Language impairment in dementia of the Alzheimer type: a hierarchical decline?

Language and Communication Interventions in People with Alzheimer's Disease: A Systematic Review

Although language impairment is frequently observed in patients with Alzheimer's disease (pwAD), targeted language rehabilitation is often overlooked. The present study reviews published evidence on the impact of language training, either alone or in combination with cognitive training, on cognitive outcomes in pwAD. A systematic search of PubMed, Google Scholar, and Cochrane was carried out, including studies published from inception to November 2023. A total of eight research articles (four randomized controlled trials and four observational studies) met the inclusion criteria: six assessed language training combined with cognitive training and two evaluated language rehabilitation alone. Regarding language and non-language (mainly memory, attention, and executive functions) outcomes, there was a consensus among studies that language rehabilitation (alone or in combination with cognitive training) yields positive results. Some of the articles also explored the impact on patients' and their caregivers' quality of life, with all but one showing improvement. Consequently, the combination of language and cognitive training leads to improvements across various cognitive domains. However, limited evidence supports the value of sole language rehabilitation. This conclusion is influenced by heterogeneity among studies (different types and duration of interventions, small participant sets, various assessment tools), and, thus, further research is warranted.

Coordinating Words and Sentences: Detecting Age-Related Changes in Language Production

PURPOSE

The purpose of this study was to examine whether older adults exhibit reduced abilities in coordinating lexical retrieval and syntactic formulation during sentence production and whether an individual's working memory capacity predicts age-related changes in sentence production.

METHOD

A total of 124 Korean-speaking individuals (79 young and 45 older adults) completed a lexical priming sentence production task. The participants described a target picture (a dog biting a monkey) after reading either an agent (dog) or a theme (monkey) prime word. The proportion of passive sentences was used as the dependent variable.

RESULTS

When the theme noun was primed, older adults produced fewer passive sentences than young adults. Working memory tasks significantly predicted individual differences in the sentence production of older adults.

CONCLUSIONS

With aging, the ability to efficiently formulate syntactic structures in coordination with varying lexical information declines. Among older adults, age-related changes in these sentence production processes are associated with reduced working memory. Our constrained language production task is sensitive to detecting aging effects.

Atypical instantaneous spatio-temporal patterns of neural dynamics in Alzheimer's disease

Cognitive functions produced by large-scale neural integrations are the most representative 'emergence phenomena' in complex systems. A novel approach focusing on the instantaneous phase difference of brain oscillations across brain regions has succeeded in detecting moment-to-moment dynamic functional connectivity. However, it is restricted to pairwise observations of two brain regions, contrary to large-scale spatial neural integration in the whole-brain. In this study, we introduce a microstate analysis to capture whole-brain instantaneous phase distributions instead of pairwise differences. Upon applying this method to electroencephalography signals of Alzheimer's disease (AD), which is characterised by progressive cognitive decline, the AD-specific state transition among the four states defined as the leading phase location due to the loss of brain regional interactions could be promptly characterised. In conclusion, our synthetic analysis approach, focusing on the microstate and instantaneous phase, enables the capture of the instantaneous spatiotemporal neural dynamics of brain activity and characterises its pathological conditions.

Intraindividual variability measured with dispersion across diagnostic groups in a memory clinic sample

Increased intraindividual variability (IIV) has been linked to outcomes such as cognitive decline and dementia, suggesting IIV might add valuable diagnostic information beyond traditional neuropsychological interpretation. We explored whether a subtype of IIV, dispersion, can provide additional information for dementia diagnosis. In a sample of memory clinic patients, three cognitive status groups were identified: subjective cognitive impairment (SCI; n = 85), amnestic mild cognitive impairment (a-MCI; n = 16), and dementia due to Alzheimer's disease (AD; n = 48). Dispersion was computed as intraindividual standard deviations across multiple neuropsychological measures within three cognitive domains (executive functioning; immediate and delayed memory) and was compared for each diagnostic group using profile analysis. Patients with AD and a-MCI demonstrated less dispersion than patients with SCI in delayed memory. Results support existing theoretic perspectives on cognitive variability and age-related cognitive decline but suggest floor effects underlie suppression of dispersion in amnestic cognitive presentations. Questions remain about the contribution of IIV beyond impressions of impairment versus no impairment in these constrained representations of cognitive domains. Future investigations should investigate variability in SCI groups against controls to examine whether observed dispersion similarities between SCI and a-MCI or AD in immediate memory and executive functioning are meaningful.

The efficacy of memory load on speech-based detection of Alzheimer's disease

Introduction

The study aims to test whether an increase in memory load could improve the efficacy in detection of Alzheimer's disease and prediction of the Mini-Mental State Examination (MMSE) score.

Methods

Speech from 45 mild-to-moderate Alzheimer's disease patients and 44 healthy older adults were collected using three speech tasks with varying memory loads. We investigated and compared speech characteristics of Alzheimer's disease across speech tasks to examine the effect of memory load on speech characteristics. Finally, we built Alzheimer's disease classification models and MMSE prediction models to assess the diagnostic value of speech tasks.

Results

The speech characteristics of Alzheimer's disease in pitch, loudness, and speech rate were observed and the high-memory-load task intensified such characteristics. The high-memory-load task outperformed in AD classification with an accuracy of 81.4% and MMSE prediction with a mean absolute error of 4.62.

Discussion

The high-memory-load recall task is an effective method for speech-based Alzheimer's disease detection.

Breaking the flow of thought: Increase of empty pauses in the connected speech of people with mild and moderate Alzheimer's disease

INTRODUCTION

The profile of spontaneous speech in Alzheimer's disease (AD) includes increased pausing as a window into cognitive decline. We here aimed to further characterize the pausing profile of AD by linking pauses to the syntactic positions in which they appear and disease progression.

