Real-space navigation testing differentiates between amyloid-positive and -negative aMCI

ObjectiveTo distinguish between patients with amyloid-positive (A+) and -negative (A−) amnestic mild cognitive impairment (aMCI) by simultaneously investigating navigation performance, visual exploration behavior, and brain activations during a real-space navigation paradigm.MethodsTwenty-one patients with aMCI were grouped into A+ (n = 11) and A− cases by amyloid-PET imaging and amyloid CSF levels and compared to 15 healthy controls. Neuropsychological deficits were quantified by use of the Consortium to Establish a Registry for Alzheimer's Disease–plus cognitive battery. All participants performed a navigation task in which they had to find items in a realistic spatial environment and had to apply egocentric and allocentric route planning strategies. 18F-fluorodeoxyglucose was injected at the start to detect navigation-induced brain activations. Subjects wore a gaze-controlled, head-fixed camera that recorded their visual exploration behavior.ResultsA+ patients performed worse during egocentric and allocentric navigation compared to A− patients and controls (p < 0.001). Both aMCI subgroups used fewer shortcuts, moved more slowly, and stayed longer at crossings. Word-list learning, figural learning, and Trail-Making tests did not differ in the A+ and A− subgroups. A+ patients showed a reduced activation of the right hippocampus, retrosplenial, and parietal cortex during navigation compared to A− patients (p < 0.005).ConclusionsA+ patients with aMCI perform worse than A− patients with aMCI in egocentric and allocentric route planning because of a more widespread impairment of their cerebral navigation network. Navigation testing in real space is a promising approach to identify patients with aMCI with underlying Alzheimer pathology.

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Prolonged allocentric navigation deficits indicate hippocampal damage in TGA

Neurology ◽

10.1212/wnl.0000000000006779 ◽

2018 ◽

Vol 92 (3) ◽

pp. e234-e243 ◽

Cited By ~ 3

Author(s):

Florian Schöberl ◽

Stephanie Irving ◽

Cauchy Pradhan ◽

Stanislavs Bardins ◽

Christoph Trapp ◽

...

Keyword(s):

Spatial Orientation ◽

Route Planning ◽

Transient Global Amnesia ◽

Complete Recovery ◽

Real Space ◽

Error Rates ◽

Visual Exploration ◽

Hippocampal Damage ◽

Network Function

ObjectiveTo investigate long-term recovery of allocentric and egocentric spatial orientation as a sensitive marker for hippocampal and extrahippocampal network function in transient global amnesia (TGA).MethodsA group of 18 patients with TGA performed an established real-space navigation paradigm, requiring allo- and egocentric spatial orientation abilities, 3 days (postacute stage) and 3 months (follow-up) after symptom onset. Visual exploration behavior and navigation strategy were documented by a gaze-controlled, head-fixed camera. Allo- and egocentric spatial orientation performance was compared to that of 12 age-matched healthy controls. Navigation-induced brain activations were measured using [18F]-fluorodeoxyglucose-PET in a subgroup of 8 patients in the postacute stage and compared to those of the controls.ResultsIn the postacute stage, the patients navigated worse and had higher error rates than controls in allocentric (p = 0.002), but not in egocentric, route planning (p = 0.30), despite complete recovery of verbal (p = 0.58) and figural memory (p = 0.11). Until follow-up, allocentric navigation deficits improved, but higher error rates and reduced use of shortcuts persisted (p < 0.0001). Patients still exhibited relatively more fixations of unique landmarks during follow-up (p = 0.05). PET measurements during the postacute stage showed increased navigation-induced brain activations in the right hippocampus, bilateral retrosplenial, parietal, and mesiofrontal cortices, and cerebellar dentate nucleus in patients compared to controls (p < 0.005).ConclusionsPatients with TGA show selective and prolonged deficits of allocentric spatial orientation. Activations in right hippocampal and extrahippocampal hubs of the cerebral navigation network functionally substitute for the deficit in creating and updating the internal cognitive map in TGA.

