Ho Yan Lai, Andi Tri Supratno Musrah, Kah Hui Yap, Yong En Chow, Naaz Salim, Noor Shatirah Voon
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引用次数: 0
Abstract
Background: Alzheimer's disease (AD) exhibits distinct visuospatial impairments across its clinical subtypes, including typical amnestic AD and posterior cortical atrophy (PCA). Resting-state functional MRI (rs-fMRI) reveals disruptions in large-scale brain networks, yet the relationship between connectivity alterations and visuospatial deficits remains unclear.
Objective: We investigated visuospatial deficits across AD subtypes and identified affected brain networks to inform clinical interventions.
Methods: Six studies were reviewed by comparing visuospatial performance and rs-fMRI-derived functional connectivity in AD and healthy controls (HC). Effect sizes (Bonett's δ) for behavioral tasks and correlation coefficients (r) for imaging-clinical associations were synthesized.
Results: Patients with AD exhibited significant visuospatial deficits, with moderate to large effect sizes in amnestic AD (δ = 1.0-1.5) and severe impairments in PCA (δ ≥ 3.0). Rs-fMRI revealed disrupted connectivity in three key networks: dorsal parietal-occipital networks (strongly linked to visuospatial deficits, especially in PCA), default mode network (DMN) (associated with memory but indirectly contributing to visual integration), and cerebellar-cortical circuits (implicated in early AD). Moderate correlations (r = 0.33-0.44, p < 0.05) were found between connectivity loss (DMN, cerebellar) and poor Rey-Osterrieth Complex Figure (ROCF) performance. However, some studies reported null associations, possibly due to compensatory mechanisms or methodological heterogeneity.
Conclusion: AD subtypes exhibit distinct network dysfunction patterns, with PCA showing severe posterior network disruption and amnestic AD involving broader DMN and cerebellar degeneration. Rs-fMRI provides valuable insights into the neural basis of visuospatial deficits, suggesting potential biomarkers for subtype-specific diagnosis and intervention.
期刊介绍:
Behavioural Brain Research is an international, interdisciplinary journal dedicated to the publication of articles in the field of behavioural neuroscience, broadly defined. Contributions from the entire range of disciplines that comprise the neurosciences, behavioural sciences or cognitive sciences are appropriate, as long as the goal is to delineate the neural mechanisms underlying behaviour. Thus, studies may range from neurophysiological, neuroanatomical, neurochemical or neuropharmacological analysis of brain-behaviour relations, including the use of molecular genetic or behavioural genetic approaches, to studies that involve the use of brain imaging techniques, to neuroethological studies. Reports of original research, of major methodological advances, or of novel conceptual approaches are all encouraged. The journal will also consider critical reviews on selected topics.