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

Free-listing and Semantic Knowledge: A Tool for Detecting Alzheimer Disease?

BACKGROUND

Impairment in semantic knowledge contributes to Alzheimer disease (AD)-related decline. However, the particulars of the impact AD has on specific domains of knowledge remain debatable.

OBJECTIVE

To investigate the impact of AD on specific semantic categories that are integral to daily functions-living things and man-made objects.

METHOD

We administered a free-listing task (written version) to 19 individuals with AD and 15 cognitively normal older adults and assessed the task's relationship with other cognitive and functional tests in clinical use. We compared the contents of the lists of salient concepts generated by the AD and control groups.

RESULTS

Group membership (AD or control), after controlling for age, sex, formal education, and an estimate of premorbid intellectual ability, predicted the groups' performance on the free-listing task across two categories. Functional status was inversely related to performance on the free-listing task, holding demographic variables constant. Based on a comparison of the contents of the free lists that were generated by the two groups, it was possible to conclude that, in individuals with AD, conceptual knowledge central to the respective categories was well preserved, whereas the peripheral conceptual material showed evidence of degradation.

CONCLUSION

The free-listing task, which is an easy-to-administer and cost-effective tool, could aid in the preliminary detection of semantic knowledge dysfunction, revealing concepts that are better preserved and, possibly, the characterization of AD. Cognitive assessment tools that can be applied across cultures are needed, and the free-listing task has the potential to address this gap.

The Role of Working Memory and Short-Term Memory in Sentence Comprehension: A Systematic Review and Meta-Analysis in Probable Alzheimer's Disease

The role of either short-term memory (STM) or working memory (WM) in sentence comprehension is a matter of debate. Although it is commonly accepted that memory resources are necessary for sentence comprehension, there is no agreement regarding the nature of their role. The aim of this review is to investigate and synthesize assessment tools and correlation data between STM or WM and sentence comprehension in probable Alzheimer's disease (AD). To this aim, a systematic review and meta-analysis of the literature was conducted according to the PRISMA guidelines. PubMed, Web of Science, Scopus, PsycInfo, and LLBA databases were searched. Two independent authors selected peer-reviewed articles published in English and focused on the relationship between STM or WM and sentence comprehension in probable AD. A total of 11 case-control studies were included at the end of the selection process. Most studies adopted offline tasks to evaluate sentence comprehension, while a small number of authors applied online experimental tasks. The digit span forward and backward were the most employed standardized tests to evaluate phonological STM and WM, respectively. The meta-analysis results supported the association between performance on STM and WM and comprehension tasks. However, moderate heterogeneity was found, mainly due to the small number of included studies, especially for STM, and the substantial variability of the adopted tasks. Therefore, in order to clarify the specific source of language comprehension deficits, new and sophisticated experiments should be conducted using adequate material.

Clinical validity of the Italian adaptation of the Uniform Data Set Neuropsychological Test Battery (I-UDSNB) in Mild Cognitive Impairment and Alzheimer's Disease

BACKGROUND

The identification and staging of Alzheimer's Disease (AD) represent a challenge, especially in the prodromal stage of Mild Cognitive Impairment (MCI), when cognitive changes can be subtle. Worldwide efforts were dedicated to select and harmonize available neuropsychological instruments. In Italy, the Italian Network of Neuroscience and Neuro-Rehabilitation has promoted the adaptation of the Uniform Data Set Neuropsychological Test Battery (I-UDSNB), collecting normative data from 433 healthy controls (HC). Here, we aimed to explore the ability of I-UDSNB to differentiate between a) MCI and HC, b) AD and HC, c) MCI and AD.

METHODS

One hundred thirty-seven patients (65 MCI, 72 AD) diagnosed after clinical-neuropsychological assessment, and 137 HC were included. We compared the I-UDSNB scores between a) MCI and HC, b) AD and HC, c) MCI and AD, with t-tests. To identify the test(s) most capable of differentiating between groups, significant scores were entered in binary logistic and in stepwise regressions, and then in Receiver Operating Characteristic curve analyses.

RESULTS

Two episodic memory tests (Craft Story and Five Words test) differentiated MCI from HC subjects; Five Words test, Semantic Fluency (vegetables), and TMT-part B differentiated AD from, respectively, HC and MCI.

CONCLUSIONS

Our findings indicate that the I-UDSNB is a suitable tool for the harmonized and concise assessment of patients with cognitive decline, showing high sensitivity and specificity for the diagnosis of MCI and AD.

A novel speech analysis algorithm to detect cognitive impairment in a Spanish population

Objective

Early detection of cognitive impairment in the elderly is crucial for diagnosis and appropriate care. Brief, cost-effective cognitive screening instruments are needed to help identify individuals who require further evaluation. This study presents preliminary data on a new screening technology using automated voice recording analysis software in a Spanish population.

Method

Data were collected from 174 Spanish-speaking individuals clinically diagnosed as cognitively normal (CN, n = 87) or impaired (mild cognitive impairment [MCI], n = 63; all-cause dementia, n = 24). Participants were recorded performing four common language tasks (Animal fluency, alternating fluency [sports and fruits], phonemic "F" fluency, and Cookie Theft Description). Recordings were processed via text-transcription and digital-signal processing techniques to capture neuropsychological variables and audio characteristics. A training sample of 122 subjects with similar demographics across groups was used to develop an algorithm to detect cognitive impairment. Speech and task features were used to develop five independent machine learning (ML) models to compute scores between 0 and 1, and a final algorithm was constructed using repeated cross-validation. A socio-demographically balanced subset of 52 participants was used to test the algorithm. Analysis of covariance (ANCOVA), covarying for demographic characteristics, was used to predict logistically-transformed algorithm scores.

Results

Mean logit algorithm scores were significantly different across groups in the testing sample (p < 0.01). Comparisons of CN with impaired (MCI + dementia) and MCI groups using the final algorithm resulted in an AUC of 0.93/0.90, with overall accuracy of 88.4%/87.5%, sensitivity of 87.5/83.3, and specificity of 89.2/89.2, respectively.

Conclusion

Findings provide initial support for the utility of this automated speech analysis algorithm as a screening tool for cognitive impairment in Spanish speakers. Additional study is needed to validate this technology in larger and more diverse clinical populations.

Electrophysiological alterations during action semantic processing in Parkinson's disease

Assessments of action semantics consistently reveal markers of Parkinson's disease (PD). However, neurophysiological signatures of the domain remain under-examined in this population, especially under conditions that allow patients to process stimuli without stringent time constraints. Here we assessed event-related potentials and time-frequency modulations in healthy individuals (HPs) and PD patients during a delayed-response semantic judgment task involving related and unrelated action-picture pairs. Both groups had shorter response times for related than for unrelated trials, but they exhibited discrepant electrophysiological patterns. HPs presented significantly greater N400 amplitudes as well as theta enhancement and mu desynchronization for unrelated relative to related trials. Conversely, N400 and theta modulations were abolished in the patients, who further exhibited a contralateralized cluster in the mu range. None of these patterns were associated with the participants' cognitive status. Our results suggest that PD involves multidimensional neurophysiological disruptions during action-concept processing, even under task conditions that elicit canonical behavioral effects. New constraints thus emerge for translational neurocognitive models of the disease.

Electroencephalography-based classification of Alzheimer's disease spectrum during computer-based cognitive testing

Alzheimer's disease (AD) is a progressive disease leading to cognitive decline, and to prevent it, researchers seek to diagnose mild cognitive impairment (MCI) early. Particularly, non-amnestic MCI (naMCI) is often mistaken for normal aging as the representative symptom of AD, memory decline, is absent. Subjective cognitive decline (SCD), an intermediate step between normal aging and MCI, is crucial for prediction or early detection of MCI, which determines the presence of AD spectrum pathology. We developed a computer-based cognitive task to classify the presence or absence of AD pathology and stage within the AD spectrum, and attempted to perform multi-stage classification through electroencephalography (EEG) during resting and memory encoding state. The resting and memory-encoding states of 58 patients (20 with SCD, 10 with naMCI, 18 with aMCI, and 10 with AD) were measured and classified into four groups. We extracted features that could reflect the phase, spectral, and temporal characteristics of the resting and memory-encoding states. For the classification, we compared nine machine learning models and three deep learning models using Leave-one-subject-out strategy. Significant correlations were found between the existing neurophysiological test scores and performance of our computer-based cognitive task for all cognitive domains. In all models used, the memory-encoding states realized a higher classification performance than resting states. The best model for the 4-class classification was cKNN. The highest accuracy using resting state data was 67.24%, while it was 93.10% using memory encoding state data. This study involving participants with SCD, naMCI, aMCI, and AD focused on early Alzheimer's diagnosis. The research used EEG data during resting and memory encoding states to classify these groups, demonstrating the significance of cognitive process-related brain waves for diagnosis. The computer-based cognitive task introduced in the study offers a time-efficient alternative to traditional neuropsychological tests, showing a strong correlation with their results and serving as a valuable tool to assess cognitive impairment with reduced bias.

