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Phantabulation
Citation for published version:
Cocchini, G, Lello, O, McIntosh, RD & Della Sala, S 2014, 'Phantabulation: A case of visual imagery
interference on visual perception', Neurocase: The Neural Basis of Cognition, vol. 20, no. 5, pp. 581-590.
https://doi.org/10.1080/13554794.2013.826689

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10.1080/13554794.2013.826689
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Neurocase: The Neural Basis of Cognition

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Cocchini et al (2014). Neurocase 20(5):581-590.

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Phantabulation:
A case of visual imagery interference on visual perception

Gianna Cocchini a,b, Owen Lello b, Robert D. McIntosh c and Sergio Della Sala c
a) Department of Psychology, Goldsmiths University of London, UK
b) Blackheath Brain Injury Rehabilitation Services, London, UK
c) Human Cognitive Neuroscience, Psychology, University of Edinburgh, UK

Running Title: Phantabulation

Key Words: Visual Imagery, Perception, Confabulation, Stroke

Address correspondence to:
Gianna Cocchini
Psychology Department
Goldsmiths University of London
New Cross
London SE14 6NW
U.K.
Email: g.cocchini@gold.ac.uk

Word count: 4,287

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Abstract
We report the case of a 52-year old man who, following rupture of an anterior
communicating artery aneurysm, presented with a phenomenon not previously described,
which we have labelled ‘Phantabulation’. Phantabulation is characterised by frequent and
purposeful interactions with contextually appropriate imagined objects. We suggest that this
phenomenon results from confusion between real and imagined objects, caused by failure to
inhibit florid visual-imagery, facilitated by cortical release mechanisms.

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Introduction
We report on the case of patient MT who, following the rupture of an anterior communicating artery
aneurysm, presented with a phenomenon not previously reported. He mimed actions with non-existent
objects, interacting with them appropriately to the context, and confabulating about them, in the
absence of any signs of classic hallucinations. For example, he would appear to smoke a cigarette and
extinguish it in an ashtray, though neither object was present. When asked to draw, he reached as if
for the real pencil on the table, but then mimed the picking up and drawing actions, leaving no visible
marks on the paper. He ignored the fact that his actions had no actual results, and could provide
detailed sensory descriptions of the (phantom) objects with which he was interacting. On direct,
repeated questioning, he was able to achieve insight into the imaginary nature of these objects; yet he
showed remarkably little concern about this behaviour. We have termed this phenomenon
“Phantabulation”, echoing a label given to the complex hallucinations of Charles Bonnet syndrome:
“Phantom visual images” (Schultz, Needham, Taylor, Shindell & Melzack, 1991).

Case Report
MT (not his real initials) is a right-handed (laterality quotient = 0.79; Oldfield, 1971) man with 11
years of formal education, who at the time of testing was 52 year old. He had a history of untreated
anxiety. Prior to his stroke, he had been a heavy drinker and smoked cannabis regularly. He was
admitted to hospital for the rupture of an aneurysm of the anterior communicating artery. An external
ventricular drain was inserted immediately and coil embolization of the right anterior communicating
artery was performed on the following day. A series of neuroimaging scans (see Figure 1) performed
ten days after the vascular accident showed a right ventro-medial frontal and intraventricular
haemorrhage. As it is typical in haemorrhages (Catani et al., 2012a), the lesion also damaged white
matter tracts, including short frontal lobe connections (Catani et al., 2012b) as well as the longer
arcuate fasciculus (Catani & Thiebaut de Schotten, 2008).
On clinical examinations, the patient proved blind in the right eye, in line with pre-chiasmatic
damage; he did not show motor or somatosensory deficits, his proprioception was also normal.

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--- Insert Figure 1 about here ---

MT came to our attention two months later, when he was transferred to the brain injury
rehabilitation ward. He appeared as an intelligent man with a good understanding of social context,
able to make occasional subtle and appropriate humorous jokes. General examination was part of
routine assessment but informed consent was obtained to further investigate some aspects of his
cognitive deficits.

Cognitive assessment
MT’s performance at formal assessment is reported in Table 1. He was disorientated to time and
space: he committed gross errors in estimating the current date, including the year and the month; he
frequently got lost in the ward and was unable to find his room or familiar communal rooms. There
was no evidence of verbal short-term memory impairment, simultanagnosia, neglect or constructional
apraxia. He performed poorly on most subtests of the VOSP, and just above cut-off on the Street
Completion task, which assesses visual perception of degraded figures. He responded correctly when
presented with classical illustrations to assess amodal perception (i.e. perception of a complete
structure when only some of its parts are presented). He performed very well on visual imagery tests,
with ceiling performance on two (object sizes and object colours) of the three sub-tests of the visual
imagery test battery. MT showed persistent long-term memory impairments and deficits on executive
tests. When asked about his problems, he mentioned only some vision and memory difficulties.