METHODS

Speech was obtained through a picture description task, thus minimizing demands on episodic memory (EM), from a group of mild (N = 21) and moderate AD (N = 19), and healthy elderly controls (N = 40). Pauses were sub-indexed according to whether they occurred within-clauses, clause-initially, or utterance-initially, and whether they preceded nouns, verbs, or adjectives/adverbs, when occurring within-clauses. Additionally, relations to verbal fluency (VF) measures at the single-word level were explored.

RESULTS

Pause rate but not duration distinguished controls from both AD groups, while fillers did not distinguish any groups. The analysis by syntactic position revealed a highly differentiated picture, with largest effect sizes of significant group differences seen in the utterance-initial pause rate. The two AD groups patterned differently when compared to controls, while none of the measures differentiated the AD groups. Specifically, moderate but not mild AD differed from controls in clause-initial pauses, while mild but not moderate AD differed from controls in within-clause positions. At the within-clause level, the effect dividing controls from mild-AD was specifically driven by pauses ahead of nouns. A significant negative correlation emerged between pausing rate in spontaneous speech and VF measures in the mild-AD group only.

CONCLUSIONS

Increased empty (non-filled) pauses in AD are not confined to pauses in within-clause positions, which are most directly related to problems in the retrieval of words. Even in early disease stages, where these within-clause pause effects are seen, they are confined to nouns, revealing a grammatically specific problem possibly related to the referencing of objects. At all disease stages, pauses increase in utterance-sized units of structure, indicating progressive problems in the creative configuration of complete thoughts.

The Diagnostic Value of Language Screening in Primary Progressive Aphasia: Validation and Application of the Sydney Language Battery

PURPOSE

The three variants of primary progressive aphasia (PPA) differ in clinical presentation, underlying brain pathology, and clinical course, which stresses the need for early differentiation. However, brief cognitive tests that validly distinguish between all PPA variants are lacking. The Sydney Language Battery (SYDBAT) is a promising screening instrument that can be used as a first step in a comprehensive neuropsychological assessment to distinguish PPA subtypes, but evidence on its validity and reliability is to date limited. In the current study, the validation and diagnostic value of the SYDBAT are described for discriminating PPA subtypes as well as distinguishing PPA from mild cognitive impairment (MCI) or Alzheimer's dementia (AD).

METHOD

Forty-five patients with PPA (13 with semantic PPA, 20 with logopenic PPA, and 12 with nonfluent/agrammatic PPA), 25 MCI patients, 13 AD patients, and 50 cognitively unimpaired controls were included in this study. Both patients and controls completed the SYDBAT-NL (Dutch version). Performance on and predictive ability of the four subtests (i.e., Naming, Word Comprehension, Repetition, and Semantic Association) were assessed. In addition, construct validity and internal consistency were examined.

RESULTS

Different SYDBAT performance patterns were found across PPA and non-PPA patient groups. While a discriminant function analysis based on SYDBAT subtest scores could predict PPA subtype with 78% accuracy, it was more difficult to disentangle PPA from non-PPA patients based on SYDBAT scores alone. For assisting in clinical interpretation, simple rules were set up and translated into a diagnostic decision tree for subtyping PPA, which was capable of diagnosing a large proportion of the cases. Satisfying validity and reliability measures were found.

CONCLUSIONS

The SYDBAT is an easy-to-use and promising screen for assessing single-word language processes, which may contribute to the differential diagnostic process of PPA and the assessment of language impairment in MCI and AD. It can be easily implemented for initial screening of patients in a memory clinic.

Language changes in Alzheimer's disease: A systematic review of verb processing

Alzheimer's disease (AD) results in language impairments and higher-level communication problems. Research into the language of people with AD (pwAD) has mainly focused on nouns; however, improved understanding of verb processing by pwAD could improve diagnostic assessments and communicative interventions. This systematic review synthesizes findings of AD's effects on verbs from single-word, sentence, and discourse tasks. Review of 57 studies revealed that pwAD were less accurate than controls on single-word tasks and less accurate with verbs than nouns on these tasks. They had difficulty comprehending sentences featuring multiple verbs or verbs with reversible thematic roles. Discourse production by pwAD was marked by vagueness, including declines in total output and propositional content and a preference for generic verbs and simple syntax. Few studies examining sentence production or discourse comprehension were found. Future research should address relationships between long-term memory and language preservation as well as verb use in discourse.

Language Decline Characterizes Amnestic Mild Cognitive Impairment Independent of Cognitive Decline

Purpose This research investigated the nature of cognitive decline in prodromal Alzheimer's disease (AD), particularly in mild cognitive impairment, amnestic type (aMCI). We assessed language in aMCI as compared with healthy aging (HA) and healthy young (HY) with new psycholinguistic assessment of complex sentences, and we tested the degree to which deficits on this language measure relate to performance in other general cognitive domains such as memory. Method Sixty-one individuals with aMCI were compared with 24 HA and 10 HY adults on a psycholinguistic measure of complex sentence production (relative clauses). In addition, HA, HY, and a subset of the aMCI participants (n = 22) were also tested on a multidomain cognitive screen, the Addenbrooke's Cognitive Examination-Revised (ACE-R), and on a verbal working memory Brown-Peterson (BP) test. General and generalized linear mixed models were used to test psycholinguistic results and to test whether ACE-R and BP performance predicted performance on the psycholinguistic test similarly in the aMCI and HA groups. Results On the psycholinguistic measure, sentence imitation was significantly deficited in aMCI in comparison with that in HA and HY. Experimental factorial designs revealed that individuals with aMCI had particular difficulty repeating sentences that especially challenged syntax-semantics integration. As expected, the aMCI group also performed significantly below the HY and HA groups on the ACE-R. Neither the ACE-R Memory subtest nor the BP total scores predicted performance on the psycholinguistic task for either the aMCI or the HA group. However, the ACE-R total score significantly predicted psycholinguistic task performance, with increased ACE-R performance predicting increased psycholinguistic task performance only for the HA group, not for the aMCI group. Conclusions Results suggest a selective deterioration in language in aMCI, specifically a weakening of syntax-semantics integration in complex sentence processing, and a general independence of this language deficit and memory decline. Results cohere with previous assessments of the nature of difficulty in complex sentence formation in aMCI. We argue that clinical screening for prodromal AD can be strengthened by supplementary testing of language, as well as memory, and extended evaluation of strength of their relation.

