[Construct validity of some episodic memory tests for psychogeriatric patients]

Episodic memory is the conscious recollection of personal experiences. In clinical practice several episodic memory tests are used, but their validity as measures of an episodic memory construct is not clear. The sensitivity and specificity of variables hypothesized to represent a distinct psychological construct is established by a pattern of convergent and discriminant validity. Confirmatory factor analysis was used to analyse the correlations between four episodic memory tests: a standardized orientation questionnaire, free recall, and two delayed recognition memory tests. The episodic memory construct was contrasted with an executive functioning construct, measured by three variables: two tasks of semantic word fluency and the Expanded Mental Control Test. The measures were taken from 813 consecutive visitors of a psychogeriatric day care centre. As a set the four indicators of episodic memory provided reliable measurement of the construct. The same was true for the three measures of the executive functioning construct. However, the strong correlation (0.89) between the two constructs implies a lack of discriminant validity and suggests that processes of executive control contribute to the successful performance on episodic memory tasks.