Drawing Disorders in Alzheimer's Disease and Other Forms of Dementia

Visuospatial memory in apraxia: Exploring quantitative drawing metrics to assess the representation of local and global information

Neuropsychological evidence suggests that visuospatial memory is subserved by two separable processing systems, with dorsal underpinnings for global form and ventral underpinnings for the integration of part elements. Previous drawing studies have explored the effects of Gestalt organisation upon memory for hierarchical stimuli, and we here present an exploratory study of an apraxic dorsal stream patient's (MH) performance. We presented MH with a stimulus set (previously reported by Riddoch et al., Cognitive Neuropsychology, 20(7), 641-671, 2003) and devised a novel quantitative scoring system to obtain a finer grain of insight into performance. Stimuli possessed either good or poor Gestalt qualities and were reproduced in a copy condition and two visual memory conditions (with unlimited viewing before the model was removed, or with 3 s viewing). MH's copying performance was impaired in comparison to younger adult and age-matched older adult controls, with a variety of errors at the local level but relatively few at the global level. However, his performance in the visual memory conditions revealed impairments at the global level. For all participants, drawing errors were modulated by the Gestalt qualities of the stimuli, with accuracy at the global and local levels being lesser for poor global stimuli in all conditions. These data extend previous observations of this patient, and support theories that posit interaction between dorsal and ventral streams in the representation of hierarchical stimuli. We discuss the implications of these findings for our understanding of visuospatial memory in neurological patients, and also evaluate the application of quantitative metrics to the interpretation of drawings.

Effectiveness of Early Multimodal Non-pharmacological Interventions in Cognitive Preservation in the Elderly

INTRODUCTION

Multimodal non-pharmacological interventions (MNPI) have been determined as effective in delaying cognitive deterioration. The effectiveness of timing of such interventions in elderly is less discussed. We compared the different effectiveness of MNPI in cognitive preservation in elderly subjects with and without dementia.

METHODS

We enrolled volunteer the elderly subjects. Subjects were classified as dementia group and non-dementia group by instrument of ascertainment of dementia 8. All were assigned to attend 3 hours of MNPI (physical fitness training, Chinese capillary, and Chinese drawings and paintings) twice a week over a 16-week period. Neuropsychiatric tests, including Mini-Mental State Examination (MMSE), Cognitive Assessment Screening Instrument (CASI), clinical dementia rating (CDR), and neuropsychiatric inventory (NPI), were administered before and 1 year after MNPI. We demonstrated the changes of cognition and behavioral and psychological symptoms of dementia (BPSD) before and after MNPI. We compared the different effectiveness of cognition preservation between two groups.

RESULTS

In total, there were 43 participants in our study, including 18 with non-dementia and 25 with dementia. The non-dementia group had a significantly higher proportion of cognitive preservation in remote memory (100.0% vs 68.0%, P = .007), orientation (94.4% vs 48.0%, P = .001), drawing (94.4% vs 64.0%, P = .021) and language (77.8% vs 48.0%, P = .049) than the dementia group. The highest proportion of preserved cognition after MNPI was remote memory (100%), followed by orientation (94.4%) and drawing (94.4%) in the non-dementia group. The highest proportion of preserved cognition after MNPI was attention (72%) followed by remote memory (68%), recent memory (64%) and drawing (64%) in the dementia group. Overall, their improved rate in behavioral and psychological symptoms was 55.6%.

CONCLUSION

Our study concluded the benefits of early MNPI in cognition preservation in the elderly, especially in the field of remote memory, orientation, drawing and language.

[Clinical examination of spatial neglect and other disorders of spatial cognition]

Neglect occurring after stroke, neoplasms or degenerative processes can lead to considerable disability in everyday life as can other disorders of spatial orientation. Therefore, a dedicated examination and early diagnostic classification are obligatory. Behavioral tests are helpful in this respect, enabling the clinician to obtain an initial overview of the existing deficits even at the patient's bedside. The clinical (bedside) examination of spatial neglect as well as the corresponding differential diagnostic procedure for the clarification of (possibly additionally or exclusively existing) hemianopia and extinction, as well as the examination of disorders of visuospatial perception, visuoconstructive disorders, topographic disorders, Bálint's syndrome, simultanagnosia, and optic ataxia are presented. The presentation is based on the newly revised (year 2023) guidelines of the Association of the Scientific Medical Societies in Germany (AWMF) on this subject area.

