Methods for Quantifying the Role of Mood and Cognitive Function in Gait

1
Methods for Quantifying the Role of Mood and
Cognitive Function in Gait
Jeffrey M. Hausdorff, PhDLaboratory for Gait
Neurodynamics, Tel-Aviv Sourasky Medical Center
Department of Physical Therapy, Sackler School
of Medicine Department of Medicine, Harvard
Medical School Bethesda, Maryland September 2007
Do these studies tell us about causal
relationships among Triad Members?
2
POINTS TO BE DISCUSSED

• How to study mobility as a function of mood and
  cognitive function?
• Whats automaticity?
• Is gait automatic?
• Dual tasking
• Plasticity of the motor-cognitive competition
• Why are certain gait changes predictive of
  dementia?

3
Whats automaticity?

• Automatic movements are executed without
  attention being clearly directed towards the
  details of the movement.
• Automaticity is common, especially for movements
  that require low levels of precision or for
  movements that are frequently made.
• (Bernstein 1967, from Wu and Hallet 2005)

4
Gait / Mobility Assessment

• Wearable systems
• Footswitches, insoles
• Accelerometers
• Gyroscopes
• Goniometers
• Actigraphs
• Gait Mats
• Camera-based systems

5
Which parameters of gait to measure in order to
test automaticity?

• Gait Speed / Stride Length (pace)
• Cadence / Stride Time (rhythm)
• Swing / Stance / Double Support time
• 
  (dynamic balance)
• Stride-to-Stride Fluctuations (variability)
• Stride width, asymmetry, toe clearance
• All of these inter-related (just like cognitive
  domains inter-related, but there is unique
  behavior as well)
• J Verghese et al.
  JNNP 2007

6
Gait Variability
F

• How does one stride differ from the other in time?

7
A closer look reveals Stride-to-Stride
Fluctuations
8
Increased Gait Variability in Fallers
Time (min)
Time (min)
Hausdorff et al., Arch Phys Med Rehabil, 1997
9
Studies that Have Found Increased Gait
Variability in Fallers

• Elderly fallers
• Maki Barak et al. Springer et al. Menz et al.
  Auvinet et al.
• Peripheral neuropathy
• Richardson et al. DeMott et al.
• Parkinsons disease
• Schaafsma et al.
• Alzheimers disease
• Sheirdan et al. Nakamura et al..
• Higher level gait disorders
• Herman et al.

10

• Arguments in favor of Automaticity
• Decerebrate cats can walk
• Infants can generate locomotor pattern
• Adults can walk, talk, chew gum etc.
• Imaging studies
• PET and SPECT studies found no evidence for
  activity in areas associated with cognitive
  function during bi-pedal movements (bicycling)
  and paced walking (Christensen et al 2000,
  Fukuyama et al 1997)

11
Findings supporting the idea that gait is not
automatic
12
Dual Tasking

• Simultaneous performance of two tasks
• A common paradigm for studying the attentional
  demand of a given task
• Requires dividing attention,
• an executive function ability

13
Dual tasking
500 493 486 479 472 465 458 451 444 437 430
423

• Commonly Used Dual Tasks
• Talking while walking
• Arithmetic
• Backwards counting, subtractions
• Phoneme monitoring
• Alphabet recital (backwards, forward, skipping)
• Memorization
• Verbal fluency
• GoNoGo tests
• Motor tasks

14
Effects of Dual Tasking on Gait Variability in
Alzheimers Disease
Dual Task Walking
Routine Walking
Sheridan et al., 2003
15
Cognitive Challenge Increases Gait Variability
in Parkinsons disease
USUAL
Dual Tasking
Hausdorff et al., J Ger Psyc Neurol, 2003
16
DT Increases Gait Variability in PD, but not in
Controls
Yogev et al, Eur J Neurosci. 2005
17
Effect of Dual Tasking on Variability in PD
Yogev et al, EJN, 2005
18
Gait Speed Similar Effects in PD CONTROLS
CONTROLS
PD
none easy moderate
difficult
Cognitive load
19

• Since 1993-2007, at least 40 studies have
  examined DT effects on gait (and many more on
  balance)
• healthy young and older adults
• frail, fallers
• Parkinsons disease
• Alzheimers disease
• CVA, head injuries
• Negative effects on gait
• (i.e., speed, gait variability,
• stride length, etc)

20
What predicts gait variability during dual
tasking?

• Age?
• Usual walking abilities?
• Disease severity?
• Memory?
• Executive function?
• All of the above?

21
What predicts gait variability during dual
tasking?

• Depends on
• Population
• Dual task
• Instructions
• Specific measure

22
Correlations between Gait Variability and
Executive Function in PD

• Cognitive Load Level

23
Dual task Effects in Healthy Older Adults (n228)
Looking for a home, 2008??
24
Correlations between the dual task decrements and
cognitive function, mobility and affect
25
Do Freezers have Poorer Executive Function?
P0.05
P0.46
UPDRS III motor scores
Brixton scores of EF
FreezersN63
Non-Freezers N52
Non-Freezers N52
Freezers N63
26
Freezing of gait in Parkinsons disease why do
some patients freeze?
Starts Freezing when Subtracting (SFWS)
27
Task Specificity Are the observed properties
specific to gait?
28
Effects of Dual Tasking on Pedaling
No Dual Task
Dual Task
Freezing of Pedaling in PD?
29
TWO MODELS OF GAIT
30
Assessment of tapping and catching

