Practice effects in healthy older adults: Implications for treatment-induced neuroplasticity in Aphasia

Neural correlates of object and action naming practice

Word retrieval deficits are a common problem in patients with stroke-induced brain damage. While complete recovery of language in chronic aphasia is rare, patients' naming ability can be significantly improved by speech therapy. A growing number of neuroimaging studies have tried to pinpoint the neural changes associated with successful outcome of naming treatment. However, the mechanisms supporting naming practice in the healthy brain have received little attention. Yet, understanding these mechanisms is crucial for teasing them apart from functional reorganization following brain damage. To address this issue, we trained a group of healthy monolingual Italian speakers on naming pictured objects and actions for ten consecutive days and scanned them before and after training. Although activity during object versus action naming dissociated in several regions (lateral occipitotemporal, parietal and left inferior frontal cortices), training effects for the two word classes were similar and included activation decreases in classical language regions of the left hemisphere (posterior inferior frontal gyrus, anterior insula), potentially due to decreased lexical selection demands. Additionally, MVPA revealed training-related activation changes in the left parietal and temporal cortices associated with the retrieval of knowledge from episodic memory (precuneus, angular gyrus) and facilitated access to phonological word forms (posterior superior temporal sulcus).

Test-retest reliability in an fMRI study of naming in dementia

fMRI has been used as an outcome measure in dementia treatment studies, with many previous studies comparing only single pre- and post-treatment fMRI scans to determine treatment-induced neural changes, while utilizing single subject experimental designs. The purpose of the current study was to evaluate fMRI test-retest reliability in dementia patients and typical older adults using noun and verb confrontation naming to evaluate the validity of using a single pre/post-treatment scan comparison. Seven individuals with dementia and 9 control participants were tested three times over two months using the same fMRI procedures. Differences in individual and group level activation patterns were observed that varied across time. Additionally, the extent of variability fluctuated across individuals, groups, and the grammatical category of target words. Our findings suggested that one time fMRI scanning may inadequately represent an individual's typical brain activation pattern, particularly an individual with dementia. Thus, multiple imaging baselines are recommended.

Effects of a Tablet-Based Home Practice Program With Telepractice on Treatment Outcomes in Chronic Aphasia

Purpose

The aim of this study was to determine if a tablet-based home practice program with weekly telepractice support could enable long-term maintenance of recent treatment gains and foster new language gains in poststroke aphasia.

Method

In a pre-post group study of home practice outcomes, 21 individuals with chronic aphasia were examined before and after a 6-month home practice phase and again at follow-up 4 months later. The main outcome measure studied was change in naming previously treated or untreated, practiced or unpracticed pictures of objects and actions. Individualized home practice programs were created in iBooks Author with semantic, phonemic, and orthographic cueing in pictures, words, and videos in order to facilitate naming of previously treated or untreated pictures.

Results

Home practice was effective for all participants with severity moderating treatment effects, such that individuals with the most severe aphasia made and maintained fewer gains. There was a negative relationship between the amount of training required for iPad proficiency and improvements on practiced and unpracticed pictures and a positive relationship between practice compliance and same improvements.

Conclusion

Unsupervised home practice with weekly video teleconferencing support is effective. This study demonstrates that even individuals with chronic severe aphasia, including those with no prior smart device or even computer experience, can attain independent proficiency to continue practicing and improving their language skills beyond therapy discharge. This could represent a low-cost therapy option for individuals without insurance coverage and/or those for whom mobility is an obstacle to obtaining traditional aphasia therapy.