Memory & Alzheimer’s Disease

HOW ALZHEIMER”S DISEAESE AFFECTS VARIOUS MEMORY SYSTEMS

• Remembering Events (Episodic Memory)

Deficits in this system are among the earliest signs of Alzheimer’s disease. Within episodic memory, there are memories classed as short term (having happened in the last hour) and those classed as long term (having occurred more than an hour ago).  Begins with misplacing keys, forgetting to paying bills thus family members consider as senior moments. However more serious and dangerous examples of forgetting include not remembering to turn off the stove and to take medications. Deficits in episodic memory represent the most significant functional problems as the patient advances from the mild to moderate stages of the disease.

Most people remember distant past easier than recent events. This is because memories decline in reverse order to when they were formed. Events related to persons with Alzheimer’s disease remain in their memories longer than things they just experienced. A person may remember what they wore to a school dance 50 years ago but cannot remember what they just ate breakfast

The temporal lobe, which contains the hippocampus, and the frontal lobe are important to episodic memory, which enables us to learn new information and remember recent events. The hippocampus is one of the first brain structures damaged in Alzheimer’s disease. As the hippocampus becomes more and more dysfunctional during the course of the disorder so does the ability to register events and send them to storage.  This accounts for one hallmark of early Alzheimer’s: difficulty remembering recent events, without any trouble remembering events from long ago.  Thus patients with Alzheimer disease may benefit from watching movies to discussing events in their lives. All memories may not be beneficial and could cause psychotic delusions and hallucinations. Examples are when the patient reports having seen or interacted with a deceased relative or friend.

• Taking in new information

As the disease progresses it becomes more and more frustrating for the patient and the caregiver that the person can no longer remember recent events or learn new information  When something in short-term memory is forgotten, it means that a nerve impulse has merely ceased being transmitted through a particular neural network.  The hippocampus again plays an important role in getting short term memories into long term memories. Thus the progressive damage to the hippocampus in Alzheimer’s disease prevents the formation of new memories. Thus processing of new information is not functioning so persons will not recollect having heard the information. The information is just not being retained so they will believe it is the first time they have heard it. Therefore it becomes difficult to teach your relative not to repeat themselves because they are not registering the information.

To assist a person use pictures, calendars, gestures. Introduce routines and keep things on a schedule. Avoid saying that you have already said something.

• Semantic Memory

This system also involves the temporal lobes and, multiple areas within the cortex. People with Alzheimer’s disease may be unable to name a common object or to list objects in a category, such as farm animals or types of birds. Alzheimer’s disease patients tend to display a loss of knowledge of the specific characteristics of semantic categories. Initially, they lose the ability to distinguish fine categories, such as species of animals or types of objects, but, over time, this lack of discrimination extends to broader, more general categories. Thus, at first, an AD patient may see a spaniel and say, “that is a dog”; later, they may just say, “that is an animal”

• No longer Recognizing people and places

Eventually persons with Alzheimer ‘s disease will no longer be able to recognize persons or places. In fact sometimes the person may think a relative is an intruder or that a relative is their spouse or even parent. No longer being recognized by a beloved family member can become distressing. It helps to have discussions with family and friends which can assist to better cope with this situation.

• Separating fact from fiction

It is common as the disease progresses that the person will start to confuse facts and what they imagined. This is known as delusions. This occurs in the middle stages of the disorder. This can cause conflict between the person and the caregiver as well as family members. It is quite common that the person may loose an object and then start accusing a person of stealing it this can be money or any personal item.   Keep in mind that while this is not in your reality it is the way in which the person with Alzheimer disease copes with his/her world as cognitive faculties declines. While these accusations may be hurtful keep in mind that this is not person speaking but rather a consequence of the disease.

Also it is quite common that the person may seem to be making up stories.  This is because the truth may be mixed up with up residual and patchy memories. Correcting small details may cause the person with Alzheimer’s disease to withdraw and no longer want to participate in family activities.

• Procedural Memory

The cerebellum is one of the structures involved in procedural memory. This memory system typically is not damaged in Alzheimer’s disease or is one of the last cognitive domains to deteriorate.