Language function in senile dementia

Seeing beyond the symptoms: biomarkers and brain regions linked to cognitive decline in Alzheimer's disease

Objective

Early Alzheimer's disease (AD) diagnosis remains challenging, necessitating specific biomarkers for timely detection. This study aimed to identify such biomarkers and explore their associations with cognitive decline.

Methods

A cohort of 1759 individuals across cognitive aging stages, including healthy controls (HC), mild cognitive impairment (MCI), and AD, was examined. Utilizing nine biomarkers from structural MRI (sMRI), diffusion tensor imaging (DTI), and positron emission tomography (PET), predictions were made for Mini-Mental State Examination (MMSE), Clinical Dementia Rating Scale Sum of Boxes (CDRSB), and Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS). Biomarkers included four sMRI (e.g., average thickness [ATH]), four DTI (e.g., mean diffusivity [MD]), and one PET Amyloid-β (Aβ) measure. Ensemble regression tree (ERT) technique with bagging and random forest approaches were applied in four groups (HC/MCI, HC/AD, MCI/AD, and HC/MCI/AD).

Results

Aβ emerged as a robust predictor of cognitive scores, particularly in late-stage AD. Volumetric measures, notably ATH, consistently correlated with cognitive scores across early and late disease stages. Additionally, ADAS demonstrated links to various neuroimaging biomarkers in all subject groups, highlighting its efficacy in monitoring brain changes throughout disease progression. ERT identified key brain regions associated with cognitive scores, such as the right transverse temporal region for Aβ, left and right entorhinal cortex, left inferior temporal gyrus, and left middle temporal gyrus for ATH, and the left uncinate fasciculus for MD.

Conclusion

This study underscores the importance of an interdisciplinary approach in understanding AD mechanisms, offering potential contributions to early biomarker development.

The Generalizability of Longitudinal Changes in Speech Before Alzheimer's Disease Diagnosis

BACKGROUND

Language impairment in Alzheimer's disease (AD) has been widely studied but due to limited data availability, relatively few studies have focused on the longitudinal change in language in the individuals who later develop AD. Significant differences in speech have previously been found by comparing the press conference transcripts of President Bush and President Reagan, who was later diagnosed with AD.

OBJECTIVE

In the current study, we explored whether the patterns previously established in the single AD-healthy control (HC) participant pair apply to a larger group of individuals who later receive AD diagnosis.

METHODS

We replicated previous methods on two larger corpora of longitudinal spontaneous speech samples of public figures, consisting of 10 and 9 AD-HC participant pairs. As we failed to find generalizable patterns of language change using previous methodology, we proposed alternative methods for data analysis, investigating the benefits of using different language features and their change with age, and compiling the single features into aggregate scores.

RESULTS

The single features that showed the strongest results were moving average type:token ratio (MATTR) and pronoun-related features. The aggregate scores performed better than the single features, with lexical diversity capturing a similar change in two-thirds of the participants.

CONCLUSION

Capturing universal patterns of language change prior to AD can be challenging, but the decline in lexical diversity and changes in MATTR and pronoun-related features act as promising measures that reflect the cognitive changes in many participants.

Sentence comprehension in patients with dementia of the Alzheimer's type

Sentence comprehension is diminished in patients with dementia of the Alzheimer’s type (DAT). However, the underlying reason for such deficits is still not entirely clear. The Syntactic Deficit Hypothesis attributes sentence comprehension deficits in DAT patients to the impairment in syntactic ability, whereas the Processing Resource Deficit Hypothesis proposes that sentence comprehension deficits are the result of working memory deficiency. This study investigated the deficits in sentence comprehension in Chinese-speaking DAT patients with different degrees of severity using sentence-picture matching tasks. The study revealed a significant effect of syntactic complexity in patients and healthy controls, but the effect was stronger in patients than in healthy controls. When working memory demand was minimized, the effect of syntactic complexity was only significant in patients with moderate DAT, but not in healthy controls or those with mild DAT. The findings suggest that in patients with mild DAT, working memory decline was the major source of sentence comprehension difficulty and in patients with moderate DAT, working memory decline and syntactic impairment jointly contributed to the impairments in sentence comprehension. The source of sentence comprehension deficits varied with degree of dementia severity.

Language Disorders in Huntington Disease: A Systematic Literature Review

OBJECTIVE

A systematic review examining the presence and nature of language disorders associated with Huntington disease (HD).

BACKGROUND

HD is characterized by gradual motor dysfunction, psychiatric problems, and cognitive decline. Communication abilities in HD may be affected not only by dysarthria but also by language impairment. However, the nature and type of this impairment is not well defined.

METHODS

We searched the PubMed and PsycINFO databases and selected studies on the basis of the original language of the article, peer-review status, and specificity of the results regarding language and communication disorders.

RESULTS

Thirty-one articles meeting the selection criteria were selected for this review. According to most of the studies, individuals with HD present with primary deficits of language. However, a few authors suggested that language deficits in HD result from nonlinguistic impairments, or that language abilities are largely preserved. More specifically, studies showed that HD is associated with difficulties in producing and understanding sentences and discourse, processing semantic representations of object and action concepts, retrieving lexical forms of nouns, and applying morphological and syntactic rules. There is some disagreement regarding whether HD affects reading abilities, sentence production, semantic processing, and application of morphological rules in verb conjugation.

