Quantitative assessment of corpus callosum morphology in periventricular nodular heterotopia

email: heath.pardoe@nyulangone.org

www: https://sites.google.com/site/hpardoe

Corpus callosum area measurements, brain volume measurements and demographic data are contained in the file cc.aseg.wmhypo.ant.post.demo.anon.csv. This is a comma delimited text file that can be opened using programs like Excel, gnumeric etc.

Statistical analyses are contained in the file source.me.cc.wmhypo.R. This file can be read using R. Open the file in a text editor if you're interested in seeing how I modelled the data.

How to recreate statistical analyses using R:

Download both files provided below, change into the directory containing these files and run the following commands in R:

> source("source.me.cc.wmhypo.R")

Typing the R commands listed in the table will provide summary statistics

eg. typing "cc.area.lm" should give the following output:

Call:

lm(formula = CC_area ~ diagnosis + EstimatedTotalIntraCranialVol +

gender + age, data = cc.aseg.demo)

Residuals:

Min 1Q Median 3Q Max

-256.03 -62.52 -8.25 57.90 362.04

Coefficients:

Estimate Std. Error t value Pr(>|t|)

(Intercept) 2.863e+02 7.648e+01 3.743 0.000264 ***

diagnosispvnh -1.073e+02 1.768e+01 -6.067 1.14e-08 ***

EstimatedTotalIntraCranialVol 2.167e-04 4.982e-05 4.350 2.59e-05 ***

genderM 1.068e+00 1.842e+01 0.058 0.953861

age 9.436e-01 7.286e-01 1.295 0.197405

---

Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1

Residual standard error: 97.85 on 141 degrees of freedom

Multiple R-squared: 0.3613, Adjusted R-squared: 0.3432

F-statistic: 19.94 on 4 and 141 DF, p-value: 4.961e-13

The row beginning "diagnosispvnh" gives an estimate of the effect size (difference in corpus callosum area between controls and pvnh participants, -1.073e+02) and the p value associated with this effect (1.14e-08)