Aging and Memory

General Considerations

  • See also the broader discussion of Aging and Cognition
  • Many aspects of memory deteriorate w/ age
  • Decline affects recent memory more than immediate or remote
  • Ability to encode, store, and recall info is typically reduced in older adults; that is, memory processes become less effective, although the content of memory (knowledge) can continue to increase
  • Four different levels of memory functioning can be identified during life span
    • Peak performance reached at some point during adulthood; may be maintained by rare individuals who are said to enjoy superior aging
    • Age-appropriate decline; scores remain w/in range that is average for age
      • terms used here include age-associated memory impairment, benign senescent forgetfulness, and age-associated cognitive decline
    • Mild Cognitive Impairment: significantly below age-adjusted norm on standardized test, but without ADL impairment
    • Dementia: deterioration reaches level where interferes w/ ADLs

Normal Aging

  • Vast majority of neurons grow to be as old as owner
    • thus, each neuron exposed to cumulative effect of bio wear and tear throughout life
  • Aging depends on interaction of 3 variables:
    • time
    • genetic background
    • stochastic encounters w/ diverse events such as stress, hypertension, oxidation, trauma, etc.
  • Age-related changes are not necessarily intrinsic to aging – ie, aging may not cause the events but may increase the probability of encountering them; differentiating inevitable consequences of aging and cumulative (BUT preventable) impact of stochastic events embedded w/in time is very complex
  • Normal aging characterized by increased interindividual variability
  • Biological Components
    • Healthy aging ass’d w/ small loss of brain volume, but rate doesn’t accelerate w/ advancing age
    • Traditional view that aging is ass’d w/ massive loss of neurons is wrong
    • Cortical myelination seen to increase into 7th decade!
    • Aging brain retains considerable potential for structural plasticity
  • In sum, on AVERAGE
    • advancing age increases risk for losing neurons, synapses, transmitters, and cognitive acuity
    • but, many “age-related” changes might reflect preventable stochastic events
    • nonetheless, greatly enhanced vulnerability for dementing diseases

Mild Cognitive Impairment


  • Refers to transitional state between normal cognitive aging and mild dementia
  • It includes subjective memory complaint, corroborated by objective memory impairment on standardized test, but adequate general cognitive ability and ADLs ok
  • Since other forms of MCI exist, MCI emphasizing memory loss is termed Amnesic MCI


  • Individuals who present w/ MCI will not necessarily have same outcome since have different causes (could be DLB, FTD, etc.)


  • Individuals w/ MCI evolve to dementia at rate of 10-15% per year (normal is 1-2% per year)
    • variables that predict more rapid decline include apolipoprotein E4, atrophic hippocampi on MRI


  • No effective treatment currently known, but cholinesterase inhibitors, anti-inflammatory agents, and anti-oxidants (eg, vitamin E) all theoretically make sense