CONCLUSIONS

Although people with HD present with language impairment, further studies are needed to identify their functional origin. Clinical studies are also needed to determine the impact of such impairments on an individual's functional communication in daily living and to chart the progression of the impairments over the course of the disease.

Identification of Mild Cognitive Impairment From Speech in Swedish Using Deep Sequential Neural Networks

While people with mild cognitive impairment (MCI) portray noticeably incipient memory difficulty in remembering events and situations along with problems in decision making, planning, and finding their way in familiar environments, detailed neuropsychological assessments also indicate deficits in language performance. To this day, there is no cure for dementia but early-stage treatment can delay the progression of MCI; thus, the development of valid tools for identifying early cognitive changes is of great importance. In this study, we provide an automated machine learning method, using Deep Neural Network Architectures, that aims to identify MCI. Speech materials were obtained using a reading task during evaluation sessions, as part of the Gothenburg MCI research study. Measures of vowel duration, vowel formants (F1 to F5), and fundamental frequency were calculated from speech signals. To learn the acoustic characteristics associated with MCI vs. healthy controls, we have trained and evaluated ten Deep Neural Network Architectures and measured how accurately they can diagnose participants that are unknown to the model. We evaluated the models using two evaluation tasks: a 5-fold crossvalidation and by splitting the data into 90% training and 10% evaluation set. The findings suggest first, that the acoustic features provide significant information for the identification of MCI; second, the best Deep Neural Network Architectures can classify MCI and healthy controls with high classification accuracy (M = 83%); and third, the model has the potential to offer higher accuracy than 84% if trained with more data (cf., SD≈15%). The Deep Neural Network Architecture proposed here constitutes a method that contributes to the early diagnosis of cognitive decline, quantify the progression of the condition, and enable suitable therapeutics.

Speech therapy for psychogeriatric services

A psychogeriatrician was recently given the opportunity of five sessions of speech therapy for his service. His response was that he had no need of a speech therapist as he was perfectly well able to do his own assessment of dysphasia. This attitude is perhaps understandable since there has been so little exposure to the skills of speech therapists within this clinical field. In 1985 a full-time speech therapist was appointed by Central Manchester Health Authority to be part of the multidisciplinary team working in old age psychiatry. At the time this was, to our knowledge, the first full-time position of its kind. This article reviews progress thus far and outlines the contribution of speech therapy skills to the management of the elderly mentally ill.

A Speech Recognition-based Solution for the Automatic Detection of Mild Cognitive Impairment from Spontaneous Speech

BACKGROUND

Even today the reliable diagnosis of the prodromal stages of Alzheimer's disease (AD) remains a great challenge. Our research focuses on the earliest detectable indicators of cognitive decline in mild cognitive impairment (MCI). Since the presence of language impairment has been reported even in the mild stage of AD, the aim of this study is to develop a sensitive neuropsychological screening method which is based on the analysis of spontaneous speech production during performing a memory task. In the future, this can form the basis of an Internet-based interactive screening software for the recognition of MCI.

METHODS

Participants were 38 healthy controls and 48 clinically diagnosed MCI patients. The provoked spontaneous speech by asking the patients to recall the content of 2 short black and white films (one direct, one delayed), and by answering one question. Acoustic parameters (hesitation ratio, speech tempo, length and number of silent and filled pauses, length of utterance) were extracted from the recorded speech signals, first manually (using the Praat software), and then automatically, with an automatic speech recognition (ASR) based tool. First, the extracted parameters were statistically analyzed. Then we applied machine learning algorithms to see whether the MCI and the control group can be discriminated automatically based on the acoustic features.

RESULTS

The statistical analysis showed significant differences for most of the acoustic parameters (speech tempo, articulation rate, silent pause, hesitation ratio, length of utterance, pause-per-utterance ratio). The most significant differences between the two groups were found in the speech tempo in the delayed recall task, and in the number of pauses for the question-answering task. The fully automated version of the analysis process - that is, using the ASR-based features in combination with machine learning - was able to separate the two classes with an F1-score of 78.8%.

CONCLUSION

The temporal analysis of spontaneous speech can be exploited in implementing a new, automatic detection-based tool for screening MCI for the community.

Compensatory strategies in picture description across severity levels in Alzheimer's disease: A longitudinal study

Communication changes over time were studied in 55-persons with Alzheimer's disease (AD) who completed a picture description task at entry, six, and 12-months. Differences at three levels of AD severity (early, middle, late) were investigated using six discourse measures (total utterances, length of utterance, words, abandoned utterances, information units, and conciseness), and six pragmatic measures (questions, turns, unsure statements, judgments, egocentric comments, and giving names). Across all three groups, subjects were less concise over time, made shorter utterances, asked more questions, and provided fewer information units. Increasing percentages of subjects made unsure statements with time. However, performance varied by severity group, with increasing unsureness occurring only at early AD, and all other observed changes occurring at late AD. Persons with AD appear to strive for communication competence as language declines by increasing certain compensatory pragmatic aspects (questions and unsure statements) at different severity levels of the disorder. This suggests that compensatory pragmatic devices are used with flexibility, and that the desire to communicate is maintained throughout the course of AD.

