Smooth Pursuit Eye Tracking in Twins:A Critical Commentary

Abstract

LITMAN ET al1 conducted a study of smooth pursuit eye movements in monozygotic (MZ) twins discordant for schizophrenia. Although their data show a high concordance for eye tracking among pairs of clinically discordant twins with schizophrenia, confirming previous twin studies of eye tracking,2,3 they conclude that eye tracking dysfunction (ETD) is an outcome of having schizophrenia but does not represent a potential genetic indicator. We believe that this is an unwarranted conclusion and address this issue and other serious flaws in their design and interpretation.SAMPLE AND SAMPLE SIZE Litman et al compared 12 pairs of MZ twins discordant for schizophrenia with 12 pairs of MZ "normal" twins..