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.

Nonverbal hand movements serve self-related functions in blind individuals.

OBJECTIVE: Blind individuals suffer from visual (i.e., sensory) deprivation. So-called "blindisms" (or "nervous" movements) have been described as the nonverbal consequence of such deprivation. However, the neuropsychological functions of such behaviours of blind individuals have not been investigated yet. We therefore analyzed the nonverbal hand movement and gestural behaviour of blind individuals with the hypothesis that their nonverbal expressions rather serve their own mental state than the nonverbal (/gestural) depiction of (mental) images. METHODS: The (entire) nonverbal hand movement and gestural behaviour of right-handed healthy blind, (matched) sighted, and (matched) sighted/blindfolded individuals was analyzed during a standardized interview situation (about emotions and actions) by four independent (certified) raters employing the Neuropsychological Gesture (NEUROGES) Coding System. RESULTS: The results show no difference of the overall hand movement activity between blind, sighted, and sighted/blindfolded individuals. Increased position shifts and on body focused hand movements were found in blind individuals when compared to sighted and sighted/blindfolded individuals. Sighted but neither blind nor sighted/blindfolded individuals increase egocentric deictic and pantomime gestures during the re-narration of an audio story. DISCUSSION: Blind individuals seem to desynchronize during conversation (shifts), increase self-stimulation behaviour due to sensory deprivation (on body), but reduce the nonverbal transfer of mental images via hand gestures. We therefore conclude that nonverbal hand movements of blind individuals rather serve their own mental state but not for the transfer of mental images.

The pantomime of mental rotation: Left-handers are less lateralized.

INTRODUCTION: The conceptualization of skilled hand movements (praxis) may be grounded in hemispherically specialized functions. However, a left-hemispherical advantage of (tool-use) pantomime gestures and a right-hemispherical advantage of spatial gestures may be more prominent in right-handed than left-handed individuals. We therefore investigated the hypothesis that right-handed but not left-handed individuals show a superiority of the left hemisphere (/right-hand preference) for the execution of pantomime (rotation of an object) gestures as well as a right-hemispherical superiority (/left-hand preference) for gestures that depict spatial information (/positioning of an object). METHODS: 20 right- and 20 left-handed participants were asked in two experiments to demonstrate with their two hands how to move tachistoscopically (in the left (LVF) or right visual hemifields (RVF)) presented geometric objects of different rotations into an identical final position. Two independent blind raters evaluated the videotaped hand gestures employing the Neuropsychological Gesture (NEUROGES) Coding System. RESULTS: In contrast to left-handed individuals, right-handed individuals present increased pantomime - rotation gestures with the right hand and pantomime - position gestures with the left hand during stimuli presentation in either visual field. Left-handers showed significantly increased left-hand pantomime - rotation gestures during stimulus presentation within the LVF (only). DISCUSSION: Right-handed individuals increase their pantomime - rotation gestures with the right hand to depict motion but use their left hand for pantomime - position gestures to describe spatial relations of the objects. Left-handers do not show a clear lateralization of the right and left hand with regards to either handedness or hemispherically lateralized motor functions. The hemispherical lateralization of praxis functions is therefore more pronounced in right-handed than left-handed individuals.

Hemispheric specialization for nonverbal gestures depicting motion and space.

INTRODUCTION: The right hemispheric specialisation for mental rotation suggests a left hand preference for nonverbal gestures that depict spatial information. We therefore hypothesized that nonverbal depictions of spatial information are preferentially demonstrated by the left hand, i.e., are grounded in right hemispheric functions. METHODS: Right-handed participants were asked in two experiments to nonverbally demonstrate how to move tachistoscopically presented (in the left or right visual hemifields) geometric objects of different rotations into an identical final position. Two independent blind raters evaluated the videotaped hand gestures employing the Neuropsychological Gesture (NEUROGES) Coding System. RESULTS: Pantomime gestures increase in order to rotate gravitationally unstable objects whereas spatial relation presentation gestures increase when to nonverbally demonstrate a gravitationally stable object. Individuals preferred the right hand for pantomime gestures but the left hand for spatial relation presentation gestures. DISCUSSION: Individuals increase their pantomime gestures to nonverbally depict motion particularly with the right hand, i.e. the left hemisphere. In contrast, increased left hand spatial relation presentations gestures indicate that those gestures are of right hemispheric origin. Thus, the hemispherical lateralization of nonverbal gestures seems to depend on the hands' functional depiction.

Reduced frontopolar brain activation characterizes concussed athletes with balance deficits.

