Influence of order of stimulus presentation on speech motor learning: A principled approach to treatment for apraxia of speech

The present study was designed to examine whether applying principles of mo tor learning to a commonly used treatment approach for acquired apraxia of speech (AOS) would enhance relearning of speech production skills. In parti cular, we examined one main principle, random practice, and compared it to blocked practice. Of importance is the fact that many speech treatments uti lize blocked practice, but the literature on motor learning clearly shows t hat blocked practice facilitates acquisition of target behaviours, but not retention and transfer. The latter two are considered true indices of learn ing. In two subjects with severe AOS, results showed that random practice f acilitated retention whereas blocked practice did not. The present study pr ovides preliminary evidence that these principles may have a similar effect on learning of skilled speech motor acts as they do on learning of limb mo vements. The results reported here are encouraging and provide justificatio n and focus for further investigation.