That's not what I see in that plot. I see a distribution shift, with zero linkage between before and after cases that would suggest "Half had more gray matter"

That's not what I see in that plot. I see a distribution shift, with zero linkage between before and after cases that would suggest "Half had more gray matter" Figure 2 is the one you want https://els-jbs-prod-cdn.jbs.elsevierhealth.com/cms/attachment/e84bb276-f386-405b-bfc5-37d1cbcf1fef/gr2.jpg https://els-jbs-prod-cdn.jbs.elsevierhealth.com/cms/attachme... Which does show effect increasing with severity of the case. I've seen plots like that before in similar articles. See also table 2.