Procedural discourse of men and women with Alzheimer's disease: A longitudinal study with clinical implications

Measures of procedural discourse, verbal instructions that tell how a task is accomplished, in 60 persons with Alzheimer's disease (AD) (29 men, 31 women) and 50 non demented elderly persons (21 men, 29 women) were compared at entry and 18 months later The measures included seven linguistic elements (statements, abandoned utterances, mazes, number of different words used in relation to total words, length of utterances, questions, and interrupted utterances) and four procedural elements (essential steps, optional steps, off topic utterances, and repetitions of steps). Gender patterns were examined in both groups over time. Results showed that AD subjects used fewer statements and produced longer utterances; AD subjects provided fewer essential and optional steps; AD subjects showed a sharp decline over time with fewer statements, more questions, and fewer essential steps. AD men and women performed similarly. Clinicians can gain significant information about language and cognitive function of persons with AD by including procedural discourse in the evaluation protocol.

A systematic narrative review of support groups for people with dementia

BACKGROUND

Provision of non-pharmacological interventions is a common policy objective for people with dementia, and support groups are an increasingly common intervention. However, there have been few attempts to synthesize evidence on the effectiveness of support groups for people with dementia. This review investigated the outcomes of support groups for people with dementia, explored participant characteristics and reviewed group formats.

METHODS

A systematic review was undertaken and a narrative synthesis of data from 29 papers (reporting on 26 groups and a survey of a range of groups) was conducted.

RESULTS

Support groups seem acceptable to people with dementia. Qualitative studies report subjective benefits for participants but there is limited evidence of positive outcomes based on quantitative data. Samples have tended to be homogenous and this may limit the generalizability of findings.

CONCLUSIONS

Although qualitative studies will remain important in this area, further mixed-methods randomized controlled trials (RCTs)or comparison group studies with longer follow-up periods are needed to strengthen the evidence base.

Wechsler Adult Intelligence Scale-III profile in the early stages of Alzheimer's disease: performance in subtests sensitive to and resistant to normal decline with ageing

AIM

This study examined the significance of age-related subtest scores from the Japanese version of the Wechsler Adult Intelligence Scale-III in patients in the early stages of Alzheimer's disease (AD).

METHODS

The subjects of this study included 58 elderly Japanese persons classified into two groups: AD group (n = 29) and control group (n = 29). These groups did not differ in age, years of education, gender ratio, Hasegawa's Dementia Scale-Revised score, or Full-Scale IQ score. No subject scored below the cut-off point on Hasegawa's Dementia Scale-Revised, a frequently used dementia screen test in Japan.

RESULTS

At the index score level, General Ability Index scores were the only scores that differed significantly between the groups, with the AD group scoring significantly lower than the control group (P < 0.05, Hedges' g = 0.54). At the subtest level, information scores were the only scores that differed significantly between the groups, with the AD group significantly lower than the control group (P < 0.01, Hedges' g = 0.74).

CONCLUSION

The General Ability Index is a composite score that deducts components of working memory and processing speed, which are sensitive to decline with normal ageing, from the Full-Scale IQ. It also served as a subtest measuring crystallized intelligence, especially of acquired knowledge of general and factual information. Therefore, the results of this study seem to suggest that Wechsler Adult Intelligence Scale-III profile of very early AD may be characterized by weak performance on subtests normally resistant to decline with ageing.

A Review of Self-Management Interventions for People With Dementia and Mild Cognitive Impairment

Self-management offers a way of helping people with dementia or mild cognitive impairment (MCI) to play an active role in managing their condition. Barlow, Wright, Sheasby, Turner, and Hainsworth have defined self-management as the "individual's ability to manage the symptoms, treatment, physical and psychosocial consequences and life style changes inherent in living with a chronic condition." Although commonly used in other chronic health conditions, there has been relatively little exploration of the role of self-management in dementia or MCI. This review aimed to identify group-based psychosocial interventions for people with dementia or MCI that incorporate significant elements of self-management. Fifteen interventions were included in the review: 12 for people with dementia and 3 for participants with MCI. In both the dementia and MCI interventions, the most commonly included self-management components were information, communication, and social support, and skills training. The review findings indicate that components of self-management have been incorporated into group-based interventions for people with dementia and MCI. Further studies are needed to address the methodological limitations of the included studies and to determine the effectiveness of self-management interventions with these populations.

Help yourself: perspectives on self-management from people with dementia and their caregivers

Self-management interventions are increasingly offered to people with chronic health conditions. However, there has been limited exploration of how applicable such an approach is in early stage dementia. In this study we explored the views of people with dementia and family caregivers on the use of self-management in dementia. We conducted semistructured interviews with 13 people with early stage dementia and 11 caregivers. We analyzed transcripts using thematic analysis. We found eight themes in the analysis, and they indicated that self-management occurs in the context of peoples' family and social relationships as well as relationships with professional services. Six of the themes involved barriers to and facilitators of self-management. It is evident from these findings that people with dementia and caregivers use self-management techniques. Their use of such techniques could be enhanced by the development of interventions designed to help people with dementia to develop their self-management skills.

