Outcomes of semantic feature analysis treatment for aphasia with and without apraxia of speech

To date, studies have not explored whether a dual diagnosis of aphasia plus apraxia of speech (AOS) versus aphasia alone (APH) affects the response to language-based naming treatments.

To compare the effects of semantic feature analysis (SFA) treatment for individuals with APH versus aphasia plus AOS, and to test if the presence of AOS impacted the effects of treatment.

A non-randomized experimental group study was conducted to explore the treatment, generalization and maintenance effects between the AOS and APH groups. Participants included nine individuals with aphasia and 11 with concomitant aphasia and AOS. Dependent measures included lexical accuracy, number of sound-level distortions, and lexical stress and syllable segmentation errors.

Both groups showed significantly improved naming accuracy of trained items for up to 2 months post-treatment. Improvement on naming accuracy of untrained items post-treatment, both semantically related and unrelated to trained items, was lower in magnitude. That this may have been due to effects of repeated probing (which included target repetition) or regression to the mean cannot be excluded. There was a tendency for the AOS group to respond slightly better to treatment than the APH group overall, which was not correlated with aphasia severity. Also, measures of phonetic accuracy and fluency improved for both groups, with no main effect of group. Treatment effects did not generalize to formal measures of (untrained) picture naming or expression of correct information units in discourse in a story retelling task.

Findings indicate that individuals with aphasia plus AOS can gain equivalent benefits in word retrieval and production from the language-based SFA treatment as individuals with aphasia alone. This may be, in part, due to the tendency for SFA to incorporate principles of practice that are known to support motor learning in AOS, such as high intensity, random stimulus presentation and variable practice. Findings provide further support for high-intensity practice and use of self-generated features to facilitate maintenance of effects. What this paper adds What is already known on the subject SFA treatment is the most common intervention for word-finding difficulties for individuals with aphasia. AOS is a common concomitant disorder to aphasia. However, it is not clear whether the effects of language-based SFA treatment are mitigated by the presence of AOS, which tends to respond well to treatments focused on articulatory-kinematic aspects of speech movement. What this paper adds to the existing knowledge This study compares the effects of SFA in a group of individuals with aphasia alone and a group with similar severity of aphasia but with concomitant AOS, ranging from mild to moderate-severe. Overall, AOS did not have a negative effect on response to the treatment. What are the potential or actual clinical implications of this work? Individuals with aphasia plus AOS can be expected to benefit to a similar degree from SFA as people with aphasia alone. It is likely that the use of practice principles of high intensity, random stimulus presentation and varied practice are important components of the protocol.