Understanding Memory Disorders

Memory disorders are disorders of cognition, the ability to reason, remember, make decisions and communicate. Our team has in-depth experience treating a wide variety of memory disorders, including dementia, Alzheimer’s disease, mild cognitive impairment, vascular cognitive impairment and hydrocephalus.

Memory disorders can be caused by one or more factors, including:

  • aging
  • trauma
  • substance abuse
  • heredity (inheriting genes associated with Alzheimer’s or Huntington’s disease)
  • narrowing of the arteries that provide blood flow to the brain
  • cardiovascular disease
  • untreated infectious or metabolic disease
  • brain tumors
  • vitamin deficiencies.

Some types of memory disorders can appear suddenly, while others may be present years before symptoms become apparent. A skilled neurologist can help determine whether the progression of a memory disorder can be slowed or even reversed entirely.

Types of Memory Disorders

More than 100 health conditions are associated with cognitive decline, the ability to reason, remember, make decisions and communicate.

Click to expand a topic below and learn more about the different types of memory disorders:

Alzheimer disease is a brain illness that can happen usually in older adults, but it can also happen as early as age 40. It is the most common cause of dementia. It is a progressive disease. This means it gets worse over time. It afflicts an estimated 5.3 million Americans, and it is the seventh leading cause of death.

Alzheimer disease causes a series of changes to nerves of the brain. Some nerves form into clumps and tangles, and lose some of their connections to other nerves. Age is the most important risk factor for Alzheimer’s disease. Other risk factors include heredity, diabetes, hypertension, traumatic brain injury and poor nutrition.

The disease causes changes in behavior and thinking known as dementia. The symptoms include:

  • Memory loss
  • Confusion
  • Restlessness
  • Personality and behavior changes
  • Problems with judgment
  • Problems communicating with others
  • Inability to follow directions
  • Lack of emotion

As Alzheimer’s disease progresses, short-term memory deficits become more severe and interfere more with the maintenance of daily activities. In moderate Alzheimer’s disease, individuals typically require more assistance with daily activities, and as the disease progresses may even require assistance with essential daily activities, such as preparing a meal or requiring reminders to attend to hygiene. n severe Alzheimer’s disease, individuals are almost entirely dependent on others to ensure adequate hygiene and proper nutrition, and they may require prompts or assistance for common functions such as using the toilet.

Learn more about the treatment for Alzheimer’s Disease.

Encephalitis is inflammation and swelling of the brain. This leads to changes in neurological function, resulting in mental confusion and seizures. Viruses are the leading cause of encephalitis. Vaccines for many viruses, including measles, mumps, rubella, and chickenpox have greatly lowered the rate of encephalitis from these diseases. But, other viruses can also cause encephalitis. These include herpes simplex virus and rabies. Encephalitis can also occur after an infection caused by disease-carrying agents including ticks (Lyme disease), mosquitoes (West Nile virus), and cats (toxoplasmosis). Encephalitis can also be caused by bacteria.

In addition to cognitive impairments, a wide variety of other neurologic manifestations may occur. These include:

  • Parkinsonism – slowness of movement, increased rigidity in the arms and/or legs, problems with walking
  • Seizures
  • Weakness or sensory changes affecting one side of the body
  • Problems with speech, swallowing, double vision or other “focal” neurologic symptoms
  • Loss of ability to perform learned motor movements
  • Inattention to visual or sensory stimuli on one side (e.g., ignoring these things on the left side of the body)
  • Tremor
  • Headache

Learn more about the treatment for Autoimmune Encephalopathy.

Dementia is the name for a group of brain conditions that make it harder to remember, reason, and communicate. Dementia is a descriptive term rather than a diagnosis. The most common form of dementia is Alzheimer disease. Other types include vascular dementia, frontotemporal dementia, and Lewy body dementia. Years ago, dementia was often called “senility.” It was even thought to be a normal part of aging. We now know that it’s not normal. It’s caused by ongoing damage to cells in the brain.

