cortex 44 (2008) 350–352

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Letter to Cortex

Incomplete ipsilesional hallucinations in a patient
with neglect
Gudrun M.S. Nysa,*, Tanja C.W. Nijboerb,c and Edward H.F. de Haanb,c
a

Laboratory for Neuropsychology, Department of Neurology, Ghent University, Belgium
Department of Experimental Psychology, Helmholtz Institute, Utrecht University, The Netherlands
c
University Medical Center Utrecht, Department of Neurology, The Netherlands
b

Visual hallucinations (VH) have been reported in a variety of
neurological conditions, such as occipital epilepsy, migraine,
and Lewy Body Dementia (Manford and Andermann, 1998).
A substantial number of patients with a posterior stroke initially experience VH (e.g., De Haan et al., 2007), often receding
in the ensuing weeks. These hallucinations usually occur in
the contralesional hemianopic field. There are only a few reports on the coexistence of hemi-neglect and VH (Chamorro
et al., 1990; Mesulam, 1981). In this study, we describe a patient
with left-sided neglect who experienced incomplete (rightside-only) hallucinations in the right intact hemifield. She
does not have a history of alcohol abuse, delirium, psychiatric
problems or psycho-stimulant medication use. We investigated her visuosensory status, visual perception and neglect.

1.

Case report

LZ is a 66-year-old right-handed female, who suffered a subarachnoid haemorrhage in September 2000. One day post-surgery (clipping), LZ developed vasospasms resulting in a large
right-hemispheric infarction involving occipital, parietal,
temporal and frontal regions. Retrospection of early neuropsychological reports suggested perceptual impairment and
severe left-sided neglect. In 2005, LZ’s husband noticed that
she experienced language problems and she was brought
into the hospital where a subdural haematoma was detected
in the left hemisphere. The language disorder disappeared following the placement of a subdural drain.

1.1.

Report of hallucinations

When LZ was admitted to our lab (July 2006), she reported regularly perceiving objects or animals which were not actually
there. She experienced these VH since her first stroke. She
had never informed her husband because she feared being delusional. The hallucinations were realistic and appeared consistently in the right hemifield or occasionally in central areas.
LZ realised that these images were hallucinations because ‘‘in
contrast to the rest of the world, these images are incomplete
on the left’’. The images always fit in the environment and always had the correct colour or form; they moved, but when
she moved her eyes or head in any direction or closed her
eyes the images disappeared. The images were only present
during the day and appeared only briefly (seconds). As an example, she told us that she frequently saw incomplete ducks
(only right-side visible) in the canal in front of her house. During the week following this interview, LZ told her husband
that she saw half of a duck again. Apparently, there was
a duck but her husband reported that it was swimming somewhere else on her left side. Other examples consisted of children on hemi-bicycles in her street or hemi-rabbits in the
park, and it remained unclear whether these objects were actually present on the left as the content of the ‘hallucination’
usually fit the scene. According to LZ, unrealistic images were
rare and were basically limited to the early phase post-stroke.
For example, a frequent hallucination at that time was that
she constantly saw her (deceased) mother on the painting in
the hospital.

* Corresponding author. Laboratory for Neuropsychology, Ghent University Hospital, De Pintelaan 185 (4K3), B-9000 Ghent, Belgium.
E-mail address: gudrun.nys@ugent.be (G.M.S. Nys).
0010-9452/$ – see front matter ª 2007 Elsevier Masson Srl. All rights reserved.
doi:10.1016/j.cortex.2007.10.009

cortex 44 (2008) 350–352

1.2.

