Visual Neglect

SURVEY OF OPHTHALMOLOGY

VOLUME 56  NUMBER 2  MARCH–APRIL 2011

MAJOR REVIEW

Visual Neglect Following Stroke: Current Concepts
and Future Focus
Darren S.J. Ting, MBChB,1 Alex Pollock, PhD,2 Gordon N. Dutton, MD, FRCOphth,3,4,5
Fergus N. Doubal, MRCP,6 Daniel S.W. Ting, MBBS,7 Michelle Thompson, BSc (Hons),6
and Baljean Dhillon, FRCPS, FRCS, FRCOphth8
1

Victoria Infirmary, Glasgow, UK; 2Nursing, Midwifery, and Allied Health Professionals (NMAHP) Research Unit,
Glasgow Caledonian University, Glasgow, UK; 3Tennent Institute of Ophthalmology, Gartnavel General Hospital,
Glasgow, UK; 4Royal Hospital for Sick Children, Glasgow, UK; 5Department of Vision Sciences, Glasgow Caledonian
University, Glasgow, UK; 6Western General Hospital, Edinburgh, UK; 7Royal Perth Hospital, Western
Australia, Australia; and 8Princess Alexandra Eye Pavilion, Edinburgh, UK

Abstract. Visual neglect is a common, yet frequently overlooked, neurological disorder following
stroke characterized by a deficit in attention and appreciation of stimuli on the contralesional side of
the body. It has a profound functional impact on affected individuals. A assessment and management
of this condition are hindered, however, by the lack of professional awareness and clinical guidelines.
Recent evidence suggests that the underlying deficit in visual attention is due to a disrupted
internalized representation of the outer world rather than a disorder of sensory inputs. Dysfunction of
the cortical domains and white-matter tracts, as well as inter-hemispheric imbalance, have been
implicated in the various manifestations of visual neglect. Optimal diagnosis requires careful historytaking from the patient, family, and friends, in addition to clinical assessment with the line bisection
test, the star cancellation test, and the Catherine Bergego Scale. Early recognition and prompt
rehabilitation employing a multidisciplinary approach is desirable. Although no treatment has been
definitively shown to be of benefit, those with promise include prism adaptation, visual scanning
therapy, and virtual reality--based techniques. Further high quality research to seek optimum shortand long-term rehabilitative strategies for visual neglect is required. (Surv Ophthalmol 56:114--134,
2011. Ó 2011 Elsevier Inc. All rights reserved.)
Key words. assessment  dorsal stream  neglect  rehabilitation
stroke  unilateral neglect  ventral stream  visual neglect

I. Introduction



spatial representation

functioning and stroke rehabilitation outcome is
well established.
Stroke, whether ischemic or hemorrhagic, is a debilitating and disabling condition that can impair
cognition, visuospatial, language, and motor function.36 Motor rehabilitation following stroke is well
recognized, but rehabilitation for visual neglect,
a common and dramatic consequence of stroke,105

Visual neglect (VN) is a neurological disorder
characterized by a deficit in attention to stimuli
on one side of the body, almost invariably contralateral to the side of the cerebral lesion.95 The
term has been used loosely and interchangeably
with hemispatial neglect, unilateral neglect, and
visual inattention. Its adverse impact on day-to-day
114
Ó 2011 by Elsevier Inc.
All rights reserved.

0039-6257/$ - see front matter
doi:10.1016/j.survophthal.2010.08.001

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VISUAL NEGLECT FOLLOWING STROKE

has received limited attention, as it can be difficult to
identify, and there is currently no consensus concerning optimal assessment and treatment of this
condition.

II. Epidemiology
141

A US study
of 1,281 stroke patients reported
a prevalence rate of VN of 43% and 20% following
right and left hemispheric stroke, respectively. This
asymmetry in prevalence of VN is consistent with
other literature4,13,21 and probably occurs because
the right hemisphere tends to allocate attention to
both hemispaces, but the left hemisphere accords
attention more selectively to right hemispace.66,116
Also, VN patients with right hemispheric stroke
generally have a worse prognosis than those with left
hemispheric stroke.13,46,131
Despite the high prevalence rate, 61% of patients
with VN were overlooked during hospital admission
in the US,40 and only 13% of stroke patients were
assessed with standardized neglect assessments in
a Canadian study.114 This low detection rate could
be explained by insufficient awareness of this
condition or may reflect inherent difficulties in
diagnosing neglect in the presence of other more
acute and readily recognizable features of stroke like
dysphagia, dysphasia, hemianopia, or hemiplegia.
In the UK, the documented prevalence rates of
VN post-stroke vary between 8%164 and 82%162 as
a result of heterogeneous patient cohorts, inconsistent definition, non-standardized assessment
methods, and different timings of the assessment.
Increased age has also been shown to be
associated with a higher incidence and severity of
VN.57,141 This could be attributed to prior cerebral
atrophy or a physiologically dampened reaction
time in the elderly population during visual searching activities, especially when intensive visual attention is required.57,102 Other demographic factors
like sex111,141 and handedness141 have no significant
influence on the occurrence of VN.

III. Varieties of Neglect
A wide range of neglect variants have been
described as a consequence of the discrepant
classifications adopted. Conceptually, it can be
considered under the following headings.169
A. MODALITY (INPUT/OUTPUT)

Neglect can be divided into sensory (input) and
premotor (output) neglect. Sensory neglect is
characterized by unawareness of sensory stimuli of
different modalities—including tactile/somatosen-

sory, auditory, and visual or visuospatial in contralesional hemispace. Premotor neglect is described as
failure to orientate the limbs towards contralesional
hemispace despite awareness of the stimulus. VN
has been primarily considered part of the spectrum
of sensory neglect; recent studies, however, suggest
that the underlying deficit primarily is a disrupted
internal computation of the spatial representation
of the external world rather than a true sensory
deficit (see section V. Pathophysiology in this
review) This has important implications in formulating optimal assessment and rehabilitation
strategies.
B. SPATIAL REPRESENTATION

Spatial representation, which depends on the
frame of reference, has also been used to distinguish
between different neglect subtypes, namely, egocentric (viewer-centered) VN and allocentric (stimulus
or object-centered) VN. Egocentric VN is described as
failure to orientate or attend to the stimuli on the
contralesional hemispace with respect to the midsagittal plane of the body, head and eye. In contrast,
allocentric VN refers to the inability to attend to the
one side of the stimulus irrespective of the relative
position of the stimulus with respect to the viewer.
Egocentric VN has a higher reported incidence
than allocentric VN as a sequel to a cerebrovascular
event. As a result, the terms ‘‘visual neglect’’ or
‘‘unilateral neglect’’ primarily refer clinically to
egocentric VN; however, these neglect subtypes exist
as separate entities with distinct neural bases58,109,113
(see section V.E Clinico-anatomical correlations of
visual neglect, herein). VN is a heterogeneous
disorder that involves various neurocognitive regions, and broader consideration needs to be taken
for each neglect subtype.
C. RANGE OF SPACE

According to the classification by ‘‘range of
space’’, VN can be divided into personal, peripersonal, and extrapersonal neglect. This classification
has been widely adopted as part of VN assessment of
the functional performance in clinical practice.