Textual Inference Comprehension in Mild Cognitive Impairment: The Influence of Semantic Processing and Verbal Episodic Memory

Language complaints, especially in complex tasks, may occur in mild cognitive impairment (MCI). Various language measures have been studied as cognitive predictors of MCI conversion to Alzheimer's type dementia. Understanding textual inferences is considered a high-demanding task that recruits multiple cognitive functions and, therefore, could be sensitive to detect decline in the early stages of MCI. Thus, we aimed to compare the performance of subjects with MCI to healthy elderly in a textual inference comprehension task and to determine the best predictors of performance in this ability considering one verbal episodic memory and two semantic tasks. We studied 99 individuals divided into three groups: (1) 23 individuals with amnestic mild cognitive impairment (aMCI), (2) 42 individuals with non-amnestic mild cognitive impairment (naMCI), (3), and (4) 34 cognitively healthy individuals for the control group (CG). A reduced version of The Implicit Management Test was used to assess different types of inferential reasoning in text reading. MCI patients performed poorer than healthy elderly, and there were no differences between MCI subgroups (amnestic and non-amnestic). The best predictors for inference-making were verbal memory in the aMCI and semantic tasks in the naMCI group. The results confirmed that the failure to understand textual inferences can be present in MCI and showed that different cognitive skills like semantic knowledge and verbal episodic memory are necessary for inference-making.

Individuals With Mild Cognitive Impairment and Alzheimer's Disease Benefit From Audiovisual Speech Cues and Supportive Sentence Context

Purpose Speech perception in noise becomes difficult with age but can be facilitated by audiovisual (AV) speech cues and sentence context in healthy older adults. However, individuals with Alzheimer's disease (AD) may present with deficits in AV integration, potentially limiting the extent to which they can benefit from AV cues. This study investigated the benefit of these cues in individuals with mild cognitive impairment (MCI), individuals with AD, and healthy older adult controls. Method This study compared auditory-only and AV speech perception of sentences presented in noise. These sentences had one of two levels of context: high (e.g., "Stir your coffee with a spoon") and low (e.g., "Bob didn't think about the spoon"). Fourteen older controls (M _age = 72.71 years, SD = 9.39), 13 individuals with MCI (M _age = 79.92 years, SD = 5.52), and nine individuals with probable Alzheimer's-type dementia (M _age = 79.38 years, SD = 3.40) completed the speech perception task and were asked to repeat the terminal word of each sentence. Results All three groups benefited (i.e., identified more terminal words) from AV and sentence context. Individuals with MCI showed a smaller AV benefit compared to controls in low-context conditions, suggesting difficulties with AV integration. Individuals with AD showed a smaller benefit in high-context conditions compared to controls, indicating difficulties with AV integration and context use in AD. Conclusions Individuals with MCI and individuals with AD do benefit from AV speech and semantic context during speech perception in noise (albeit to a lower extent than healthy older adults). This suggests that engaging in face-to-face communication and providing ample context will likely foster more effective communication between patients and caregivers, professionals, and loved ones.

Can discourse processing performance serve as an early marker of Alzheimer’s disease and mild cognitive impairment? A systematic review of text comprehension

A number of linguistic and cognitive deficits have been reported during the course of Alzheimer’s disease (AD) and its preceding stage of mild cognitive impairment (MCI), with some deficits appearing years before onset of clinical symptoms. It continues to be a critical task to identify tools that may serve as an early marker of pathology that are also reliably able to distinguish AD from normal ageing. Given the limited success of classic psychometric cognitive testing, a novel approach in assessment is warranted. A potentially sensitive assessment paradigm is discourse processing. The aim of this review was to synthesize original research studies investigating comprehension of discourse in AD and MCI, and to evaluate the potential of this paradigm as a promising avenue for further research. A literature search targeting studies with AD or MCI groups over 60 years of age was conducted in PubMed, Web of Science, and PsycINFO databases. Eight articles with good quality were included in the review. Six measures of discourse comprehension—naming latency, summary, lesson, main idea, proportion of inferential clauses, true/false questions—were identified. All eight studies reported significant deficits in discourse comprehension in AD and MCI groups on five of the six measures, when compared to cognitively healthy older adults. Mixed results were observed for associations with commonly used cognitive measures. Given the consistent findings for discourse comprehension measures across all studies, we strongly recommend further research on its early predictive potential, and discuss different avenues for research.

Meta-Analysis on the Effectiveness of Virtual Reality Cognitive Training (VRCT) and Computer-Based Cognitive Training (CBCT) for Individuals with Mild Cognitive Impairment (MCI)

This meta-analysis aims to assess the effectiveness of virtual reality cognitive training (VRCT) and conventional computer-based cognitive training (CBCT) in five specific cognitive domains (i.e., global cognitive function (GCF), memory (Mem), executive function (EF), language (Lang) and visuospatial skills (VS)) of individuals with mild cognitive impairment. A total of 320 studies were yielded from five electronic databases. Eighteen randomized controlled trials met the PRISMA criteria, with 10 related to VRCT and 8 related to CBCT. A random-effect model was used in determining the main effect of cognitive training in five specific cognitive domains. VRCT provided the largest effect size on VS and Lang while the smallest on EF. CBCT provided the largest effect size on Mem and Lang while the smallest on EF. VRCT and CBCT generate an opposite effect on VS. VRCT outweighs CBCT in treatment effectiveness of GCF, EF, Lang and VS. More immersive and interactive experiences in VRCT may help individuals with MCI better engage in real-life experiences, which supports skill generalization and reduces external distractions. CBCT tends to improve Mem but no definite conclusions can be made. Further investigation with more stringent research design and specific protocol are required to reach consensus about the optimum intervention regime.

