Disordered perception

Question 1

What is visual impairment in dementia?

Answer 1

Visual impairment is commonly associated with dementia. Some specific types of dementia are associated with particular difficulties in visual functioning. Marquie at al (2019) found ppts with dementia had worse acuity

Question 2

What are visual symptoms of Alzheimer’s disease?

Answer 2

Reduced contrast sensitivity, visual field defects, disrupted eye movements, reading difficulties and difficulties in recognising and locating objects

Question 3

What is posterior cortical atrophy?

Answer 3

(Bensons syndrome) rare form of dementia affecting posterior cortex, onset around 55-65 yrs. First signs are usually problems with vision and perception, and declines in memory and language occur later on

Question 4

What are similaritys of PCA and Alzheimer’s?

Answer 4

Amyloid plaques and neurofibrillary tangles in the brain

Question 5

What are amyloid plaques?

Answer 5

Abnormal levels of amyloid precursor protein clump together to form plaques. Collect between neurons and disrupt cell function

Question 6

What are neurofibrillary tangles?

Answer 6

Abnormal accumulations of tau proteins inside neurons. Disrupt communication between neurons

Question 7

What is a difference between PCA and Alzheimer’s?

Answer 7

In PCA, degeneration of posterior cortical regions (occipital lobe), whereas Alzheimer’s, degeneration in areas such as hippocampus

Question 8

What is dementia with lewy bodies?

Answer 8

Deposits of protein (alpha-synuclein) inside neurons. Symptoms include cognitive decline, movement problems and hallucinations (up to 80% of patients)

Question 9

What did Moismann et al (2006) look at?

Answer 9

Hallucinations are usually compex, featuring people or animals and experienced as unpleasant

Question 10

What did Moismann et al (2006) look at?

Answer 10

Hallucinations are usually complex, featuring people or animals and experienced as unpleasant

Question 11

What did Harding, Broe and Halliday (2002) find?

Answer 11

Those with visual hallucinations had higher densities of lewy bodies in the amygdala and parahippocampus thsn without hallucinations

Question 12

What did Harding, Broe and Halliday (2002) find?

Answer 12

Those with visual hallucinations had higher densities of lewy bodies in the amygdala and parahippocampus than without hallucinations

Question 13

What is Parkinson’s disease?

Answer 13

Characterised by difficulties in movement. Main symptoms are involuntary tremors, slow movement and stiff and inflexible muscles. Approximately 50-80% with Parkinson’s eventually experience Parkinson’s disease dementia

Question 14

What did Fenelon, Mahieux and Ziegler (2000) find?

Answer 14

40% patients with Parkinson’s had a hallucination within previous 3 months - visual and auditory

Question 15

What is Charles-Bonnet syndrome?

Answer 15

Visual hallucinations resulting from sight loss. Can be simple repeated patterns or shapes, or complex hallucinations of people, objects and landscapes.

Question 16

What is sensory deprivation theory linked with CBS?

Answer 16

Loss of visual input to brain leads to a change in excitability of visual association cortex. May occur due to increase in number of neurotransmitters released in presynaptic neuron due to increased vesicles or increase in number of receptors in postsynaptic membrane.

Question 17

What is phantom limb?

Answer 17

Sensation in a limb that is no longer there, occurring in a majority of amputees. Can be itches, twitches or pain and are virtually non-existent in congenital amputees

Question 18

What did Chan et al (2007) find?

Answer 18

Mirror therapy leads to s significant reduction in phantom pain compared to mental visualisation

Question 18

What did Chan et al (2007) find?

Answer 18

Mirror therapy leads to s significant reduction in phantom pain compared to mental visualisation

Question 19

What did Linszen et al (2018) find?

Answer 19

16% of hearing impairment patients experienced auditory hallucinations mostly consisting of voice (51%), music (36%) and doorbells or phones (24%)

Question 20

What is the difference between acquired vs congenital disorders?

Answer 20

Congenital - present at birth or shortly after
Acquired - acquired later on, typically as an adult

Question 21

What visual changes due cataracts cause?

Answer 21

More light required to do normal activities, increased sensitivity to glare, reduced ability to perceive colour and contrast, problems with depth perception and blurring

Question 22

What are congenital cataracts?

Answer 22

Unilateral cataracts usually have no known cause and brain will eventually ignore it, whereas bilateral cataracts are often inherited and visual development is limited. Removed quickly to avoid permeant damage. Affects around 4/10000 born in UK

Question 23

What is nystagmus?

Answer 23

Involuntary wobble of the eyes - most people have no visual impairment. Oscillopsia often occurs in acquired but not congenital nystagmus

Question 24

What is the difference between congenital and acquired nystagmus?

Answer 24

Congenital - present at birth or develops during early infancy, some forms inherited
Acquired - develops beyond early infancy, may result from stroke or head injury

Question 25

What did Richardson et al (2006) find?

Answer 25

60 amputees who experienced amputations, all experienced sensations in phantom limb 6 months after surgery, 79% experienced pain

Question 26

What are differences in diseases when they are congenital vs acquired?

Answer 26

Cataracts may produce permeant abnormalities if not removed when they’re congenital
Acquired nystagmus often develop oscillopsia but not congenital
Amputated limbs typically develop phantom sensations and pain, but not those born without limb

Question 27

What are critical periods?

Answer 27

Differenced between acquired and congenital disorders tell us that there is a critical period for perception to develop

Question 28

What does organisation of the brain impact?

Answer 28

Damage to different areas of the brain results in different impairments in perception

Question 29

What are the interactions between sensory and brain systems?

Answer 29

Disordered perception can happen at different stages of the perceptual process. Complex interactions between the sensory systems and the brain to produce perception