Background: Impaired self-awareness (ISA) has frequently been found to be both frequent and deleterious in patients with moderate to severe traumatic brain injury (TBI).

Objectives: The present paper is the first of a two-part systematic review of ISA after traumatic brain injury (TBI), focusing on assessment methods, clinical aspects and recovery.

Methods: Following the PRISMA guidelines, 95 articles meeting the inclusion criteria were included.

Results: ISA occurs in 30% to 50% of patients with moderate to severe TBI, although it tends to improve with time. There is no one single gold-standard measure of ISA. Self-proxy discrepancy scores, with scales such as the Patient Competency Rating Scale or the Awareness Questionnaire, or a structured interview such as the Self Awareness of Deficits Interview, are the most frequently used assessment methods, with adequate psychometric properties. Scores on these different scales correlate only moderately with each other, which suggests that they may address different aspects of self-awareness. ISA mainly concerns cognitive and behavioral problems rather than physical or sensory impairments and may concern different areas of functioning, such as anticipatory, emergent or meta-cognitive awareness.

Conclusion: ISA is a complex and multifaceted issue that should be systematically assessed in rehabilitation settings using a range of relatively well-validated tools. The consequences and predictors of ISA after TBI will be addressed in a companion paper.