In recent years, the focus of research on Alzheimer's disease (AD) has shifted toward finding reliable diagnostic biomarkers that enable accurate detection of mild cognitive impairment (MCI) as well as AD. Functional magnetic resonance imaging (fMRI) has the potential to identify functional changes in the preclinical stages of AD. In addition to the cardinal deficits in memory, deficits in visuospatial cognition are pervasive in AD. Recent neurophysiological and imaging studies have revealed that changes in visuospatial perception (VSP) functions can be detected in the early stages of AD. This review highlights the scope of VSP functional alterations as a biomarker for AD. We describe the neuroanatomical regions involved in the processing of various VSP tasks, and discuss the effect of AD on these regions from a pathological as well as a functional point of view. A comprehensive synopsis of the existing fMRI literature that has assessed VSP in patients with MCI and AD has been provided. The diagnostic scope of monitoring the brain activation correlates of VSP processing in AD is discussed in terms of the key advantages of utilizing VSP-related deficits in AD for early detection and longitudinal tracking of AD.
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http://dx.doi.org/10.3233/JAD-2012-120901 | DOI Listing |
Alzheimers Dement
December 2024
Dementia Research Centre, Queen Square Institute of Neurology, University College London, London, United Kingdom.
Background: Primary Progressive Aphasia (PPA) is a neurodegenerative disorder primarily affecting language abilities, with clinical variants (nonfluent/agrammatic variant [nfvPPA], semantic variant [svPPA], logopenic variant [lvPPA], and mixed-PPA [mPPA]) categorized based on linguistic features. This study aims to compare PPA cohorts of native speakers of two different languages: English (an analytic language with deep orthography) and Italian (a synthetic language with shallow orthography).
Methods: We considered 166 English participants (70 nfvPPA, 45 svPPA, 42 lvPPA, 9 mPPA) and 106 Italian participants (14 nfvPPA, 20 svPPA, 42 lvPPA, 31 mPPA).
Alzheimers Dement
December 2024
Frontotemporal Disorders Unit, Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
Background: Posterior Cortical Atrophy (PCA) is a syndrome characterized by a progressive decline in higher-order visuospatial processing, leading to symptoms such as space perception deficit, simultanagnosia, and object perception impairment. While PCA is primarily known for its impact on visuospatial abilities, recent studies have documented language abnormalities in PCA patients. This study aims to delineate the nature and origin of language impairments in PCA, hypothesizing that language deficits reflect the visuospatial processing impairments of the disease.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore, Singapore.
Background: The Visual Cognitive Assessment Test (VCAT) is a visual based, language neutral cognitive assessment validated across cultures and ethnicities, that allows for early diagnosis of cognitive impairment. The VCAT assess domains of cognition - Memory, Visuospatial function, attention, language and Executive function. The Mild Behavioural Impairment Checklist (MBI-C) was developed to assess five domains of NPS - Decreased motivation, emotional dysregulation, impulse control, social inappropriateness and abnormal beliefs/perceptions Current research indicates an association between MBI symptom severity and poorer cognitive performance in the domains of memory.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Centre for Brain Research, Indian Institute of Science, Bangalore, Karnataka, India.
Background: Refractive errors are common visual comorbidities among the elderly. Cognitive dysfunction also occurs in this population. A study by Ong et al (2013) demonstrated an association of refractive errors with poor cognitive performance.
View Article and Find Full Text PDFAlzheimers Dement
December 2024
Centre for Brain Research, Indian Institute of Science, Bangalore, Karnataka, India.
Background: Visuo-cognitive skills represent a network of different abilities that rely on vision and cognition. While visuo-cognitive abilities have been considered prominent indicators of dementia, there is a dearth of studies that profile these abilities with demographic correlates in an aging Indian population. Investigating the pattern of visuo-cognitive abilities is essential to facilitate early indication, better prognosis and treatment of symptoms.
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