Changes in communication of Deaf people with dementia: A thematic interview with a close family member

BACKGROUND AND AIM

Learning about changes in communication of Deaf with dementia (DWD) is important in order to improve services and support DWD and their families. We explored family members' views on the changes in communication DWD have and the ways communication was adapted due to progression of dementia.

METHODS

A qualitative content analysis of thematic interviews that were conducted with eight close family members of DWD.

RESULTS

With decreasing vocabulary and increasing sign-finding difficulties, conversations became poorer, and DWD tended to diverge from the topic. Nonverbal communication became more important as the verbal communication abilities of DWD deteriorated, and the adult children took a more active role by taking initiative and guiding conversations.

CONCLUSION

DWD seem to go through similar changes in communication as hearing people with dementia. Adult children of DWD need to get used to interpreting and assisting their parent's communication through different phases of dementia.

Development of Six Arts, a Culturally Appropriate Multimodal Nonpharmacological Intervention in Dementia

PURPOSE

There is accumulating evidence for the efficacy of nonpharmacological multimodal stimulation interventions in maintaining cognition and improving quality of life in people with mild-to-moderate dementia. However, the complex nature of these interventions limits their application in practice and research. We report here the design and development of a culturally appropriate framework, the Six Arts, to guide delivery of multimodal interventions in a Chinese community.

DESIGN AND DEVELOPMENT

The Six Arts are a core set of Confucian philosophy comprising 6 disciplines of rites, music, archery, charioteering, literacy, and numeracy. They correspond to major mind-body functional domains of social functioning; music and rhythm; visuospatial and fine motor skills; kinesthetic and gross motor skills; language and verbal skills; and executive function. Using Six Arts as a framework, we mapped theoretical principles and evidence-based nonpharmacological interventions of cognitive stimulation, physical exercise, and social activities against the 6 functional domains. From 2011, we field-tested the use of Six Arts in structuring intervention programs in 263 people in a dementia day center in Hong Kong.

RESULTS

The Six Arts was operationalized through the development of an intervention activity database, a scoring system for intensity level, and a service delivery model for application in dementia day centers.

IMPLICATIONS

Six Arts can be used as framework for structuring nonpharmacological group intervention programs in dementia day center in a metropolitan Chinese city. Its cultural appropriateness may facilitate communication and shared decision making with families with dementia in communities influenced by Confucian philosophy.

Loss of person-specific knowledge in Alzheimer's disease: evidence from priming

Semantic deficits in Alzheimer's disease (AD) are often more severe for items that are characterized by a unique semantic and lexical association, such as famous people. Whether these deficits are due to the degradation of semantic information or a deficit in the ability to intentionally access semantic knowledge remains controversial. To assess the integrity of the semantic system without explicitly accessing it, a priming paradigm was used. Semantic and repetition priming effects in individuals with AD (n = 7) and age-matched controls (n = 13) were measured in a familiarity judgment task using visually-presented names of famous people. A defective priming effect in AD subjects was observed in the semantic priming but not in the repetition priming condition. Therefore, the semantic impairments observed in AD may indicate a degraded representation of the semantic information concerning famous people.

Matched and mismatched appraisals of the effectiveness of communication strategies by family caregivers of persons with Alzheimer's disease

BACKGROUND

Communication problems stemming from Alzheimer's disease (AD) often result in misunderstandings that can be linked with problem behaviours and increased caregiver stress. Moreover, these communication breakdowns also can result either from caregivers' use of ineffective communication strategies, which paradoxically are perceived as helpful, or can occur as a result of not using effective communication strategies that are perceived as unhelpful.

AIMS

The two primary aims were to determine the effectiveness of strategies used to resolve communication breakdowns and to examine whether caregivers' ratings of strategy effectiveness were consistent with evidence from video-recorded conversations and with effective communication strategies documented in the literature.

METHODS & PROCEDURES

Twenty-eight mealtime conversations were recorded using a sample of 15 dyads consisting of individuals with early, middle and late clinical-stage AD and their family caregivers. Conversations were analysed using the trouble-source repair paradigm to identify the communication strategies used by caregivers to resolve breakdowns. Family caregivers also rated the helpfulness of communication strategies used to resolve breakdowns. Analyses were conducted to assess the overlap or match between the use and appraisals of the helpfulness of communication strategies.

OUTCOMES & RESULTS

Matched and mismatched appraisals of communication strategies varied across stages of AD. Matched appraisals by caregivers of persons with early-stage AD were observed for 68% of 22 communication strategies, whereas caregivers of persons with middle- and late-stage AD had matched appraisals for 45% and 55% of the strategies, respectively. Moreover, caregivers of persons with early-stage AD had matched appraisals over and above making matched appraisals by chance alone, compared with caregivers of persons in middle- and late-stage AD.

CONCLUSIONS & IMPLICATIONS

Mismatches illustrate the need for communication education and training, particularly to establish empirically derived evidence-based communication strategies over the clinical course of AD.