Magnetic resonance evidence of increased iron content in subcortical brain regions in asymptomatic Alzheimer's disease

While iron over-accumulation has been reported in late stage Alzheimer's disease (AD), whether this occurs early in the asymptomatic stage of AD remains unknown. We aimed to assess brain iron levels in asymptomatic AD using quantitative MR relaxometry of effective transverse relaxation rate (R2*) and longitudinal relaxation rate (R1), and recruited 118 participants comprised of three groups including healthy young participants, and cognitively normal older individuals without or with positive AD biomarkers based on cerebrospinal fluid (CSF) proteomics analysis. Compared with the healthy young group, increased R2* was found in widespread cortical and subcortical regions in the older groups. Further, significantly higher levels of R2* were found in the cognitively normal older subjects with positive CSF AD biomarker (i.e., asymptomatic AD) compared with those with negative AD biomarker in subcortical regions including the left and right caudate, left and right putamen, and left and right globus pallidus (p < .05 for all regions), suggesting increased iron content in these regions. Subcortical R2* of some regions was found to significantly correlate with CSF AD biomarkers and neuropsychological assessments of visuospatial functions. In conclusion, R2* could be a valuable biomarker for studying early pathophysiological changes in AD.

Neural basis of visuospatial tests in behavioral variant frontotemporal dementia

Background

Recent models of visuospatial functioning suggest the existence of three main circuits emerging from the dorsal (“where”) route: parieto-prefrontal pathway, parieto-premotor, and parieto-medial temporal. Neural underpinnings of visuospatial task performance and the sparing of visuospatial functioning in bvFTD are unclear. We hypothesized different neural and cognitive mechanisms in visuospatial tasks performance in bvFTD and AD.

Methods

Two hundred and sixteen participants were enrolled for this study: 72 patients with bvFTD dementia and 144 patients with AD. Visual Object and Space Perception Battery Position Discrimination and Number Location (VOSP-PD and VOSP-NL) and Rey-Osterrieth Complex Figure (ROCF) were administered to examine visuospatial functioning, together with a comprehensive neuropsychological battery. FDG-PET was acquired to evaluate brain metabolism. Voxel-based brain mapping analyses were conducted to evaluate the brain regions associated with visuospatial function in bvFTD and AD.

Results

Patients with AD performed worst in visuospatial tasks in mild dementia, but not at prodromal stage. Attention and executive functioning tests showed higher correlations in bvFTD than AD with ROCF, but not VOSP subtests. Visuospatial performance in patients with bvFTD was associated with bilateral frontal regions, including the superior and medial frontal gyri, supplementary motor area, insula and middle cingulate gyrus.

Conclusion

These findings support the role of prefrontal and premotor regions in visuospatial processing through the connection with the posterior parietal cortex and other posterior cortical regions. Visuospatial deficits should be interpreted with caution in patients with bvFTD, and should not be regarded as hallmarks of posterior cortical dysfunction.

The relationship between cognitive reserve and cognition in healthy adults: a systematic review

The concept of Cognitive Reserve (CR) refers to the individual differences allowing some people to cope better with brain pathology. The aim of the present review was to explore the relationship between CR and cognition in adulthood. This association has been addressed in several neuro(psycho)logical disorders and in healthy elderly people. However, few studies explored this issue in adulthood (age range 18–65), when individuals might take advantage the most from psychoeducational approaches aimed at increasing CR. For our systematic review, we selected studies assessing CR and adopting neuropsychological and experimental tasks for evaluation of cognitive functioning in healthy individuals. In the selected articles, we examined the relationship of singular proxies, composite indexes or standardized scales of CR with measures of general cognition, attention, inhibitory control, verbal fluency, constructional abilities, and verbal and spatial memory. The results suggested a positive relationship between singular CR proxies, composite indexes or standardized scales, and almost all the explored cognitive domains. No clear conclusion could be made on constructional abilities due to the scarcity of available studies. CR seems associated with better cognitive performance in adulthood, but definite methodological improvements and the use of standardized scales for CR are necessary to reduce inconsistencies among studies.

Functional Specificity of TPS Brain Stimulation Effects in Patients with Alzheimer's Disease: A Follow-up fMRI Analysis

Introduction

Transcranial pulse stimulation (TPS) has been recently introduced as a novel clinical brain stimulation technique based on highly focused ultrasound pressure pulses. In a first pilot study on clinical effects of navigated and focused ultrasound neuromodulation, a dichotomy of functional effects was found: patients with Alzheimer’s disease improved cognition and language but deteriorated with visuo-constructive functions.

Methods

We analyzed changes in functional connectivity measured with functional magnetic resonance imaging (fMRI) using graph analysis of a visuo-constructive network in 18 patients with Alzheimer’s disease. We calculated the network’s global efficiency and tested for correlation with visuo-constructive test scores to explain this dichotomy.

Results

Important visuo-constructive network nodes were not stimulated in the pilot setting and correspondingly global efficiency of a visuo-constructive network was decreased after TPS therapy, compatible with a natural progress of the disease. A correlation between visuo-constructive scores and changes in global efficiency was found.

Conclusion

Results argue for a high functional specificity of ultrasound-based neuromodulation with TPS.