A preliminary investigation on core lexicon analysis in dementia of the Alzheimer's type

BACKGROUND

Core lexicon (CL) analysis is a time efficient and possibly reliable measure that captures discourse production abilities. For people with aphasia, CL scores have demonstrated correlations with aphasia severity, as well as other discourse and linguistic measures. It was also found to be clinician-friendly and clinically sensitive enough to capture longitudinal changes in aphasia. To our knowledge, CL has never been investigated in individuals with neurologically progressive disease.

AIMS

As a preliminary investigation, we sought to investigate (1) whether CL scores correlate with dementia severity, (2) whether CL scores correlate with measures of discourse quality, and (3) whether CL scores correlate with other measures of lexical/semantic access.

METHODS & PROCEDURES

Twelve participants with a cognitive impairment associated with dementia of the Alzheimer's type (DAT) completed several measures of language and cognitive ability, as well as provide a language sample from the wordless picture book, Picnic.

RESULTS & CONCLUSION

Results are informative, as they provide insight into characteristics of CL and provide support for potential use of CL in individuals with neurologically progressive disease. The results indicated that CL scores do correlate with dementia severity and several measures of language ability, indicating they may provide a useful measure of language abilities in DAT, but more research is needed.

WHAT THIS PAPER ADDS

What is already known on the subject Core lexicon (CL) analysis is an assessment measure of discourse ability, most closely related to informativeness or productivity, used in aphasiology that is easier to use and less time consuming than previous measures of informativeness, such as correct information units or type-token ratio (TTR). For people with aphasia, CL analysis correlates with aphasia severity, measures of informativeness, as well as other measures of discourse quality. It has also been shown to be faster and more reliable between scorers than other informativeness measures. What this study adds Core lexicon analysis is a new simple and online method for assessing the informativeness of a discourse sample without the need to record or transcribe the language sample. CL is receiving a lot of attention in aphasia, correlating with everything from aphasia severity to measures of productivity and lexical access, as well as measures of informativeness. Unfortunately, no one has investigated CL analysis in dementia. The study demonstrates the first evidence that CL analysis may be a useful measure for determining dementia severity and language quality in people with dementia. What are the clinical implications of this work? Core lexicon analysis may provide clinicians and researchers with an easy method for assessing the discourse of people with a cognitive impairment associated with dementia of the Alzheimer's type. This will improve initial assessment, as well as improve ongoing language assessment that may provide clues into their functional ability to communicate effectively.

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.

The Role of Non-coding RNAs in Alzheimer's Disease: Pathogenesis, Novel Biomarkers, and Potential Therapeutic Targets

Long non-coding RNAs (IncRNAs) are regulatory RNA transcripts that have recently been associated with the onset of many neurodegenerative illnesses, including Alzheimer's disease (AD). Several IncRNAs have been found to be associated with AD pathophysiology, each with a distinct mechanism. In this review, we focused on the role of IncRNAs in the pathogenesis of AD and their potential as novel biomarkers and therapeutic targets. Searching for relevant articles was done using the PubMed and Cochrane library databases. Studies had to be published in full text in English in order to be considered. Some IncRNAs were found to be upregulated, while others were downregulated. Dysregulation of IncRNAs expression may contribute to AD pathogenesis. Their effects manifest as the synthesis of beta-amyloid (Aβ) plaques increases, thereby altering neuronal plasticity, inducing inflammation, and promoting apoptosis. Despite the need for more investigations, IncRNAs could potentially increase the sensitivity of early detection of AD. Until now, there has been no effective treatment for AD. Hence, InRNAs are promising molecules and may serve as potential therapeutic targets. Although several dysregulated AD-associated lncRNAs have been discovered, the functional characterization of most lncRNAs is still lacking.

Factor structure and clinical applicability of new semantic tasks in Alzheimer's disease and aphasia

Semantic tasks are frequently used when examining language functions in patients with acquired disorders such as Alzheimer's disease (AD) and aphasia. Little is known about the possible covariation between different types of tasks or their factor structure in healthy adults. Additionally, few studies have examined semantic task performances in different patient groups. The aims of this data-driven study were to examine the factor structure in a wide range of semantic tasks in healthy older adults, the possible differences in factor variables between healthy controls, patients with AD and patients with stroke aphasia, as well as the clinical applicability of tasks in differentiating the two patient groups from controls. Participants included 59 healthy older adults, 13 patients with AD and 14 patients with aphasia. The results indicated a four-factor solution for the semantic task variables: (1) the Semantic association factor, (2) the Time factor, (3) the Verbal factor and (4) the Synonym factor. The Verbal factor was the only distinguishing factor between the two patient groups. Three factors reliably discriminated between the controls and the AD patients, and the Verbal factor reliably discriminated between the controls and the aphasia patients. In addition, a few single task variables showed outstanding discrimination for both patient groups. This study supports the notions of semantic tasks tapping into more than one cognitive subcomponent and a more general semantic impairment in AD than in aphasia. In clinical assessment, choosing appropriate semantic tasks is crucial in order to reliably detect the characteristics of the impairment.

Speech changes in old age: Methodological considerations for speech-based discrimination of healthy ageing and Alzheimer's disease

BACKGROUND

Recent evidence suggests that speech substantially changes in ageing. As a complex neurophysiological process, it can accurately reflect changes in the motor and cognitive systems underpinning human speech. Since healthy ageing is not always easily discriminable from early stages of dementia based on cognitive and behavioural hallmarks, speech is explored as a preclinical biomarker of pathological itineraries in old age. A greater and more specific impairment of neuromuscular activation, as well as  a specific cognitive and linguistic impairment in dementia, unchain discriminating changes in speech. Yet, there is no consensus on such discriminatory speech parameters, neither on how they should be elicited and assessed.

AIMS

To provide a state-of-the-art on speech parameters that allow for early discrimination between healthy and pathological ageing; the aetiology of these parameters; the effect of the type of experimental stimuli on speech elicitation and the predictive power of different speech parameters; and the most promising methods for speech analysis and their clinical implications.

METHODS & PROCEDURES

A scoping review methodology is used in accordance with the PRISMA model. Following a systematic search of PubMed, PsycINFO and CINAHL, 24 studies are included and analysed in the review.

MAIN CONTRIBUTION

The results of this review yield three key questions for the clinical assessment of speech in ageing. First, acoustic and temporal parameters are more sensitive to changes in pathological ageing and, of these two, temporal variables are more affected by cognitive impairment. Second, different types of stimuli can trigger speech parameters with different degree of accuracy for the discrimination of clinical groups. Tasks with higher cognitive load are more precise in eliciting higher levels of accuracy. Finally, automatic speech analysis for the discrimination of healthy and pathological ageing should be improved for both research and clinical practice.

CONCLUSIONS & IMPLICATIONS

Speech analysis is a promising non-invasive tool for the preclinical screening of healthy and pathological ageing. The main current challenges of speech analysis in ageing are the automatization of its clinical assessment and the consideration of the speaker's cognitive background during evaluation.

