Memory is one of the most important cognitive domains with respect to everyday function and is the process of storing, encoding, and retrieving information. Different forms of memory are recognised, including delayed/short-term, long-term, and immediate/working memory.
Memory problems can vary in severity and cause different types of signs and symptoms.
Common symptoms associated with memory loss include the following:
- Confabulation (i.e., invented memories or real memories recalled out of sequence)
- Difficulty handling day-to-day affairs, such as keeping appointments, or preparing meals
- Forgetting words, people, facts, and events that were previously known well
- Getting lost while walking or driving in a familiar area
- Misplacing items in inappropriate places e.g. putting a wallet in a kitchen drawer
- Increased difficulty in following directions or taking a step-by-step approach to a familiar task
- Taking longer to complete familiar tasks, such as following a recipe
- Language difficulties, such as mixing up words or trouble remembering a word e.g., saying "bed" instead of "table"
- Neurological disorders (e.g., tremors, uncoordinated movements)
- Asking the same questions repeatedly
- Having changes in mood or behaviour for no apparent reason e.g. depression, anxiety, irritability
Immediate or Working memory is a short-term memory system that allows concurrent retention and manipulation of information. It is used for thinking about what is already known and for deriving conclusions on the basis of that knowledge; therefore, working memory is fundamental to successful completion of many activities. For example, it is used to remember what has been said at the beginning of a sentence and retain this until the sentence has been completed and is essential for the calculation of mental arithmetic.
Delayed or Short-term memory refers to the function that temporarily retains stimuli that have just been perceived. Its capacity is limited in terms of the number of items that can be stored and lasts for 20 seconds. Through repetition, information may be transferred from short-term memory to long-term memory.
Long-term memory refers to information that is represented on a more permanent basis. Unlike short-term memory, long-term memory has no known limits to capacity and is relatively durable.