Over the last decade, there has been growing interest in ultrasound-based non-invasive brain stimulation techniques in neuroscience and as a potential therapy for disorders of the brain. Transcranial pulse stimulation (TPS) has been introduced as an innovative neuromodulation technique, applying ultrashort pressure pulses through the skull into neural tissue with 3D navigation in real time. In the first clinical pilot study, patients suffering from Alzheimer’s disease showed an increase in memory and language functions for up to 3 months after TPS therapy. However, visuo-constructive capacities (e.g., copying a geometrical figure) worsened. Notably, brain areas relevant for such processes had been left out during stimulation. This begged the question whether the brain areas that were targeted for brain stimulation as well as functional changes could explain this diverse response pattern. We therefore analyzed functional magnetic resonance data from patients. Specifically, we compared graph theoretical functional connectivity measures in a visuo-constructive network before and after TPS therapy. We found a decrease in connectivity in a central network node, which also correlated with visuo-constructive test scores. This deterioration is likely associated with normal disease progression. Together with the already reported improvement in global cognitive functions, these results argue for a functional specific effect of TPS.

Comparing drawing under instructions with image copying for mild cognitive impairment (MCI) or dementia screening: a meta-analysis of 92 diagnostic studies

OBJECTIVES

Drawing is a major component of cognitive screening for dementia. It can be performed without language restriction. Drawing pictures under instructions and copying images are different screening approaches. The objective of this study was to compare the diagnostic performance between drawing under instructions and image copying for MCI and dementia screening.

METHOD

A literature search was carried out in the OVID databases with keywords related to drawing for cognitive screening. Study quality and risk of bias were assessed by QUADAS-2. The level of diagnostic accuracy across different drawing tests was pooled by bivariate analysis in a random effects model. The area under the hierarchical summary receiver-operating characteristic curve (AUC) was constructed to summarize the diagnostic performance.

RESULTS

Ninety-two studies with sample size of 22,085 were included. The pooled results for drawing under instructions showed a sensitivity of 79% (95% CI: 76 - 83%) and a specificity of 80% (95% CI: 77 - 83%) with AUC of 0.87 (95% CI: 0.83 - 0.89). The pooled results for image copying showed a sensitivity of 71% (95% CI: 62 - 79%) and a specificity of 83% (95% CI: 72 - 90%) with AUC of 0.83 (95% CI: 0.80 - 0.86). Clock-drawing test was the screening test used in the majority of studies.

CONCLUSION

Drawing under instructions showed a similar diagnostic performance when compared with image copying for cognitive screening and the administration of image copying is relatively simpler. Self-screening for dementia is feasible to be done at home in the near future.

The Visuospatial and Sensorimotor Functions of Posterior Parietal Cortex in Drawing Tasks: A Review

Drawing is a comprehensive skill that primarily involves visuospatial processing, eye-hand coordination, and other higher-order cognitive functions. Various drawing tasks are widely used to assess brain function. The neuropsychological basis of drawing is extremely sophisticated. Previous work has addressed the critical role of the posterior parietal cortex (PPC) in drawing, but the specific functions of the PPC in drawing remain unclear. Functional magnetic resonance imaging and electrophysiological studies found that drawing activates the PPC. Lesion-symptom mapping studies have shown an association between PPC injury and drawing deficits in patients with global and focal cerebral pathology. These findings depicted a core framework of the fronto-parietal network in drawing tasks. Here, we review neuroimaging and electrophysiological studies applying drawing paradigms and discuss the specific functions of the PPC in visuospatial and sensorimotor aspects. Ultimately, we proposed a hypothetical model based on the dorsal stream. It demonstrates the organization of a PPC-centered network for drawing and provides systematic insights into drawing for future neuropsychological research.

Distinct brain dysfunctions underlying visuo-constructive deficit in DLB and AD

Visuo-constructive abilities are a multicomponential process that can be impaired in several neurodegenerative dementias. Among visuo-constructive tasks, the Rey-Osterrieth Complex Figure-copy (ROCF-c) is the most commonly used and it seems influenced by different skills mediated by specific brain regions. This task complexity allows exploring differential mechanisms of impairment in different neurodegenerative disorders. In this study we examined the neuroanatomical substrates of ROCF-c performance in patients with Dementia with Lewy Bodies (DLB) and patients with Alzheimer's disease (AD). We included forty-five patients with probable DLB, and thirty-four patients with probable typical-AD. To identify the ROCF-c scores neural correlates we performed a regression analysis with brain hypometabolism using the ROCF-c scores as independent variable. Then we evaluated the correlation between regional hypometabolism and ROCF-c scores in each group separately, throughout offline Pearson correlation analysis. The DLB and AD groups differed only in visuo-constructive and memory performances. DLB patients performed worse at the visuo-constructive test, while typical-AD patients performed worse at the verbal memory task. In DLB, worse performance at ROCF-c scores (more severe visuo-constructive impairment) correlated with occipital and temporo-parietal hypometabolism. In AD, worse performance at ROCF-c score was associated with brain hypometabolism in the temporo-parietal regions. The inability to correctly perform the ROCF-c derives from distinct brain dysfunctions in DLB and AD. The present results suggest alterations in visuoperceptual processes due to the severe occipital hypometabolism in DLB, and in visuospatial processes related to temporo-parietal hypometabolism in AD.

