29: Memory Impairment: Risk Factors

This program will:

• Provide a basic understanding of how memory works and the different kinds of memory
• Discuss some risk factors for memory loss and how they can interfere with normal memory functioning

• There are no easy answer when its comes to the care of another
• Our hope is to offer you useful information and guidelines for caring for someone with dementia
• These guidelines will need to be adjusted to suit your own individual needs

• Memory involves specialized areas of the brain, such as the hippocampus
• Memory is subjective
• People only store information that they are paying attention to
• Nerve cells (neurons) form connections to establish pathways of information
• Gray matter contains nerve cells that form the processing centers for the brain’s functions
• White matter is formed by myelinated nerve fibers (axons)
• Corpus callosum connects the left and right sides of the brain

• There is a miniscule space between nerve cell connections called a synapse
• When a signal in a nerve cell travels from the dendrite to the cell body and onto the end of an axon, chemicals called neurotransmitters are released
• Neurotransmitters leave the axon and cross the synapse to get picked up by a dendrite of the next neuron
• When enough neurotransmitters are picked up by the receiving nerve cell, it triggers a signal that travels down this new nerve cell to cause the release of new neurotransmitters
• This cascade of nerve cell firing and neurotransmitter release is how nerve cells communicate
• Action potential: signal that travel down the nerve cell
• A complex pattern of action potentials through networks of nerve cells and pathways is how information is stored and transmitted in the brain
• In Alzheimer’s disease, the brain produces less neurotransmitters, and nerve cell networks and pathways are damaged and lost

• Memory is the ability to retain and recall information
• Encoding: registering the information
• Storage: creating a permanent record of the encoded information
• Retrieval: calling back the stored information
• Information is acquired and passed into short-term memory
• Short term memory: recall for a period of several seconds to a minute without rehearsal
• Rehearsal: repeated exposure
• Memory consolidation: process by which recent or short-term memories are transformed into long-term memories
• With continued rehearsal, or repeated firings between a network of nerve cells, the connections between them become stronger

• System for temporarily storing and managing information
• Where information is processed and manipulated so that learning, reasoning, and understanding can occur
• Bridge between encoding, storing, and retrieving information
• Used to bring information in and out of storage to manipulate it
• Short-term memory is a type of working memory
• Working memory has limited capacity
• Memory span: number of items that a person can hold onto and recall
• Many older people lose working memory capacity
• Harder for older people to refocus when they are interrupted or distracted
• Comprehension of speech declines with aging
• The more rapid the speech and more complex the sentences, the more difficult it is for older people to understand what is being

• Four types of memory retrieval
  • Recall:being able to access the information without being provided with any part of the memory
    • Answering fill-in-the-blank questions
  • Recollection: reconstructing a memory using pieces of memories, clues, logical structure, and narrative
    • Answering an essay question
  • Recognition: identifying information as a memory after experiencing it again
    • Answering multiple choice or matching questions
  • Relearning:relearning information that has been previously learned, which often strengthens the memory and makes it easier to remember and retrieve the information in the future
• People tend to reorder, reconstruct and condense information to fit their own perception

Types of Memory

• SENSORY MEMORY
• Information that is received through the sensory organs
• Iconic memory: brief mental picture after seeing something
• Echoic memory: brief mental echo of a sound after it is heard

Types of Memory

• EXPLICIT MEMORY PART-1
• Declarative memory
• Involves conscious, intentional recollection
• Acquired knowledge and facts about the world, people, places, objects, and events
• Episodic memory
• Semantic memory

Types of Memory (continued)

• EXPLICIT MEMORY PART-2
• Episodic memory: memory of past events involving oneself that occurred at a particular time and place
• Older people have loss of some episodic memory for experiences and events
• Episodic memory loss can occur at any age with conditions such as sensory overload, depression, stress, or boredom

Types of Memory (continued)

• EXPLICIT MEMORY PART-3
• SEMANTIC MEMORY: memory of meanings, understandings, and other concept-based knowledge
• Generic, context-free, encyclopedic knowledge that a person acquires over a lifetime about things information about words, what they mean, and how they are used
• Aging is not associated with loss of semantic memories

Types of Memory (continued)

• IMPLICIT MEMORY
• Remembering things without being aware that you are remembering them
• Automatic or an unconscious form of memory
• Previous experiences help in performing a task, so that your performance improves with repetition
• Procedural memory
• Walking, tying shoelaces, dressing
• Lost in the later stages of Alzheimer’s disease
• SPATIAL MEMORY
• Stores information about one’s environment and its spatial orientation
• Declines with aging
• Getting lost, missing steps, bumping into objects become potential hazards
• Caregivers should try to de-emphasize the types of memories that are impaired, and try to exercise the person’s retained types of memories

• Risk factor (predisposing factor): anything that increases the vulnerability for a condition
  • Risk factors for memory impairment
  • Family history
  • Lower education level
  • Older age
  • History of head trauma
  • Illness
  • Medications, including alcohol or illicit drugs
  • Vision or hearing impairment
  • Uncontrolled chronic medical conditions, such as congestive heart or kidney failure
• Familial Alzheimer’s disease (FAD) or Early-Onset Alzheimer’s
  • If one parent has FAD, then the children have a 50/50 chance of developing it
• Majority of Alzheimer’s disease cases are late-onset
• No known cause
• Several genes appear to increase the risk
  • Apolipoprotein E4 (ApoE4)
• ApoE2 appears to decrease the risk of developing the disease
• Learning and intellectual exercises may prevent or delay memory loss and the onset of Alzheimer’s disease

