First presented in 1906 by Dr. Alois Alzheimer, Alzheimer's disease affects the patient's cognitive functions, such as long-term memory. Long-term memory consists of permanent memories that the patient can retrieve in the future without the original information in front of her. Alzheimer's disease is the most common type of dementia, which affects 5.3 million people in the United States, according to the Alzheimer's Association. The effects of Alzheimer's disease on long-term memory start in the mild stage of the disorder.
Forgetting Personal History
In the earliest stages of Alzheimer's disease, the patient starts showing signs of short-term memory loss. For example, during mild cognitive impairment, the precursor to Alzheimer's disease, the patient forgets recent conversations, according to the National Institutes of Health (NIH). As the disease progresses, the patient can start forgetting events that occurred during his life, such as where he went to high school.
Not Retaining New Information
When a person is learning new information, it is held temporarily in short-term memory. To become permanent, the memories must be consolidated by the hippocampus, which is located in the temporal lobe of the brain. When those brain cells are damaged, the patient cannot create new long-term memories. For example, the Alzheimer's Association notes that when the patient reads a passage, she retains little information, and cannot answer questions about what she read when asked about it later.
Not Recognizing Family
By the late stage of Alzheimer's disease, the patient has few memory capabilities left. The most devastating effect on long-term memory is the patient no longer remembering his family members. The Alzheimer's Association notes that in mid-stage Alzheimer's disease, the patient may forget the name of his spouse, but that memory lapse is temporary and he remembers the name later. But in severe Alzheimer's disease, which is the end stage of the disease, he cannot recognize his family, even people who are around him every day.
