charles bonnet syndrome


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charles bonnet syndrome

  1. 1. Visual hallucinations in low vision patientsBehrouz MalekiBSc of OptometryMSc & PhD student of PsychologyCharles Bonnets syndrome
  2. 2. 5/20/2013Visual hallucinationsin psychologically normal peoplewho have lost vision
  3. 3. 5/20/2013Illusionmisinterpreting real objectsHallucinationperception of an external object when no such object is presentDelusionbeing convinced that what the perceived hallucinations are real
  4. 4. 5/20/2013In about 1760, Charles Bonnet, aSwiss naturalist and philosopher,described the vivid hallucinationsexperienced by his 87-year-oldgrandfather.In 1936 de Morsier (whom, likeCharles Bonnet, was a native ofGeneva Switzerland), named thephenomenon after Charles Bonnet.
  5. 5. 5/20/2013• CBS is not a well known condition, but is a common one. (at least10%-15% of patients with visual loss are affected)• Unfortunately some health professionals are not aware it.• CBS occurs frequently in elderly, visually handicapped patients.• People live longer• According to UN reports world’s population is aging rapidly(median age of Iranians have raised to 27 years in 2010, up from21 years in 2000. The median age could reach 40 years by 2030.)
  6. 6. 5/20/2013• Considerable under-reporting• 10%-15% of patients with moderate visual loss• Up to 50% of people with severe visual loss• Can affect the young as well as the old• But most patients are elderly (mean age: 70 to 85 years)
  7. 7. 5/20/2013• Hallucinations may interfere with daily life andnegatively impact quality of life•Anger•Worry that the hallucinations are caused by mentalillness, Anxiety• Depression and social isolation
  8. 8. 5/20/2013• Occur in a “state of quiet restfulness”• Start without warning, last for a few minutes or for several hours• Are very detailed, and much clearer than patient’s current vision• Interact and conform to actual surroundings• Make eye contact with the viewer• Always outside the body• Patient knows they are not real• Have no personal meaning to the patient• Are pleasant expressions
  9. 9. 5/20/2013• Simple repeating patterns:patterns, dots, shapes or lines which can form into more complicatedpatterns such as brickwork, network of branches, mosaic or tiles or seeingdifferent patterns on people’s clothing.(clear description of the shape or position of the image)• Complex hallucinations:hallucinations of people, animals, objects, texts or letters, moving vehiclesand landscapes.• Both types of hallucination may occur simultaneously or subsequently
  10. 10. 5/20/2013
  11. 11. 5/20/2013Risk factors include:• vision impairment (especially from ARMD)• old age• hearing impairment• living alone• very little social interaction
  12. 12. 5/20/2013loss of vision from an eye condition:• Age-related macular degeneration (ARMD)• Cataract• Glaucoma• Diabetic retinopathy and other Retinal disorders with vision loss• Choroidal neovascularization• Visual field defects following stroke or neurosurgery• Bilateral optic nerve damage due to methyl alcohol poisoning• Vision loss from retinopathy of prematurity (ROP)
  13. 13. 5/20/2013Sensory deprivation (deafferentation) theory:321 Ocular lesionReduced sensory input to the brainVisual brain struggles to make sense ofthe fragments it has seen4Displaying images which are stored orself produced
  14. 14. 5/20/2013
  15. 15. 5/20/2013Sensory deprivation (deafferentation) theory:• After a time, the visual brain readjusts to its new level of stimulation from theeye and the spontaneous firing of cerebral neurons diminishes.• 13 normally sighted patients• were blindfolded for 5 days• 10 of these patients reported hallucinations after an average of 1 day
  16. 16. 5/20/2013Main diagnostic criteria:Visual Loss:• Any type or degree of visual loss• Poor vision in both eyes• Occurs around the time of vision lossRecurrent Visual hallucinations:• At least one hallucination within the past month• Period between the first and the last hallucination must exceed one month• No hallucinations in other sensesInsight:• Normal cognitive status• Full or partial Insight into the unreal nature of the hallucinations• No delusions
  17. 17. 5/20/2013Simple hallucinations:• Ocular disease (e.g. retinal detachment)• Neuro-ophthalmic disease (e.g. optic neuritis)• Neurological disease (e.g. migraine, occipital lobe tumors)Complex hallucinations:Psychiatric diseases and neurologic diseases:• Drug-intoxication states and drug-withdrawal states• Adverse effect of medication• Schizophrenia and other psychotic mental illness• Delirium• Dementia• Alzheimers disease (AD)• Parkinson disease• Strokes and other brain conditions, which affect visual brainPatients with difficulty with mentation, poor insight, numbness, tingling,weakness on one side of the body other neurologic or systemic signs orsymptoms should be referred for psychiatric or neurologic evaluation
  18. 18. 5/20/2013The saying "This, too, shall pass" is almost true for those with CBS.For many, the symptoms subside after about 18 months
  19. 19. 5/20/2013• Every health care practitioner should be educated about CBS.• The eye care professional is the best healthcare professional to diagnose thiscondition• It is advised to discuss CBS with any patient whose visual acuity is 20/100 or20/200 in both or the better eye• CBS patients should be encouraged to talk about their hallucinations• The professionals in the mental health field are the experts at helping peopledeal with hallucinations, depression or anxiety
  20. 20. 5/20/2013Forewarning and education• Forewarning the possibility of hallucinations helps patients cope as they occur• Nature of these hallucinationsEmpathy and reassurance• It is a functional problem with their sight, not a problem with their mind• It is a normal occurrence in many visually-impaired people (Normalizing)• The condition usually improves with timePractical changes to lifestyle and Home modification• Improving vision by improving lighting or the use of optical devices• Physical condition (e.g. not smoking and avoiding sun exposure to the eyes)• Getting enough rest and having enough sleep• Reducing causes of and increasing coping skills around stress• Find ways to reduce social isolation and lack of stimulation
  21. 21. 5/20/2013Is this too detailed to be real?Having a good knowledge of your surroundingsDistracting the brain• Having the TV or radio on• moving around a little• standing up• Walk away from the hallucination or reaching out towards it• Closing and opening your eyes, blinking and eye exercises• Staring at or fixating on the image• Holding breath• Even feeling a dice with dimplesPharmaceutical treatment should only be considered in patients:• Experiencing distressing hallucinations• Cannot tolerate these despite non-pharmaceutical approaches
  22. 22. 5/20/2013With special thanks to KOA