Disorders of Attention (oct 18/20)

Question 1

Describe contralateral neglect in terms of behavior.

Answer 1

1. Behaviour
   - deficits in attending to and reporting on objects in space that is opposite the lesion; spatial bias for directing eye movements and actions towards into ipsilensional space.
   - not explained by low level visual or motor problems; instead, the saliency of contralesional objects is affected.
   - commonly features anosognosia.

Question 2

Describe Balints syndrome in terms of behaviour

Answer 2

1. Simultanagnosia
   - Only can put attention on one object or event at a time
   - Constriction of visual window of attention.
   (Story about the action story)
2. Oculomotor Apraxia
   - Problems initiating eye movements
   - damage of saccade planng areas in parietal cortex (planning)
   - Cannot move attention to move the eyes.

3.Optic Ataxia
- Disorder of visually-guided reaching, especailly with the contralesional hand.
- Damage to the superior parietal lobe.

Question 3

Describe Balints syndrome in terms of brain dysfunction

Answer 3

• A severe disruption of attention based on a large region of brain damage
• Bilateral damage to the parieto-occiptal lobes due to stroke, some dementias, TBI, some trauma, neurodegenerative.
• primary sensory processing, language, memory and judgement intact.

Question 4

Describe Balints syndrome in terms of treatment.

Answer 4

No standard treatment program exists.
- coping strategies can help but neurological change is difficult or impossible beacuase of the distribution of brain damage.

Question 5

List 2 other conditions that are related the visuospatial attention near the body.

Answer 5

PPS is proritzed by the attention system = peripersonal space.
1. Having a large PPS can correlate with anxiety or claustrophobia
2. having a small one can correlate with autism and schizophrenia.

Question 6

What is visuospatial attention?

Answer 6

Selectively processing one physical location in space to the exclusion of others.

Question 7

What is the Posner cueing task? What does it show us? How does it help study visuospatial attention? what is inhibition to return?

Answer 7

• With the cross and the 2 squares on the side there is first a cue and then an x, you clap when you see the x.
• uncued people gradually get better at clapping closer to when the x appears (with onset time getting larger), however it is the same with the cue but with a larger onset time around 300 we get worse; this is called inhibition to return.
• comparing reaction times across these two trial types allows us to study visuospatial attention at a particular location in healthy and dysfunctional people.

Question 8

what is pseudoneglect?

Answer 8

Typical performance in non-brain-damaged individuals shows a slight bias to the left because the right hemishere’s dominance in processing space. This is pseudo-neglect.

Question 9

Why is neglect so lateralized?

Answer 9

Throught that right parietal corte represents both sides of space while left parietal cortex monitors only the right. So if the right side is damaged and it was the only thing attending to the left then there is nothing attending to it.

Question 10

When do subcortical injuries lead to neglect?

Answer 10

Cortical hypoperfusion predicts neglect (when in the right hemisphere)
- subcortical injuries lead to neglect to the extent that they affect blood flow to the cortex.

Question 11

What are the 2 types of neglect and how do they differ?

Answer 11

1. Egocentric - only paying attention to the right side of the whole field of vision.
2. Object centred neglect - only paying attention to the right side of objects in the field of vision.

Question 12

what are some signs of recovery for neglect?

Answer 12

1. Allesthesia
   - responding to stimuli on the neglected side as though they were on the non-neglected side.
   - mislocating stimulus.
2. Simultaneous extinction
   - responding to stimuli on the neglected side unless both sides are stimulated simultaneously, then they only notice the ipsilateral stimulus.

Question 13

Describe contralateral neglect in terms of brain dysfunction

Answer 13

2. Brain Dysfunction
   - almost always right-right damage leading to left-side neglect.
   - 3 major cortical areas
   a) Inferior parietal lobe and temporo-parietal junction
   b) superior temporal gyrus
   c) ventral frontal cortex.
   These are involved in spatial orienting.
   - Dammage to white matter tracts connecting the three sites (and to the sites themselves can also lead to neglect.
   - Cortical hypoperfusion predicts neglect (when in the right hemisphere)
   - subcortical injuries lead to neglect to the extent that they affect blood flow to the cortex.

Question 14

Describe contralateral neglect in terms of treatment

Answer 14

Prismatic adaptation
- Wearing prism goggles is training/intervention and then they get better without them.
- the goggles make our shift your focus to the right more than normal so you are forced to shift to the left for when doing tasks.
- overtime there is evidence that this ca work.

VR reaching practice
- forces people to use neglected side of the body
- VR group showed improvements on the star cancelation exercise than the control.

Transcranial Magnetic Stimulation
- low frequency to the non-injured left side of the brain to increase right side activity.