The document outlines the rehabilitation of unilateral spatial neglect (USN), detailing its complexity, types, management strategies, and fluctuating severity after strokes. It discusses the neuroanatomical evidence linking different brain regions to various forms of neglect and presents various treatment approaches, such as prism adaptation, caloric stimulation, and transcranial magnetic stimulation. Finally, it emphasizes that effective management varies with the stage of rehabilitation, suggesting that early intervention is critical for better outcomes.

1. Rehabilitation of
Unilateral Spatial
Neglect
Phinoj K Abraham, MOTh.,
Asst. Professor,
SRM College of Occupational Therapy
Presented on : 02-08-2012
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2. Key Article
“Rehabilitation of Unilateral Spatial
Neglect: New Insights from
Magnetic Resonance Perfusion
Imaging”
Argye E Hillis., Arch Phys Med Rehabil 2006;87(12 Suppl 2):S43-9.
2

3. Overview
• Introduction & Background
• Heterogeneity(types) of Unilateral Neglect (USN)
• Management of USN
• Fluctuation in neglect severity after stroke
3

4. Introduction
• USN- often a tremendous challenge to
rehabilitation professionals
• Contributors of this challenges
1. Anosognosia (failure to recognize deficits)
2. Anosodiaphoria (Lack of concern regarding
defecits) & denile
3. Heterogeneity of the condition
4. Fluctuation in neglect severity after stroke
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5. Heterogeneity of USN
• Authors vary considerably in dividing this syndrome
• Near Vs. Far neglect
• Intentional Vs. Attentional neglect
• Visual Vs. Motor / Tactile Neglect
• Personal Vs. Peripersonal Neglect
• Viewer centered (Egocentric) Vs. Stimuli Centered
(Allocentric) neglect
• Motor Vs. Premotor Neglect
• So Much….??!!
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6. From this we can understand that…
• Unilateral neglect is a heterogeneous
syndrome with several subtypes.
• It’s possible that many distinct disorders
have been inaccurately lumped
So I Thought to
do little more
together under a single label
literature search
• It appears that impairments of several
different mechanisms converge to
result in neglect
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7. Classification
• Despite the previously mentioned limitations, we
may loosely describe unilateral neglect with four
overlapping variables:
• Type
• Range
• axis and
• orientation.
Ref: Wikipedia
But No Cross Ref..!!
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8. A. Type
Type
Disorders
of Input
Inattention
Disorders
of Output
Motor
Neglect
Pre motor
Neglect
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9. Type Contd…
• The neglect of input,
• “Attentional” or “visual-perceptual”neglect 1
• Ignoring contralesional sights, sounds, smells, or
tactile stimuli.
• Patients may have “representational neglect,”2
patients may ignore the left side of memories,
dreams, and hallucinations.
1. Neurobiology of Unilateral Neglect NEUROSCIENTIST 12(2):153–163, 2006.
2. Ste´phanie Ortigue, MS et al 2001 Ann Neurol 2001;50:401–404
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10. Type Contd…
• Output Neglect
• Motor Neglect1
• Patient does not use a contralesional limb despite the
neuromuscular ability to do so.
• Premotor /Intentional Neglect or directional
hypokinesia1
• Patient can move unaffected limbs ably in ipsilateral
space, but has difficulty directing them into
contralesional space
1. Neurobiology of Unilateral Neglect NEUROSCIENTIST 12(2):153–163, 2006.
10

11. B. Range
• Range in terms of what the patient neglects
Range
Egocentric
Allocentric
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12. C. Axis
• Most tests for neglect look for rightward or leftward
errors.
• But patients may also neglect stimuli on one side of a
horizontal or radial axis.
• For example, when asked to circle all the stars on a
printed page, they may locate targets on both the left
and right sides of the page while ignoring those
across the top or bottom.
12

