American Board of Psychiatry and Neurology (ABPN) Practice Exam 2025 - Free ABPN Practice Questions and Study Guide

In a persistent vegetative state (PVS), a key characteristic that is typically absent is the ability to respond purposefully or meaningfully to stimuli, which includes the response to noxious stimuli. Patients in PVS may exhibit reflexive movements or responses, but these do not indicate conscious awareness or purposeful action.

In this state, individuals may still show preserved eye opening, meaning they can open their eyes, but it does not imply cognitive awareness. They may also demonstrate sleep-wake cycles, showing periods of apparent wakefulness and rest, which can mislead observers into thinking they are responsive. Eye tracking, or the ability to follow objects with the eyes, is not typically present in PVS; instead, any seeming visual engagement is often a reflexive behavior rather than a directed response.

Thus, while some basic reflexive actions may remain, the absence of meaningful response to stimuli is a defining aspect of a persistent vegetative state.