Serial position effects scoring in the assessment of memory in Alzheimer's disease and major depression

Abstract

The objective of this thesis was to validate serial position effects (SPE__S) scoring in the Rey Auditory Verbal Learning Test (RAVLT). The RAVLT is a much used clinical method for assessing memory performance, but the method of scoring obfuscates that two memory processes underlie free recall. This is suggested by SPE__S of single-trial free recall , although the extent of the effects are not defined. The internal and external validity of SPE__S of the RAVLT is studied. The internal validity of SPE__S is studied by means of confirmatory factor analysis. It is shown that the recency effect comprises two to three items, while the primacy effect and middle (prerecency) comprise the remaining items in a list, implying that they arise from two memory functions. Studies testing their external validity show that they play a variant role in memory impairment of Alzheimer__s disease and Major Depression patients and are found to be differentially related to stress hormone activity in these patients, and in healty human subjects. Scoring of accurately determined SPE__S in the RAVLT is a valid improvement of clinical memory assessment. As serial position effects are further found in the recall of a variety of types of information, and also found in the animal, it is argued that they are general to temporal information processing.