Despite the general assumption that completely locked-in state (CLIS) patients remain conscious and aware of their environment, the effectiveness of brain-computer interfaces (BCIs) in facilitating communication has been limited, as reported both in the literature and in our own findings. This limitation is likely attributable to impairments in executive functions, working memory, and vigilance, which appear to hinder the establishment of reliable BCI-based communication. The main goal of this research is to develop a neurophysiological report designed to support the evaluation of the cognitive state of these individuals and determine their ability to interact with BCIs. To achieve this, we designed a set of paradigms to assess CLIS patients at the reflexive and perceptual levels, based on neural responses associated with sensory and perceptual processing, including Mismatch Negativity (MMN), Steady State Auditory Evoked Potential (SSAEP), and Steady State Visual Evoked Potential (SSVEP). Pilot testing with five healthy participants demonstrates the feasibility of generating a neurophysiological report for cognitive assessment at both levels.