Modelling the information seeking and searching behaviour of users with impairments: are existing models applicable?

Purpose

A substantial number of models have been developed over the years, with the purpose of describing the information seeking and searching of people in various user groups and contexts. Several models have been frequently applied in user studies, but are rarely included in research on participants with impairments. Models are purposeful when developing theories. Consequently, it might be valuable to apply models when studying this user group, as well. The purpose of this study was to explore whether existing models are applicable in describing the online information seeking and searching of users with impairments, with an overall aim to increase the use of models in studies involving impairments.

Design/methodology/approach

Six models were selected according to the following criteria: the model should address information seeking or searching, include the interaction between users and systems whilst incorporating assistive technology. Two user groups were selected from each of the categories: cognitive, sensory and motor impairments, namely dyslexia, autism, blindness, deafness, paralysation and Parkinson's. The models were then analysed based on known barriers reported for these cohorts.

Findings

All the selected models had potential to be applied in user studies involving impairments. While three of the models had the highest potential to be used in the current form, the other three models were applicable either through minor revisions or by combining models.

Originality/value

This study contributes with a new perspective on the use of models in information seeking and searching research on users with impairments.

Detecting Alzheimer's Disease from Continuous Speech Using Language Models

BACKGROUND

Recently, many studies have been carried out to detect Alzheimer's disease (AD) from continuous speech by linguistic analysis and modeling. However, few of them utilize language models (LMs) to extract linguistic features and to investigate the lexical-level differences between AD and healthy speech.

OBJECTIVE

Our goals include obtaining state-of-art performance of automatic AD detection, emphasizing N-gram LMs as powerful tools for distinguishing AD patients' narratives from those of healthy controls, and discovering the differences of lexical usages between AD patients and healthy people.

METHOD

We utilize a subset of the DementiaBank corpus, including 242 control samples from 99 control participants and 256 AD samples from 169 "PossibleAD" or "ProbableAD" participants. Baseline models are built through area under curve-based feature selection and using five machine learning algorithms for comparison. Perplexity features are extracted using LMs to build enhanced detection models. Finally, the differences of lexical usages between AD patients and healthy people are investigated by a proportion test based on unigram probabilities.

RESULTS

Our baseline model obtains a detection accuracy of 80.7%. This accuracy increases to 85.4% after integrating the perplexity features derived from LMs. Further investigations show that AD patients tend to use more general, less informative, and less accurate words to describe characters and actions than healthy controls.

CONCLUSION

The perplexity features extracted by LMs can benefit the automatic AD detection from continuous speech. There exist lexical-level differences between AD and healthy speech that can be captured by statistical N-gram LMs.

Using narratives in differential diagnosis of neurodegenerative syndromes

PURPOSE

Language decline has been associated with healthy aging and with various neurodegenerative conditions, making it challenging to differentiate among these conditions. This study examined the utility of linguistic measures derived from a short narrative language sample for 1) identifying language characteristics and cut-off scores to differentiate between healthy aging, Primary Progressive Aphasia (PPA), Mild Cognitive Impairment (MCI), and Alzheimer's dementia (AD); and 2) differentiating among PPA variants in which language is the primary impairment.

METHOD

Participants were 25 neurologically healthy English speakers, 20 individuals with MCI, 20 with AD, and 26 with PPA (non-fluent/agrammatic N = 10, logopenic N = 9, semantic N = 7). Narrative language samples of the Cookie Theft Picture of persons with healthy aging, MCI and AD were retrospectively obtained from the DementiaBank database (https://talkbank.org/DementiaBank/) and PPA samples were obtained from an ongoing research study. The language samples were analyzed for fluency, word retrieval success, grammatical accuracy, and errors using automated and manual analysis methods. The sensitivity and specificity of various language measures was computed.

RESULTS

Participants with PPA scored lower than neurologically healthy and MCI groups on fluency (words per minute and disfluencies), word retrieval (Correct Information Units and number of errors), and sentence grammaticality. PPA and AD groups did not differ on language measures. Agrammatic PPA participants scored lower than logopenic and semantic PPA groups on several measures, while logopenic and semantic PPA did not differ on any measures.

CONCLUSION

Measures derived from brief language samples and analyzed using mostly automated methods are clinically useful in differentiating PPA from healthy aging and MCI, and agrammatic PPA from other variants. The sensitivity and specificity of these measures is modest and can be improved when coupled with clinical presentation.

Emotional Expression of Persons with Dementia: An Integrative Review with Implications for Evidence-Based Practice

BACKGROUND

The ability to express emotion typically is preserved longer than language and cognitive function in persons living with dementia. Emotional expression may be an important indicator of underlying individual needs and feelings and may therefore facilitate person-centered care.

AIMS

This review aimed to examine how emotional expression has been described, measured, and utilized in empirical studies.

METHODS

The design of this study was an integrative literature review. A systematic search was conducted through electronic databases using defined search terms. Articles published up to March 2018 were included. The method proposed by Whittemore and Knafl was used for data synthesis and review integration. Quality appraisal of the selected articles was evaluated by the Mixed Methods Assessment Tool.

RESULTS

Most of the articles used feeling-related terms without specific definitions. Less frequently, terms such as affect, emotion, and mood were defined. Although these terms were used interchangeably in the articles, affect, which was defined as expressed emotion in general, was a comprehensive term to encompass other terms. Measurement of emotional expression was performed using observational methods, with direct observation or video recording using a hand-held camera. In both cases, observed emotion was coded with diverse methods or tools. In studies, the emotional expression was utilized as (a) an outcome to demonstrate the effect of interventions, (b) a factor to show relationship with other variables, or (c) an observed value itself.

