Differences in phase synchrony of brain regions between regular and dyslexic readers

Dyslexia is a learning disability that impairs a person´s ability to decode words accurately and fluently. This deficit can manifest itself as difficulties in orthographic working memory, brain systems asynchrony, poor executive function skills and/or rapid naming processing. Although each of the aforementioned factors incorporates different brain systems and is activated at different speeds and in different manners, it is clear that for good reading performance to occur, these systems must be activated in a synchronized manner (hence, the name “A-synchronization Theory”). This aforementioned theory of A-synchronization indicates that impairment among dyslexic readers involves not only the speed of processing but also the integrating and processing of information emerging from different sensory systems, specifically, the visual and auditory modalities. Based on this, an effective algorithm was developed for analysis and classification of subjects as either Regular Readers or Dyslexic Readers. This was achieved by measuring phase synchrony in Electroencephalographic (EEG) recorded channels during visual Lexical Decision task. An average correct identification rate of 89% ± 2% was achieved when phase synchrony features from the gamma-band (30-40Hz) were extracted. This may indicate a lack of synchrony between different modalities in dyslexic readers related to attention process.