Visuospatial memory in dyslexia: Evidence for strategic deficits

Abstract

Impairments in working memory are suggested to be one of the defining characteristics of dyslexia, and deficits in verbal recall are well documented. However, the situation regarding visuospatial memory is less clear. In a widely used measure, the Corsi blocks task, sequences of visuospatial locations can be recalled forwards, in the order presented (CF), or backwards, in reverse order (CB). Previous research has suggested that, while CF draws on spatial-sequential resources, CB may load executive and distinctly visual processes. While people with dyslexia typically show no deficit on CF, CB is rarely presented. We present three studies which indicate a consistent dyslexic deficit on CB that can be ameliorated by visual strategy instructions. Our data suggest that, without instruction, people with dyslexia are unable to adopt an effective CB strategy and this is consistent with a deficit in executive function. These results have implications for our understanding of visuospatial memory in dyslexia, and also in terms of the administration of the Corsi task to special populations.

Executive functions in adults with developmental dyslexia

“…Given the severity of deficits in the phonological domain (e.g., Vellutino, 1979), most research on working memory in dyslexia has focused on identifying impairments in phonological loop function (e.g., Ackerman & Dykman, 1993;Cohen, Netley & Clarke, 1984;Gould & Glencross, 1990;Helland & Asbjørnsen, 2004;Jorm, 1983;Palmer, 2000;Roodenrys & Stokes, 2001). However, it has also been argued that the central executive is also impaired in dyslexia (e.g., Bacon, Parmentier & Barr, 2013;Jeffries & Everatt, 2004;Palmer, 2000;Smith-Spark et al, 2003;Smith-Spark & Fisk, 2007), although central executive deficits have been claimed to be restricted to tasks drawing on phonological processing (e.g., Brosnan et al, 2002;Jeffries & Everatt, 2003Kibby, Marks, Morgan & Long, 2004;Schuchardt, Maehler & Hasselhorn, 2008).…”

“…Whilst central executive problems may be most strongly expressed on tasks tapping the function of the phonological loop, there is a growing corpus of research indicating that central executive problems can also be found on visuospatial working memory tasks (e.g., Bacon et al, 2013;Menghini, Finzi, Carlesimo & Vicari, 2011;Olson & Datta, 2002;Swanson, 1992;Swanson, 1999;Varvara, Varuzza, Sorrentino, Vicari & Menghini, 2014), particularly when conditions are cognitively taxing or novel (e.g., Smith-Spark et al, 2003, Smith-Spark & Fisk, 2007. Therefore, it was predicted that executive-loaded working memory deficits would be found across both the phonological and visuospatial domains.…”

Working Memory in Portuguese Children With Developmental Dyslexia

“…(Table 4 about here) Discussion WM deficits have been widely studied and identified as one of the major defining characteristics of DD. Whereas the deficits in PL and CE tasks exhibited by children with DD have been reported extensively (Schuchardt et al, 2008;Smith-Spark & Fisk, 2007;Swanson et al, 2009), the findings regarding VSSP have been inconsistent (Bacon et al, 2013;Kibby & Cohen, 2008;Menghini et al, 2011). …”

“…Research on the relationship between DD and VSSP deficits has yielded mixed results. Although most studies have not found VSSP deficits in individuals with DD (Bacon, Parmentier, & Barr, 2013;Jeffries & Everatt, 2004;Kibby & Cohen, 2008;Schuchardt et al, 2008), others have suggested the presence of significant differences, with individuals with DD performing more poorly than TR (Menghini et al, 2011;Smith-Spark & Fisk, 2007). When visuospatial STM tasks involve CE demands, children with DD tend to exhibit more difficulties.…”

“…For instance, Bacon et al (2013) demonstrated that children with DD exhibited no deficits in the forward recall task of the Corsi Block Test but revealed significant impairments in the backward recall task. In addition, studies comparing the VSSP capacities of children with DD and those with other neurodevelopment disorders have found that children with DD performed better than children with comorbid dyslexia/dyscalculia (Landerl, Fussenegger, Moll, & Willburger, 2009) or other learning difficulties (Jeffries & Everatt, 2004) but achieved scores similar to those of children with attention deficit hyperactivity disorder (ADHD) (Willcutt et al, 2005).…”