What is memory loss?

Causes and Symptoms

Memory impairment is a common problem, and often a concern among older individuals. Memory problems are not, however, restricted to older adults. They may occur at any age and may be attributable to numerous conditions and behaviors, including the use of alcohol and other drugs. Memory loss occurs in various degrees and may be associated with other evidence of brain dysfunction and other physical and emotional problems. Memory loss may be partial, limited to events immediately before or after a traumatic event. Memory loss may also be complete. Amnesia is the term used to describe complete memory loss. Memory loss may also be permanent or temporary, or may vacillate, with a person slipping in and out of being able to remember appropriately.

Benign senescent forgetfulness. In this condition, the memory deficit affects mostly recent events, and although a source of frustration, it seldom interferes with the individual’s professional activities or social life. An important feature of benign forgetfulness is that it is selective and affects only trivial, unimportant facts. For example, one may misplace the car keys or forget to return a phone call, respond to a letter, or pay a bill. Cashing a check or telephoning someone with whom one is particularly keen to talk, however, will not be forgotten. The person is aware of the memory deficit, and written notes often are used as reminders. Patients with benign forgetfulness have no other evidence of brain dysfunction and maintain their ability to make valid judgments.

Dementia
. In dementia, the memory impairment is global, does not discriminate between important and trivial facts, and interferes with the person’s ability to pursue professional or social activities. Patients with dementia find it difficult to adapt to changes in the workplace, such as the introduction of computers. They also find it difficult to continue with their hobbies and interests.

The hallmark of dementia is no awareness of the memory deficit, except in the very early stages of the disease. This is an important difference between dementia and benign forgetfulness. Although patients with early dementia may write themselves notes, they usually forget to check these reminders or may misinterpret them. For example, a man with dementia who is invited for dinner at a friend’s house may write a note to that effect and leave it in a prominent place. He may then go to his host’s home several evenings in succession because he has forgotten that he already has fulfilled this social engagement. As the disease progresses, patients are no longer aware of their memory deficit.

In dementia, the memory deficit does not occur in isolation but is accompanied by other evidence of brain dysfunction, which in very early stages can be detected only by specialized neuropsychological tests. As the condition progresses, these deficits become readily apparent. The patient is often disoriented regarding time and may telephone relatives or friends very late at night or not realize the time of day. As the disease progresses, the disorientation affects the patient’s environment: A woman with dementia may wander outside her house and be unable to find her way back, or she may repeatedly ask to be taken back home when she is already there. In later stages, patients may not be able to recognize people whom they should know: A man may think that his son is his father or that his wife is his mother. In fact, it is possible for the patient to not even recognize his or her own reflection in a mirror. This stage is particularly distressing to the caregivers. Patients with dementia may often exhibit impaired judgment. They may go outside the house inappropriately dressed or at inappropriate times, or they may purchase the same item repeatedly or make donations that are disproportional to their funds. Alzheimer’s disease is one of the most common causes of dementia in older people.

Multiple infarct dementia. Multiple infarct dementia is caused by the destruction of brain cells by repeated strokes. Sometimes these strokes are so small that neither the patient nor the relatives are aware of their occurrence. When many strokes occur and significant brain tissue is destroyed, the patient may exhibit symptoms of dementia. Usually, however, most of these strokes are quite obvious because they are associated with weakness or paralysis in a part of the body. One of the characteristic features of multiple infarct dementia is that its onset is sudden and its progression is by steps. Every time a stroke occurs, the patient’s condition deteriorates. This is followed by a period during which little or no deterioration develops until another stroke occurs, at which time the patient’s condition deteriorates further. Very rarely, the stroke affects only the memory center, in which case the patient’s sole problem is amnesia. Multiple infarct dementia and dementia resulting from Alzheimer’s disease should be differentiated from other treatable conditions which also may cause memory impairment, disorientation, and poor judgment. It is important to recognize, however, that both conditions may exist in the same person.

Depression
. Depression may cause memory impairment as a result of problems related to concentration and attention. This condition is quite common and at times is so difficult to differentiate from dementia that the term “pseudo-dementia” is used to describe it. One of the main differences between depression that presents the symptoms of dementia and dementia itself is insight into the memory deficit. Whereas patients with dementia are usually oblivious of their deficit and not distressed (except those in the early stages), those with depression are nearly always aware of their deficit and are quite distressed. Patients with depression tend to be withdrawn and apathetic and to show a marked disturbance of affect. In contrast, those with dementia demonstrate emotional blandness and some degree of emotional lability, or a lack of stableness in expressed emotion. One of the problems characteristic of depressed patients is their difficulty in concentrating. This is typified by poor cooperation and effort in carrying out tasks with a variable degree of achievement, coupled with considerable anxiety. Further, anxiety may disrupt memory, compounding any other problems.

Head trauma. Amnesia is sometimes seen in patients who have sustained a head injury. The extent of the amnesia is usually proportional to the severity of the injury. In most cases, the complete recovery of the patient’s memory occurs, except for the events just preceding and following the injury. With traumatic brain injury, however, amnesia may not be the only symptom. Other memory deficits can be observed and experienced. As such, following any head injury, evaluation is advisable, even if the injury is a closed head injury.

Perspective and Prospects

Memory impairment is a serious condition that can interfere with one’s ability to function independently. Any time that memory loss develops, identification of underlying causes should occur because a treatable cause may be found, preventing further memory loss or perhaps reducing the amount of memory loss. In some cases, proper treatment may even reverse memory loss, such as in some conditions related to alcohol-related memory loss. Research examining memory continues to differentiate among conditions involving memory loss. Efforts to better assess conditions and make distinctions earlier in the process of such conditions remain important. The earlier that problems such as dementia can be identified, for instance, the earlier treatment may be able to occur, potentially increasing quality of life.

Research has also identified ways to slow the progression of some diseases related to memory loss. According to the Alzheimer's Association, there are currently five medications approved by the FDA to temporarily reduce the symptoms of Alzheimer's disease—cholinesterase inhibitors and N-methyl-D-aspartate (NMDA), for example. None of these drugs, however, prevent or cure the disease. As the root causes of memory impairment and brain changes are understood, future research may be able to arrest the progress of amnesia and memory loss and even to treat dementias now considered irreversible, such as Alzheimer’s disease and multiple infarct dementia. Exciting research in the area of inflammation and immunological functioning may prove to be productive.

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