WHAT THIS PAPER ADDS

What is already known on the subject Societal aging  goes hand in hand with the rising incidence of ageing-related neurodegenerations, mainly Alzheimer's disease (AD). This is particularly noteworthy in countries with longer life expectancies. Healthy ageing and early stages of AD share a set of cognitive and behavioural characteristics. Since there is no cure for dementias, developing methods for accurate discrimination of healthy ageing and early AD is currently a priority. Speech has been described as one of the most significantly impaired features in AD. Neuropathological alterations in motor and cognitive systems would underlie specific speech impairment in dementia. Since speech can be evaluated quickly, non-invasively and inexpensively, its value for the clinical assessment of ageing itineraries may be particularly high. What this paper adds to existing knowledge Theoretical and experimental advances in the assessment of speech as a marker of AD have developed rapidly over the last decade. Yet, they are not always known to clinicians. Furthermore, there is a need to provide an updated state-of-the-art on which speech features are discriminatory to AD, how they can be assessed, what kind of results they can yield, and how such results should be interpreted. This article provides an updated overview of speech profiling, methods of speech measurement and analysis, and the clinical power of speech assessment for early discrimination of AD as the most common cause of dementia. What are the potential or actual clinical implications of this work? This article provides an overview of the predictive potential of different speech parameters in relation to AD cognitive impairment. In addition, it discusses the effect that the cognitive state, the type of elicitation task and the type of assessment method may have on the results of the speech-based analysis in ageing.

Application of the Semantic Fluency Test in the Screening of Mandarin-Chinese-Speaking Older Adults with Mild Dementia of the Alzheimer Type

Semantic fluency tests have been widely used as a screening test for dementia of Alzheimer type. However, few studies have explored the application of semantic fluency tests in Mandarin Chinese speakers. This study aimed to explore the feasibility of using different semantic fluency test categories to distinguish between older adults without cognitive impairments and those with dementia of Alzheimer type in Taiwan. A total of 58 healthy older adults and 54 individuals with dementia of Alzheimer type were recruited. Semantic categories of "animals", "fruits", "vegetables", "birds", "means of transportations" and "musical instruments" were administered to participants. The scores from two groups of participants for each category were analyzed. Significant differences in the test scores of each category between two groups of participants were found. The results also revealed that the variables related to whether the participant had dementia, gender, age, and years of schooling significantly influenced the semantic fluency scores for each category. Among all the demographic characteristic of participants, the diagnosis of dementia was the most determining factor. Furthermore, this study proposed optimal cutoff points and calculated the AUC for various test durations (i.e., 30 s, 45 s and 60 s) and semantic categories in the semantic fluency test, which may serve as a reference that would help clinical personnel distinguish between older adults without cognitive impairments and those with dementia of Alzheimer type in Taiwan.

Language dysfunction correlates with cognitive impairments in older adults without dementia mediated by amyloid pathology

Background

Previous studies have explored the application of non-invasive biomarkers of language dysfunction for the early detection of Alzheimer's disease (AD). However, language dysfunction over time may be quite heterogeneous within different diagnostic groups.

Method

Patient demographics and clinical data were retrieved from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database for the participants without dementia who had measures of cerebrospinal fluid (CSF) biomarkers and language dysfunction. We analyzed the effect of longitudinal neuropathological and clinical correlates in the pathological process of semantic fluency and confrontation naming. The mediation effects of AD biomarkers were also explored by the mediation analysis.

Result

There were 272 subjects without dementia included in this analysis. Higher rates of decline in semantic fluency and confrontation naming were associated with a higher risk of progression to MCI or AD, and a greater decline in cognitive abilities. Moreover, the rate of change in semantic fluency was significantly associated with Aβ deposition, while confrontation naming was significantly associated with both amyloidosis and tau burden. Mediation analyses revealed that both confrontation naming and semantic fluency were partially mediated by the Aβ aggregation.

Conclusion

In conclusion, the changes in language dysfunction may partly stem from the Aβ deposition, while confrontation naming can also partly originate from the increase in tau burden. Therefore, this study sheds light on how language dysfunction is partly constitutive of mild cognitive impairment and dementia and therefore is an important clinical predictor.

The Effects of Transcutaneous Vagus Nerve Stimulation on Functional Connectivity Within Semantic and Hippocampal Networks in Mild Cognitive Impairment

Better treatments are needed to improve cognition and brain health in people with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Transcutaneous vagus nerve stimulation (tVNS) may impact brain networks relevant to AD through multiple mechanisms including, but not limited to, projection to the locus coeruleus, the brain's primary source of norepinephrine, and reduction in inflammation. Neuropathological data suggest that the locus coeruleus may be an early site of tau pathology in AD. Thus, tVNS may modify the activity of networks that are impaired and progressively deteriorate in patients with MCI and AD. Fifty patients with MCI (28 women) confirmed via diagnostic consensus conference prior to MRI (sources of info: Montreal Cognitive Assessment Test (MOCA), Clinical Dementia Rating scale (CDR), Functional Activities Questionnaire (FAQ), Hopkins Verbal Learning Test - Revised (HVLT-R) and medical record review) underwent resting state functional magnetic resonance imaging (fMRI) on a Siemens 3 T scanner during tVNS (left tragus, n = 25) or sham control conditions (left ear lobe, n = 25). During unilateral left tVNS, compared with ear lobe stimulation, patients with MCI showed alterations in functional connectivity between regions of the brain that are important in semantic and salience functions including regions of the temporal and parietal lobes. Furthermore, connectivity from hippocampi to several cortical and subcortical clusters of ROIs also demonstrated change with tVNS compared with ear lobe stimulation. In conclusion, tVNS modified the activity of brain networks in which disruption correlates with deterioration in AD. These findings suggest afferent target engagement of tVNS, which carries implications for the development of noninvasive therapeutic intervention in the MCI population.

Lower semantic fluency scores and a phonemic-over-semantic advantage predict abnormal CSF P-tau181 levels in Aβ + patients within the Alzheimer's disease clinical spectrum

BACKGROUND

The present study aimed to determine whether patients with mild cognitive impairment (MCI) and dementia due to Alzheimer's disease (AD), semantic verbal fluency (SVF), and the semantic-phonemic discrepancy (SPD) could predict abnormal cerebrospinal fluid (CSF) phosphorylated tau (P-tau₁₈₁) and total tau (T-tau) levels.

METHODS

Phonemic verbal fluency (PVF) and SVF scores of N = 116 Aβ-positive patients with either MCI due to AD (N = 39) or probable AD dementia (ADD; N = 77) were retrospectively collected. The SPD was computed by subtracting PVF scores from SVF ones (positive and negative values corresponding to a semantic and phonemic advantage, respectively). Patients were cognitively phenotyped via a thorough test battery and profiled according to the amyloidosis/tauopathy/neurodegeneration (ATN) framework via CSF analyses. Two separate sets of logistic regressions were run to predict normal vs. abnormal P-tau₁₈₁ and T-tau levels by encompassing as predictors SVF + PVF and SPD and covarying for demographic, disease-related features, and cognitive profile.

RESULTS

Lower SVF, but not PVF, scores, as well as a greater phonemic advantage (i.e., negative SPD values), predicted abnormal CSF P-tau₁₈₁ levels (p ≤ .01). Moreover, lower SVF scores were selectively predictive of abnormal CSF T-tau levels too (p = .016), while the SPD was not.

DISCUSSION

SVF and the SPD are able to predict tauopathy across the AD spectrum, thus supporting their status of valid, and sufficiently specific, cognitive markers of AD.

Development of a simple screening tool for determining cognitive status in Alzheimer's disease

Cognitive screening is often a first step to document cognitive status of patients suspected having Alzheimer's disease (AD). Unfortunately, screening neuropsychological tests are often insensitivity in the detection. The goal of this study was to develop a simple and sensitive screening neuropsychological test to facilitate early detection of AD. This study recruited 761 elderly individuals suspected of having AD and presenting various cognitive statuses (mean age: 77.69 ± 8.45 years; proportion of females: 65%; cognitively unimpaired, CU, n = 133; mild cognitive impairment, MCI, n = 231; dementia of Alzheimer's type, DAT, n = 397). This study developed a novel screening neuropsychological test incorporating assessments of the core memory deficits typical of early AD and an interview on memory function with an informant. The proposed History-based Artificial Intelligence-Show Chwan Assessment of Cognition (HAI-SAC) was assessed in terms of psychometric properties, test time, and discriminative ability. The results were compared with those obtained using other common screening tests, including Cognitive Abilities Screening Instrument (CASI), Montreal Cognitive Assessment (MoCA), and an extracted Mini-Mental State Examination score from CASI. HAI-SAC demonstrated acceptable internal consistency. Factor analysis revealed two factors: memory (semantic and contextual) and cognition-related information from informants. The assessment performance of HAI-SAC was strongly correlated with that of the common screening neuropsychological tests addressed in this study. HAI-SAC outperformed the other tests in differentiating CU individuals from patients with MCI (sensitivity: 0.87; specificity: 0.58; area under the curve [AUC]: 0.78) or DAT (sensitivity: 0.99; specificity: 0.89; AUC: 0.98). Performance of HAI-SAC on differentiating MCI from DAT was on par with performances of other tests (sensitivity: 0.78; specificity: 0.84; AUC: 0.87), while the test time was less than one quarter that of CASI and half that of MoCA. HAI-SAC is psychometrically sound, cost-effective, and sensitive in discriminating the cognitive status of AD.

