The role of input vs. output phonological working memory in narrative production: Evidence from case series and case study approaches.

Separable input and output phonological working memory (WM) capacities have been proposed, with the input capacity supporting speech recognition and the output capacity supporting production. We examined the role of input vs. output phonological WM in narrative production, examining speech rate and pronoun ratio - two measures with prior evidence of a relation to phonological WM. For speech rate, a case series approach with individuals with aphasia found no significant independent contribution of input or output phonological WM capacity after controlling for single-word production. For pronoun ratio, there was some suggestion of a role for input phonological WM. Thus, neither finding supported a specific role for an output phonological buffer in speech production. In contrast, two cases demonstrating dissociations between input and output phonological WM capacities provided suggestive evidence of predicted differences in narrative production, though follow-up research is needed. Implications for case series vs. case study approaches are discussed.

Semantic Working Memory Predicts Sentence Comprehension Performance: A Case Series Approach.

Sentence comprehension involves maintaining and continuously integrating linguistic information and, thus, makes demands on working memory (WM). Past research has demonstrated that semantic WM, but not phonological WM, is critical for integrating word meanings across some distance and resolving semantic interference in sentence comprehension. Here, we examined the relation between phonological and semantic WM and the comprehension of center-embedded relative clause sentences, often argued to make heavy demands on WM. Additionally, we examined the relation between phonological and semantic WM and the comprehension of transitive and dative active and passive sentences, which may also draw on WM resources depending on the number of propositions that must be maintained and the difficulty of processing passive clauses. In a large sample of individuals with aphasia (N = 56), we assessed whether comprehension performance on more complex vs. simpler active-passive or embedded relative clause sentences would be predicted by semantic but not phonological WM when controlling for single word comprehension. For performance on the active-passive comprehension task, we found that semantic WM, but not phonological WM, predicted comprehension of dative sentences when controlling for comprehension of transitive sentences. We also found that phonological WM, but not semantic WM, predicted mean comprehension for reversible active-passive sentences when controlling for trials with lexical distractors. On the relative clause comprehension task, consistent with prior results, we found that semantic WM, but not phonological WM, predicted comprehension of object relative clause sentences and relative clause sentences with a passive construction. However, both phonological WM and semantic WM predicted mean comprehension across all relative clause types for reversible trials when controlling for trials with lexical distractors. While we found evidence of semantic WM's role in comprehension, we also observed unpredicted relations between phonological WM and comprehension in some conditions. Post-hoc analyses provided preliminary evidence that phonological WM maintains a backup phonological representation of the sentence that may be accessed when sentence comprehension processing is less efficient. Future work should investigate possible roles that phonological WM may play across sentence types.

Contributions of semantic and phonological working memory to narrative language independent of single word production: Evidence from acute stroke.

ABSTRACTNeuropsychological case studies have provided evidence that individuals with semantic, but not phonological, working memory (WM) deficits have difficulty producing phrases containing several content words. These findings supported the claim of a phrasal scope of planning at the grammatical formulation stage of production, where semantic WM supports the maintenance of lexical-semantic representations as they are inserted into slots in phrasal constituents. Recent narrative production results for individuals at the acute stage of stroke supported the role for semantic WM in phrasal elaboration while suggesting a role for phonological WM at a subsequent phonological encoding stage in supporting fluent, rapid speech. In the present study, we employed a larger participant sample while controlling for single word production abilities at semantic and phonological levels. Results confirmed the relations between semantic WM and phrasal elaboration whereas the relation between phonological WM and speech rate was eliminated. There was, however, evidence that both impaired phonological retrieval and restricted phonological WM were related to the tendency to produce short, highly frequent words such as pronouns rather than longer, less frequent words. Future research is needed to address whether the results relating to phonological WM depend on damage specific to an output rather than an input phonological capacity.

Applying a Model of Stakeholder Engagement to a Pragmatic Trial for People With Mental Disorders.

Stakeholder engagement is an important component of pragmatic trials seeking to improve mental health care in real-world settings. Models of stakeholder engagement outline the benefits of involving a diverse array of partners in all phases of research. This column describes a stakeholder engagement plan for a comparative-effectiveness pragmatic trial of a care navigator program to increase linkage between emergency departments and outpatient treatment at community mental health centers. Benefits of stakeholder engagement include meaningful input on program design and implementation, insights into balancing the need for flexibility among clinical sites while implementing the program with fidelity, and early discussions about program sustainability and dissemination.