IV. Functional Impact
VN results in a range of functional impairments,
with severe neglect being associated with a poor
prognosis.79,163 Those with left VN fail to attend to
their left side, with features ranging from those
affecting personal, through peripersonal, to extrapersonal space (Table 1). Each subtype of neglect
may either manifest as a separate entity or be
associated with other subtypes. For instance, a

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Surv Ophthalmol 56 (2) March--April 2011

TING ET AL
TABLE 1

Definitions and Examples of Personal, Peripersonal, and Extrapersonal Neglect
Personal space—the space occupied by one’s body
 combing, grooming, shaving, recognizing the right half of the body only17,90 and anosagnosia (a feature in which
the patient is unable to recognize his or her own deficit)14,18
Peripersonal space—the space surrounding one’s body, within arm’s reach
 eating food from the right half of the plate and neglecting the food on the left, reading the right half of the two pages of
an open book28
Extrapersonal space—the space surrounding one’s body, beyond arm’s reach
 failing to identify meaningful stimuli and people on the left, colliding into objects on the left while mobilizing or
using a wheelchair138

patient affected by peripersonal neglect does not
necessarily also manifest extrapersonal neglect.59,173
It is important, however, to recognize that this
classification concerns the external observers’ interpretation rather than the nature of the disturbance of the internalized, virtual representation of
the external world that characterizes human vision/
visuospatial perception. Also, VN may be associated
with other forms of neglect, including tactile,
auditory, and motor neglect.

V. Pathophysiology
VN is a multifaceted disorder. The anatomical,
physiological, and conceptual models of cortical
visual processing have always been highly contentious scientific issues. As mentioned, VN can be
conceptually divided into several categories according to the modality (input/output), the spatial
representation, and the range of space. Although
various mechanisms and models have been proposed and examined, none has fully and successfully
captured the entire spectrum of this heterogeneous
disorder. We attempt a systematic overview of
pathophysiology and clinico-anatomical correlations
of VN from different perspectives.
A. PHYSIOLOGY OF VISUOSPATIAL PERCEPTION

It is becoming increasingly apparent that our
brain operates and processes visual information via
two distinct, but complementary, higher neural
processing pathways, namely, the dorsal stream
and ventral stream (as proposed by Milner and
Goodale).56,119,120 They suggested that the dorsal
stream, which connects the visual cortex with the
superior parietal lobe and the intraparietal sulcus,
subconsciously assimilates incoming visual information in order to bring about immediate ‘‘on-line’’,
visually guided movements through the virtual
images in the mind, which constitute an internal
and subconscious egocentric spatial representation
of the multidimensional external world. By contrast,
the ventral stream, which bridges the visual cortex

and the inferior temporal lobe, is accountable for
our conscious, object-based visual perception and
recognition. Dysfunction of dorsal stream results in
optic ataxia (impaired visual guidance of movement), and dysfunction of ventral stream causes
visual agnosia (impaired recognition of visual
stimuli), respectively. Although this model provides
a comprehensive explanation for various components of visuospatial perception and visuomotor
function, the manifestation of VN, which normally
follows the damage of inferior parietal lobe, has yet
to be fully considered in the context of this dorsal-ventral dichotomy.156 Also, the double dissociation
between VN and optic ataxia or visual agnosia has
suggested separate underlying disorders of the
neural substrates.73,133
Instead of the occipito-parietal and occipitotemporal pathways, the dorsal--ventral dichotomy
variant proposed by Corbetta and Shulman32
focused on the attentional basis of the frontoparietal networks, namely, the dorsal and ventral
frontoparietal pathways. The bilateral ‘‘dorsal’’
pathways, which connect the superior parietal lobes
and the intraparietal sulci with the dorsal frontal
lobes, including the frontal eye fields, are involved
in goal-directed, top--down attentional selection.32
This top--down attention facilitates visuospatial
exploration in the context of prior knowledge of
what to search for or what the task is.33 In contrast,
the right lateralized ‘‘ventral’’ pathway, which links
the temporal parietal junction (TPJ), inferior
parietal lobe (IPL), and ventral frontal lobe, is
associated with stimulus-driven, bottom--up attentional selection.32 This bottom--up attention simply
refers to the ability to capture an event occurring in
the surrounding world—salience detection.33 In
view of the overlap between the neural basis of VN
and their proposed ‘‘ventral’’ network, Corbetta and
Shulman infer that VN is associated with a bottom-up attentional deficit.32 Also, their proposed right
lateralized ventral pathway helps explain the higher
incidence of VN following right posterior parietal
damage.

VISUAL NEGLECT FOLLOWING STROKE

In addition, consistent activation of both frontal
and parietal regions, as evident from imaging
studies,52,134,157 during tasks requiring spatial attention and visuomotor function have supported the
neural basis of this fronto-parietal model. Nonetheless, there is emerging evidence showing that
patients with VN may exhibit deficits of both
attentional components, including sustaining attention (goal-directed)24,74 and salience detection
(stimulus-driven),23,33 which suggests that a combination of both of the described conceptual frameworks is required to explain this complex disorder.
B. SPATIALLY LATERALIZED DYSFUNCTION OF
VISUAL NEGLECT

According to the original definition, VN is
a disorder characterized by the failure of orientating
or attending towards the stimuli on one side of the
hemispace; it is a form of spatially lateralized
dysfunction. For instance, patients with ‘‘egocentric’’
VN can exhibit complete inattention (perceptual/
input neglect) or impaired visuospatial exploration
(premotor/output neglect) confined to contralesional hemispace, with normal visuospatial perception within ipsilesional hemispace. This spatially
lateralized dysfunction of VN has been well demonstrated by both clinical observation and the VN
assessment tools (see subsequent discussion).
Heilman et al66 hypothesized that the right
posterior parietal cortex, which is highly specialized
for spatial attention, allocates attention to both
hemispaces, whereas the left posterior parietal cortex
allocates attention, more selectively, to the right
hemispace. This explains why VN is more commonly
reported following right rather than left hemispheric
damage.13,21,141 This is also why the affected individual exhibits deficits on the contralesional side as
well as the ipsilesional side, to a milder extent,12,149
when the right hemisphere is affected. Moreover, the
common paradoxical observation of contralesional
limb apraxia (inability to activate limb) following left
IPL damage, but the development of VN following
right IPL damage, underlines the organizational and
functional asymmetry between both IPLs, at least in
the context of spatial attention.54
On the other hand, Kinsbourne96 suggested that
allocation of spatial attention towards both hemispaces is balanced by the reciprocal inhibition from
each hemisphere, with left hemisphere allocating
attention towards the right hemispace and vice
versa. Therefore, when there is a right hemispheric
damage, the unopposed left hemisphere becomes
relatively hyper-attentive towards the right hemispace, subsequently leading to left VN. This model is
further reinforced by Koch et al100 that describes

117

relative electroencephalographic hyperexcitability
in the left posterior parietal cortex (PPC) of the
neglect patients with right hemispheric stroke,
resulting in rightward attention bias (or left visual
neglect). Improvement of VN was observed in 7 of
10 patients following the application of repetitive
transcranial magnetic stimulation (r-TMS) over the
unaffected PPC. In a similar vein, Oliver et al128
reported beneficial effect in patients with VN
following the application of r-TMS on the unaffected PPC. An explanatory mechanism is that
r-TMS disrupts the integrated neural activity of the
intact side, dampening the attention to the ipsilesional side, and thereby restoring the orientation
balance between both hemispheres.
C. NON-SPATIALLY LATERALIZED DYSFUNCTION
OF VISUAL NEGLECT

