Double dissociation between
representational personal and
extrapersonal neglect
S. Ortigue, PhD; P. Mégevand, MD; F. Perren, MD; T. Landis, MD; and O. Blanke, MD

Abstract—Background: Although perceptual and representational neglect are frequently associated, the demonstration of
a double dissociation between both neglect forms suggests that both rely on different central mechanisms. In addition,
perceptual neglect can be selectively observed within personal space or extrapersonal space. However, it is not known
whether the latter dissociation also exists in representational neglect. Methods: The authors investigated this question in
two brain-damaged patients with anatomically different lesions sites, using neuropsychological tests specifically designed
to assess perceptual and representational neglect in both personal and extrapersonal space. Results: Patients presented a
double dissociation with respect to personal and extrapersonal space in representational neglect. Conclusions: These data
suggest that the cerebral networks that process mental space representation use similar principles of space compartmentalization as those used by cerebral networks processing perceived space.
NEUROLOGY 2006;66:1414–1417

Patients with unilateral neglect fail to attend to or to
explore the space contralateral to their brain damage
in the absence of any primary sensory deficits. Unilateral neglect exists in response to sensory stimuli
(perceptual neglect), but also in the absence of such
sensory input, by imagining familiar spatial scenes
(representational neglect).1,2 Although these two
forms of unilateral neglect are frequently associated,1 they may occur independently. A few cases of
“pure” representational neglect have been described2,3 corresponding to the inability to describe
from memory the contralesional part of a familiar
environment, independently of the imposed imagined viewpoint.
Within the perceptual domain, space may be subdivided into different spatial compartments, such as
personal space (one’s own body) and extrapersonal
space, which comprises the near space (within reaching distance) and far space (beyond reaching distance).4 Whereas it has been demonstrated for
perceptual neglect that personal and extrapersonal
space can be selectively affected,5-7 patients with representational neglect have only been investigated
with respect to spatial imagery in extrapersonal
space using familiar city squares, familiar room interiors, or country maps.2 Yet, it is not known whether
a dissociation with respect to personal and extrapersonal space also exists in representational neglect.
This is relevant for the question of whether percep-

tual and mental spatial cognition rely on common or
separate organizational principles.2,3 We thus systematically assessed neglect patients with a battery
of tests specifically designed to test representational
neglect and perceptual neglect for personal and extrapersonal space. Here, we describe two patients:
one with representational neglect for personal, but
not extrapersonal space, and another patient with
the opposite pattern.
Case reports. Patient 1. A 67-year-old, right-handed baker
initially had a left-sided weakness and left hemihypoesthesia,
which partially recovered within 1 week. There was no visual field
deficit and no visual extinction. A detailed neuropsychological assessment including standard comprehension, naming, reading,
writing, phonologic, and semantic verbal fluency tasks did not
show any sign of aphasia. There was no deficit in verbal long-term
memory (Rey Auditory–Verbal Test). A mild dysexecutive deficit
was observed (Stroop, Luria Three-Step Task). Apart from the
spatial domain, mental imagery was flawless (drawing and verbal
descriptions from memory of objects and animals). MRI showed a
small lesion restricted to anterior part of the posterior limb of the
internal capsule in the territory of the anterior choroidal artery
(figure 1).
Patient 2. A 66-year-old, right-handed police officer had several short-lasting episodes of left hemisensory loss and left hemiataxia. At admission he had a left hemianopia, a left spatial
hemineglect, a left-sided weakness, and left hemihypoesthesia.
There was no tactile or auditory extinction. Detailed neuropsychological assessment including standard comprehension, naming,
reading, writing, phonologic, and semantic verbal fluency tasks
did not show any sign of aphasia. There was no deficit in verbal
long-term memory (Rey Auditory–Verbal Test) and no dysexecutive disorder. However, there was a left perceptual and represen-

