Lecture 4 Flashcards

1
Q

Attention deficitis

A
  • Balint’s syndrome = neuoropsychological disorder
  • Hemispatial neglect (neuropsychological disorder)
  • ADD/ADHD (developmental disorder)
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2
Q

What is neglect?

A

-Lack of awareness of stimuli presented to the opposite side to the brain damage

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3
Q

Ways to test for hemispatial neglect

A
  • Cancellation task = give patient lines on paper and get them to draw line across other line (X) –> Only put lines through half side of sheet
  • Line bisection = give patient a line, tell them to put line where middle is –> put towards right of line as unaware line carries on to the left
  • Copying abilities = only able to draw half drawings e.g. will draw a clock only from 1-7 but a full circle
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4
Q

Symptoms of neglect

A
  • Can ignore contralesional (opposite) side of imagined scenes
  • Can ignore left side of each object not left side of scene –> its often object directed
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5
Q

Extinction

A
  • Patients detect stimulus presented to one visual field but fail to detect same stimulus when another stimulus is presented to the other field at the same time –> suggests a competition mechanism - different perceptual representations are competing for attention = extinction
  • Found in patients suffering from neglect but can occur independently
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6
Q

How much is processed?

A
  • Patients with neglect cannot accurately identify objects presented to the neglected field
  • No conscious access of what they have seen
  • Object presented to the neglected field can change the patients behaviour
  • Meaning of object processed
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7
Q

How to explain neglect/extinction

A
  • Neglect and extinction are both deficits of attention not perception
  • Dorsal stream - endogenous attention (top-down)
  • Ventral stream - exogenous attention (bottom-up)
  • -> Associated with neglect
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8
Q

Lesions underlying neglect

A
  • Associated with damage to the right inferior parietal lobe
  • TMS on same regions produced neglect/extinction symptoms
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9
Q

Evidence for neglect/extinction

A
  • Neglect patients benefit from valid cues in both visual fields
  • Suggests endogenous orienting system is relatively intact in neglect patients
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10
Q

Disengagement of attention

A
  • Neglected patients most impacted when trying to disengage attention from intact side
  • Arrow pointing right + square right = unimpaired
  • Arrow pointing left + square left = slight impairment
  • Arrow pointing right + square left = large impairment
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11
Q

Neglect without brain injury

A
  • When dozing off, sounds played from left and right
  • Spatial attention shifts to the right as we get drowsy
  • Each cerebral hemisphere competes for attention
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12
Q

ADHD symptoms

A
  • Attention deficit hyperactivity disorder
  • Hyperactivity
  • Impulsivity
  • Inattention
  • Symptoms present childhood
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13
Q

Inattention symptoms of ADHD

A
  • Need at least 6
  • Poor attention to details
  • Difficulty in sustaining attention
  • Doesn’t appear to listen
  • Doesn’t follow instructions
  • Difficulty organising
  • Avoids tasks that require sustained effort
  • Looses things
  • Easily distracted
  • Forgetful
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14
Q

Hyperactivity and impulsivity symptoms of ADHD

A
  • Need at least 6
  • Fidgets
  • Leaves seat when expected to remain
  • Runs excessively
  • Difficulty in playing quietly
  • Always on the go
  • Talks excessively
  • Bursts out answers before question complete
  • Doesn’t wait their turn
  • Interrupts others
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15
Q

Causes of ADHD

A
  • Unknown
  • Main risk factors:
  • -> Genetics
  • -> Prenatal exposure to alcohol and tobacco
  • -> Post-natal prefrontal damage
  • -> Significantly low birth weight
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16
Q

Neurocognitive deficits of ADHD

A
  • Structural:
  • -> Reduced grey matter and cortical connectivity in the fronto-parietal attention network
  • Functional:
  • -> Hypoactivity in prefrontal cortex

-Imbalance in dopamine and noradrenaline circuits

17
Q

Medication for ADHD

A
  • Stimulants
  • Methylphenidate
  • Dextroamphetamine
  • Medications reduce symptoms by:
  • -> Blocking reuptake of norepinephrine and dopamine –>enhances NOR and DOP availability in PFC and basal ganglia