Richard C Fitzpatrick10
Omar S Mian7
Jonathan F Marsden6
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A multiple case study was conducted in order to assess three leading theories of developmental dyslexia: (i) the phonological theory, (ii) the magnocellular (auditory and visual) theory and (iii) the cerebellar theory. Sixteen dyslexic and 16 control university students were administered a full battery of psychometric, phonological, auditory, visual and(More)
Galvanic vestibular stimulation (GVS) is a simple, safe, and specific way to elicit vestibular reflexes. Yet, despite a long history, it has only recently found popularity as a research tool and is rarely used clinically. The obstacle to advancing and exploiting GVS is that we cannot interpret the evoked responses with certainty because we do not understand(More)
Two identical stimuli, such as a pair of electrical shocks to the skin, are readily perceived as two separate events in time provided the interval between them is sufficiently long. However, as they are presented progressively closer together, there comes a point when the two separate stimuli are perceived as a single stimulus. Damage to posterior parietal(More)
Recent evidence suggests that a network of brain areas may be involved in visually guided walking. Here we study patients with Parkinson's disease (PD) who experience 'freezing' behaviour to investigate the visual control of locomotion and the role of the basal ganglia in this system. We use a variable-width doorway to measure the scaling of motor output to(More)
Passing current through mastoid electrodes (conventionally termed galvanic vestibular stimulation; GVS) evokes a balance response containing a short- and a medium-latency response. The origins of these two responses are debated. Here we test the hypotheses that they originate from net signals evoked by stimulation of otolith and semi-circular canal(More)
The vestibular system has widespread interactions with other sensory modalities. Here we investigate whether vestibular stimulation modulates somatosensory function, by assessing the ability to detect faint tactile stimuli to the fingertips of the left and right hand with or without galvanic vestibular stimulation (GVS). We found that left anodal and right(More)
Visual information modulates the balance response evoked by a pure vestibular perturbation (galvanic vestibular stimulation, GVS). Here we investigate two competing hypotheses underlying this visual-vestibular interaction. One hypothesis assumes vision acts in a feedforward manner by altering the weight of the vestibular channel of balance control. The(More)
Repetitive finger tapping is commonly used to assess bradykinesia in Parkinson's disease. The Queen Square Brain Bank diagnostic criterion of Parkinson's disease defines bradykinesia as 'slowness of initiation with progressive reduction in speed and amplitude of repetitive action'. Although progressive supranuclear palsy is considered an atypical(More)
Freezing of gait in Parkinson's disease can be difficult to study in the laboratory. Here we investigate the use of a variable-width doorway to provoke freeze behavior together with new objective methods to measure it. With this approach we compare the effects of anti-parkinsonian treatments (medications and deep-brain stimulation of the subthalamic(More)
Alignment of the body to the gravitational vertical is considered to be the key to human bipedalism. However, changes to the semicircular canals during human evolution suggest that the sense of head rotation that they provide is important for modern human bipedal locomotion. When walking, the canals signal a mix of head rotations associated with path turns,(More)