The neuropsychological profile of Alzheimer disease

Neuropsychological assessment has featured prominently over the past 30 years in the characterization of dementia associated with Alzheimer disease (AD). Clinical neuropsychological methods have identified the earliest, most definitive cognitive and behavioral symptoms of illness, contributing to the identification, staging, and tracking of disease. With increasing public awareness of dementia, disease detection has moved to earlier stages of illness, at a time when deficits are both behaviorally and pathologically selective. For reasons that are not well understood, early AD pathology frequently targets large-scale neuroanatomical networks for episodic memory before other networks that subserve language, attention, executive functions, and visuospatial abilities. This chapter reviews the pathognomonic neuropsychological features of AD dementia and how these differ from "normal," age-related cognitive decline and from other neurodegenerative diseases that cause dementia, including cortical Lewy body disease, frontotemporal lobar degeneration, and cerebrovascular disease.

Temporal parameters of spontaneous speech in Alzheimer's disease

This paper reports on four temporal parameters of spontaneous speech in three stages of Alzheimer's disease (mild, moderate, and severe) compared to age-matched normal controls. The analysis of the time course of speech has been shown to be a particularly sensitive neuropsychological method to investigate cognitive processes such as speech planning and production. The following parameters of speech were measured in Hungarian native-speakers with Alzheimer's disease and normal controls: articulation rate, speech tempo, hesitation ratio, and rate of grammatical errors. Results revealed significant differences in most of these speech parameters among the three Alzheimer's disease groups. Additionally, the clearest difference between the normal control group and the mild Alzheimer's disease group involved the hesitation ratio, which was significantly higher in the latter group. This parameter of speech may have diagnostic value for mild-stage Alzheimer's disease and therefore could be a useful aid in medical practice.

The Alzheimer's Disease Centers' Uniform Data Set (UDS): the neuropsychologic test battery

The neuropsychologic test battery from the Uniform Data Set (UDS) of the Alzheimer's Disease Centers (ADC) program of the National Institute on Aging consists of brief measures of attention, processing speed, executive function, episodic memory, and language. This paper describes development of the battery and preliminary data from the initial UDS evaluation of 3268 clinically cognitively normal men and women collected over the first 24 months of utilization. The subjects represent a sample of community-dwelling, individuals who volunteer for studies of cognitive aging. Subjects were considered "clinically cognitively normal" based on clinical assessment, including the Clinical Dementia Rating scale and the Functional Assessment Questionnaire. The results demonstrate performance on tests sensitive to cognitive aging and to the early stages of Alzheimer disease in a relatively well-educated sample. Regression models investigating the impact of age, education, and sex on test scores indicate that these variables will need to be incorporated in subsequent normative studies. Future plans include: (1) determining the psychometric properties of the battery; (2) establishing normative data, including norms for different ethnic minority groups; and (3) conducting longitudinal studies on cognitively normal subjects, individuals with mild cognitive impairment, and individuals with Alzheimer disease and other forms of dementia.

Diagnostic utility of sound naming in early Alzheimer's disease

While it is well known that picture naming (PN) is impaired in Alzheimer's disease (AD), sound naming (SN) has not been thoroughly investigated. We postulated that SN might be impaired more severely and earlier than PN, given the early involvement of the temporal cortex by AD-related pathology. SN and PN were assessed in 21 normal participants, 40 patients with mild cognitive impairment (MCI), and 27 patients in early stages of AD. Our results showed that SN accuracy and latency were more sensitive to advancing pathology in AD than PN accuracy and latency. SN was more useful and specific in distinguishing MCI patients from normal participants and therefore in potentially identifying the subset of MCI patients who already have impairment in more than one cognitive domain and may actually have incipient AD. These findings indicate a potential diagnostic utility of SN for early detection of the disease. Furthermore, even though most AD patients demonstrated more or less comparable impairment in both tasks, some were disproportionately impaired on SN and others were differentially impaired on PN. Future studies may be able to show that these discrepant groups correspond to patients with right and left hemisphere predominant AD, respectively.

Language performance in Alzheimer's disease and mild cognitive impairment: a comparative review

Mild cognitive impairment (MCI) manifests as memory impairment in the absence of dementia and progresses to Alzheimer's disease (AD) at a rate of around 15% per annum, versus 1-2% in the general population. It thus constitutes a primary target for investigation of early markers of AD. Language deficits occur early in AD, and performance on verbal tasks is an important diagnostic criterion for both AD and MCI. We review language performance in MCI, compare these findings to those seen in AD, and identify the primary issues in understanding language performance in MCI and selecting tasks with diagnostic and prognostic value.

Analysis of brief language tests in the detection of cognitive decline and dementia

Lexical access difficulties are frequent in normal aging and initial stages of dementia.Verbal fluency tests are valuable to detect cognitive decline, evidencing lexico-semantic and executive dysfunction.

Alterações de linguagem nas fases iniciais da doença de Alzheimer

A doença de Alzheimer (DA) está associada a alterações cognitivas, de linguagem e de comportamento que se agravam durante seu curso. O objetivo deste estudo foi verificar a presença de alterações de linguagem, em pacientes com DA em fase inicial. Foram avaliados 12 pacientes com diagnóstico de provável (DA). Todos tinham pontuação no Mini Exame do Estado Mental acima de 23 pontos. Os pacientes foram submetidos à aplicação do Teste de Boston e os resultados comparados aos da população normal. Todos os pacientes apresentaram alterações de linguagem. Foram encontradas diferenças estatisticamente significantes nas tarefas de Compreensão auditiva e na tarefa de denominação. Nas demais tarefas de expressão e compreensão oral, bem como nas de leitura e escrita, os pacientes tiveram desempenho similar aos normais. Embora com um grupo pequeno,esta investigação identificou alterações bem definidas de linguagem em uma fase bastante inicial da DA.

