Reading for Meaning: The Influence of Reader Characteristics on Paragraph Understanding in Aphasia

PURPOSE

The study improves our understanding of the reading comprehension difficulties seen in people with aphasia. It investigates the influence of reader characteristics, including personal demographic variables, and linguistic and wider cognitive skills, on text comprehension.

METHOD

Seventy-five people with aphasia and 87 neurologically typical readers completed a test of paragraph comprehension. People with aphasia also completed background tests of language, attention, recognition memory, and executive functions. The influence of demographic variables (age, gender, and level of education) was analyzed separately in the group of people with aphasia and the typical readers using analyses of variance. In the people with aphasia, the relationship between paragraph comprehension and the language and cognitive tests was explored using correlational analyses.

RESULTS

In the typical readers, there was a significant effect of gender and level of education and a significant three-way interaction. For the people with aphasia, there were no significant effects of demographic variables. Significant positive correlations were found between performance on paragraph comprehension and each of the language tests and with tests of auditory attention, executive functions, and recognition memory for words.

CONCLUSIONS

In people with aphasia, the effects of demographic variables were overshadowed by the effect of their language difficulties. The association seen across language measures reflects the shared semantic representations across single-word, sentence, and text levels, across modalities. The study emphasizes the importance of attention, executive functions, and short-term memory in the comprehension of and memory for what we read. The contribution of both language difficulties and wider cognitive skills needs to be considered when planning intervention.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.24695451.

Semantic impairment in aphasia: A problem of control?

PURPOSE

The relationship between cognitive processes and language ability in aphasia has recently gained increasing attention, with some authors suggesting that control impairments may underlie difficulties with semantic tasks in aphasia. This paper aims to present an overview of the current research on the involvement of cognitive processes in semantic processing tasks and discuss the proposed relationship between cognitive control and semantic processing in aphasia.

METHOD

The role of cognitive processes in semantic processing tasks commonly used in the aphasiology literature is discussed and two theoretical approaches to semantic processing that contribute to the understanding of the nature of semantic breakdown in aphasia are outlined. Finally, we examine the evidence put forward in the Controlled Semantic Cognition framework with regard to the interpretation of impaired performance on semantic processing tasks in people with aphasia.

RESULT

Non-linguistic cognitive abilities such as working memory, inhibition and control are required by semantic processing tasks, in addition to access to conceptual information, making it difficult to dissociate these abilities. Several issues exist regarding the evidence put forward for a control deficit as the underlying cause of poor performance on semantic processing tasks in aphasia.

CONCLUSION

It remains unclear whether impairment on semantic tasks in people with aphasia is related to problems with the representation and/or processing (activation/retrieval) of meaning or problems with cognitive control (or both). Further research is still needed to fully understand how non-linguistic cognitive processes interact with semantic processing, as well as clarify and consistency the definition of control.

Language-Specific Dual-Task Effects After Stroke: A Systematic Review

PURPOSE

The dual-task paradigm has been frequently used to examine stroke-related deficits because it samples behavioral performance under conditions of distraction similar to functioning in real-life environments. This original systematic review synthesizes studies that examined dual-task effects involving spoken language production in adults affected by stroke, including transient ischemic attack (TIA) and poststroke aphasia.

METHOD

Five databases were searched (inception to March 2022) for eligible peer-reviewed articles. The 21 included studies reported a total of 561 stroke participants. Thirteen studies focused on single word production, for example, word fluency, and eight on discourse production, for example, storytelling. Most studies included participants who had suffered a major stroke. Six studies focused on aphasia, whereas no study focused on TIA. A meta-analysis was not appropriate because of the heterogeneity of outcome measures.

RESULTS

Some single word production studies found dual-task language effects whereas others did not. This finding was compounded by the lack of appropriate control participants. Most single word and discourse studies utilized motoric tasks in the dual-task condition. Our certainty (or confidence) assessment was based on a methodological appraisal of each study and information about reliability/fidelity. As 10 of the 21 studies included appropriate control groups and limited reliability/fidelity information, the certainty of the findings may be described as weak.

CONCLUSIONS

Language-specific dual-task costs were identified in single word studies, especially those that focused on aphasia as well as half of the nonaphasia studies. Unlike single word studies, nearly all studies of discourse showed dual-task decrements on at least some variables.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.23605311.

Sentence Production in a Discourse Context in Latent Aphasia: A Real-Time Study

PURPOSE

The purpose of this study was to improve our understanding as to which factors determine online, spoken sentence production abilities of adults with latent aphasia in a discourse context.