Assessing Longitudinal Cognitive Change in Mild Cognitive Impairment Using Estimated Standardized Regression-Based Formulas

BACKGROUND

Cognitive change in mild cognitive impairment (MCI), a likely prodrome to Alzheimer's disease, can be tracked with repeated neuropsychological assessments, but there has been little work quantifying these changes over time. Cognitive change can be statistically examined using standardized regression-based (SRB) formulas, which yield a z-score indicating amount of change compared to a normative group.

OBJECTIVE

To use SRB z-scores to quantify cognitive change in a sample of patients classified as MCI at baseline, and to compare cognitive change in those who remained MCI on follow-up (MCI-Stable) and those who progressed to dementia (MCI-Decline).

METHODS

Using 283 MCI patients from a cognitive disorders clinic who were re-assessed after approximately one- and one-half years, SRB z-scores were calculated for each test in a comprehensive neuropsychological battery for each participant.

RESULTS

There was a significant decline between timepoints across all cognitive tests, with the greatest amount of decline on tests of learning and memory. Group differences were seen on nearly all cognitive tests, with the MCI-Decline group showing more decline (i.e., significantly larger and negative z-scores) than the MCI-Stable participants. Notable cognitive decline was also observed in the MCI-Stable group, with z-scores ranging from -0.01 - -2.24 compared to normative data.

CONCLUSION

This study highlights the amount of cognitive decline that occurs in MCI, including for those who remain "stable" and those who progress to dementia. It also demonstrates the value of the SRB method in more clearly quantifying cognitive decline, which may help identify individuals most vulnerable to MCI progression.

Phonological and Semantic Fluency in Alzheimer's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Semantic and Phonological fluency (SF and PF) are routinely evaluated in patients with Alzheimer's disease (AD). There are disagreements in the literature regarding which fluency task is more affected while developing AD. Most studies focus on SF assessment, given its connection with the temporoparietal amnesic system. PF is less reported, it is related to working memory, which is also impaired in probable and diagnosed AD. Differentiating between performance on these tasks might be informative in early AD diagnosis, providing an accurate linguistic profile.

OBJECTIVE

Compare SF and PF performance in healthy volunteers, volunteers with probable AD, and patients with AD diagnosis, considering the heterogeneity of age, gender, and educational level variables.

METHODS

A total of 8 studies were included for meta-analysis, reaching a sample size of 1,270 individuals (568 patients diagnosed with AD, 340 with probable AD diagnosis, and 362 healthy volunteers).

RESULTS

The three groups consistently performed better on SF than PF. When progressing to a diagnosis of AD, we observed a significant difference in SF and PF performance across our 3 groups of interest (p = 0.04). The age variable explained a proportion of this difference in task performance across the groups, and as age increases, both tasks equally worsen.

CONCLUSION

The performance of SF and PF might play a differential role in early AD diagnosis. These tasks rely on partially different neural bases of language processing. They are thus worth exploring independently in diagnosing normal aging and its transition to pathological stages, including probable and diagnosed AD.

A Review on Music Interventions for Frontotemporal Aphasia and a Proposal for Alternative Treatments

Frontotemporal dementia (FTD) is a rare neurodegenerative disease, characterized by behavioral and language impairments. Primary progressive aphasia (PPA) is the linguistic variant of this heterogeneous disorder. To date, there is a lack of consensus about which interventions are effective in these patients. However, several studies show that music-based interventions are beneficial in neurological diseases. This study aims, primarily, to establish the state of the art of music-based interventions designed for PPA due to FTD and, secondarily, to inform the planning of PPA-dedicated future interventions for Italian neurological institutions. The first aim is fulfilled by a review which critically screens the neurological studies examining the effects of music- and/or rhythm-based interventions, especially, on language rehabilitation in aphasic FTD. We found that only two papers fulfilled our criteria and concerned specifically aphasic patients due to FTD. Of those, one paper reported a study conducted in an Italian institution. Most of the reviewed studies focused, instead, on aphasia in post-stroke patients. The results of our review invite further studies to investigate the role of music as a valuable support in the therapy for neurodegenerative patients with language problems and in particular to PPA due to FTD. Moreover, based on this initial work, we can delineate new music-based interventions dedicated to PPA for Italian institutions.

Identifying neurocognitive disorder using vector representation of free conversation

In recent years, studies on the use of natural language processing (NLP) approaches to identify dementia have been reported. Most of these studies used picture description tasks or other similar tasks to encourage spontaneous speech, but the use of free conversation without requiring a task might be easier to perform in a clinical setting. Moreover, free conversation is unlikely to induce a learning effect. Therefore, the purpose of this study was to develop a machine learning model to discriminate subjects with and without dementia by extracting features from unstructured free conversation data using NLP. We recruited patients who visited a specialized outpatient clinic for dementia and healthy volunteers. Participants’ conversation was transcribed and the text data was decomposed from natural sentences into morphemes by performing a morphological analysis using NLP, and then converted into real-valued vectors that were used as features for machine learning. A total of 432 datasets were used, and the resulting machine learning model classified the data for dementia and non-dementia subjects with an accuracy of 0.900, sensitivity of 0.881, and a specificity of 0.916. Using sentence vector information, it was possible to develop a machine-learning algorithm capable of discriminating dementia from non-dementia subjects with a high accuracy based on free conversation.

Learning From Mistakes: Cognitive and Metabolic Correlates of Errors on Picture Naming in the Alzheimer’s Disease Spectrum

Background: Analysis of subtypes of picture naming errors produced by patients with Alzheimer’s disease (AD) have seldom been investigated yet may clarify the cognitive and neural underpinnings of naming in the AD spectrum. Objective: To elucidate the neurocognitive bases of picture naming in AD through a qualitative analysis of errors. Methods: Over 1000 naming errors produced by 70 patients with amnestic, visuospatial, linguistic, or frontal AD were correlated with general cognitive tests and with distribution of hypometabolism on FDG-PET. Results: Principal component analysis identified 1) a Visual processing factor clustering visuospatial tests and unrecognized stimuli, pure visual errors and visual-semantic errors, associated with right parieto-occipital hypometabolism; 2) a Concept-Lemma factor grouping language tests and anomias, circumlocutions, superordinates, and coordinates, correlated with left basal temporal hypometabolism; 3) a Lemma-Phonology factor including the digit span and phonological errors, linked with left temporo-parietal hypometabolism. Regression of brain metabolism on individual errors showed that errors due to impairment of basic and higher-order processing of object visual attributes or of their interaction with semantics, were related with bilateral occipital and left occipito-temporal dysfunction. Omissions and superordinates were linked to degradation of broad and basic concepts in the left basal temporal cortex. Semantic-lexical errors derived from faulty semantically- and phonologically-driven lexical retrieval in the left superior and middle temporal gyri. Generation of nonwords was underpinned by of phonological impairment within the left inferior parietal cortex. Conclusion: Analysis of individual naming errors allowed to outline a comprehensive anatomo-functional model of picture naming in classical and atypical AD.

Detecting Alzheimer's Disease Using Natural Language Processing of Referential Communication Task Transcripts

BACKGROUND

People with Alzheimer's disease (AD) often demonstrate difficulties in discourse production. Referential communication tasks (RCTs) are used to examine a speaker's capability to select and verbally code the characteristics of an object in interactive conversation.

OBJECTIVE

In this study, we used contextualized word representations from Natural language processing (NLP) to evaluate how well RCTs are able to distinguish between people with AD and cognitively healthy older adults.

METHODS

We adapted machine learning techniques to analyze manually transcribed speech transcripts in an RCT from 28 older adults, including 12 with AD and 16 cognitively healthy older adults. Two approaches were applied to classify these speech transcript samples: 1) using clinically relevant linguistic features, 2) using machine learned representations derived by a state-of-art pretrained NLP transfer learning model, Bidirectional Encoder Representation from Transformer (BERT) based classification model.

