Quanti-qualitative components of the semantic verbal fluency test in cognitively healthy controls, mild cognitive impairment, and dementia subtypes

Lewy Body Dementia Research in Latin America: A Scoping Review

BACKGROUND

Dementia research in Latin America (LA) has primarily focused on Alzheimer's Disease and Frontotemporal Dementia, while Lewy body dementia (LBD) has been largely forgotten.

OBJECTIVE

We aimed to review the available evidence on LBD in LA, offering a comprehensive perspective for understanding the lack of reports and the unique challenges and characteristics of this region.

METHODS

We carried out a scoping review in databases: PubMed, EMBASE, LILACS, and Web of Science. Original studies that included participants with LBD were analyzed.

RESULTS

Of the 1388 studies identified, 70 met the inclusion criteria for this review. Among them, 63 were cross-sectional studies, three were cohort studies, two followed a case-control methodology, and only two were non-randomized clinical trials. These studies primarily examined clinical manifestations, risk factors, neuropsychiatric and non-motor symptoms, as well as cognitive impairment and its assessment in LBD within LA. Regarding geographical distribution, 52 studies were conducted in Brazil, seven in Argentina, the rest in Peru, Mexico, Colombia, Cuba, and Chile.

CONCLUSIONS

LBD research in LA is underrepresented, with most studies being cross-sectional, few utilizing a longitudinal design, and only two clinical trials, both of which lack rigorous methodology. Challenges include weak study designs, high heterogeneity, limited trials, and unclear differentiation within the LBD spectrum. Addressing these gaps requires increasing awareness, strengthening research capacity, securing funding, and fostering international collaboration.

Relationships among cortical activation, cognition, and blood biomarkers in two types of dementia determined using functional near-infrared spectroscopy

Objective

The most prevalent types of dementia in older adults are Alzheimer's disease (AD) and Lewy body dementia (LBD), and they have overlapping clinical symptoms. We aimed to define amounts of cortical activation and to identify indicators of brain function to better distinguish between these types of dementia and aid diagnosis using functional near-infrared spectroscopy (fNIRS).

Methods

Oxygenated hemoglobin (HbO) concentrations in the brains of patients with AD and LBD were detected using fNIRS. Brain function was assessed using a verbal fluency task (VFT). Resting-state and task-state cortical activations were investigated to determine differences between AD and LBD. Blood samples were analyzed to identify relevant biomarkers. The clinical and HbO variables were compared between AD and LBD. Functional connectivity at rest and correlations between HbO variables and blood biomarkers were analyzed. The sensitivity and specificity of the parameters for differentiating the dementias were evaluated using areas under the receiver operating characteristic (ROC) curves (AUCs).

Results

This study recruited 28 inpatients with AD and 25 with LBD. Mean HbO concentrations did not significantly differ in the resting state (p > 0.05), whereas functional connectivity significantly differed (t = -3.449, p = 0.001) between the groups. Mean HbO concentrations during the VFT, were significantly lower in the left temporal (p = 0.031), right dorsolateral prefrontal (p = 0.001), and right temporal (p = 0.011) cortices of the AD, than the LBD group. Blood amyloid-β (Aβ)42 levels were significantly higher in the AD group (p = 0.023), whereas significantly more α-synuclein was expressed in the LBD group (p = 0.012). Correlation analysis of cognition-related blood biomarkers with HbO concentrations associated higher plasma Aβ42 level with lower HbO concentrations in the right pre-motor and supplementary motor cortex (r = -0.378; p = 0.005) and higher glial fibrillary acidic protein (GFAP) levels in the lower right pars triangularis (r = -0.378; p = 0.006) at rest. Levels of the blood biomarker Aβ significantly and negatively correlated with HbO concentrations in the right temporal cortex (r = -0.329, p = 0.016) during the VFT. The AUC was significantly higher for the combination of multiple fNIRS indicators compared with individual cognitive or blood indicators (AUC = 0.9314).

Conclusion

The characteristics of HbO measured using fNIRS can help distinguish AD from LBD in older adults.

Application of mini-mental state examination and Montreal Cognitive Assessment in the diagnosis of dementia with Lewy bodies and Alzheimer's disease

BACKGROUND

Dementia with Lewy Bodies (DLB) and Alzheimer's disease (AD) are two types of dementia with a relatively high incidence, and their clinical manifestations are easily confused. However, the cognitive impairment characteristics of the two diseases are different, and the results of cognitive assessment can help the diagnosis of the disease.