Loss of Distinctive Features and a Broader Pattern of Priming in Alzheimer's Disease

The results of 2 experiments support the contention that patients with Alzheimer's disease (AD) show a relative loss of the semantic features that distinguish concepts from one another and that the representations of pairs of concepts consequently share a larger proportion of their associated features in AD than in normal aging. In Experiment 1, AD patients listed fewer features for a set of concepts than did healthy older adults and were more deficient at listing features if the features were distinctive to particular concepts than if they were shared by multiple concepts. In Experiment 2, AD patients showed online priming at levels of relatedness at which healthy older adults did not.

Preserved morphological decomposition in persons with Alzheimer's disease

Persons with Alzheimer's disease (AD) demonstrate a severe lexical impairment that affects conceptual knowledge. Research into aspects of word structure and the structural relationships between words, however, has been scarce in this population. Taking advantage of the rich morphology of Hebrew, the current article examines the status of morphological decomposition in AD. Fourteen persons with AD and 48 control participants completed 2 experiments: The 1st investigated root extraction from pseudoverbs containing existing and nonexisting consonantal roots, and the 2nd looked at sensitivity to morphological priming effects. Results suggest that despite severe semantic-conceptual deficits on naming, fluency, and comprehension tasks, persons with AD engage in adequate morphological decomposition of words, in a similar manner to normal adult speakers of Hebrew.

Confrontation naming does not add incremental diagnostic utility in MCI and Alzheimer's disease

As the incidence of dementia increases, there is a growing need to determine the diagnostic utility of specific neuropsychological tests in the early diagnosis of Alzheimer's disease (AD). In this study, the relative utility of Boston Naming Test (BNT) in the diagnosis of AD was examined and compared to the diagnostic utility of other neuropsychological measures commonly used in the evaluation of AD. Individuals with AD (n = 306), Mild Cognitive Impairment (MCI; n = 67), and cognitively normal subjects (n = 409) with at least 2 annual evaluations were included. Logistic regression analysis suggested that initial BNT impairment is associated with increased risk of subsequent AD diagnosis. However, this risk is significantly less than that imparted by measures of delayed recall impairments. A multivariate Cox proportional hazards regression analysis suggested that BNT impairment imparted no additional risk for subsequent AD diagnosis after delayed recall impairments were included in the model. Although BNT impairment occurred in all severity groups, it was ubiquitous only in moderate to severe dementia. Collectively these results suggest that although BNT impairments become more common as AD progresses, they are neither necessary for the diagnosis of AD nor particularly useful in identifying early AD.

Processing of mass/count information in Alzheimer's disease and mild cognitive impairment

This study examines the processing of a specific linguistic distinction, the mass/count distinction, in patients suffering from Alzheimer's disease (AD) and mild cognitive impairment (MCI). Fourteen AD and 10 MCI subjects were tested using a sentence grammaticality judgement task where grammaticality violations were caused by determiner-noun mismatches, as well as a sentence-picture matching task to assess their ability to access mass and count readings of dual nouns. Considerable heterogeneity was observed within each subject group, and performance across groups was almost identical. It is concluded that a combination of linguistic and attentional and/or learning factors are responsible for the range of impairments; specifically, a subset of subjects exhibit no linguistic nor attentional/learning impairment, another subset exhibit only an attentional and/or learning impairment but no linguistic impairment, and a third subset (comprising more than half of the subjects included in this study) exhibit a linguistic impairment. It is postulated that the latter group have difficulty processing sense extensions in metonymous nouns. It is further claimed that, at least within the limits of the study, language impairments can be of the same severity and nature across AD and MCI subjects.

Contributions of memory circuits to language: the declarative/procedural model

The structure of the brain and the nature of evolution suggest that, despite its uniqueness, language likely depends on brain systems that also subserve other functions. The declarative/procedural (DP) model claims that the mental lexicon of memorized word-specific knowledge depends on the largely temporal-lobe substrates of declarative memory, which underlies the storage and use of knowledge of facts and events. The mental grammar, which subserves the rule-governed combination of lexical items into complex representations, depends on a distinct neural system. This system, which is composed of a network of specific frontal, basal-ganglia, parietal and cerebellar structures, underlies procedural memory, which supports the learning and execution of motor and cognitive skills, especially those involving sequences. The functions of the two brain systems, together with their anatomical, physiological and biochemical substrates, lead to specific claims and predictions regarding their roles in language. These predictions are compared with those of other neurocognitive models of language. Empirical evidence is presented from neuroimaging studies of normal language processing, and from developmental and adult-onset disorders. It is argued that this evidence supports the DP model. It is additionally proposed that "language" disorders, such as specific language impairment and non-fluent and fluent aphasia, may be profitably viewed as impairments primarily affecting one or the other brain system. Overall, the data suggest a new neurocognitive framework for the study of lexicon and grammar.

