Adrian Owen et al. in 'Detecting Awareness in the Vegetative State' (2008) have used fMRI (Functional Magnetic Resonance Imaging) activation patterns of neural activity as a supportive evidence to claim that a patient who previously was assumed to be in a vegetative state has intentional agency. However, it is questionable if such an approach and evidence is sufficient to conclude so.
This question can be tackled at least from two aspects: its rationale and its implication. I will discuss both as my outlook differs on these two aspects. Owen’s work tries to answer this question that whether observing normal brain activities while performing mental imaginary tasks, similar to what that is observable in healthy people, in patients who are diagnosed as being in vegetative state show any kind or level of consciousness.
Based on the logic he provided in the article, I think that such brain activities can show that the patient has some kind of awareness or consciousness, knowing that other experiments, as he mentioned, reject the objection that the used words (e.g. tennis and house) can automatically trigger the brain activities, supports this claim. It means that if empirical studies support this claim that similar fMRI activation patterns shows similar kind and level of awareness then fMRI will be sufficient to assess the state of consciousness of patients who suffers disorder of consciousness or more specifically vegetative state. However, Owen’s work does not provide strong evidence, neither statistically nor methodologically, in support of his claim. The article mainly relied on a single patient with a few observations and only with two patterns: playing tennis and walking through rooms.