--- Insert Table 1 about here ---

Verbal Continuous Recognition Task
To avoid interference from visual perceptual problems, a verbal version of the classical Continuous
Recognition Task by Schnider and Ptack (1999) was devised. Names of objects illustrated in the

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Snodgrass and Vanderwart pictures (used in the original test) were read aloud, and MT was required
to say whether each word had already been presented in that current run. There were four runs and
each of them consisted of 80 words of which four targets were repeated eight times. Run 2 was given
immediately after the first run, with Run 3 after a five-minute break, and Run 4 after a further 30
minutes. At the beginning of each run, MT was explicitly instructed to detect targets repeated on the
current run only. MT showed a dramatic increase in false alarms between Run 1 and subsequent runs
(i.e. when previous targets where now functioning as distracters) (see Table 1). He tended to falsely
recognise previously encoded stimuli as current targets, suggesting a difficulty in suppressing
previously acquired information.

Source Monitoring Test
Some authors have observed that even healthy volunteers, especially older people, may have
difficulties in discriminating between external and internal sources of information (e.g., Johnson, De
Leonardis, Hashtroudi & Ferguson, 1995). These “reality monitoring errors” may occur if memory
traces derived from imagination are mistakenly identified as referring to an actual percept. To assess
whether Phantabulations may, at least in part, result from reality monitoring errors, MT and five agematched healthy controls (average age 60.0, sd= 3.5) were given a modified version of Henkel,
Johnson and De Leonardis’ (1998) test. They were asked to view a series of 30 large stimuli. Half of
the stimuli (Perceived condition) consisted of a concrete word with the related black and white line
drawing displayed underneath it (e.g. the word “APPLE” with a picture of an apple below it); the
other half (Imagined condition) consisted of a concrete word only (e.g. the word “BOX” written
without any picture). Stimuli for Perceived and Imagined conditions were piloted to balance them for
physical and semantic similarity.
Stimuli from each condition were displayed for six seconds each, in random order, and participants
were asked to estimate how many seconds it would have taken to draw the picture indicated by the
word. This drawing time estimation task was used to induce a mental image of the stimulus.
Participants were then engaged in a general conversation for 15 minutes, after which they were given
a surprise memory test in which the 30 words were re-presented, shuffled randomly with 15 new

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concrete words. For each word, participants were asked to state whether it had been presented earlier
with a picture, had been imagined, or was new.
MT identified most of the perceived stimuli correctly, but erroneously classed many imagined and
new stimuli as previously perceived (see Table 2). Misidentifications of imagined and new stimuli
were respectively seven and 17 standard deviations higher than those of the matched controls. This
strong tendency to misidentify even new stimuli as perceived suggests that MT elicited strong visual
images of the object not only in memory, but even during stimulus word viewing. This is supported
by a chance observation made during a practice trial: the examiner pointed out that, for a word that
MT had just read, there was no image and MT had to imagine one; to which MT commented with
surprise, “Oh...there isn’t one?!”.

--- Insert Table 2 about here ---

Observations of ‘Phantabulations’
Phantabulations occurred quite regularly and did not appear to be specific to any situation, time or
location. They could occur spontaneously during a conversation with the examiners, relatives or
friends, and sometimes during formal test sessions that were video or audio recorded, allowing later
evaluation and transcription. Phantabulations were mainly linked to visual information, and MT never
reported auditory hallucinations. However, some involvement of somatosensory modalities was
occasionally observed. On one occasion, for instance, MT held an imaginary bottle, commenting “it’s
quite light”. Phantabulations could be triggered by a variety of stimuli, which could be either
endogenous (e.g. talking about or imagining an object) or exogenous (e.g. seeing a basin could trigger
MT to begin brushing his teeth with an imaginary toothbrush).
Nevertheless, simply asking MT to imagine an object did not necessarily trigger a
Phantabulation. On a few occasions, MT was asked to look at a white sheet and to imagine that some
drawings (i.e., either a picture of a house or a clock) were illustrated on it. He was then encouraged to
enrich each image by responding to some questions about colour, size, pleasantness or the position of
details (e.g. “Point to the windows of the house” or “Point to the digits of the clock”). MT’s visual

