@article{BohleRimpelSchauenburgetal.2019,
  author    = {Bohle, Hannah and Rimpel, J{\´e}r{\^o}me and Schauenburg, Gesche and Gebel, Arnd and Stelzel, Christine and Heinzel, Stephan and Rapp, Michael A. and Granacher, Urs},
  title     = {Behavioral and Neural Correlates of Cognitive-Motor Interference during Multitasking in Young and Old Adults},
  series = {Neural Plasticity},
  journal   = {Neural Plasticity},
  publisher = {Hindawi},
  address   = {New York},
  issn      = {2090-5904},
  doi       = {10.1155/2019/9478656},
  pages     = {20},
  year      = {2019},
  abstract  = {The concurrent performance of cognitive and postural tasks is particularly impaired in old adults and associated with an increased risk of falls. Biological aging of the cognitive and postural control system appears to be responsible for increased cognitive-motor interference effects. We examined neural and behavioral markers of motor-cognitive dual-task performance in young and old adults performing spatial one-back working memory single and dual tasks during semitandem stance. On the neural level, we used EEG to test for age-related modulations in the frequency domain related to cognitive-postural task load. Twenty-eight healthy young and 30 old adults participated in this study. The tasks included a postural single task, a cognitive-postural dual task, and a cognitive-postural triple task (cognitive dual-task with postural demands). Postural sway (i.e., total center of pressure displacements) was recorded in semistance position on an unstable surface that was placed on top of a force plate while performing cognitive tasks. Neural activation was recorded using a 64-channel mobile EEG system. EEG frequencies were attenuated by the baseline postural single-task condition and demarcated in nine Regions-of-Interest (ROIs), i.e., anterior, central, posterior, over the cortical midline, and both hemispheres. Our findings revealed impaired cognitive dual-task performance in old compared to young participants in the form of significantly lower cognitive performance in the triple-task condition. Furthermore, old adults compared with young adults showed significantly larger postural sway, especially in cognitive-postural task conditions. With respect to EEG frequencies, young compared to old participants showed significantly lower alpha-band activity in cognitive-cognitive-postural triple-task conditions compared with cognitive-postural dual tasks. In addition, with increasing task difficulty, we observed synchronized theta and delta frequencies, irrespective of age. Taskdependent alterations of the alpha frequency band were most pronounced over frontal and central ROIs, while alterations of the theta and delta frequency bands were found in frontal, central, and posterior ROIs. Theta and delta synchronization exhibited a decrease from anterior to posterior regions. For old adults, task difficulty was reflected by theta synchronization in the posterior ROI. For young adults, it was reflected by alpha desynchronization in bilateral anterior ROIs. In addition, we could not identify any effects of task difficulty and age on the beta frequency band. Our results shed light on age-related cognitive and postural declines and how they interact. Modulated alpha frequencies during high cognitive-postural task demands in young but not old adults might be reflective of a constrained neural adaptive potential in old adults. Future studies are needed to elucidate associations between the identified age-related performance decrements with task difficulty and changes in brain activity.},
  language  = {en}
}
@misc{BohleRimpelSchauenburgetal.2019,
  author    = {Bohle, Hannah and Rimpel, J{\´e}r{\^o}me and Schauenburg, Gesche and Gebel, Arnd and Stelzel, Christine and Heinzel, Stephan and Rapp, Michael A. and Granacher, Urs},
  title     = {Behavioral and Neural Correlates of Cognitive-Motor Interference during Multitasking in Young and Old Adults},
  series = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe},
  journal   = {Postprints der Universit{\"a}t Potsdam Humanwissenschaftliche Reihe},
  number    = {563},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-43597},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-435972},
  pages     = {20},
  year      = {2019},
  abstract  = {The concurrent performance of cognitive and postural tasks is particularly impaired in old adults and associated with an increased risk of falls. Biological aging of the cognitive and postural control system appears to be responsible for increased cognitive-motor interference effects. We examined neural and behavioral markers of motor-cognitive dual-task performance in young and old adults performing spatial one-back working memory single and dual tasks during semitandem stance. On the neural level, we used EEG to test for age-related modulations in the frequency domain related to cognitive-postural task load. Twenty-eight healthy young and 30 old adults participated in this study. The tasks included a postural single task, a cognitive-postural dual task, and a cognitive-postural triple task (cognitive dual-task with postural demands). Postural sway (i.e., total center of pressure displacements) was recorded in semistance position on an unstable surface that was placed on top of a force plate while performing cognitive tasks. Neural activation was recorded using a 64-channel mobile EEG system. EEG frequencies were attenuated by the baseline postural single-task condition and demarcated in nine Regions-of-Interest (ROIs), i.e., anterior, central, posterior, over the cortical midline, and both hemispheres. Our findings revealed impaired cognitive dual-task performance in old compared to young participants in the form of significantly lower cognitive performance in the triple-task condition. Furthermore, old adults compared with young adults showed significantly larger postural sway, especially in cognitive-postural task conditions. With respect to EEG frequencies, young compared to old participants showed significantly lower alpha-band activity