Neurological observations are an essential aspect of assessment in patients with altered mental status and require the nurse to collect and analyse information using a validated assessment tool. Assessing a patient’s pupil size and response is also an important element of a neurological assessment. This article summarises the pathophysiology of raised intracranial pressure and lists some of the conditions that may contribute to an alteration in a patient’s mental status. The article details the use of two commonly used neurological assessment tools and the assessment of a patient’s pupil size and response. The author also considers the challenges related to accurate recording of neurological observations.