0
Get Alert
Please Wait... Processing your request... Please Wait.
You must sign in to sign-up for alerts.

Please confirm that your email address is correct, so you can successfully receive this alert.

1
Letter   |    
Visual Hallucinations in Alzheimer's Disease: Possible Involvement of Low Visual Acuity and Dementia With Lewy Bodies
Takeshi Terao, M.D., Ph.D.
The Journal of Neuropsychiatry and Clinical Neurosciences 2000;12:516-517. doi:10.1176/appi.neuropsych.12.4.516
View Author and Article Information

HallucinationsAlzheimer's DiseaseBonnet Syndrome

SIR: I read with interest the article by Holroyd et al.1 where they showed that Alzheimer's disease (AD) patients with visual hallucinations had a significantly smaller occipital/whole brain ratio than AD patients without visual hallucinations. Although they mentioned limitations to their study such as small sample size, there are another two limitations as follows.

First, low visual acuity may be associated with visual hallucinations in AD patients. For example, Chapman et al.2 have reported that only impaired visual acuity was entered into the equation when logistic regression analysis examined cognition, visual acuity, and gender as associates of visual hallucinations in AD patients. Accordingly, it is necessary to compare visual acuity between AD patients with visual hallucinations and those without them in the patients of Holroyd et al.1 If the two groups had comparable visual acuity, their visual hallucinations might have derived from neuropathology of the occipital lobe. However, if AD patients with visual hallucinations had significantly lower visual acuity, it is uncertain whether their visual hallucinations derived from low visual acuity or from neuropathology of the occipital lobe or both. Actually, even psychologically normal old people can suffer from visual hallucinations, which is called Charles Bonnet syndrome.3,4

Second, although Holroyd et al.1 diagnosed probable AD according to NINCDS-ADRDA criteria, there is a possibility that their patients included patients suffering from dementia with Lewy bodies (DLB) because AD+DLB patients are not easily distinguished clinically from pure AD cases.5 Moreover, visual hallucinations occur at significantly higher rates in DLB patients than in AD patients.5,6 If Holroyd and colleagues'1 group of probable AD patients with visual hallucinations actually included more DLB patients than their AD group without visual hallucinations, DLB rather than occipital atrophy might have been associated with visual hallucinations.

Holroyd S, Shepherd ML, Downs JH: Occipital atrophy is associated with visual hallucinations in Alzheimer's disease. J Neuropsychiatry Clin Neurosci  2000; 12:25—28
[PubMed]
 
Chapman FM, Dickinson J, McKeith I, et al: Association among visual hallucinations, visual actuity, and specific eye pathologies in Alzheimer's disease: treatment implications. Am J Psychiatry 1999; 156:1983—  1985
 
Teunisse RJ, Cruysberg JR, Hoefnagels WH, et al: Visual hallucinations in psychologically normal people: Charles Bonnet's syndrome. Lancet  1996; 347:794—797
[CrossRef] | [PubMed]
 
Terao T: Effect of carbamazepine and clonazepam combination on Charles Bonnet syndrome: a case report. Hum Psychopharmacol Clin Exp  1998; 13:451—453
[CrossRef]
 
Luis CA, Barker WW, Cajaraj K, et al: Sensitivity and specificity of three clinical criteria for dementia with Lewy bodies in an autopsy-verified sample. Int J Geriatr Psychiatry  1999; 14:526—533
[CrossRef] | [PubMed]
 
Ballard C, Holmes C, McKeith I, et al: Psychiatric morbidity in dementia with Lewy bodies: a prospective clinical and neuropathological comparative study with Alzheimer's disease. Am J Psychiatry 1999; 156:1039—  1045
 
+

References

Holroyd S, Shepherd ML, Downs JH: Occipital atrophy is associated with visual hallucinations in Alzheimer's disease. J Neuropsychiatry Clin Neurosci  2000; 12:25—28
[PubMed]
 
Chapman FM, Dickinson J, McKeith I, et al: Association among visual hallucinations, visual actuity, and specific eye pathologies in Alzheimer's disease: treatment implications. Am J Psychiatry 1999; 156:1983—  1985
 
Teunisse RJ, Cruysberg JR, Hoefnagels WH, et al: Visual hallucinations in psychologically normal people: Charles Bonnet's syndrome. Lancet  1996; 347:794—797
[CrossRef] | [PubMed]
 
Terao T: Effect of carbamazepine and clonazepam combination on Charles Bonnet syndrome: a case report. Hum Psychopharmacol Clin Exp  1998; 13:451—453
[CrossRef]
 
Luis CA, Barker WW, Cajaraj K, et al: Sensitivity and specificity of three clinical criteria for dementia with Lewy bodies in an autopsy-verified sample. Int J Geriatr Psychiatry  1999; 14:526—533
[CrossRef] | [PubMed]
 
Ballard C, Holmes C, McKeith I, et al: Psychiatric morbidity in dementia with Lewy bodies: a prospective clinical and neuropathological comparative study with Alzheimer's disease. Am J Psychiatry 1999; 156:1039—  1045
 
+
+

CME Activity

There is currently no quiz available for this resource. Please click here to go to the CME page to find another.
Submit a Comments
Please read the other comments before you post yours. Contributors must reveal any conflict of interest.
Comments are moderated and will appear on the site at the discertion of APA editorial staff.

* = Required Field
(if multiple authors, separate names by comma)
Example: John Doe



Web of Science® Times Cited: 2

Related Content
Books
DSM-5™ Clinical Cases > Chapter 17.  >
The American Psychiatric Publishing Textbook of Geriatric Psychiatry, 4th Edition > Chapter 13.  >
The American Psychiatric Publishing Textbook of Geriatric Psychiatry, 4th Edition > Chapter 11.  >
Gabbard's Treatments of Psychiatric Disorders, 4th Edition > Chapter 11.  >
The American Psychiatric Publishing Textbook of Geriatric Psychiatry, 4th Edition > Chapter 13.  >
Topic Collections
Psychiatric News
Read more at Psychiatric News >>
APA Guidelines