1. Sensory and cognitive impairments in subjects with Post-stroke Hemiparesis
Dr. Deborah Larsen, PT, PhD
Alexandra Borstad, PT, PhD
Parminder Kaur, PT, MPT
Petra Schmalbrock, PhD

2. Sensory and Cognitive Deficits Post-Stroke
Sensory (SD) and mild cognitive deficits (MCD) often go undiagnosed post-stroke.
Post stroke cognitive impairments are progressive and persistent in nature, reaching dementia by 5 yrs in % of patients with non-severe ischemic stroke.
Somatosensory impairments are reported in 53-60% of stroke survivors and include both proprioceptive and cutaneous input.
Almost 90% of stroke survivors demonstrate either SD or MCD and no study has looked at the relationship between these deficits.

3. Post stroke Impairments
Sensory Impairments
Motor impairments
Cognitive impairments

4. Hypotheses
Post-stroke subjects will perform worse on measures of sensory discrimination and cognition than age- matched peers.
Deficits in sensory and cognitive function will relate to poorer motor function.
Functional MRI analyses will differentiate activation patterns between controls and post-stroke participants.

5. Subjects
14 controls,12 chronic post-stroke subjects were tested in a single behavioral and imaging session.
Inclusion criteria - 1) single hemiparetic documented stroke; 2) aged 21-85; 3) hand movement sufficient to grasp and release objects; 4) ability to understand test instructions
Exclusion criteria -1) prior diagnosis of cognitive (eg. dementia), sensory (eg. neuropathy) or neurologic (eg. Parkinsons) disorders; 2) metal device or other incompatibility with MRI testing; 3) Mini Mental Exam <24.

6. Materials and methods Motor Sensory Functional MRI Cognition
Hand Active Sensation Test (HASTe),
Brief Kinesthesia Test (BKT),
Form Perception Test (FPT);
Cognition
N-back (1 back & 2 back)
Paced Auditory Serial Addition Test (PASAT; 2 & 3 sec),
Choice Reaction Test (CRT)
Motor
Box and Blocks (BBT),
9 Hole Peg (9NP)
Functional MRI
Sensory (brush discrimination)
Paced Visual Serial Addition Test (PSVAT)

7. Results

8. Functional MRI Data
Stroke subjects performed worse than their matched controls on both sensory & cognitive tests
Sensory & cognitive scores correlated strongly with each other and with motor scores (BBT)
Networks supporting sensory discrimination and working memory overlap with the parietal lobe and dorsal frontal cortex playing a key role in both tasks.
Post stroke subjects demonstrated disruption of both networks (cognitive and sensory tracts) compared to controls.

9. Sensory Group Differences
Task
Affected
Unaffected
Brief Kinesthesia
Prob > t
Prob > t
Form Perception Test
Prob > t ,
Prob < t
Brush discrimination
Prob >t
Not significant
Monofilament (pinky)
Monofilament (index)

10. Cognitive Testing: Group Comparisons
Task
Reaction time
Prob > t
PASAT – 2 seconds
Prob < t
PASAT – 3 seconds
Prob < t
2 – back (accuracy)
Prob < t
1 – back (accuracy)
Prob < t

11. Sensory task -Right Brush discrimination (Z> 3.0, p<.01)
Post stroke group
L – postcentral gyrus
R – Supramarginal gyrus
L – Precentral gyrus
Control group
L – Parietal operculum
R – Inferior frontal gyrus
R – Cerebellum
R – paracingulate cortex
L – Middle Frontal gyrus

12. Cognitive task – PVSAT Post stroke group Control group
L – Middle Frontal Gyrus
L – Frontal Orbital Cortex
Control group
L – Supramarginal Gyrus
Cerebellum
L – Inferior Temporal gyrus
R – Occipital Pole
R - Middle Frontal Gyrus
L – Thalamus
L – Middle Temporal gyrus
L - Precuneus

13. Areas of overlap for cognitive and right brush discrimination tasks
Rt supplementary motor area
Lt angular gyrus
Lt supramarginal gyrus
Rt angular gyrus
Middle frontal gyrus
Lt precentral gyrus
Lt & Rt frontal operculum cortex

14. Areas of overlap for cognitive & sensory tasks
R – Supplementary Motor area
L – Angular Gyrus
R – Middle frontal gyrus
R – Angular Gyrus
L – Supramarginal gyrus
L & R frontal operculum
L – Precentral gyrus
Blue = sensory
Orange = cognitive

15. Correlations between Sensory, Cognitive & Motor Measures
HASTe strongly correlated with PASAT (r=.722, p<.0001).
PASAT strongly correlated with BBT (r=.685, p<.001)
HASTe moderately correlated with BBT (r=.431, p<.05).

16. Summary of Results
Post-stroke subjects demonstrated disruption of both networks.
Sensory and working memory deficits are common after stroke and may be related to disruption of common neural networks.
These overlooked deficits impact motor recovery.
Stroke rehabilitation protocols continue to focus on motor impairments, ignoring the contributions of concomitant sensory deficits.

17. Clinical significance
Therapists need to include measures of sensory discrimination and cognition within their standard assessment procedures for stroke survivors.