Disorders of Visual Perception

Question 1

What is meant by brain neglect?

Answer 1

-A failure to report, respond, or orient to novel or meaningful stimuli presented to the side opposite a brain lesion, when this failure cannot be attributed to either sensory or motor defect

Question 2

what is this brain neglect also referred to as?

Answer 2

• hemi-neglect
• visual neglect
• visuo-spatial neglect
• unilateral neglect

Question 3

What is visual consequence of brain neglect?

Answer 3

• only partial visual image is registered

- eg half a plate of food

Question 4

What medical condition can induce brain neglect?

Answer 4

-stroke

Question 5

Names for 4 type of neglect

Answer 5

• sensory
• motor
• spatial
• personal

Question 6

How do all these types of neglect vary?

Answer 6

-vary in how aware patients are in their neglect

Question 7

Examples. of everyday neglect

Answer 7

• draw portions of a picture
• shave / apply make-up to only half their face
• dress only one side of their body
• eat food on only one side of their plate
• read part of a word or sentence

Question 8

What is personal neglect and how does it arise?

Answer 8

• A lack of orientation or exploration of the side of the body contralateral to the injured hemisphere

Question 9

What is extra personal neglect and how does it arise?

Answer 9

-A failure to detect visual and auditory stimuli on the contralesional side

Question 10

What are the 4 ways of assessing neglect?

Answer 10

• Cancellation tasks
• Line bisection
• Copy drawing or draw from memory
• The Personal Neglect Test

Question 11

What is the personal neglect test scale?

Answer 11

• 0 = the patient promptly reaches for the target.
• 1 = the target is reached with hesitation and search.
• 2 = the search is interrupted before the target is reached.
• 3 = no movement towards the target is performed

Question 12

What is the neuroanatomy of neglect?

Answer 12

• Strong association with right hemisphere lesions (damage to left side of the brain)
• damage to parietal lobe
• damage to frontal lobe
• damage to sub-cortical regions

Question 13

What insight does brain neglect give?

Answer 13

-likely to be a hemispheric asymmetry

Question 14

What is meant by hemispheric asymmetry?

Answer 14

-right hemisphere is more specialised for attention than the left

Question 15

Is neglect just a visual defect?

Answer 15

• no, representation of the world is defective
• ability to recall this imagery is hindered
• ability to see it is not the issue

Question 16

What is attention?

Answer 16

-Selection of information for conscious processing and action – the ‘spotlight’ idea

Question 17

What are the three attentional accounts of neglect?

Answer 17

• Impaired orienting of attention to neglected side
• Overly strong orienting of attention to non-neglected (intact) side
• Impaired disengagement of attention once it is oriented to the non-neglected (intact) side

Question 18

What is the suggested intended purpose of parietal lobes?

Answer 18

-perhaps to disengage attention

Question 19

Why does patient not want to be in house that is half burning even though they can’t perceive it?

Answer 19

• Suggests that the information is being processed at an early stage (bottom-up)
• There is a problem with selective attention at a higher stage of processing (top-down

Question 20

What are two key factors in awareness?

Answer 20

• Mental representations

- Attentional mechanisms

Question 21

How long for brain to consciously process image?

Answer 21

-180ms

Question 22

How long for unconsciously. process sensory information?

Answer 22

-30ms