Aging and Memory

From Brain.aacnwiki.org

Jump to: navigation, search

Contents

GENERAL INFO

  • 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 (MCI)

Definition

  • 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

Heterogeneity

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

Progression

  • 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

Treatment

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


Links Back

Return to the Written Exam Study Notes TOC
Return to the Main Table of Contents
Return to the Written Exam Overview
Personal tools