Wpływ wieku nabycia języka obcego na wzorce pobudzenia ośrodków mowy

Bibliogr. s. 27-28

Background: The of aim of the present study was to evaluate the influence of the acquisition age of the second language on activation patterns of language areas. Material/Methods: Forty volunteers participated in the study (20 females and 20 males). Their age ranged from 18 to 40 years. A mean age was 28 years. All participants had possessed a high proficiency of the acquired foreign language. They were divided into two groups, according to the age of the foreign language acquisition. The participants who acquired the second language before puberty, were qualified to the early acquisition group. The remaining participants were qualified to the late acquisition group. The second criterion was the level of the acquired, foreign language. Proficiency in using the language was assessed by a teacher. Block design method was used in the performed experiment. The experimental task was speech production in the form of voiceless sentences, the control task was silence. Each experimental session consisted of five 30-second alternating blocks. Every volunteer participated in two sessions, where she/he described his house without the use of voice. One session applied the native language, L1, and the other one the foreign language, L2. The experiment was performed using MR Signa Horizon system (GE Medical Systems, USA) with 1.5 T magnetic field strength. Functional images were obtained using the echoplanar sequence (EPI) that applies spin echo and is sensitive to the changes of the BOLD (Blood Oxygenation Level Dependent signal) signal having the following parameters: TR =3000 ms, TE =60 ms, flip angle 90°, FOV =28x21 cm, matrix 96x96 pixels, 1 NEX. Functional data analysis was performed using SPM2 software (Wellcome Department of Cognitive Neurology, Great Britain). Results: In EA and LA groups, the cortex activation was not more intense in patients speaking their native language, as compared to the foreign language. In the LA group, left inferior frontal gyrus (pars triangularis) showed more activation in L2. In the EA group, the activation in L2 was found in inferior frontal gyrus (pars triangularis) and in a small part of the left middle frontal gyrus. Conclusions: The Age of acquisition of the foreign language influences the pattern of activation of language areas, mainly in regions involved in syntax. Early age of acquisition allows one to acquire the rules of syntax in L2 in a similar manner as in L1. © Pol J Radiol, 2009.