When patients have memory complaints or when professionals discuss memory loss, it is often assumed that memory is a singular trait. In fact, however, there is increasing evidence for several types of memory. The distinction between different memory systems is important because some systems may be affected by aging or by disease, while other systems may remain intact. At least three types of long-term memory representation (conceived by Endel Tulving at the University of Toronto) are important for understanding the differential effects of normal aging versus diseases : episodic memory, semantic memory, and implicit memory.

Episodic memory involves conscious recollection of specific events in your life that occurred in a particular time and place. What were you doing when you heard that John Kennedy was assassinated? When the space shuttle Challenger exploded after liftoff? Where did you spend Thanksgiving last year? When did you last see your spouse? What did you eat for breakfast today? All of these remembrances require episodic memory, which allows us to remember what, when, and where. Episodic memory contains information ranging from a few minutes ago to many years ago.

Semantic memory contains our vocabulary and general knowledge of the world, information that is available independent of time and context. Who was John Kennedy? What do you usually eat for Thanksgiving? What kinds of clothes should you wear to your nephew’s wedding? What is your spouse’s name? Note the difference between these questions and the episodic memory questions in the previous paragraph. In the memory laboratory, we might ask someone to name some fruits (semantic memory) or to recall the names of some fruits from a list presented earlier (episodic memory). Healthy older adults-compared to young adults do experience greater difficulty with episodic memory, but not with semantic memory. Alternatively, patients suffering from Alzheimer’s disease suffer loss of both types of memory.

Implicit memory is the most basic type of memory, as it simply requires a response in the presence of a previously experienced stimulus. At the piano or computer keyboard, our fingers seem to “know” where the keys are. When a traffic light turns red, our right foot goes automatically to the brake pedal. When we see a familiar printed word, its pronunciation is immediately available. The second time we visit a foreign country, the vocabulary and expressions come to mind with greater facility. Priming, then, is quite different from the other types of memory in that it requires no conscious recollection but does reveal the effects of prior experience (i.e., memory). In contrast to episodic and semantic memory which involve “knowing when” or “knowing what,” implicit memory has been characterized as “knowing how.”

For an implicit memory task in the laboratory, an individual, an individual might be asked to engage in word puzzles, with no mention of a memory test. Try to complete the following fragments to form words - D_ N_S_U_, AV _C_D_, T_ QU_L_, A_ R_ V _R_, G_ N_RA_I _N, and E_ E_HA_T - although it’s fairly difficult, when the whole words have been seen previously the number of fragments completed rises dramatically, providing evidence of memory. This form of memory occurs even when individuals don’t remember having seen the very same words. Even more striking. amnesics-who, by definition, have extremely poor episodic memory-perform at the same level as normals when an implicit test is used. For present purposes, this finding is of great interest because it shows that

(1) It is possible to tap information stored in memory not normally available to consciousness

(2) That separate memory systems can be differentially affected by factors such as aging and disease.

We will see evidence that implicit memory is invulnerable to the effects of normal aging and may be spared in Alzheimer’s disease as well.

Like many Alzheimer patients, as Mr. Jones’s disease progressed, alter ations in nutrition were noticed, there was a significant weight loss. It became important to assess food likes and dislikes, to determine if he was able to feed himself, and to ascertain the nutritional value of the food he was eating. It was also important to determine if loose or missing teeth affected his nutrition. Ms. C. was advised to limit the number of choices that he could make, since his ability to decide was impaired. She was encouraged to give assistance with food selections as appropriate. To further encourage adequate intake of calories, Mr. Jones was allowed sufficient time for meals, and privacy was provided so that he was not embarrassed by unacceptable eating habits. Finger food or foods that could be eaten with a spoon were provided because they were man age able and allowed him to be autonomous in his feeding. When Mr . Jones refused to eat adequately at mealtimes, small, frequent feedings were offered. Food supplements (such as Ensure) were used alternatively to assure proper nutrition for Alzheimer treatment.

Methods Of Improving Nutrition

• Provide assistance with food selection as appropriate.
• Ensure privacy so the person is not embarrassed by unacceptable eating habits that may develop.
• When the patient refuses to eat regular food, consider using food supplements.
• Monitor the amount of fluids consumed.
• Offer frequent, small feedings.
• Limit the number of food choices, since decision-making is impaired.
• Since the patient’s motor functioning has decreased, allow sufficient time for meals.
• Provide finger foods or foods that can be easily managed with a spoon.
• Allow the patient to be as autonomous as possible in feeding.
• Avoid extremely hot foods guard against burns.
• Monitor weight at least once per week at the same time, preferably in the morning.

