Charles Bonnet syndrome—elderly people and visual hallucinations
BMJ 2004; 328 doi: https://doi.org/10.1136/bmj.328.7455.1552 (Published 24 June 2004) Cite this as: BMJ 2004;328:1552All rapid responses
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Dear Editor
I was interested to read your recent article describing Charles
Bonnet syndrome. This syndrome is of visual hallucinations in a partially
sighted or blind person, who has no mental illness or dementia. There is
apparently no known treatment.
Six weeks ago I was called to see a male patient aged 81. His wife
was concerned that he was becoming demented. He is a man who is partially
sighted and described seeing poached eggs on his mantelpiece and persons
sitting in chairs next to him. He was fully aware that these
hallucinations were not real and they did not particularly disturb him.
He had had the hallucinations for several weeks.
When I saw him there was no doubt that he was not depressed and was
not having a dementing process. Physical examination was perfectly normal
other than generalised spondylosis, which caused him some degree of
dizziness. I explained to him and his wife that I thought he had Charles
Bonnet syndrome. I suggested that I ask a Consultant Psychiatrist to see
him to confirm the diagnosis. He and his wife were quite happy with that,
but he also was concerned about his dizziness. I explained that his
cervical spondylosis was responsible for this, but I prescribed
Betahistine 16mg tds.
Several days later the Consultant Psychiatrist saw him at his home.
She agreed that he had Charles Bonnet syndrome but was quite surprised
that his hallucinations had completely disappeared. I have seen him on
several occasions since then and there has been no recurrence of the
visual hallucinations. He continues to take Betahistine.
There are several references to Charles Bonnet syndrome on the
internet but none says there is any treatment. Could his hallucinations
have disappeared because of the reassurance that he was not going mad, or
could Betahistine indeed be helpful for the syndrome?
Yours sincerely
Dr P J Hobson
Newgate Medical Group, Worksop
Competing interests:
None declared
The patient whose case is described has given signed informed consent to publication.
Competing interests: No competing interests
We read with interest Jacob, Prasad, Boggild and Chandratre’s article
on a classical presentation of Charles Bonnet Syndrome(1). They correctly
highlight the continuing debate over whether Charles Bonnet syndrome
requires an association with eye disease or not. The reason for this is
that there are still two definitions of Charles Bonnet syndrome being used
concurrently in clinical practice.
The controversy started with De Morsier himself when, having defined
Charles Bonnet syndrome in 1936 as formed visual hallucinations in the
psychologically normal elderly patient in association with eye disease, he
redefined it in 1967 to formed visual hallucinations in elderly people
with retained insight and thus removed the necessity for eye disease at
all(2).
These 2 definitions continue to be used interchangeably. Thus the
paper by Podoll et al(3) cited in Jacob’s article contains a mixture of
patients with and without eye disease. None of the 4 patients referred to
with Charles Bonnet syndrome and ‘normal’ visual acuities (authors’
classification) have significant eye pathology. The definition of Charles
Bonnet used for these particular patients is therefore the more recent of
De Morsier’s.
As Jacob et al report, the primary theory for aetiology is
deafferentation. It is hypothesised that reduced sensory input to the
visual cortex leads to Charles Bonnet ‘release hallucinations’.
Deafferentation is therefore dependent on concurrent pathology of the
anterior visual pathway. However other factors such as social isolation
may also play a role(4) since not every elderly patient with reduced
vision develops Charles Bonnet syndrome.
Although the two definitions have their uses, it is important for
authors to be aware of both particularly when comparing studies. We
suggest that the classification of Charles Bonnet as formed visual
hallucinations in psychologically normal elderly patients continues to be
clinically useful but that the more specific definition of formed visual
hallucinations in elderly patients with retained insight in combination
with eye disease is more robust(2) and has now survived almost two and a
half centuries since Charles Bonnet’s original observations.
1. Jacob A, Prasad S, Boggild M, Chandratre S. Charles Bonnet
syndrome-elderly people and visual hallucinations. BMJ 2004; 328: 1552-
1554. (June 26th).
2. ffytche DH, Howard RJ. The perceptual consequences of visual loss:
positive pathologies of vision. Brain 1999; 122: 1247-1260.
3. Podoll K, Osterheider M, Noth J. Das Charles Bonnet-syndrom.
Fortschr Neurol Psychiat 1989; 57: 43-60.
4. Menon GJ, Rahman I, Menon SJ, Dutton G. Complex Visual
Hallucinations in the Visually Impaired: The Charles Bonnet Syndrome. Surv
Ophthalmol 2003; 48: 58-72.
