Description

A diffusion tensor imaging dataset used in Swihart et al. (2012). Mean diffusivity profiles for the corpus callosum (cca) and parallel diffusivity for the right corticospinal tract (rcst). Accompanying the profiles are the subject ID numbers, visit number, and Paced Auditory Serial Addition Test (pasat) score. We thank Dr. Daniel Reich for making this dataset available.

Format

A data frame made up of

cca

a 340 x 93 matrix of fractional anisotropy profiles from the corpus callosum;

rcst

a 340 x 55 matrix of fractional anisotropy profiles from the right corticospinal tract;

id

numeric vector of subject ID numbers;

visit

numeric vector of the subject-specific visit numbers;

pasat

numeric vector containing the PASAT score at each visit.

Details

If you use this data as an example in written work, please include the following acknowledgment: “The MRI/DTI data were collected at Johns Hopkins University and the Kennedy-Krieger Institute"

Note: DTI2 uses mean diffusivity of the the corpus callosum rather than fractional anisotropy (FA), and parallel diffusivity of the rcst rather than FA. Please see the documentation for DTI for more about the DTI dataset.

References

Goldsmith, J., Bobb, J., Crainiceanu, C., Caffo, B., and Reich, D. (2011). Penalized functional regression. Journal of Computational and Graphical Statistics, 20(4), 830–851.

Goldsmith, J., Crainiceanu, C., Caffo, B., and Reich, D. (2012). Longitudinal penalized functional regression for cognitive outcomes on neuronal tract measurements. Journal of the Royal Statistical Society: Series C, 61(3), 453–469.

Swihart, B. J., Goldsmith, J., and Crainiceanu, C. M. (2014). Restricted Likelihood Ratio Tests for Functional Effects in the Functional Linear Model. Technometrics, 56, 483–493.