Implicit memory appears to be the most basic memory system, and recent evidence suggests that it continues to function normally in old age, in amnesics, and perhaps in patients with Alzheimer’s disease. Remember that some stimulus must be presented to the subject in order to elicit a response. Either the accuracy of the response (e.g., a subject completes a word fragment) or the speed of the response (e.g., a previously seen item is named faster) reveals the functioning of implicit memory. An implicit memory task that have used involves measuring how long it takes people to name pictures of common objects, such as line drawings of a dog, trumpet, banana, or a chest of drawers, etc. Naming time is measured in milliseconds from the moment a picture comes up on a computer monitor until an individual speaks into a microphone. Only naming times for names successfully retrieved are used in the analysis. When people are asked to name pictures a second time, their naming times are faster than on the first presentation indicating implicit memory for those pictures. This is true even for pictures that people cannot consciously recollect.

Frederick Schmitt and employed this task with three groups of subjects young and old healthy adults and Alzheimer patients. We asked them to name sixty pictures, half of the pictures were presented a second time a few minutes later. Average naming times (not shown) were fastest in young adults, somewhat slower in healthy older adults, and slowest in Alzheimer patients. In spite of the group differences in overall naming speed, the three groups showed equivalent increases in name retrieval speed on the second occurrence (or repetition) of a picture. This phenomenon is called priming and is assumed to reflect the operation of implicit memory. Thus, neither normal aging nor Alzheimer’s disease seems to disrupt the functioning of implicit memory. However, many researchers are actively investigating a variety of priming tasks, because while most of these tasks reveal preserved functioning in patients with Alzheimer’s disease, some do not.

A related finding has been reported by Laura Monti and John Gabrieli and colleagues at the Rush Alzheimer’s Disease Center in Chicago. These investigators asked patients to read passages many times. Their Alzheimer patients showed normal implicit memory as evidenced by increased reading speed for identical passages on subsequent tests. This priming effect was equivalent for a group of normal elderly and the Alzheimer patients, in spite of the latter group’s very poor performance on episodic (recognition) memory tests for the same passages.

Jason Brandt and his colleagues at Johns Hopkins University have employed another priming memory task. In this task, subjects are initially shown a list of words. Later, subjects see a longer list of words, some of which are related to the original list. Subjects are asked simply to say the first word that comes to mind-thus, it is not presented as a memory task. Both Alzheimer patients and normal elderly (mostly patients’ spouses) revealed memory for the original words, in that their word associates to the new list tended to be the original words, at a greater-than-chance level. This priming memory equivalence held in spite of the Alzheimer patients’ poor episodic recall (about 37 percent of the level of healthy older adults).

Daniel Schacter, at Harvard University, published a very interesting example of intact implicit memory in a patient (MT) diagnosed with Alzheimer’s disease. Schacter took MT (an experienced “duffer” in his own words) out for a couple of rounds of golf. MT’s memory for the location of his last shot-episodic memory was quite poor (only 35 percent correct). Likewise, his episodic memory for playing golf with Schactel’ was severely impaired, as he denied having played at all when asked about it a week after the fact. In contrast, his playing ability, and knowledge of etiquette, rules, strategies, and jargon demonstrated remarkable preservation of his semantic and priming memories. In light of the research discussed above, M.T. ’s priming memory is not surprising. His semantic memory functioning, however, is unusually good compared to the average Alzheimer patient, but is in line with his laboratory measures, which show his vocabulary and information skills to be intact. His semantic memory functioning suggests that he is only in the mild stage at this point. It would not be surprising if his golf skills (i.e., priming memory) remain intact for some time after his naming and vocabulary abilities deteriorate in the course of the disease.

The author’s parents recently were in a restaurant in the small town in north Georgia where they live. As dessert came, two men approached his parent’s table. The elder of the two, always the Southern gentleman and ever gracious, complimented his mother on the way she was dressed, then turned to his father and said, “Now I want you to be sure and come by the office tomorrow and sign those papers. We’ve got to get them to court. ”

Such an interchange could occur anywhere. What is important about this event is that the man in question was an attorney by training but had not practiced law for at least ten years and had no business dealings with the author, father for even longer.

The man was successful, being both diligent and smart in his dealings with the courts and clients. However, as he approached his retirement years he became neglectful of his personal appearance and some of his business dealings. He had struggled with alcohol abuse early in his life and had overcome this problem with the help of his law partners. When these new problems of attention to his personal care, business, and social relationships became evident, those who cared for him actively sought to resolve them. He was fortunate that he had business partners who would protect him from the consequences of neglect of important matters and a family who would intervene when needed. As his problems with memory progressed he gave up the practice of law, turned the care of his various business interests to others, and concentrated his efforts on the tasks of retirement. Because of his children’s knowledge and timely intervention, this was a success story for him and his family. However, without thoughtful care, planning, and a willingness to intervene by concerned family members the outcome could have been disastrous.

J. Ray Hays provides an overview of the legal issues that Alzheimer families need to be aware of to ensure that careful planning can be made well in advance of the need for legal intervention. Families facing the difficulties of dealing with a relative who has Alzheimer’s disease need to be aware of the protection and assistance they can obtain from the courts. Families with specific legal problems should consult an attorney who deals with such issues. Elder law, wills, estates, and trusts are an emerging specialty in the law, and a family who takes the time to find competent assistance will be rewarded.