A persistent vegetative state (PVS) is a disorder of consciousness in which patients with severe brain damage are in a state of partial arousal rather than true awareness. After four weeks in a vegetative state (VS), the patient is classified as in a persistent (or 'continuing') vegetative state. This diagnosis is classified as a permanent vegetative state some months (3 in the US and 6 in the UK) after a non-traumatic brain injury or one year after a traumatic injury. Nowadays, more doctors and (neuro)scientists prefer to call the state of consciousness an unresponsive wakefulness syndrome, primarily because of ethical questions about whether a patient can be called 'vegetative' or not.