Disorders of Attention and Arousal

Question 1

What are four results of impaired attention?

Answer 1

1. Reduced concentration
2. Distractibility
3. Inability to deal with more than one idea / task simultaneously
4. Inability to deal with high task demands

Question 2

What are the prerequisites of attention?

Answer 2

• Arousal and alertness

Question 3

What are the methodological issues associated with measuring attention?

Answer 3

• Pure tests of attention do not exist: Assessment requires tasks that load 1+ large scale network domain (left ventrolateral PFC, dorsal frontoparietal, salience network)
• Requires a multifactorial approach: Because attention is not the by-product of a unitary process, it cannot be adequately assessed on the basis of findings from one specific test
• Absolute performance often proves less informative than measures of performance as a function of time, memory load, or spatial location (attentional capacities can appear normal under certain conditions but abnormal under others)

Question 4

What are 6 parameters that should be considered when assessing attention?

Answer 4

1. Spatial and temporal characteristics of stimulus task
2. Memory demands
3. Processing speed requirements
4. Perceptual and cognitive task complexity
5. Level of effort required
6. Task relevance and reward value

Question 5

What are the 6 types of attention?

Answer 5

1. Arousal
2. Focused attention
3. Selective attention
4. Sustained attention
5. Divided attention
6. Alternating attention

Question 6

How are the number of task switches related to the number of tasks?

Answer 6

t(t-1)/2

t = number of tasks

Question 7

How are arousal and attention different?

Answer 7

• Increases in arousal level can restrict attention by reducing the useful field of view (e.g., missing an exit when you are stuck in traffic)

Question 8

Define arousal, vigilance, and selective attention.

Answer 8

• Arousal: The basic aspect of attention that enable a person to extract information from the environment / body / mind or to select a particular response
• Vigilance: The ability to sustain alertness continuously
• Selective attention: The ability to scan the events / stimuli and pick out ones that are relevant

Question 9

What are the 10 questions that are used when assessing attentional capacity?

Answer 9

1. Is the patient fully alert and able to respond to basic questions and perform simple tasks such as mental arithmetic?
2. Is activity level within normal limits or is the patient slowed or agitated?
3. Does the patient seem to exert adequate effort?
4. Are sensory, perceptual, and motor functions intact?
5. Is attentional capacity reduced? Do impairments consistently appear on tasks requiring high focus levels, working memory, or effort?
6. Is reduced capacity general or limited to specific operations or modalities?
7. If reduced general capacity exists, must rule out possibility that this is due to attention being a general covariant of global cognitive efficiency / intelligence.
8. Is attentional performance temporally inconsistent?
9. Is attention problem limited to sensory selection or also to response selection and / or control?
10. Are executive functions broadly impaired?

Question 10

What are the two categories of attentional triggers?

Answer 10

• Endogenous: Attentional triggers consisting of thoughts / memory / cognition intruding into consciousness
• Exogenous: Attentional triggers consisting of sensory stimuli; faster processing

Question 11

What are the 6 brain regions associated with attention?

Answer 11

1. Reticular activating system
2. Superior colliculus (head and eye movements)
3. Thalamus
4. Parietal lobe
5. Frontal lobe
6. Cingulate cortex

Question 12

What is the reticular formation?

Answer 12

• A network of interconnecting neurons in the brainstem
• Contains RAS
• Thalamus receives reticular activation and projects arousal to cortex
• RAS also projects to prefrontal, limbic, and parietal areas

Question 13

What is the difference between domain specific and domain general control?

Answer 13

• Domain specific: Several tasks competing for cognitive resources within the same domain produce distractibility effects
• Domain general: Several tasks competing for cognitive resources within different domains do not produce distractibility effects
• Control of processing priority in selective attention demands domain specific resources. This loads the selective attentional mechanism and creates difficulty switching between channels. Largely under the control of the frontal lobes.

Question 14

What is arousal and what level is optimal for attention? What are the neuroanatomic correlates of arousal?

Answer 14

• The maintenance of an appropriate level of cerebral activity to successfully complete a task in which one is engaged. A general state of responsivity and alertness.
• Coma and mania represent extreme states of arousal. Attentional performance is impaired by extremes (Yerkes Dodson Law)
• RAS controls wakefulness and alerting mechanisms and modulates attention through arousal of the cerebral cortex
• Brain stem lesions result in sleep disturbances, delirium, and disorders of consciousness

Question 15

What is delirium?

Answer 15

• An organically caused decline from a previously obtained baseline level of cognitive function
• Typified by a fluctuating course, attentional deficits, and a generalized severe disorganization of behaviour
• Involves cognitive deficits, changes in arousal, perceptual deficits, altered sleep wake cycle, and psychotic features

Question 16

What are the 4 DSM-V criteria for delirium?