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imagery was very good, he provided clear plausible responses and showed a good ability to form and
manipulate visual images. However, when asked whether there was a drawing on the sheet in front of
him, he said “…there is nothing here… it’s all my imagination”. Similarly, Phantabulations were not
easily induced by looking at another person’s behaviour. During a testing session, the examiner
pretended to grasp a box of sweets from a shelf, to pick one out and unwrap it; then MT was asked to
kindly put the wrapper in the bin. MT looked puzzled, he held out his hand to get the paper and then
asked “Are we pretending?”
By contrast, when MT generated a mental image either spontaneously or in response to current
needs, this often induced Phantabulations, as on numerous occasions when he was asked to draw
pictures or write his name. MT would usually pick up the real pencil, but mime the act of drawing in
the air just above the sheet, leaving no trace on the paper. When questioned about his drawings, he
would answer questions and point towards specific details of his “drawing”. MT seemed convinced by
his “perception” of reality and he was perplexed when contradictory evidence was presented. Indeed,
MT acted in accordance with his erroneous beliefs even in more intimate situations. On one occasion,
for example, a nurse guided him to the toilet door, as he had some difficulty in finding his way there.
Once alone in front of the toilet door, he started to undress himself to sit on an imaginary toilet. The
nurse quickly came back to guide him inside of the room, at which MT looked perplexed, as if he
could not understand why he was being asked to move.
These effects were quite robust and long-lasting. On several occasions, MT failed to acknowledge
explicitly that his drawing was only imagined, despite occasionally showing some insight. On one
occasion, while drawing a clock face, he spontaneously put down the pencil and commented “My
drawing is weird, you know?....a clock should be with numbers 1, 2,...”. Another time, after a long
conversation about a (phantom) drawing, the examiner asked him, “If I showed this drawing to T
[another examiner observing the examination] would he be able to tell what has been drawn on this
sheet?” MT replied: “It would be amazing if he could”, and only after several questions about the
reason for this, MT added “...because there is nothing there!” After this statement he immediately
stopped smiling and he looked at the sheet in a perplexed manner.

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Some further interesting aspects of MT’s behaviour are illustrated by the following episode.
During a testing session, MT complained of having a headache and asked permission to take a
painkiller. He then pretended to pull out with his right hand from the left pocket of his jacket a pill
dispenser, to take one of them and to drink some water from a glass, though none of these objects was
present in the room. The following (taped) conversation ensued:
Examiner: “How do you know… that these are the correct pills?”
MT: “I recognise them”
Examiner: “You recognise them from what?”
MT: “Well paracetamol is paracetamol…once you get to know them you can spot them from
anywhere…very distinctive the originals […]”
Examiner: “Are they square…are they …?”
MT: “Round”
Examiner: “Thick or thin?”
MT: “..pretty thin really, certainly not thick”
Examiner: “Are they red…?”
MT: “No they are white…yes, […]”
Examiner: “Would you like to show me one of these pills?”
MT: “Yes sure” [MT pulled out from his pocket an imaginary blister of pills and squeezed one out
onto the examiner’s hand adding “Just one paracetamol?” For the remaining part of the
conversation the examiner held her right hand open in clear view of MT.]
Examiner: “OK” […] Looking at the content of her hand the examiner added: “...and this is the
white pill that you have just taken? The same?”
MT: “Yes, exactly the same”
Examiner repeated: “Is it exactly the same?”
[MT nodded to confirm].
Examiner: “..and if I take this pill will my headache go away?”
MT: “It should do, yes”

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Examiner (looking at her hand) added: “You know...I have a problem… I can’t see the pill in my
hand”
MT (looked very serious and concerned): “You can’t really see it?”
Examiner: “No, I can’t”
MT: “You can’t see it…oh… this is because it is not there, is it?”
Examiner: “So it’s not there?”
MT: “No it’s not”
Examiner: “Am I holding something?”
MT: “No” […] “But I can give you a real one if you want” (giggling)
Examiner: “Yeah, is it here the real one?”
MT: “The real one is here” (again picking up an imaginary pill dispenser from the same pocket).
MT put on the table the imaginary pill dispenser and added “Here is the real one” and pretended to
put a pill on the examiner’s hand.
Examiner: “Can I have also a glass of water?”
MT nodded and put an imaginary glass of water on the table.
The examiner mimicked the action of picking up the glass with her left hand and she held it in
front of MT, then the examiner added “So, I’m holding a glass of water and a pill…”
MT: “Yes, the paracetamol”
Examiner: “The real one….this time?”
MT: “Yes, yes”
The examiner looked at her hands and added: “I have again a problem…. I can’t see them”.
MT (looking very perplexed) “You can’t see?”
Examiner: “No, I can’t see the glass...”
MT: “Oh gosh!”
Examiner: “What do you think?”
MT was visibly concerned and after some thinking added “It is not a question of lack of light, is
it?... The light is on, here… and it’s not dark”
Examiner: “Indeed”

