Vera Abeln

Exercise, mood and cognitive performance in intellectual disability—A neurophysiological approach

While numerous researches addressed the connection between physical exercise, changes in brain cortical activity and its relationship to psycho-physiological processes, most of these neuro-scientific studies were set up for healthy individuals. However, the benefits of exercise, such as well being, physical and cognitive health enhancements are also becoming increasingly important for intellectually disabled individuals. This study aimed to localize electroencephalographic activity changes in intellectually disabled individuals following a moderate running exercise for 30 min. An increase in cognitive performance and in mood was hypothesized to correlate with a decrease in fronto-temporal brain areas following exercise. Significant changes in cortical current density in frontal brain areas as well as decreases in perceived physical energy could be shown. Overall motivational states (including self-confidence and social acceptance) as well as positive mood increased significantly. However, no changes could be observed for the cognitive tasks following exercise. With respect to the data provided here there is reason to believe, that a self-selected pace running exercise, enhances self-esteem, coincided with cortical activity changes in fronto-temporal brain areas.

The influence of exercise on prefrontal cortex activity and cognitive performance during a simulated space flight to Mars (MARS500).

With respect to the plans of national and internationals space agencies to send people to Mars or Moon, long-term isolation studies are performed to learn about the psycho-physiological and psycho-social limitations of such missions. From June 3rd 2010 to November 4th 2011 six participants lived under totally isolated and confined conditions in the MARS500 habitat located in Moscow. Despite the possibility to mimic the condition of space travel, this study allowed for experimental conditions under very reliable and traceable conditions. As exercise is widely discussed to have a positive impact on neuro-cognitive performance, this study aimed to test the effect of different exercise protocol (endurance/strength orientated) on brain cortical activity and cognitive performance. Brain cortical activity was recorded using a 16 channel EEG before and after exercise across the 520 days of confinement. Cognitive performance was assessed using three commercially available brain games. Following the theory of transient hypofrontality, results show a significant decrease of frontal brain cortical activity after exercise (p<.05) which was most expressed after endurance orientated protocols. Cognitive performance was improved following running sessions on an active treadmill (p<.05). Results let us assume that not exercise per se acts as a neuro-enhancer. It is more likely that a general defocusing caused by an immersion into exercise is necessary to improve cognitive performance.

Artificial gravity exposure impairs exercise-related neurophysiological benefits

Artificial gravity (AG) exposure is suggested to counteract health deconditioning, theoretically complementing exercise during space habitations. Exercise-benefits on mental health are well documented (i.e. well-being, enhanced executive functions). Although AG is coherent for the integrity of fundamental physiological systems, the effects of its exposure on neurophysiological processes related to cognitive performance are poorly understood and therefore characterize the primary aim of this study. 16 healthy males participated in two randomly assigned sessions, AG and exercise (30minute each). Participants were exposed to AG at continuous +2Gz in a short-arm human centrifuge and performed moderate exercise (cycling ergometer). Using 64 active electrodes, resting EEG was recorded before (pre), immediately after (post), and 15min after (post15) each session. Alpha (7.5-12.5Hz) and beta frequencies (12.5-35.0Hz) were exported for analysis. Cognitive performance and mood states were assessed before and after each session. Cognitive performance improved after exercise (p<0.05), but not after AG. This was reflected by typical EEG patterns after exercise, however not after AG. Frontal alpha (post p<0.01, post15 p<0.001) and beta activity (post15 p<0.001) increased after AG compared to a decrease in frontal alpha (post15 p<0.05) and beta activity (post p<0.01) after exercise. Relaxed cortical states were indicated after exercise, but were less apparent after AG. Changes in mood states failed significance after both sessions. Summarized, the benefits to mental health, recorded after exercise, were absent after AG, indicating that AG might cause neurocognitive deconditioning.

