Are children with developmental dyslexia all the same? A cluster analysis with more than 300 cases

Abstract

Reading is vital to every aspect of modern life, exacerbated by reliance of the internet, email, and social media on the written medium. Developmental dyslexia (DD) characterizes a disorder in which the core deficit involves reading. Traditionally, DD is thought to be associated with a phonological impairment. However, recent evidence has begun to suggest that the reading impairment in some individuals is provoked by a visual processing deficit. In this paper, we present WISC‐IV data from more than 300 Italian children with a diagnosis of DD to investigate the manifestation of phonological and visual subtypes. Our results indicate the existence of two clusters of children with DD. In one cluster, the deficit was more pronounced in the phonological component, while both clusters were impaired in visual processing. These data indicate that DD may be an umbrella term that encompasses different profiles. From a theoretical perspective, our results demonstrate that dyslexia cannot be explained in terms of an isolated phonological deficit alone; visual impairment plays a crucial role. Moreover, general rather than specific accounts of DD are discussed.

A Cross-sectional Study on Awareness of Dyslexia Disorder among University Students

“…Hence, the null hypothesis is rejected and the alternative hypothesis is accepted which stated that the prevalence of dyslexia awareness among university students is <0.5 within a confidence level of 95%. It is clear that the majority of undergraduate students not well aware of dyslexia disorder [2]. The association testing between the course of study and awareness of dyslexia is tested using Fisher's exact test which is an alternative of Pearson's Chi-square test.…”

“…According to The National Organization for Dyslexia Malaysia, dyslexia is defined as a learning disability leading to difficulty in acquiring the basic skills of reading, spelling, and writing [1]. Dyslexia is a language-based disability, but it is often misunderstood as a disease or an intellectual defect [2]. It is the neurological origin and it is characterized by difficulties with accurate and/or fluent word recognition and poor spelling and decoding abilities and does not affect the intelligence of the person [3].…”

Rapid Automatized Naming and Explicit Phonological Processing in Children With Developmental Dyslexia: A Study With Portuguese-Speaking Children in Brazil

“…Cognitive performance measures reveal that individuals with dyslexia can present deficits in a broad range of tasks including impairments in phonological, visuospatial, attentional, working memory, and executive function measures (Menghini et al, 2010;Zoubrinetzky et al, 2014;Tamboer et al, 2016). Although different subtypes of dyslexia are discussed in the literature (Giofrè et al, 2019), there is a general consensus that children with dyslexia present weaknesses in phonological processing skills (Snowling, 2001;Ramus et al, 2003;Vellutino et al, 2004;Ziegler and Goswami, 2005). According to the most widely accepted view in the field (see Hulme and Snowling, 2009, for a review), decoding deficits seen in dyslexia arise from poorly specified phonological representations (the phonological representations hypothesis).…”

Double Trouble: Visual and Phonological Impairments in English Dyslexic Readers

“…Furthermore, it would be interesting to evaluate processing skills in the phonological and visual domains of dyslexic readers within different cultures, particularly those reading different orthographies (e.g., transparent languages such as Italian, see Provazza et al, 2019 for some considerations about dyslexia in different languages). Finally, large-scale studies should be performed to understand whether dyslexia operates as an umbrella term encompassing several different problems, such as phonological and visual processing (Giofre et al, 2019).…”