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MT: “We can still use the torch (picking up with his right hand an imaginary torch, then pointing it
down on the top of the examiner’s hands and moving it left and right)... just to check if you can see
the light bouncing...”
Examiner: “Yeah...but why do you think that I cannot see these things?” [looking at her hands]
MT: “…it’s…it’s… because there’s nothing there, is it?”
Examiner:” Is nothing there?”
MT: “Yeah”
Examiner: “This explains why I cannot see them”
MT: “Yeah… it’s just pretending”
Examiner: “Ok, so were we just pretending?”
MT (looking a bit relieved): “Well... I think it looks in that way, isn’t it? really…logically”
Examiner: “Yes, it looks so. But before, you actually saw the pill in my hand?”
MT:” Well … it’s suggestion, isn’t it? I thought I did, I wanted to, so I did .…but I don’t think I
can actually see it to be honest…because it’s not there!” […]
Examiner: “Does this happen frequently?...To think that things are there when they are actually
not?”
MT: “Not often… fairly… rarely...when I’m very tired […]”

Finally, MT also showed a few instances of a phenomenon that looked like reduplicative
paramnesia for places. On one occasion, after a testing session, he welcomed the examiners into his
hospital room behaving as if this was his house. “This is my room where I live...it is my mum’s
house”. Once inside, he opened the door of an en-suite bathroom and added “Two beds, one here
(indicating the WC) and one there (indicating the basin)”. Then, walking towards the mirror as if to
avoid bumping into the two beds, he pointed to the mirror and added “This is the window”. Going
back to the bedroom MT claimed that it was his bedroom in the flat that his partner had decorated.

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Recovery and follow-up
About eight months after his brain lesion, MT showed a dramatic reduction in the number of episodes
of Phantabulation. Three months later, these had ceased completely, and he was discharged.
The examiners visited MT one last time, at home, 15 months after his acute brain lesion. He was
eager to converse with the examiners but was not much interested in completing formal tests; though,
on request, he drew a clock from memory flawlessly. He appeared much better oriented to space and
time, committing only one error on the date of the month (anticipated by one day). He still had a
visual deficit for the right eye, and mentioned some continuing visual and memory difficulties. Some
of his conversation clearly showed some degree of retrograde and anterograde amnesia. He had
difficulty remembering what had happened or what he had eaten the day before; and he could
remember only some of the people he had met at the hospital, and some related events, but quite
vaguely. He did not recognise the two examiners, despite having seen one of them on a daily basis
during his time on the ward, and the other on several occasions.
During the conversation, which lasted a couple of hours, he interacted normally with various
objects, smoking several cigarettes, drinking tea, and moving objects without any sign of
Phantabulation. His mother confirmed that he had never shown Phantabulations since he left the
hospital. When asked if he remembered having imagined objects that were not present, he looked
surprised and asked his mum if he really had done so.

Discussion
For about eight months, MT showed a highly unusual phenomenon, unique in our experience, in
which he appeared to interact purposefully with objects not physically present. These episodes of
‘Phantabulation’ were quite frequent and vivid, could occur at any time of day, and were triggered
either by MT’s urge to complete a task (e.g. performing a psychometric test) or by less explicit needs,
such as holding a cigarette during a conversation.

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MT could describe the imagined objects very accurately, providing rich sensory details to
questioning, mostly visual but sometimes also somatosensory. Phantabulations were emotionally
neutral, and always referred to contextually plausible objects. When challenged with clearly
contradictory information, MT tried to account for his Phantabulations with logical explanations,
often confabulating. Therefore, MT seemed able to reach logical conclusions, though they were based
on incorrect premises. On repeated questioning, he would usually capitulate eventually, concluding or
acknowledging that the objects must have been ‘pretended’. This suggests that the phenomenon was
not completely detached from monitoring of reality. Considering MT’s non-verbal communication, he
was apparently unaware of the unreal nature of his perceptions while he was experiencing them. He
typically looked puzzled when confronted with contradictory information, and quite relieved when he
managed to provide what he considered, a plausible explanation. Such “explanations”, together with
evidence of reduplicative paramnesia, are unusual in patients suffering from hallucinations and they
support the hypothesis of an important delusional component of Phantabulations.