The impact of long-term confinement and exercise on central and peripheral stress markers

Long-term isolation has been reported to have impact on psycho-physiological performance in humans. As part of the 520 days isolation study (MARS500, n=6) from June 3rd 2010 to November 4th 2011, this study aimed to show that stress caused by isolation and confinement is mirrored in cortical activity and cortisol levels and that exercise is a valid countermeasure. Cortical activity was measured by electroencephalography (EEG) pre- and post-moderate exercise every two weeks, salivary cortisol was taken every 60 days. Data show a decrease of global cortical activity, in both alpha- and beta-activity (p<.05-p<.001), and an increase of salivary cortisol (p<.05-p<.001), during the isolation, indicating that isolation acts as a chronic stressor with impact on cortical activity and cortisol levels. Moderate exercise leads to an increase (p<.01) in cortical activity. Therefore, during long-term space missions the factor isolation must be kept in mind as the reduction of cortical activity and the heightened stress level could impair performance. However moderate exercise might be able to counteract this impairment.

Brainwave entrainment for better sleep and post-sleep state of young elite soccer players – A pilot study

Abstract The effect of sleep deprivation on psychophysical performance and well-being is comprehensively investigated. Research investigating the effect of improved sleep is rare. Just as little exists about attempts to support athletic mental state and performance by improving sleep quality. This study aims to investigate whether sleep quality of top athletes can be improved by auditory brainwave entrainment and whether this leads to enhancements of post-sleep psychophysical states. In a pilot study, 15 young elite soccer players were stimulated for eight weeks during sleep with binaural beats around 2–8 Hz. Once a week after wake-up, participants completed three different questionnaires: a sleep diary, an adjective list for psychophysical and motivational state, and a self-assessment questionnaire for sleep and awakening quality. Fifteen sport students executed the same protocol sleeping on the same pillow, but without stimulation. Subjective ratings of sleep and awakening quality, sleepiness and motivational state were significantly improved only in the intervention group, but did not impact their perceived physical state. In summary, eight weeks of auditory stimulation with binaural beats improved perceived sleep quality and the post-sleep state of athletes, whereas the effect on physical level is assumed to occur in a time-delayed fashion. It seems to be worthwhile – to further elaborate long-time effects and consequences on physical and mental performance.

The impact of chronic stress burden of 520-d isolation and confinement on the physiological response to subsequent acute stress challenge

Collective evidence indicates that previous exposure to stressful condition might be able to induce changes in brain structure, HPA axis activity and related neurotransmission, and accordingly affect physiological responses to subsequent challenges. During long-term spaceflight, space travelers have to live under the condition of isolation and confinement in the spacecraft for a long period. It is still largely unknown if this kind of chronic stress burden can induce any long-lasting changes. To address this question, following 520-d isolation and confinement simulating a flight to Mars, the participants and a matched control group were exposed to an acute stress challenge called parabolic flight. Brain cortical activity, HPA axis activity, and sympathetic adrenal-medullary system response were monitored by EEG signal, cortisol secretion, and catecholamine production, respectively. We observed enhanced EEG signals, elevated cortisol levels and increased adrenaline productions. A group effect on cortisol output was revealed showing higher cortisol peak levels in the Mars520 group as compared to the control group, suggesting that HPA axis was to a certain extent more activated in the subjects who had chronic stress experience.

Exercise in Isolation- A Countermeasure for Electrocortical, Mental and Cognitive Impairments

Introduction Mental impairments, including deterioration of mood and cognitive performance, are known to occur during isolation and space missions, but have been insufficiently investigated. Appropriate countermeasures are required, such as exercise, which is known to prevent mood disorders for prolonged space and isolation missions. Based on the interaction of brain activity, mood and cognitive performance, this study aims to investigate the effect of long-term isolation and confinement and the long-term effect of exercise on these parameters. Methods Eight male volunteers were isolated and confined for about eight month during the winter period at the Antarctic Concordia Station. Every six weeks electroencephalographic measurements were recorded under rest conditions, and cognitive tests and a mood questionnaire were executed. Based individual training logs, subjects were afterwards separated into an active (> 2500 arbitrary training units/interval) or inactive (< 2500 arbitrary training units/interval) group. Results A long-term effect of exercise was observed for brain activity and mood. Regularly active people showed a decreased brain activity (alpha and beta) in the course of isolation, and steady mood. Inactive people instead first increased and than remained at high brain activity accompanied with a deterioration of mood. No effect of exercise and isolation was found for cognitive performance. Conclusion The findings point out the positive effect of regularly performed voluntary exercise, supporting subjective mental well-being of long-term isolated people. The choice to be regularly active seems to support mental health, which is not only of interest for future isolation and space missions.