Assessing visuo-constructive functions in patients with subjective cognitive decline, mild cognitive impairment and Alzheimer’s disease with the Vienna Visuo-Constructional Test 3.0 (VVT 3.0)

Background

Visuo-Constructive functions have considerable potential for the early diagnosis and monitoring of disease progression in Alzheimer’s disease.

Objectives

Using the Vienna Visuo-Constructional Test 3.0 (VVT 3.0), we measured visuo-constructive functions in subjective cognitive decline (SCD), mild cognitive impairment (MCI), Alzheimer’s disease (AD), and healthy controls to determine whether VVT performance can be used to distinguish these groups.

Materials and methods

Data of 671 participants was analyzed comparing scores across diagnostic groups and exploring associations with relevant clinical variables. Predictive validity was assessed using Receiver Operator Characteristic curves and multinomial logistic regression analysis.

Results

We found significant differences between AD and the other groups. Identification of cases suffering from visuo-constructive impairment was possible using VVT scores, but these did not permit classification into diagnostic subgroups.

Conclusions

In summary, VVT scores are useful indicators for visuo-constructive impairment but face challenges when attempting to discriminate between several diagnostic groups.

Automated scoring for a Tablet-based Rey Figure copy task differentiates constructional, organisational, and motor abilities

Accuracy in copying a figure is one of the most sensitive measures of visuo-constructional ability. However, drawing tasks also involve other cognitive and motor abilities, which may influence the final graphic produced. Nevertheless, these aspects are not taken into account in conventional scoring methodologies. In this study, we have implemented a novel Tablet-based assessment, acquiring data and information for the entire execution of the Rey Complex Figure copy task (T-RCF). This system extracts 12 indices capturing various dimensions of drawing abilities. We have also analysed the structure of relationships between these indices and provided insights into the constructs that they capture. 102 healthy adults completed the T-RCF. A subgroup of 35 participants also completed a paper-and-pencil drawing battery from which constructional, procedural, and motor measures were obtained. Principal component analysis of the T-RCF indices was performed, identifying spatial, procedural and kinematic components as distinct dimensions of drawing execution. Accordingly, a composite score for each dimension was determined. Correlational analyses provided indications of their validity by showing that spatial, procedural, and kinematic scores were associated with constructional, organisational and motor measures of drawing, respectively. Importantly, final copy accuracy was found to be associated with all of these aspects of drawing. In conclusion, copying complex figures entails an interplay of multiple functions. T-RCF provides a unique opportunity to analyse the entire drawing process and to extract scores for three critical dimensions of drawing execution.

Nonverbal Semantics Test (NVST)-A Novel Diagnostic Tool to Assess Semantic Processing Deficits: Application to Persons with Aphasia after Cerebrovascular Accident

Assessment of semantic processing capacities often relies on verbal tasks which are, however, sensitive to impairments at several language processing levels. Especially for persons with aphasia there is a strong need for a tool that measures semantic processing skills independent of verbal abilities. Furthermore, in order to assess a patient’s potential for using alternative means of communication in cases of severe aphasia, semantic processing should be assessed in different nonverbal conditions. The Nonverbal Semantics Test (NVST) is a tool that captures semantic processing capacities through three tasks—Semantic Sorting, Drawing, and Pantomime. The main aim of the current study was to investigate the relationship between the NVST and measures of standard neurolinguistic assessment. Fifty-one persons with aphasia caused by left hemisphere brain damage were administered the NVST as well as the Aachen Aphasia Test (AAT). A principal component analysis (PCA) was conducted across all AAT and NVST subtests. The analysis resulted in a two-factor model that captured 69% of the variance of the original data, with all linguistic tasks loading high on one factor and the NVST subtests loading high on the other. These findings suggest that nonverbal tasks assessing semantic processing capacities should be administered alongside standard neurolinguistic aphasia tests.

