Editorial: Psychology and Neuropsychology of Perception, Action, and Cognition

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The impact of brain lesion characteristics and the corticospinal tract wiring on mirror movements in unilateral cerebral palsy.

Mirror movements (MM) influence bimanual performance in children with unilateral cerebral palsy (uCP). Whilst MM are related to brain lesion characteristics and the corticospinal tract (CST) wiring pattern, the combined impact of these neurological factors remains unknown. Forty-nine children with uCP (mean age 10y6mo) performed a repetitive squeezing task to quantify similarity (MM-similarity) and strength (MM-intensity) of the MM activity. We used MRI data to evaluate lesion type (periventricular white matter, N = 30; cortico-subcortical, N = 19), extent of ipsilesional damage, presence of bilateral lesions, and damage to basal ganglia, thalamus and corpus callosum. The CST wiring was assessed with Transcranial Magnetic Stimulation (17 CSTcontralateral, 16 CSTipsilateral, 16 CSTbilateral). Data was analyzed with regression analyses. In the more-affected hand, MM-similarity and intensity were higher with CSTbilateral/ipsilateral. In the less-affected hand, MM-similarity was higher in children with (1) CSTcontra with CSC lesions, (2) CSTbilat/ipsi with PVL lesions and (3) CSTbilat/ipsi with unilateralized lesions. MM-intensity was higher with larger damage to the corpus callosum and unilateral lesions. A complex combination of neurological factors influences MM characteristics, and the mechanisms differ between hands

CEREBRAL VISUAL IMPAIRMENT Clinical and Radiological Measures With an emphasis on ventral stream functions

status: publishe

Low vision affects dynamic stability of gait

The objective of this study was to demonstrate specific differences in gait patterns between those with and without a visual impairment. We performed a biomechanical analysis of the gait pattern of young adults (27±13 years old) with a visual impairment (n=10) in an uncluttered environment and compared it to the gait pattern of age matched controls (n=20). Normally sighted adults were tested in a full vision and no vision condition. Differences are found in gait between both groups and both situations. Adults with a visual impairment walked with a shorter stride length (1.14±0.21m), less trunk flexion (4.55±5.14°) and an earlier plantar foot contact at heel strike (1.83±3.49°) than sighted individuals (1.39±0.08m; 11.07±4.01°; 5.10±3.53°). When sighted individuals were blindfolded (no vision condition) they showed similar gait adaptations as well as a slower walking speed (0.84±0.28ms -1), a lower cadence (96.88±13.71stepsmin -1) and limited movements of the hip (38.24±6.27°) and the ankle in the saggital plane (-5.60±5.07°) compared to a full vision condition (1.27±0.13ms -1; 110.55±7.09stepsmin -1; 45.32±4.57°; -16.51±6.59°).Results showed that even in an uncluttered environment vision is important for locomotion control. The differences between those with and without a visual impairment, and between the full vision and no vision conditions, may reflect a more cautious walking strategy and adaptive changes employed to use the foot to probe the ground for haptic exploration. © 2010 Elsevier B.V.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Development of independent locomotion in children with a severe visual impairment

Locomotion of children and adults with a visual impairment (ages 1-44, n=28) was compared to that of age-related individuals with normal vision (n=60). Participants walked barefoot at preferred speed while their gait was recorded by a Vicon ® system. Walking speed, heading angle, step frequency, stride length, step width, stance phase duration and double support time were determined. Differences between groups, relationships with age and possible interaction effects were investigated. With increasing age overall improvements in gait parameters are observed. Differences between groups were a slower walking speed, a shorter stride length, a prolonged duration of stance and of double support in the individuals with a visual impairment. These may be considered either as adaptations to balance problems or as strategies to allow to foot to probe the ground. © 2011 Elsevier Ltd.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

G.CVI.Tods, a novel diagnostic tool in the assessment of Cerebral Visual Impairment in the young child

status: publishe