LETTER TO THE EDITOR Charles Bonnet syndrome and dementia Ng B, Smith D. Charles Bonnet syndrome and dementia. Acta Neuropsychiatrica 2004: 16:181–182. # Blackwell Munksgaard 2004 Bradley Ng, Daniel Smith Department of Psychiatry, Rotorua Hospital, Rotorua, New Zealand. Correspondence: Dr Bradley Ng, Department of Psychiatry, Rotorua Hospital, Private Bag 3023 L, Rotorua, New Zealand. Tel: þ 64-(0)7- 348-1199; Fax: þ 64-(0)7-349-7883; E-mail: Bradley.Ng@lakesdhb.govt.nz To the Editor: We read with interest the case described by Hori et al. (1) of a visually impaired 89-year-old woman with symptoms suggestive of Charles Bonnet syndrome (CBS), which is characterized by visual hallucinations and partial insight in the absence of other psychotic symptoms (2). The need for decreased visual acuity remains controversial (3). The patient’s MMSE score was 18 but the authors concluded that this only indicated mild cognitive impairment and she was not demented. Such a conclusion should be reached cautiously, given that such a score usually indicates significant cog- nitive impairment and no further neuropsych- ological testing was presented by the authors. According to the criteria (4), we would suggest that the patient has a possible Lewy body demen- tia (LBD), given her cognitive impairment and visual hallucinations, and that this diagnosis would override a diagnosis of CBS. Furthermore, atypical antipsychotics may have a role in the treatment of CBS in addition to donezepil (5). We describe an 82-year-old man who presented with 3 years of seeing people on his farm and around his house conducting various religious festivals. He also saw dogs and cats that he knew were not there because his hand went through them when he tried to touch them. There were no other psychotic or affective symp- toms and he retained partial insight into his condition. There was no past psychiatric history, but his brother had possible Alzheimer’s dementia. He had had a left cataract treated 2 years pre- viously, but retained good visual acuity in his right eye. He had also been diagnosed with mild Parkinson’s disease 1 year previously, after pre- senting with a right arm tremor and bilateral cog- wheel rigidity, but had declined pharmacological treatment. When he presented with his hallucin- ations, he also reported difficulties swallowing, and on examination had bradykinesia and a decreased arm swing. He scored 26 on MMSE, scoring 10/10 orientation, 4/5 concentration, 3/3 registration and 2/3 on 5-min recall. On attention span he was able to recall six digits forward and five backwards, and the clinical interview and cog- nitive screening revealed no evidence of executive dysfunction. He was prescribed 1 mg/day risperi- done and his visual hallucinations ceased without any deterioration of his Parkinson’s disease. A diagnosis of CBS and mild Parkinson’s disease was appropriate given the patient’s physical status, the severity of both conditions and the lack of other physical, psychiatric or cognitive features. Alcantara et al. (6) have emphasized that the diag- nosis of CBS should be made when there are visual hallucinations both before the motor signs of Parkinson’s disease and in the absence of anti- Parkinsonian treatment, which occurred in the above patient. We agree with Hori et al. (1) and Terao and Collinson (7) that clinicians should be vigilant for the emergence of either Alzheimer’s dementia (AD) or LBD. However, once the diag- nosis of AD or LBD is considered clinically to be either a probability or a possibility, the diagnosis of CBS should be subsumed under an appropriate dementia diagnosis. References 1. HORI K, INADA T, SENGAN S, IKEDA M. Letter to the editor. Acta Neuropsychiatrica 2003;15:102. 2. GOLD K, RABINS PV. Isolated visual hallucinations and the Charles Bonnet syndrome. A review of the literature and presentation of six cases. Comp Psychiatry 1989;30: 90–98. 3. TEUNISSE RJ, CRUYSBERG JR, HOEFNAGELS WH et al. Visual hallucinations in psychologically normal people: Charles Bonnet’s syndrome. Lancet 1996;347:794–797. 4. MCKEITH IG, GALASKO D, KOSAKA K et al. Consensus guidelines for the clinical and pathologic diagnosis of Blackwell Munksgaard 2004: 16: 181–182 Copyright # Blackwell Munksgaard 2004 Printed in Denmark. All rights reserved ACTA NEUROPSYCHIATRICA # Blackwell Munksgaard, Acta Neuropsychiatrica, 16, 181–182 181 https://www.cambridge.org/core/terms. https://doi.org/10.1111/j.0924-2708.2004.00066.x Downloaded from https://www.cambridge.org/core. IP address: 3.236.55.199, on 17 Jun 2020 at 17:49:46, subject to the Cambridge Core terms of use, available at