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Perioperative Neurocognitive Disorders

What are Perioperative Neurocognitive Disorders?

Anesthesia or surgery can affect an individual’s cognition, or, thinking and memory. Perioperative Neurocognitive Disorders (PNDs) are changes to a person’s behaviour or cognition that can occur either before or after surgery.

Types of Perioperative Neurocognitive Disorders

  • Postoperative Delirium: a state of confusion in the first 7 days after surgery.
    • Definition: A disturbance of consciousness, perception, memory, and orientation, which fluctuates throughout the day.
    • Symptoms:
      • Trouble with thinking and attention
      • Agitation or sleepiness
    • Diagnosis:
      • The Confusion Assessment Method is used to diagnose delirium.
  • Delayed Neurocognitive Recovery: a decline in cognition lasting up to 30 days after surgery.
    • Definition: A decline in cognitive function without delirium.
    • Symptoms:
      • Memory impairments
      • Reduced psychomotor skills
  • Postoperative Neurocognitive Disorder: a decline in memory and thinking lasting up to 12 months after surgery.
    • Definition: Any new cognitive impairment that exceeds the expected recovery period and/or lasts up to 12 months after surgery. There is typically no effect on consciousness, orientation, or attention.
    • Symptoms:
      • Memory impairments
      • Difficulty with combining tasks
      • Reduced psychomotor skills

      Mild vs Major:
      • In mild cases, daily function is maintained
      • In major cases, daily function is not maintained
  • Neurocognitive Disorder: is a decline in cognition occurring more than 12 months after surgery.
    • Definition: Any cognitive impairment that persists after one year. This includes both dementia (major) and cognitive impairment (mild).
    • Symptoms:
      • Long-term loss of brain function (mild cognitive impairment)
      • Severe, short-term loss of brain function (delirium, agitation and confusion)
    • Diagnosis: Periodic, regular cognitive assessment using validated neurocognitive tests that demonstrate decrease in function beyond that expected.

      Please contact your family doctor if you have concerns about your cognition.