METHOD

Discourse samples of the story of Cinderella elicited from AphasiaBank were analyzed with speech analysis software. Participants comprised people with latent and anomic aphasia as well as neurotypical controls (10 per group). Durations of pauses (silent and filled) were analyzed according to (a) the location they occurred (between or within sentences), (b) the syntactic complexity of sentences (simple, complex), and (c) sentence length (number of words). Statistical comparisons were conducted using mixed-effect models.

RESULTS

The two clinical groups (latent and anomic) differed from controls in the duration of pauses, both between and within sentences. Syntactic complexity did not exert an effect on either of the two clinical groups as compared with controls. As compared with controls, both clinical groups paused more before long in comparison with short sentences.

CONCLUSION

Reduction in processing speed, which affects the ability to simultaneously maintain multiple linguistic and other cognitive demands associated with planning and monitoring of utterances, is a major factor that compromises sentence production in spoken discourse in latent aphasia.

SUPPLEMENTAL MATERIAL

https://doi.org/10.23641/asha.19448726.

Reliability and validity of the Stroke and Aphasia Quality of Life Scale-39 (SAQOL-39) for a Serbian population

Purpose: Aphasia has a negative impact on a person's quality of life (QOL). The Stroke Aphasia Quality of Life-39 scale (SAQOL-39) is a widely-used measure of health-related quality of life (HRQOL) developed for people with aphasia that has been translated into several languages. Its psychometric properties have been examined not only in English, but also in other languages. This study examined the reliability and validity of a translation and adaptation of the SAQOL-39 into Serbian in Serbian-speaking people with aphasia.Method: Using forward and backward translation, the SAQOL-39 was translated and adapted from English into Serbian and its psychometric properties were examined in 90 Serbian-speaking people with a broad range of times post-onset of aphasia. Internal consistency, test-retest reliability and other analyses were conducted.Result: Internal consistency and test-retest reliability of the Serbian version was high (Cronbach's α > 0.9; ICC ≥0.87), which is similar to versions of the scale in other languages.Conclusion: The Serbian translation and adaptation of the SAQOL-39 was shown to be a valid and reliable measure of QOL in people with aphasia with reliable psychometric properties and is suitable for the assessment of Serbian people with aphasia.

Demystifying the complexity of aphasia treatment: Application of the Rehabilitation Treatment Specification System (RTSS)

A considerable body of research supports the use of behavioral communication treatment as the standard of care for aphasia. In spite of robust progress in clinical aphasiology, many questions regarding optimal care remain unanswered. One of the major challenges to progress in the field is the lack of a common framework to adequately describe individual treatments, which, if available, would allow comparisons across studies as well as improved communication among researchers, clinicians, and other stakeholders. Here, we describe how aphasia treatment approaches can be systematically characterized using the Rehabilitation Treatment Specification System (RTSS). At the core of the RTSS is a tripartite structure that focuses on targets (the behavior that is expected to change as a result of treatment), ingredients (what a clinician does to affect change in the target), and mechanism(s) of action (why a given treatment works by linking the ingredients to the target). Three separate papers in the current issue specifically describe how the RTSS can be used to describe different kinds of aphasia treatment approaches: functional approaches, cognitive-linguistic approaches, and biological approaches. It is our hope that the application of the RTSS in clinical aphasiology will improve communication in published studies, grant proposals, and in the clinical care of persons with aphasia.

Combined molecular and mathematical analysis of long noncoding RNAs expression in fine needle aspiration biopsies as novel tool for early diagnosis of thyroid cancer

PURPOSE

In presence of indeterminate lesions by fine needle aspiration (FNA), thyroid cancer cannot always be easily diagnosed by conventional cytology. As a consequence, unnecessary removal of thyroid gland is performed in patients without cancer based on the lack of optimized diagnostic criteria. Aim of this study is identifying a molecular profile based on long noncoding RNAs (lncRNAs) expression capable to discriminate between benign and malignant nodules.

METHODS

Patients were subjected to surgery (n = 19) for cytologic suspicious thyroid nodules or to FNA biopsy (n = 135) for thyroid nodules suspicious at ultrasound. Three thyroid-specific genes (TG, TPO, and NIS), six cancer-associated lncRNAs (MALAT1, NEAT1, HOTAIR, H19, PVT1, MEG3), and two housekeeping genes (GAPDH and P0) were analyzed using Droplet Digital PCR (ddPCR).

RESULTS

Based on higher co-expression in malignant (n = 11) but not in benign (n = 8) nodules after surgery, MALAT1, PVT1 and HOTAIR were selected as putative cancer biomarkers to analyze 135 FNA samples. Cytological and histopathological data from a subset of FNA patients (n = 34) were used to define a predictive algorithm based on a Naïve Bayes classifier using co-expression of MALAT1, PVT1, HOTAIR, and cytological class. This classifier exhibited a significant separation capability between malignant and benign nodules (P < 0.0001) as well as both rule in and rule out test potential with an accuracy of 94.12% and a negative predictive value (NPV) of 100% and a positive predictive value (PPV) of 91.67%.

