordination during
turning in the TuG
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Clinical implications Interventions for Attention

• Falls occur during turning following stroke
  despite preservation or recovery of movement
  patterns
• Majority of falls reported occurred due to lapse
  in concentration
• Improvement in turn initiation with external
  visual cues (particularly in patients with BG
  lesions) has also been seen in PD patients
• Improvement of turning and walking in PD patients
  thought to be due to improved focus of attention
  (Azulay, 2006)

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Future Directions

• Effects of Visual and Auditory Cues on Turning
  following stroke
• Role of specific neural networks in the control
  of walking and turning
• Basal Ganglia
• Recovery of turning movement patterns 6mths-2yrs
  post stroke
• Is there a need for targeted intervention and
  can turning coordination be improved by
  rehabilitation?

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Stepping strategy
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45
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Widening of ultimate transition step indicates a
side-step turn strategy is adopted by both groups