Integrative Base Ontology for the Research Analysis of Alzheimer's Disease-Related Mild Cognitive Impairment

Early detection of mild cognitive impairment (MCI) has become a priority in Alzheimer's disease (AD) research, as it is a transitional phase between normal aging and dementia. However, information on MCI and AD is scattered across different formats and standards generated by different technologies, making it difficult to work with them manually. Ontologies have emerged as a solution to this problem due to their capacity for homogenization and consensus in the representation and reuse of data. In this context, an ontology that integrates the four main domains of neurodegenerative diseases, diagnostic tests, cognitive functions, and brain areas will be of great use in research. Here, we introduce the first approach to this ontology, the Neurocognitive Integrated Ontology (NIO), which integrates the knowledge regarding neuropsychological tests (NT), AD, cognitive functions, and brain areas. This ontology enables interoperability and facilitates access to data by integrating dispersed knowledge across different disciplines, rendering it useful for other research groups. To ensure the stability and reusability of NIO, the ontology was developed following the ontology-building life cycle, integrating and expanding terms from four different reference ontologies. The usefulness of this ontology was validated through use-case scenarios.

Does the Right Focal Variant of Alzheimer's Disease Really Exist? A Literature Analysis

BACKGROUND

Alzheimer's disease (AD) is a clinically heterogeneous disease. Multiple atypical syndromes, distinct from the usual amnesic phenotype, have been described. In this context, the existence of a right variant of AD (RAD), characterized by enduring visuospatial impairment associated with right-sided asymmetric brain damage, has been proposed. However, to date, this phenotype remains controversial. In particular, its peculiar characteristics and the independence from more prevalent cases (especially the posterior cortical atrophy syndrome) have to be demonstrated.

OBJECTIVE

To explore the existence of focal RAD on the basis of existing literature.

METHODS

We performed a literature search for the description of atypical AD presentations, potentially evoking cases of focal RAD. To be considered as affected by RAD, the described cases had to present: 1) well documented right-sided asymmetry at neuroimaging; 2) predominant cognitive deficits localizable on the right hemisphere; 3) no specific diagnosis of a known variant of AD.

RESULTS

Twenty-one cases were found in the literature, but some of them were subsequently excluded because some features of a different clinical syndrome were overlapped with the clinical features of RAD. Thirteen positive cases, three of them with pathologically confirmed AD, remained. A common right clinical-radiological syndrome, characterized by memory and visuospatial impairment with temporal and parietal involvement, consistently emerged. However, the heterogeneity among the reports prevented a definitive and univocal description of the syndrome.

CONCLUSION

Even if sporadic observations strongly support the existence of a focal RAD, no definitive conclusions can still be drawn about it as an independent condition.

The Digital Tree Drawing Test for Screening of Early Dementia: An Explorative Study Comparing Healthy Controls, Patients with Mild Cognitive Impairment, and Patients with Early Dementia of the Alzheimer Type

The digital tree drawing test (dTDT) is a newly developed screening tool for the early detection of Alzheimer's disease. It is performed with a digitizing pen, recording each pen stroke with temporal and spatial precision. It was hypothesized that movement characteristics recorded during the painting process contribute to the identification of patients with mild cognitive impairment (MCI) and early dementia of the Alzheimer type (eDAT). The study population consisted of 187 participants (67 healthy controls, 64 MCI, and 56 eDAT patients) with a mean age of 68.6±10.6 years. Between-group comparisons of the dTDT-variables were conducted with analysis of variance. The diagnostic power of dTDT variables was analyzed with stepwise logistic regressions and areas under curve (AUC) of receiver operating control curves. Cognitively impaired persons used less colors and line widths and changed them less often than healthy subjects (p-values ≤0.05). Compared to control, eDAT patients had larger not-painting periods, were slower, and their pictures had less contrast, image size, and complexity (p-values ≤0.01). Logistic regression models of stepwise selected dTDT variables resulted in an AUC of 0.84 (95% confidence interval (CI) [0.79, 0.90], sensitivity = 0.78, specificity = 0.77) for discriminating healthy subjects from all cognitive impaired, an AUC of 0.77. (95% CI [0.69; 0.85], sensitivity = 0.56, specificity = 0.83) for discriminating healthy controls from MCI patients and an AUC of 0.90 (95% CI [0.84, 0.96], sensitivity = 0.86, specificity = 0.82) for discriminating controls from eDAT patients. The results suggest that digital recording of pen-stroke data during the drawing process can contribute to the screening of cognitive impaired patients.

Constructional apraxia from the roots up: Kleist, Strauss, and their contemporaries

The concept and the term of constructional apraxia have been proposed by Karl Kleist and described in his impressive book "Gehirnpathologie", published in 1934. However, the first ever paper under the heading of constructional apraxia was written by Hans Strauss, one of Kleist's pupils, and published in 1924. Nowadays, the term constructional apraxia is still in use to refer to all disorders observed in drawing and assembling activities; its assessment, performed as it was in early studies, is part of common practice in behavioral neurology and neuropsychology. Nonetheless, the concept and the neural underpinnings of constructional apraxia have been deeply revisited with respect to the original proposal. Modern studies demonstrated that drawing and assembling are based on very large and complex brain networks extending in both hemispheres, including the left angular gyrus (as hypothesized by Kleist) but well beyond the original ideas about localization of constructional apraxia. From a clinical point of view, constructional apraxia has poor localizing value but provides valuable diagnostic information for conditions of cognitive impairment.