CONCLUSIONS

ddPCR analysis of selected lncRNAs in FNA biopsies appears a suitable molecular tool with the potential of improving diagnostic accuracy.

Sentence Recall in Latent and Anomic Aphasia: An Exploratory Study of Semantics and Syntax

We investigated whether semantic plausibility and syntactic complexity affect immediate sentence recall in people with latent and anomic aphasia. To date, these factors have not been explored in these types of aphasia. As with previous studies of sentence recall, we measured accuracy of verbatim recall and uniquely real-time speech measures. The results showed that accuracy did not distinguish performance between latent aphasia and neurotypical controls. However, some of the real-time speech measures distinguished performance between people with latent aphasia and neurotypical controls. There was some evidence, though not pervasive, that semantic plausibility and syntactic complexity influenced recall performance. There were no interactions between semantic plausibility and syntactic complexity. The speed of preparation of responses was slower in latent aphasia than controls; it was also slower in anomic aphasia than both latent and control groups. It appears that processing speed as indexed by temporal speech measures may be differentially compromised in latent and anomic aphasia. However, semantic plausibility and syntactic complexity did not show clear patterns of performance among the groups. Notwithstanding the absence of interactions, we advance an explanation based on conceptual short-term memory as to why semantically implausible sentences are typically more erroneous and possibly also slower in recall.

Temporal and Episodic Analyses of the Story of Cinderella in Latent Aphasia

Purpose The purpose of this study was to improve our understanding of the language characteristics of people with latent aphasia using measures that examined temporal (i.e., real-time) and episodic organization of discourse production. Method Thirty AphasiaBank participants were included (10 people with latent aphasia, 10 people with anomic aphasia, and 10 neurotypical control participants). Speech material of Cinderella narratives was analyzed with Praat software. We devised a protocol that coded the presence and duration of all speech segments, dysfluencies such as silent and filled pauses, and other speech behaviors. Using these durations, we generated a range of temporal measures such as speech, articulation, and pure word rates. Narratives were also coded into episodes, which provided information about the discourse macrostructure abilities of the participants. Results The latent aphasia group differed from controls in number of words produced, silent pause duration, and speech rate, but not articulation rate or pure word rate. Episodic organization of the narratives was similar in these 2 groups. The latent and anomic aphasia groups were similar in most measures, apart from articulation rate, which was lower in the anomic group. The anomic aphasia group also omitted more episodes than the latent aphasia group. Conclusions The differences between latent aphasia and neurotypical controls can be attributed to a processing speed deficit. We propose that this deficit results in an impaired ability to process information from multiple cognitive domains simultaneously.

Systematic review of subjective memory measures to inform assessing memory limitations after stroke and stroke-related aphasia

AIM

Primary aims of this systematic review were to: (1) identify the range of subjective memory measures used in the stroke and stroke-related aphasia literature and (2) critically appraise their psychometric properties as well as (3) the methodological qualities of studies that included them, (4) investigate whether such measures provide an accurate reflection of memory impairments (i.e., in comparison to norms from age-matched, neurotypical participants), (5) document the representation of individuals with stroke-related aphasia, and (6) examine the extent to which subjective memory measures correlate with objective memory measures.

METHODS

Systematic review of the literature from 1970 to June 2019 using a comprehensive range of relevant search terms in EMBASE, Medline, PsychINFO, SCOPUS, and Web of Science. Eligibility criteria were for studies to include adults who had suffered of clinical stroke, to report a subjective memory measure that was completed by the stroke survivors, to be reported in a peer-reviewed journal, and to be published in English or Dutch. Quality appraisal was carried out for the included studies as well as the subjective memory measures they employed.

RESULTS

A total of 7,077 titles or abstracts were screened, with 41 studies included in the quantitative and qualitative synthesis. Twenty-six subjective memory measures were used in the included studies. The critical appraisal of their psychometric properties and the methodological quality of the included studies revealed significant shortcomings; for example, neurotypical participants were included in only 14 of the 41 studies. When statistical comparisons were made, different outcomes arose. Only eight studies statistically compared subjective with objective memory measures.

