Visual Timing Impairments in Developmental, Acquired, and Age-Related Neurological Conditions

Timing impairments have been shown to contribute to a wide variety of neurological conditions ranging from the developmental, such as dyslexia, through the acquired, such as traumatic brain injury (TBI), to age-related diseases such as Alzheimer’s. Many have been associated with impaired development (often genetically based) or the later functioning of visual ‘magnocellular’ (timing-sensitive) neurons that dominate the input to the visual dorsal stream; this plays a major role in the direction of attention and visually guided eye and limb movements. Hence the impaired development of these neurons probably contributes greatly to dyslexics’ visual reading, attentional and working memory problems, as these all require accurate visual timing by the dorsal stream.

Likewise later, TBI or concussion may disrupt the same neural networks for attention and working memory. Thus TBI patients have longer reaction times, are more distractible, and experience difficulty in sustaining attention. In older age, the rate at which tasks can be performed (processing speed) is a robust predictor of age-related cognitive decline and an indicator in older adults that they may need help with everyday activities. Their brains’ timing functions seem to become less precise, affecting attention, attentional switching, processing speed, working memory, and multitasking. Slower processing speeds and more effortful attention have thus been found to explain a large part of age-related memory deterioration. Reduced information processing speed may also explain their problems in memory encoding and retrieval because this mental slowing can lead to superficial processing and inefficient strategies causing over recruitment of cortical areas. These age-related changes in cognition are likely to be driven by adverse changes in the connectivity of magnocellular neural timing systems.

Excitingly, this new understanding means that the operation of these systems can be improved at all ages, using a variety of techniques of which adaptive visual figure-ground movement discrimination is the most direct. As expected, this can also rehabilitate the attention and executive control networks as shown by MEG brain source imaging.

This Research Topic seeks contributions investigating the role of visual timing in detecting or improving visual and cognitive impairments at all ages, to submit papers for this collection. This approach represents a paradigm shift in screening and treatment methods. We welcome papers that relate to the hypothesis that faulty timing in synchronizing the activity of the dorsal with the ventral stream pathways may play fundamental roles in dyslexia and related neurodevelopmental conditions, such as ADHD & autism, acquired timing deficits such as TBI, and in age-related cognitive decline.

Topic Editor Teri Lawton is the CEO of Perception Dynamics Inc. All other topic editors declare no competing interests with regards to the Research Topic subject.