Visual Hallucinations in the Elderly

Bill Yates
Brain Posts

Posted 20th September 2009

Oliver Sacks presented a TED talk related to the phenomenon of visual hallucations in the elderly known as the Charles Bonnet syndrome.

In the case history, he describes an elderly woman who has been blind for 5 years due to macular degeneration. She has the sudden onset of seeing people in eastern dress, deformed faces with abnormal teeth. Additionally she reports seeing blue and red squares.

Sacks goes on to note that hallucinations are common in elderly patients---10% of deaf elderly patients have auditory hallucinations, 10% of blind elderly patients report visual hallucinations. The visual hallucinations of the elderly as described in the Charles Bonnet syndrome have the following characteristics:

1. Occur in the context of acquired visual impairment
2. Limited to visual sensations
3. Common content: deformed people, objects in mid-air, cartoons
4. Like a silent movie, but no specific meaning of interpersonal content

Neuroimaging studies of patients with Charles Bonnet syndrome note that lack of external visual input can result in occipital cortex hyperactivity (cortical release phenomenon). Patients may then experience to the visual hallucinations of the Bonnet syndrome.

Explaining the benign nature of the condition can often be helpful, as patients may assume the symptoms are due to emerging mental disorders.

Hat tip to Mind Hacks

Reference: Kazui H et al:Neuroimaging studies in patients with Charles Bonnet Syndrome. Psychogeriatrics. 2009 Jun;9(2):77-84.

Reference Abstract


Standard YouTube License @ TED

See the original article:

Visual Hallucinations in the Elderly

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