Sensitivity to gender, person, and tense inflection by persons with Alzheimer's disease

This paper investigates sensitivity to gender, person, and tense inflection in individuals with Alzheimer's disease (AD) in on-line and off-line tasks. Fourteen persons with AD and 14 matched controls participated in two studies: sensitivity to gender incongruity was tested in an on-line reading task and sensitivity to violation of tense and person was tested with an off-line grammaticality judgement test. Group performance was comparable on both tasks. It is argued that patients' preserved sensitivity to these features is primarily a function of the simplicity of the required operations. The notion of simplicity in this context is discussed and various parameters are offered for future investigation.

Categorization of object descriptions in Alzheimer's disease and frontotemporal dementia: limitation in rule-based processing

Studies of semantic memory in probable Alzheimer's disease (AD) have focused on the degradation of semantic knowledge, but other work in AD suggests an impairment in the semantic categorization processes that operate on this knowledge. We examined the categorization of object descriptions, where semantic category membership judgments were based on rule-based or similarity-based categorization processes. We found that AD patients were selectively limited in their semantic categorization under conditions requiring a rule-based approach. However, AD patients did not differ from healthy seniors under conditions based on judgments of overall similarity. We showed that this was not due to nonspecific or overall task-related difficulty associated with the rule condition by asking the subjects to use similarity-based judgments of perceptually degraded versions of the stimuli. The results of this condition did not differ from other similarity-based judgments but did differ from the rule-based condition in AD. Rule-based judgments of semantic category membership correlated with executive measures of inhibitory control and mental search, but not with measures of episodic memory or overall dementia severity, suggesting a contribution of executive resources to rule-based semantic categorization. Moreover, the pattern of limited rule-based categorization in AD closely resembled the performance profile of patients with frontotemporal dementia, further implying that executive resource limitations underlie AD patients' limited rule-based semantic categorization. These findings suggest that semantic memory difficulty in AD is due in part to a deficit in executive processes that are central to rule-based categorization in semantic memory.

Discourse changes in early Alzheimer disease, mild cognitive impairment, and normal aging

The purpose of this study was to determine the sensitivity of discourse gist measures to the early cognitive-linguistic changes in Alzheimer disease (AD) and in the preclinical stages. Differences in discourse abilities were examined in 25 cognitively normal adults, 24 adults with mild probable AD, and 20 adults with mild cognitive impairment (MCI) at gist and detail levels of discourse processing. The authors found that gist and detail levels of discourse processing were significantly impaired in persons with AD and MCI as compared with normal control subjects. Gist-level discourse processing abilities showed minimal overlap between cognitively normal control subjects and those with mild AD. Moreover, the majority of the persons with MCI performed in the range of AD on gist measures. These findings indicate that discourse gist measures hold promise as a diagnostic complement to enhance early detection of AD. Further studies are needed to determine how early the discourse gist deficits arise in AD.

Cognitive resources during sentence processing in Alzheimer's disease

This study assessed sentence comprehension in Alzheimer's disease (AD) while minimizing executive resource demands. AD patients (n=17) and healthy elderly control subjects (n=17) were asked to detect a word in a sentence. Unbeknownst to subjects, the target word at times followed an incorrect grammatical or semantic agreement. Control subjects took significantly longer to respond to a target word when it immediately followed an agreement violation compared to a coherent agreement, a difference that was not evident when the target word followed the agreement by several syllables. AD patients did not demonstrate a discrepancy between a violation and a coherent agreement in the immediate vicinity of the agreement, but demonstrated a significant delay in their response to a target word when it followed an agreement violation--particularly a violation of a grammatical agreement--by several syllables. Analyses of individual patient performance profiles revealed the pattern of delayed sensitivity to agreements in a majority of AD patients. Correlation and regression analyses associated AD patients' sensitivity to agreement violations over an abnormally delayed time course with a measure of inhibitory control, although weaker associations were also evident with measures of planning and short-term memory. We hypothesize that difficulty understanding grammatically complex sentences in AD is related to slowed information processing speed that restricts the timely construction of a sentence's structure and limits inhibition of canonical sentence interpretations such as first-noun-is-subject.

Speech errors in Alzheimer's disease: reevaluating morphosyntactic preservation

Researchers studying the speech of individuals with probable Alzheimer's disease (PAD) report that morphosyntax is preserved relative to lexical aspects of speech. The current study questions whether dividing all errors into only two categories, morphosyntactic and lexical, is warranted, given the theoretical controversies concerning the production and representation of pronouns and closed-class words in particular. Two experiments compare the speech output of 10 individuals with Alzheimer's disease to that of 15 healthy age- and education-matched speakers. Results of the first experiment indicate that the pattern of errors in the speech of participants with mild PAD reflects an across-the-board increase in the same types of errors made by healthy older speakers, including closed-class and morphosyntactic errors. In the second task, participants produced a grammatical sentence from written stimuli consisting of a transitive verb and two nouns. Only adults with Alzheimer's disease had difficulties with this task, producing many more closed-class word errors than did healthy older adults. Three of the participants with PAD produced nearly agrammatic speech in this task. These 3 people did not differ from the rest of the PAD group in age, education, working memory, or degree of semantic impairment. Further, error rates on the two tasks were highly correlated. We conclude that morphosyntax is not preserved in the speech output of individuals with PAD, but is vulnerable to errors along with all aspects of language that must be generated by the speaker. We suggest that these results best support a model of speech production in which all words are represented by semantic and grammatical features, both of which are vulnerable to failures of activation when there is damage or noise in the system as a result of pathology, trauma, or even divided attention.

