Charles Bonnet Syndrome (CBS) is a condition in which mentally healthy patients have vivid, complex, recurring visual hallucinations. This usually affects patients who have become (severely) visually impaired later in life. The syndrome was described by Swiss naturalist Charles Bonnet in 1760, when he documented his 89-year-old grandfather, who had become nearly blind in both eyes due to cataracts. However, he saw men, women, birds, carriages, buildings, tapestries when this was physically impossible. Bonnet also suffered from the same syndrome towards the end of his life. The English psychiatric literature introduced Bonnet syndrome in 1982. The syndrome is still relatively unknown in the medical world.
- Epidemiology Bonnet syndrome
- Causes of Bonnet syndrome
- Symptoms: Seeing visual hallucinations
- Diagnosis
- Therapy
- Tips for patients
- Brain disorder prognosis
Epidemiology Bonnet syndrome
The incidence of Bonnet’s syndrome is reported to be variable in scientifically based studies. The high incidence of non-reporting of this condition is the greatest barrier to determining its exact prevalence. Patients are afraid of being diagnosed with a psychiatric illness. They also think that the doctor will label them as crazy. The prevalence of Charles Bonnet syndrome is between 10% and 60%. The condition then occurs in approximately 10-15% of patients with moderate visual impairment. CBS syndrome is present in up to 60% of severely visually impaired patients. It is unknown whether CBS occurs more often in men or women. There is no clarity about this in the scientific literature. Although the syndrome is clearly associated with the elderly, cases in children have also been reported. The syndrome is also associated with lower visual acuity, but on the other hand, there are patients with, for example, glaucoma (medical term for “increased eye pressure”) who still have good visual acuity, and yet suffer from Bonnet’s syndrome.
Causes of Bonnet syndrome
CBS occurs most often in mentally healthy elderly people, probably due to the high prevalence of eye disorders in this group. The cause of this condition lies in the brain and is similar to phantom pain in which a person continues to have sensation and even receives pain signals when a leg has been amputated. The brain stores all kinds of visual memories and images. In CBS, retinal cells can no longer receive and transmit visual images from the brain as a result of an eye disease or optic nerve damage because, for example, the rods and cones die. Therefore, the cells compensate for this by creating their own phantom images.
Symptoms: Seeing visual hallucinations
The main symptom of this condition is visual hallucinations.
CBS often occurs in silence or in a state of rest. This happens, for example, after a meal or when listening to the radio (but not when dozing off). The hallucinations always outside the body. They are purely visual with no other senses involved. The hallucinations have no personal meaning for the patient. Hallucinations can last seconds, minutes or hours. Symptoms often occur when there is little light. The nature of the hallucination depends on the part of the brain that is active. The hallucinations can be black and white or in color. Patients can perceive lattice patterns, but often they see more complex images. The following images are possible:
- Images of complex colored patterns and images of patients are most common, followed by animals, plants or trees, and inanimate objects. The hallucinations often fit into the patient’s environment.
- Figures (often children), faces, wild animals and moving vehicles. In addition, recognizable patients, including deceased, have been reported.
- Texts or letters, but usually reading these documents is impossible when they try to do so.
Diagnosis
Making the diagnosis is sometimes difficult and the doctor often misses it. The diagnosis is made by excluding other conditions in which visual hallucinations (seeing unreal images) may occur. For example, some side effects of medications also cause visual hallucinations. If there are additional problems or neurological symptoms such as memory loss, weakness or tremor (tremors), the doctor will refer the patient to a neurologist. This rules out other conditions that may contribute to the hallucinations. This syndrome is still relatively unknown to doctors because patients do not often report it out of shame and fear.
Therapy
There is no proven effective treatment available for Charles Bonnet syndrome. The best treatment is to reassure the patient , with the doctor encouraging the patient to talk about this with family and/or others. Naturally, emotional support is very important so that the patient feels understood. Sometimes tranquilizers and psychological support are required for depression. A good sense of humor helps you adapt more easily to CBS. Family and healthcare workers confirm the bizarre hallucinations in a light-hearted manner . Jokes are allowed, but only if the patient finds them amusing. Relaxation techniques also help in dealing with the hallucinations. In addition, the doctor informs the patient that the hallucinations have no psychological meaning . They are not the product of the past, trauma, or unresolved feelings. In other words, there is no deeper meaning behind the hallucinations.
It is important that the patient regularly visits an ophthalmologist to have their eyes checked. The ophthalmologist can then detect and/or treat (underlying) eye disorders in a timely manner. The ophthalmologist may correct eye problems so that symptoms of Charles Bonnet syndrome disappear.
Tips for patients
Some tips to eliminate or reduce the hallucinations work for some patients with CBS. These tips do not always help or for everyone, but they are worth a try:
- darken or illuminate the room
- blinking
- go to the image or hallucination
- shouting at the image or hallucination
- hitting the image or hallucination
- staring at the hallucinations or moving/walking away
- looking from left to right about once per second for fifteen to thirty seconds without moving the head; the eyes must always remain open during the movements
- concentrating on something else / seeking distraction
Brain disorder prognosis
Some patients with the brain disorder suffer from the syndrome for years, while others only suffer from it for a few weeks or months. The brain then gradually but surely adapts to the reduced vision. Scientific studies report that CBS syndrome disappears in most cases after twelve to eighteen months.
read more
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