Cognitive profile of adolescents with math disabilities: Are the profiles different from those with reading disabilities?

Abstract

Adolescents (ages 14–17) with math disabilities (MD, n = 12), reading disabilities (RD, n = 19), math + reading disabilities (MD+RD, n = 12), and average achievers (n = 15) were compared on measures of visual-spatial processing, random generation (inhibition), writing speed, short-term memory (STM), and working memory (WM). Adolescents with MD performed significantly lower than adolescents with RD on measures of visual-spatial processing and visual WM. Adolescents with MD outperformed adolescents with RD +MD on measures of random generation and motor speed. Performance of all three low-achieving groups was inferior to average achievers on measures of random generation, motor speed, and verbal WM. The results were interpreted within a multicomponent model that attributed deficits related to MD in adolescents to deficits related the visual-spatial sketchpad of WM.

Keywords:

• Visual-spatial
• Working memory
• Math disabilities
• Reading disabilities
• Visual-motor

Notes

The author is indebted to the Redlands School District and to Ron Sewell, who as a former doctoral student, played a major role in data entry and collection.

¹The distinction between WM and STM must be clarified. Working memory is defined as a processing resource of limited capacity, involved in the preservation of information while simultaneously processing the same or other information (e.g., Baddeley & Logie, 1999; Engle, Tuholski, Laughlin, & Conway, 1999). Tasks that measure WM assess an individual's ability to maintain task-relevant information in an active state and to regulate controlled processing. For example, individuals performing WM tasks must remember some task elements and ignore, or inhibit, other elements as they complete task-relevant operations. In addition, WM tasks are those that require some inference, transformation and/or monitoring of relevant and irrelevant information (Baddeley & Logie, 1999; Engle et al., 1999). In our studies, WM tasks typically engage adolescents in at least two activities after initial encoding: (a) A response to a question or questions about the material or related material to be retrieved and (b) a response to recall item information that increases in set size. The first part of the task is a distractor of initial encoding items whereas the second part tests storage.

In contrast, tasks that measure STM typically involve situations that do not vary their initial encoding. That is, adolescents are not instructed to infer, to transform, or to vary processing requirements. In those cases, adolescents are simply asked to recall a sequence of items in the order in which they were presented. Clearly both WM and STM tasks involve sharing some common activities on the adolescent's part. For example, both STM and WM tasks invoke controlled processes such as rehearsal (e.g., see Engle et al., 1999, for a review). However, controlled processing on WM tasks emerges in the context of high demands on attention (e.g., maintaining a memory trace in the face of interference) and the drawing of resources from the executive system. Instructions in controlled processing emphasize maintaining information in the face of interference. Interference reflects competing memory traces that draw away from the targeted memory trace. In contrast, controlled processing on STM tasks attempts to maintain memory traces above some critical threshold (Cowan, 1995). This maintenance does not directly draw resources from the central executive system.