Until recently, VN was thought strictly to be
attributable to lateralized disruption of the spatial
attention on one side of the visual space; however,
there is emerging evidence proposing that VN is not
necessarily confined to one hemispace. It can
comprise both spatially lateralized and non--spatially
lateralized dysfunctions.74 In other words, patients
with VN may completely neglect the contralesional
hemispace (spatially lateralized) while demonstrating global inattention to stimuli regardless of the
location of the target (non-spatially lateralized).
Both the IPL and the ventral frontal region—
which, when damaged, are frequently associated
with VN—have been shown to exhibit functions
related to non-spatial attention including sustained
attention and salience detection.74 Similarly, VN
patients, with damage to the IPL, may demonstrate
these non-spatial attentional deficits. This can be
assessed by techniques including the oddball paradigm,31,38 which requires the patient to detect target
stimuli interspersed with non-target stimuli at the
same area, and attentional blink paradigm,75 a measure that assesses the ability of salience detection
and perception of each stimulus among a series of
rapidly changing stimuli at one spatial location. A
delayed ‘‘attentional-blink’’ response is suggestive of
an attentional deficit. Although non-spatial inattention may be doubly dissociable from VN,150 the
presence of a non-spatial attentional deficit aggravates the severity of VN.75
These intriguing findings enhance understanding
of the pathophysiology of VN and, more importantly, facilitate the development of potentially more
effective therapies including sustained attention
measures and pharmacological intervention directed towards improving general non-spatial
attention.107

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D. ROLE OF NON-VISUAL AFFERENT INPUTS

In addition to visual afferent input, egocentric
multidimensional internalized spatial mapping requires multiple afferent inputs from non-visual
receptors, including neck muscle19 and extraocular muscle proprioceptors,75 and the tactile
and the vestibular systems.125,127 This afferent proprioceptive feedback maintains the required stability and perception of the location of the visual
images by maintaining correct egocentric localization of the body despite head and eye movement.
There is evidence that patients who have altered
extraocular muscle proprioception175—either from
surgery,25,161 forced ductions with a suction contact
lens,48 or dysfunction of the trigeminal nerve26,171—
demonstrate errors in spatial localization and
visually guided movement.
Karnath87 demonstrated the role of neck muscle
proprioception in maintaining egocentric spatial
localization. He observed that the ipsilesional deviation of neglect patients when looking straight
ahead can be ameliorated by the application
of vibration to the contralesional neck,87,152 modifying the afferent input from the neck muscle
proprioceptors.
In addition, the role of the vestibular system in
body orientation and egocentric spatial localization
has long been recognized. The vestibular input
contributes to spatial orientation mainly via the
vestibulo-ocular reflex, which involves the transmission of afferent inputs from the vestibular nuclei
to the ocular motor nuclei and higher cortical
centers via the medial longitudinal fasciculus.125,127
Following integration of the afferent inputs in the
higher cortical centers, efferent outputs are transmitted along vestibulospinal projections for head,
eye, and body orientation—the internal ‘‘plumb
line,’’ which accords balance and our knowledge of
the vertical, and hence, spatial localization.125,127
This concept has been further reinforced by the use
of vestibular caloric stimulation (irrigation of the
ear canal with either warm water ipsilaterally or cold
water contralaterally), which transiently reduces the
orientation bias in VN and can restore the egocentric spatial reference frame.88,147 Longer term
interventions, designed to ‘‘deceive’’ the sensory
input of the visuospatial perception rather than
addressing the underlying lack of awareness, remains elusive.
E. CLINICO-ANATOMICAL CORRELATIONS OF
VISUAL NEGLECT

Several factors challenge clinicians and researchers
investigating the neural basis of VN. First, patients
with VN often manifest extensive brain damage, which

TING ET AL

hinders precise anatomical correlation. Second, pure
assessment of VN is problematic in the stroke patient
who has co-existing cognitive impairment, causing
difficulty in recruiting ‘‘ideal’’ VN patients for further
investigation. Also, the lack of detailed classification of
the different neglect subtypes can lead to overgeneralization of the neural basis of VN. For example,
the distinction between egocentric VN and allocentric
VN, which can occur independently,58,109 has not
been made in many studies.
Various cortical regions serving visuospatial attention have been identified by high quality functional
brain imaging like functional magnetic resonance
imaging and positron emission tomography. These
regions comprise, in particular, the inferior parietal
lobe and the TPJ,64,70,123,170 the superior temporal
gyrus,85 and the frontal lobe, including the medial
and inferior frontal gyri.75,76 In contrast, the previously controversial role of the subcortical regions
implicated in VN has been refuted by recent studies,
suggesting that, instead of the subcortical infarction
itself, VN is associated with hypoperfusion of the
overlying cortex and that subcortical infarction
alone does not result in VN.70
The neuroanatomical findings can be influenced
by the timing of assessment. For instance, Mort et
al,123 who investigated the neural basis of VN during
the chronic phase (63 days post-stroke), have
reported that VN is most strongly associated with
angular gyrus (part of the inferior parietal lobe)
infarction. In contrast, Karnath et al84 examined
their patients at 8 days post-stroke and had observed
the superior temporal gyrus is the most common
implicated region in VN.
Moreover, the development of diffusion tensor
imaging, which provides the facility to track whitematter tracts, has led to a quantum leap in the
understanding of the neuro-anatomical correlation
of VN. Various white-matter tracts have been
identified, particularly in the fronto-parietal network,11,15,37 and their dysfunction can lead to the
‘‘disconnection syndrome’’ underlying VN.11,37 This
observation is in accordance with the anatomical
and theoretical model proposed by Corbetta and
Shulman,32 who focused on the attentional basis of
the fronto-parietal network. This suggests that
spatial attention operates in a multi-level network
that requires intact neurocognitive cortical regions
and the underlying connections between them.
Interestingly, VN results from both anterior and
posterior circulation strokes, depending on the
affected corresponding white-matter tracts.15,37
In addition, VN has been classified according to
the site of neuroanatomical damage, which chiefly
comprises three areas: the parietal lobes, the frontal
eye fields, and the cingulate regions.117 Each of the

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VISUAL NEGLECT FOLLOWING STROKE
TABLE 2

Summary of Neuroanatomical Classification and the Functional Consequences of VN
Type

Function of Each Area

Presentation

Parietal neglect

The posterior parietal lobes integrate afferent
stimuli of any modality including visual
stimuli, transforming external space into an
internalized representation

Frontal neglect

The frontal eye fields interact with the
parietal lobes in selecting salient
information and filtering irrelevant
information, thus planning meaningful
visually guided movement

Cingulate neglect

Provides limbic integration, responsible for
allocating directed attention according to
motivation130

Loss of subconscious synthesis of the
internalized representational space,
resulting in unawareness of the visual
stimuli in contralesional hemispace, even
one’s own body (a form of anosagnosia)
Failure of limb orientation towards
contralesional hemispace in the absence of
hemiparesis, even when using the
unaffected limb on the ipsilesional side,
which suggests the abnormality lies in
motor output instead of sensory input;34,65
this is probably secondary to a defect in the
internalized representation of motor
programming towards the contralesional
side
Spends a disproportionately long period
attending to the greater motivational event,
omitting the others which have less impact