LINKING EVIDENCE TO ACTION

This review provides insights about measurement options for emotional expressions among persons with dementia in long-term care. Long-term care staff should pay attention to emotional expression of persons with dementia to understand underlying unmet needs. Development of adequate measurement of emotional expression could facilitate development of emotion-oriented intervention program to improve psychological well-being and the behavioral and functional health of persons living with dementia.

High amyloid burden is associated with fewer specific words during spontaneous speech in individuals with subjective cognitive decline

Self-perceived word-finding difficulties are common in aging individuals as well as in Alzheimer's Disease (AD). Language and speech deficits are difficult to objectify with neuropsychological assessments. We therefore aimed to investigate whether amyloid, an early AD pathological hallmark, is associated with speech-derived semantic complexity. We included 63 individuals with subjective cognitive decline (age 64 ± 8, MMSE 29 ± 1), with amyloid status (positron emission tomography [PET] scans n = 59, or Aβ_1-42 cerebrospinal fluid [CSF] n = 4). Spontaneous speech was recorded using three open-ended tasks (description of cookie theft picture, abstract painting and a regular Sunday), transcribed verbatim and subsequently, linguistic parameters were extracted using T-scan computational software, including specific words (content words, frequent, concrete and abstract nouns, and fillers), lexical complexity (lemma frequency, Type-Token-Ratio) and syntactic complexity (Developmental Level scale). Nineteen individuals (30%) had high levels of amyloid burden, and there were no differences between groups on conventional neuropsychological tests. Using multinomial regression with linguistic parameters (in tertiles), we found that high amyloid burden is associated with fewer concrete nouns (OR_middle (95%CI): 7.6 (1.4-41.2), OR_lowest: 6.7 (1.2-37.1)) and content words (OR_lowest: 6.3 (1.0-38.1). In addition, we found an interaction for education between high amyloid burden and more abstract nouns. In conclusion, high amyloid burden was modestly associated with fewer specific words, but not with syntactic complexity, lexical complexity or conventional neuropsychological tests, suggesting that subtle spontaneous speech deficits might occur in preclinical AD.

Impaired comprehension of metaphorical expressions in very mild Alzheimer's disease

BACKGROUND

Brain-damaged patients often have difficulty understanding non-literal language. However, whether patients with Alzheimer's disease (AD) have comprehension deficits of metaphorical expressions, in contrast with non-metaphorical (literal) expressions, remains unclear.

PATIENTS AND METHODS

The subjects were 40 AD patients; 20 had mild AD (17-23 points on the Mini-Mental State Examination [MMSE]), and 20 had very mild AD (≥24 points). Twenty normal elderly controls were also enrolled as a control group. Thirty sentences that contained novel similes (Items) were prepared. For each Item, four explanatory choices, consisting of one correct response and three foils, were provided. The participants were asked to choose the written statement that best represented the Item's meaning. In addition, all the subjects completed the Token Test.

RESULTS

The patients with mild AD had significantly lower scores than the normal controls on both the simile comprehension test and the Token Test. However, the patients with very mild AD exhibited significantly lower scores on the simile comprehension test, but not on the Token Test. The distributions of error types for the simile test differed between the mild AD group and the other groups. The mild AD patients made more errors that were "far" from the correct responses.

CONCLUSION

Patients with AD are more likely to have comprehension deficits of metaphorical expressions than comprehension deficits of non-metaphorical expressions. Pragmatic language dysfunction may precede formal language dysfunction during the progression of AD.

Do adapted vignettes improve medical decision-making capacity for individuals with Alzheimer's disease?

Medical decision-making capacity (MDC) is known to decline in individuals with Alzheimer's disease (AD). The vignette method uses hypothetical information as a prerequisite for measuring the capacity to make well-informed decisions to clinical trials. Our aim was to investigate if adapted vignettes can help individuals with mild AD to assimilate information, make decisions and express them in an understandable way, compared to corresponding decisions based on linguistically more demanding vignettes, as measured by the Swedish Linguistic Instrument for Medical Decision-making (LIMD). Two vignettes from LIMD were altered linguistically with the aim to facilitate understanding for individuals with AD. An experimental within-subject design was used to study the influence on MDC of readability (original/adapted vignettes) and content (two different clinical trials). We included 24 patients with mild AD in this prospective study, which read all four vignettes along with a few other tests. This allowed us to investigate the association between MDC and cognitive function. Adapted vignettes did not yield significant differences regarding MDC as compared with original vignettes using a two-way repeated measures analysis of variance. A difference was found between the two clinical trials where LIMD score was significantly higher for Kidney disease than hypertension vignettes. Our results indicate that adapted vignettes may not improve MDC for individuals with mild AD. MDC was affected by which clinical trial the vignettes regarded, which implies that other factors affecting MDC need to be investigated, like length of text and vocabulary used.

Impaired Processing of Serial Order Determines Working Memory Impairments in Alzheimer's Disease

BACKGROUND

Working memory (WM) problems are commonly observed in Alzheimer's disease (AD), but the affected mechanisms leading to impaired WM are still insufficiently understood. The ability to efficiently process serial order in WM has been demonstrated to be fundamental to fluent daily life functioning. The decreased capability to mentally process serial position in WM has been put forward as the underlying explanation for generally compromised WM performance.

OBJECTIVE

Determine which mechanisms, such as order processing, are responsible for deficient WM functioning in AD.

METHOD

A group of AD patients (n = 32) and their partners (n = 25), assigned to the control group, were submitted to an extensive battery of neuropsychological and experimental tasks, assessing general cognitive state and functioning of several aspects related to serial order WM.