MT had memory deficits and presented with confabulatory tendencies. However, his
confabulations were unusual as, contrary to classic confabulations (e.g., Kopelman, 2010),
they never concerned autobiographical or future thinking events, rather they involved solely
current events, and seemed to provide him with a means to rationalise his interactions with
imagined objects.
Phantabulation may appear to share some similarities with utilization behaviour
(Lhermitte, 1983). However, contrary to utilization behaviours (see e.g., Boccardi, Della
Sala, Motto & Spinnler, 2002), Phantabulations were not triggered by environmental cues but
rather by endogenous drives. Moreover, unlike utilization behaviour (e.g., Besnard et al.,
2010) the actions characterising Phantabulation episodes were never socially inappropriate.
Despite some points of resemblance, MT’s behaviour also cannot be classed within any of the
various types of hallucinations described in the literature. Before brain damage, MT was a heavy
drinker and cannabis user. Withdrawal from these substances may cause brief pareidolic
hallucinations whose content often consists of perceiving distorted animals or persons (Lilliputian

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hallucinations; Sims, 2003) and which are usually associated with tremor, occasional loss of
consciousness and altered arousal with sleep disorders, such as insomnia and nightmares (Manford &
Andermann, 1998). Phantabulations showed none of these features, and MT never reported sleep
problems. They also appeared quite distinct from hallucinations associated with psychiatric
syndromes, which are predominantly auditory, with recurrent themes of high emotional valence, often
delusional and triggered by anxiety (e.g., Sims, 2003; David, 2004; Pierre, 2010). Interaction with the
“object” of the psychiatric hallucinations is highly unusual and very limited (Manford & Andermann,
1998; Sims, 2003), where such interaction was a defining characteristic of Phantabulation. Moreover,
Phantabulations were always contextually appropriate, such as holding a pen to perform a drawing,
which is not typical of psychiatric hallucinations.
Visual hallucinations following brain damage are a central feature of the Charles Bonnet
syndrome. These hallucinations appear within the blind visual field (e.g., Vaphiades, Celesia &
Brigell, 1996) especially under conditions of dim light or when the patients are somnolent (e.g., Kazui
et al., 2009; Schulz et al., 1996). In common with sufferers of Charles Bonnet syndrome, MT showed
a visual impairment, due to damage to the visual pathway coupled with intact visual primary cortex
(ffytche, Howard, Brammer, Woodruff & Williams, 1998). Moreover, Phantabulations occurred more
frequently, though not solely, in MT’s blind visual field. However, the content of hallucinations in
Charles Bonnet syndrome tends to be recurrent (e.g., Manford & Andermann, 1998), occasionally
bizarre and amusing (ffytche et al., 1998) but not purposeful. Such patients are well aware of the
unreal nature of their hallucinations while they are experiencing them (ffytche et al., 1998; Lalla &
Primeau, 1993; Schultz et al., 1996; Teunisse, 1996; Kazui et al., 2009) and show very limited
interaction, if any, with them. For example, Kazui et al.’s (2009) patient, claimed not to be able to
touch the cats “despite her efforts to do so” (p. 79). The purposeful, contextually appropriate
interaction with the imagined objects therefore distinguishes Phantabulations clearly from the
hallucinations observed in Charles Bonnet syndrome.
Some authors have suggested that a cortical release phenomenon may be responsible for
hallucinations. Indeed, while perception of visual stimuli normally inhibits endogenous activation of
the visual cortex, in the absence of exogenous information, the spare visual areas would suffer from

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sensory deprivation, releasing these areas from the normal regulation system (Cogan, 1973) and
leading to the formation of hallucinations as in Charles Bonnet syndrome (Kazui et al., 2009; Manford
& Andeermann, 1998; ffytche et al., 1998). However the cortical release explanation predicts a
relatively “casual”, simple, and probably recurrent content of hallucinations, which are unlikely to
change while occurring. On the contrary, MT’s phenomenological perceptions were apparently
complex and tightly linked to current context and his actual needs, more in line with a top-down
process. That is, he “perceived” a toothbrush when he needed to brush his teeth, and he “perceived” a
painkiller pill when he had headache. He never reported contextually incongruous hallucinations.
Unlike patients showing hallucinations, MT seemed to “reinterpret” reality according to specific
needs. For example, as in reduplicative paramnesia, he seemed to “reduplicate” objects. However,
vividness of Phantabulations is crucial as MT actually interacted with the imaginary objects to a much
greater extent than what is observed in classical reduplicative paramnesia. It is therefore important to
explain why MT “saw” in first place non-existent objects and why he perceived exactly the objects
that were functional to his goal. A possible explanation may be found in a combination of factors also
involving visual-imagery.
The role of visual-imagery in false perception is not new and other authors have suggested that
“complex visual hallucinations […] could be initiated by visual imagery” (Wünderlich et al., 2000; p.
561; see also Goldenberg, Müllbacher & Nowak, 1995). MT’s performance on the source monitoring
tests confirms his tendency to confuse imagined with real information, and his performance on the
verbal continuous recognition task suggests a difficulty in suppressing previous information.