• The brain loses nerve cells beginning in a person’s twenties
• Aging is associated with a slowing of brain and body functioning
• Brain noise increases with age, contributing to less efficient and less accurate information processing and performance among the elderly

• Medical conditions that become more common with aging
  • Heart disease, strokes, high blood pressure, high cholesterol, diabetes, and hormonal imbalances.
  • Controlling these medical conditions is essential to reducing the risk of and memory impairment and Alzheimer’s disease
• Aging can directly and indirectly affect memory through changes to the heart, blood vessels, lungs, kidneys, brain, and sensory systems
  • Inefficient circulation
    • Reduces brain functioning, which can cause forgetfulness and confusion
    • Fatigue decreases motivation and attention span
  • Poor lung function
    • Reduces oxygen to the brain
    • Damaging to brain cells
  • Decreased kidney function
    • Toxins can build up in the body and brain
    • Confusion and forgetfulness may be the first signs of kidney problems
    • Poor bladder control can affect attention

• Decreased ability to maintain homeostasis of all the body systems
  • Decrease in immune response increases infections and delays healing and recovery
  • The longer an illness persists, the greater the negative effect on memory and other mental functions
• Reduced vision and hearing
  • Limits ability to observe and understand the environments and activities occurring around them
  • Hinders learning
• Aging itself does not reduce vocabulary and general knowledge, logical thinking, judgment, decision-making ability and other executive functions

• Cautiousness, short attention span, loneliness and depression, poor motivation, indifference, and low self-esteem can affect memory
• Loss of support systems (family and friends) can decrease confidence and self-esteem

• Most frequently diagnosed mental illness in those over 65
• Results in concentration difficulties and inattention to the environment , which can lead to memory problems
• Causes of depression among the elderly
  • Medications and their side effects
  • Chronic illness
  • Chronic pain
  • Decline in the body’s mood elevating substances
  • Changes in body image, physical and mental abilities, careers
  • Loss of loved ones
  • Social isolation
  • Lack of support systems

• Anxiety and stress decrease concentration and attention span
• Excessive or chronic stress or anxiety impacts the body, mind, and behavior

• Any illness that causes pain, discomfort, or fever can cause concentration and memory issues
• Aging is associated with many chronic illnesses
• History of severe head trauma increases the risk of memory problems and Alzheimer’s disease
• Any condition that compromises the ability of the brain to function properly can cause confusion and memory difficulties

• Drugs are a common cause of confusion and memory problems
• Using combinations of drugs increases the risk of adverse drug reactions
• Many medications can impair mental functioning
• Drug withdrawal can cause dementia-like symptoms

• Precipitating factor: an event or condition that elicits or contributes to the occurrence of a problem or to a critical decline of a condition
• Physical trauma
• Confusion the elderly following hip fractures or surgical procedures is a common occurrence
• Personal or financial loss
• Traumatic events can lead to confusion
• Dehydration and malnourishment

• Fluid retention and fecal impaction
  • Occur more frequently among the elderly, especially those with dementia
  • Should always be considered when confusion occurs
• Hyperthermia
  • Overheating of the body can cause delirium and even permanent brain damage
• Fever
  • Delirium at fevers around105 degrees F
• Infection
  • Elderly can have limited ability to mount a fever response
  • Various mechanisms for causing delirium

• Mild cognitive impairment (MCI): mental deficits that do not significantly interfere with functioning or daily life
• Memory problems, slower thinking, and a reduced ability to learn
• Can worsen to become Alzheimer’s
• MCI appears to be a transitional state between normal memory and Alzheimer’s disease in some people
• Preventing or treating MCI could be one approach to decreasing the risk of developing Alzheimer’s

• Causes
• Heart disease and chronic lung diseases (COPD-Chronic Obstructive Lung Disease)
• Reduce oxygen to the brain
• Kidney and liver diseases
• Toxins damage the brain
• Hormonal imbalances
• Thyroid disease
• Poor nutrition and vitamin deficiency
• Vitamins and minerals are important for a healthy brain
• Medications and substance abuse
• Older people are more sensitive to adverse drug reactions

• Without appropriate treatment, dementia that could have been improved or reversed may become irreversible
• Avoid unnecessarily labeling someone
• Forgetfulness occurs at any age and under many different circumstances

• Memory formation and retrieval involves a complex process of signal transduction through a network of nerve cells and pathways
• Information processing and storage requires attention and concentration
• Main types of memory
  • Sensory
  • Explicit memory
    • Episodic memory and semantic memory
  • Implicit
  • Spatial
• Aging is associated with a decline in most forms of memory, particularly working memory, which is needed for information analysis and speech comprehension
• Semantic and implicit memories remain largely intact
• Risk factors for memory impairment
  • Family history, lower education level, older age, history of head trauma, illness, medications, vision or hearing impairment, uncontrolled chronic medical conditions, and psychological factors
• Precipitating factors
  • Physical trauma, personal or financial loss, dehydration, fluid retention, fecal impaction, fever, and infection
• Mild cognitive impairment and reversible dementias can develop into irreversible dementia
• Cause of reversible dementias
  • Chronic medical conditions, vitamin deficiencies, and medications
• By controlling some of the known risk factors for memory impairment, it may be possible to prevent or limit memory loss

Written by:
Catherine M. Harris, PhD, RNCS.
Mindy J. Kim-Miller, MD, PhD

Edited by:
Sasha Asdourian

www.LightBridgeHealthcare.com

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