Memory training in normal and demented elderly populations: the E-I-E-I-O model.

An heuristic classification scheme for memory interventions is described as a 2 x 2 matrix. One dimension of the matrix addresses the use of internal versus external mnemonics, and the other dimension addresses the use of explicit (effortful/conscious) versus implicit (automatic/unconscious) learning. Most attempts at memory interventions in normal older populations, such as the use of mental imagery, fall within the explicit-internal cell of the matrix and require expenditure of large amounts of cognitive effort. As a result, memory interventions in normal older populations, even when "successful," usually produce results that are limited in their generalization and are usually not maintained over time. Such interventions are rarely attempted in demented populations. Interventions are described that require less effort and are representative of other cells in the classification matrix. These may be more effective for demented and normal elders. Information acquired through these alternative means may eventually be stored internally and become consciously available, often producing an "O!" or "aha" experience when the individual realizes a shift to internal, consciously available storage has taken place.