OBJECTIVE

To explore the different characteristics of Mini-mental State Examination (MMSE) and Montreal Cognitive Assessment Scale (MoCA) in DLB and AD patients, and to explore potential markers to distinguish AD and DLB.

METHODS

This study included 66 patients with DLB, 81 with AD, and 58 cognitively normal subjects. All of them completed MMSE, MoCA, and Clinical Dementia Rating (CDR).

RESULTS

Compared with NC, both DLB and AD participants demonstrated statistically lower scores in the total and subitem domains of MMSE and MoCA (p < 0.05). When CDR was less than 2, DLB patients had better performance than AD in two subtests including memory and orientation (p < 0.05), demonstrated worse performance in most subtest including executive function, writing, visuospatial abilities, and attention (p < 0.05). Nonetheless, no notable distinction in scores existed for the DLB and AD groups with a CDR score of 2 (p > 0.05).

CONCLUSION

We observed distinct cognitive performances in subjects from both the DLB and AD groups across different stages of dementia. Our study confirms the high value of MMSE and MoCA in distinguishing patients with DLB and AD in the early stages of the disease, and they can improve the differential diagnosis of DLB and AD.

The Impact of Lexical-semantic Impairment on Spoken Verb Production in Individuals With Mild Cognitive Impairment

BACKGROUND

Although episodic memory is the primary concern in individuals with mild cognitive impairment (MCI), other cognitive functions may also be affected, including language. Language impairment in individuals with MCI has been attributed primarily to the breakdown of semantic representations, difficulties in accessing semantic information, and the weakening of executive functions. However, in most prior studies of word processing in individuals with MCI, researchers have used measures focused on noun production.

OBJECTIVE

To investigate how verb production tasks might aid in detecting cognitive impairment in individuals with MCI.

METHODS

We compared the performance of 45 individuals with MCI and 45 healthy controls on action naming and action fluency tasks.

RESULTS

In the action naming task, the performance of participants with MCI was significantly impaired compared to healthy controls in terms of total score, the number of semantic errors produced, and the use of generic terms. In the action fluency task, participants with MCI produced significantly fewer verbs, fewer clusters, and fewer switches than healthy controls.

CONCLUSION

The results of our study emphasize the utility of verb production tasks in the identification of cognitive impairment in individuals with MCI and provide evidence of the importance of including action naming and action fluency tasks in the assessment of individuals with MCI.

Exploring Verbal Fluency Strategies among Individuals with Normal Cognition, Amnestic and Non-Amnestic Mild Cognitive Impairment, and Alzheimer's Disease

Background and Objectives: The present study explored the utilization of verbal fluency (VF) cognitive strategies, including clustering, switching, intrusions, and perseverations, within both semantic (SVF) and phonemic (PVF) conditions, across a continuum of neurocognitive decline, spanning from normal cognitive ageing (NC) to mild cognitive impairment (MCI) and its subtypes, amnestic (aMCI) and non-amnestic (naMCI), as well as AD. Materials and Methods: The study sample was derived from the Hellenic Longitudinal Investigation of Aging and Diet (HELIAD) cohort. The sample included 1607 NC individuals, 146 with aMCI (46 single-domain and 100 multi-domain), 92 with naMCI (41 single-domain and 51 multi-domain), and 79 with AD. Statistical analyses, adjusting for sex, age, and education, employed multivariate general linear models to probe differences among these groups. Results: Results showed that AD patients exhibited poorer performance in switching in both VF tasks and SVF clustering compared to NC. Similarly, the aMCI group performed worse than the NC in switching and clustering in both tasks, with aMCI performing similarly to AD, except for SVF switching. In contrast, the naMCI subgroup performed similarly to those with NC across most strategies, surpassing AD patients. Notably, the aMCI subgroup's poor performance in SVF switching was mainly due to the subpar performance of the multi-domain aMCI subgroup. This subgroup was outperformed in switching in both VF tasks by the single-domain naMCI, who also performed better than the multi-domain naMCI in SVF switching. No significant differences emerged in terms of perseverations and intrusions. Conclusions: Overall, these findings suggest a continuum of declining switching ability in the SVF task, with NC surpassing both aMCI and AD, and aMCI outperforming those with AD. The challenges in SVF switching suggest executive function impairment associated with multi-domain MCI, particularly driven by the multi-domain aMCI.

