This study examined eye-hand coordination and postural stability in 15 community-dwelling stroke survivors. It found that stroke survivors had slower reaction times and longer movement times when performing a finger pointing task with their paretic arm, especially when standing. Total sway and anterior-posterior displacement also increased when pointing with the paretic arm while standing. There were correlations between better eye-hand coordination and greater muscle strength, functional reach, and balance. The findings suggest that rehabilitation should train eye-hand coordination in both sitting and standing postures and address balance to improve upper limb function during daily activities.

1. TITLE OF THE JOURNAL
Authors & Reference
Presenter : Phinoj K. Abraham MOTh(Neurosciences)

2. OBJECTIVES
 To discuss the findings of recent original research article on eye-
hand coordination in stroke survivors while sitting and standing
and its relationship with sensorimotor performance.
 To critically analyze this scientific paper
 To discuss the clinical implication of the study findings in our
setting
2

3. Key Terms
• Finger Pointing
• Stroke
• Sensorimotor Impairments
• Postural Stability

4. Abbreviations
• FRT – Functional reach Test
• TUG – Timed-up-and-go test

5. Introduction
Background
• Eye-hand coordination is involved in any visually
guided, goal-directed use of the hand
• It is crucial for reaching for and manipulating the tools
of daily activities
• Coordination among vision, limb proprioception, and
movement of the shoulder, elbow, wrist, and fingers is
essential for successful reaching

6. • Postural stability is the ability to integrate sensory
information from the proprioception, visual, and
vestibular systems to make the motor responses
needed to maintain the center of gravity within the
base of support
• Good postural stability is extremely helpful in
performing many of the activities of daily living.
Introduction
Background

7. Introduction
Lacunae of research
• Most investigations of eye-hand coordination have
been performed in a sitting position, which involves
less demand for postural stability, so the
interrelationship between eye-hand coordination and
postural stability is not very clear

8. Introduction
Need of the study
• Stroke often induces persistent sensorimotor impairments
such as muscle weakness, poor proprioception, and
impaired upper extremity function.
• Often, eye-hand coordination and postural stability are
also degraded.
• A better understanding of the relationships among all
these sequelae promises to help in the design of
rehabilitation interventions

9. Aims of the study
1. to examine the effects of stroke on eye-hand
coordination with a concurrent postural stability task
2. to study the relationship among sensorimotor
performance, eye-hand coordination, and postural
stability

10. Methodology
Research Design
• Cross sectional study

11. Methodology
Sampling
• Sample population
– community-dwelling stroke survivors
• (9 men and 6 women; mean [SD] age, 58.7 [7.5]
yrs)
• Sample Size
– 15
• Sample Procedure
– Convenient Sampling

12. Methodology
Inclusion Criteria
1. MMSE of at least 24
2. Snellen visual acuity of at least 20/40 (with or without
any visual correction device)
3. Shoulder flexion of at least 90 degrees,
4. Lack of elbow extension not more than 30 degrees,
5. Wrist extension at least 0 degrees, and
6. Able to stand independently

13. Methodology
Exclusion Criteria
1. hemianopia (using Star Cancellation test),
2. visuospatial neglect (using Rapid Confrontation
Screening test)
3. amputation of the index finger, and
4. Ashworth Scale scores 3 or above for upper and
lower limbs

14. Methodology
Materials & Methods
• The subjects underwent the following
assessments:
1. knee proprioception,
2. muscle strength,
3. balance, and
4. eye-hand coordination.

15. • The subjects’ knee proprioception was
assessed using a validated limb-matching task
• The subjects were instructed to move their
paretic leg to a position somewhere in the
midrange of normal joint excursion, then move
the non-paretic leg to the same position as the
paretic leg. (with eyes closed)
Assessment of knee proprioception
Methodology
Materials & Methods

16. Methodology
Materials & Methods
• Assessment of muscle strength
– the shoulder flexors, elbow flexors, wrist extensors,
quadriceps, and hamstrings were tested with a Nicholas
handheld dynamometer
• Assessment of Balance
– Functional reach test
• Assessment of eye-hand coordination
– fast finger-pointing task
• Functional Mobility
– Timed-up-and-go test

