A new instrument for the assessment of laterality: evidence from confirmatory analysis

Despite its importance, the assessment of laterality in scientific and clinical contexts remains inconsistent. Many studies rely on self-reports or outdated questionnaires (in terms of daily-related actions), often neglecting lateralization of the lower limbs, eyes, and ears without considering the four effectors at the same time. To address these limitations, we developed the Florence Laterality Inventory (FLI), a 16-item scale designed to provide a comprehensive assessment of hand, foot/leg, eye, and ear preference through more contemporary and relevant questions. Our study, conducted with 225 participants, confirmed a four-factor structure through confirmatory factor analysis (CFA), demonstrating good reliability for the hand, eye, and ear subscales and, to a lesser extent, also for foot/leg. Correlations with established measures of laterality and handedness supported the concurrent validity of the scale. The FLI scale offers an updated multidimensional instrument to measure lateralization, addressing the shortcomings of previous questionnaires and adapting to modern contexts.