CONCLUSIONS

This literature domain currently provides an unclear picture as to how memory limitations affect participation in stroke and stroke-related aphasia.IMPLICATIONS FOR REHABILITATIONA broad range of subjective memory measures have been used to determine stroke survivors' perceptions of their everyday memory issues.Because of psychometric weaknesses such as inadequate reliability and cross-cultural validity among subjective memory measures, there remains a need to carefully review a given measure's properties to determine if it is appropriate for use with a given stroke survivor.Stroke survivors with aphasia have been infrequently included or inadequately described in studies of subjective memory measures, and thus how these individuals perceive their everyday memory abilities requires further investigation.Although the relationship between subjective and objective memory measures has been infrequently investigated by stroke researchers, both types of measures should be considered as they likely offer complementary rather than redundant information about stroke survivors' memory abilities.

The Methodological Quality of Short-Term/Working Memory Treatments in Poststroke Aphasia: A Systematic Review

Purpose The aims of this systematic review are to provide a critical overview of short-term memory (STM) and working memory (WM) treatments in stroke aphasia and to systematically evaluate the internal and external validity of STM/WM treatments. Method A systematic search was conducted in February 2014 and then updated in December 2016 using 13 electronic databases. We provided descriptive characteristics of the included studies and assessed their methodological quality using the Risk of Bias in N-of-1 Trials quantitative scale ( Tate et al., 2015 ), which was completed by 2 independent raters. Results The systematic search and inclusion/exclusion procedure yielded 17 single-case or case-series studies with 37 participants for inclusion. Nine studies targeted auditory STM consisting of repetition and/or recognition tasks, whereas 8 targeted attention and WM, such as attention process training including n-back tasks with shapes and clock faces as well as mental math tasks. In terms of their methodological quality, quality scores on the Risk of Bias in N-of-1 Trials scale ranged from 4 to 17 ( M = 9.5) on a 0-30 scale, indicating a high risk of bias in the reviewed studies. Effects of treatment were most frequently assessed on STM, WM, and spoken language comprehension. Transfer effects on communication and memory in activities of daily living were tested in only 5 studies. Conclusions Methodological limitations of the reviewed studies make it difficult, at present, to draw firm conclusions about the effects of STM/WM treatments in poststroke aphasia. Further studies with more rigorous methodology and stronger experimental control are needed to determine the beneficial effects of this type of intervention. To understand the underlying mechanisms of STM/WM treatment effects and how they relate to language functioning, a careful choice of outcome measures and specific hypotheses about potential improvements on these measures are required. Future studies need to include outcome measures of memory functioning in everyday life and psychosocial functioning more generally to demonstrate the ecological validity of STM and WM treatments.

Equipping Nurses and Care Staff to Manage Mealtime Difficulties in People With Dementia: A Systematic Scoping Review of Training Needs and Interventions

Purpose Mealtime difficulties are prevalent in dementia, posing major challenges to people with dementia (PWD), carers, and clinical services. Speech-language pathologists have a recognized role in providing training to carers of PWD who have mealtime difficulties. The aims of this study are (a) to identify the training needs of nurses and care staff with regard to managing mealtime difficulties in PWD, (b) to describe existing training interventions on this topic, and (c) to investigate the extent to which these interventions are relevant to the needs of nurses and care staff. Method A systematic search was carried out to identify studies relevant to the aims of the review. Data were extracted and then synthesized using thematic analysis and a synthesis matrix. Study quality was appraised using a validated appraisal tool. Results Various themes were identified in relation to the training needs of nurses and other care staff who manage mealtime difficulties in PWD. These were as follows: person-centered care; dealing with uncertainty; strategies, skills, and knowledge; and creating the right environment. Existing training interventions were described and compared against the training needs. The review found some correspondence between interventions and staff needs, but also some gaps. Conclusions Training interventions on this topic should be more systematically developed and better reported to facilitate effective implementation. Evidence to date indicates that training should do more to help staff deal with uncertainty. Further research assessing the benefits of speech-language pathologists' involvement in the development of training interventions is recommended because of this profession's specialist skills and knowledge with regard to both dysphagia and communication.

The impact of aphasia on Internet and technology use

Purpose: This study compared Internet use post-stroke in people with aphasia (n = 25) and without aphasia (n = 17). The purpose was to understand how people with aphasia were using the Internet and to investigate the impact of aphasia on their use.Materials and methods: A face-to-face supported questionnaire explored the use of technologies, types of Internet use, traditional and Internet communication, the perception of abilities, and possible barriers to acquiring or improving Internet skills. Descriptive and inferential statistics were used to analyze the data.Results: Internet use ranged from fully independent to by proxy across both groups. Most participants perceived their aphasia as a barrier, but for the majority, it was not the sole reason for failing to acquire or improve skills. Aphasia was related to difficulties with technology-based written communication. Educational attainment was related to participant's feelings about their own skills. Whilst aphasia was important, analysis revealed that age was a stronger predictor of Internet use per se.Conclusions: It is clear that aphasia often negatively affects Internet use and proficiency. However, this research clearly demonstrates that it is important to consider the influence of factors such as age, proxy use, education, and previous technology use and experience.Implications for rehabilitationPost-stroke aphasia contributes negatively to Internet use, particularly in the use of online communication tools such as email and messaging services.Sub-groups of people with aphasia are likely to be more vulnerable to exclusion from the benefits of the Internet; specifically, older people and those with lower levels of educational attainment.It is common for both older adults with and without aphasia to use the Internet via a proxy. Independent use may not always be the desired goal within rehabilitation.People with aphasia may perceive their age and disability as barriers to using the Internet and may lack confidence in their own ability or potential.