Neuropsychological examination

LZ showed left-sided neglect on the Behaviourial Inattention
Test (Wilson et al., 1987): Line-Bisection 3/9, Star-Cancellation
47/54, Letter-Cancellation 35/40, Line-Cancellation 30/36, Figure-and-Shape-Copying 1/4, and Representational-Drawing
2/3. Dynamic perimetry showed consistent misses in the left
visual field which – in addition to her neglect – could be indicative of a comorbid hemianopia. As a test for representational
neglect (Rousseaux et al., 2001), LZ was asked to imagine the
map of the Netherlands and name as many towns as possible
from Workum (town in the north where she lives) looking
south and from Breda (town in the south) looking north
(2 min per viewpoint). She solely named locations towards
the right from the imagined viewpoint (Fig. 1).
Object recognition was intact (Boston Naming Test short
form: 81/90), but LZ was impaired on degraded object perception (Visual Object and Space Perception battery – VOSP:
Warrington and James, 1991). Space perception was severely
impaired; she typically perceived items in the left field as
appearing on the right side (VOSP), and showed spatial transposition of contralesional items towards the right side while
copying (Rey Complex Figure) and in visual memory (modified

351

Location Learning Task) (Kessels et al., 2006) (Fig. 1). This
transposition from left to right on both perceptual and visuomotor tasks has frequently been termed ‘allochiria’ (Lepore
et al., 2004).

2.

Discussion

This is the first report of incomplete hemi-hallucinations in
a patient with neglect. So far, incompleteness of hallucinations has only once been reported in a patient who suffered
from an occipital stroke resulting in a quadrantanopia
(Vogeley and Curio, 1998). The VH consisted of the lower
half of human figures which were limited to the borders of
the patients’ quadrantanopic field defect. The authors attributed the incompleteness of the hallucinations to ‘an aperture effect’, as if the deafferented quadrant of the primary
visual cortex was allowing in a part of the endogenously created image only at that location in the visual field (i.e., left
lower quadrant). In our patient, such an aperture effect cannot account for the incomplete hallucinations as LZ demonstrated no field effects on the right side of space where she
hallucinated.

Fig. 1 – Top: left: LZ’s enumeration of Dutch towns/villages from the Breda viewpoint when looking at the north of the
Netherlands and right: LZ’s enumeration of Dutch towns/villages from the Workum viewpoint when looking at the south of
the Netherlands. From both viewpoints, only right-sided locations are reported. Bottom: original stimulus material (mLLT)
(left) and objects placed on trial 3 (right).

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cortex 44 (2008) 350–352

Intriguingly, LZ was fully aware of the missing parts in her
‘hallucinations’, whereas she was rarely aware that she
missed items on the left in real life or when forming an endogenous image to command (e.g., the map of the Netherlands).
Although it is well-known that neglect patients may show
a dissociated spatial performance in processing imagined versus realistic images (Bisiach and Luzzatti, 1978), this is the first
report of a dissociation in neglect-related awareness between
imagining objects to command and spontaneous endogenously generated images.
Several mechanisms may account for LZ’s hallucinations.
First, given LZ’s allochiria, a potential neuropsychological
mechanism is that she displaced real objects on the left towards the right, which due to additional hemianopia and/or
object-based neglect resulted in an incomplete image. In other
words, this could mean that LZ was misinterpreting real
objects in her left hemifield as hallucinations, i.e., a kind of
reverse hallucination, in that perception of real objects –
because of an incomplete rendering and a shift in location –
are perceived as ‘‘not real’’. An alternative explanation might
be that the patient suffers from endogenously created hallucinations, perhaps partly triggered by the environmental context, which are incomplete because of her representational
neglect.
In conclusion, our patient experienced neglect and complex hemi-hallucinations in the attended hemifield for years.
This is the first report of hemi-hallucinations in a patient
with neglect with an intriguing selectiveness in location and
awareness, i.e., she was aware of the incompleteness of the
hallucinations but she was rarely aware that she neglected
items in real life.

Acknowledgements
This study was performed when the first author was still
working at Utrecht University. GN is now working as a postdoctoral researcher for FWO (Belgium). We thank the patient
and her husband for their never ending cooperation and
good humor. We would like to thank Dr. Ralph Hoffman and
an anonymous reviewer for their suggestions on an earlier
draft of this manuscript.

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Received 4 April 2007
Reviewed 30 July 2007
Revised 18 September 2007
Accepted 29 October 2007
Action editor Yves Rossetti
Published online 27 December 2007