RESULTS

The results demonstrated the superior performance of AD detection using a designed transfer learning NLP algorithm. Moreover, the analysis showed that transcripts of a single image yielded high accuracies in AD detection.

CONCLUSION

The results indicated that RCT may be useful as a diagnostic tool for AD, and that the task can be simplified to a subset of images without significant sacrifice to diagnostic accuracy, which can make RCT an easier and more practical tool for AD diagnosis. The results also demonstrate the potential of RCT as a tool to better understand cognitive deficits from the perspective of discourse production in people with AD.

Neuropsychological assessment of patients with alzheimer's Disease in the presence or absence of spouses

A common question in the neuropsychological testing of patients with Alzheimer's Disease is whether or not patients should be tested in the presence of their spouses. We addressed this issue by assessing the neuropsychological performances of Alzheimer's Disease patients in the presence or absence of spouses. Results showed no significant differences between patients' performances in the presence or absence of spouses on tests assessing general cognitive abilities, episodic memory, working memory, inhibition and flexibility. No significant differences were observed regarding either anxiety or depression in patients when tested alone, compared to when spouses were attending. However, patients demonstrated higher verbal fluency when tested alone compared to when spouses attended. Clinicians may carry out neuropsychological assessment in the presence or absence of spouses, except when assessing verbal fluency. In such cases, clinicians should privilege testing patients alone or, if spouses attend the test, take into account this variable when interpreting patients' performances.

The temporal lobe in typical and atypical Alzheimer disease

Alzheimer disease (AD) is defined neuropathologically by abnormal extra-cellular β-amyloid plaques combined with intraneuronal tau aggregation. Patients sharing the same neuropathological features but presenting different clinical manifestations and evolutions have led to the notion of AD spectrum. This spectrum encompasses typical and atypical forms of AD. For all of them, specific parts of the temporal lobes, as well as their structural and functional connections with other brain regions, are affected. In typical amnestic late-onset Alzheimer's disease (>65 years old; LOAD), tau pathology gradually spreads to the brain from the medial temporal lobe (MTL). MTL is an inhomogeneous structure consisting of several subregions densely connected to each other and to other cortical and subcortical brain regions. These regions play a crucial role in the storage of information in episodic memory. In less common early-onset AD (<65 years old; EOAD), a large proportion of patients presents atypical clinical manifestations, in which memory impairment is not inaugural and predominant. Instead, these patients have predominant and/or isolated deficits in language, visuospatial, motor, or executive/behavioral functions. In atypical variants, brain damage is mainly centered on the posterior regions, with relative sparing of the MTL. However, the temporal lobe also appears to be variably and specifically damaged in some subtypes of EOAD. For example, the left superior temporal gyrus is the core of brain damage in the language variant, as well as the ventral regions of the temporal lobe play an important role in the clinic of the visual variant.

Abnormal cerebrospinal fluid levels of amyloid and tau are associated with cognitive decline over time in cognitively normal older adults: A monozygotic twin study

Introduction

The contribution of genetic and environmental factors to the relation between cerebrospinal fluid (CSF) biomarkers and cognitive decline in preclinical Alzheimer's disease remains unclear. We studied this in initially cognitively normal monozygotic twins.

Methods

We included 122 cognitively normal monozygotic twins (51 pairs) with a follow‐up of 4.3 ± 0.4 years. We first tested associations of baseline CSF Aβ1‐42/1‐40 ratio, total tau (t‐tau), and 181‐phosphorylated‐tau (p‐tau) status with subsequent cognitive decline using linear mixed models, and then performed twin specific analyses.

Results

Baseline abnormal amyloid‐β and tau CSF markers predicted steeper decline on memory (p ≤ .003) and language (p ≤ 0.04). Amyloid‐β and p‐tau markers in one twin predicted decline in memory in the co‐twin and tau markers in one twin predicted decline in language in the co‐twin (r range ‐0.26,0.39; p’s ≤ .02).

Discussion

These results suggest that memory and language decline are early features of AD that are in part determined by the same genetic factors that influence amyloid‐β and tau regulation.

APOE, TOMM40, and sex interactions on neural network connectivity

The Apolipoprotein E ε4 (APOE ε4) haplotype is the strongest genetic risk factor for late-onset Alzheimer's disease (AD). The Translocase of Outer Mitochondrial Membrane-40 (TOMM40) gene maintains cellular bioenergetics, which is disrupted in AD. TOMM40 rs2075650 ('650) G versus A carriage is consistently related to neural and cognitive outcomes, but it is unclear if and how it interacts with APOE. We examined 21 orthogonal neural networks among 8,222 middle-aged to aged participants in the UK Biobank cohort. ANOVA and multiple linear regression tested main effects and interactions with APOE and TOMM40 '650 genotypes, and if age and sex acted as moderators. APOE ε4 was associated with less strength in multiple networks, while '650 G versus A carriage was related to more language comprehension network strength. In APOE ε4 carriers, '650 G-carriage led to less network strength with increasing age, while in non-G-carriers this was only seen in women but not men. TOMM40 may shift what happens to network activity in aging APOE ε4 carriers depending on sex.

The effect of cognitive stimulation on the progression of cognitive impairment in subjects with Alzheimer's disease

The overall objective of this study was to examine the impact of a cognitive stimulation intervention model on subjects with mild-moderate Alzheimer's disease (AD) using a comprehensive neuropsychological assessment. The stimulation intervention consisted of carrying out cognitive activities with a small group of participants during a 6-month period. The program designed included 3 weekly 1-h sessions that always targeted the same two functions using different tasks. The pretest-posttest study design was carried out on two groups of patients: the control group, and the experimental group receiving the intervention. The sample consisted of 20 patients, aged between 66 and 89 years (M = 81.90; SD = 5.476), attending a day care center. Cognitive stimulation was conducted on the subjects in the experimental group three times a week for 6 months. The statistical analysis performed was a repeated measures ANOVA, with the groups (intervention vs. no intervention) being the between-subject factor. The aim was to detect interaction between two different factors. Interaction was found between the scores obtained for comprehension (F(1, 18) = 4.662, d = -0.963, p-value = 0.045), visual reproduction copy (F(1, 18) = 7.106, d = -1.07; p-value = 0.016) and word list recognition (F(1, 18) = 5.345; d = -1.038; p-value = 0.003). We can conclude that this model of intervention maintained the cognitive performance of patients with mild-moderate AD with respect to reasoning, constructive praxis and the recognition of word lists, while the control group showed a deterioration in these functions within 6-month period.

Macro-event recognition in healthy ageing, Alzheimer's disease, and mild cognitive impairment

Event perception and cognition is integral to our everyday experience and functional ability. A commonly reported complaint in Alzheimer's disease (AD) is the inability to follow narratives - be it textual, conversational, video, or pictures. This phenomenon has received little systematic research so far. In the current study, we developed a novel paradigm to examine macro-event recognition in individuals with AD in the early stage and its preceding stage of mild cognitive impairment (MCI) in comparison with cognitively healthy older adults, using pictures depicting events. In Experiment 1, we examined participants' ability to integrate pictorially depicted sub-events into macro-events. The pictures were presented in a scrambled order, and participants were expected to arrange them in the temporally and causally appropriate sequence, as dictated by the macro-event schema. Additionally, we investigated the effect of cueing the appropriate event schema by providing a word cue (verb). In Experiment 2, macro-event recognition was examined again using a cognitively less taxing paradigm, where pictures depicting sub-events were presented in correct order, but staggered, and recognition speed was measured. We observed significant deficits in the AD and MCI groups' performance compared with the cognitively healthy older adults, across both experiments, suggesting event perception and cognition is impaired early in the course of AD. There was no effect of cueing on the performance of any of the groups. The theoretical and clinical implications of these findings are discussed.

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.

