Can anyone find any explanation for how the researcher might have controlled for deception in this kind of study? The linked article mentions that they did cont

Can anyone find any explanation for how the researcher might have controlled for deception in this kind of study? The linked article mentions that they did control for delusional beliefs about the identities of the faces the individual was perceiving - this helps reject the hypothesis that this is part of a larger psychiatric issue. But the journal link does not discuss how the researcher rejects the hypothesis that the individual could be fabricating the experience. It could also be the case that the researcher helped fabricate the results to produce work - a risk created in part by the unending pressure of publish/perish. Obviously it would be very unfair to assume that either patient or researcher are deceptive here, given that it's far more likely that both patient and researcher simply want to help people with this condition. I do not want to call the researcher into question, and much less do I want to invalidate the patient's experience. But I'm curious about how we should approach this with healthy skepticism in the age of the replicability crisis - what specific signals do you use to confirm the likely veracity of the researcher and subject, given the very subjective and unblinded nature of the case study, and lack of discussion on how we discard the deceptive hypothesis? Did you find details that I'm missing? And if you assign a percentage to your confidence in this result, what percentage is it, and why?