The visual cortex and visual cognition in Huntington’s disease: An overview of current literature

Abstract

The processing of visual stimuli from retina to higher cortical areas has been extensively studied in the human brain. In Huntington's disease (HD), an inherited neurodegenerative disorder, it is suggested that visual processing deficits are present in addition to more characteristic signs such as motor disturbances, cognitive dysfunction, and behavioral changes. Visual deficits are clinically important because they influence overall cognitive performance and have implications for daily functioning. The aim of this review is to summarize current literature on clinical visual deficits, visual cognitive impairment, and underlying visual cortical changes in HD patients. A literature search was conducted using the electronic database of PubMed/Medline. This review shows that changes of the visual system in patients with HD were not the primary focus of currently published studies. Still, early atrophy and alterations of the posterior cerebral cortex was frequently observed, primarily in the associative visual cortical areas such as the lingual and fusiform gyri, and lateral occipital cortex. Changes were even present in the premanifest phase, before clinical onset of motor symptoms, suggesting a primary region for cortical degeneration in HD. Although impairments in visuospatial processing and visual perception were reported in early disease stages, heterogeneous cognitive batteries were used, making a direct comparison between studies difficult. The use of a standardized battery of visual cognitive tasks might therefore provide more detailed information regarding the extent of impairments in specific visual domains. Further research could provide more insight into clinical, functional, and pathophysiological changes of the visual pathway in HD.

Dynamic functional network connectivity in Huntington's disease and its associations with motor and cognitive measures

“…Occipital atrophy has also been associated with poorer visuospatial or cognitive performance (Johnson et al, ; Labuschagne et al, ; Tabrizi et al, ). In contrast, few fMRI studies have reported occipital functional alterations and results are not conclusive, as reviewed by Coppen et al (). Our study of a relatively large rs‐fMRI sample, focused on the unrestricted analysis of whole brain dynamic functional connectivity, complements, and extends previous work demonstrating that functional connectivity in the SC (putamen), SM, DMN, VIS, and cognitive domains is affected in premanifest HD and early‐stage individuals.…”

“…Alterations of visual cortex and visual cognition, though not the primary focus of HD studies, have been frequently observed (Dumas et al, ). As reviewed by Coppen, van der Grond, Hart, Lakke, and Roos (), structural atrophy of the occipital lobe is among the most stable findings in HD brain volumetric and thickness studies, with changes in posterior occipital regions being detected as early as premanifest HD (Coppen et al, ; Johnson et al, ; Tabrizi et al, ). Occipital atrophy has also been associated with poorer visuospatial or cognitive performance (Johnson et al, ; Labuschagne et al, ; Tabrizi et al, ).…”

Impaired response of cerebral oxygen metabolism to visual stimulation in Huntington’s disease

“…In the current study, we chose to use visual stimulation because it is a simple and robust paradigm to test our methodology and because recent data and concepts indicate that more widespread areas of the brain beyond the motor circuit are affected early in HD including occipital brain regions subserving visual functions. 81…”

Emergence of Huntington Disease in a Man With a Premorbid Criminal Lifestyle

“…A phenomenon related to such violations—stalking—is described by Soliman and co-workers (9) in a woman whose unwanted surveillance of her therapist was posited to be caused by an early manifestation of basal-ganglia dysfunction in HD. Indeed, the reduced ability in sufferers of HD to recognize emotions may very well have been a contributing criminogenic factor in the present case; also, recent research has shown that HD is associated with visual-processing deficits—a phenomenon that could further compound the effects of poor emotion recognition (10). In addition, research has shown empathy deficits in HD patients, a finding consistent with an increased risk of criminality (11).…”