Data from Mesulam et al.117

neuro-anatomical neglect subtypes exhibits some
degree of site-specific variation (Table 2). Although
this classification provides useful insights into the
complex neuroanatomical correlation of VN, it does
not include the underlying complex disorders of
function. Also, the differentiation of these subtypes
can be difficult in clinical practice.
As discussed earlier, spatial representation takes
into account different frames of reference, primarily
viewer-centered (egocentric) and stimulus-centered
(allocentric). Hillis et al70 examined the neural basis
of VN subtypes and observed distinct physiology and
neural correlates underlying both subtypes with the
aid of high quality functional brain imaging. They
have reported that egocentric VN primarily follows
damage to the inferior parietal lobe69,70 and, to some
extent, the posterior inferior frontal gyrus,70 which
are implicated in the ventral frontoparietal network
proposed by Corbetta and Shulman.32 Similar association between egocentric VN and dysfunction of the
supramarginal gyrus (part of the inferior parietal
lobe) has been observed by Medina et al.113 On the
other hand, allocentric VN is more commonly
observed following injuries to the temporal regions,
including the superior temporal gyrus,70 the ventromedial temporal area,58 and the posterior inferior
temporal gyrus.113 This is consistent with Milner
and Goodale’s proposal that the temporal or
ventral pathway is highly accountable for objectbased perception and recognition; therefore, dysfunction of this pathway leads to allocentric VN. The
functional differences and the interactions among
various intra-temporal regions have yet to be further
investigated.

Although the neural correlates of left VN have been
well studied, right VN following left hemispheric
stroke has received limited attention. Kleinman et
al98 focused on the neural correlates of VN subtypes
following left, instead of right, hemispheric stroke
and reported a higher proportion of allocentric VN
than egocentric VN, which contrasts with the findings
of Hillis et al.70 These findings, once again, suggest
that both hemispheres are organized and function in
distinct ways in the context of spatial attention.
In view of the heterogeneity of VN, we emphasize
that all studies should be interpreted with caution
because they are influenced by the type of VN
included in the study, the assessment methods used,
and the timing and type of brain imaging instituted.
F. CLINICAL SYNDROMES ASSOCIATED WITH
VISUAL NEGLECT

VN has been found to be associated with other
complex parietal lobe syndromes that affect visuospatial comprehension and attention, such as
Gerstmann and Balint syndromes. Gerstmann syndrome results from a focal lesion affecting the
angular and supramarginal gyri near the TPJ,
usually on the left, and is characterized by inability
to perceive an object properly (agnosia), dysgraphia, dyscalculia, and left--right disorientation.132
Balint syndrome, first reported in the early 20th
century,9 is an uncommon disorder that classically
results from bilateral posterior parietal pathology and
comprises a constellation of symptoms: unilateral
visuospatial inattention (left hemineglect), deficits in
visually guided movement despite normal limb

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Surv Ophthalmol 56 (2) March--April 2011

strength (optic ataxia), and the inability to shift gaze
voluntarily to objects of interest despite normal eye
movements (ocular apraxia).9,63 The spatial disorder
of attention emphasized by Balint was further
regarded as ‘‘disturbance of visual orientation’’ by
Holmes71 and simultanagnosia by Wolpert.177 Based
on his observation of six soldiers with bilateral
parietal-occipital lobe injury particularly affecting
the angular gyri, Holmes concluded that damage to
the angular gyri can lead to what he called a ‘‘disturbance of visual orientation’’71 and results in difficulties in precise determination of the multidimensional
position of an object or relative positions of objects
(optic ataxia) and in learning the new surroundings
and in transferring attention from one object to
another (ocular apraxia). On the other hand, the
term ‘‘simultanagnosia’’, coined by Wolpert,177 refers
to the inability to perceive and integrate all the
components of a visual scene. Each element of Balint
syndrome—left hemineglect, optic ataxia, and ocular
apraxia—may manifest independently.34
Refer to Rizzo and Vecera’s142 study for further
elaboration.

VI. Assessment of Visual Neglect
A. CURRENT CLINICAL GUIDELINES

Recommendations concerning the specific assessment methods of VN remain limited. US39 and
UK77,154 guidelines consistently recommend that
visuo-perceptual function, including the potential
for VN, should be assessed in patients in stroke units
employing a multidisciplinary approach. MiniMental State Examination and Addenbrooke’s
Cognitive Examination (2005) are the two most
well-recognized general cognitive assessment batteries in current clinical practice in the UK.47,121 The
limitation of both tests is that VN is only assessed by
drawing and copying objects (Table 3).
No specific assessment tool is recommended in
the US. On the other hand, the UK guidelines77
recommend the use of Behavioral Inattention Test
whereas the Canadian27 guidelines recommend the
use of specific assessment tools for VN, comprising
the Comb and Razor Test, the Line Bisection Test
(LBT), and the Behavioral Inattention Test with the
alternatives of the Rivermead, Ontario Society of
Occupational Therapy Perceptual Evaluation and
the Motor Free Visual Perceptual Test.
B. HOW IS VISUAL NEGLECT ASSESSED?

The results of an extensive literature search
concerning the assessment of VN and the underlying
rationale, assessment profiles, with strengths and
weaknesses of the more common tests of VN are

TING ET AL

summarized in Table 3. The assessment methods
comprise four main groups: pencil-and-paper tests,
behavioral assessment, clinical observation, and more
recent techniques.
1. Pencil-and-paper Tests
VN can be sought by the cancellation test, the
LBT, and the copying and drawing test.144
The cancellation task (Fig. 1) requires the patient
to delete multiple identical visual target symbols on
a paper sheet. Incomplete or disproportionate deletion on one side indicates VN. There is robust
evidence showing that this type of test, particularly
interspersed with distracters, has the best sensitivity of
the pencil-and-paper tests.60,61,97,110 Common variants include the star cancellation test, the letter
cancellation test, and the bell cancellation test.
Moreover, structured observation of cancellation test
performance, taking into account the location of the
initial commencing point2 (deemed to be the most
sensitive measure) along with the scanning pattern,
the search time, and the number of re-cancellations
of the same target,55,108,167 provide useful qualitative
information in addition to quantitative scores.
The LBT (Fig. 1) requires the patient to estimate
and bisect the midline, thereby determining leftward/rightward orientation bias. Despite limitations,
the construct validity,110 reasonable sensitivity and
reliability, and ease of administration render this
a good supplementary pencil-and-paper test.8 The
minimal time required for administration is a major
advantage for clinicians.
On the other hand, copying and drawing tasks
(Fig. 1) are the least satisfactory pencil-and-paper
tests in terms of sensitivity, reliability, and validity,8
but have a place in gaining an understanding of the
nature of the morbidity.
Lindell et al104 and Jehkonen et al80 have
highlighted the benefit of combining several tools
in yielding a higher detection rate and better
characterization of VN. On the basis of the available
evidence, the star cancellation test, coupled with the
line bisection test, are recommended as screening
tools for all patients with hemispheric stroke.
2. Behavioral Assessment Tools
Azuovi et al found that behavioral assessment has
a much higher sensitivity than pencil-and-paper tests
(96% vs 65%).5 This finding is in accordance with
other similar studies.6,61 Therefore, behavioral
assessment is essential to enhance VN detection
rate and, more importantly, to determine and
evaluate the nature and level of functioning.4
The BIT and the Catherine Bergego Scale (CBS)
are two of the most frequently used tests. The BIT176 is

Synthesis of Various Types of Assessment of VN
Tests
Cancellation

Brief Description/Rationale
Patient is asked to cross out the visual targets on a paper sheet
Looking for disproportionate omission of visual targets on one
side of hemispace

Line Bisection Required to estimate and bisect the middle of straight lines
Deviation towards the ipsilesional side suggests orientation bias
and, hence, potential visual neglect

