A Case Report and Review: Charles Bonnet Syndrome Plus With Dementia

Charles Bonnet Syndrome (CBS) refers to visual hallucinations in visually impaired patients without psychiatric illness who are typically aware that their hallucinations are not real. Rare cases in the literature describe patients with atypical CBS, or CBS plus, who experience hallucinations in the context of sensory deficits but do not meet all of the criteria of a CBS diagnosis. These cases may include hallucinations in more than one sensory modality, including auditory hallucinations, which are thought to arise by a similar pathophysiology to that of the visual hallucinations in CBS. Unfortunately, the clinical criteria for atypical CBS are ambiguous, potentially explaining the rarity of the diagnosis. In addition, certain features of atypical CBS may make the condition particularly prone to misdiagnosis.

We report a case of atypical CBS in a 67-year-old white male patient presenting with visual and auditory hallucinations that were improved by reassurance. Alongside this case presentation, we provide a review of atypical CBS cases in the literature to compare the diverse features of the syndrome. For this review, we included cases of atypical CBS or CBS plus within the past 20 years for which we could obtain the full text.

Clearer guidelines for the diagnosis of atypical CBS and greater attention to the disorder could substantially improve the management of patients presenting with hallucinations. A broader differential diagnosis including atypical CBS for elderly patients with new-onset hallucinations could help clinicians and patients avoid unnecessary medical workup and treatment.