Researchers from Boston University published results of 2 retrospective analyses of data from chronic persons with aphasia (PWA) who participated in treatment programs that targeted: [Study 1] naming performance (n = 41) optionally accompanied by sentence comprehension (n = 26); or [Study 2] naming performance alone (n = 41).  Before treatment, all of the study participants (n = 67) received a cognitive-linguistic battery; and 27 of Study 2 participants received further pretreatment non-linguistic cognitive assessments.  The goal of this work was to identify nonlinguistic cognitive factors associated with post-treatment outcome improvements in the targeted tasks.

Assessment instruments given to all 67 subjects comprised the Western Aphasia Battery–Revised, Boston Naming Test, Raven’s Pyramids & Palm Tree Test, and Cognitive Linguistic Quick Test.  10 additional assessments, including maze solution, design generation, digit span forward and backward, and others were administered to various subsets of participants.  Therapy was provided to subjects in 2-hour sessions, twice a week, over 10-12 weeks, in four different studies.  To quantify outcome language improvements, pre- and post-treatment scores were used to calculate individuals’ proportions of potential maximum gain (PMG) and potential maximum gain maintenance (PMGM) scores.  These were then correlated with 18 pretreatment cognitive test sub-scores to identify potential non-linguistic predictors of PMG and PMGM.

In Study 1, data analysis showed the just over 37% of participants scored beneath normal limits in non-linguistic cognitive assessments pretreatment.  These participants achieved an overall average of 53% of PMG in the treated tasks, with higher linguistic and higher non-linguistic cognitive function both significantly correlated with higher posttreatment PMG.  In Study 2, analysis revealed that among the non-linguistic cognitive functions assessed, higher scores in two particular domains – namely, executive function, and visual short-term memory – stood out in significantly predicting higher PMG after naming therapy, and also PMGM following cessation of naming therapy delivery.

This study begins to identify nonlinguistic cognitive domains that are candidate prognostic indicators for improvement in sentence comprehension and/or naming, following therapies that target those tasks.  Such findings complement a previously accumulated body of research that identifies ­– from linguistically-oriented assessment domains – other candidate prognostic indicators of post-intervention speech and language improvements.  All of these studies have been retrospective in nature, though – re-analyzing data that were gathered for purposes other than identifying prognostic indicators of responses to treatment in PWA.  Researchers must next initiate prospective studies to demonstrate applicability to practical clinical service delivery, and to expand the ranges of linguistic and non-linguistic phenomena studied.

For further reading:   N. Gilmore, E. L. Meier, J. P. Johnson, S. Kiran.  2019.  Nonlinguistic cognitive factors predict treatment-induced recovery in chronic poststroke aphasia.  Archives of Physical Medicine and Rehabilitation, 100(7):1251–1259, https://doi.org/10.1016/j.apmr.2018.12.024

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