gms | German Medical Science

Determination of the cerebral language representation is an essential step in the presurgical diagnostic work-up of epilepsy patients. Invasive procedures as the intracarotid amytal-test are increasingly replaced by non-invasive functional magnetic resonance imaging (fMRI). However, fMRI requires cooperation of the patients and reports on the application of this method in paediatric patients are scarce. We retrospectively reviewed the language fMRI studies of the last 4 years in order to evaluate the usefulness of clinical language fMRI studies in children and adolescents.

In the period from 12/1999 until 12/2004 in our department 247 clinical language fMRI studies were performed. In 52 studies the patients were younger than 18 years (13x 6 to 10 y., 25x 11 to 15 y., 14x 16 or 17 y.). Most patients were candidates for epilepsy surgery. FMRI was performed on a 1.5T scanner with multislice gradient echo EPI sequences. Different language paradigms requiring semantic decisions and/or covert language production were used. Stimuli were presented visually or acoustically. Data evaluation included motion correction, spatial and temporal smoothing, and a correlation analysis. "Activated" voxels (r>0.5) were colour-coded and superimposed onto anatomical T1-weighted images.

In the youngest age group (<10 y.) 6/13 studies (46%) were non-diagnostic, in the majority of cases due to movement artefacts. In two patients a diagnostic result could be obtained in a second fMRI after several months. In the older children (11 to 15 y.) 6/25 (24%), and in the adolescents (16 to 18 y.) 2/13 (15%) of the fMRI studies were non-diagnostic. The best results concerning lateralisation were obtained with visually presented paradigms in all age groups.

Even in 6 to 10 years old children a successful determination of the cerebral language representation by fMRI was possible in the majority of our cases, although, as expected, in younger children the number of drop outs due to movement artefacts was higher than in older children and adolescents. Thus, in the diagnosis of the cerebral language representation fMRI should be the procedure of first choice in all age groups.