Short-term memory span in aphasia: Insights from speech-timing measures

Auditory-verbal short-term memory impairments are part and parcel of aphasia and interfere with linguistic processing. To date, the science about short-term memory impairments in aphasia has been generated and dominated by studying measures of accuracy, that is, span length. Because accuracy is expressed through speech, examining the speech-timing characteristics of persons with aphasia as they engage in spoken recall could reveal insights about the manner in which accuracy is achieved. Six speech-timing measures (e.g., response durations, pause durations) were elicited from the speech waveform of word span tasks from twelve people with aphasia. Speech-timing measures were compared to neuro-typical control participants. Speech-timing performance between erroneous and correct responses in the aphasia group was also examined. Across all measures, people with aphasia produced considerably longer speech-timing patterns in comparison to control participants. Memory load affected some measures in people with aphasia and control participants. Speech-timing in correct response trials was shorter than responses in erroneous trials. Memory span correlated only with one measure, namely, speech time (defined as the sum of each individual word duration in a response). Speech time also correlated with the following measures: Aphasia severity (Aphasia Quotient of the Western Aphasia Battery), spontaneous speech, and language comprehension (also measured by the Western Aphasia Battery). Some protracted speech-timing patterns in the aphasia group may be explained by a deregulation of activation-decay patterns. However, in the absence of further evidence from people with aphasia, possible issues around the sensitivity of some speech-timing measures limit firmer conclusions. Speech-timing measures are response-time measures, which have not been systematically studied in studies of short-term or working memory in aphasia and as such, can push the current boundaries of knowledge of short-term and working memory impairments in aphasia, not only in stroke related aphasia but also other neurological conditions.

An International Survey of Assessment Practices for Short-Term and Working Memory Deficits in Aphasia

PURPOSE

Recent research has highlighted the clinical relevance of understanding the nature of short-term memory (STM) and working memory (WM) deficits in persons with aphasia and the way these deficits affect linguistic processing and functional communication in activities of daily living. The psychometric properties of tests commonly used to identify STM/WM problems in individuals with aphasia, however, have been questioned. No previous study has sought to investigate assessment practices and attitudes by speech-language pathologists involved in aphasia management. Accordingly, the aims of this study were (a) to investigate both attitudes toward STM/WM assessment in individuals with aphasia, as well as the types and frequency of STM/WM tests used with individuals with aphasia, and (b) to explore factors (e.g., educational background) that may influence STM/WM assessment practices.

METHOD

Respondents recruited via professional and aphasia support organizations completed an online survey. The survey elicited information about the respondents' demographic and clinical backgrounds and STM/WM assessment clinical practices and views, including frequency and preferred use of specific STM/WM tests.

RESULTS

The majority of respondents reported regular use of STM/WM tests as part of aphasia management. Positive attitudes toward STM/WM assessments were also reported. The most popular rankings of tests were the Cognitive Linguistic Quick Test (Helm-Estabrooks, 2001), the Comprehensive Aphasia Test (Swinburn, Porter, & Howard, 2005), and the Token Test (McNeil & Prescott, 1978). Results suggested limited knowledge about measures that assess self-perceptions of functional memory abilities. Regression analyses showed that the frequency of reported STM/WM test use was similar between clinicians and dual-role researchers/clinicians, but their attitudes toward the value of STM/WM differed. U.S. and UK respondents reported similar assessment practices.

CONCLUSIONS

It is reassuring that STM/WM is taken into consideration by clinicians when providing aphasia management. Two of the most popular tests, however, have poor psychometric properties, and caution should be exercised in clinical decision making. The different value placed on STM/WM testing by clinicians and researchers/clinicians has implications for continuing professional development.

