Assessing executive functions in post-stroke aphasia-utility of verbally based tests

A multitasking assessment for aphasia: The Catalog Ordering Task

Multitasking assessments based on everyday scenarios are useful assessment tools that can reveal the consequences of language and cognitive impairments on functioning. Unfortunately, many existing multitasking assessments require a high degree of linguistic processing that may preclude their use with adults with aphasia. The purposes of this paper are to (1) describe the development of a multitasking assessment relevant to everyday activities, the Catalog Ordering Task (COT), specifically designed for aphasia, (2) investigate differences between the performances of adults without aphasia and adults with aphasia on the COT, and (3) explore the relationships between language and cognitive performances and the COT to facilitate clinical utility. Seventy-four participants, 40 adults with aphasia and 34 people without aphasia, completed the multitasking assessment in single and dual task conditions. The secondary task in the dual task condition was a tone detection task requiring a foot-pedal press. Participants with aphasia also completed additional language and cognitive assessments. We systematically developed the Catalog Ordering Test (COT) with considerations for semantics, syntax, and ecological validity. Criterion validity with acceptable levels of inter-rater and test-retest reliability were observed. Adults with aphasia performed with about half the accuracy and twice as slowly as people without aphasia. Adults with all severity levels of aphasia were able to complete the COT. Multitasking performance on the COT was related to impairment-level measures of language and cognition. The COT is a potentially clinically useful assessment of multitasking, specially designed for aphasia.

The Relationship Between Executive Functioning and Narrative Language Abilities in Aphasia

PURPOSE

Although individuals with aphasia commonly exhibit challenges in executive functioning (EF) and spoken discourse, there is limited research exploring connections between these abilities within this specific population. Therefore, this study investigated the relationship between verbal and nonverbal EF and narrative productions in aphasia using a multilevel linguistic approach.

METHOD

Participants included 22 persons with aphasia (PWA) and 24 age- and education-matched, neurologically healthy controls (NHC). All participants completed assessments for EF and a story retelling task. Narrative samples were analyzed for microlinguistic (productivity, lexical and syntactic features, semantic content, word and sentence errors) and macrolinguistic (coherence, informational content, organization, and language use) characteristics. Correlational analyses were employed to explore the relationships among narrative variables. EF factors, extracted from principal component analysis, were used as predictive variables in hierarchical stepwise regression analyses to evaluate their role in predicting narrative performances of PWA and NHC.

RESULTS

Relative to NHC, PWA exhibited impaired narrative performance affecting both microlinguistic and macrolinguistic levels. Breakdowns at the structural level (i.e., reduced productivity, syntax, lexical retrieval, and diversity) correlated with impaired story completeness, organization, and connectedness; this relationship was more prominent for PWA. Three EF factors representing (1) verbal EF, (2) verbal and nonverbal fluency, and (3) nonverbal EF were extracted. Factors 1 and 2 largely predicted narrative performance, whereas Factor 3 (i.e., nonverbal EF) contributed prominently to predicting macrolinguistic discourse performance in both groups although accounting for less variance in the data. Overall, lower EF scores, particularly verbal EF variables, predicted poor narrative performance in both groups.

CONCLUSIONS

Our results indicate that both linguistic and extralinguistic cognitive abilities play a role in story retelling performances among PWA. Notably, both verbal and nonverbal EF skills were found to be correlated with narrative abilities. However, the extent of their contributions varied depending on the discourse levels assessed. These findings provide a significant contribution to our understanding of the cognitive factors associated with breakdowns in discourse among PWA and highlight the importance of comprehensive assessment of EF and discourse within this population.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.26485627.

Assessing processing speed and its neural correlates in the three variants of primary progressive aphasia with a non-verbal tablet-based task

