Conditions Affecting Perception

• What are some disorders of perception associated with dementia?

  Posterior cortical atrophy, dementia with Lewy bodies, and visual hallucinations associated with Parkinson’s disease.
• What topics are covered regarding conditions affecting perception?

  • Conditions affecting perception associated with dementia
  • Conditions affecting perception associated with sensory loss
  • Comparisons between congenital and acquired conditions
  • Insights from conditions affecting perception
• How is visual impairment related to dementia according to Marquie et al. (2019)?

  Visual impairment is commonly associated with dementia.
• What are some visual symptoms associated with Alzheimer’s Disease?

  Reduced contrast sensitivity, visual field defects, disrupted eye movements, reading difficulties, and difficulties in recognizing and locating objects.
• What is posterior cortical atrophy also known as?

  Benson’s syndrome.
• At what age does posterior cortical atrophy typically onset?

  Around 55-65 years old.
• What is a notable experience described by a patient with posterior cortical atrophy?

  The patient could not see a teacup in front of him despite being aware of its presence.
• What are some cognitive difficulties associated with posterior cortical atrophy?

  Constructional dyspraxia, agraphia/dysgraphia, apperceptive visual agnosia, anomia/dysnomia, prosopagnosia, and dressing apraxia.
• What are amyloid plaques and neurofibrillary tangles associated with in posterior cortical atrophy?

  They are abnormal accumulations that disrupt communication between neurons.
• How does degeneration in posterior cortical atrophy differ from that in Alzheimer’s Disease?

  Posterior cortical atrophy involves degeneration in the posterior cortical regions, while Alzheimer’s Disease affects areas like the hippocampus.
• What protein deposits are associated with dementia with Lewy bodies?

  Deposits of alpha-synuclein inside neurons.
• What type of hallucinations are commonly experienced by patients with dementia with Lewy bodies?

  Complex hallucinations featuring people or animals.
• How do patients with dementia with Lewy bodies perform on visual tasks compared to those with Alzheimer’s Disease?

  They perform more poorly on both simple and complex visual tasks.
• What are the main symptoms of Parkinson’s disease?

  Involuntary tremors, slow movement, and stiff and inflexible muscles.
• What percentage of patients with Parkinson’s disease experience hallucinations?

  40% of patients had a hallucination within the previous 3 months.
• What is Charles-Bonnet syndrome?

  • Visual hallucinations resulting from sight loss
  • Can include simple patterns or complex scenes
  • Named after Charles Bonnet, who documented his grandfather's experiences
• What does the sensory deprivation theory suggest about Charles-Bonnet syndrome?

  Loss of visual input leads to changes in excitability of the visual association cortex.
• What is phantom limb sensation?

  Sensation in a limb that is no longer there.
• What was the outcome of the mirror therapy study by Chan et al. (2007) for amputees?

  Mirror therapy led to a significant reduction in pain.
• What percentage of hearing impaired patients experienced auditory hallucinations according to Linszen et al. (2018)?

  16% of hearing impaired patients experienced auditory hallucinations.
• What is the difference between congenital and acquired conditions?

  • Congenital: present at birth or shortly after
  • Acquired: developed later, typically due to injury or illness
• What is cataracts?

  Clouding of the lens.
• What visual changes are associated with cataracts?

  Increased sensitivity to glare, reduced ability to perceive contrast, and blurring.
• How do congenital cataracts affect visual development?

  They can produce permanent abnormalities in the visual system if not removed quickly.
• How common are cataracts in older adults in England and Wales?

  Approximately 2.5 million people aged 65 or over have some degree of visual impairment due to cataracts.
• What is nystagmus?

  Involuntary wobble of the eyes.
• What is the difference between congenital and acquired nystagmus?

  Congenital nystagmus is present at birth, while acquired nystagmus develops later.
• How does a person with congenital nystagmus perceive the world compared to someone with typical sight?

  They do not experience their world moving around.
• What is oscillopsia?

  A sensation of the world moving around, often occurring in acquired nystagmus.
• What did Richardson et al. (2006) find regarding phantom limb sensations in amputees?

  All experienced sensations in the phantom limb, with 79% experiencing phantom limb pain.
• What was the likelihood of experiencing phantom limb sensations in patients born without limbs compared to those who had limbs amputated early?

  20% of those born without limbs and 50% of those with early amputations experienced phantom limb sensations.
• How do congenital and acquired conditions affect sensory system development?

  • Congenital conditions can lead to permanent abnormalities if not treated early.
  • Acquired conditions typically do not affect sensory development in the same way.
• What do differences between acquired and congenital conditions indicate about perception development?

  There is a critical period for perception to develop.
• How does damage to different areas of the brain affect perception?

  It results in different effects on perception, such as difficulties in visual object recognition.
• What do perceptual differences indicate about the interaction between sensory and brain systems?

  They indicate a complex interaction between sensory systems and the brain to produce perception.
• What have we learned about conditions affecting perception?

  • Changes in sensory organs or brain areas can alter perception.
  • Different conditions provide insights into brain organization.
  • Acquired and developmental conditions lead to different perceptual outcomes.