Topological Filtering of Dynamic Functional Brain Networks Unfolds Informative Chronnectomics: A Novel Data-Driven Thresholding Scheme Based on Orthogonal Minimal Spanning Trees (OMSTs)

The human brain is a large-scale system of functionally connected brain regions. This system can be modeled as a network, or graph, by dividing the brain into a set of regions, or “nodes,” and quantifying the strength of the connections between nodes, or “edges,” as the temporal correlation in their patterns of activity. Network analysis, a part of graph theory, provides a set of summary statistics that can be used to describe complex brain networks in a meaningful way. The large-scale organization of the brain has features of complex networks that can be quantified using network measures from graph theory. The adaptation of both bivariate (mutual information) and multivariate (Granger causality) connectivity estimators to quantify the synchronization between multichannel recordings yields a fully connected, weighted, (a)symmetric functional connectivity graph (FCG), representing the associations among all brain areas. The aforementioned procedure leads to an extremely dense network of tens up to a few hundreds of weights. Therefore, this FCG must be filtered out so that the “true” connectivity pattern can emerge. Here, we compared a large number of well-known topological thresholding techniques with the novel proposed data-driven scheme based on orthogonal minimal spanning trees (OMSTs). OMSTs filter brain connectivity networks based on the optimization between the global efficiency of the network and the cost preserving its wiring. We demonstrated the proposed method in a large EEG database (N = 101 subjects) with eyes-open (EO) and eyes-closed (EC) tasks by adopting a time-varying approach with the main goal to extract features that can totally distinguish each subject from the rest of the set. Additionally, the reliability of the proposed scheme was estimated in a second case study of fMRI resting-state activity with multiple scans. Our results demonstrated clearly that the proposed thresholding scheme outperformed a large list of thresholding schemes based on the recognition accuracy of each subject compared to the rest of the cohort (EEG). Additionally, the reliability of the network metrics based on the fMRI static networks was improved based on the proposed topological filtering scheme. Overall, the proposed algorithm could be used across neuroimaging and multimodal studies as a common computationally efficient standardized tool for a great number of neuroscientists and physicists working on numerous of projects.

Short-Term and Working Memory Treatments for Improving Sentence Comprehension in Aphasia: A Review and a Replication Study

Although the roles of verbal short-term and working memory on spoken sentence comprehension skills in persons with aphasia have been debated for many years, the development of treatments to mitigate verbal short-term and working memory deficits as a way of improving spoken sentence comprehension is a new avenue in treatment research. In this article, we review and critically appraise this emerging evidence base. We also present new data from five persons with aphasia of a replication of a previously reported treatment that had resulted in some improvement of spoken sentence comprehension in a person with aphasia. The replicated treatment did not result in improvements in sentence comprehension. We forward recommendations for future research in this, admittedly weak at present, but important clinical research avenue that would help improve our understanding of the mechanisms of improvement of short-term and working memory training in relation to sentence comprehension.

The use of standardised short-term and working memory tests in aphasia research: a systematic review

Impairments of short-term and working memory (STM, WM), both verbal and non-verbal, are ubiquitous in aphasia. Increasing interest in assessing STM and WM in aphasia research and clinical practice as well as a growing evidence base of STM/WM treatments for aphasia warrant an understanding of the range of standardised STM/WM measures that have been utilised in aphasia. To date, however, no previous systematic review has focused on aphasia. Accordingly, the goals of this systematic review were: (1) to identify standardised tests of STM and WM utilised in the aphasia literature, (2) to evaluate critically the psychometric strength of these tests, and (3) to appraise critically the quality of the investigations utilising these tests. Results revealed that a very limited number of standardised tests, in the verbal and non-verbal domains, had robust psychometric properties. Standardisation samples to elicit normative data were often small, and most measures exhibited poor validity and reliability properties. Studies using these tests inconsistently documented demographic and aphasia variables essential to interpreting STM/WM test outcomes. In light of these findings, recommendations are provided to foster, in the future, consistency across aphasia studies and confidence in STM/WM tests as assessment and treatment outcome measures.

Assessment and treatment of short-term and working memory impairments in stroke aphasia: a practical tutorial

BACKGROUND

Aphasia following stroke refers to impairments that affect the comprehension and expression of spoken and/or written language, and co-occurring cognitive deficits are common. In this paper we focus on short-term and working memory impairments that impact on the ability to retain and manipulate auditory-verbal information. Evidence from diverse paradigms (large group studies, case studies) report close links between short-term/working memory and language functioning in aphasia. This evidence leads to the hypothesis that treating such memory impairments would improve language functioning. This link has only recently been acknowledged in aphasia treatment but has not been embraced widely by clinicians.

AIMS

To examine the association between language, and short-term and working memory impairments in aphasia. To describe practical ways of assessing short-term and working memory functioning that could be used in clinical practice. To discuss and critically appraise treatments of short-term and working memory reported in the literature.

