Neuronal Control of Posture in Blind Individuals.

The control of posture is guided by the integration of sensory information. Because blind individuals cannot apply visual information to control posture as sighted individuals do they must compensate by the remaining senses. We therefore hypothesize that blind individuals alter their brain activation in the sensorimotor cortex during postural control to compensate for balance control without vision by the increased integration of somatosensory information. Ten blind and ten sighted (matched) individuals controlled posture during conditions with (I) eyes closed / open, and (II) stable / unstable surface conditions. Postural sway was recorded by applying a pressure distribution measuring plate. Brain activation was collected by functional Near InfraRed Spectroscopy (fNIRS) above motor-sensory cortices of the right and left hemispheres. Blind individuals showed significantly increased postural sway when balancing with open eyes on an unstable surface and when compared to sighted individuals. Whereas blind individuals showed significantly increased brain activation when balancing with open eyes on stable and unstable surface conditions, sighted individuals increased their brain oxygenation only during closed eyes and unstable surface conditions. Overall conditions, blind individuals presented significantly increased brain activation in two channels of the left and right hemispheric motor-sensory cortex when compared to sighted individuals. We therefore conclude that sighted individuals increase their brain oxygenation in the sensorimotor cortex during postural control tasks that demand sensory integration processes. Blind individuals are characterized by increased brain activation overall conditions indicating additional sensory integration during postural control. Thus, the sensorimotor cortex of blind individuals adapts to control posture without vision.

Neurobehavioral consequences of repetitive head impacts in Para swimming: A case report.

Para swimmers with limb deficiency are faced with the particular situation that they must use their head to finish each competition by a hit to the wall. Repetitive head impacts may impair behavioral and brain functions. We therefore investigated neurobehavioral functions of a Para swimmer with dysmelia before and after repetitive head impacts (T1) and without (T2). Average head impact at T1 constituted 13.6 g with a mean impact force of 6689.9 N. Behavioral and brain functions decreased from pre to post at T1 but not at T2. Para swimmers with limb deficiency are therefore affected from the same consequences onto brain health that are observed after repeated sport-related concussions.