Strength

Limitation
60

a

Star cancellation has the best sensitivity (76.4% to
100%110) among the three forms of pencil-andpaper tests
Good construct validity110
Greater reliability than line bisection test110
Qualitative interpretation enhances the detection
rate55,108,167

Refer to

Easy to administer
Good validity
Reasonable sensitivity115 (60%43 to 76.4%8)
Comparable reliability to cancellation test
May help distinguish between motor and sensory
neglect with modification of test

False positive results may be
produced secondary to hemianopia/handedness43
Sometimes non-standardized
Difficult to interpret the result
Refer toa

Drawing and Required to draw and copy objects
Assesses for representational neglect, which may
copying task Leaving out one side of the given object or cramming everything
suggest the presence of orientation bias and
in one side of the figure is suggestive of VN
potentially, VN

VISUAL NEGLECT FOLLOWING STROKE

TABLE 3

Poor sensitivity and validity8
Interpretation of outcome limited by subjectivity and other
cognitive impairment
Refer toa

Comb and
Razor test

Asked to comb hair and shave
Looking for omission of one side of the face

Good supplementary test for behavioral inattention as Only assesses personal space
it assesses attention for personal space
May be confounded by other
stroke conditions (e.g.,
hemiparesis)

Behavioral
Inattention
test62

Consists of six pencil-and-paper tests and nine behavioral subtests Assesses functional performance
Provides quantitative and objective assessment
Good predictive measure of functional performance
in daily living62,115

Does not evaluate personal
space
Time consuming

Catherine
Bergego
Scale5

A checklist of 10 items that assess normal functioning in daily
living

Scoring of the outcome does
not differentiate the neglect
subtypes

Clinical
observation

Continuous observation during the delivery of care, looking for Allows continuous assessment of VN, which might be Does not provide quantitative
and objective assessment
signs indicative of VN, for instance, eating food from one side
missed earlier on
of the plate, colliding repetitively with obstacles on the same Improves the detection and assessment of VN when Cannot differentiate between
motor neglect and VN
side
used as a supplementary method to clinical VN
Non-standardized
tests81,164

Assesses all three conceptual spaces including the
functional performance in daily living
Assesses patient’s self awareness of own deficit
(anosagnosia score)7
Good validity, reliability and sensitivity5,115

(continued on next page)
121

These investigations only evaluate attention for peripersonal space and cannot differentiate between input and output neglect.
This table is modified from Plummer et al.137

Focuses on peripersonal space
Visuospatial perception in the
virtual environment may vary
between individuals78
Further evaluation of validity,
sensitivity, and reliability is
required
a

Oculography

Tests

Allows assessment in a simulated environment reVirtual reality Requires a set of hardware (i.e., head-mounted display), eye
lating to daily life
trackers, and head-position sensor
Creates a more interactive, versatile and safer
Enables the users to explore real-time virtual images while
relevant information including head motion, scanning pattern,
environment for assessment of VN
Presence of eye trackers aid the assessor to record
and spatial orientation are recorded and analyzed
patient’s visual search pattern and develop better
understanding of the nature of VN

Requires the patient to focus at the midpoint of a given object,
image or task
Looking for orientation bias towards the ipsilesional side which
indicates VN

Allows pure assessment of VN as manual exploration There is no robust evidence on
is not required, which thus excludes the motor
the validity, sensitivity, and
component/premotor neglect
reliability of this test
Does not assess personal space

Surv Ophthalmol 56 (2) March--April 2011

30

Brief Description/Rationale

Table 3 (continued )

Strength

Limitation

122

TING ET AL

a 15-item checklist, which comprises six conventional
tests (line crossing, letter cancellation, star cancellation, figure copying, line bisection, and free drawing)
and nine behavioral tests (picture scanning, telephone dialing, menu reading, article reading, telling
and setting the time, coin sorting, address and
sentence copying, map navigation, and card sorting).
There is consistent evidence showing that BIT serves
as a good predictive measure of functional performance in daily living.62,115 The major limitation of
this battery is that it does not formally assess the
personal space. This is imperative because each of the
neglect subtypes (personal, peripersonal, and extrapersonal) can manifest as a separate entity.
On the other hand, the CBS7 is a 10-item checklist
that focuses on functional performance of activities
of daily living. These include grooming and shaving
the left part of the face, wearing the left sleeve or
slipper, eating food on the left side of the plate,
cleaning the left side of the mouth after eating,
spontaneous leftward gaze, ‘‘knowledge’’ of the left
part of the body, auditory attention to stimuli from
the left, collisions with objects on the left, leftward
navigation in familiar places, and locating familiar
items on the left. Although this test was originally
designed for the assessment of left VN, it should be
applicable to right VN. We prefer CBS over BIT
because CBS considers all three conceptual spaces,
includes anosognosia scoring,7 and has fine psychometric properties, including validity, sensitivity, and
reliability.5,115 Anosognosia scoring serves as an
important indicator of VN severity.51,137
We recommend that all patients who demonstrate
spatial orientation bias on VN screening test should
undergo some form of behavioral assessment like
BIT or, preferably, CBS.
3. Clinical Observation and History-taking from
the Patient and the Near Contacts
Skilled clinical observation should increase the
detection rate of VN,81 which may be missed
because of the false negative result of the standardized tests and VN’s inherently subtle and fluctuating
course.2 Family and friends who are familiar with
a patient’s normal behavior may also play a significant role in picking up subtle neglect behavior. VN
may be missed during the acute phase of stroke but
may be picked up later by other allied health
professionals or at home by the near contacts.
4. Recent Development of Assessment
Technique
One of the main shortcomings of the pencil-andpaper tests is the inability to differentiate between
sensory/input and premotor/output neglect, as

VISUAL NEGLECT FOLLOWING STROKE

123

Fig. 1. Examples of patient with VN neglecting the stimuli on the left hemispace in: (A) a cancellation task; (B) a line
bisection task; and (C) a copying and drawing task. (Adapted from http://ahsmail.uwaterloo.ca/waktse/assessment.
html.)

these tests require both visual attention and manual
exploration. Chiba et al30 have proposed the use of
oculography for the midpoint-fixation task, which
removes the manual component.
Virtual reality (VR) based techniques may potentially overcome the shortcomings of traditional
assessment methods.94 The use of VR systems not
only helps to establish a better assessment and
understanding of the nature of VN, but also creates
a safe, versatile, and multimodal virtual environment to assess the patient’s functional performance
in a range of daily living tasks. Conventional tests
including the line bisection test, the cancellation
test, and daily living tasks have all been incorporated into a VR system.166 However, the VR
assessment focuses on use of peripersonal and, to
a certain extent, extrapersonal space and further
evaluation is required to determine its sensitivity,
cost-effectiveness, and practicability.
C. DISTINCTION BETWEEN VISUAL NEGLECT
AND OTHER VISUAL PROBLEMS