Symptoms differ depending on which parts of the brain are affected and the stage of the disease. The most common symptoms include:

  • Memory loss, including trouble with directions and familiar tasks
  • Language problems, such as trouble getting words out or understanding what is said
  • Difficulty with planning, organizing, concentration, and judgment. This includes people not being able to recognize their own symptoms.
  • Changes in behavior and personality

Dementia is a progressive disease. This means it gets worse over time. Symptoms differ for each person, but there are 3 basic stages. Each may last from months to years:

  • In the early stage, a person may seem forgetful, confused, or have changes in behavior. However, he or she may still be able to handle most tasks without help.
  • In the middle stage, more and more help is needed with daily tasks. A person may have trouble recognizing friends and family members, wander, or get lost in familiar places. He or she may also become restless or moody.
  • In the late stage, Alzheimer’s can cause severe problems with memory, judgment, and other skills. Help is needed with nearly every aspect of daily life.

Learn more about the treatment of dementia.

Frontotemporal dementia (FTD), a common cause of dementia, is a group of disorders that occur when nerve cells in the frontal and temporal lobes of the brain are lost. This causes the lobes to shrink. FTD can affect behavior, personality, language, and movement.

These disorders are among the most common dementias that strike at younger ages. Symptoms typically start between the ages of 40 and 65, but FTD can strike young adults and those who are older. FTD affects men and women equally.

The most common types of FTD are:

Frontal variant. This form of FTD affects behavior and personality.

Primary progressive aphasia. Aphasia means difficulty communicating. This form has two subtypes: Progressive nonfluent aphasia, which affects the ability to speak. Semantic dementia, which affects the ability to use and understand language. 

A less common form of FTD affects movement, causing symptoms similar to Parkinson disease or amyotrophic lateral sclerosis (Lou Gehrig’s disease).

The cause of FTD is unknown. Researchers have linked certain subtypes of FTD to mutations on several genes. Some people with FTD have tiny structures, called Pick bodies, in their brain cells. Pick bodies contain an abnormal amount or type of protein.

Damage to the frontal lobe of the brain may impact important functions. Common symptoms involve dramatic changes in behavior and personality. These may include:

  • An increased tendency to make socially inappropriate comments or actions
  • Decreased empathy, or new difficulties understanding how one’s actions may impact others
  • Difficulties with logical judgments or understanding the relationship between cause and effect
  • Changes in sexual behaviors
  • Aggressive behaviors or actions
  • Decline in personal hygiene, toileting habits, etc.
  • Severe mental rigidity
  • Language abnormalities, such as being unable to express language, find words or understand the meaning of words
  • Inattention, increased distractibility or a tendency to jump from one topic to another
  • Difficulty initiating or completing tasks
  • Significant changes in eating patterns

In addition to cognitive impairments, neurologic symptoms may occur including:

  • Parkinsonism: slowness of movement (bradykinesia), increased rigidity in the arms and/or legs, problems with walking (short stride length or a “shuffling” gait)
  • Tremor
  • Muscle spasms and/or rippling of the muscles underneath the skin
  • Seizures

Learn more about the treatment for Frontotemporal Dementia.

Dementia with Lewy bodies (DLB) is a form of progressive dementia caused by degeneration of the tissues in the brain. DLB may be genetic, but it is not always clear why someone develops it.

People with DLB have a buildup of abnormal protein particles in their brain tissue, called Lewy bodies. Lewy bodies are also found in the brain tissue of people with Parkinson disease (PD) and Alzheimer disease (AD). However, in these conditions, the Lewy bodies are generally found in different parts of the brain.

The presence of Lewy bodies in DLB, PD, and AD suggests a connection among these conditions. But scientists haven’t yet figured out what the connection is.

DLB affects a person’s ability to think, reason, and process information. It can also affect movement, personality and memory. DLB becomes more prevalent with age. It often starts when a person is in his or her 60s and 70s.  DLB is progressive, which means it continues to develop over time. There are several types of dementia with different causes.

The main sign of DLB is a progressive decline in things like memory, thinking, and problem solving. This decline is enough to affect the ability to work and do normal daily activities. Although memory may be affected, it isn’t usually as impaired as in someone with Alzheimer disease.