OBJECTIVES: Athletes with sport-related concussions (SRC) often demonstrate deficits in postural stability. Lower cerebral blood flow in frontal cortices has been documented in athletes with symptoms after SRC, however, it is unclear if functional brain oxygenation during postural control tasks is reduced in symptomatic athletes after SRC in the same manner. We therefore compared brain oxygenation patterns in frontal cortices of symptomatic and asymptomatic athletes with SRC during postural control tasks with the hypothesis that symptomatic athletes are characterized by reduced functional brain oxygenation during postural control. METHODS: 62 concussed athletes (n = 31 symptomatic, n = 31 asymptomatic) were investigated during four postural control tasks with eyes closed versus eyes opened conditions and stable vs. unstable surface conditions. Brain oxygenation was assessed using functional NearInfraRed Spectroscopy (fNIRS) on frontopolar cortices of each hemisphere. Postural sway was measured by the analysis of ground reaction forces. RESULTS: Symptomatic athletes showed greater postural sway when compared to asymptomatic athletes during postural control, particularly during closed eyes and/or unstable surface conditions. Changes of oxygenated hemoglobin (∆HbO2) within the left hemispheric frontopolar cortex were significantly reduced in symptomatic athletes when compared to asymptomatic athletes during the eyes closed condition. A stepwise linear regression analysis revealed that self-reported post-concussion symptoms such as headaches and sadness predict decreased brain oxygenation during postural control with closed eyes. CONCLUSION: Symptomatic athletes with increased postural sway are characterized by decreased frontopolar brain oxygenation during postural control tasks, particularly during conditions with closed eyes. Because the frontopolar cortex showed to be involved in redistributing executive functions to novel task situations, we conclude that athletes with post-concussion symptoms suffer from a deficit in coordinating postural adjustments to balance control tasks with reduced sensory input.

Symptoms after sport-related concussions alter gestural functions.

OBJECTIVES: Symptoms after sport-related concussions (SRC) are common. Because post-concussion symptoms are often not clearly visible, speech-accompanying gestures may help clinicians to gain additional information about the patient's history and symptoms during medical consultation. We hypothesized that athletes with SRC and who suffered from persisting symptoms would display more gestures during concussion assessment protocols when compared to non-concussed athletes because of the athletes' previous motor-sensory experiences made during the concussive event. DESIGN: A retrospective cross-sectional study. METHODS: Three matched groups of 40 (active) athletes were investigated in the context of concussion assessment (/and baseline) protocols: 14 symptomatic and 14 asymptomatic athletes with a SRC, and 12 non-concussed athletes. Certified raters using a standard analysis system for nonverbal behaviour analysed videotaped hand movements and gestures during a standardized concussion assessment protocol. RESULTS: Symptomatic athletes spent significantly more time with in space hand movements, i.e., movements that act in the body-external free space without touching anything and specifically, motion quality presentation gestures than non-concussed athletes. CONCLUSIONS: Increased in space movements, which are functionally gestures, and specifically, motion quality presentation gestures in symptomatic athletes indicate that the more vivid sensory motor experience of the head trauma is reflected in more gestural expressions. Thus, hand movements and gestures differentiate athletes who suffer from post-concussion symptoms from non-concussed athletes indicating the athletes' motor-sensory experiences of the event and its aftereffects. The present study highlights the fact that gestures can be employed as behavioural markers of symptoms after sport-related concussions.

Active assistive forced exercise provides long-term improvement to gait velocity and stride length in patients bilaterally affected by Parkinson's disease.

Forced exercise training presents a valid method of improving symptoms of Parkinson's disease such as rigor, dyskinesia and gait dysfunctions. Brain imaging data suggest that use of active assistive forced exercise could improve Parkinsonian symptoms more effectively than passive assistive forced exercise. However, the long-term effects of active versus passive assistive forced exercise on the symptoms of Parkinson's disease are unknown. Here, 24 patients showing bilateral effects of Parkinson's disease underwent a 12 week intervention of either passive or active assistive forced exercise. We analyzed tremor scores, gait patterns, and scores on the Unified Parkinson's Disease Rating Scale-III from three timepoints--before beginning the intervention, upon completion of the intervention, and twelve weeks after completion of the intervention. Participation in both passive and active assistive forced exercise increased gait velocity (0.5 km/h), swing phase (2%), monopedal stance phase (2%), elongated stride length (11 cm) and decreased double stance phase (4%). However, with participation in active assistive forced exercise, postural and kinetic tremor were also reduced and gait velocity and stride length were increased long-term. Given these findings, we conclude that future treatment for patients bilaterally affected by Parkinson's disease should carefully consider the type of assistive forced exercise intervention to be used.

