| Lots of thoughts. First, there's a sort of framing issue with "subjective answers to questions" per the press release. These subjective experiences are the very nature of the thing of interest: feeling desperate, crying for help, loss of energy, and so forth. To dismiss them is, at some level, is akin to a chemist dismissing oxygen gas as an appropriate target of study because it's all subatomic particles at some level. These types of press releases often start with this notion, in my mind, because it's necessary to create some sense that the study in question is revolutionary. I do think they're something of a bootstrapping problem with supervised approaches, which is why in psychopathology and psychiatry research there's a trend toward modeling symptom/behavioral presentations using "unsupervised" approaches. This is partially the impetus behind NIH RDoC, for example, and when you do this, you end up with similar but not identical constructs as DSM diagnoses. The recent DSM (DSM-5) was supposed to address this in part but got mired in politics. If you look at the actual results, by far the most important features in predicting future symptom state are previous values of those symptoms. So follow-up symptom A is best predicted by baseline symptom A. This autocorrelation importance is a sort of law of behavioral individual differences. The EEG variables are adding in the prediction, but relatively weakly, which further speaks to the central importance of the subjective variables, which is informationally mediating whatever is going on under the skull. This is really further underscored if you start thinking about things like this: are the EEG signals adding most to prediction of "physical" symptom improvement? There's also a literature about severity of symptoms; it's possible to make predictions of symptom response based on other criteria from previous studies and this paper does little to address that in a head-to-head comparison. K-fold cross validation is also good, but isn't the same as replicating something on entirely different sets of people with different sorts of heterogeneity due to unknown sources. It's an interesting paper but people need to be cautions about the hype that goes on in these areas (biological psychiatry and AI). |