What Box: a task for assessing language lateralisation in young children

The assessment of active language lateralisation in infants and toddlers is challenging. It requires an imaging tool that is unintimidating, quick to setup, and robust to movement, in addition to an engaging and cognitively simple procedure that elicits language processing. Functional Transcranial Doppler Ultrasound (fTCD) offers a suitable technique and here we report on a suitable method to elicit active language production in young children. The 34-second ‘What Box’ trial presents an animated face ‘searching’ for an object. The face ‘finds’ a box that opens to reveal an object, which may be labelled spontaneously, in response to a “What’s this?” prompt, or in response to the object label. What Box conducted with 95 children (1 to 5 years-of-age, completing a median of 7 trials), who were left-lateralised on average. The task was validated (ρ = 0.4) against the gold standard Word Generation task in a group of older adults (n = 65, 60 to 85 years-of-age, median of 24 trials). Existing methods for assessing lateralisation of active language production have been used with 4-year-old children while passive listening has been conducted with sleeping 6-month-olds. This is the first active method to be successfully employed with infants, toddlers, and pre-schoolers, and show good correspondence to Word Generation in older adults.