A. Graphic representation of the AAL ROIs identified in the
multivariable analysis (flipped brain). B. and C. plots show the top 40 (of
about 1700) correlated psychological/task terms using Neurosynth reverse
inference decoder for the brain regions (B) and weighted regions, given the
model estimate coefficients (C). The size of a term in each word cloud is
proportional to the correlation strength of term/region. Blue color represents
top 5 correlations. D-E: A multiple regression model using the logistic
regression/LASSO results for flipped brain KOA classification predicted
neuropathic pain score (DN4) in a subsample of KOA patients (training sample,
n=45). This result was validated on a KOA holdout sample (test sample, n=46),
but not in the HOA group. C. shows the relative importance of all predictive
variables where % of R2 is normalized to sum 100%. Bars correspond to
1000 bootstrap confidence intervals at 95%. E. shows the validation of the
obtained regression model in KOA testing sample and HOA groups. Predicted
neuropathic pain scale (DN4) strongly and significantly correlated with the
actual score in the KOA test group, but not in the HOA. DN4 (Douleur
Neuropathique en 4 questions); **p<0.001.