Answer 16

1. Disturbance of consciousness with reduced ability to focus, sustain or shift attention
2. Change in cognition (memory, orientation, language) or development of perceptual disturbance that is not better accounted for by pre-existing dementia
3. Development of disturbances over a short period of time and fluctuating over the course of a day or over time
4. Evidence by history that these changes are associated with the patient’s general medical condition

Question 17

What are 7 common symptoms of delirium?

Answer 17

1. Disturbance of attention: Patients unable to generate and sustain attention and have problems shifting attention; distractible and lose track of conversations
2. Disturbance of memory: May be a dense amnesic period for duration of illness or have fluctuations
3. Disturbance in thinking: unable to formulate complex ideas or logical trains of thought, reduced problem solving and planning, paranoid delusions
4. Disturbance in sleep wake cycle: Insomnia and worsening confusion occur at night, night time loss of orderly progression of sleep stages
5. Disorders of perception: Distortion of shape and position, sounds, body image, illusions, hallucinations
6. Hyperalertness: Restless, excitable, and vigilant with pressured speech, shouting, laughing, and crying. Increased physical activity and vivid hallucinations.
7. Hypoalertness: Quiet, motionless, speech sparse and slow, incoherent

Question 18

Name 5 medical conditions associated with delirium.

Answer 18

1. Encephalitis
2. Alcohol
3. Seizure
4. Carbon monoxide poisoning
5. Hypo/hyperglycemia

Question 19

Define the 5 types of attention and the tests used to assess them.

Answer 19

1. Focused attention: Directing controlled efforts towards a solution; relies on information in memory and task at hand]
   - All attention tests
2. Selective attention: The process where some informational elements are given priority over others. Differentiated from focus as the ability to respond discretely to a specific stimulus.
   - WCST, Stroop, Letter cancellation
3. Sustained attention / vigilance: The ability to persist with a task that may require continuous and repetitive activity over a relatively long period of time. Vulnerable to fatigue, motivation, neurological / psychiatric disturbances
   - WCST, Letter cancellation, Tests of everyday attention
4. Divided attention: The ability to respond to more than one task at a time or to multiple elements or operations within a task. Capacity is fairly limited. The greater the number of demanding informational sources, the greater the marked decline of attentional performance. Quality of performance depends on how automatic the task is.
   - Trails making test, WAIS, Test of everyday attention
5. Alternating attention: Allows for shifts in focus and tasks. The ability to rapidly shift attention.
   - WAIS

Question 20

List 5 brain regions associated with attention and the outcomes associated with damage to these regions.

Answer 20

1. PFC: Deficits in voluntary initiation and sustaining attention, rapid alternation of attentional focus, and shifting attention
2. Dorsolateral PFC: Initial attentional focus
3. Orbitofrontal cortex: Sustaining attentional focus
4. Thalamus: Transmission of sensory information necessary for sustained or alternating attention
5. Limbic system: Saliency of increasing stimuli provides emotional tone that facilitates attention and memory. Involved with stimulus detection and appropriate alternation of attentional focus.

Question 21

What are the 2 factors that affect measures of attention?

Answer 21

• Speed of information processing: Delayed reaction time, slowed verbal response, slowed overall performance on timed tests in absence of motor disability
• Speed of motor responses: Associated with weakness, poor coordination.

Question 22

What is the cause and symptoms of hemispatial neglect?

Answer 22

• Cause: Stroke that has interrupted flow of blood to right parietal lobe that is thought to be critical in attention and selection.
• Symptoms: Failure to acknowledge objects in field contralateral to lesion but no perceptual deficits are experienced. Patients may also deny the illness.

Question 23

What is the spotlight theory of attention?

Answer 23

• Theory that we can move our attention around to focus on various locations within the visual field
• Spotlight is often but not always localized on the fovea – spotlight can move in absence of eye movements

Question 24

What are the 3 separate mental operations involved in attention, according to Posner?

Answer 24

1. Disengaging of attention from the current location (frontal lobes)
2. Moving attention to a new location (superior colliculus)
3. Engaging attention to a new location to facilitate processing in that location (frontal lobes, WM)

Question 25

What is the main problem with the spotlight theory of attention?

Answer 25

Object based attention: Attention that is directed towards a single object rather than a spatial location

• Bumps on end of object: Faster judgements are made when bumps are on the same object, even though they are further distance away from bumps on two different objects
• We can see a shape even when it is intertwined with other similar shapes. Hard to recall shapes that had been present but not attended to during the task.

Question 26

What is Hemineglect?

Answer 26

• The lack of attention to one side of space, usually the left, as a result of parietal damage
• May only attend to right visual field and/or the right side of the body