17. • Subjects were instructed to use their index fingers to touch
a moving target appearing on a visual display unit,
contralateral side to the arm being tested
– In sitting
– In standing
• the upper edge of the screen was at the subject’s eye level
• the distance between the screen and the subject was equal
to the subject’s arm length
• An accelerometer was fixed to the subject’s ulnar styloid
process – to assess the reaction time
Assessment of eye-hand-coordination
Methodology
Materials & Methods

18. • Subjects were instructed to touch the target as quickly and
accurately as possible
• The task was performed
– 10 times in sitting – while sitting in a non rotating chair with
backrest
– 10 times in standing – while standing barefoot on a force plate
• The sequencing of the Ax was as follows: pointing with
1. the unaffected arm while sitting
2. the affected arm while sitting
3. the unaffected arm while standing, and
4. the affected arm while standing
Assessment of eye-hand-coordination Contd..
Methodology
Materials & Methods

19. • The protocol produced repeatable results with healthy
elderly subjects,1 and the methodology has been used to
study the eye-hand coordination of stroke survivors in a
previous study.2
Assessment of eye-hand-coordination Contd..
Methodology
Materials & Methods
1. Gao L, Ng SM, Kwok WY, et al: Eye-hand coordination and its relationship with sensori-motor
impairment in stroke survivors. J Rehabil Med 2010;42:368Y73
2. Kwok JC, Hui-Chan CW, Tsang WW: Effects of aging and Tai Chi on finger-pointing toward
stationary and moving visual targets. Arch Phys Med Rehabil 2010;91:149Y55

20. Operational
Definitions
• Reaction time was the time between the appearance of the
moving visual signal on the screen and the onset of arm
movement
• Movement time was the time from the onset of arm
movement to touching the visual target.
• Accuracy was the absolute deviation of the touch position
from the center of the target at the moment of touching.

21. Outcome
Measures
• To Assess
– Reaction Time : Accelerometer
– Total Sway path and displacement : Force plate

22. Statistical
Analysis
• To Check Normality : Kolmogorov-Smirnov test
• To compare reaction time : paired ‘t’ test
• To check the correlation between the knee proprioception,
muscle strength, hand grip strength, functional reaching and
TUG (time Up and Go test) results and performance in the fast
finger –pointing task : Pearson r
– SPSS software version 17 was used for computation
– Significance threshold was set at 0.05

23. Results
Eye-Hand Coordination Performance
1)
2)
3)
4)
Reaction
Time
Standing
Paretic Side
Non Paretic
Side
Movement
Time
Sitting
Paretic Side
Non Paretic
Side
Movement
Time
Standing
Paretic Side
Non Paretic
Side
Avg. Movement
Time
Sitting
Standing
P = 0.026
P = 0.001
P = 0.001
P = 0.045

24. Results
Postural Stability
Total Sway Standing
Paretic
Side
Non Paretic
Side
P = 0.009
AP
Displacement
Standing
Paretic Side
Non Paretic
Side
P = 0.002
AP : anteroposterior

25. Results
Correlations
• There was significant negative correlation between
1. Movement time on paretic side while standing vs.
functional reach score
2. Movement time – while sitting & standing vs. Hand grip
strength
3. Movement time while sitting vs. wrist extensor strength
4. Shoulder flexor strength Vs. accuracy in sitting

26. • There was, however, no significant correlation
between eye-hand coordination and
1. postural stability, (Assessed with FRT)
2. TUG times,
3. knee proprioception, or
4. leg strength
Results
Correlations Contd..