RESULTS

The results revealed an impaired ability to bind item information to serial position within WM in AD patients compared to controls. It was additionally observed that AD patients experienced specific difficulties with directing spatial attention when searching for item information stored in WM.

CONCLUSION

The processing of serial order and the allocation of attentional resources are both disrupted, explaining the generally reduced WM functioning in AD patients. Further studies should now clarify whether this observation could explain disease-related problems for other cognitive functions such as verbal expression, auditory comprehension, or planning.

A pilot-feasibility study of measuring emotional expression during oral care

This study explored the feasibility of measuring emotional responses to oral care among individuals with dementia living in residential long-term care (LTC). Eleven residents with dementia were recruited from a U.S. Department of Veterans Affairs LTC unit and were observed eight times before, during, and after oral care episodes. Study participants showed a trend toward more positive emotional expressions during and after oral care (mean ± SD: 6.49 ± 1.57 and 6.27 ± 1.20 respectively) than before oral care (6.15 ± 0.86) at the margin of statistical significance (p = .08). Negative emotional expression increased among participants during oral care, from 0.22 ± .35 expressions per minute to 0.60 ± .65 expressions per minute, but returned to baseline after oral care (p < .01). Future studies with more representative samples are needed to more fully examine emotional responses to different types of care, adjusting for potential confounders, and to determine whether residents' emotional responses influence staff members' provision of care.

Characteristics of Agraphia in Chinese Patients with Alzheimer's Disease and Amnestic Mild Cognitive Impairment

Background:

Patients with Alzheimer's disease (AD) manifest progressive decline in writing abilities. Most studies on agraphia in AD have been performed in the alphabetic system, such as English. However, these findings may not be applicable to other written language systems. The unique features of the Chinese written script could affect the patterns of agraphia in Chinese AD patients. The aim of this study was to explore the features of writing errors in Chinese patients with AD and amnestic mild cognitive impairment (a-MCI), as well as to study the relationship between their writing errors and neuropsychological functions.

Methods:

In this study, we performed an observational study in a group of subjects including 17 AD patients, 14 patients with a-MCI, and 16 elderly healthy controls. We analyzed the writing errors in these subjects and also studied the relationship between their writing errors and neuropsychological functions.

Results:

Our study showed that in patients whose mother tongue is Chinese, writing ability was comparatively well preserved in the MCI phase but significantly impaired when the disease progressed to the stage of AD. The writing errors showed corresponding increase with the severity of cognition decline, both in the types of errors and rate of occurrence. Analysis of the writing errors showed that word substitution and unintelligible words were the most frequent error types that occurred in all the three study groups. The occurrence rate of unintelligible words was significantly higher in the AD group compared with the a-MCI group (P = 0.024) and control group (P = 0.018). In addition, the occurrence rates of word substitution were also significantly higher in AD (P = 0.013) and a-MCI groups (P = 0.037) than that of control group. However, errors such as totally no response, visuospatial impairment, paragraph agraphia, ideograph, and perseverative writing errors were only seen in AD group. Besides, we also found a high occurrence rate of visuoconstructional errors (13.3%) in our AD group.

Conclusions:

Our study confirmed that agraphia is an important feature in patients with AD. The writing error profile in patients whose native language is Chinese was unique compared to patients using the alphabetic language system.

Vocabulary Size in Speech May Be an Early Indicator of Cognitive Impairment

Little is known about the relationship between mild cognitive impairment (MCI) and changes to language abilities. Here, we used the revised Hasegawa Dementia Scale (HDS-R) to identify suspected MCI in elderly individuals. We then analyzed written and spoken narratives to compare the language abilities between study participants with and without MCI in order to explore the relationship between cognitive and language abilities, and to identify a possible indicator for the early detection of MCI and dementia. We recruited 22 people aged 74 to 86 years (mean: 78.32 years; standard deviation: 3.36). The participants were requested to write and talk about one of the happiest events in their lives. Based on HDS-R scores, we divided the participants into 2 groups: the MCI Group comprised 8 participants with a score of 26 or lower, while the Healthy Group comprised 14 participants with a score of 27 or higher. The transcriptions of both written and spoken samples for each participant were used in the measurement of NLP-based language ability scores. Our analysis showed no significant differences in writing abilities between the 2 groups in any of the language ability scores. However, analysis of the spoken narrative showed that the MCI Group had a significantly larger vocabulary size. In addition, analysis of a metric that signified the gap in content between the spoken and written narratives also revealed a larger vocabulary size in the MCI Group. Individuals with early-stage MCI may be engaging in behavior to conceal their deteriorating cognition, thereby leading to a temporary increase in their active spoken vocabulary. These results indicate the possible detection of early stages of reduced cognition before dementia onset through the analysis of spoken narratives.

Speaking in Alzheimer's Disease, is That an Early Sign? Importance of Changes in Language Abilities in Alzheimer's Disease

It is known that Alzheimer’s disease (AD) influences the temporal characteristics of spontaneous speech. These phonetical changes are present even in mild AD. Based on this, the question arises whether an examination based on language analysis could help the early diagnosis of AD and if so, which language and speech characteristics can identify AD in its early stage. The purpose of this article is to summarize the relation between prodromal and manifest AD and language functions and language domains. Based on our research, we are inclined to claim that AD can be more sensitively detected with the help of a linguistic analysis than with other cognitive examinations. The temporal characteristics of spontaneous speech, such as speech tempo, number of pauses in speech, and their length are sensitive detectors of the early stage of the disease, which enables an early simple linguistic screening for AD. However, knowledge about the unique features of the language problems associated with different dementia variants still has to be improved and refined.

Verbal fluency, naming and verbal comprehension: three aspects of language as predictors of cognitive impairment

OBJECTIVES

To establish the possible relationship among three components of language (verbal fluency, naming and comprehension) and cognitive impairment as well as to determine the usefulness of language assessment tests to predict or monitor the development of cognitive impairment.