Cross-sectional associations of tau protein biomarkers with semantic and episodic memory in older adults without dementia: A systematic review and meta-analysis

Pathological tau is suggested to play a role in cognitive deterioration in the preclinical phase of Alzheimer's disease. We investigated cross-sectional associations of tau burden with episodic and semantic memory performance in older adults without dementia. A systematic search in MEDLINE (via PubMed), PsychINFO, and Embase resulted in 24 eligible studies for meta-analysis. Tau burden was assessed using CSF, PET, or histopathological measures. All studies evaluated associations of tau with episodic memory: weighted effect sizes were -0.46 (95 % CI [-0.73; -0.20], p < .001) for episodic composite scores, -0.19 ([-0.36; -0.03], p = .024) for delayed word list recall, and -0.05 ([-0.14; 0.04], p = .257) for logical memory. Fourteen studies evaluated associations of tau with semantic memory: weighted effect sizes were -0.28 ([-0.52; -0.04], p = .023) for semantic composite scores, -0.06 ([-0.16; 0.03], p = .194) for semantic fluency, and 0.06 ([-0.06; 0.18], p = .319) for picture naming. Our findings indicate that tau burden related to both episodic and semantic memory impairment in older individuals without a diagnosis of mild cognitive impairment or manifest dementia, with episodic composite scores showing the strongest association with tau burden. Future potential lies in developing more sensitive scores to detect this subtle cognitive impairment, which could contribute to early identification of individuals in the preclinical phase of Alzheimer's disease, thereby improving early diagnosis and timely intervention.

Language in Behavioral Variant Frontotemporal Dementia: Another Stone to Be Turned in Latin America

Beyond canonical deficits in social cognition and interpersonal conduct, behavioral variant frontotemporal dementia (bvFTD) involves language difficulties in a substantial proportion of cases. However, since most evidence comes from high-income countries, the scope and relevance of language deficits in Latin American bvFTD samples remain poorly understood. As a first step toward reversing this scenario, we review studies reporting language measures in Latin American bvFTD cohorts relative to other groups. We identified 24 papers meeting systematic criteria, mainly targeting phonemic and semantic fluency, naming, semantic processing, and comprehension skills. The evidence shows widespread impairments in these domains, often related to overall cognitive disturbances. Some of these deficits may be as severe as in other diseases where they are more widely acknowledged, such as Alzheimer's disease. Considering the prevalence and informativeness of language deficits in bvFTD patients from other world regions, the need arises for more systematic research in Latin America, ideally spanning multiple domains, in diverse languages and dialects, with validated batteries. We outline key challenges and pathways of progress in this direction, laying the ground for a new regional research agenda on the disorder.

Validity of the Montreal Cognitive Assessment (MoCA) Index Scores: a Comparison with the Cognitive Domain Scores of the Seoul Neuropsychological Screening Battery (SNSB)

Background and Purpose

A new approach was proposed to score the Montreal Cognitive Assessment (MoCA) index scores for 6 cognitive domains: orientation (OIS), attention (AIS), language (LIS), visuospatial function (VIS), memory (MIS), and executive function (EIS). This study investigated whether the MoCA index scores represent the functions of each cognitive domain by examining the correlations with the corresponding cognitive domain scores derived from conventional neuropsychological tests included in the Seoul Neuropsychological Screening Battery, 2nd Edition (SNSB-II).

Methods

The participants were 104 amnestic mild cognitive impairment (aMCI), 74 vascular mild cognitive impairment (VaMCI), 73 dementia of the Alzheimer's type (DAT), and 41 vascular dementia (VaD) patients. All participants were administered the Korean-MoCA and SNSB-II.

Results

Like the MoCA total score, the MoCA-OIS, MoCA-VIS, and MoCA-MIS showed differences between aMCI and AD groups and between VaMCI and VaD groups. The MoCA-AIS, MoCA-LIS, and MoCA-EIS showed significant differences between VaMCI and VaD groups, but no difference between aMCI and DAT groups. In the aMCI and VaMCI groups, all index scores of the MoCA showed significant correlations with the corresponding cognitive domain scores of the SNSB-II. Except for MoCA-MIS, the MoCA-AIS, MoCA-LIS, MoCA-VIS, and MoCA-EIS also showed significant correlations with the corresponding domain scores of the SNSB-II in the DAT and VaD groups.

Conclusions

These results indicate that all MoCA index scores, except for MoCA-MIS, which does not reflect the severity of memory impairment in dementia patients, provide highly valid information on the function of each cognitive domain in patients with mild cognitive impairment and dementia.

Consumption of Ashtanga Ghrita (clarified cow butter added with herb extracts) improves cognitive dysfunction induced by scopolamine in rats via regulation of acetylcholinesterase activity and oxidative stress

OBJECTIVES

Ashtanga Ghrita (AG), an Indian traditional formulation, has been used to promote neuropharmacological activities. AG is made up of clarified cow butter (ghee) and eight different herbs.

METHODS

To test whether scopolamine (SCP)-induced dementia and brain oxidative stress can be counteracted by AG, rats were separated into five groups (n=6/group): group one control, group two SCP (1 mg/kg b.w., i.p.) treated and group three to five were co-treated with different doses of AG (1.25, 2.5 and 5 g/kg b.w., orally) and SCP. After the treatment regimen, behavioral (Y-maze test) and brain biochemical changes were measured in all groups.

RESULTS

Microbial load and heavy metals were found within permissible limits. Results from attenuated total reflection Fourier-transform infrared spectroscopy demonstrated the complexation/interaction of herbal phytoconstituents with the functional groups of Ghrita. Preliminary phytochemical analysis of AG exhibited the occurrence of flavonoids, phenolics, glycosides, steroids, triterpenes, tannins, and amino acids. Findings of the experimental study exhibited that AG significantly protected the rats from SCP-induced behavioral dysfunction and brain biochemical alterations.

CONCLUSIONS

This study demonstrates that AG protects the brain from SCP-induced dementia by promoting brain antioxidant activity and thus could be a promising drug for the treatment of neurodegenerative disease.

Passively-Measured Routine Home Computer Activity and Application Use Can Detect Mild Cognitive Impairment and Correlate with Important Cognitive Functions in Older Adulthood

BACKGROUND

Computer use is a cognitively complex instrumental activity of daily living (IADL) that has been linked to cognitive functioning in older adulthood, yet little work has explored its capacity to detect incident mild cognitive impairment (MCI).

OBJECTIVE

To examine whether routine home computer use (general computer use as well as use of specific applications) could effectively discriminate between older adults with and without MCI, as well as explore associations between use of common computer applications and cognitive domains known to be important for IADL performance.

METHODS

A total of 60 community-dwelling older adults (39 cognitively healthy, 21 with MCI) completed a neuropsychological evaluation at study baseline and subsequently had their routine home computer use behaviors passively recorded for three months.

RESULTS

Compared to those with MCI, cognitively healthy participants spent more time using the computer, had a greater number of computer sessions, and had an earlier mean time of first daily computer session. They also spent more time using email and word processing applications, and used email, search, and word processing applications on a greater number of days. Better performance in several cognitive domains, but in particular memory and language, was associated with greater frequency of browser, word processing, search, and game application use.

CONCLUSION

Computer and application use are useful in identifying older adults with MCI. Longitudinal studies are needed to determine whether decreases in overall computer use and specific computer application use are predictors of incident cognitive decline.

fMRI Investigation of Semantic Lexical Processing in Healthy Control and Alzheimer's Disease Subjects Using Naming Task: A Preliminary Study

For decades, scientists have been trying to solve the problem of dementia, with no cure currently available. Semantic-lexical impairment is well established as the early critical sign of dementia, although there are still gaps in knowledge that must be investigated. In this study, we used fMRI to observe the neural activity of 31 subjects, including 16 HC (Healthy Control) and 15 AD (Alzheimer's Disease), who participated in the naming task. The neuropsychology profile of HC (Healthy Control) and AD (Alzheimer's Disease) are discussed in this study. The involvement of FG (Fusiform Gyrus) and IFG (Inferior Frontal Gyrus) shows dominant activation in both of the groups. We observed a decrease in neural activity in the AD group, resulting in semantic deficit problems in this preliminary study. Furthermore, ROI analysis was performed and revealed both hyperactivation and hypoactivation in the AD group. The compensatory mechanism demonstrated during the task, due to the effort required to identify an animal's name, represents the character profile of AD.