DLB is generally diagnosed when at least 2 of the following features are also present with dementia:

  • Changes in attention and alertness. These changes may last for hours or days. Signs of these changes include staring into space, lethargy, drowsiness, and disorganized speech.
  • Visual hallucinations. These hallucinations recur and are very detailed. They generally don’t bother the person having them.
  • Movement symptoms consistent with Parkinson disease (PD), such as slow movement, shuffling gait, rigidity, and falls. The person may also have tremors, but not as pronounced as in a person with PD with dementia.

Other signs and symptoms seen in DLB include:

  • Depression
  • Sleep disorder that affects REM sleep, causing vivid dreams with body movement
  • Dizziness, feeling lightheaded, fainting, or falling
  • Urinary incontinence

In DLB, memory problems often occur later in the disease. DLB can be confused with other forms of dementia, but it also has unique features, such as hallucinations and delirium.

Learn more about the treatment for Dementia with Lewy Bodies.

Mild cognitive impairment (MCI) is an intermediate state between normal thinking and memory (cognition) and dementia. Patients with mild cognitive impairment can have difficulty with memory, language, thinking and judgment that are greater than would be expected for their age. People with MCI may be at an increased risk for developing Alzheimer’s Disease.

Patients with a family history of Alzheimer’s and dementia are at greater risk for developing MCI. Other risk factors include age, high cholesterol, high blood pressure, diabetes and hypothyroidism.

Learn more about the treatment for mild cognitive impairment.

Vascular cognitive impairment is the second most common form of dementia after Alzheimer disease. It’s caused when decreased blood flow damages brain tissue. Blood flow to brain tissue may be reduced by a partial blockage or completely blocked by a blood clot.

Symptoms of vascular dementia may develop gradually, or may become apparent after a stroke or major surgery, such as heart bypass surgery or abdominal surgery.

Dementia and other related diseases and conditions are hard to tell apart because they share similar signs and symptoms. Although vascular dementia is caused by problems with blood flow to the brain, this blood flow problem can develop differently. Examples of vascular dementia include:

  • Mixed dementia. This type occurs when symptoms of both vascular dementia and Alzheimer’s exist.
  • Multi-infarct dementia. This occurs after repeated small, often “silent,” blockages affect blood flow to a certain part of the brain. The changes that occur after each blockage may not be apparent, but over time, the combined effect starts to cause symptoms of impairment. Multi-infarct dementia is also called vascular cognitive impairment.

The effect of decreased or no blood flow on the brain depends on the size and location of the area affected. If a very small area in a part of the brain that controls memory is affected, for example, you may be “forgetful” but it doesn’t necessarily change your ability to carry on normal activities. If a larger area is affected, you may have trouble thinking clearly or solving problems, or greater memory problems that do change your ability to function normally.

Vascular dementia is caused by a lack of blood flow to a part of the brain. Blood flow may be decreased or interrupted by:

  • Blood clots
  • Bleeding because of a ruptured blood vessel (such as from a stroke)
  • Damage to a blood vessel from atherosclerosis, infection, high blood pressure, or other causes, such as an autoimmune disorder

Symptoms of vascular cognitive impairment (VCI) differ from the early symptoms of Alzheimer’s disease. Given the varied definitions of VCI, it is not surprising that clinical symptoms vary significantly in individual patients.

The symptoms of vascular dementia depend on the location and amount of brain tissue involved. Vascular dementia symptoms may appear suddenly after a stroke, or gradually over time. Symptoms may get worse after another stroke, a heart attack, or major surgery. These are signs and symptoms of vascular dementia

  • Increased trouble carrying out normal daily activities because of problems with concentration, communication, or inability to carry out instructions
  • Memory problems, although short-term memory may not be affected
  • Confusion, which may increase at night (known as “sundown syndrome”)
  • Stroke symptoms, such as sudden weakness and trouble with speech
  • Personality changes
  • Mood changes, such as depression or irritability
  • Stride changes when walking too fast, shuffling steps
  • Problems with movement and/or balance
  • Urinary problems, such as urgency or incontinence
  • Tremors

Learn more about the treatment for Vascular Cognitive Impairment.

Explore the UC Memory Disorders Center