Background. One of the main subdomains of social cognitive functions, Theory of Mind (ToM), involves the ability to understand other people’s thoughts, intentions, emotions, and predict their behaviour. ToM deficit is common in many neurological and mental disorders. So far, there have been no measures assessing ToM functions adapted to the Lithuanian-speaking population.
Objective. To translate and perform a linguistic and cultural adaptation of two ToM tests – the Faux Pas Recognition test and Happé Strange Stories test – to the Lithuanian-speaking population and to evaluate their psychometric properties.
Materials and methods. Both instruments were translated from English into Lithuanian and from Lithuanian into English. A total of 100 adult subjects were tested using Lithuanian test variants. The reliability and validity of the instruments were evaluated. Internal consistency was estimated by calculating the Cronbach α coefficient, the inter-rater reliability by the intraclass correlation coefficient, and the convergent construct validity by the Spearman correlation coefficient.
Results. The Cronbach α coefficient for the faux pas stories of the Faux Pas Recognition test was 0.815, for the control stories 0.426, and for the Strange Stories test 0.708. The intraclass correlation coefficient of the faux pas stories of the Faux Pas Recognition test was 0.996, and that of the Strange Stories test was 0.911. There was a statistically significant weak positive correlation between the Strange Stories test and the faux pas stories ratings (r=0.355, p=0.045), but the control stories of the Faux Pas Recognition test did not statistically significantly correlate with the faux pas stories (r=0.033, p=0.745) and Happé Strange Stories test (r=0.109, p=0.282). The face and content validity of both instruments was good.
Conclusions. The Faux Pas Recognition test and Happé Strange Stories test are adapted to the Lithuanian-speaking population. Both instruments can be useful in evaluating social cognitive functions.