• Computerized cognitive assessment system

Neurotrax Corp, NJ
31
Hausdorff et al., 2005
32
Association between walking and Stroop test
33
To tease out effects, Make Gait more
DifficultCorrelation between executive function
and walking speed in older personsInChianti
study, Ble et al 2005
Subjects with worse EF walk slower in a
challenging environment
34
The effects of mood on gait
http//guardian.curtin.edu16080/cga/teach-in/psyc
h/
35
Spatiotemporal gait patterns during over ground
locomotion in major depression compared with
healthy controlsLemke et al, J Psychiatric
Research, 2000
36
Hausdorff et al 2004
37
Effects of pharmacologic therapy
Paleacu et al 2007
38
Fear of falling
39
Correlation between Fear of Falling and Gait
Variability in patients with HLGD
r0.74 plt0.01
Herman et al., 2005
40
The Effects of Support (reducing FOF) on Gait
Speed in Patients with HLGD
Hand Holding improved speed Other
interventions did not
P lt .002
Normal Walker Guarding Hand
Balash et al., 2007
41
8weeks of Tai Chi for FOF in almost Frail
Elderly

• Tai Chi reduced FOF
• Compared to control group
• NO significant effect on GAIT SPEED

JG Zhang et al. 2006
42
Intervention Studies

• Can they tell us anything about the triad?
• Common cause or random?

43

• A gold standard for studying
• motor- cognitive associations
• RCT, double-blinded, in young old
• Measure gait neuro-imaging response to single
  and dual task
• Controlled intervention / DT training
• Compare change in performance across groups
• Change in cortical activation (pre-defined ROIs)
• Correlation of the two

44
TrainingInduced Functional Activation Changes in
Dual-Task Processing An fMRI Study Erickson et
al. 2007

• Training of visual RT as single dual tasks
• Most regions involved in dual task processing
  before training showed reductions in activation
  after training.
• Many of the decreases in activation were
  correlated with improved performance on the task.
  
• An area in the dorsolateral prefrotal cortex
  (DLPFC) showed an increase in activation for the
  training group for the dual task condition.

45
SP- single pure SM- single mixed DM- dual mixed
46
Effects of dual task training on postural
swayPellecchia GL 2005
47
Training of balance under single and dual task
conditions in older adults with balance
impairmentSilsupadol, Shumway- Cook, Woollacott
2006

• 3 patients were trained for 4 weeks, 3 times a
  week, 1 hour each session
• Patient 1- single tasks
• Patient 2- training of DT, instructed to share
  attention between tasks
• Patient 3 training of dual task, instructed to
  prioritize each time another task

48
Effects of Dual Task Training on Gait
49
Effects of training and detraining on the static
and dynamic balance in elderly fallers and
non-fallers a pilot studyToulotte et al 2006

• 16 older adults fallers and non- fallers
  trained for 3 month, twice a week, 1 hour each
  session
• Training included
• Strengthening exercise
• Balance exercise
• Flexibility exercise
• Walking with and without dual task exercises

50
Non-Fallers
3 months before
2 days before
2 days after
3 months after
Fallers
3 months before
2 days before
2 days after
3 months after
51
Effects of Methylphenidate (aka MPH, aka
Ritalin) Attention enhancer affects gait?
52
Effects of MPH in Children with ADHD
Gait variability while performing cognitive task
Without ritalin
placebo
With ritalin
Leitner et al. 2007
53
MPH Effects in Patients with PD
Auriel et al. 2006
54
Devos et al., JNNP 2006
55
Effects of Single Dose of MPH on Swing Time
Variability in Elderly
Placebo effects were NS P0.039 Pre vs. Ritalin
for Usual Walking P0.012 Pre vs. Ritalin for
Serial 3s
Ben-Itzhak et al., Neurology, 2007 (abstract)
56
1) If gait utilizes EF, is this a case of use
it or lose it? 2) If gait utilizes EF, subtle
changes in gait reflect subtle changes in EF?

Gait Changes Predict Vascular Dementia More than
Six Years in Advance
Verghese et al, NEJM, 2002
57
POINTS TO CONSIDER

• Different aspects of gait / mobility mood
  cognitive function (not necessarily sensitive to
  same inputs)
• To study these relationships
• Cross sectional (compare cognitive to mobility
  across different populations with known deficits)
• Neuro-Imaging (but difficult with gait)
• Manipulate the complexity of the gait task
• Intervene / change cognitive function
• Change / manipulate instruction set
• Compare across tasks

58
Suggestions

• Be more specific (not sufficient to say gait is
  not automatic)
• Need to better understand discrepant studies
• Need to quantify cognitive loading distinguish
  among different DTs
• Need to develop clinically relevant, quantifiable
  tests
• Because of triad, need to consider, mood, CF and
  mobility - not in isolation

59
CALL FOR PAPERS Special issue of the Journal of
Gerontology Medical Sciences The Role of Cortical
Function in Age-associated Changes in Balance and
Gait
II
February 22-24,2008 Amsterdam
60
A Lesson from Shrek

• Shrek Ogres are like onions.
• Donkey They stink?
• Shrek Yes. No.
• Donkey Oh, they make you cry.
• Shrek No.
• Donkey Oh, you leave em out in the sun, they get
  all brown, start sproutin' little white hairs.
• Shrek NO. Layers. Onions have layers. Ogres have
  layers. Onions have layers. You get it? We both
  have layers.
• Substitute gait and cognitive function for
• Onions and Ogres.

61
Gait
Thank you
Cognitive Function
Mood