Neural Responses of the Anterior Ventral Occipitotemporal Cortex in Developmental Dyslexia: Beyond the Visual Word Form Area

Music literacy improves reading skills via bilateral orthographic development

Considerable evidence suggests that musical education induces structural and functional neuroplasticity in the brain. This study aimed to explore the potential impact of such changes on word-reading proficiency. We investigated whether musical training promotes the development of uncharted orthographic regions in the right hemisphere leading to better reading abilities. A total of 60 healthy, right-handed culturally matched professional musicians and controls took part in this research. They were categorised as normo-typical readers based on their reading speed (syl/sec) and subdivided into two groups of relatively good and poor readers. High density EEG/ERPs were recorded while participants engaged in a note or letter detection task. Musicians were more fluent in word, non-word and text reading tests, and faster in detecting both notes and words. They also exhibited greater N170 and P300 responses, and target-non target differences for words than controls. Similarly, good readers showed larger N170 and P300 responses than poor readers. Increased reading skills were associated to a bilateral activation of the occipito/temporal cortex, during music and word reading. Source reconstruction also showed a reduced activation of the left fusiform gyrus, and of areas devoted to attentional/ocular shifting in poor vs. good readers, and in controls vs. musicians. Data suggest that music literacy acquired early in time can shape reading circuits by promoting the specialization of a right-sided reading area, whose activity was here associated with enhanced reading proficiency. In conclusion, music literacy induces measurable neuroplastic changes in the left and right OT cortex responsible for improved word reading ability.

How phonological and orthographic decoding complicates the simple view of reading in Chinese: examining mediation through listening comprehension

Advocates of the science of reading have invoked the simple view of reading (SVR) to justify an approach that foregrounds decoding in early reading instruction. SVR describes reading comprehension as the product of decoding and listening comprehension. The current study examined the complexity of the SVR, focusing on the phonological and orthographic decoding in third-grade readers of Chinese. One hundred and forty-three students participated in this study. The measures included phonological decoding (pinyin invented spelling), orthographic decoding, listening comprehension and reading comprehension. Drawing upon regression analyses and multivariate path models, the study found that phonological decoding at both segmental and suprasegmental processing significantly predicted Chinese reading comprehension, yet a more significant effect of orthographic decoding surfaced. And the best-fitting model suggested listening comprehension was better characterized as a mediator rather than a covariance with decoding component in the decoding-reading relation when orthographic decoding was incorporated into decoding component to evaluate the validity of the SVR in Chinese. The results imply that orthographic decoding is a legitimate decoding component and that the two decoding constructs alone are insufficient for higher-level reading ability (reading comprehension) since the contribution appears to be mediated through the path route of oral language capacity (indexed by listening comprehension). This enriches the current understanding of the SVR in non-alphabetic languages and indicates that decoding training on both phonological and orthographic dimension should be highlighted in early Chinese reading instruction.

Is Developmental Dyslexia Due to a Visual and Not a Phonological Impairment?

It is a widely held belief that developmental dyslexia (DD) is a phonological disorder in which readers have difficulty associating graphemes with their corresponding phonemes. In contrast, the magnocellular theory of dyslexia assumes that DD is a visual disorder caused by dysfunctional magnocellular neural pathways. The review explores arguments for and against these theories. Recent results have shown that DD is caused by (1) a reduced ability to simultaneously recognize sequences of letters that make up words, (2) longer fixation times required to simultaneously recognize strings of letters, and (3) amplitudes of saccades that do not match the number of simultaneously recognized letters. It was shown that pseudowords that could not be recognized simultaneously were recognized almost without errors when the fixation time was extended. However, there is an individual maximum number of letters that each reader with DD can recognize simultaneously. Findings on the neurobiological basis of temporal summation have shown that a necessary prolongation of fixation times is due to impaired processing mechanisms of the visual system, presumably involving magnocells and parvocells. An area in the mid-fusiform gyrus also appears to play a significant role in the ability to simultaneously recognize words and pseudowords. The results also contradict the assumption that DD is due to a lack of eye movement control. The present research does not support the assumption that DD is caused by a phonological disorder but shows that DD is due to a visual processing dysfunction.