Psychological and Cognitive Markers of Behavioral Variant Frontotemporal Dementia-A Clinical Neuropsychologist's View on Diagnostic Criteria and Beyond

Behavioral variant frontotemporal dementia (bvFTD) is the second leading cognitive disorder caused by neurodegeneration in patients under 65 years of age. Characterized by frontal, insular, and/or temporal brain atrophy, patients present with heterogeneous constellations of behavioral and psychological symptoms among which progressive changes in social conduct, lack of empathy, apathy, disinhibited behaviors, and cognitive impairments are frequently observed. Since the histopathology of the disease is heterogeneous and identified genetic mutations only account for ~30% of cases, there are no reliable biomarkers for the diagnosis of bvFTD available in clinical routine as yet. Early detection of bvFTD thus relies on correct application of clinical diagnostic criteria. Their evaluation however, requires expertise and in-depth assessments of cognitive functions, history taking, clinical observations as well as caregiver reports on behavioral and psychological symptoms and their respective changes. With this review, we aim for a critical appraisal of common methods to access the behavioral and psychological symptoms as well as the cognitive alterations presented in the diagnostic criteria for bvFTD. We highlight both, practical difficulties as well as current controversies regarding an overlap of symptoms and particularly cognitive impairments with other neurodegenerative and primary psychiatric diseases. We then review more recent developments and evidence on cognitive, behavioral and psychological symptoms of bvFTD beyond the diagnostic criteria which may prospectively enhance the early detection and differential diagnosis in clinical routine. In particular, evidence on specific impairments in social and emotional processing, praxis abilities as well as interoceptive processing in bvFTD is summarized and potential links with behavior and classic cognitive domains are discussed. We finally outline both, future opportunities and major challenges with regard to the role of clinical neuropsychology in detecting bvFTD and related neurocognitive disorders.

Accuracy of praxis test from Cambridge Cognitive Examination (CAMCOG) for Alzheimer's disease: a cross-sectional study

BACKGROUND

Praxis impairment may be one of the first symptoms manifested in dementia, primarily in cortical dementia. The Cambridge Cognitive Examination (CAMCOG) evaluates praxis, but little is known about the accuracy of CAMCOG for diagnosing dementia. The aims here were to investigate the accuracy of praxis and its subitems in CAMCOG (constructive, ideomotor and ideational subitems) for diagnosing Alzheimer's disease (AD) among elderly patients.

DESIGN AND SETTING

Cross-sectional study on community-dwelling elderly people.

METHODS

158 elderly patients were evaluated. CAMCOG, Mini-Mental State Examination and Pfeffer Functional Activities Questionnaire were used. ROC curve analysis was used to establish cutoff points.

RESULTS

The total scores for praxis and the constructive subitem presented significant differences (P < 0.0001) between healthy elderly people and AD patients. Stage of dementia (clinical dementia rating, CDR = 0, 1 and 2) showed that total and constructive praxis can be used to classify the stages of dementia (mild and moderate cases), i.e. constructive praxis classified 88% of the patients with mild dementia (P < 0.0001) while total praxis classified 56% with moderate dementia. Comparison of normal controls (NC) and mild dementia cases showed specificity of 71% and sensitivity of 88% (AUC = 0.88; P < 0.0001).

CONCLUSION

Some praxis subtests can have higher predictive diagnostic value for detecting Alzheimer's disease in mild stages (total praxis AUC = 0.858; P < 0.0001; constructive AUC = 0.972; P < 0.0001). Constructive praxis as measured using CAMCOG may contribute towards diagnosing dementia, because occurrence of impairment of praxis may help in recognizing an evolving dementia syndrome.

Parietal Involvement in Constructional Apraxia as Measured Using the Pentagon Copying Task

Deficits in copying ("constructional apraxia") is generally defined as a multifaceted deficit. The exact neural correlates of the different types of copying errors are unknown. To assess whether the different categories of errors on the pentagon drawing relate to different neural correlates, we examined the pentagon drawings of the MMSE in persons with subjective cognitive complaints, mild cognitive impairment, or early dementia due to Alzheimer's disease. We adopted a qualitative scoring method for the pentagon copy test (QSPT) which categorizes different possible errors in copying rather than the dichotomous categories "correct" or "incorrect." We correlated (regional) gray matter volumes with performance on the different categories of the QSPT. Results showed that the total score of the QSPT was specifically associated with parietal gray matter volume and not with frontal, temporal, and occipital gray matter volume. A more fine-grained analysis of the errors reveals that the intersection score and the number of angles share their underlying neural correlates and are associated with specific subregions of the parietal cortex. These results are in line with the idea that constructional apraxia can be attributed to the failure to integrate visual information correctly from one fixation to the next, a process called spatial remapping.