13. D. Orientation
• “Left of what”
• Person
 Egocentric N
• Stimuli
 Allocentric N
13

14. Diverted…??!
Let’s go back to the main article..!!
14

15. Egocentric Vs. Allocentric Neglect
• Based on the ‘distinction between reference frame of
USN’
• Egocentric also called as viewer centered N.
• “neglect of the contraleisional side of the view of the
patient”
• Allocentric also called as Stimulus Centered N.
• “Neglect of contralesional side of each stimulus in the
view”
• Some patient can have both type of neglect together
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16. 16

17. Neuro-anatomic Evidence
• STUDY 1 - Hillis AE et, al., 2000
• Authors Concluded that
• Viewer Centered neglect
strongly associated with
Hypoperfusion and/infarct of
1. Right angular gyrus
2. Right supra marginal gyrus &
3. Right visual association cortex
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18. Neuro-anatomic Evidence Contd…
• Stimuli Centered neglect
strongly associated with
Hypoperfusion
and/infarct of
1. Superior temporal
gyrus
18
Hillis AE et,al., 2000

19. Neuro-anatomic Evidence Contd…
• STUDY 2 - Ota et al., 2001
• Left viewer centered
neglect was associated
with hypoperfusion of Rt
Viewer Centered USN
angular gyrus
• Stimulus centerd N – with
Rt superior temporal gyrus
19
Stimulus Centered USN

20. Neuro-anatomic Evidence Contd…
• STUDY 3 Corbetta & Shulman proposed that,
• spatial neglect requires damage or dysfunction of 2
separate attentional mechanisms with different
localizations:
1. a top-down, spatially specific attentional
mechanism in left or right intraparietal sulcus
(dorsal parietal), biased toward attending to space
in the opposite visual field or space defined by the
midline of the trunk and
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21. Neuro-anatomic Evidence Contd…
2) a bottom-up attentional mechanism devoted to
reshifting of attention toward a stimulus on either side
of space, located in right ventral parietal (angular gyrus
- temporoparietal junction).
• On this hypothesis, USN is more common after right
hemisphere stroke than left-hemisphere stroke,
because a single lesion can affect both mechanisms
only in the right hemisphere
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22. 22

23. Principles of Rx
• Rehabilitation for viewer-centered USN should focus on
both
1. shifting attention further to the left of the viewer
and
2. increasing the sustained attention and the size of the
viewer centered attentional window or work space.
• Rehabilitation of stimulus-centered USN should focus on
shifting attention further to the left of stimuli or
increasing the size of the stimulus centered attentional
window.
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24. Treatment of Egocentric USN
A. Rx methods to shift attention further to the
left of the viewer
1. Prism Adaptation
2. Caloric Stimulation
3. Trans cranial magnetic stimulation
4. Vibrationa Stimulation on the posterior neck
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25. 1. Prism Adaptation
25
Pisella et al. 2006

26. 2. Caloric Stimulation
• The caloric stimulation
procedure involved irrigating
the external ear canal with iced
water until subjects reported
vertigo and examiners
observed nystagmus.
• It can also induce a temporary
remission ofhemispatial neglect
26
Steven M. Miller et al 2000

27. 3. Transcranial magnetic stimulation (rTMS)
• By Kinsburne 1970
• Posited that, each hemisphere spatial attention mechanism
in each dorsal parietal cortex inhibited by the other hemisphere
• In normal brain  tendency to rightward orienting supported
by the left hemisphere.
• Right hemisphere lesions determine left neglect by
exaggerating this physiologic rightward bias.
• Left hemisphere lesions would only rarely provoke right neglect
because they release a right hemisphere attentional vector,
which is less powerful than the left one
Paolo Bartolomeo, MD 1999
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28. Theoretical frame of a possible pattern of left- and right-hemisphere
contributions to the overall neural representation of egocentric space.
28
© Oxford University Press 1999
Oliveri M et al. Brain 1999;122:1731-1739

