Investigating acoustic markers to assess dyslexia
Dyslexia is a reading disorder that affects approximately 10 % of the population and is known to persist through adulthood. It is widely accepted that the difficulty in mapping letters to sounds stems from a broader deficit in perceiving and manipulating speech sounds. For example, children with dyslexia often have difficulties repeating words, merging sounds; for example: ‘What word do these sounds make: can-dy?’, or eliminating sounds within a word, for example: ‘Say time without saying m’. The Marie Skłodowska-Curie Actions(opens in new window) funded EPIC Read project, part of a body of research being conducted by EU-supported projects in this field, lets speech-language pathologists know how they can use these markers clinically. “Today, there is a general misunderstanding of the role of the speech-language pathologists in dyslexia. By providing clinicians with another new clinical benchmark, in the form of speech production, we can decrease the cases of misdiagnosis and strengthen the role of speech-language pathologists in the diagnosis process,” explains project coordinator Sandy Abu El Adas, based at Stony Brook University(opens in new window) in New York. The project’s main goal was to understand the underlying deficit in dyslexia and to elucidate where the breakdown in dyslexia is occurring. “We were also interested in examining acoustic markers associated with dyslexia which may give rise to future studies aimed at standardisation of acoustic markers, leading to fruitful developments in the field,” adds Abu El Adas.
Acoustic-based measures to identify language delays
By using acoustic-based measures the project identified such language delays. The team recorded typically developing children in first-grade ages 6–7 at two timepoints: at the beginning of the school year before reading instruction has begun and at the end of the school year. “We did this because we wanted to examine the unique contribution of reading on speech development as well as find markers at an earlier stage: typically, dyslexia is identified at 8-9 if not later,” says Abu El Adas. The team recorded the children producing words and also tested them on a variety of linguistic and non-linguistic measures, including measures that assess not reading ability. For the neural study, EPIC Read used magnetoencephalography(opens in new window) – although this part of the study is still ongoing. “We know that individuals with dyslexia show phase-misalignment when we measure their brains in the low frequency ranges corresponding to syllabic and prosodic information, so we wanted to see how production adds to diagnosis on top of perception,” explains Abu El Adas.
Looking for acoustic markers for dyslexia in other languages
Abu El Adas feels the project will give rise to future studies investigating acoustic markers in other languages, which may have different phonemic and syllabic structures. “This is important because we need to understand dyslexia through a range of languages to reduce the risk of developing frameworks that may not represent the entire population.”