METHOD

A comparative, descriptive and cross-sectional study was performed on 82 subjects ≥ 65 years of age who were cognitively assessed with the Mini Mental State Examination and were divided into two groups: Group A comprised of subjects classified as levels 1, 2 and 3 on the Reisberg's Global Deterioration Scale (GDS) and group B comprised of subjects at levels 4 and 5 of the GDS. Language skills were assessed by the Verbal Fluency Test, Boston Naming Test and Token Test.

RESULTS

An inverse relationship between performance on language tests and cognitive impairment level was observed with a more pronounced effect observed on fluency and comprehension tests.

CONCLUSION

Language assessments, especially fluency and comprehension, were good indicators of cognitive impairment. The use of these assessments as predictors of the degree of cognitive impairment is discussed in-depth.

The Bedford Alzheimer nursing-severity scale to assess dementia severity in advanced dementia: a nonparametric item response analysis and a study of its psychometric characteristics

The Bedford Alzheimer Nursing-Severity Scale (BANS-S) assesses disease severity in patients with advanced Alzheimer's disease. Since Alzheimer is a progressive disease, studying the hierarchy of the items in the scale can be useful to evaluate the progression of the disease. Data from 164 Alzheimer's patients and 186 patients with other dementia were analyzed using the Mokken Scaling Methodology to determine whether respondents can be ordered in the trait dementia severity, and to study whether an ordering between the items exist. The scalability of the scale was evaluated by the H coefficient. Results showed that the BANS-S is a reliable and medium scale (0.4≤H<0.5) for the Alzheimer group. All items with the exception of the item about mobility could be ordered. When later item was eliminated from the scale, the H coefficient decreased indicating that the scalability of the scale in the original form is more accurate than in the shorter version. For the other dementia group, the BANS-S did not fit any of the Mokken Scaling models because the scale was not unidimensional. In this group, a shorter version of the scale without the sleeping cycle item and the mobility item has better reliability and scalability properties than the original scale.

Semantic memory and language dysfunction in early Alzheimer's disease: a review

BACKGROUND

Language impairment in Alzheimer's disease occurs early, and language function deteriorates with progression of the illness to cause significant disability. This review focuses on language dysfunction in Alzheimer's disease and the contribution of semantic memory impairment.

METHODS

Electronic publication databases were searched for literature relevant to the review. Additionally, individual references were examined to elicit further studies not found by online search.

RESULTS

Language impairment in Alzheimer's disease initially affects verbal fluency and naming before breakdown in other facets. Naming and fluency require integrity of semantic concepts, and dysfunction may be a marker of primary semantic memory impairment rather than overall cognitive decline. Research suggests the presence of semantic loss several years prior to diagnosis. Imaging studies indicate an altered connectivity state with respect to language networks, and this is associated with potential semantic failure. This state may also be present in individuals with established risk factors for Alzheimer's disease. Compensatory recruitment of alternative cortical areas to supplement language function appears to occur and may be a target for future intervention.

CONCLUSIONS

Identifying and classifying the nature and degree of language impairment more closely could aid in developing targeted therapies. Treatments already established in other aphasic states, such as post-stroke, may be especially relevant. The nature of these and the protective nature of cognitive reserve are potential therapeutic avenues.

Neuropsychology of Alzheimer's disease

The expression of neurodegenerative diseases can be categorized into three main symptomatic domains: neurological, cognitive and, neuropsychiatric. This review focuses on the cognitive profile and neuropsychological assessment of Alzheimer's disease (AD). The topography and progression of brain neuropathology determines the cognitive expression of the disease. Thus, in accordance with the initial involvement of the medial temporal lobe, cognitive changes in AD start with specific difficulties in encoding and storage of new information. This particular memory deficit can be optimally detected with memory tests that enhance mnemonic retrieval by means of encoding specificity technique such as the Free and Cued Selective Reminding Test (FCSRT). Along the course of the disease, the neuropathology spreads to association cortices, and other neuropsychological deficits can be detected. A comprehensive neuropsychological examination encompassing several cognitive domains can provide a pattern of altered and preserved functions that is helpful to early detection, differential diagnosis and even prognosis of progression in predementia stages. The use of adapted and standardized instruments is necessary to properly estimate cognitive and functional performance in AD.

Oral reading fluency analysis in patients with Alzheimer disease and asymptomatic control subjects

INTRODUCTION

Many studies highlight that an impaired ability to communicate is one of the key clinical features of Alzheimer disease (AD).

OBJECTIVE

To study temporal organisation of speech in an oral reading task in patients with AD and in matched healthy controls using a semi-automatic method, and evaluate that method's ability to discriminate between the 2 groups.

SUBJECTS AND METHODS

A test with an oral reading task was administered to 70 subjects, comprising 35 AD patients and 35 controls. Before speech samples were recorded, participants completed a battery of neuropsychological tests. There were no differences between groups with regard to age, sex, or educational level.

RESULTS

All of the study variables showed impairment in the AD group. According to the results, AD patients' oral reading was marked by reduced speech and articulation rates, low effectiveness of phonation time, and increases in the number and proportion of pauses. Signal processing algorithms applied to reading fluency recordings were shown to be capable of differentiating between AD patients and controls with an accuracy of 80% (specificity 74.2%, sensitivity 77.1%) based on speech rate.

CONCLUSION

Analysis of oral reading fluency may be useful as a tool for the objective study and quantification of speech deficits in AD.

