On the behaviour of senile dementia patients vis-à-vis the mirror: Ajuriaguerra, Strejilevitch and Tissot (1963).

Mirror agnosia is the inability to use mirror knowledge when interacting with mirrors, while mirrored-self misidentification is the delusional belief that one's reflection in the mirror is a stranger. Ajuriaguerra, Strejilevitch, and Tissot (1963) conducted a detailed study of these two conditions before they became widely known in the English literature. We present a translation of this important paper. In their study, Ajuriaguerra et al. (1963) examined the behaviour of 30 dementia patients with respect to the mirror. Their examination focussed on three criteria: (1) recognition of own reflection; (2) use of reflected space; and (3) designation of parts of the body. The study found three distinct levels of impairment when interacting with mirrors. Patients with the most severe dementia were unable to recognise their own reflection and displayed the mirrored-self misidentification delusion. Patients with moderate dementia showed mirror agnosia. Finally, patients with mild dementia were unable to designate parts of their body in the mirror. These findings have important implications for understanding mirror agnosia and the mirrored-self misidentification delusion. In a commentary, we discuss the importance of the findings and place them within the context of subsequent research.