In 2015, Shah et al published the 20-item prosopagnosia index, also called “The PI20”, a self-report instrument for identifying developmental prosopagnosia.
In the study, participant’s face recognition abilities were assessed with face recognition tests, such as the CFMT, and other visual perception tasks were applied. Additionally, participants were also asked to answer and rate 20 questions. By comparing results from the questionnaire and perception tasks, the researchers were able to show a correlation between the two approaches of assessment.
This quickly answered 20-item questionnaire can help with identification of potential developmental face blindness. If you would like to read more about the author’s work, you can find more information here.