IR in reading study will help assess dyslexia

Near-IR spectroscopy has been used to follow brain activity during reading tests by monitoring changes in levels of oxy- and deoxyhaemoglobin, in a process which could be applied to speech therapy and in the assessment of dyslexia. Senior reporter Dima Safi from the University of Montreal described the protocol in Brain and Behavior. Subjects were engaged in overt reading tests while wearing special headgear containing 55 IR sources and 16 detectors around the cerebral areas classically associated with reading.

A special set of 390 written words and 390 written non-words (like huyan or tirasate) was devised and the subjects were asked to read them aloud and as accurately as possible while measurements were taken. The total haemoglobin concentrations were significantly increased in some areas of the brain and other differences were found between reading irregular words and non-words. The changes "could be related to the grapheme-to-phoneme conversion characterizing the phonological pathway of reading," the researchers concluded.

While the application of functional near-IR spectroscopy is not new for monitoring brain activity, its application to overt reading is unusual. It has the advantage that it can be adapted to individual subjects by varying the lists of words and their reveal rate. The technique could be used to assess the success of speech therapy and to monitor dyslexia in children and adults. The team plan to add this reading task to the protocol for the presurgical examination of epileptic patients in their laboratory.