MT’s visual imagery was well preserved in formal tests and he was clearly imagining in fine detail
some of the phantom objects he interacted with, and the phantom drawings he produced. Interestingly,
ffytche et al. (1998) observed that the releasing mechanism could also involve ventral extrastriate
activity and other authors observed additional activation of frontal and parietal cortex, suggesting that
extrastriate activity may be modulated by frontal and parietal top-down mechanisms that mediate
“retrieval of object representations from long-term memory and their maintenance through visual
imagery” (Ishai, Ungerleider & Haxby, 2000; p. 979). MT’s executive processes are compromised, as

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confirmed by his poor performance on some relevant tests (e.g., Brixton test). Therefore, visual
imagery may account for the highly purposeful content of Phantabulations, which may have been
enhanced by the cortical release mechanism and lack of inhibition due to the frontal damage.
Phantabulations are characterised by the purposeful interaction with contextually appropriate
imagined objects. We suggest that these episodes, in patient MT, may depend on a combination of
phenomena, whereby the effects of a top-down mechanism involving florid visual-imagery is
facilitated by cortical release due to frontal damage, resulting in a confusion between real and
imagined objects. These abnormal percepts are probably enhanced by an associated malfunction of
the fronto-parietal pathway, which fails to inhibit the imaginary processes and the evocation of their
related actions.

Acknowledgements. We are grateful to Nicoletta Beschin for her help in mapping the patient’s lesion
reconstructed in Figure 1.

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REFERENCES
Boccardi, E., Della Sala, S., Motto, C., & Spinnler, H. (2002) Utilisation behaviour consequent to
bilateral SMA softening. Cortex, 38, 289-308.
Besnard, J., Allain, P., Aubin, G., Osiurak, F., Chauviré, V., Etcharry-Bouyx, F., et al. (2010).
Utilization behavior: Clinical and theoretical approaches. Journal of the International
Neuropsychological Society, 16, 453-462.
Catani, M., Dell'Acqua, F., Bizzi, A., Forkel, S.J., Williams, S.C., Simmons, A., Murphy, D.G., &
Thiebaut de Schotten, M. . (2012a) Beyond cortical localization in clinico-anatomical correlation
Cortex, 48 (10), 1262-1287.
Catani, M., Dell’Acqua, F., Vergani, F., Malik, F., Hodge, H., Roy, P. Valabregue, R. & Thiebaut de
Schotten, M.. (2012b) Short frontal lobe connections of the human brain. Cortex, 48 (2), 273291.
Catani, M. & Thiebaut de Schotten, M. (2008) A diffusion tensor imaging tractography atlas for
virtual in vivo dissections. Cortex, 44 (8), 1105-1132.
Cogan, D.G. (1973). Visual hallucinations as release phenomena. Albrecht von Graefes. Arch Klin
Exp Ophthalmol, 188, 139-150.
David, A.S. (2004). The cognitive neuropsychiatry of auditory verbal hallucinations: an overview.
Cognitive Neuropscyhiatry, 9, 107-123.
Elizabeth, K., Warrington, E.K., & James, M. (1991). Visual Object and Space Perception Battery
(VOSP). Harlow: Pearson Education Limited.
ffytche, D.H., Howard, M.J., Brammer, M.J., Woodruff, DP., & Williams, S. (1998). The anatomy of
conscious vision: an fMRI study of visual hallucinations. Nature Neuroscience, 1, 738-742.
Goldenberg, G., Müllbacher, W., & Nowak, A. (1995). Imagery without perception- A case of
anosognosia for cortical blindness. Neuropsychologia, 33, 1373-1382.
Hanley, J.R., Young, A.W., & Pearson, N.A. (1991). Impairment of the visuo-spatial sketch pad. The
Quarterly Journal of Experimental Psychology, 43, 101-125.
Henkel, L.A., Johnson, M.K., & De Leonardis, D.M. (1998). Aging and source monitoring: Cognitive
processes and neuropsychological correlates. Journal of Experimental Psychology: General, 127,
251-268.
Ishai, A., Ungerleider, L.G., & Haxby, J.V.(2000). Distributed neural systems for the generation of
visual images. Neuron, 28, 979-990.
Johnson, M.K., De Leonardis, D.M., Hashtroudi, S., & Ferguson, S.A. (1995). Aging and single
versus multiple cues in source monitoring. Psychology and Aging, 10,507-517.
Kaniza, G. (1980) Grammatica del vedere. Bologna: Il Mulino.

