Developmental prosopagnosia in Poland: an analysis of online-conducted population based study

Abstract

Background and aim of the study: Developmental prosopagnosia (DP) is defi ned as
impaired face recognition in the absence of brain injury or intellectual defi cit. Because
of the complexity of validated face memory and perception tests, its online distribution
greatly improves the effectiveness and convenience of conducting research. Assessment
of DP occurrence in the Polish population concerning study sample collection and
characteristics.
Material and methods: An online questionnaire consisting of the 20-item Prosopagnosia
Index (PI20) was administered to assess self-reported problems with face recognition.
Cambridge Face Memory Test (CFMT) and Glasgow Face Matching Test (GFMT)
were applied to assess respondents’ face memory and perception. Additional data on
respondents’ gender, age and handedness were also obtained. All of the components were
arranged together using Google Forms tool. Respondents were recruited via social media
announcements. The study was conducted from 1st January to 31st March 2019. Each of
the respondents was provided with personalised results analysis, which was sent with an
e-mail. They were also able to stay in contact with research authors, asking additional questions
and giving remarks.
Results: During the study, a total of 1349 questionnaires were collected, out of which
1276 met inclusion criteria and were enrolled in the study. 66.1% of the respondent group
were females and 33.9% males. The mean age was 28.3 ± 9.5 years (range: 14-75). The
mean PI20 score was 49.6 ± 18 (range: 20-99). In 11.8% of respondents PI20 result indicated
self-reported mild, in 8.3% moderate and in 3.9% severe DP. The mean CFMT total
score was 58.1 (median: 59, range: 26-72) and mean GFMT score was 33.9 (median: 34,
range: 18-40). According to the cutoff values from original papers, 81 (6.3%) of respondents
scored below threshold in CFMT, 27 (2.4%) in GFMT. Out of 50 respondents who
self-reported symptoms indicating severe DP, only 15 (30%) scored below the cutoff in
CFMT and 6 (12%) in GFMT. On the contrary, 30 (3.1%) and 16 (1.4%) out of 970 respondents
reporting no problems with face recognition had total scores below the cutoff in
CFMT and GFMT, respectively.
Conclusions: The estimated prevalence of developmental prosopagnosia in Polish
population is higher than in normative data. These discrepancies may result from specifi c
demographics of participant group more than an online-character of the study. It is

important to focus on experiment design and methodology in order to maintain high quality of
collected data. Development of country-specifi c norms and stimuli for face-recognition
tests should also be considered .