Neural correlates of phonological, orthographic and semantic reading processing in dyslexia

Abstract

Developmental dyslexia is one of the most prevalent learning disabilities, thought to be associated with dysfunction in the neural systems underlying typical reading acquisition. Neuroimaging research has shown that readers with dyslexia exhibit regional hypoactivation in left hemisphere reading nodes, relative to control counterparts. This evidence, however, comes from studies that have focused only on isolated aspects of reading. The present study aims to characterize left hemisphere regional hypoactivation in readers with dyslexia for the main processes involved in successful reading: phonological, orthographic and semantic. Forty-one participants performed a demanding reading task during MRI scanning. Results showed that readers with dyslexia exhibited hypoactivation associated with phonological processing in parietal regions; with orthographic processing in parietal regions, Broca's area, ventral occipitotemporal cortex and thalamus; and with semantic processing in angular gyrus and hippocampus. Stronger functional connectivity was observed for readers with dyslexia than for control readers 1) between the thalamus and the inferior parietal cortex/ventral occipitotemporal cortex during pseudoword reading; and, 2) between the hippocampus and the pars opercularis during word reading. These findings constitute the strongest evidence to date for the interplay between regional hypoactivation and functional connectivity in the main processes supporting reading in dyslexia.

From Schools to Scans: A Neuroeducational Approach to Comorbid Math and Reading Disabilities

“…• Left superior frontal gyrus (105) • Left middle frontal gyrus (105) • Left inferior frontal gyrus (106)(107)(108) • Left superior temporal gyrus (107,(109)(110)(111) • Left superior temporal sulcus (107,(109)(110)(111)(112) • Left middle temporal gyrus (113) • Left inferior temporal gyrus (108,109,114) • Left fusiform gyrus (112,(114)(115)(116) • Left superior parietal cortex (117) • Left inferior parietal cortex (117) • Left angular gyrus (105,109,110,118,119) • Left supramarginal gyrus (120,121) • Left middle occipital gyrus (112) Hyperactivation during phonological tasks:…”

Profile and neuropsychological differences in adolescent students with and without dyslexia

“…The neurocognitive impairment is also multifactorial and involves phonological processing deficits, with weaknesses in oral language skills and processing speed (Peterson & Pennington, 2015;Ramus, 2003). According to Paz-Alonso et al (2018), dyslexia is usually manifested by difficulties with phonological segmentation, slow linguistic processing, poor vocabulary, low verbal fluency and reduced operative memory, short-term verbal memory or speech perception and other symptoms generally associated with dyslexia, although they do not necessarily cause problems. Thus, Power, Colling, Mead, Barnes & Goswami (2016) suggest that alteration in the neural coding of low frequency voice envelopes, related to speech prosody, can support the phonological deficit that causes dyslexia in all languages.…”

“…Scientists tend to argue that a problem in the development of certain brain regions could be the cause of the progressive establishment of this specific difficulty in learning to read manifested by dyslexics. Neuroimaging studies have found quantitative differences in the brain areas involved in reading skills, as well as cognitive and behavioural skills (Paz-Alonso et al, 2018;Yitzchak & Pavlakis, 2001). Paulesu et al (2001) conducted comparative studies of 72 adults with dyslexia problems in France, the United Kingdom and Italy.…”

Children’s neurodevelopment of reading is affected by China’s language input system in the information era

“…Learning to read involves the ability to recognize, understand, and use forms of written language, which is highly correlated with orthographic, phonological, and semantic skills. These linguistic skills provide a foundation for one's reading ability [3][4][5] . While knowledge acquisition and electronic modes of communication have led to increased reliance on typewriting over handwriting in the digital age, it is critical to evaluate the effect of digital technology on reading development [6][7][8][9][10][11] .…”