Prior research has revealed distinctive patterns of impaired language abilities across the three variants of Primary Progressive Aphasia (PPA): nonfluent/agrammatic (nfvPPA), logopenic (lvPPA) and semantic (svPPA). However, little is known about whether, and to what extent, non-verbal cognitive abilities, such as processing speed, are impacted in PPA patients. This is because neuropsychological tests typically contain linguistic stimuli and require spoken output, being therefore sensitive to verbal deficits in aphasic patients. The aim of this study is to investigate potential differences in processing speed between PPA patients and healthy controls, and among the three PPA variants, using a brief non-verbal tablet-based task (Match) modeled after the WAIS-III digit symbol coding test, and to determine its neural correlates. Here, we compared performance on the Match task between PPA patients (n = 61) and healthy controls (n = 59) and across the three PPA variants. We correlated performance on Match with voxelwise gray and white matter volumes. We found that lvPPA and nfvPPA patients performed significantly worse on Match than healthy controls and svPPA patients. Worse performance on Match across PPA patients was associated with reduced gray matter volume in specific parts of the left middle frontal gyrus, superior parietal lobule, and precuneus, and reduced white matter volume in the left parietal lobe. To conclude, our behavioral findings reveal that processing speed is differentially impacted across the three PPA variants and provide support for the potential clinical utility of a tabled-based task (Match) to assess non-verbal cognition. In addition, our neuroimaging findings confirm the importance of a set of fronto-parietal regions that previous research has associated with processing speed and executive control. Finally, our behavioral and neuroimaging findings combined indicate that differences in processing speed are largely explained by the unequal distribution of atrophy in these fronto-parietal regions across the three PPA variants.

Targeted neurorehabilitation strategies in post-stroke aphasia

BACKGROUND

Aphasia is a debilitating language impairment, affecting millions of people worldwide. About 40% of stroke survivors develop chronic aphasia, resulting in life-long disability.

OBJECTIVE

This review examines extrinsic and intrinsic neuromodulation techniques, aimed at enhancing the effects of speech and language therapies in stroke survivors with aphasia.

METHODS

We discuss the available evidence supporting the use of transcranial direct current stimulation (tDCS), repetitive transcranial magnetic stimulation, and functional MRI (fMRI) real-time neurofeedback in aphasia rehabilitation.

RESULTS

This review systematically evaluates studies focusing on efficacy and implementation of specialized methods for post-treatment outcome optimization and transfer to functional skills. It considers stimulation target determination and various targeting approaches. The translation of neuromodulation interventions to clinical practice is explored, emphasizing generalization and functional communication. The review also covers real-time fMRI neurofeedback, discussing current evidence for efficacy and essential implementation parameters. Finally, we address future directions for neuromodulation research in aphasia.

CONCLUSIONS

This comprehensive review aims to serve as a resource for a broad audience of researchers and clinicians interested in incorporating neuromodulation for advancing aphasia care.

Attention to attention in aphasia - elucidating impairment patterns, modality differences and neural correlates

It is increasingly acknowledged that patients with aphasia following a left-hemisphere stroke often have difficulties in other cognitive domains. One of these domains is attention, the very fundamental ability to detect, select, and react to the abundance of stimuli present in the environment. Basic and more complex attentional functions are usually distinguished, and a variety of tests has been developed to assess attentional performance at a behavioural level. Attentional performance in aphasia has been investigated previously, but often only one specific task, stimulus modality, or type of measure was considered and usually only group-level analyses or data based on experimental tasks were presented. Also, information on brain-behaviour relationships for this cognitive domain and patient group is scarce. We report detailed analyses on a comprehensive dataset including patients' performance on various subtests of two well-known, standardised neuropsychological test batteries assessing attention. These tasks allowed us to explore: 1) how many patients show impaired performance in comparison to normative data, in which tasks and on what measure; 2) how the different tasks and measures relate to each other and to patients' language abilities; 3) the neural correlates associated with attentional performance. Up to 32 patients with varying aphasia severity were assessed with subtests from the Test of Attentional Performance (TAP) as well as the Test of Everyday Attention (TEA). Performance was compared to normative data, relationships between attention measures and other background data were explored with principal component analyses and correlations, and brain-behaviour relationships were assessed by means of voxel-based correlational methodology. Depending on the task and measure, between 3 and 53 percent of the patients showed impaired performance compared to normative data. The highest proportion of impaired performance was noted for complex attention tasks involving auditory stimuli. Patients differed in their patterns of performance and only the performance in the divided attention tests was (weakly) associated with their overall language impairment. Principal components analyses yielded four underlying factors, each being associated with distinct neural correlates. We thus extend previous research in characterizing different aspects of attentional performance within one sample of patients with chronic post stroke aphasia. Performance on a broad range of attention tasks and measures was variable and largely independent of patients' language abilities, which underlines the importance of assessing this cognitive domain in aphasic patients. Notably, a considerable proportion of patients showed difficulties with attention allocation to auditory stimuli. The reasons for these potentially modality-specific difficulties are currently not well understood and warrant additional investigations.