From Functional Brain Mapping Laboratory (S.O.), University Hospital of Geneva, and Department of Fundamental Neurosciences, University Central
Medical School, Geneva, Department of Neurology (S.O., P.M., F.P., T.L., O.B.), University Hospital of Geneva, and Laboratory of Cognitive Neuroscience
(O.B.), Brain Mind Institute, Ecole Polytechnique Fédérale de Lausanne, Switzerland.
Supported by the Swiss National Science Foundation (3100-065096.01/2 and 3100-0650232.02; 3100-067874.02) and the Swiss Foundation for Biology and
Medicine (1223/PASMA 111563/1).
Disclosure: The authors report no conflicts of interest.
Received September 7, 2005. Accepted in final form January 23, 2006.
Address correspondence and reprint requests to Dr. S. Ortigue, Dartmouth Functional Brain Imaging Center, Center for Cognitive Neuroscience, Department of Psychology and Brain Sciences, Dartmouth College, 6162 Moore Hall, Rm. 432, Hanover, NH 03755; e-mail: stephanie.ortigue@dartmouth.edu
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Figure 1. The MR images of these patients were mapped
onto modified templates. Patient 1. MRI and template of
the brain showing a small ischemic lesion of the posterior
limb of the internal capsule in the territory of the right
anterior choroidal artery.16

tational spatial hemineglect, spatial dysgraphia (a tendency to
write predominantly on the right side of a sheet of paper, to
produce wandering lines with overlapping words and letters, and
to split words incorrectly),15 and spatial dyslexia (misreading text
appearing on the contralesional side of space, skipping from line
to line in reading written text, although reading individual words
was preserved).
Within 1 week, the left hemianopia regressed into an upper
left quadranopia and the left perceptual hemineglect, the spatial
dysgraphia, and dyslexia disappeared. Only the left representational visuospatial hemineglect persisted. MRI showed a rightsided lesion in the territory of the posterior cerebral artery,
involving the inferolateral thalamus, the splenium of the corpus
callosum, and parts of the medial temporal and occipital lobes
(figure 2).
Methods. Perceptual and representational neglect were tested
in both personal and extrapersonal space.
Perceptual neglect. Perceptual extrapersonal space. To examine neglect in extrapersonal space,8 different tasks were given
in near and far extrapersonal space.9 Assessment of these two
compartments is of particular interest, especially as a growing
body of evidence in functional neuroimaging has demonstrated
anatomic differences in healthy subjects between performing perceptual and motor tasks in near and far space.10,11 In the current
study, near extrapersonal space was assessed using the Line Bisection Task and the Bell Cancellation Task.8,9 The percentage
mean deviation was calculated for the Line Bisection Task. Misses
were scored for the Bell Cancellation Task (total of 35 items; 15
right, 15 left, 5 middle). Far extrapersonal space was assessed
using the Line Bisection Task9 (Patient 1) and a verbal description
(Patient 2) of a distant visual scene.
Perceptual personal space. Patients were asked to reach for
their left hand with the right hand, with eyes opened.5 A four-level
scale was used (0, normal performance; 1, the target is reached
with hesitation and is searched; 2, searching is stopped before the
target can be reached; 3, no attempt to reach the target).
We also carried out the Fluff Test7 and the Reformulated Comb
Test.7,12
The Fluff Test required the patients to reach with their right
hand for 15 targets (2-cm diameter) that were attached to their
body. Three targets were attached to the right side and three to
the left side of the torso (with respect to the frontal midline).
Three targets were attached to the right leg, three to the left leg,
and three to the left arm. No targets were placed on the right arm
because the task was performed with the right hand. Each patient
was blindfolded and asked to remove all targets.
In the Reformulated Comb Test, each patient was asked to
comb his hair for 30 seconds with the right hand. The number of
strokes applied to the right and left side of the head, as well as
ambiguous strokes, were measured to calculate the following
score7: xcomb ⫽ ([left – right strokes]/[left ⫹ ambiguous ⫹ right

Figure 2. Patient 2. MRI and templates of the brain showing ischemic embolic lesions in the territory of the right
posterior cerebral artery. (A) Lesion of the inferolateral
part of the thalamus impinging upon the posterior limb of
the internal capsule (thalamogeniculate branch of P2) and
a lesion of the splenium of the corpus callosum. (B, C) Medial temporal and occipital lesions.