Differentiation of neuropsychological features between posterior cortical atrophy and early onset Alzheimer's disease

Background

Posterior cortical atrophy (PCA) is a group of clinical syndromes characterized by visuospatial and visuoperceptual impairment, with memory relatively preserved. Although PCA is pathologically almost identical to Alzheimer’s disease (AD), they have different cognitive features. Those differences have only rarely been reported in any Chinese population. The purpose of the study is to establish neuropsychological tests that distinguish the clinical features of PCA from early onset AD (EOAD).

Methods

Twenty-one PCA patients, 20 EOAD patients, and 20 healthy controls participated in this study. Patients had disease duration of ≤4 years. All participants completed a series of neuropsychological tests to evaluate their visuospatial, visuoperceptual, visuo-constructive, language, executive function, memory, calculation, writing, and reading abilities. The cognitive features of PCA and EOAD were compared.

Results

All the neuropsychological test scores showed that both the PCA and EOAD patients were significantly more impaired than people in the control group. However, PCA patients were significantly more impaired than EOAD patients in visuospatial, visuoperceptual, and visuo-constructive function, as well as in handwriting, and reading Chinese characters.

Conclusions

The profile of neuropsychological test results highlights cognitive features that differ between PCA and EOAD. One surprising result is that the two syndromes could be distinguished by patients’ ability to read and write Chinese characters. Tests based on these characteristics could therefore form a brief PCA neuropsychological examination that would improve the diagnosis of PCA.

The Closing-In Phenomenon in an Ecological Walking Task

OBJECTIVES

Alzheimer's disease (AD) patients may show the Closing-in (CI), a tendency to reproduce figures close to or superimposed on the model. AD patients with CI might manifest reduced functional independence compared to AD patients without CI, but no study directly assessed if CI can hamper common daily living activities. To address this issue here we investigated whether AD patients with CI veer their walking trajectory toward irrelevant objects more often than AD patients without CI.

METHODS

Fifty AD individuals, and 20 age- and education-matched healthy adults, underwent a graphic copying task to detect CI and a newly developed walking task to assess the tendency to veer toward irrelevant objects and to bump into them. All participants also completed a comprehensive neuropsychological battery to assess dementia severity; impairments in frontal/executive, visuo-spatial, visuo-constructional, and memory domains; and functional independence in daily living activities.

RESULTS

Graphic CI occurred in 34/50 (68%) AD patients (AD-CI group) who achieved significantly lower scores on frontal/executive abilities, and daily living functioning than AD individuals not showing CI. Most AD-CI patients (20/34; 58.8%) also showed at least one veering error in the walking task. Participants with CI and veering errors showed significantly poorer performance on Stroop test, and lower level of functional independence than AD individuals with CI in isolation.

CONCLUSIONS

CI on graphic tasks can identify difficulties in walking and in complying with everyday activities in AD patients. These observations demonstrate the value of assessing CI in copying tasks. (JINS, 2018, 24, 437-444).

Qualitative Analysis of Mini Mental State Examination Pentagon in Vascular Dementia and Alzheimer's Disease: A Longitudinal Explorative Study

BACKGROUND

Vascular dementia and Alzheimer's disease are the most diffuse forms of dementia. Sometimes, they are difficult to distinguish due to overlaps in symptomatology, pathophysiology, and comorbidity. Visual constructive apraxia is very common in dementia and impairment in these abilities can provide clinical information for differential diagnosis.

MATERIALS AND METHODS

All patients underwent Mini Mental State Examination (MMSE) at basal visit (T0) and after 1 year (T1). We analyzed differences in Qualitative Scoring Method for the Pentagon Copying Test and we explored the visual constructive apraxia evolution in these 2 types of dementia.

RESULTS

In intragroup analysis, we found a significant difference in each group between T0 and T1 in MMSE score (P < .001) and total qualitative scores (P < .001). In intergroup analysis, at T0, we found significance difference in total qualitative scores (P < .001), in numbers of angles (P = .005), in distance/intersection (P < .001), in closure/opening (P = .01), in rotation (P < .001), and in closing-in (P < .001). At T1, we found significance difference in total qualitative scores (P < .001), in particular, in numbers of angles (P < .001), in distance/intersection (P < .001), in closure/opening (P < .001), in rotation (P < .001), and in closing-in (P < .001). The total score showed the highest classification accuracy (.90, 95%CI = .81-0.96) in differentiating patients with Alzheimer's disease from patients with vascular dementia. The optimal threshold value was k = 5. with .84 (95%CI = .69-0.93) sensitivity and .81 (95%CI = .64-0.93) specificity.

CONCLUSION

Patients with vascular dementia showed more accuracy errors and graphic difficulties than patients with Alzheimer's disease. Qualitative analysis of copy provided a sensitive measure of visual constructive abilities in differentiating dementias, underlining a particularly vulnerability of visuoconstructive functions in vascular dementia compared with Alzheimer's disease.

