Memory Disorders

Anterograde Amnesia

Everyone has lapses of memory. It is common to forget people’s names, the location of your car keys, or the title of the book you read last week. However, some people have more pronounced failures of memory. People with anterograde amnesia have difficulty following the plot of television shows and movies because they cannot remember the storyline. They find newspaper articles confusing because they cannot remember what was written in the previous paragraph. One common complaint of the spouses and family members of amnesics is that they cannot remember what was told to them 5 minutes ago. In extreme cases, amnesics appear to be mentally “stuck” in a particular point in time, usually shortly before some neurological sickness or brain trauma, unable to acquire any new information.

Most cases of amnesia are due to brain damage suffered from head trauma, stroke, or encephalitis in adulthood. However, there are also cases of developmental amnesia, in which the onset of amnesia is at birth or very early in life. This may be due to prenatal brain damage or birth trauma that causes neuronal death. Individuals with developmental amnesia often do not realize that they have memory problems. Instead, parents of such children are often the first to become suspicious when they notice that their child consistently cannot recollect what they had for breakfast or what they did for their prior birthday.

Various forms of amnesia are often portrayed in pop culture, especially movies. Films such as The Bourne Identity and 50 First Dates tell the stories of people who have forgotten their entire lives. This form of amnesia is different from that which we study in our lab. The type of amnesia we are interested in is more accurately portrayed in the movie Memento, in which the main character has trouble remembering anything that occurs after his brain injury. To learn more about how the brain works in general, another easily accessible resource is the PBS website The Secret Life of the Brain. The full television program can also be rented on video.

Transient Global Amnesia

Transient global amnesia is similar to anterograde amnesia except that it typically occurs for a very short amount of time (6 hours for instance). Individuals experiencing this disorder accurately remember their past but fail to create new memories (and there may also be a small amount of retrograde amnesia). They also tend to repeat phrases with the same cadence (e.g. “This reminds me of when my brother fell off a horse.”) multiple times. Symptoms resolve as mysteriously as they appeared, with no medical intervention, although the patient is left with a hole in their memory for the period during the attack. The cause of transient global amnesia is not known. Luckily,  transient global amnesia is a rare event (30 in 100,000) that typically occurs only once in a lifetime.

Frontotemporal Dementia

What It Is

FTD is a group of related conditions resulting from the gradual degredation of portions of the frontal and anterior temporal lobes. It causes a steady and gradual decline in the ability to live alone and manage one’s life. There are several features that distinguish FTD from Alzheimer’s Disease. First, the age of onset for FTD is earlier than Alzheimer’s Disease, usually in the 50’s, and in some reported cases, in the third decade of life. Second, unlike Alzheimer’s Disease, episodic memory, or memory for the ongoing content’s of one’s life, is not usually affected by FTD until later in the disease course.

Symptoms of FTD

There are three variants of FTD:

Behavioral subtype symptoms: changes in personality (loss of extraversion, loss of empathy, childishness, apathy); failure to comply with social rules of behavior and etiquette; changes in grooming and dress.

Semantic dementia symptoms: language deficits, specifically problems with naming. This is not to be confused with a simple retrieval deficit, rather, patients with semantic dementia permanently lose the meaning, or semantics, of words. Early in the illness, a patient might lose the ability to name unusual animals or things such as penguins or colanders. Instead, they might refer to these items as “birds” and “kitchen things.” Later, they lose the ability to name even common objects such as cars. The inability to remember the names of friends and families is also frequently observed.

Progressive non-fluent aphasia symptoms: difficulty producing language fluently, even though word meaning remains intact; later, Parkinsonian symptoms may develop.

The precise cause of FTD is not known. What is known is that around 40% of people with FTD have a family member with FTD or a related dementia. A few genetic mutations have been linked to FTD and researchers are working on finding more.

Research Participants Needed

True anterograde amnesia (not related to Alzheimer’s Disease) is rare. This is especially true for developmental amnesia. If you believe that you are amnesic and are interested in becoming involved in research, please contact us (iolson[at] We will try to get you involved with studies that we are conducting if you live in the Philadelphia area, or we can put you in contact with researchers in your area. Studies typically involve three or four hours of memory assessment.

FTD is less common than Alzheimer’s Disease. If you have received a clinical diagnosis of FTD and are interested in becoming involved in research, please contact us. We will try to get you involved with studies that we are conducting if you live in the Philadelphia area, or we can put you in contact with researchers in your area. Studies typically involve three or four hours of memory assessment and you are paid for your time.

Ongoing Research Around the World

There are other labs conducting research on memory and amnesia; their websites can be valuable resource for information about the latest developments in the field. Some of these labs are listed below.

East Coast
West Coast
Europe and Australia
Support Groups for Frontotemporal Dementia
Support for Alzheimer’s Disease

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