Introduction to Memory and Cognition

Memory and Cognition complaints are some of the most common symptoms in psychiatric and neurologic practice.

  • Retrograde amnesia: inability to remember things that occured prior to a central nervous system injury
  • Anterograde amnesia: Inability to remember things that occur after a central nervous system injury (i.e. - cannot form new memories)

The DSM-5 breaks down cognition into 6 domains:

  1. Social
  2. Language
  3. Executive
  4. Complex attention
  5. Perceptual motor
  6. Learning and memory

On history and mental status:

  • Difficulty remembering recent events (conversations, meals)
  • Increased reliance on lists/calendars
  • Repetition
  • Requires frequent reminders
  • Autobiographical and implicit memory relatively preserved until severe stages

On cognitive testing:

  • Difficulty with repeating words and/or digits
  • Difficulty with delayed recall
  • Rey Auditory Verbal Learning Test

On history and mental status:

  • Expressive
    • Word-finding difficulty
    • Decreased spontaneity of speech
    • May not recall names of friends or family
    • Paraphasic errors, substitution of specific terms with general
      • “that thing” or “you know what I mean”
  • Comprehension

On cognitive testing:

  • Expressive - Naming, verbal fluency (letter and category), “Boston Naming”
  • Comprehension – verbal commands

On history and mental status:

  • Increased reliance on others or maps for directions
  • Getting lost
  • Difficulties with previously familiar tasks (carpentry, sewing, driving)
  • Gnosis – inability to recognize familiar objects

On cognitive testing:

  • Drawing a clock
  • Figure copying - cube/intersecting pentagons
  • Demonstrating learned movements, i.e. - testing for apraxia (wave goodbye, show me how you would comb your hair)

On history and mental status:

  • Change in personality
  • ↓ Empathy
  • ↓ Recognition of emotions
  • Apathy
  • Inappropriate social behavior

On cognitive testing:

  • Identification of emotions in images of faces
  • Theory of Mind story cards – elicit information about characters

On history and mental status:

  • Difficulty with multitasking
  • Decision making
  • Problems with IADLs

On cognitive testing:

  • Trail making test
  • Clock drawing (+visual-spatial tasks)
  • Working memory: repeating letters/numbers backwards
  • Insults to circuits from dorsolateral prefrontal cortex (frontal) going all the way basal ganglia/thalamus (deep brain structures) can be be responsible for bedside “frontal” findings

On history and mental status:

  • Routine tasks take longer or more errors
  • ↑ Difficulty in environments with multiple stimuli (TV, radio, conversation)
  • ↑ Difficulty holding new information in mind (e.g. - phone numbers, addresses)

On cognitive testing:

  • Digit span forward
  • Vigilance A test (tapping)
  • Spelling backwards

Memory Systems

Adapted from Budson, A. E. et al (2007). Memory dysfunction in neurological practice. Practical neurology, 7(1), 42-47.
Memory System Example Awareness Length of storage Anatomy
Episodic memory Remembering a short story, what you had for dinner last night, and what you did on your last birthday Explicit Minutes to years Medial temporal lobes, anterior thalamic nucleus, mamillary body, fornix, prefrontal cortex
Semantic memory Knowing who was the first President of the US, the colour of a lion, and how a fork and comb are different Explicit Minutes to years Inferior lateral temporal lobes
Procedural memory Driving a standard transmission car (explicit), and learning the sequence of numbers on a touch-tone phone without trying (implicit) Explicit/Implicit Minutes to years Basal ganglia, cerebellum, supplementary motor area
Working memory Phonological: keeping a phone number ‘‘in your head’’ before dialing
Spatial: mentally following a route, or rotating an object in your mind
Explicit Seconds to minutes; information actively rehearsed or manipulated Phonological: prefrontal cortex, Broca’s area, Wernike’s area
Spatial: prefrontal cortex, visual association areas