Group-item and directed scanning: examining preschoolers' accuracy and efficiency in two augmentative communication symbol selection methods.

Purpose: The current investigation compared directed scanning and group-item scanning among typically developing 4-year-old children. Of specific interest were their accuracy, selection speed, and efficiency of cursor movement in selecting colored line drawn symbols representing object vocabulary.

Method: Twelve 4-year-olds made selections in both directed and group-item scanning conditions using a 36-symbol array that required matching line drawn symbols to pictures.

Results: The majority of participants took more time in the directed scanning condition. Though not statistically significant, participants tended to be more accurate in their use of directed scanning. The cursor movements required (as a proportion of optimal cursor movements) were similar for both scanning selection techniques.

Conclusions: Among typically developing 4-year-olds, there appears to be a trade-off between speed and accuracy in symbol selection when using directed or group-item scanning. Better accuracy with directed scanning appears to come at the cost of a slower response time. Whereas group-item scanning may be faster, it results in a decreased number of accurate responses. Applications for clinical practice and implications for future research are discussed.