Clinical Approaches to Memory Disorders

Human memory is so important to daily life that any theory that could explain
its structures and processes and thus potentially improve its functioning
would be invaluable. Memory is inextricably tied to learning, planning,
reasoning, and problem solving; it lies at the core of human intelligence.
None of the three theories is by itself sufficient to explain all the phenomena
associated with memory. Over the years, a number of ideas have been
developed in the attempt to improve memory functioning through passive
means. Efforts to induce learning during sleep and to assess memory of patients
for events taking place while under anesthesia have had mixed results,
but on the whole have not succeeded. Memory enhancement through hypnosis
has been attempted but has not been shown to be very effective or reliable.
Pills to improve memory and thereby intelligence have been marketed but so far have not been shown to be the answer to memory problems. Research
has begun on the possibility that certain drugs (such as tacrine) may
interactively inhibit memory loss in people afflicted with certain kinds of dementia
(for example, Alzheimer’s disease). Work in neuropsychology has
shown the influence of emotion-triggered hormonal changes in promoting
the memory of exciting or shocking events (such as one’s first kiss or an
earthquake). This has led to an understanding of state-dependent memory:
Things learned in a particular physical or emotional state are more easily remembered
when the person is in that state again. This helps explain the difficulties
in remembering events that took place when a person was intoxicated
or depressed. In fact, heavy use of alcohol may result in significant
memory loss. A person may not even remember having injured someone in
a car crash. Although not fully researched, it may be that certain kinds of
memory are mood-congruent. Perhaps memories of events that occurred
when a person was in a certain mood may become available to the person
only when that mood is again induced.

More active means for memory improvement have met with greater success.
Associationist theory has demonstrated the value of the use of mnemonics,
devices or procedures intentionally designed to facilitate encoding
and subsequent recall. The use of rhymes, acronyms, pegwords, and the like
enables people to recall factual information such as the number of days in
each month (“Thirty days have September . . . ”), the names of the Great
Lakes (the acronym HOMES), and the colors of the visible spectrum (ROY
G. BIV). Visual cues, such as tying a string around one’s finger or knotting
one’s handkerchief, are traditional and effective ways to improve prospective
memory. Cognitive psychology has demonstrated the importance of
emotional factors—how and why something is learned—to the effectiveness
of memory. It has provided the research base to demonstrate the effectiveness
of study strategies such as the SQ3R (survey, question, read, recite, review)
technique. Cognitive theory has also shown that metamemory, a person’s
knowledge about how his or her memory works, may be important for
the improvement of memory.

In clinical settings, much research has been concerned with memory impairment
as a means to test the applicability of theories of memory. Head injuries
are a common cause of amnesia in which events immediately prior to
an accident cannot be recalled. Damage to the hippocampus, a part of the
brain that is vital to memory, breaks down the transfer of information from
short-termto long-termmemory. One dramatic case concerns “H. M.,” a patient
who had brain surgery to control epileptic seizures. After surgery,
H. M.’s short-term memory was intact, but if he was momentarily distracted
from a task, he could not remember anything about what he had just been
doing. The information was never transferred to long-term memory. Such
patients still remember information that was stored in long-termmemory before
their operation, but to them everyday experiences are always strangely
new. They can read the same paragraph over and over, but each time the material will be brand-new. In H. M.’s case, it was discovered that his intelligence
as measured by standardized tests actually improved, yet he was continually
disoriented and unable to learn even the simplest new associations.

Intelligence tests are made to measure general information, vocabulary,
and grammatical associations; these things were stored in H. M.’s long-term
memory and were apparently not affected by brain surgery. In cases less dramatic
than H. M.’s, damage to particular areas of the brain can still have devastating
effects on the memory. Damage can be caused by accidents, violent
sports activity, strokes, tumors, and alcoholism. Alzheimer’s disease is another
area to which research findings on memory may be applied. In this fatal
disease a patient’s forgetfulness increases from normal forgetting to the
point that the patient cannot remember how to communicate, cannot recognize
loved ones, and cannot care for his or her own safety needs.
Associationism, cognitive psychology, and neuropsychology can each explain
some of the structures and processes involved in these and other realworld
problems, but it seems as though none of the theories is sufficient by
itself. Memory is such a complex phenomenon that it takes all the largescale
theories and a number of smaller-scale ones to comprehend it. The
truth probably is that the theories are not mutually exclusive, but rather are
complementary to one another.