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Bilateral vestibulopathy causes selective deficits in recombining novel routes in real space

Scientific Reports ◽

10.1038/s41598-021-82427-6 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Florian Schöberl ◽

Cauchy Pradhan ◽

Maximilian Grosch ◽

Matthias Brendel ◽

Florian Jostes ◽

...

Keyword(s):

Vestibular Function ◽

Real Space ◽

Brain Network ◽

Retrosplenial Cortex ◽

Visual Exploration ◽

Bilateral Vestibulopathy ◽

Anterior Thalamus ◽

Brain Activation Pattern ◽

The Right ◽

Parahippocampal Place Area

AbstractThe differential impact of complete and incomplete bilateral vestibulopathy (BVP) on spatial orientation, visual exploration, and navigation-induced brain network activations is still under debate. In this study, 14 BVP patients (6 complete, 8 incomplete) and 14 age-matched healthy controls performed a navigation task requiring them to retrace familiar routes and recombine novel routes to find five items in real space. [18F]-fluorodeoxyglucose-PET was used to determine navigation-induced brain activations. Participants wore a gaze-controlled, head-fixed camera that recorded their visual exploration behaviour. Patients performed worse, when recombining novel routes (p < 0.001), whereas retracing of familiar routes was normal (p = 0.82). These deficits correlated with the severity of BVP. Patients exhibited higher gait fluctuations, spent less time at crossroads, and used a possible shortcut less often (p < 0.05). The right hippocampus and entorhinal cortex were less active and the bilateral parahippocampal place area more active during navigation in patients. Complete BVP showed reduced activations in the pontine brainstem, anterior thalamus, posterior insular, and retrosplenial cortex compared to incomplete BVP. The navigation-induced brain activation pattern in BVP is compatible with deficits in creating a mental representation of a novel environment. Residual vestibular function allows recruitment of brain areas involved in head direction signalling to support navigation.

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The expressivity dimension of speech is the basis of the expression dimension. Evidence from behavioural and neuroimaging studies

10.31234/osf.io/8p7tr ◽

2020 ◽

Author(s):

Isabelle Hesling

Keyword(s):

Language Acquisition ◽

Experimental Psychology ◽

Right Hemisphere ◽

Word List ◽

Behavioral Experiments ◽

Brain Areas ◽

Language Communication ◽

Neuroimaging Data ◽

List Processing ◽

The Right

The modalities of communication are the sum of the expression dimension (linguistics) and the expressivity dimension (prosody), both being equally important in language communication. The expressivity dimension which comes first in the act of speech, is the basis on which phonemes, syllables, words, grammar and morphosyntax, i.e., the expression dimension of speech is superimposed. We will review evidence (1) revealing the importance of prosody in language acquisition and (2) showing that prosody triggers the involvement of specific brain areas dedicated to sentences and word-list processing. To support the first point, we will not only rely on experimental psychology studies conducted in newborns and young children but also on neuroimaging studies that have helped to validate these behavioral experiments. Then, neuroimaging data on adults will allow for concluding that the expressivity dimension of speech modulates both the right hemisphere prosodic areas and the left hemisphere network in charge of the expression dimension

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Baseline Cognitive Impairment in Patients With Asymptomatic Carotid Stenosis in the CREST-2 Trial

Stroke ◽

10.1161/strokeaha.120.032972 ◽

2021 ◽

Author(s):

Ronald M. Lazar ◽

Virginia G. Wadley ◽

Terina Myers ◽

Michael R. Jones ◽

Donald V. Heck ◽

...

Keyword(s):