METHODS & PROCEDURES

Taking a translational research approach, this paper provides clinicians with current evidence from the literature and practical information on how to assess and treat short-term and working memory impairments in people with aphasia. Published treatments of short-term and/or working memory in post-stroke aphasia are discussed through a narrative review.

MAIN CONTRIBUTIONS

This paper provides the following. A theoretical rationale for adopting short-term and working memory treatments in aphasia. It highlights issues in differentially diagnosing between short-term, working memory disorders and other concomitant impairments, e.g. apraxia of speech. It describes short-term and working memory assessments with practical considerations for use with people with aphasia. It also offers a description of published treatments in terms of participants, treatments and outcomes. Finally, it critically appraises the current evidence base relating to the treatment of short-term and working memory treatments.

CONCLUSIONS

The links between short-term/working memory functioning and language in aphasia are generally acknowledged. These strongly indicate the need to incorporate assessment of short-term/working memory functioning for people with aphasia. While the supportive evidence for treatment is growing and appears to highlight the benefits of including short-term/working memory in aphasia treatment, the quality of the evidence in its current state is poor. However, because of the clinical needs of people with aphasia and the prevalence of short-term/working memory impairments, incorporating related treatments through practice-based evidence is advocated.

Iron and holotransferrin induce cAMP-dependent differentiation of Schwann cells

The differentiation of myelin-forming Schwann cells (SC) is completed with the appearance of myelin proteins MBP and P(0) and a concomitant downregulation of markers GFAP and p75NTR, which are expressed by immature and adult non-myelin-forming SC. We have previously demonstrated that holotransferrin (hTf) can prevent SC dedifferentiation in culture (Salis et al., 2002), while apotransferrin (aTf) cannot. As a consequence, we used pure cultured SC and submitted them to serum deprivation in order to promote dedifferentiation and evaluate the prodifferentiating ability of ferric ammonium citrate (FAC) through the expression of MBP, P(0), p75NTR and c-myc. The levels of cAMP, CREB and p-CREB were also measured. Results show that Fe(3+), either in its free form or as hTf, can prevent the dedifferentiation promoted by serum withdrawal. Both FAC and hTf were proven to promote differentiation, probably through the increase in cAMP levels and CREB phosphorylation, as well as levels of reactive oxygen species. This effect was inhibited by deferroxamine (Dfx, an iron chelator), H9 (a cAMP-PKA antagonist) and N-acetylcysteine (NAC, a powerful antioxidant).

Processing of wh-questions in a case of posterior cortical atrophy

Posterior cortical atrophy (PCA) is a type of dementia that is characterized by visuo-spatial and memory deficits, dyslexia and dysgraphia, relatively early onset and preserved insight. Language deficits have been reported in some cases of PCA. Using an off-line grammaticality judgement task, processing of wh-questions is investigated in a case of PCA. Other aspects of auditory language are also reported. It is shown that processing of wh-questions is influenced by syntactic structure, a novel finding in this condition. The results are discussed with reference to accounts of wh-questions in aphasia. An uneven profile of other language abilities is reported with deficits in digit span (forward, backward), story retelling ability, comparative questions but intact abilities in following commands, repetition, concept definition, generative naming and discourse comprehension.

The mRNA of transferrin is expressed in Schwann cells during their maturation and after nerve injury

Transferrin, the iron carrier protein, has been shown to be involved in oligodendroglial cell differentiation in the central nervous system but little is known about its role in the peripheral nervous system. In the present work, we have studied the presence of transferrin and of its mRNA in rat sciatic nerves and in Schwann cells isolated at embryonic and adult ages as well as during the regeneration process that follows nerve crush. We have also studied the correlation between the expression of the mRNAs of transferrin and the expression of mature myelin markers in the PNS. We show that transferrin is present in whole sciatic nerves at late stages of embryonic life as well as at postnatal day 4 and in adult rats. We demonstrate for the first time, that in normal conditions, the transferrin mRNA is expressed in Schwann cells isolated from sciatic nerves between embryonic days 14 and 18, being absent at later stages of development and in adult animals. In adult rats, 3 days after sciatic nerve crushing, the mRNA of transferrin is expressed in the injured nerve, but 7 days after injury its expression disappears. Transferrin protein in the sciatic nerve closely follows the expression of its mRNA indicating that under these circumstances, it appears to be locally synthesized. Transferrin in the PNS could have a dual role. During late embryonic ages it could be locally synthesized by differentiating Schwann cells, acting as a pro-differentiating factor. A similar situation would occur during the regeneration that follows Wallerian degeneration. In the adult animals on the other hand, Schwann cells could pick up transferrin from the circulation or/and from the axons, sub serving possible trophic actions closely related to myelin maintenance.

