Chew on this! Oral stereognosis predicts visual word recognition in typical adults

Much work has been conducted that reports on the strong relationships between speech production and reading behaviour. However, disentangling the relative contribution of the various underlying speech mechanisms (i.e., articulation, somatosensory and/or auditory) that contribute to this relationship remains unknown. Oral stereognosis refers to the ability to discriminate shapes using our tongue/mouth, in the absence of seeing the shape beforehand, and is a measure of the somatosensory sub-system of the speech mechanism. In this work, we aimed to address the extent to which oral stereognosis predicted visual word recognition. Methods: Healthy participants ranging from 18 to 51 years old ( N = 60; M age = 22.7) completed the Florida Oral Recognition Measurement (FORM) task and two visual word recognition tasks. The FORM required participants to identify carrots that were cut into the following letters’ shapes: E, R, T, S, L, N, O, V. Carrot letters were randomly presented to participants. With respect to the visual word recognition tasks, participants were required to press a button: 1) if the letter string spelled a word or 2) if the letter string sounded like a word. Response time and accuracy were measured for all tasks. Results: Participants were divided into high (accuracy >50%) vs. low (accuracy ≦ 50%) oral stereognosis recognition groups. For the high FORM group, oral stereognosis recognition predicted visual word recognition in the spell task (Adj R 2 = .114). For the low FORM group, oral stereognosis recognition predicted visual word recognition in the sound task (Adj R 2 = .307). Together, these findings provide evidence that oral stereognosis is predictive of word recognition performance, and that performance on the FORM differentially predicts word recognition tasks (spell vs. sound). Overall, these findings inform current print-to-speech frameworks by identifying a relationship between sensorimotor information, specifically, oral stereognosis ability, and reading performance.