VN is commonly associated with other visual
problems, including visual extinction and homony-

mous hemianopia (HH). Therefore, understanding
of the nature of these visual problems and the
distinct features of each visual condition should
facilitate assessment and diagnostic process.
Visual extinction is described as the failure of
identifying one of two simultaneous stimuli, while
retaining the perception of a stimulus presented
singly in either hemispace.169 Unlike VN, the
allocation of attention in the context of visual
extinction is largely task-dependent.172 For instance,
the ability to localize stimuli on bilateral display can be
markedly impaired (similar to neglect), but with
retained normal reporting of numerical stimuli on
bilateral presentation.172 Extinction may also occur
when both stimuli are presented simultaneously
within the same hemifield.172 Nonetheless, visual
extinction has been described as a cardinal sign
indicative of a deficit in attention,16,139 or as part of
neglect disorder.67 Clinically, visual extinction should
be sought during neurological examination, as visual
extinction and neglect are commonly, but not invariably, associated.49 This can be done by asking the
patient to point to the examiner’s moving finger,
initially one side at a time and then bilaterally in mirror

124

Surv Ophthalmol 56 (2) March--April 2011

image quadrants. The ability to identify a single
stimulus, but not simultaneous stimuli, defines extinction. In addition, Hillis et al68 have shown that visual,
tactile, and motor extinction involve mainly the visual
association cortex, the inferior parietal lobe, and the
superior temporal gyrus, respectively. These anatomical findings, which considerably overlap with the
neural underpinnings of VN, help explain the
frequent co-occurrence of both VN and extinction.
Involvement of ophthalmologists and orthoptists
is of potential value, as ‘‘egocentric’’ visual neglect
may occasionally coexist with, or masquerade as,
a visual field defect,101 despite their distinct pathophysiology. Egocentric VN is characterized by inattention toward the contralesional hemispace,
which is independent of the direction of gaze,
whereas HH is the actual loss of visual field of
contralesional hemispace, which can be compensated by the head and eye movements. Scanning
behavior, which relies on spatial attention, serves as
the primary distinguishing factor. Patients with VN
can have profound difficulties in surveying and
navigating the visual scene in affected hemispace
and cannot consciously compensate for within the
neglected hemispace. In contrast, HH poses a less
significant impact on the affected individual’s
scanning behavior because spatial attention of one
side of the visuospatial world is retained, thereby
allowing compensatory movement of the eye, head,
and body towards the affected visual field. Therefore, behavioral assessment can be very useful in
differentiating these two disorders.
In addition, VN, but not HH, is commonly
associated with visual extinction.49 Also, other
modalities such as somatosensory, auditory, and
motor neglect may coexist with VN, whereas HH is
strictly a visual deficit. Visual evoked potentials
(VEPs) are increasingly used to differentiate VN
and HH. Patients with VN usually have a near
normal response on VEPs,160 whereas patients with
HH commonly demonstrate marked disparity between the normal and affected hemifields.90 In
addition, various alternative methods have been
proposed to distinguish these conditions93 (Table
4). Such differentiation may be difficult, as they may
overlap or be compounded by a condition called
hemianopia anosognosia, which is characterized by
unawareness of the visual field loss.18,29
D. SUMMARY AND RECOMMENDATIONS FOR THE
ASSESSMENT OF VISUAL NEGLECT

Despite a lack of consensus regarding neglect
assessment, we recommend that health professionals
routinely assess for personal, peripersonal, and
extrapersonal neglect, and, more importantly, the

TING ET AL

level of independence in activities of daily living. We
recommend that the star cancellation test and the
line bisection test should form part of the routine
cognitive assessment battery. This approach is best
coupled with the Catherine Bergego Scale and
continuous clinical observation via multidisciplinary
teamwork. Application of virtual reality--based assessment may be of potential value in future practice.
In addition, it is imperative to distinguish VN from
other visual problems, especially homonymous
hemianopia.

VII. Rehabilitation of Visual Neglect
There is an extensive body of literature concerning the effectiveness of the rehabilitation of VN. In
order to minimize the selection bias and enhance
the level of evidence, we have, therefore, centered
analysis on high-quality literature such as systematic
reviews and randomized controlled trials. Relevant
evidence3,20,50,82,103,106,136,140 regarding the effectiveness of rehabilitation is summarized in Table 6.
A. CURRENT CLINICAL PRACTICE

Clinical guidelines77,154 recommend a multidisciplinary approach in managing cognitive impairment
including visual neglect but there is no clear and
specific guidance on the choice of interventions. As
a result, heterogeneous interventions are applied by
different institutions, depending on the local
guidelines, health professionals’ clinical experience,
and clinical resources.
B. TYPES OF REHABILITATION

Interventions include utilizing remaining intact
brain function (compensation), adaptation to the
impairment by using prosthetic devices or environmental modification (substitution), or retraining of
the impaired function (restitution).92 Although
certain interventions involve more than one mechanism, some fall outside this classification. We
summarize available interventions (Table 5) and
their effectiveness (Table 6). Traditionally, rehabilitation focused upon the compensatory and substitutive interventions as the brain was thought to
have limited regenerative ability. However, recent
evidence suggests that the brain has the ability
to reorganize and reconstruct following damage
(neuroplasticity),22,78,91,112 suggesting the possibility
of success of restitutive rehabilitation.
1. Compensatory
Visuospatial perception relies on intact internal
subconscious computation of the outer world
along with feedback from different sensory

125

VISUAL NEGLECT FOLLOWING STROKE
TABLE 4

How to Distinguish Visual Neglect from Homonymous Hemianopia
Criteria
Visual behavior
Awareness of deficit
Location of lesion
Uni- vs multi-modal deficit
Extinction
Drawing from memory
Visuospatial disorder
Line bisection
Attentional ‘‘cueing’’ strategies
Specific perimetric techniques
VEP and eye movement registration

Visual neglect
Lack of attention to contralesional
hemispace, independent of the
direction of gaze
Usually unaware of own deficit
Usually within the territory of the
middle cerebral artery
May associate with other modalities
like auditory, tactile and motor
Frequently associated49
Commonly leave out the details on
the affected hemispace
More commonly affected
Ipsilesional deviation
Presence of cueing may ameliorate
neglect (usually transiently)
Difficulty in maintaining central
fixation
Near normal response to stimulation
on both sides but prolonged
latency may be demonstrated on
the affected side160

Homonymous Hemianopia
Loss of visual field of contralesional
hemispace, with respect to the
position of the head and eyes
Usually retains awareness to a
certain extent
Usually within the territory of the
posterior cerebral artery
Strictly confined to visual modality
Less commonly associated
Normal and symmetrical
Usually not affected
Usually contralesional deviation122
Presence of cueing does not
modulate the disorder
Good control of central fixation
Marked disparity between the
normal and affected hemifield90

VEP 5 visual evoked potentials.
This table is modified from Kerkhoff et al.93

modalities.19,75,125,127,175 The compensatory, bottom--up approach of rehabilitation focuses on the
modulation of the afferent inputs towards the
central internalized process of the inner mind by
utilizing the remaining intact brain function and
various afferent/sensory modalities, including visual, tactile, vestibular, extraocular, and neck muscle
proprioception. This type of intervention does not
address the underlying lack of self-awareness of the
deficit by the affected individuals, resulting in only
short-lived improvement. Some interventions, such
as feedback training and r-TMS, may involve more
than one mechanism (Table 5).
2. Substitutive
This form of rehabilitation involves neither modulation of afferent inputs nor enhancement of selfawareness, but rather adaptation to the underlying
visual neglect with the aid of rehabilitative measures
such as prism adaptation, visual scanning therapy,
and environmental modification. These methods
potentially impact VN more than pure compensatory
interventions, as the improvement of VN relies on
both adaptation and subconscious active learning,
taking advantage of neuroplasticity.145 Also, the
affected individuals may sometimes benefit from
‘‘substitutive’’ measures rather than ‘‘restitutive’’
methods as they are so severely affected that the
underlying deficit cannot be appreciated (Table 5).

