Research into sports-related concussion (SRC) or brain injury has vastly expanded our knowledge of the connection between brain activity and behavioral outcomes. Historical examination of concussion reveals components of structural changes in the brain resulting from injury. A constellation of clinical symptoms is typically present following concussion for several days and weeks. However, the intersection of structural changes and clinical examination still remains elusive to medical professionals. With emerging technologies and modalities such as quantitative electroencephalography (EEG), functional magnetic resonance imaging (fMRI), virtual reality (VR), and the study of movement, we can better understand the brain–behavior relationship on clinical findings post-injury. Our advancement in SRC study using athletics provides a unique window into the advances in our ability to study this public health crisis. SRC also allows us to understand how athletics and exercise influence brain health. The evolution of SRC diagnosis, treatment, and management informs our current abilities in the study of the brain.
Michael Gay and Semyon Slobounov
Semyon M. Slobounov and Karl M. Newell
This study provides a comparative analysis of certain features of upright and inverted stance in collegiate-level competitive gymnastic and diving athletes. A particular focus was the compensatory movement strategies used to maintain inverted stance. The analyses revealed that the motion of the center of pressure was significantly greater in the hand stance as opposed to the upright stance condition. Instability increased over the duration of a 15-s hand stance trial, and it was paralleled by the introduction of a small set of compensatory movement strategies that included enhanced motion at the distal segments of the legs and at the elbow joint. The compensatory movement strategies appeared to be in support of minimizing variability of motion in the head and trunk. The relative contribution of the principal sources of this instability in the hand stance remains to be determined.
Semyon Slobounov, Tao Wu and Mark Hallett
Human upright posture is a product of a complex dynamic system that relies on integration of input from multimodal sensory sources. Extensive research has explored the role of visual, vestibular, and somatosensory systems in the control of upright posture. However, the role of higher cognitive function in a participant’s assessment of postural stability has been less studied. In previous research, we showed specific neural activation patterns in EEG associated with recognition of unstable postures in young healthy participants. Similar EEG patterns have been recently observed in regulation of posture equilibrium in dynamic stances. This article evaluates participants’ postural stability in dynamic stances and neural activation patterns underlying visual recognition of unstable postures using event-related functional MRI (fMRI). Our results show that the “stable” participants were successful in recognition of unstable postures of a computer-animated body model and experienced egocentric motion. Successful recognition of unstable postures in these participants induces activation of distinct areas of the brain including bilateral parietal cortex, anterior cingulate cortex, and bilateral cerebellum. In addition, significant activation is observed in basal ganglia (caudate nucleus and putamen) but only during perception of animated postures. Our findings suggest the existence of modality-specific distributed activation of brain areas responsible for detection of postural instability.
Semyon Slobounov, Robert Simon, Richard Tutwiler and Matthew Rearick
The question regarding the invariant movement properties the central nervous system may organize to accomplish different motor task demands as reflected in EEG remains unsolved. Surprisingly, no systematic electrocortical research in humans has related movement preparation with different movement distance, although this area has been widely investigated in the field of motor control. This study examined whether the amplitude of discrete wrist movements influences the various EEG components both in time and frequency domains. Time-domain averaging techniques and Morlet wavelet transforms of EEG single trials were applied in order to extract three components [BP(0), Nl, and LPS] of movement related potentials (MRP) and to quantify changes in oscillatory activity of the movement-induced EEG waveforms accompanying 20, 40, and 60° unilateral wrist flexion movements. The experimental manipulations induced systematic changes in BP(0) and Nl amplitude along the midline (Fz, Cz, and Pz) with 20° movement showing the most negativity and 60° the least. The dominant energy within a 30-50 frequency cluster from bilateral precentral (C3, Cz, C4), frontal (F3, Fz, F4), and parietal (P3, Pz, P4) areas with maximum at vertex (Cz) also appeared to be sensitive to movement amplitude with the least power observed during 60° wrist flexion. This suggests that movement amplitude may be a controllable variable that is highly related with task-specific cortical activation primarily at frontocentral areas as reflected in EEG.
Semyon Slobounov, William Kraemer, Wayne Sebastianelli, Robert Simon and Shannon Poole
The primary purpose of this paper was to demonstrate how modem motion tracking technologies, i.e., the Hock of Birds, and computer visualization graphics may be used in a clinical setting. The idea that joint injury reduces proprioception was investigated, and data for injured subjects were compared to data for noninjured subjects (subjects in all experiments were college students). Two experiments showed that there were no significant losses in joint position sense in knee-injured subjects, and both injured and noninjured groups visually overestimated knee movements. However, injured subjects showed no significant differences when visual reproduction data were compared with actual movement data. In addition, these data indicated that injured subjects may have greater potential for apprehension than noninjured subjects, at least in terms of visual estimation of movement ranges. This is an idea that needs further testing.
Semyon M. Slobounov, Shannon T. Poole, Robert F. Simon, Elena S. Slobounov, Jill A. Bush, Wayne Sebastianelli and William Kraemer
Assessment and enhancement of joint position sense is an inexact science at best. Anew method of evaluating and improving this sense using motion-tracking technology that incorporates computer visualization graphics was examined. Injured and healthy subjects were evaluated for their abilities to determine shoulder joint position, after abduction, in two tasks. The first was active reproduction of a passively placed angle. The second was visual reproduction of such an angle. A training protocol was added to determine the effectiveness of proprioceptive training in conjunction with 3-D visualization techniques. The primary findings were (a) a significant difference (p = .05) in the level of joint position sense in injured vs. healthy subjects; (b) significantly less accurate reproduction of larger shoulder abduction vs. the smaller movement in the active reproduction task; (c) significantly greater ability to accurately reproduce angles actively vs. visually; and (d) that proprioception training using 3-D visualization techniques significantly increased active and visual reproductions of passively placed angles.
Semyon M. Slobounov, Robert Simon, Wayne Sebastianelli, Angela Carlson and William E. Buckley
A variety of assessment devices have been developed for scientific investigation on human movement that can also be used to assess the progress of a rehabilitation program. The present investigation was undertaken to show how this technology can be combined with the most aggressive type of medical intervention and rehabilitation. Advanced technology was used to assess the physical rehabilitation parameters of active range of motion (AROM) and sport-specific functional progression for an Olympic-caliber diver who had bilateral wrist problems. AROM was measured for both wrists using a Flock of Birds motion-tracking device, and functional progression was assessed with an Advanced Mechanical Technology Inc. force platform for measuring the center of pressure (CP) area. The results of the treatment were clinically favorable, with an increase in AROM and a decrease in the CP area for functional motor control. The technology provided useful information about the progress of a rehabilitation program.