Abstract
Background: Visual perception deficits are a recurrent manifestation in Parkinson’s disease (PD). Recently, structural abnormalities of fronto-parietal areas and subcortical regions, implicated in visual stimuli analysis, have been observed in PD patients with cognitive decline and visual hallucinations. The aim of the present study was to investigate the salient aspects of visual perception in cognitively unimpaired PD patients.Methods: Eleven right-handed non-demented right-sided onset PD patients without visuospatial impairment or hallucinations and 11 healthy controls were studied with functional magnetic resonance imaging while performing a specific visuoperceptual/visuospatial paradigm that allowed to highlight the specific process underlying visuospatial judgment.Results: Significant changes in both cortical areas and subcortical regions involved in visual stimuli processing were observed. In particular, PD patients showed a reduced activation for the right insula, left putamen, bilateral caudate, and right hippocampus, as well as an over-activation of the right dorso-lateral prefrontal and of the posterior parietal cortices, particularly in the right hemisphere.Conclusions: We found that both loss of efficiency and compensatory mechanisms occur in PD patients, providing further insight into the pathophysiological role of the functional alterations of basal ganglia and limbic structures in the impairment of visuoperceptual and visuospatial functions observed in PD.
Highlights
Cognitive impairment is common in Parkinson’s disease (PD), even in the early stages, affecting around 25% of patients without dementia at the time of the diagnosis [1]
PD patients showed a reduced activation for the right insula, left putamen, bilateral caudate, and right hippocampus, as well as an over-activation of the right dorso-lateral prefrontal and of the posterior parietal cortices, in the right hemisphere. We found that both loss of efficiency and compensatory mechanisms occur in PD patients, providing further insight into the pathophysiological role of the functional alterations of basal ganglia and limbic structures in the impairment of visuoperceptual and visuospatial functions observed in PD
This study aimed to detect brain activation during a specific visuoperceptual/visuospatial task in cognitively unimpaired PD patients, compared to healthy controls, using functional magnetic resonance imaging, in order to investigate the salient aspects of the subclinical impairment of the visual perception network
Summary
Cognitive impairment is common in Parkinson’s disease (PD), even in the early stages, affecting around 25% of patients without dementia at the time of the diagnosis [1]. Cognitive changes are mainly characterized by executive, memory, and visual perception deficits [2]. Impairment in visuoperceptual abilities has been observed in object detection, categorization of visual stimuli, and face recognition [3]. It has been hypothesized that these alterations play a role in the mechanisms of pivotal motor signs of the disease, such as freezing of gait [4, 5], and are connected to the development of visual hallucinations [1, 6]. Visual perception deficits are a recurrent manifestation in Parkinson’s disease (PD). Structural abnormalities of fronto-parietal areas and subcortical regions, implicated in visual stimuli analysis, have been observed in PD patients with cognitive decline and visual hallucinations. The aim of the present study was to investigate the salient aspects of visual perception in cognitively unimpaired PD patients
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