strokes]) * 100. This value yields a score between –100% (total left
neglect) and ⫹100% (total right neglect).
Representational neglect. Representational extrapersonal
space. Each patient was asked to mentally visualize a familiar
square (the Place Neuve in Geneva; local version of the Piazza del
Duomo).1,2 This is a well-known place in Geneva with many wellknown buildings (figure 3). Each patient was asked to imagine
this square from two predefined opposing viewpoints (by 180°).1-3
These were at the entrance of the Parc des Bastions and at the
Théâtre de Genève. Each patient’s response, which was given
from one of these two viewpoints, served as a control for the other
viewpoint on the basis that a right-sided response from a viewpoint automatically becomes a left-sided response from its 180°
opposite viewpoint. In this sense, global numbers of reported
items might be different from one patient to another. Five normal
control subjects (mean age 72 ⫾ 4 years) performed this task. In
average, they reported 6.8 left-sided items and 7.1 right-sided
items. Their results showed no difference between the reported
left-sided items and the right-sided items (p ⫽ 0.49).
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Figure 3. The Place Neuve in Geneva with its principal
architectonic elements.
Representational personal space. We developed three tasks
for assessing the patients’ performance in representational personal space: the Modified Fluff Test, the Modified Comb Test, and
the Modified Razor Test.
The Modified Fluff Test required the patients to indicate, from
memory and with eyes closed, the location of 12 targets (2-cm
diameter) that were previously (5-minute delay) attached to their
body. Three targets were attached to the right side and three to
the left side of the torso (with respect to the frontal midline). One
target was attached to the right leg, one to the left leg, and four to
the left arm. No targets were placed on the right arm because, as
in the original Fluff Test, the task was performed with the right
hand. This modified version of the Fluff Test is considered to
assess the representational domain on the basis of the instruction,
which asks the patients to indicate from memory the previous
location of each target after they were removed by the examiner.
In the original version of the Fluff Test, the patients were asked to
reach each target while it was still on the patients’ bodies.
In the Modified Comb Test, each patient was asked to simulate
combing his hair for 30 seconds with the right hand, while he was
blindfolded. As in the original Comb Test, the number of strokes
applied to the right and left side of the head, as well as ambiguous
strokes, were measured to calculate the following score: xcomb ⫽
(left – right strokes)/(left ⫹ ambiguous ⫹ right strokes). This
value yields a score between –1 (total left neglect) and ⫹1 (total
right neglect).
In the Modified Razor Test,12 each patient was instructed to
simulate shaving himself for 30 seconds with the right hand,
while he was blindfolded. As in the initial Razor Test, the number
of strokes applied to the right and left side of the head, as well as
ambiguous strokes, were measured to calculate the following
score: xrazor ⫽ (left – right strokes)/(left ⫹ ambiguous ⫹ right
strokes). This value yields a score between –1 (total left neglect)
and ⫹1 (total right neglect).

Results. Perceptual neglect. Perceptual extrapersonal
space. Patient 1. In near space, the Line Bisection Task
(mean of deviation of ⫹5%) and the Bell Cancellation Task
(35/35 correct) were flawless. No far extrapersonal neglect
was observed (line bisection: ⫹4% of mean deviation).
Moreover, no reaction time difference was observed between the left (521 ⫾ 126 milliseconds) and right (561 ⫾
174 milliseconds) hemispace during a classic target detection paradigm (from the Test of Everyday Attention [TEA]
1416

battery) realized 12 days after hospitalization. Patient 2.
No near extrapersonal neglect was observed in the Line
Bisection Task (percent of mean deviation: ⫹7%) or the
Bell Cancellation Task (34/35 correct). The description of a
far distant visual scene was flawless (no far extrapersonal
neglect).
Perceptual personal space. Both patients performed
well in the Fluff Test (15/15 items detected) as well as in
the Reformulated Comb Test (x comb for Patient 1 ⫽
⫺12.5%; xcomb for Patient 2 ⫽ ⫺6%).
Representational neglect. Representational extrapersonal space. Patient 1. Familiar square description did
not exhibit any significant signs of hemineglect (4/5 on the
left side from the first viewpoint and 4/6 on the left side
from the 180° opposite viewpoint). All items on the right
side were correctly reported from both viewpoints. Patient
2. Familiar square description led to a strong left representational hemineglect. The patient reported only 4 of 10
items on the left side from the first viewpoint and 5 of 13
items on the left side from the 180° opposite viewpoint.
All items on the right side were correctly reported from
both viewpoints.
Representational personal space. Patient 1. The Modified Fluff Test revealed a mild left representational personal neglect, which was characterized by two systematic
left-sided omissions in the upper body. All items on the
right side were correctly reported. The Modified Comb Test
revealed a strong left representational personal neglect
characterized by a rightward deviation bias of ⫹69% and
⫹60%. The Modified Razor Test also revealed a strong left
representational personal neglect characterized by a rightward deviation bias of ⫹46% and ⫹29%. Patient 2. This
patient showed no representational personal neglect. The
Modified Fluff Test (12/12 items detected) and the Modified Comb Test (mean xcomb deviation ⫽ ⫺14%) were both
within normal range.