Competing interests:
None declared
Competing interests: No competing interests
Editor- Jacob et al (1) described a textbook case of the Charles-
Bonnet Syndrome (CBS). They describe this syndrome as uncommon, but quote
an incidence highlighted in my review of the syndrome in 2003 (2), of 10-
15%. Naturally, the referral of such patients often falls via general
practitioners to Ophthalmologists or Psychiatrists as most patients have
visual hallucinations associated with visual loss. This is supported by
the large volume of literature about this condition being published in
journals aimed at these specialties. I believe the incidence of CBS is
far greater than that documented, as patients in this predominately
elderly group are in fear of being labeled with insanity and thus only
admit to the hallucinations on direct questioning. A large number of
patients in ophthalmic practice are visually impaired and if asked, the
majority will admit to CBS type hallucinations, only to be relieved to
know that insanity has been ruled out. This in it self may alleviate the
hallucinations.
It must be pointed out, however, that there is no universal agreement
that visual impairment is in fact associated with the hallucinations.
Certainly, no clear level of visual acuity at which CBS occurs has been
documented. Patients with visual impairment of any cause and any level of
acuity may be susceptible to CBS.
Although the theory for CBS hallucinations was only touched on by the
authors, I agree that the mechanism is uncertain. However, the sensory
deprivation theory provides the most sensible explanation for such
hallucinations (3). This can be thought of as phantom visions, similar to
those of ‘phantom limb’ syndrome. In the absence of a normal afferent
input, the visual cortex exhibits spontaneous activity, giving rise to
conscious imagery. A similar syndrome is found with patients suffering
acquired deafness, resulting in musical auditory hallucinations (4).
Undoubtedly, greater awareness of CBS in the general medical field is
welcomed.
1. Jacob A, Prasad S, Boggild M, Chandratre S. Charles Bonnet
Syndrome-elderly people and visual hallucinations. BMJ 2004;328:1552-4
2. Menon GJ, Rahman I, Menon SJ, Dutton GN. Complex visual hallucinations
in the visually impaired: the Charles Bonnet Syndrome. Surv Ophthalmol
2003;48:58-72
3. Bartlett JEA: A case of organised visual hallucinations in an old man
with cataract, and their relationship to the phenomena of the phantom
limb. Brain 1951;74: 363-373
4. Griffiths TD: Musical hallucinosis in acquired deafness: Phenomenology
and brain substrate. Brain 2000;123: 2065-2076
Competing interests:
None declared
Competing interests: No competing interests
A relative with Macular Degeneration has severe bouts of Charles
Bonnet Syndrome visions. Sometimes these are triggered by stress but is it
possible that use of statins to reduce cholesterol could also be a factor?
Recent treatment with statins has co-incided with severe bouts of visions.
It seems amazing given the number of people with age-related macular
degeneration that the relative's GP and Hospital Opthalmic department
claim no knowledge of CB syndrome.
Competing interests:
None declared
Competing interests: No competing interests
Is it correct for an elderly gent with known obstructive airways
disease to be taking a beta blocker?
Competing interests:
None declared
Competing interests: No competing interests
I was surprised not to see any reference to PMR or TA in this
article, or the use of steroids. I have had some experience of visual
hallucinations in the very elderly completely resolved with oral steroid
use.
Competing interests:
None declared
Competing interests: No competing interests
Dear Sir,
I read with interest the case report of a patient with Charles-Bonnet
syndrome. The authors conclude in their lesson that "not all elderly
people presenting with visual hallucinations have dementia". The
definition of dementia has evolved over the years with the increasing
recognition of isolated and subtle memory deficits as a presenting feature
in many patients long before other cognitive domains are affected but a
dementing illness presenting only with isolated visual hallucinations with
no other behavioural problems and intact cognitive domains would be very
unusual. Certainly in this context, a diagnosis of dementia would be
clinically incorrect. The lesson should therefore read"not all elderly
people with visual hallucinations have dementia"
SH Guptha
Ref:
1) Anu Jacob, Sanjeev Prasad, Mike Boggild, Sanjeev Chandratre. Charles
Bonnet syndrome—elderly people and visual hallucinations.BMJ 2004;328:1552
-1554
Competing interests:
None declared
Competing interests: No competing interests
Eneucleation Patients
Thank you for your great article. I had an eneucleation of my left
eye fifteen years ago due to ICE syndrome. I used to have fireworks that
would rival any new years eve and I see bizarre faces when I am going off
to sleep or when I meditate. Occasionally I see The faces of my deceased
parents and that warms me. Look at Lost Eye.com and you will see some
stories from my one eyed pals. Finally I can relax and thanks for giving
me my sanity back. Regards Rosalie Winter
Competing interests:
None declared
Competing interests: No competing interests