How well does the discrepancy between semantic and letter verbal fluency performance distinguish Alzheimer's dementia from typical aging?

In Alzheimer's dementia (AD), greater declines in semantic fluency (SF) relative to letter fluency (LF) have been assumed to reflect semantic disintegration. However, the same pattern is observed in typical aging and neurodegenerative disorders besides AD. We examined this assumption by comparing different aspects of SF and LF performance in older adults with and without dementia, and identifying which verbal fluency measures most clearly distinguish AD from typical aging. Verbal fluency data were compared from 109 individuals with AD and 66 typically aging adults. Correct items, clusters, and errors were analyzed using both raw counts and proportions. Regression analyses examined Task-by-Group interactions and the impact of demographic variables on verbal fluency measures. ROC analyses examined the sensitivity and specificity of the different outcome measures. In regressions, interactions were found for raw but not proportional data, indicating that different group patterns were driven largely by the number of correct items produced. Similarly, in ROC analyses, raw SF totals showed stronger discriminability between groups than either raw discrepancy scores (SF-LF) or discrepancy ratios (SF/LF). Age and cognitive status (MMSE) were the strongest individual predictors of performance. Findings suggest that AD entails quantitative declines in verbal fluency, but qualitatively similar patterns of performance relative to typically aging adults. Thus, SF declines in AD seem to be at least partially attributable to an exaggeration of the underlying mechanisms common to typical aging, and do not necessarily implicate semantic disintegration.

The Accuracy of Speech and Linguistic Analysis in Early Diagnostics of Neurocognitive Disorders in a Memory Clinic Setting

OBJECTIVE

To investigate whether automatic analysis of the Semantic Verbal Fluency test (SVF) is reliable and can extract additional information that is of value for identifying neurocognitive disorders. In addition, the associations between the automatically derived speech and linguistic features and other cognitive domains were explored.

METHOD

We included 135 participants from the memory clinic of the Maastricht University Medical Center+ (with Subjective Cognitive Decline [SCD; N = 69] and Mild Cognitive Impairment [MCI]/dementia [N = 66]). The SVF task (one minute, category animals) was recorded and processed via a mobile application, and speech and linguistic features were automatically extracted. The diagnostic performance of the automatically derived features was investigated by training machine learning classifiers to differentiate SCD and MCI/dementia participants.

RESULTS

The intraclass correlation for interrater reliability between the clinical total score (golden standard) and automatically derived total word count was 0.84. The full model including the total word count and the automatically derived speech and linguistic features had an Area Under the Curve (AUC) of 0.85 for differentiating between people with SCD and MCI/dementia. The model with total word count only and the model with total word count corrected for age showed an AUC of 0.75 and 0.81, respectively. Semantic switching correlated moderately with memory as well as executive functioning.

CONCLUSION

The one-minute SVF task with automatically derived speech and linguistic features was as reliable as the manual scoring and differentiated well between SCD and MCI/dementia. This can be considered as a valuable addition in the screening of neurocognitive disorders and in clinical practice.

Efficacy and Moderators of Virtual Reality for Cognitive Training in People with Dementia and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Mild cognitive impairment (MCI) and dementia result in cognitive decline which can negatively impact everyday functional abilities and quality of life. Virtual reality (VR) interventions could benefit the cognitive abilities of people with MCI and dementia, but evidence is inconclusive.

OBJECTIVE

To investigate the efficacy of VR training on global and domain-specific cognition, activities of daily living and quality of life. To explore the influence of priori moderators (e.g., immersion type, training type) on the effects of VR training. Adverse effects of VR training were also considered.

METHODS

A systematic literature search was conducted on all major databases for randomized control trial studies. Two separate meta-analyses were performed on studies with people with MCI and dementia.

RESULTS

Sixteen studies with people with MCI and four studies with people with dementia were included in each meta-analysis. Results showed moderate to large effects of VR training on global cognition, attention, memory, and construction and motor performance in people with MCI. Immersion and training type were found to be significant moderators of the effect of VR training on global cognition. For people with dementia, results showed moderate to large improvements after VR training on global cognition, memory, and executive function, but a subgroup analysis was not possible.