Current concepts in Alzheimer's disease: a multidisciplinary review

This comprehensive, pedagogically-oriented review is aimed at a heterogeneous audience representative of the allied disciplines involved in research and patient care. After a foreword on epidemiology, genetics, and risk factors, the amyloid cascade model is introduced and the main neuropathological hallmarks are discussed. The progression of memory, language, visual processing, executive, attentional, and praxis deficits, and of behavioral symptoms is presented. After a summary on neuropsychological assessment, emerging biomarkers from cerebrospinal fluid assays, magnetic resonance imaging, nuclear medicine, and electrophysiology are discussed. Existing treatments are briefly reviewed, followed by an introduction to emerging disease-modifying therapies such as secretase modulators, inhibitors of Abeta aggregation, immunotherapy, inhibitors of tau protein phosphorylation, and delivery of nerve growth factor.

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.

Word-finding difficulty: a clinical analysis of the progressive aphasias

The patient with word-finding difficulty presents a common and challenging clinical problem. The complaint of 'word-finding difficulty' covers a wide range of clinical phenomena and may signify any of a number of distinct pathophysiological processes. Although it occurs in a variety of clinical contexts, word-finding difficulty generally presents a diagnostic conundrum when it occurs as a leading or apparently isolated symptom, most often as the harbinger of degenerative disease: the progressive aphasias. Recent advances in the neurobiology of the focal, language-based dementias have transformed our understanding of these processes and the ways in which they breakdown in different diseases, but translation of this knowledge to the bedside is far from straightforward. Speech and language disturbances in the dementias present unique diagnostic and conceptual problems that are not fully captured by classical models derived from the study of vascular and other acute focal brain lesions. This has led to a reformulation of our understanding of how language is organized in the brain. In this review we seek to provide the clinical neurologist with a practical and theoretical bridge between the patient presenting with word-finding difficulty in the clinic and the evidence of the brain sciences. We delineate key illustrative speech and language syndromes in the degenerative dementias, compare these syndromes with the syndromes of acute brain damage, and indicate how the clinical syndromes relate to emerging neurolinguistic, neuroanatomical and neurobiological insights. We propose a conceptual framework for the analysis of word-finding difficulty, in order both better to define the patient's complaint and its differential diagnosis for the clinician and to identify unresolved issues as a stimulus to future work.

A New Test Battery to Assess Aphasic Disturbances and Associated Cognitive Dysfunctions — German Normative Data on the Aphasia Check List

Aphasia, defined as an acquired impairment of linguistic abilities, can be accompanied by a diversity of neuropsychological dysfunction. Accordingly, the necessity to include cognitive testing in the diagnosis of aphasia is increasingly recognized. Here we present the Aphasia Check List (ACL), a new test battery for the assessment of aphasic and associated cognitive disorders. The language part of the battery provides a differentiated profile of important linguistic abilities. In addition, the ACL includes nonverbal screening tests for three neuropsychological domains: memory, attention, and reasoning. Dysfunctions in these domains have been observed in aphasic patients and can have an impact on language function. The ACL is applicable to patients with language disturbances of different etiologies, different stages of disease, and to patients with mild to severe aphasia. As the entire test duration is only about 30 minutes, the ACL is also economically valuable. It thus presents an adequate starting point in aphasia diagnosis for a wide range of patients. Here we describe the construction of the ACL, and the normative study of its original German version with 154 aphasic patients and 106 healthy comparison subjects. The ACL cognition part revealed additional neuropsychological dysfunction in the aphasia group. We present the patterns of these dysfunctions and their correlations with language deficits.

Noninfarct vascular dementia and Alzheimer dementia spectrum

Vascular dementia is an overarching superordinate category of which multiinfarct vascular dementia is only one subtype. To contribute to the definition of vascular dementia, method involved investigation of mental status, oral language and comprehension in 81 consecutive vascular patients comprising two vascular samples: cerebral infarct sample (n=43) and cerebral noninfarct sample (n=38). To determine baseline, method also involved investigation of 36 demographically equivalent normal elderly. Results indicate both vascular samples performed significantly worse than normal elderly. Results further indicate there were no robust, reliable, significant differences between cerebral infarct and cerebral noninfarct patients. The lack of significant differences between cerebral infarct and cerebral noninfarct vascular samples brings into focus the ambiguous transition between diffuse, generalized disease and the multifocality underlying the vascular dementia-Alzheimer dementia spectrum. Cross-cutting infarct and noninfarct vascular populations were vascular factors of arteriosclerosis, abnormal blood pressure, diabetes mellitus, abnormal electrocardiogram, peripheral vascular disease, and other variables implicated in the distal causality of both infarct and noninfarct vascular dementias. Results indicate cerebral infarction is not the only path to the final common phenotype of vascular dementia. Vascular dementia is reconceptualized so as to include noninfarct vascular dementia: vascular dementia caused by underlying vascular factors other than cerebral infarction. It is suggested that one form of the subtype of noninfarct vascular dementia is Alzheimer-type vascular dementia.

A comparison of verbal and written language in Alzheimer's disease

Few studies have examined characteristics of both verbal and written language of individuals with Alzheimer's disease (AD). This study used parallel measures (picture description, word fluency, spelling to dictation, and confrontational naming) to compare verbal and written language of individuals with mild AD, moderate AD, and normal controls (14 participants per group). Goals were to determine whether verbal/written differences would be exhibited within groups, and to identify measures sensitive to the effects of mild AD. Results showed that increasing AD severity led to decline in performance for most tasks, but only word fluency differentiated subjects with mild AD from normal controls. Confrontational naming was the only task to identify a difference in verbal and written performance for an AD group but not controls; moderate AD subjects performed worse in written naming. Similar verbal and written performance for the spelling to dictation task indicates impairment to central spelling processes in AD.

LEARNING OUTCOMES

As a result of this activity, participants will be able to: (1) identify verbal and written language measures which are sensitive to the effects of mild AD; (2) describe similarities and differences in verbal and written language performance among mild AD subjects, moderate AD subjects, and controls; (3) describe how findings may inform clinical practice for individuals with mild AD.