The Association between Difficulties with Speech Fluency and Language Skills in a National Age Cohort of Children with Down Syndrome

The present study (a) addressed difficulties in speech fluency in children with Down syndrome and typically developing children at a similar non-verbal level and (b) examined the association between difficulties with speech fluency and language skills in children with Down syndrome. Data from a cross-sectional parent survey that included questions about children's difficulties with speech fluency, as well as clinical tests from a national age cohort of 43 six-year-olds with Down syndrome and 57 young typically developing children, were collected. Fisher's exact test, Student's t-test, linear regression, and density ellipse scatter plots were used for analysis. There was a significantly higher occurrence of parent-reported difficulties with speech fluency in the children with Down syndrome. Higher language scores were significantly associated with a lower degree of difficulties; this association was strongest for vocabulary and phonological skills. Although difficulties with speech fluency were not reported for all children with Down syndrome, a substantially higher occurrence of such difficulties was reported compared to that for typically developing children. The significant association between difficulties with speech fluency and the level of language functioning suggests that speech fluency and language skills should be taken into consideration when planning treatment for children with Down syndrome.

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.

Cognitive Phenotypes of Older Adults with Subjective Cognitive Decline and Amnestic Mild Cognitive Impairment: The Czech Brain Aging Study

OBJECTIVE

To compare cognitive phenotypes of participants with subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI), estimate progression to MCI/dementia by phenotype and assess classification error with machine learning.

METHOD

Dataset consisted of 163 participants with SCD and 282 participants with aMCI from the Czech Brain Aging Study. Cognitive assessment included the Uniform Data Set battery and additional tests to ascertain executive function, language, immediate and delayed memory, visuospatial skills, and processing speed. Latent profile analyses were used to develop cognitive profiles, and Cox proportional hazards models were used to estimate risk of progression. Random forest machine learning algorithms reported cognitive phenotype classification error.

RESULTS

Latent profile analysis identified three phenotypes for SCD, with one phenotype performing worse across all domains but not progressing more quickly to MCI/dementia after controlling for age, sex, and education. Three aMCI phenotypes were characterized by mild deficits, memory and language impairment (dysnomic aMCI), and severe multi-domain aMCI (i.e., deficits across all domains). A dose-response relationship between baseline level of impairment and subsequent risk of progression to dementia was evident for aMCI profiles after controlling for age, sex, and education. Machine learning more easily classified participants with aMCI in comparison to SCD (8% vs. 21% misclassified).

CONCLUSIONS

Cognitive performance follows distinct patterns, especially within aMCI. The patterns map onto risk of progression to dementia.

Incidence, gender influence, and neuropsychological predictors of all cause dementia in the Faroe Islands-the Faroese Septuagenarian cohort

BACKGROUND

Using the Faroese Septuagenarian cohort, we aimed to describe the incidence of dementia and assess the validity of neurocognitive tests to predict subsequent dementia diagnosis.

METHODS

In this population-based cohort, 713 Faroese septuagenarians aged 70-74 years without dementia, underwent clinical and neuropsychological examinations. After 10-years of follow-up, information was collected on all participants referred for cognitive evaluations and diagnosed with dementia. Incidence rates were calculated and presented with 95% confidence intervals (CIs), assuming a Poisson distribution. We then performed discriminant analysis to determine the best set of neuropsychological tests to identify those who would develop dementia.

RESULTS

Over the 10-years, 65 participants (9.1%) were diagnosed with dementia, with a 10-year incidence rate of 1063 cases per 100,000 person years (95% CI 825, 1343). Women had a greater incidence than men (incidence rate ratio (IRR) = 1.58; 95% CI 0.93, 2.71). After stepwise selection, gender and six neuropsychological measures were selected to discriminate between those who would and would not develop dementia. Overall, the model was able to correctly identify 82% of those who would not develop dementia (specificity) and 71% of those who would (sensitivity).

CONCLUSIONS

These results indicate that among a greater number of tests covering a broad range of cognitive abilities, tests reflecting verbal and visual learning and recall, visuospatial function, attention, and encoding into and retrieval from long-term memory may be helpful in identifying patients in the pre-symptomatic phase of dementia. Thus, helping care-givers identify patients at a higher risk of developing dementia and adjusting management of care accordingly.

Acceptability of collecting speech samples from the elderly via the telephone

OBJECTIVE

There is a critical need to develop rapid, inexpensive and easily accessible screening tools for mild cognitive impairment (MCI) and Alzheimer's disease (AD). We report on the efficacy of collecting speech via the telephone to subsequently develop sensitive metrics that may be used as potential biomarkers by leveraging natural language processing methods.

METHODS

Ninety-one older individuals who were cognitively unimpaired or diagnosed with MCI or AD participated from home in an audio-recorded telephone interview, which included a standard cognitive screening tool, and the collection of speech samples. In this paper we address six questions of interest: (1) Will elderly people agree to participate in a recorded telephone interview? (2) Will they complete it? (3) Will they judge it an acceptable approach? (4) Will the speech that is collected over the telephone be of a good quality? (5) Will the speech be intelligible to human raters? (6) Will transcriptions produced by automated speech recognition accurately reflect the speech produced?

RESULTS

Participants readily agreed to participate in the telephone interview, completed it in its entirety, and rated the approach as acceptable. Good quality speech was produced for further analyses to be applied, and almost all recorded words were intelligible for human transcription. Not surprisingly, human transcription outperformed off the shelf automated speech recognition software, but further investigation into automated speech recognition shows promise for its usability in future work.

CONCLUSION

Our findings demonstrate that collecting speech samples from elderly individuals via the telephone is well tolerated, practical, and inexpensive, and produces good quality data for uses such as natural language processing.

Identification of digital voice biomarkers for cognitive health

AIM

Human voice contains rich information. Few longitudinal studies have been conducted to investigate the potential of voice to monitor cognitive health. The objective of this study is to identify voice biomarkers that are predictive of future dementia.

METHODS

Participants were recruited from the Framingham Heart Study. The vocal responses to neuropsychological tests were recorded, which were then diarized to identify participant voice segments. Acoustic features were extracted with the OpenSMILE toolkit (v2.1). The association of each acoustic feature with incident dementia was assessed by Cox proportional hazards models.

RESULTS

Our study included 6, 528 voice recordings from 4, 849 participants (mean age 63 ± 15 years old, 54.6% women). The majority of participants (71.2%) had one voice recording, 23.9% had two voice recordings, and the remaining participants (4.9%) had three or more voice recordings. Although all asymptomatic at the time of examination, participants who developed dementia tended to have shorter segments than those who were dementia free (P < 0.001). Additionally, 14 acoustic features were significantly associated with dementia after adjusting for multiple testing (P < 0.05/48 = 1 × 10-3). The most significant acoustic feature was jitterDDP_sma_de (P = 7.9 × 10-7), which represents the differential frame-to-frame Jitter. A voice based linear classifier was also built that was capable of predicting incident dementia with area under curve of 0.812.

CONCLUSIONS

Multiple acoustic and linguistic features are identified that are associated with incident dementia among asymptomatic participants, which could be used to build better prediction models for passive cognitive health monitoring.

Cognitive and Behavioral Profiles of Left and Right Semantic Dementia: Differential Diagnosis with Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease

BACKGROUND

Semantic dementia (SD) is a subtype of frontotemporal dementia (FTD) characterized by semantic memory loss and preserved abilities of other cognitive functions. The clinical manifestations of SD require a differential diagnosis with Alzheimer's disease (AD), especially those with early onset, and behavioral variant FTD (bvFTD).

OBJECTIVE

The present study aimed to compare cognitive performances and neuropsychiatric symptoms in a population of AD, bvFTD, and left and right SD defined with the support of molecular imaging (amyloid and 2-[18F] fluoro-2-deoxy-D-glucose positron emission tomography) and assessed the accuracy of different neuropsychological markers in distinguishing these neurodegenerative diseases.

METHODS

Eighty-seven participants (32 AD, 20 bvFTD, and 35 SD (17 Left-SD and 18 Right-SD) completed a comprehensive neuropsychological battery that included memory, language, attention and executive functions, visuospatial function, visuoconstructional skills, and tasks designed specifically to evaluate prosopagnosia and facial emotions recognition. The Neuropsychiatric Inventory was administered to assess neuropsychiatric symptoms.

RESULTS

An episodic memory test that included semantic cues, a visuospatial test (both impaired in AD), a naming test and a prosopagnosia task (both impaired in SD) were the four most valuable cognitive metrics for the differential diagnosis between groups. Several behavioral abnormalities were differentially present, of which aggression, self-care (both more frequent in bvFTD), and eating habits, specifically overeating and altered dietary preference (more frequent in SD), were the most valuable in group discrimination.

