The aim of this study was to review the usefulness of clinical and instrumental evaluation in individuals with disorders of consciousness (DOC). Thirteen subjects with severe acquired brain injury (ABI) and a diagnosis of DOC were evaluated using the Coma Recovery Scale in its revised version (CRS-R) and a new global disability index, the Post-Coma Scale (PCS). These instruments were administered both by a neutral examiner (professional) and by a professional in the presence of a caregiver. All patients were also scored using the International Classification of Functioning, Disability and Health (ICF). A statistically significant correlation between CRS-R and PCS was demonstrated. However, there also emerged significant differences in responsiveness between professional versus caregiver+professional assessment using the two scales. The emotional stimulation provided by significant others (caregivers) during administration of DOC evaluation scales may improve the assessment of responsiveness.