Discussion. We investigated whether the compartments of personal and extrapersonal space as
observed in perceptual space could also be demonstrated in imagined space. We systematically
searched for this dissociation and report here about
two patients without perceptual neglect, but with
selective representational neglect either for personal
space (Patient 1) or for extrapersonal space (Patient
2). From a purely behavioral viewpoint, this double
dissociation suggests that mental imagery relies on
the same or similar processing principles with respect to personal and extrapersonal space as perception does. It could be argued that the current
dissociation might be due to involved motor mechanisms as our tests for personal representational neglect depended on manual motor responses, whereas
our tests for extrapersonal representational neglect
depended on verbal motor responses. Yet, in both
patients, there were no signs of perceptual personal
neglect that was tested with the same manual motor
responses as the tests for representational personal
neglect that were pathologic in Patient 1. If representational neglect were indeed related to motor
mechanisms, one could postulate that this motor difference applied only for targets in representational

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space. Another difference between tests for personal
and extrapersonal representational neglect is that
tests for the former space relied on procedural (Comb
and Razor Tests) and short-term memory (Fluff
Test), whereas our tests for the latter space relied on
long-term memory. Although our results within representational personal space (in Patient 1) show that
neglect was found independently of the involved
memory mechanisms (procedural vs short term) and
that memory as examined by the neuropsychological
examination was normal in both patients, we cannot
exclude that memory-related differences between
personal and extrapersonal tests might have influenced our results.
The idea underlying the principle of double dissociation would, however, suggest that for our tasks,
different, though maybe overlapping, structures or
networks were used. Ideally, functional double dissociations should go along with clearly dissociated anatomic lesion sites. However, especially with cortical
lesions, many functionally dissociated neglect syndromes have shown large overlapping lesion. In the
current two cases, the lesions do not overlap, which
may allow some anatomicofunctional speculations.
The first case with a “pure” representational personal neglect is quite unique for two reasons: 1) To
our best knowledge, no case has yet been described
with “pure” personal representational neglect (as defined with the current tests), and 2) the lesion leading to this defect is very small, restricted to the
anterior part of the posterior limb of the internal
capsule in the territory of the anterior choroidal artery. Infarcts in the posterior limb of the internal
capsule are usually larger and may lead to severe
multimodal persistent neglect,13 particularly for visually guided movements,14 suggesting a disruption of connections between the pulvinar and the
parietal lobe. In our case, the visual thalamocortical transcapsular connections, producing extrapersonal neglect, have very probably been left intact.
We speculate that this might have led to a pure
personal neglect only in the representational domain, as with opened eyes, personal space was
unimpaired.
Our second case had several lesions in the territory of the right posterior cerebral artery. Most prob-

ably, the large inferolateral thalamic lesion was
responsible for the “pure” representational neglect of
extrapersonal space, as this kind of neglect has already once been reported with an isolated similarly
placed thalamic lesion.2 In this second case, visual
pulvinar–parietal connections were probably interrupted, whereas more anterior somatosensory
thalamoparietal connections were left intact. It is
noteworthy that in both cases, the lesions do not
touch upon the classic lesion site for perceptual neglect, which is the posterior lateral temporoparietal
junction. Our observation stresses the importance of
discrete subcortical lesions for the integrity of space
representation.
Acknowledgment
The authors thank the patients for their participation.

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