CONCLUSION

Our study highlights the value of a comprehensive neuropsychological and neuropsychiatric evaluation for the differential diagnosis between FTD syndromes and AD.

The Role of Glutamate in Language and Language Disorders - Evidence from ERP and Pharmacologic Studies

Current models of language processing do not address mechanisms at the neurotransmitter level, nor how pharmacologic agents may improve language function(s) in seemingly disparate disorders. L-Glutamate, the primary excitatory neurotransmitter in the human brain, is extensively involved in various higher cortical functions. We postulate that the physiologic role of L-Glutamate neurotransmission extends to the regulation of language access, comprehension, and production, and that disorders in glutamatergic transmission and circuitry contribute to the pathogenesis of neurodegenerative diseases and sporadic-onset language disorders such as the aphasic stroke syndromes. We start with a review of basic science data pertaining to various glutamate receptors in the CNS and ways that they may influence the physiological processes of language access and comprehension. We then focus on the dysregulation of glutamate neurotransmission in three conditions in which language dysfunction is prominent: Alzheimer's Disease, Fragile X-associated Tremor/Ataxia Syndrome, and Aphasic Stroke Syndromes. Finally, we review the pharmacologic and electrophysiologic (event related brain potential or ERP) data pertaining to the role glutamate neurotransmission plays in language processing and disorders.

A Brief Drawing Task for the Differential Diagnosis of Semantic Dementia

BACKGROUND

Semantic dementia (SD) is a subtype of frontotemporal lobe degeneration characterized by semantic loss, with other cognitive functions initially preserved. SD requires differential diagnosis with Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD). Semantic knowledge can be evaluated through different tests; however, most of them depend on language.

OBJECTIVE

We describe the development of a brief drawing task that may be helpful for the differential diagnosis of SD.

METHODS

Seventy-two patients, including 32 AD, 19 bvFTD, and 21 SD were asked to draw 12 items with different age of acquisition and familiarity, belonging to four different semantic categories. We employed the drawings of healthy volunteers to build a scoring scheme.

RESULTS

Turtle, strawberry, train, and envelope were the items of each category that best discriminated between groups and were selected for the Brief drawing task. The discriminatory power of the Brief drawing task between SD versus AD and bvFTD patients, estimated through the area under the curve was 0.84 (95% CI = 0.72-0.96, p = 0.000007). In a logistic model, the Brief drawing task (p = 0.003) and VOSP "number location" subtest (p = 0.016) were significant predictors of the diagnosis of SD versus AD and bvFTD after adjustment by the main covariates. The Brief drawing task provided clinically useful qualitative information. SD drawings were characterized by loss of the distinctive features, intrusions, tendency to prototype, and answers like "I don't know what this is".

CONCLUSION

The Brief drawing task appears to reveal deficits in semantic knowledge among patients with SD that may assist in the differential diagnosis with other neurodegenerative diseases.

Semantic Processing in Healthy Aging and Alzheimer's Disease: A Systematic Review of the N400 Differences

Semantic deficits are common in individuals with Alzheimer’s disease (AD). These deficits notably impact the ability to understand words. In healthy aging, semantic knowledge increases but semantic processing (i.e., the ability to use this knowledge) may be impaired. This systematic review aimed to investigate semantic processing in healthy aging and AD through behavioral responses and the N400 brain event-related potential. The results of the quantitative and qualitative analyses suggested an overall decrease in accuracy and increase in response times in healthy elderly as compared to young adults, as well as in individuals with AD as compared to age-matched controls. The influence of semantic association, as measured by N400 effect amplitudes, appears smaller in healthy aging and even more so in AD patients. Thus, semantic processing differences may occur in both healthy and pathological aging. The establishment of norms of healthy aging for these outcomes that vary between normal and pathological aging could eventually help early detection of AD.

An Exploratory Study for Assessment of Multimodal Semantic Memory in Colombian Children

Semantic memory (SM) is a type of long-term memory associated with the storage of general information about the world. Here we assessed the characteristics of the SM battery, developed by Catricalà et al. (2013), in a sample of Colombian children. This battery was originally conceived to evaluate adults, and features six subtests that assess SM in different modalities, using a common set of 48 stimuli in both living and nonliving categories. The design of the current study is of a cross-sectional and exploratory type. The sample was composed of 111 children, 57 boys (51%) and 54 girls (49%), who were 6 (n = 68) and 7 (n = 43) years old and had no intellectual disability. Robust linear regression models and correlation networks were used. We found an effect of age on general intelligence after correcting for gender, and no differences on the six subtest scores after corrections for gender and age were performed. Furthermore, age was found to be positively associated with the naming of colored photographs (β = .75, p = .039), naming in response to an oral description (β = 1.81, p = .039), picture sorting at four levels (β = 7.22, p = .029), and sentence verification (β = 26.66, p = .01). In addition, there were differences between the results obtained in adults in the original study and in the children of our study. This exploratory study supports the feasibility of the Spanish translation of the Catricalà et al. (2013) battery to assess SM in children with a nonclinical condition. Future studies are needed to evaluate the psychometric properties of this SM battery, and to corroborate and expand our findings in a larger sample of control children, and in children with some degree of intellectual disability or suffering of some neurodegenerative or psychiatric conditions.

Alzheimer's disease; a review of the pathophysiological basis and therapeutic interventions

Alzheimer's disease (AD) is a neurodegenerative disorder and is identified as the most common cause for dementia. Despite huge global economic burden and the impact on the close family of the patients, there is no definitive cure and thus, improved treatment methods are of need. While memory and cognition are severely affected in AD, exact etiology is yet unknown. The β-Amyloid plaque formation and aggregation hypothesis is among the well-known hypotheses used to explain disease pathogenesis. Currently there are five Food and Drug Administration (FDA) approved drugs as treatment options. All these drugs are used for symptomatic treatment of AD. Thus, disease modifying therapies which can directly address the pathological changes in AD, are needed. Such therapies could be designed based on inhibiting key steps of pathogenesis. Currently there are novel AD drug candidates with various therapeutic mechanisms, undergoing different stages of drug development. Extensive research is being done globally to broaden understanding of the exact mechanisms involved in AD and to develop therapeutic agents that can successfully hinder the occurrence and progression of the disease. In this review, a comprehensive approach to understanding AD and suggestions to be considered in the development of therapeutics for it are presented.

Cognitive impairment in Parkinson's disease is multifactorial: A neuropsychological study

BACKGROUND

In Parkinson's disease, mild cognitive impairment and dementia are associated with α-synuclein deposition and spread. However, coexistent Alzheimer's disease and cerebrovascular disease are common at autopsy, and may affect cognition. Our objective was to map cognitive impairment in Parkinson's disease to these different causes using clinical assessment.

METHODS

Neuropsychological testing was performed in a cross-sectional sample of cognitively impaired patients with Parkinson's disease. The pattern of deficits in varying cognitive domains was mapped to the presentations that typify different diseases. Data were analysed by an expert multidisciplinary panel, referencing diagnostic criteria, to reach a consensus diagnosis for the cognitive dysfunction.

RESULTS

There were 45 participants with Parkinson's disease and cognitive impairment, 73.3% male, mean age 69.1 years (SD 8.3). Twenty-seven (60.0%) had mild cognitive impairment, and 18 had dementia (40.0%). Cognitive impairment was primarily attributable to Lewy body disease alone in 19 of 45 patients (42.2%), to Lewy body disease plus Alzheimer's in 14 of 45 (31.1%), to Lewy body plus cerebrovascular disease in 6 of 45 (13.3%), and to Lewy body plus Alzheimer's and cerebrovascular disease in 1 of 45 (2.2%). The cognitive decline was not primarily Lewy-related in 5 of 45 patients (11.1%); in 4 of 45 (8.9%), it was primarily attributable to Alzheimer's disease, and 1 of 45 (2.2%) had behavioural-variant frontotemporal dementia.

CONCLUSION

Neuropsychological testing identifies distinct patterns of cognitive impairment in Parkinson's disease that provide clear pointers to comorbid disease processes, the most common being Alzheimer's disease. This approach may prove useful in clinical practice and has implications for clinical trials that target α-synuclein.