CONCLUSION

Our findings suggest that VR training is an effective treatment for both people with MCI and dementia. These results contribute to the establishment of practical guidelines for VR interventions for patients with cognitive decline.

A simple counting of verbal fluency errors discriminates between normal cognition, mild cognitive impairment and Alzheimer's disease

For this observational cross-sectional study, different modalities of verbal fluency tasks (VFTs) were compared between 143 participants: 35 cognitively healthy controls (CHCs), 71 mild cognitive impairment (MCI) and 37 mild Alzheimer's disease (AD) patients. Binomial logistic regression models were defined to identify VFT variables associated with MCI and AD, with respect to CHC. The results showed that the best errors/repetitions variable associated with MCI and AD was the phonemic task, and with every error the odds of being in the MCI group increased 9.9 times and 12.2 times in AD group, accompanied by high accuracy values (MCI: AUC = 0.824, sensitivity = 0.676, specificity = 0.943; AD: AUC = 0.883, sensitivity = 0.784, specificity = 0.943). The results suggest that, in addition to solely register raw scores, a simple counting of errors and repetitions during VFT can offer valuable clues in detecting MCI and AD, especially in the phonemic task.

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.

Verbal fluency in Alzheimer's disease and mild cognitive impairment in individuals with low educational level and its relationship with reading and writing habits

Verbal fluency (VF) has contributed to building cognitive maps as well as differentiating healthy populations from those with dementia.

Objectives

To compare the performance of healthy controls and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD) in two semantic VF tasks (animals/clothes) and a phonemic VF task (letter P). Also, to analyze the relationship between the frequency of reading and writing habits (FRWH) and VF in individuals with low educational level.

Methods

Sixty-seven older adults aged 60-80 years and with 2-8 years of schooling were divided into three groups: controls (n=25), older adults with MCI (n=24), and older adults with AD (n=18). We analyzed the type, mean size, and number of clusters, switches, intersections, and returns. A post-hoc single-factor ANOVA analysis was conducted to verify differences between groups.

Results

Total words in the phonemic VF and the animal category discriminated the three groups. Regarding the animal category, AD patients performed worse than controls in the total number of words, taxonomic clusters, returns, and number of words remembered. We found a moderate correlation between FRWH and total number of words in the phonemic fluency.

Conclusions

Semantic (animate) and phonemic (total words) VF differentiated controls and clinical groups from each other - the phonemic component was more related to FRWH than the semantic one. The phonemic VF seems to be more related to cognitive reserve. VF tasks, considering total words and cluster analyses, are a valuable tool to test healthy and cognitively impaired older adults who have a low educational level.

Marrying Past and Present Neuropsychology: Is the Future of the Process-Based Approach Technology-Based?

A cognitive assessment strategy that is not limited to examining a set of summary test scores may be more helpful for early detection of emergent illness such as Alzheimer's disease (AD) and may permit a better understanding of cognitive functions and dysfunctions in those with AD and other dementia disorders. A revisit of the work already undertaken by Kaplan and colleagues using the Boston Process-Approach provides a solid basis for identifying new opportunities to capture data on neurocognitive processes, test-taking strategies and response styles. Thus, this critical review will combine traditional process-based assessment strategies with support provided or offered by newer technologies that have the potential to add value to data collection and interpretation. There is now considerable interest in neuropsychological test administration using computer/digital technology, both in research and in clinical settings. To add value, any computerized version of an existing cognitive test should respect the administration procedure for which normative data were obtained, should be time-saving in terms of scoring and interpretation, and should, we argue, facilitate gathering information about the processes and strategies followed in test completion. This article will offer an overview of the steps needed when implementing computerization of neuropsychological tests using a Process-Based Approach (PBA) to these technology-based adaptations and will discuss further developments in this area by linking it to future technological developments that may be possible in the area of neuropsychological assessment. Additionally, an overview of neuropsychological tests that may benefit from computerization will be presented, together with suggestions on the specific processes, strategies and features that may be captured with the aid of such computerization. Finally, hypotheses on how virtual reality could be an asset for the future of the PBA to neuropsychological assessment will also be discussed.