16

Cocchini et al (2014). Neurocase 20(5):581-590.

Page 17 of 22

Kazui, H., Ishii, R., Yoshida, T., Ikezawa K., Takaya, M., Tokunaga, H., Tanaka, T., & Takeda, M.
(2009). Neuroimaging studies in patients with Charles Bonnet Syndrome. Psychogeriatrics, 9, 7784.
Kopelman, M.D. (2010). Varieties of confabulation and delusion. Cognitive Neuropsychiatry, 15, 1437.
Lalla, D., & Primeau, F. (1993). Complex visual hallucinations in macular degeneration. Canadian
Journal of Psychiatry, 38, 584-586.
Lhermitte, F. (1983). 'Utilization behaviour' and its relation to lesions of the frontal lobes. Brain,106,
237-255.
Manford, M. & Andermann, F. (1998).Complex visual hallucinations. Clinical and neurobiological
insights. Brain, 121, 1819-1840.
Mioshi, E., Dawson, K., Mitchell, J., et al. (2006)The Addenbrooke's Cognitive Examination Revised
(ACE-R): a brief cognitive test battery for dementia screening. Int J Geriatr Psychiatry, 21,107885.
Oldfield, R.C. (1971). The assessment and analysis of handedness: The Edinburgh Inventory.
Neuropsychologia, 9, 97–113.
Pierre, J.M. (2010) Hallucinations in non psychotic disorders: Toward a differential diagnosis of
“hearing voices”. Harv Rev Psychiatry, 18, 22-35.
Randolph, C. (1998) Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).
Harlow: Pearson Education Limited.
Rorden, C. & Brett, M. (2000). Stereotaxic display of brain lesions. Behavioural Neurology, 12, 191200.
Schnider, A. & Ptak, R. (1999). Spontaneous confabulators fail to suppress currently irrelevant
memory traces. Nature Neuroscience, 2, 677-681.
Schultz, G. & Meltack, R. (1991). The Charles Bonnet syndrome: ‘Phantom visual images’ [Review].
Perception, 20, 809-825.
Schultz, G., Needham, W., Taylor, R., Shindell, S., & Melzack, R. (1996). Properties of complex
hallucinations associated with deficits in vision. Perception, 25, 715-726.
Sims, A. (2003). Pathology of perception. (pp. 90-116). In: A., Sims (Ed.) Symptoms in the mind: An
introduction to descriptive psychopathology. Philadelphia: Saunders Elsevier.
Spinnler, H. & Tognoni, G. (1987). Gruppo italiano per lo studio neuropsicologico
dell’invecchiamento. Standardizzazione e taratura italiana di test neuropsicologici. The Italian
Journal of Neurological Sciences, 6, 20–119.
Teunisse, R.J., Cruysberg, J.R., Hoefnagels, W.H., Verbeek, A.L., & Zitman, F.G. (1996). Visual
hallucinations in psychologically normal people: Charles Bonnet’s syndrome. Lancet, 347, 794797.

17

Cocchini et al (2014). Neurocase 20(5):581-590.

Page 18 of 22

Vaphiades, M.S., Celesia, G.G., & Brigell, M.G. (1996). Positive spontaneous visual phenomena
limited to the hemianopic field in lesions of central visual pathways. Neurology, 47, 408-417.
Wechsler, D. (1997). Wechsler Adult Intelligence Scale – Third Edition (WAIS–III) Pearson.
Wilson, B., Cockburn, J., & Halligan, P.W. (1987). Behavioural Inattention Test. Tichfield, Hants:
Thames Valley test Company.
Wünderlich, G., Suchan, B., Volkmann, J., Herzog, H., Hömberg, V., & Seitz, R.J. (2000). Visual
hallucinations in recovery from cortical blindness. Archives of Neurology, 57, 561-565.

