Development of a new Delayed Memory Index for the WMS-III

This paper presents the Delayed Memory Index (DMI) as an alternative to the General Memory Index (GMI) of the Weschler Memory Scale-Third Edition (WMS-III). The WMS-III Immediate Memory Index (IMI) and the GMI are not parallel in structure, making a direct comparison between these index scores (i.e., immediate vs. delayed memory variables) difficult. The IMI is composed of the sum of scaled scores of four subtests (Logical Memory I, Verbal Paired Associates I, Faces I, and Family Pictures I) while the GMI is composed of the sum of scaled scores of five subtests (Logical Memory II, Verbal Paired Associates II, Faces II. Family Pictures II and Auditory Recognition Delayed). Inclusion of Auditory Recognition Delayed in the GMI is also problematic as it is highly skewed and limited by extreme ceiling effects (see Tulsky, Chiaravalloti, Palmer, & Chelune, 2003). To remedy these problems, we present a new index score that does not include auditory recognition, the Delayed Memory Index. Normative tables for the new Delayed Memory Index based on the inclusion of the Faces subtest, or alternatively the Visual Reproduction subtest, are presented, and initial estimates of their psychometric properties are described.