3. Restitutive
This form of rehabilitation focuses on retraining
of the impaired function92 and the modulation of
the internalized perception of the outer world,
rather than altering the afferent inputs. This may be
achieved by increasing self-awareness with mental
imagery, transcranial magnetic stimulation, virtual
reality--based space remapping, and, potentially,
feedback training (Table 5).
C. CURRENT EVIDENCE ON THE EFFECTIVENESS
OF REHABILITATION

As a result of our literature search, eight
systematic reviews3,20,50,82,103,106,136,140 concerning
the effectiveness of rehabilitation were identified;
they are summarized in Table 6.
Visual scanning therapy (VST) and prism adaptation are the two best-studied neglect rehabilitative
interventions, probably on account of the ease of
administration, cost-effectiveness, and easily reproducible positive results. Jutai et al,82 Luaute et al,106
and Pizzamiglio et al136 recommend the use of VST in
patients with VN. Generalization of task-specific effects
to a functional level has been documented by Geusgen
et al.50 However, the role of additional passive sensory
stimulation in the context of VST is inconclusive.136,153
There is strong evidence demonstrating that prism
adaptation helps rehabilitate VN.3,106 Long-term
beneficial effects can be achieved via a short period

126

Surv Ophthalmol 56 (2) March--April 2011

TING ET AL
TABLE 5

Summary of Underlying Rationale/Concepts for Various Types of Rehabilitation for Unilateral Neglect
Types
Compensation

Interventions
Visual scanning therapy

174,178

Optokinetic stimulation124
Limb activation143
Training with ‘‘cueing’’174
Neck muscle vibration86,88,152
Trunk rotation44,88
Caloric stimulation147
Eye patches44,179
Fresnel prisms148
Sustained attention training144
Substitution

Prism adaptation3,118,146

Diminished background
pattern and foreground clutter35
Restitution

Pharmacological treatment107
Mental imagery158
VR space remapping1

Compensation and
Restitution

Feedback training159

r-TMS/direct
polarization99,128,129

Unknown

Music therapy53

Brief Descriptions/Proposed Rationale
Re-develop an organized scanning pattern by learning
systematic right-to-left search
Induce left pursuit movement with the aid of leftward
moving background targets
Improve attention on the neglected hemifield by moving
the contralesional limb in the neglected hemispace
Activate attention on the neglected side with ‘‘cueing’’
stimuli (visual, auditory or tactile)
Re-center the spatial egocentric frame of reference by
modifying the afferent neck proprioceptive inputs
relative to the position of the head to the trunk
Re-center the spatial egocentric frame of reference by
modifying the afferent information relative to the
position of the head to the trunk
Induce nystagmus towards the affected side with cold
contralesional or warm ipsilesional caloric stimulation
Increase leftward saccades by occluding the unaffected
right hemifield
Shift the affected visual hemifield towards the unaffected
ipsilesional egocentric frame of reference
Improves spatial attention by generating general arousal
system
Recalibrate the midline of the egocentric reference frame
by using prism adaptation and successive visuo-motor
actions; an after-effect of leftward shift towards the
neglected hemifield following prism removal may
improve VN
Minimize the required visual attention during visual scene
navigation by reducing the background and foreground
environmental distracters
Improve general non-spatial attention by using dopamine
and norepinephrine agonists
Improve representational (imagery) neglect by using
visual or movement imagery
Remap the egocentric reference frame towards the
affected hemifield by using VR system
Increase patients’ self awareness (restitution) with
feedback sessions (video, mirror, verbal, visuomotor)
following certain tasks, point out their neglect behavior,
and teach them the ‘‘compensatory’’ strategies to
improve functional performance
Disrupt the integrated neural activity of the intact side,
dampen the attention to the ipsilesional side and
thereby restore the orientation balance between both
hemispheres (compensation),99,128 or alternatively,
induce the process of neuroplasticity (restitution)129
Stimulate cognitive function via sensory and emotional
stimulation

VR 5 virtual reality; r-TMS 5 repetitive transcranial magnetic stimulation.

of prism adaptation42 and ongoing improvement has
been observed even 5 weeks after the active phase of
rehabilitation.45 Such long-term effects do not occur
with passive Fresnel prism exposure,118 demonstrating that improvement relies on more than just
modulating the afferent inputs, and requires the
feedback loop of rewarded motor activity.
Nonetheless, the vast majority of the prism adaptation studies are case reports or small case series. A

recent single-blind randomized controlled pilot trial
of 34 neglect patients conducted by Turton et al168 has
shown that prism adaptation does not provide any
beneficial effect on the functional performance of the
VN patients, as measured by CBS and BIT, despite the
improvement of pointing behavior. The inconsistent
effect of prism adaptation observed across different
studies may be influenced by the inconsistency of
prism adaptation methods used, the disparity of

Synthesis of Reviews of Evidence of Effect of Interventions for Visual Neglect3,20,50,82,103,106,136,140
Reviews

Included Studies
3

Aims

31 studies—mixed trials of
different quality

Assess mainly the effectiveness
of passive sensory
stimulation, prism
adaptation, visual scanning
therapy, and
pharmacological treatment

Riggs 2007140

27 studies—11 RCTs, 3 nonRCTs, 13 case studies

Assess the effectiveness of
visuoperceptual therapy,
prism adaptation, eye
patches, and visuomotor
feedback

Geusgen 200750

7 studies—1 RCT, 3 single
subject, 2 pre-test post-test,
1 case control

Evaluate the ‘‘transfer’’ of the
effect of visual scanning
strategies from trained tasks
to daily tasks or daily living

Bowen 200720

12 studies—all RCTs

Assess overall effectiveness of
cognitive rehabilitation for
visual neglect on
independence of activities
of daily living

Lincoln 2006103

25 studies—12 RCTs of above
and 13 CCTs

Assess overall effectiveness of
various interventions
relating to visual neglect

Arene 2007

Key Findings
➢ Passive sensory stimulation only confers shortlived improvement
➢ Prism adaptation demonstrated long term functional gain
➢ Visual scanning therapy
has no significant impact
on overall function
➢ Improvement was observed with hemifield eye
patching, prism adaptation, and visuomotor
feedback, mainly by
means of standardized
neglect test like line bisection tests and cancellation tests
➢ Almost all confer positive
impact on daily tasks or
daily living but three of
seven were not statistically
tested
➢ Only spatiomotor cueing83 confers statistically
significant improvement
on performance in
standardized neglect
assessment
➢ None showed statistical
significance in functional
performance
➢ Rehabilitation observed
slight immediate and
persisting improvement
on standardised neglect
test
➢ Effect on functioning was
statistically insignificant,
for either immediate or
persisting effects

Limitation of Evidence
➢ Some of the interventions
were not included
➢ Majority of the included
studies are not of high
quality

➢ Effectiveness of other neglect rehabilitative interventions remains
uncertain
➢ Majority of the improvement not measured at the
functional level
➢ Lack of long-term followup
➢ Lack of long-term followup
➢ Only visual scanning
strategy was evaluated

VISUAL NEGLECT FOLLOWING STROKE

TABLE 6

➢ Many neglect rehabilitative interventions were
not included as they are
not RCTs

➢ Many neglect rehabilitative measures were not
included as they are neither RCTs nor CCTs

127

(continued on next page)

Reviews

Aims

54 studies -- RCTs, controlled
trials, crossover, casecontrol, single-case, and
case reports

