Working memory function in Chinese dyslexic children: a near-infrared spectroscopy study.

The deficiency theories of dyslexia are quite contradictory and the cross-cultural studies in recent years mainly focused on whether the dyslexics among cultures shared the same cognitive profile or just based on the language. This study used Near-Infrared Spectroscopy (NIRS) imaging to measure the regional cerebral blood volume (BV) and the changes of cerebral activation in the left prefrontal cortex of 12 Chinese dyslexic children and their 12 age-matched normal controls during the Paced Visual Serial Addition Test (PVSAT). Results showed that the scores of PVSAT of dyslexic children were significantly lower than those of the normal children (t=3.33, P<0.01). The activations of the left prefrontal cortex in the normal group were significantly greater than those of dyslexic children (all P<0.01). Our results indicated that Chinese dyslexia had a general deficiency in working memory and this may be caused by the abnormal metabolic activity of brain blood volume in the left prefrontal cortex and the deficits in brain function might be the basis of neuropathology of Chinese dyslexia. Present study supports the difference on brain activation of dyslexics from different languages may be caused by the same cognitive system related to reading.