dyslexia

Question 1

what is dyslexia?

Answer 1

Dyslexia is a reading disability of neurological origin that persists throughout life despite adequate intelligence, education, and socioeconomic background (Snowling et al, 2000).

Question 2

several decades of research

Answer 2

Several decades of research have shown that dyslexia strongly impinges on cognitive functioning, even beyond reading. For example, associated problems have been reported in sensory functioning (Stein, 2001), working memory (Smith-Spark & Fisk, 2007), and motor learning (Howard et al, 2006).

Question 3

theories

Answer 3

In terms of the theories attempting to explain these cognitive impairments, there have been a number of conflicting accounts (Ramus et al., 2003). Some have focused on key aspects of impaired language processing, such as phonological awareness (e.g., Vellutino et al 2004), or on associated visual–sensory problems (e.g., the magnocellular deficit theory; Stein, 2001) and perceptual problems (e.g., the perceptual anchor theory; Ahissar, 2007), or even on motor learning dysfunctions (e.g., the automaticity/cerebellar deficit theory; Nicolson & Fawcett, 1990).

Question 4

SOLID

Answer 4

However, more recently Szmalec et al (2011) proposed an alternative theory, suggesting that dyslexia could reflect an impairment in serial order learning, or the ability to recall information in the order/ sequence presented. This process is known to play a crucial role in cognition, language learning and processing and is also thought to lead to increasingly robust lexical representations, allowing a familiar letter string to be automatically retrieved during reading (Majerous and Cowen, 2016). Therefore, this theory suggests that individuals with dyslexia are less sensitive to such repetitions, and consequently less likely to learn (and automatize) sequences. There is evidence both for and against this theory.

Question 5

For (number 1)

Answer 5

In support of the SOLID hypothesis, Szmalec et al (2011) ran a 3 part experiment looking at the hebb learning ability (a task relying on on serial order learning) of people with and without dyslexia and across different modalities (Verbal-visual, Verbal-auditory and Auditorily-visuospatial). They observed that individuals with dyslexia, when compared to typical adults, showed smaller improvements in recall of the Hebb sequences across all modalities, relative to the filler trials. However, performance on the nonrepeating filler trials was comparable for dyslexic and typical groups. As a result this study suggested that it was sequential learning that was impaired in dyslexia and not STM, as has been previously suggested. Furthermore, 87% of the typical adults and 81% of the dyslexic participants reported awareness of the Hebb repetitions, suggesting that sequence learning was impaired in dyslexia despite participants having a certain degree of explicit knowledge of their sequential learning processes.