Presence of alpha-globin mRNA and migration of bone marrow cells after sciatic nerve injury suggests their participation in the degeneration/regeneration process

We have previously reported that in the distal stump of ligated sciatic nerves, there is a change in the distribution of myelin basic protein (MBP) and P0 protein immunoreactivities. These results agreed with the studies of myelin isolated from the distal stump of animals submitted to ligation of the sciatic nerve, showing a gradual increase in a 14 kDa band with an electrophoretic mobility similar to that of an MBP isoform, among other changes. This band, which was resolved into two bands of 14 and 15 kDa using a 16% gel, was found to contain a mixture of MBP fragments and peptides with great homology with alpha- and beta-globins. In agreement with these results, we have demonstrated that the mRNA of alpha-globin is present in the proximal and distal stumps of the ligated nerve. It is also detected at very low levels in Schwann cells isolated from normal nerves. These results could be due to the presence of alpha- and/or beta-globin arising from immature cells of the erythroid series. Also, they could be present in macrophages, which spontaneously migrate to the injured nerve to promote the degradation of myelin proteins. Cells isolated from normal adult rat bone marrow which were injected intraortically were found to migrate to the injured area. These cells could contribute to the remyelination of the damaged area participating in the removal of myelin debris, through their transdifferentiation into Schwann cells or through their fusion with preexisting Schwann cells in the distal stump of the injured sciatic nerve.

HoloTransferrin but not ApoTransferrin prevents Schwann cell de-differentiation in culture

Schwann cells (SCs) in culture, without the presence of axons, become de-differentiated, reaching a condition similar to that of their precursor cells. The cytoplasmic accumulation of transferrin (Tf) in the myelinated peripheral nerve has been reported and data in the literature support a role for apoTf in myelination in the CNS. In the present report, we used SC cultures to evaluate the capacity of apoTf and holoTf to prevent cell de-differentiation promoted by fetal calf serum deprivation. SCs incubated in a serum-free medium showed a decrease in the expression of myelin basic protein (MBP) and P(0), markers of mature myelin-forming SCs, together with an increase in the levels of p75NTR and glial fibrillary acidic protein, markers of immature SCs. Treatment with holoTf prevented the decrease in expression of MBP and P(0) and the increase in p75NTR. ApoTf was unable to prevent these changes except when iron was added to the cultures. These results suggest a role for holoTf in the regulation of myelin formation by SCs.

Early postoperative enteral nutrition improves gut oxygenation and reduces costs compared with total parenteral nutrition

OBJECTIVE

To evaluate the potential clinical, metabolic, and economic advantages of enteral nutrition over total parenteral nutrition.

DESIGN

Prospective, randomized clinical trial.

SETTING

Department of surgery in a university hospital.

PATIENTS

Two hundred and fifty-seven patients with cancer of the stomach (n = 121), pancreas (n = 110), or esophagus (n = 26) were randomized to receive postoperative total parenteral nutrition (TPN group, n = 131) or early enteral nutrition (EEN group, n = 126). The nutritional goal was 25 kcal/kg/day. The two nutritional formulas were isocaloric and isonitrogenous, and they were continued until oral intake was at least 800 kcal/day.

MEASUREMENTS

Morbidity, mortality, length of hospital stay, and treatment costs were evaluated in all patients. In 40 consecutive patients, selected nutritional, immunologic and inflammatory variables were studied. Moreover, intestinal oxygen tension was evaluated by micropolarographic implantable probes.

MAIN RESULTS

The nutritional goal was reached in 100/126 (79.3%) patients in the EEN group and in 128/131 (97.7%) patients in the TPN group (p <.001). In the EEN group, hyperglycemia (serum glucose, >200 mg/dL) was observed in 4.7% of the patients vs. 9.1% in the TPN group (p = NS). Alteration of serum electrolyte levels was 3.9% in the EEN group vs. 13.7% in the TPN group (p <.01). No significant difference was found in nutritional, immunologic, and inflammatory variables between the two groups. The overall complication rate was similar (40.4% for TPN vs. 35.7%, for EEN; p =.52). No difference was detected for either infectious or noninfectious complications, length of hospital stay, and mortality. From postoperative day 5, intestinal oxygen tension recovered faster in the EEN group than in the TPN group (43 +/- 5 mm Hg vs. 31 +/- 4 mm Hg at day 7; p <.001). EEN was four-fold less expensive than TPN ($25 vs. $90.60/day, respectively).

CONCLUSION

EEN represents a rational alternative to TPN in patients who undergo upper gastrointestinal tract surgery for cancer and who clinically require postoperative artificial nutrition.