Hemispheric dominance for language has been assessed by the Wada test which is an invasive technique with considerable risk of complications. Recently, optical topography system has been used as a non-invasive method which is applicable in detecting the language dominance. Our method can be divided into three steps. Firstly, preprocessing is applied to the data. Secondly, we estimate the degree of the speech area. Finally, we calculate laterality index based on the degree of the speech area. Our results demonstrate that our method is effective for decision of language dominance.
