Imaging Methods: Gait, Cognition and Mood

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Imaging Methods Gait, Cognition and Mood

• Richard Camicioli MD
• University of Alberta
• Edmonton, Alberta
• rcamicio_at_ualberta.ca

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Objectives

• To present approaches to the imaging
  investigation of age-related gait, cognitive and
  mood changes, emphasizing gait.
• To focus on various MRI approaches to the study
  of age-related gait change.
• To introduce functional imaging approaches.
• To highlight gaps and suggest directions for
  future research.

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Gait, Cognition, Mood
Gait
Cognition
Mood
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Study Design

• Single-case studies
• Case-series
• Correlative
• Case-control studies
• Selective
• Nested
• Longitudinal studies
• Cohort studies
• Population-based
• Selected samples
• Clinical trials

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Imaging Modalities

• Magnetic resonance imaging (MRI)
• White matter rating/quantitation
• Volumetric measurement
• Diffusion tensor imaging
• Magnetization transfer imaging
• Spectroscopy
• Functional MRI
• PET
• SPECT

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Case Studies and Case Series

• Clues and Correlates

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Group Studies

• Correlative Studies and Case-Controlled Studies

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White Matter Rating Scales

• Manolio
• Fazekas and Schmidt
• Scheltens
• Wahlund

Kapeller P Stroke 2003
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ARWMC Ratings

• White matter lesions
• 0 No lesions (including symmetrical well-defined
  caps and bands)
• 1 Focal lesions
• 2 Beginning confluence of lesions
• 3 Diffuse involvement of an entire region
• Basal ganglia lesions
• 0 No lesions
• 1 1 focal lesion (lt5mm)
• 2 gt1 focal lesion
• 3 Confluent lesions

Wahlund LO Stroke 2001
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Quantitative White Matter Measurement

• More reliable than visual rating
• More amenable to longitudinal rating
• Less prone to floor or ceiling effects
• More readily allows for anatomic specification

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Longitudinal White Matter Change

• Annual change in white matter signal (but not
  change in grey matter, white matter or CSF
  volume) associated with impaired gait and balance
  (Short Physical Performance Battery)
• Wolfson L et al J Neurol Sci 2005
• Only 14 total subjects
• Other studies have similar findings
• Whitman G et al Neurology 2001
• Longidudinal follow up of 70 older people

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Age-Related White Matter High Signal and
Depression

• Some studies (not all) have found that ARWMD is
  related to depressive symptoms
• LADIS study suggested that deep (not
  periventricular) changes are associated with
  depressive symptoms
• Meta-analysis suggests both are associated
• Correlation with outcomes in some studies
• Poorer response to therapy and persistence
• Longitudinal changes have been inconsistently
  related to symptoms
• Chen PS Int Psychogeriatr 2006 Verslius CE Int J
  Geriatr Psychiatry 2006

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Volumetric Approach

• Volumetric measurement of hippocampus and
  amygdala have been used in studies of cognition
  and mood
• ROI and automated methods
• Automated method allow for segmentation of grey
  and white matter
• Voxel-based morphometry allows for unbiased
  comparison of groups and correlation with measures

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Diffusion Tensor Imaging

• Diffusion tensor imaging is based on the
  measurement of diffusivity of water molecules
• Allows for assessment of integrity of white
  matter pathways
• Fractional anisotropy (FA) and apparent diffusion
  coefficient (ADC) usually change in opposite
  direction in relation to disruption
• Complements other methods have also been used
  (ie. Magnetization transfer and MR spectroscopy)
• Pathways can also be mapped using diffusion
  tensor tractography
• These methods are being applied to cognition and
  mood but should be applicable to gait.

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Functional Imaging Modalities MRI, PET and SPECT

• Measure changes during task performance, compared
  to a baseline task
• Walking is challenging to measure
• MRI and PET affected by movement artifact
• Studies have looked at lower extremity movements
  and walking imagery
• SPECT has been used to look directly at walking

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Conclusions

• Various study designs have provided useful
  insights into the neural correlates of gait,
  cognitive and mood impairment
• An attainable goal is to examine these together
  to determine their unique and overlapping basis
• MRI techniques under development will likely
  provide further insights
• Other imaging and measurement approaches will
  provide convergent evidence and unique insights
• Multimodal imaging is an important target

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Suggested Future Directions

• Further application of new imaging techniques
  (DTI, high resolution MRI, etc) will provide
  additional insights into the neural basis of
  gait, cognitive and mood changes with aging
• Convergent approaches improve confidence and
  provide complementary information
• Large scale epidemiological studies should
  include imaging
• Studies should examine gait, cognition and mood
  together
• High-risk investment may allow the development to
  measure the neural correlates of walking in
  real-time