EEG coherence during mental rotation of letters, hands and scenes

The purpose of the present study was to investigate differences in the electrocortical synchronization pattern during mental rotation of three different object categories as well as six different rotation angles. Therefore, event-related coherence of the electroencephalographic (EEG) activity between selective frontal and parietal electrode pairs of ten subjects was measured during the performance of a mental rotation task consisting of rotation of letters, hands and scenes. Statistical analysis showed an increased coherence of frontal and parietal electrode pairs for the condition LETTER in comparison to the other conditions in the alpha1- (8.5-10 Hz) and alpha2-band (10, 5-12 Hz) supporting the notion of different mental rotation mechanisms for externally and internally represented objects. Additionally decreased coherence of the frontal and parietal electrode pairs was found for the rotation angles 30° to 150° in comparison to the 0° and 180° rotations for the alpha1- and alpha2-band as well as the gamma frequency band (30-45 Hz). It is assumed that this decrease of synchronization reflects the mental rotation process implying that the mental rotation process of 180° differs from the rotation process of all other rotation angles.

Brain-imaging during an isometric leg extension task at graded intensities

Imaging the brain during complex and intensive movements is challenging due to the susceptibility of brain-imaging methods for motion and myogenic artifacts. A few studies measured brain activity during either single-joint or low-intensity exercises; however, the cortical activation state during larger movements with increases up to maximal intensity has barely been investigated so far. Eleven right-handed volunteers (22–45 years in age) performed isometric leg extensions with their right leg at 20, 40, 60, 80, and 100% of their maximal voluntary contraction. Contractions were hold for 20 s respectively. Electroencephalographic (EEG) and electromyographic (EMG) activity was recorded. Standardized low-resolution brain electromagnetic tomography (sLORETA) was used to localize the cortical current density within the premotor (PMC), primary motor (M1), primary somatosensory (S1) and somatosensory association cortex (SAC). ANOVA was used for repeated measures for comparison of intensities and between the left and right hemispheres. The quality of the EEG signal was satisfying up to 80% intensity. At 100% half of the participants were not able to keep their neck and face muscles relaxed, leading to myogenic artifacts. Higher contralateral vs. ipsilateral hemispheric activity was found for the S1, SAC and, PMC. M1 possessed higher ipsilateral activity. The highest activity was localized in the M1, followed by S1, PMC, and SAC. EMG activity and cortical current density within the M1 increased with exercise intensity. EEG recordings during bigger movements up to submaximal intensity (80%) are possible, but maximal intensities are still hard to investigate when subjects contracted their neck and face muscles at the same time. Isometric contractions mainly involve the M1, whereas the S1, PMC, and SAC seem not to be involved in the force output. Limitations and recommendations for future studies are discussed.

Cognitive Impairment Is Reflected by an Increased Difference between Real and Imagined Timed Up and Go Test Performance

Background: Recent research suggests using an imaginary version of the Timed Up and Go test (TUG) for a first assessment of cognitive impairment. By using the time difference between a real (TUGr) and an imagined (TUGi) TUG task, the objective of this study was to examine the effect of cognitive impairment on motor imagery ability. Methods: Fifty-two participants (mean age 69.3 ± 4.0 years) with mild cognitive impairment or subjective cognitive impairment were included in this study. The time difference between the TUGr and the TUGi was used as the main outcome. The Trail Making Test part B (TMT B), the ratio between TMT A and TMT B, and the Montreal Cognitive Assessment (MoCA) battery were the main independent variables. Results: The difference between TUGr and TUGi performance time and the TMT B performance time increased with decreasing cognitive function (p < 0.01). There was no relationship between TUGr and TUGi performance time and TMT B/A ratio. There were significant correlations between TUG time differences and the MoCA score (r = -0.489, p < 0.01), the TMT B (r = 0.364, p < 0.01), and the TMT B/A ratio (r = 0.377, p < 0.01). Conclusion: The combination of TUGr and TUGi may have added value in assessing cognitive impairment, which is a possible pre-stage of dementia.