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Table 1. MT's performance on a battery of cognitive tests.
TEST1

MT scores #

Cut-off
Test interpretation

Repeatable Battery for the Assessment of Neuropsychological Status
Immediate memory - index score (0-130)
57
Visual/constructional - index score (0-130)
50
Language - index score (0-130)
75
Attention - index score (0-130)
85
Delayed memory - index score (0-130)
40
TOTAL SCORE - index score (0-130)
52

Cut-off
80
80
80
80
80
80

Addenbrooke's Cognitive Examination
Attention and orientation (0-18)
Memory (0-26)
Fluency (0-14)
Language (0-26)
Visuo-spatial (0-26)
TOTAL SCORE (0-100)

15
12
9
26
12
74

Cut-off
17
18
9
24
15
86

Verbal short-term memory
Span Forward (0-16)
Span Backward - (0-14)

7
6

4
4

Street Completion Test
Corrected score (0-14)

3.25

2.25

Constructional Apraxia Test
Corrected score (0-14)

11.75

8

Visual-imagery Test
Colour (0-25)
Animal's Tails (0-20)
Size comparison (0-16)

25
15
16

22.7 ***
14.8 ***
16 ***

18
9
8
2
16
1
17
6
3

Test interpretation
Pass
Fail
Fail
Fail
Fail
Fail
Fail
Fail
Fail

Visual Object and Space Perception Battery
Screening test (0-20)
Incomplete Letters (0-20)
Silhouettes (0-30)
Object Decision (0-20)
Progressive Silhouettes (0-20)
Dot counting (0-10)
Position Discrimination (0-20)
Number Location (0-10)
Cube Analysis (0-10)

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Cocchini et al (2014). Neurocase 20(5):581-590.
Visual Illusions
Amodal completion
- 3D cube behind bars
- Four black circles partially covered by
rectangles

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"a cube with bars on it"

Expected response

"4 circles and 4 rectangles"

Expected response

**

No evidence of neglect

3

No evidence of neglect

Neglect Tests
Line cancellation (0 -40)
Drawings from memory (house, person,
flower) (0-3)
Simultanagnosia Test
Colour test (random, single and mixed
conditions) (0-6)
Line length test (complete and separate
shapes) (0-6)

6

No evidence of simultanagnosia

16

No evidence of simultanagnosia

Stroop Test##
Coloured letters (0-6)
Neutral (0-9)
Congruent (0-6)
Incongruent (0-6)

6
9
6
6

Ceiling performance
Ceiling performance

Hayling and Brixton Test
Hayling - Overall scaled score (1-10)
Brixton - Overall scaled score (1-10)

4
2

Low average
Abnormal

Continuous Recognition Task - verbal version
Run 1
Run 2 (immediately after)
Run 3 (5 minute delay)
Run 4 (30 minute delay)

Hits %
89
75
93
86

FAs %
6
78
60
67

===
Increment on FAs compared to
Run 1: deficit in suppressing
previously encoded information

# Abnormal test performance is indicated in bold.
** MT cancelled the lines without touching the sheet so no mark was left. From direct observation, MT
clearly attended to all stimuli.
*** Cut-off scores represent the value at 2 SDs from age-matched controls' average performance. Data
taken from Hanley et al., 1991.
## Patients' responses were very quick. At the end of the test MT added: "I concentrated on the task and
ignored the different colour".
1

Repeatable Battery for the Assessment of Neuropsychological Status (Randolph, 1998); Addenbrooke's Cognitive
Examination - revised (Mioshi et al., 2006); Verbal short-term memory (Wechsler, 1997); Street CompletionTest
(Spinnler & Tognoni,1987); Contrustional apraxia test (Spinnler & Tognoni,1987); Visual-imagery test (Hanley et al.,
1991); Visual Object and Space Perception Battery (Warrington & James, 1991); Visual illusions (taken from Kanizsa,
1980- figures 2.4 and 2.6); Neglect tests (from BIT; Wilson, et al., 1987); Simultanagnosia test (Humphreys &
Riddoch, 1993); Stroop test (Ridley, 1935); Hayling and Brixton test (Burgess & Shallice, 1997); Continuous
recognition task (Schnider & Ptack, 1999).

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Table 2. MT's and matched controls' performance on the Source Monitoring Test.
Perceived stimuli
recognised as
perceived

MT
Healthy
controls

86.7*
mean
sd

72.0
19.1

imagined new

Imagined stimuli
recognised as

New stimuli
recognised as

perceived imagined new

perceived imagined new

6.5

6.5

46.7**

26.7

26.7

53.3*** 13.3

33.3

12.0
11.9

16.0
10.1

5.3
5.6

90.7
3.7

4.0
3.7

1.3
3.0

96.0
6.0

2.7
3.7

Correct responses are underlined
* within 1 standard deviation from norms
** 7.4 standard deviations higher than norms
*** 17.4 standard deviations higher than norms

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Figure 1. Reconstruction of MT’s area of lesion (MRIcro, www.micro.com, Rorden and Brett, 2000)
at 10 days post-stroke. The patient’s lesion was superimposed onto a 2D axial rendering on the
Montreal Neurological Institute (MNI) representative brain in stereotactic space. Note that the right
side of the reproduction corresponds to the right side of the brain.

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