Hand movements with a phase structure and gestures that depict action stem from a left hemispheric system of conceptualization.

The present study addresses the previously discussed controversy on the contribution of the right and left cerebral hemispheres to the production and conceptualization of spontaneous hand movements and gestures. Although it has been shown that each hemisphere contains the ability to produce hand movements, results of left hemispherically lateralized motor functions challenge the view of a contralateral hand movement production system. To examine hemispheric specialization in hand movement and gesture production, ten right-handed participants were tachistoscopically presented pictures of everyday life actions. The participants were asked to demonstrate with their hands, but without speaking what they had seen on the drawing. Two independent blind raters evaluated the videotaped hand movements and gestures employing the Neuropsychological Gesture Coding System. The results showed that the overall frequency of right- and left-hand movements is equal independent of stimulus lateralization. When hand movements were analyzed considering their Structure, the presentation of the action stimuli to the left hemisphere resulted in more hand movements with a phase structure than the presentation to the right hemisphere. Furthermore, the presentation to the left hemisphere resulted in more right and left-hand movements with a phase structure, whereas the presentation to the right hemisphere only increased contralateral left-hand movements with a phase structure as compared to hand movements without a phase structure. Gestures that depict action were primarily displayed in response to stimuli presented in the right visual field than in the left one. The present study shows that both hemispheres possess the faculty to produce hand movements in response to action stimuli. However, the left hemisphere dominates the production of hand movements with a phase structure and gestures that depict action. We therefore conclude that hand movements with a phase structure and gestures that represent action stem from a left hemispheric system of conceptualization.

Molecular aspects involved in swimming exercise training reducing anhedonia in a rat model of depression.

Patients suffering from depression frequently display hyperactivity of the hypothalamic-pituitary-adrenal axis (HPA) resulting in elevated cortisol levels. One main symptom of this condition is anhedonia. There is evidence that exercise training can be used as a rehabilitative intervention in the treatment of depressive disorders. In this scenario, the aim of the present study was to assess the effect of an aerobic exercise training protocol on the depressive-like behavior, anhedonia, induced by repeated dexamethasone administration. The study was carried out on adult male Wistar rats randomly divided into four groups: the "control group" (C), "exercise group" (E), "dexamethasone group" (D) and the "dexamethasone plus exercise group" (DE). The exercise training consisted of swimming (1 h/d, 5 d/wk) for 3 weeks, with an overload of 5% of the rat body weight. Every day rats were injected with either dexamethasone (D/DE) or saline solution (C/E). Proper positive controls, using fluoxetine, were run in parallel. Decreased blood corticosterone levels, reduced adrenal cholesterol synthesis and adrenal weight (HPA disruption), reduced preference for sucrose consumption and increased immobility time (depressive-like behavior), marked hippocampal DNA oxidation, increased IL-10 and total brain-derived neurotrophic factor (BDNF; pro-plus mature-forms) and a severe loss of body mass characterized the dexamethasone-treated animals. Besides increasing testosterone blood concentrations, the swim training protected depressive rats from the anhedonic state, following the same profile as fluoxetine, and also from the dexamethasone-induced impaired neurochemistry. The data indicate that physical exercise could be a useful tool in preventing and treating depressive disorders.

Muscle coordination in healthy subjects during floor walking and stair climbing in robot assisted gait training.

The aim of gait rehabilitation is a restoration of an independent gait and improvement of daily life walking functions. Therefore the specific patterns, that are to be relearned, must be practiced to stimulate the learning process of the central nervous system (CNS). The Walking Simulator HapticWalker allows for the training of arbitrary gait trajectories of daily life. To evaluate the quality of the training a total of 9 subjects were investigated during free floor walking and stair climbing and during the same tasks in two different training modes on the HapticWalker: 1) with and 2) without vertical center of mass (CoM) motion. Electromyograms (EMG) of 8 gait relevant muscles were measured and muscle activation was compared for the various training modes. Besides the muscle activation as an indicator for the quality of rehabilitation training the study investigates if a cancellation of the vertical CoM movement by adaption of the footplate trajectory is feasible i.e. the muscle activation patterns for the two training modes on the HapticWalker agree. Results show no significant differences in activation timing between the training modes. This indicates the feasibility of using a passive patient suspension and emulate the vertical CoM motion by trajectory adaption of the footplates. The muscle activation timing during HapticWalker training shows important characteristics observed in physiological free walking though a few differences can still remain.