Alzheimer's disease is a form of dementia caused by the degeneration of healthy brain tissue until the person loses all memory and mental abilities. It is most prevalent in individuals older than 85, but it can strike people of any age. The actual cause is unknown and there has been no cure found, though through Alzheimer's therapy methods such as medication and brain exercises, a person can slow down the progression and reduce the correlation between Alzheimer's and memory loss. The first indicator that Alzheimer's might be present is the loss of memory, specifically short-term memory. A man with Alzheimer's might recall what he wore to a party 15 years ago but cannot remember what he had for breakfast that day, where he lives or why he entered a room.
A person's memory is more than the ability to recall events in the recent or distant past; in fact, a large portion of a person's personality is based on his or her memory. Memory controls a variety of mental functions. Explicit memory is the ability of a person to remember seemingly unrelated words or ideas and recall them later.
For example, if a person is told three random words and is asked to repeat them immediately but cannot, this can be a sign of impaired immediate recall. If immediate recall is impaired, explicit memory will be impaired as well, because the brain cannot store the phrases to be recalled later. This event presents itself as a symptom of Alzheimer's in the example of a person who cannot recall something he or she was told five minutes earlier, such as a sports score, even though the person is an avid sports fan.
Another connection between Alzheimer's and memory is emotion. A person's emotions are directly linked to his or her memory, and all memories evoke some sort of emotion. A memory of a person's wedding day can evoke the emotion of happiness, the memory of losing a loved one will evoke sadness, and remembering a fight with another person can conjure up anger. Emotional reactions to new situations will take their cue from reactions in the past — in other words, how a person reacted previously is a good indicator of how he or she will react in the present. Emotions are fueled by what is remembered, so if the memory is failing, there will be a decrease in overall emotion or an unpredictable or out-of-character reaction.
Other symptoms that suggest a possible onset of Alzheimer's and memory loss include the inability to find the right word, disorientation, a loss of abstract thought abilities and a loss of judgment. Having one or two of these symptoms does not necessarily indicate the presence of Alzheimer's and memory loss. If the majority of the symptoms present themselves, though, there could be an issue.