Cognitive Impairment ◽

Carotid Stenosis ◽

Racial Differences ◽

Carotid Artery Disease ◽

Word List ◽

Population Based ◽

Asymptomatic Carotid Stenosis ◽

Carotid Disease ◽

Asymptomatic Carotid ◽

List Learning

Background and Purpose: Studies of carotid artery disease have suggested that high-grade stenosis can affect cognition, even without stroke. The presence and degree of cognitive impairment in such patients have not been reported and compared with a demographically matched population-based cohort. Methods: We studied cognition in 1000 consecutive CREST-2 (Carotid Revascularization and Medical Management for Asymptomatic Carotid Stenosis Trial) patients, a treatment trial for asymptomatic carotid disease. Cognitive assessment was after randomization but before assigned treatment. The cognitive battery was developed in the general population REGARDS Study (Reasons for Geographic and Racial Differences in Stroke), involving Word List Learning Sum, Word List Recall, and Word List fluency for animal names and the letter F. The carotid stenosis patients were >45 years old with ≥70% asymptomatic carotid stenosis and no history of prevalent stroke. The distribution of cognitive performance for the patients was standardized, accounting for age, race, and education using performance from REGARDS, and after further adjustment for hypertension, diabetes, dyslipidemia, and smoking. Using the Wald Test, we tabulated the proportion of Z scores less than the anticipated deviate for the population-based cohort for representative percentiles. Results: There were 786 baseline assessments. Mean age was 70 years, 58% men, and 52% right-sided stenosis. The overall Z score for patients was significantly below expected for higher percentiles ( P <0.0001 for 50th, 75th, and 95th percentiles) and marginally below expected for the 25th percentile ( P =0.015). Lower performance was attributed largely to Word List Recall ( P <0.0001 for all percentiles) and for Word List Learning (50th, 75th, and 95th percentiles below expected, P ≤0.01). The scores for left versus right carotid disease were similar. Conclusions: Baseline cognition of patients with severe carotid stenosis showed below normal cognition compared to the population-based cohort, controlling for demographic and cardiovascular risk factors. This cohort represents the largest group to date to demonstrate that poorer cognition, especially memory, in this disease. REGISTRATION: URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02089217.

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Examining Sex Differences in Markers of Cognition and Neurodegeneration in Autosomal Dominant Alzheimer’s Disease: Preliminary Findings from the Colombian Alzheimer’s Prevention Initiative Biomarker Study

Journal of Alzheimer s Disease ◽

10.3233/jad-200723 ◽

2020 ◽

Vol 77 (4) ◽

pp. 1743-1753

Author(s):

Clara Vila-Castelar ◽

Edmarie Guzmán-Vélez ◽

Enmanuelle Pardilla-Delgado ◽

Rachel F. Buckley ◽

Yamile Bocanegra ◽

...

Keyword(s):

Alzheimer’S Disease ◽

Sex Differences ◽

Autosomal Dominant ◽

Volume Ratio ◽

Word List ◽

Hippocampal Volume ◽

Delayed Recall ◽

List Learning ◽

Age Range ◽

Female Carriers

Background: Growing evidence suggests that there may be a sex-specific biological risk for Alzheimer’s disease (AD). Individuals with autosomal dominant AD due to a mutation (E280A) in Presenilin-1 (PSEN1) are genetically determined to develop early-onset dementia and thus, have few age-related risk factors for AD that are known to vary by sex (i.e., cardiovascular disease, menopause, life expectancy). Objective: Investigate sex differences in markers of cognition and neurodegeneration in autosomal dominant AD. Methods: We conducted a retrospective study in 19 cognitively-unimpaired PSEN1 mutation carriers (age range 20–44; 11 females), 11 symptomatic carriers (age range 42–56; 8 females), and 23 matched non-carriers family members (age range 20–50; 13 females). We examined hippocampal volume ratio, CERAD Total Score, and CERAD Word List (i.e., Learning, Delayed Recall, and Recognition). Mann-Whitney U tests, Spearman correlations and regression models were conducted. Results: There were no differential associations between age, CERAD Total Score, CERAD Word List–Learning, Delayed Recall, Recognition, and hippocampal volume ratio in male and female carriers and non-carriers. Cognitively-unimpaired female carriers showed better CERAD Total scores and CERAD Word List-Learning than cognitively-unimpaired male carriers, despite having similar hippocampal volume ratios. The interaction of sex and hippocampal volume ratio did not predict cognitive performance across groups. Conclusion: Our preliminary findings suggest that cognitively-unimpaired female carriers showed a verbal memory reserve, and as disease progresses, female carriers did not exhibit a cognitive susceptibility to AD-related neurodegeneration. Future studies with larger samples of autosomal dominant AD are warranted to further understand sex differences in AD-related clinical and pathological markers.

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