29. 3. TMS Contd…
• Researches showed that,
• In right brain-damaged patients, left frontal
TMS (trans cranial magnetic stimulation) would
interfere with a hypothetical left frontal–right
parietal inhibition vector, with the net effect of
a right parietal disinhibition and consequent
partial restoration of left extinctions (black
arrow in the previous picture).
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30. 4. Vibration
• Vibratory stimulation of the posterior neck
muscles has also been shown to improve USN.
(Brighina F et al 2003)
• This intervention would ameliorate
egocentric,rather than allocentric, neglect
(Bottini G et al 2001)
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31. B. Rx methods to improve
sustained attention
• Pharmacological Intervention
• Noradrenergic pathway stimulating drugs like
‘guanficine’
• Need Further research in this area Argye E Hillis 2006
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33. Treatment of Allocentric USN
• By increasing the size of “Attentional window”
• In their single case study Hillis AE et al found out that
• the size of the “attentional window” for stimulus
recognition was increased by presenting large circles in
the same block of trials with small circles with leftsided or right-sided targets (gaps).
• Improved detection of left-sided targets in the small
circles (butnot in the large circles) was achieved when
large circles were presented in the same block of trials.
• It was hypothesized that this improvement was due to
increasing the size of the attentional window with the
larger circles.
Cortex. 1999 Jun;35(3):433-42.
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34. Effect of various Rehab
strategies' in the Mx of USN
• Prisam Adaptation
• rTMS
• Caloric stimulation
Vibration


+

Several days
Few Weeks
2 months – 1.5 years
• Need more research to further comment on this
point Argye E Hillis 2006
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35. 35

36. Fluctuations in Neglect
Severity after Stroke
• Cause:
• The main mechanisms underlying fluctuation
in neglect is change in blood flow
(hypoperfusion)
36

37. Management - Summery
• In Acute Stage
• Earlier (in acute stage) medical management for
increasing blood circulation is has a great
effectiveness.
• In Chronic Stage
• Prism adaptation, rTMS, caloric stimulation, and
vibrotactile stimulation may be effective in more sub
acute or chronic stages of stroke.
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38. Conclusion
• Damage or dysfunction of right angular gyrus and intraparietal
sulcus respectively lead to an abnormal shift of attention to the
right of the viewer and reduced vigilance or attentional window.
Together, these deficits cause left viewer-centered neglect.
• In contrast, damage or dysfunction of right superiortemporal
cortex seems to cause left stimulus-centered neglect.
• reperfusion therapy to improve blood perfusion to brain is likely
to have an effect only in the acute stage of stroke.
• prism adaptation, rTMS, caloric stimulation, and vibrotactile
stimulation may be effective in more subacute or chronic stages
of stroke.
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39. References
• Scientific Articles
• ARGYE E. HILLIS Rehabilitation of Unilateral Spatial Neglect: New insights from
magnetic resonance perfusion imaging Arch Phys Med Rehabil 2006;87(12 Suppl
2):S43-9
• Pisella et al., 2006 Prism adaptation in the rehabilitation of patients with visuospatial cognitive disorders Laure Curr Opin Neurol 19:000–000. 2006 Lippincott
Williams & Wilkins.
• Steven M. Miller Trung T. Ngo., Studies of caloric vestibular stimulation: implications
for the cognitive neurosciences, the clinical neurosciences and Neurophilosophy Acta
Neuropsychiatrica 2007: 19: 183–203
• ARGYE E. HILLIS Neurobiology of Unilateral Spatial Neglect NEUROSCIENTIST
12(2):153–163, 2006
• Paolo Bartolomeo, et al., ; Left unilateral neglect or Right hyperattention?
NEUROLOGY 1999;53:2023–2027
• Oliveri M et al. Theoretical frame of a possible pattern of left- and right-hemisphere
contributions to the overall neural representation of egocentric space. Brain
1999;122:1731-1739
• Hillis AE, Mordkoff JT, Caramazza A. Mechanisms of spatial attention revealed by
hemispatial neglect. Cortex. 1999 Jun;35(3):433-42.
• Web Resources
• Hemi lateral Neglect http://en.wikipedia.org/wiki/Hemispatial_neglect on 03-08-12
• Caloric reflex test http://en.wikipedia.org/wiki/Caloric_reflex_test on 03-08-12
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