Analysis of the control condition of a language fMRI task: a simple alternative to assess visuospatial functions?

Problem: In order to increase the rate of successful functional MR studies in children it is helpful to shorten scanning time [1]. To assess two cognitive functions with one task seems to be a promising approach. The hypothesis of this study was that performing the control condition of an established language task (vowel identification task, VIT [2]) requires visuospatial functions and that the VIT therefore may also be applicable to localize these functions.

Methods: 43 children (19 f, 12,0±2,6 years) were recruited. 42 of the children performed the VIT, consisting of five blocks of the active condition („Is there an „i“ in the name of a [visually presented] object?“) and six blocks of the control condition („Does this [unnameable abstract] pattern fit in another pattern like a piece of a puzzle?“). Additionally, all of the children performed the visual search task (VST [3]), an established task to localize visuospatial functions, which requires the comparison of two complex figures. Data was acquired on an 1.5 T MR scanner; datasets were unwarped and motion corrected, spatially normalized [4], smoothed (FWHM=9mm), and statistically analysed using SPM8. Following random effects analyses (p<0.01, FWE corrected), activation patterns in the VIT (control>active) were compared to those of the VST.

Results: Substantial overlap of activation of the VIT (control>active) and the VST was observed in bilateral, but right-dominant, superior parietal areas.

Conclusions: The overlapping activations in regions associated with visuospatial functions [5] indicate that visuospatial functions are required by both tasks. Therefore, we suggest that the VIT, apart from only being applicable to assess language, is also applicable to assess visuospatial functions.

Literatur:

[1] Yerys, Jankowski et al., Hum Brain Mapp, 2009

[2] Wilke, Lidzba et al., Neuroimage, 2006

[3] Lidzba, Staudt et al., Neuroreport, 2006

[4] Wilke, Holland et al., Neuroimage, 2008

[5] Ng, Bullmore et al., J Cogn Neurosci, 2001