Assess the effectiveness of
various interventions
relating to visual neglect

Pizzamiglio
2006136

12 studies— group studies and
single cases

Assess the effectiveness of
visual scanning therapy with
and without additional
passive sensory stimulation

Jutai 200382

32 studies, including RCTs,
crossover, cohorts, and
single group designs

Investigate effectiveness of a
variety of interventions
relating to visual neglect

Key Findings
➢ Improvement has been
observed following VST,
mental imagery and video
feedback training
➢ TR and NMV is partially
effective when coupled
with visual scanning
therapy
➢ Fresnel prism and passive
sensory stimulation do
not afford positive functional impact
➢ VST serves as a useful
neglect rehabilitative
intervention
➢ No beneficial effect
gained with additional
peripheral sensory
stimulation
➢ There is strong evidence
that rehabilitation specifically targeting visual neglect and visual scanning
improves functional
performance
➢ There is moderate evidence that Fresnel prisms
and hemifield patching
improve performance in
standardized neglect tests
➢ There is limited evidence
in favor of TENS, limb
activation, dopamine agonist therapy, caloric
stimulation improving visual neglect

Limitation of Evidence
➢ There is need for further
high quality evidence to
confirm the effect

➢ Only assesses limited rehabilitative interventions

Surv Ophthalmol 56 (2) March--April 2011

Luaute 2006

Included Studies
106

128

Table 6 (continued )

➢ Lack of quality appraisal
and meta-analysis
➢ Majority of included
studies are not of high
quality

CCT 5 controlled clinical trial; NMV 5 neck muscle vibration; RCT 5 randomized controlled trial; TR 5 trunk rotation; VST 5 visual scanning therapy; TENS 5
transcutaneous electrical nerve stimulation.
TING ET AL

129

VISUAL NEGLECT FOLLOWING STROKE

number and duration of therapeutic sessions instituted, and the difference in outcome measures
applied. This study did not address the anatomical
regions involved in their neglect patients. This is
important because some studies have suggested that
any potential beneficial effects of prism adaptation
may be lesion site--specific.151,155
The effectiveness of rehabilitation based on
passive sensory stimulation, such as eye patches,
Fresnel prism, trunk rotation, neck muscle vibration, limb activation, vestibular stimulation, and
optokinetic stimulation, remain inconclusive or
unsatisfactory.3,106
Although it seems logical that longer-term benefits
may be achieved with restitutive rehabilitation, the
evidence is limited. Within the context of restitutive
rehabilitation, Luaute et al106 consider mental imagery
and feedback training, as Grade B interventions,135
largely because the evidence of benefit is only based on
a case study of two patients.158 The efficacy of
pharmacological treatment (dopamine and noradrenergic agonists), transcranial magnetic stimulation128 or direct current polarization,99 virtual
reality--based space remapping,1 and music therapy
must be deemed inconclusive.158 There are conflicting
results from single case reports of the use of dopamine
and norepinephrine agonists to improve general
attention.3,10,72 Virtual reality--based space remapping
has shown to be of potential value, but has been
restricted to patients who have normal inferior
parietal/superior temporal lobes.1
The systematic reviews of Bowen et al20 and
Lincoln et al103 have concluded that none of the
interventions lead to a positive impact on functional
performance. They excluded the majority of the
research trials because of unsatisfactory levels of
evidence, highlighting the pressing need for high
quality research.
D. SUMMARY AND RECOMMENDATION FOR
REHABILITATION OF VISUAL NEGLECT

The overall efficacy of rehabilitation remains
uncertain. Based on the best available evidence, we
feel that visual scanning therapy and prism adaptation warrant consideration. In our experience,
education and training of family and close friends
to understand the nature of VN and how to assist VN
patients on a daily basis are equally important.

Unresolved visual neglect predicts poorer functional
and rehabilitation outcome in post-stroke patients.79,89,163,165 Longer-term follow-up is required,
as there has been no systematic reported evaluation
of outcome beyond 1 year.79

IX. Conclusion
VN is a common, but frequently overlooked,
condition. Greater awareness and understanding of
this condition should improve the quality of life of
post-stroke patients. Detection is by combination of
pen-and-paper tests, behavioral assessment tools,
clinical observation and history taking and, potentially, virtual reality assessment. Although there is
lack of robust evidence of the efficacy of VN
rehabilitation, visual scanning therapy and prism
adaptation warrant consideration. There is a pressing need for well designed, high quality research,
particularly randomized controlled trials, to
demonstrate the clinical efficacy of current rehabilitation strategies. Increasingly sophisticated neuroimaging tools, including magnetic resonance
scanning coupled with detailed clinical observation
and neuro-ophthalmic examination, will improve
understanding of the nature of VN, enabling
a deeper appreciation of how an individual with
VN recognizes, organizes, and orients ‘‘self’’ in
relation to the external environment.

X. Method of Literature Search
Multiple electronic databases (EMBASE, Cochrane
library, and Medline) were searched, reference lists
were hand-searched, and experts in the field were
contacted to identify peer-reviewed literature concerning visual neglect. Key literature which addresses
the functional impact, neuroanatomical causes,
assessment, and treatment of visual neglect was
identified. Certain keywords were used during the
literature search, including visual neglect, unilateral
neglect, visual inattention, and hemispatial neglect.

XI. Disclosure
The authors reported no proprietary or commercial interest in any product mentioned or concept
discussed in this article. Alex Pollock is employed by
the Nursing Midwifery and Allied Health Professionals (NMAHP) Research Unit, which is funded by
the Scottish Government’s Chief Scientist’s Office.

VIII. Prognosis
A few studies have observed spontaneous recovery
in patients with mild to moderate visual neglect,
especially during the acute phase,41 and recovery
has been seen up to 90 days post-stroke.126

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applications for the remapping of space in neglect patients.
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Surv Ophthalmol 56 (2) March--April 2011

2. Appelros P, Nydevik I, Karlsson GM, et al. Assessing
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Reprint address: Dr Darren SJ Ting, MBChB, Victoria Infirmary, Langside Road, Glasgow G42 9TY, U.K.

134

Surv Ophthalmol 56 (2) March--April 2011

TING ET AL

Outline
I. Introduction
II. Epidemiology
III. Varieties of neglect

3. Clinical observation and history-taking
from the patient and the near contacts
4. Recent development of assessment
technique

A. Modality (input/output)
B. Spatial representation
C. Range of space

C. Distinction between visual neglect and
other visual problems
D. Summary and recommendations for the
assessment of visual neglect

IV. Functional impact
V. Pathophysiology
A. Physiology of visuospatial perception
B. Spatially lateralized dysfunction of
neglect
C. Non-spatially lateralized dysfunction
sual neglect
D. Role of non-visual afferent inputs
E. Clinico-anatomical correlations of
neglect
F. Clinical syndromes associated with
neglect

VII. Rehabilitation of visual neglect
visual

A. Current clinical practice
B. Types of rehabilitation

of vi-

1. Compensatory
2. Substitutive
3. Restitutive

visual

C. Current evidence on the effectiveness of
rehabilitation
D. Summary and recommendation for rehabilitation of visual neglect

visual

VI. Assessment of visual neglect
A. Current clinical guidelines
B. How is visual neglect assessed?
1. Pencil-and-paper tests
2. Behavioral assessment tools

VIII.
IX.
X.
XI.

Prognosis
Conclusion
Method of Literature Search
Disclosure