neglect

Question 1

What is the concept of “reverse engineering” the brain in neuropsychology?

Answer 1

“Reverse engineering” refers to inferring the function of a specific brain region by observing the effects on cognition or behavior after damaging or removing that region. It involves understanding how the brain works by studying the consequences of its disruption.

Question 2

Can you give an example of “reverse engineering” in neuropsychology?

Answer 2

A stroke resulted in a patient being unable to recognize fruit, animals, or trees but could recognize tools, vehicles, and furniture. This suggests that living versus non-living objects are represented differently in the brain.

Question 3

What does damage to a specific brain region tell us about its function?

Answer 3

If damage to a brain region disrupts one function (e.g., reading) but not others (e.g., speaking or seeing), it suggests that the region is specialized for the disrupted function.

Question 4

What is neglect in the context of neuropsychology?

Answer 4

Neglect is defined as “a failure to report, respond, or orient to novel or meaningful contralesional stimuli” (Heilman et al., 1985).

Question 5

What are some common behaviors of patients with neglect?

Answer 5

Patients may shave or apply makeup to only one side of their face, eat off one side of the plate, read only one half of the page, bump into walls, and be unaware of their difficulties (anosognosia).

Question 6

What is the most common cause of neglect?

Answer 6

The most common cause of neglect is a stroke affecting the right side of the brain.

Question 7

Which brain area is most associated with neglect?

Answer 7

The parietal lobe on the right side of the brain is most commonly associated with neglect in patients.

Question 8

What is the line bisection task used for?

Answer 8

The line bisection task involves marking the midpoint of a line and is used to assess neglect.

Question 9

What can a line bisection task reveal about a patient with neglect?

Answer 9

A patient with neglect may miss marking the left side of the line, indicating attention deficits in the left visual field or left side of space.

Question 10

What other tests are used to assess neglect?

Answer 10

In addition to the line bisection task, other tests for neglect include picture copying and cancellation tasks.

Question 11

What does a cancellation task assess in patients with neglect?

Answer 11

A cancellation task involves identifying and crossing out target stimuli (e.g., letters or shapes) in an array. It is highly sensitive in detecting neglect, especially when the array is more crowded.

Question 12

How does neglect affect vision or visual perception?

Answer 12

Neglect is not just a problem with vision or visual perception. A patient who is blind in one eye can still be aware of stimuli on the left side of their visual field, unlike a neglect patient who ignores the left side altogether.

Question 13

What is the significance of recovery from neglect?

Answer 13

Neglect usually recovers spontaneously within weeks or months, as seen in the self-portraits of German artist Anton Raederscheidt after his stroke.

Question 14

How does neglect operate in different frames of reference?

Answer 14

Neglect operates not only in egocentric (self-centered) reference frames but also in object-centered reference frames, meaning patients may neglect parts of objects even if those parts are not on their egocentric left.

Question 15

How does neglect affect object-centered processing?

Answer 15

Neglect patients may neglect the left side of an object’s dominant axis, even if it is not on their “egocentric” left side.

Question 16

What is the task involving a central triangle gap, and how does neglect affect performance?

Answer 16

In this task, patients must detect a gap in the central triangle. Patients with neglect may miss the gap if it appears on the left side of the object’s axis, even though the gap is at the center of fixation.

Question 17

What does the “blind-sight” phenomenon suggest about neglect?

Answer 17

The “blind-sight” phenomenon in neglect patients suggests that unconscious processing can influence action and decision-making, even when the patient is unaware of stimuli.

Question 18

How do neglect patients perform in tasks involving visual imagery?

Answer 18

Neglect patients may also show neglect for visual imagery, as demonstrated by Bisiach’s “Milan Square” experiment, where patients neglect parts of an imagined scene similar to how they neglect physical stimuli.

Question 19

What is the difference between neglect and extinction?

Answer 19

Extinction is a milder form of neglect that occurs when two or more objects are presented simultaneously, and one object is “extinguished” or ignored.

Question 20

How do patients with extinction perform on visual field tasks?

Answer 20

Patients with extinction may fail to report stimuli in their left visual field when presented with competing stimuli in the right visual field, even though they can report the left-side stimulus when presented alone.

Question 21

What does the “extinction” phenomenon tell us about neglect?

Answer 21

Extinction suggests that neglect is related to attentional deficits rather than purely perceptual ones, as patients fail to process stimuli when they compete for attention.

Question 22

What non-spatial deficits are often found in neglect patients?

Answer 22

Neglect patients often have poor working memory, a larger and longer “attentional blink,” and problems with sustained attention.

Question 23

What is the “attentional blink,” and how does it affect neglect patients?

Answer 23

The attentional blink refers to the inability to identify two targets presented in quick succession. Neglect patients often fail to detect the second target, especially if it appears shortly after the first.

Question 24

How does neglect affect sustained attention?

Answer 24

Neglect patients often struggle with sustained attention, as demonstrated by poor performance in tasks requiring them to maintain focus over time.

Question 25

What does neglect tell us about visual processing and attention?

Answer 25

Neglect reveals that attention operates in multiple spatial and object reference frames, and significant processing can occur even in the absence of awareness.

Question 26

How does neglect affect visual imagery?

Answer 26

Neglect patients process visual imagery similarly to incoming sensory information, showing neglect for parts of the image as if it were an external object.

Question 27

What is the overall conclusion about neglect from neuropsychological research?

Answer 27

Neglect is a disorder of attention that usually results from damage to the right parietal lobe. It involves inattention to the left side of space and objects, affecting both sensory perception and mental representations.