27. Discussion
Effect of stroke on Eye-Hand coordination
Paretic Side vs. Nonparetic Side – Reaction Time
• FINDING: Slower Reaction time – with paretic arm
– during finger pointing task – while standing
 Previous study reported that stroke survivors have
slower VERBAL reaction time in sitting vs. standing –
due to ‘dual task paradigm’ (Brown et al, 2002)
 ‘…in this study, slower reaction times in the finger-
pointing task’

28. • FINDING: The paretic side had a longer movement
time than the non-paretic side – in sitting and
standing
– Impaired isolated movement (Zackowski KM,2004)
– Abnormal joint torque production (Dewald 2001)
– Impaired joint coordination (Cirstea 2000)
– Less flexible joint after stroke (Reisman 2003)
Discussion
Effect of stroke on Eye-Hand coordination
Paretic Side vs. Nonparetic Side – Reaction Time

29. • FINDING: In this study, some subjects used trunk
displacement as a kind of compensatory strategy in
the fast finger-pointing task when standing.
• This shortened the distance to the moving visual
target, so the movement time was shorter when
standing than when seated.
Discussion
Concurrent postural stability and Eye-
Hand coordination
Sitting Vs. Standing – Movement Time

30. • FINDING: ….the total sway path and AP displacement
increased when the subjects reached for a moving visual
target with their paretic arms
– Stroke survivors shows decreased anticipatory
activation (Shumay-cook 2007)
– Attention capacity is decreased after stroke (Marshal 1997)
– The resources allocated to postural stability were
reduced when the subjects had to tackle an attention-
demanding concurrent task. (Bensoussan L, 2007)
Discussion
Total sway path and Anterior Posterior
Displacement

31. • FINDING: There was no significant correlation between
movement time and shoulder flexors strength found in this
study
– There are 2 movement strategies in fast finger pointing,
Deltoid and Biceps Brachii Strategies
– Post-stroke subjects normally have elbow flexion at the
beginning of reaching
Discussion
Sensorimotor Performance and Eye–Hand
Coordination
Limb Function

32. • FINDING 1: Faster movement time on the paretic side was
associated with better forward reaching in the standing
position.
– This indicated that better balance might be helpful for fast finger-
pointing.
• FINDING 2: there was no relationship found between
pointing speed and TUG times.
– A TUG task might challenge subjects’ functional mobility, but it was
not specific enough to relate to quiet standing.
Discussion
Balance

33. Clinical
Relevance
• Postural stability was found to affect the
performance of eye-hand coordination in terms of
both reaction time and movement time
• Therefore, the rehabilitation of stroke survivors
should not be confined to a stable posture such as
sitting

34. Clinical
Relevance
• Rehabilitation can be geared toward using the
trunk strategy to enhance upper limb performance
during different postural tasks.
• Conversely, restraining trunk movement might be
used to reintroduce the normal movement pattern
for reaching.

35. Limitation of the
study
• Small sample size
• Used convenience sampling
• Information about the kind of stroke or the site of the lesion
was not collected
• Stroke survivors with hemianopia or any visuospatial
neglect were excluded from this study; thus, how these
deficits affect the eye-hand coordination was not examined
• Knee proprioception assessment adopted in this study
might not be specific to the postural stability task.

36. Conclusion
• Training of eye-hand coordination in sitting and
standing are important
– Due to the poor performance in reaction and movement time
in both sitting and standing position in paretic side
• Reaching training on AP direction may be useful for
the rehabilitation of eye-hand coordination.
– Due to the high demand of postural stability
• Strengthening the elbow flexors and grip may help the
eye-hand coordination

37. CONFLICT OF INTEREST
 Authors disclose no conflict of interest
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38. Critical analysis
Strength of the study
– One of the rare study which examines the
interrelationship between eye hand coordination and
postural stability – Findings of this study helps in
‘transfer of learning’ of skills to real life situations
– Previously tested procedure has been used for the
assessment of eye hand coordination, proprioception
etc…

39. Critical analysis
‘Weakness’ of the study
• Study Hypothesis is not clearly stated
• Justification for inclusion and exclusion criteria are not
mentioned / referenced
• Correlation of reaction time, movement time and accuracy with
functional reach test is not clearly depicted in the given table
• Potential confounding variables are not addressed. Like fear of
fall etc…

40. Critical analysis
• Comments
– …in such a scenario, instead of paired ‘t’ test, Odds ratio
could have been used for the statistical analysis to find
out the association between the variables than just to
find out the mean difference between the variables
– Reaching task could have been more ‘functional’ where
the researchers can really examine a ‘contextually
relevant functional task’

41. Potential
Implications
• Training of eye-hand coordination in sitting and standing
posture can be further emphasized in our practice

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