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Working Memory and Inhibition in Down Syndrome: Is There a Specific or General Deficit?

Sun, April 19, 10:35am to 12:05pm, Sheraton, Floor: Second Level, Missouri

Abstract

The cognitive profile of individuals with Down syndrome (DS) is known to be characterized by an impaired working memory (e.g. Lanfranchi et al., 2010). Within working memory, and in particular concerning central executive (see for example Baddeley, 2000) inhibition play a central role. It has recently been suggested that cognitive inhibition should be seen not as a unitary process, but as a family of functions. Friedman and Miyake (2004) recently proposed an empirically supported taxonomy distinguishing between three inhibition-related functions. The first function proposed was named ‘‘prepotent response inhibition’’, which enables dominant and prepotent motor or cognitive responses automatically activated by the stimulus presented to be blocked; the second was ‘‘response to distracter inhibition’’, which enables attention to be focused on relevant items by ignoring simultaneously presented irrelevant items; and the third was termed ‘‘resistance to proactive interference’’ and refers to the ability to dampen the activation of no longer relevant items and thus resist memory intrusions (intrusion errors). The aim of the present study was to investigate whether individuals with DS have any specific or general deficit in inhibitory processes.
Tasks measuring prepotent response inhibition (the animal Stroop test), proactive interference (proactive interference task and intrusion errors), and response to distracters (directed forgetting task) were administered together with a working memory test to 19 individuals with DS and 19 typically developing (TD) children matched for mental age. Confirming previous findings, our results showed that the DS group performed less well in a verbal working memory task than the TD children. Analyzing our findings for the three inhibitory tasks yielded a picture of the DS children having a generalized difficulty in suppressing information that is irrelevant, or no longer relevant, to the goals of the task. These results suggest that DS is related not to specific, but rather to generalized inhibitory difficulties. Implications for reading and oral comprehension will be discussed.

References
Baddeley, A.D. (2000). The episodic buffer: a new component of working memory? Trends in Cognitive Sciences, 4, 417–423.

Lanfranchi, S., Jerman, O., Dal Pont, E., Alberti, A., Vianello, R. (2010). Executive function in adolescents with Down Syndrome. Journal of Intellectual Disability Research, 54(4), 308-319.

Friedman, N.P., & Miyake, A. (2004). The relations among inhibition and interference cognitive functions: A latent variable analysis. Journal of Experimental Psychology: General, 133, 101–135.

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