A neurocognitive perspective on language: the declarative/procedural model

What are the psychological, computational and neural underpinnings of language? Are these neurocognitive correlates dedicated to language? Do different parts of language depend on distinct neurocognitive systems? Here I address these and other issues that are crucial for our understanding of two fundamental language capacities: the memorization of words in the mental lexicon, and the rule-governed combination of words by the mental grammar. According to the declarative/procedural model, the mental lexicon depends on declarative memory and is rooted in the temporal lobe, whereas the mental grammar involves procedural memory and is rooted in the frontal cortex and basal ganglia. I argue that the declarative/procedural model provides a new framework for the study of lexicon and grammar.

Communication from individuals with advanced DAT: can it provide clues to their sense of self-awareness and well-being?

Often communication from people with advanced dementia of the Alzheimer type (DAT) is regarded as incoherent and meaningless. However, with careful listening and observation, such communication often becomes more understandable. To better understand DAT communication, the investigators designed an exploratory qualitative study to videotape and critically analyze conversations between a clinical nurse specialist and 15 subjects with DAT ranging from mild to severe. One of the findings was that, even in later stages, indications were given that subjects had self-awareness of their cognitive decline. The investigators further examined the communication of the five most cognitively impaired subjects for other indications of self-awareness and well-being. To demonstrate this premise of awareness of cognitive decline and self in the later stages of DAT, excerpts from communication received from five subjects with advanced cognitive impairment are presented.

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

OBJECTIVE

Progressive memory impairment is the primary cognitive feature of Alzheimer's disease. Systematic attention to progressive language impairment is under-appreciated. The purpose of this article is to apply the semiotic language framework to organize the disparate findings on language impairment in DAT.

METHOD

The semiotic system is hierarchical, going from simple to more complex units of language, with the hierarchical ranks of phonology, morphology, syntax, semantics. This language hierarchy is used as an organizing tool to provide a context for the discrete data on language decline in DAT. Studies relating to language impairment in DAT were identified through an exhaustive computerized search (Medline and Psych Info Database) of available literature spanning the last forty years in which 615 references were examined. Papers were selected for review if reference were made to any one or more of the language parameters of phonology, morphology, syntax, semantics, or to any components or indicators of these parameters, such as sound production, naming, grammar, sentence processing, verbal comprehension in Alzheimer patients.

RESULTS

There appears to be an overall relation between language decline and complexity of language both across and within the hierarchical ranks. There also appears to be an associated negative relation between sequence in language development and language decline. Language forms learned last in the sequence of language development are the most complex and appear to be first to deteriorate.

CONCLUSIONS

The decline of language in DAT appears to be hierarchical in nature. Further understanding of this hierarchical language decline depends in part on nosologic clarification and subtyping of DAT.

Sentence repetition and processing resources in Alzheimer's disease

Sentence processing in Alzheimer's disease (AD) has been found to be influenced by several grammatical and extragrammatical factors, including phrase structure and verb-argument relations, number of propositions/verbs, and processing resource capacity. This study examines the effects of these variables on sentence production in AD. Normal control and AD subjects were asked to repeat six types of sentences varying along the above dimensions of complexity. Subjects' processing resource capacity was measured using several verbal working memory tests. AD subjects' sentence-repetition performance was impaired compared to the normal control group. Significant effects were observed for branching direction of phrase structure, canonicity of verb-argument relations, and serial position of errors. Sentence-repetition performance significantly correlated with working memory scores. The findings are interpreted within a resource capacity theory of sentence processing.

Communication abilities of individuals with late-stage Alzheimer disease

The communication abilities of 49 individuals in the late stage of Alzheimer disease were examined in relation to other markers of late-stage Alzheimer disease (e.g., incontinence and ambulatory ability). Two existing tools used to stage severity of dementia, the Global Deterioration Scale and the Functional Assessment Stages, have represented communication abilities in individuals with late-stage Alzheimer disease to be minimal to nonexistent. The individuals in this sample showed greater communication skills and verbal output than would be predicted by these scales.

Sentence comprehension in Alzheimer's disease

We asked 22 patients with Alzheimer's disease (AD) to respond to simple probes of sentences where we manipulated grammatical factors, semantic factors, and cognitive resource demands associated with a sentence. The results demonstrated limitations in the cognitive resources needed to appreciate atypical syntactic-thematic mapping relations and difficulty processing selection restrictions associated with a verb. By comparison, comprehension in AD was not influenced by the active or passive voice of a sentence. These findings are consistent with the hypothesis that impaired sentence comprehension in AD is multifactorial in nature, including difficulty processing cognitive resource and semantic aspects of sentences.