08: Neurocognitive Disorders

Question 1

What are the core features of a neurocognitive disorder?

Answer 1

• Primary clinical deficit is in cognitive function (different from intellectual disability)
• Core features are cognitive
• Deficit is acquired, not developmental
• Decline from previously attained level of functioning

Question 2

What are the cognitive components of the Mental Status Exam?

Answer 2

• Attention & orientation
• Memory
• Complex functions and language
• Abstract thought

Question 3

Describe how attention & orientation are assessed.

Answer 3

• Attention: able to direct, focus, sustain and shift attention
• Awareness: orientation to the environment; three spheres (OX3 = “oriented times three”):
  
  • Person
  • Place
  • Time (usually first to decline)

NB: If all intact, AOx3.

Question 4

Describe how memory is assessed.

Answer 4

• Immediate: 3 objects (e.g., purple, rock, cat)
• Short-term: 3 objects after 2-5 minutes
• Intermediate: Breakfast, recent current events (mayor of NYC)
• Long-term/fund of knowledge: Personal history, presidents

Question 5

Describe how to assess complex functions and language.

Answer 5

• Serial 7s or 3s
• WORLD backwards
• Money calculations
• Word-finding and naming (e.g., point at watch, “what is this?”)

Question 6

Describe how to assess abstract thought.

Answer 6

• Comparison: “What qualities do an apple and orange share? A chair and a desk?”
• Proverbs: “Can you explain to me what it means when I say ‘blood is thicker than water?’”

NB: Concrete means there is not capacity for abstract thought (e.g., “apples and oranges are round”); abstract thought can also be observed during the interview.

Question 7

Describe the differences between delirium and neurocognitive disorders.

Answer 7

• Delirium: brainstem (i.e., more primitive functions of attention)
• Major/minor neurocognitive disorder: cerebral cortex (i.e., higher level “executive” functions)

Question 8

What are the characteristics of delirium?

Answer 8

• Disturbance in attention and awareness
• Additional disturbance in cognition or presence of perceptual disturbance (e.g., visual hallucination)
• Develops over short time period, represents change from baseline, fluctuates in severity over course of day
  
  • Sundowning: worst at night
• Evidence that disturbance is the direct physiological consequence of another medical condition, substance intoxication/withdrawal, or exposure to toxin

Question 9

What is the epidemiology and course of delirium?

Answer 9

• Children & elderly at highest risk (least stable brains)
• 10-30% of hospitalized patients
• Life-threatening emergency until proven otherwise
• Course depends on etiology

Question 10

What are the characteristics of a major neurocognitive disorder?

Answer 10

• Significant cognitive decline in one or more cognitive domains:
  
  • Attention
  • Social cognition (empathy, recognition of social cues)
  • Perceptual & motor (navigation, coordination)
  • Executive function (planning, decision-making)
  • Learning & memory
  • Language (naming and comprehending)
• Cognitive deficits interfere with independence in everyday activities
• Not exclusively in the context of delirium

Mnemonic: Neurocognitive disorders are like being under A SPELL.

Question 11

Describe the characteristics of a minor neurocognitive disorder.

Answer 11

• Modest cognitive decline in one or more cognitive domains
• Cognitive deficits do not interfere with independence in everyday activities, although greater effort or compensatory strategies may be required

Question 12

What is the prevalence of neurocognitive disorders?

Answer 12

• Major NCD/dementia: 1-2% of the general population at > 65yrs; 30% at >85yrs.
• Minor NCD/mild cognitive impairment: 2-10% of general population at >65yrs; 5-25% at >85yrs.

Question 13

What is the etiology of major/minor NCD?

Answer 13

Due to:

• Dementia (most commonly Alzheimer’s disease, Parkinson’s disease, cardiovascular disease)
• Traumatic brain injury
• Infection (e.g., HIV)
• Other medical cond. (e.g., brain tumor, endocrine disorder)

Question 14

What is the course of NCDs?

Answer 14

Depends on etiology:

• Neurodegenerative diseases: Insidious onset and gradual decline
• Cardiovascular disease: Step-wise or stuttering decline
• Traumatic brain injury: Acute change

Question 15

What are suggestive signs/symptoms of a mental disorder due to another medical condition?

Answer 15

• Age > 40 yrs. if new onset
• Inconsistent w/ usual presentation
• Abnormal neurological exam