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Cortical Visual Loss
Published in Vivek Lal, A Clinical Approach to Neuro-Ophthalmic Disorders, 2023
This is a very rare disorder of motion perception. Only two cases have been well described, LM and AF (348–356). LM had no “impression” of motion in depth or of rapid motion, and fast-moving targets jumped rather than moved (349).
Visual changes with aging
Published in Pablo Artal, Handbook of Visual Optics, 2017
Motion perception describes the ability to detect or discriminate the motion of targets within the environment and has been studied using a wide range of approaches. Importantly, the ability to perceive motion and discriminate one’s own motion is considered to be critical for the performance of a range of everyday tasks, including driving and navigating through the environment.
Rehabilitation and management of visual dysfunction following traumatic brain injury
Published in Mark J. Ashley, David A. Hovda, Traumatic Brain Injury, 2017
There is little information on effects of brain injury on the magno pathway until it reaches the cortex. However, it is known that the large axon diameter of the magno cells makes them more vulnerable to various types of damage as in glaucoma and Alzheimer’s disease.93 Disorders of motion perception are rare.140 Indeed, studies in monkeys show that a lesion in the MT area produces disorders of motion perception, but that most of these disappear within a few days, presumably because the function is taken over by redundant pathways. Damage to the posterior cerebral cortex often results in spatial inattention to the contralateral visual field known as unilateral spatial neglect (USN) or visual–spatial neglect (VSN) discussed subsequently.
No Common Factor Underlying Decline of Visual Abilities in Mild Cognitive Impairment
Published in Experimental Aging Research, 2023
Simona Garobbio, Karin S. Pilz, Marina Kunchulia, Michael H. Herzog
As we age, perceptual and cognitive abilities decline, and in a world with an ever-increasing aging population, it is of primary interest to define visual functions that strongly relate to cognitive decline, as it may open avenues for early detection and intervention of age-related impairments (Vu et al., 2021; Zheng et al., 2018). Two predominant theories, the cascade and the common cause theory, have been proposed to explain how visual and cognitive decline may be linked (Lindenberger & Ghisletta, 2009; Pevzner, 2017; Verghese et al., 2006; Zheng et al., 2018). Here, we assessed this relationship using a battery of 19 visual tasks. We showed evidence that, on average, older adults with mild cognitive impairment perform worse in visual tasks than older adults without any evidence of cognitive decline. Importantly, we found that not only visual acuity and contrast sensitivity correlate with the cognitive state but also more complex visual functions such as orientation discrimination and motion perception. However, surprisingly, there were only weak correlations within the performances on the visual tasks in both the healthy and the MCI group.
Cognitive-Motor Interference during Dual Tasks in Blind Children
Published in Journal of Motor Behavior, 2022
Rabeb Laatar, Fatma Ben Waer, Rihab Borji, Haithem Rebai, Sonia Sahli
Postural control is the fundamental capacity to establish or restore one’s balance from any position or during any motor activity (Winter et al., 1998). It is a complex task that involves the harmonious interaction of the visual, vestibular and proprioceptive systems to maintain a good balance (Parreira et al., 2017). Visual information is one of the essential factors in the multisensory control of balance (Grace Gaerlan et al., 2012). In fact, vision is responsible for object motion perception and object recognition, as well as providing information to the brain about body position (Friedrich et al., 2008). Importantly, the visual system is the primary sensory system that allows the body to assess various external factors and to adjust the posture accordingly (Cascio, 2010; Roth, 2009).
RE: Kim Leigh N., et al. Pilot study: The Queen Square Screening Test for Visual Deficits in Dementia.
Published in Neuro-Ophthalmology, 2022
Gordon T. Plant, Merle James-Galton
The authors also imply that the test booklet was developed from the pre-existing, and fully validated, Visual Object and Space Perceptual Battery (VOSP).2 However, the overlap between the tests is modest: there are only four out of 14 tests in the booklet which are to be found in the VOSP. These four and an additional five are to be found in the Cortical Vision Screening Test (CORVIST).3 We are surprised that this test was not mentioned by the authors given that it is a more direct predecessor for the QSVD. Fraser and colleagues point out differences in cost: £244 for the VOSP as opposed to £10 for the QSVD (at “cost” with a surplus to fund new editions) and also the difference in the time taken to carry out the test (up to an hour for the VOSP and less than 10 minutes for the QSVD). The CORVIST sits nicely in the middle, costing £55 and taking around 15 minutes to complete. It is also the case that the CORVIST is now available as an on-line test whereas the QSVD is only available through the Education Department of the Institute of Neurology and was not intended for wide distribution. As an on-line test the CORVIST is being regularly updated and improved. For example, tests of motion perception will be included shortly. Income from subscriptions is used to maintain the website and carry out such developments. We emphasise that all three tests are to be used for screening; the tests are designed so that healthy subjects would make few or no errors, no scoring system is provided and if errors are made further investigation is indicated.