Constructional apraxia

Since the classic papers of Kleist, Mayer Gross, and Critchley, constructional apraxia (CA) has been considered to be a typical sign of a parietal lobe lesion, and as a precious tool to appreciate the spatial abilities subserved by this lobe. However, the development of more sophisticated neuropsychologic models and methods of investigation has revealed several problematic aspects. It has become increasingly clear that CA is a heterogeneous construct that can be examined with very different tasks, that are only mildly interconnected, and tap various kinds of visuospatial, perceptual, attentional, planning, and motor mechanisms. On the basis of these considerations, the relationships between parietal lobe functions and constructional activities must be considered, taking into account on the one hand the heterogeneity of the tasks and of the cognitive functions requested by different kinds of constructional activities and, on the other hand, the plurality of functions and of processing streams linking different parts of the parietal lobes to the occipital and frontal lobes.

Cognitive and behavioral disorders in Parkinson's disease: an update. I: cognitive impairments

Parkinson's disease (PD) is a progressive neurodegenerative disease characterized by motor symptoms such as rigidity, rest tremor, and bradykinesia. However, a growing body of evidence demonstrated that PD encompasses several non-motor disturbances as well, such as cognitive impairment. Cognitive defects can be present since early stages of the disease but tend to dominate the clinical picture as the disease progresses. Around 40% of patients with PD present with cognitive impairments in several cognitive domains including attention, working memory and executive functions, language, visuospatial skills, and episodic memory; in later stages of the disease, cognitive defects and associated behavioral disorders concur to determine clinically relevant PD-associated dementia. Part of these defects is ascribed to a dopamine-dependent dysfunction of fronto-striatal pathways, but there is a considerable heterogeneity in the cognitive impairments as well as a suggestion of the role of other neurotransmitter systems, such as the cholinergic one, mainly responsible for Parkinson-dementia syndrome. In this paper, we review recent literature with particular attention to the last 5 years on the main cognitive deficits described in PD patients as well as on the hypothesized neuro-functional substrate of such impairments. Finally, we provide some suggestions on how to test cognitive functions in PD appropriately.

Changes in Tryptophan Catabolite (TRYCAT) Pathway Patterning Are Associated with Mild Impairments in Declarative Memory in Schizophrenia and Deficits in Semantic and Episodic Memory Coupled with Increased False-Memory Creation in Deficit Schizophrenia

Evidence indicates that schizophrenia and in particular negative symptoms and deficit schizophrenia are accompanied by neurocognitive impairments and changes in the patterning of the tryptophan catabolite (TRYCAT) pathway. This cross-sectional study was carried out to examine the associations between cognitive functions (as measured with Consortium to Establish a Registry for Alzheimer's disease (CERAD)) and TRYCAT pathway patterning in patients with (n = 40) and without (n = 40) deficit schizophrenia and normal controls (n = 40). Cognitive measures were assessed with the Verbal Fluency Test (VFT), Boston Naming Test (BNT), Mini-Mental State Examination (MMSE), Word List Memory (WLM), Constructional Praxis, Word List Recall (WLRecall), and Word List Recognition (WLRecognition), while TRYCAT measurements assessed the IgA/IgM responses to noxious TRYCATs, namely quinolinic acid (QA), 3-OH-kynurenine (3HK), picolinic acid (PA), and xanthurenic (XA) acid, and more protective (PRO) TRYCATs, including kynurenic acid (KA) and anthranilic acid (AA). IgA NOX/PRO, IgM KA/3HK, and IgA/IgM NOX/PRO ratios were computed. Schizophrenia was accompanied by lower VFT and WLM, while BNT (dysnomia) and MMSE are significantly lower in multiple- than first-episode schizophrenia. Deficit schizophrenia is strongly associated with worse outcomes on VFT, MMSE, WLM, WLRecall, WLRecognition, and delayed recall savings and increased false memories. Around 40-50% of the variance in negative symptoms' scores was explained by VFT, WLM, WLRecall, and MMSE. Increases in IgA NOX/PRO, IgM KA/3HK, and/or IgA/IgM NOX/PRO ratios were associated with impairments in VFT, BNT, MMSE, WLM, WLRecall, WLRecognition, and false-memory creation. In conclusion, nondeficit schizophrenia is accompanied by mild memory impairments, while disease progression is accompanied by broader cognitive impairments. Deficit schizophrenia and negative symptoms are strongly associated with deficits in working memory, delayed recall and recognition, and increased false-memory creation. These cognitive impairments and memory deficits are in part explained by increased production and/or attenuated regulation of TRYCATs with neurotoxic, excitotoxic, immune-inflammatory, oxidative, and nitrosative potential, which may contribute to neuroprogression.