in cognitive-cognitive-postural triple-task conditions compared with cognitive-postural dual tasks. In addition, with increasing task difficulty, we observed synchronized theta and delta frequencies, irrespective of age. Taskdependent alterations of the alpha frequency band were most pronounced over frontal and central ROIs, while alterations of the theta and delta frequency bands were found in frontal, central, and posterior ROIs. Theta and delta synchronization exhibited a decrease from anterior to posterior regions. For old adults, task difficulty was reflected by theta synchronization in the posterior ROI. For young adults, it was reflected by alpha desynchronization in bilateral anterior ROIs. In addition, we could not identify any effects of task difficulty and age on the beta frequency band. Our results shed light on age-related cognitive and postural declines and how they interact. Modulated alpha frequencies during high cognitive-postural task demands in young but not old adults might be reflective of a constrained neural adaptive potential in old adults. Future studies are needed to elucidate associations between the identified age-related performance decrements with task difficulty and changes in brain activity.},
  language  = {en}
}
@misc{BrahmsHeinzelRappetal.2022,
  author    = {Brahms, Markus and Heinzel, Stephan and Rapp, Michael A. and M{\"u}ckstein, Marie and Hortob{\´a}gyi, Tibor and Stelzel, Christine and Granacher, Urs},
  title     = {The acute effects of mental fatigue on balance performance in healthy young and older adults - A systematic review and meta-analysis},
  series = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  journal   = {Zweitver{\"o}ffentlichungen der Universit{\"a}t Potsdam : Humanwissenschaftliche Reihe},
  publisher = {Universit{\"a}tsverlag Potsdam},
  address   = {Potsdam},
  issn      = {1866-8364},
  doi       = {10.25932/publishup-56156},
  url       = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-561560},
  pages     = {1 -- 13},
  year      = {2022},
  abstract  = {Cognitive resources contribute to balance control. There is evidence that mental fatigue reduces cognitive resources and impairs balance performance, particularly in older adults and when balance tasks are complex, for example when trying to walk or stand while concurrently performing a secondary cognitive task. We conducted a systematic literature search in PubMed (MEDLINE), Web of Science and Google Scholar to identify eligible studies and performed a random effects meta-analysis to quantify the effects of experimentally induced mental fatigue on balance performance in healthy adults. Subgroup analyses were computed for age (healthy young vs. healthy older adults) and balance task complexity (balance tasks with high complexity vs. balance tasks with low complexity) to examine the moderating effects of these factors on fatigue-mediated balance performance. We identified 7 eligible studies with 9 study groups and 206 participants. Analysis revealed that performing a prolonged cognitive task had a small but significant effect (SMDwm = -0.38) on subsequent balance performance in healthy young and older adults. However, age- and task-related differences in balance responses to fatigue could not be confirmed statistically. Overall, aggregation of the available literature indicates that mental fatigue generally reduces balance in healthy adults. However, interactions between cognitive resource reduction, aging and balance task complexity remain elusive.},
  language  = {en}
}
@article{BrahmsHeinzelRappetal.2022,
  author    = {Brahms, Markus and Heinzel, Stephan and Rapp, Michael A. and M{\"u}ckstein, Marie and Hortob{\´a}gyi, Tibor and Stelzel, Christine and Granacher, Urs},
  title     = {The acute effects of mental fatigue on balance performance in healthy young and older adults - A systematic review and meta-analysis},
  series = {Acta Psychologica},
  volume    = {225},
  journal   = {Acta Psychologica},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1873-6297},
  doi       = {10.1016/j.actpsy.2022.103540},
  pages     = {1 -- 13},
  year      = {2022},
  abstract  = {Cognitive resources contribute to balance control. There is evidence that mental fatigue reduces cognitive resources and impairs balance performance, particularly in older adults and when balance tasks are complex, for example when trying to walk or stand while concurrently performing a secondary cognitive task. We conducted a systematic literature search in PubMed (MEDLINE), Web of Science and Google Scholar to identify eligible studies and performed a random effects meta-analysis to quantify the effects of experimentally induced mental fatigue on balance performance in healthy adults. Subgroup analyses were computed for age (healthy young vs. healthy older adults) and balance task complexity (balance tasks with high complexity vs. balance tasks with low complexity) to examine the moderating effects of these factors on fatigue-mediated balance performance. We identified 7 eligible studies with 9 study groups and 206 participants. Analysis revealed that performing a prolonged cognitive task had a small but significant effect (SMDwm = -0.38) on subsequent balance performance in healthy young and older adults. However, age- and task-related differences in balance responses to fatigue could not be confirmed statistically. Overall, aggregation of the available literature indicates that mental fatigue generally reduces balance in healthy adults. However, interactions between cognitive resource reduction, aging and balance task complexity remain elusive.},
  language  = {en}
}
@misc{ChaparroZechHeinzeletal.2017,
  author    = {Chaparro, Camilo G. A. Perez and Zech, Philipp A. and Heinzel, Stephan and Mayer, Frank and Wolfarth, Bernd and Rapp, Michael A. and Heissel, Andreas},
  title     = {Effects Of Aerobic \& Resistance Training On Cardiorespiratory Fitness In People Living with HIV. A Meta-analysis},
  series = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  volume    = {49},
  journal   = {Medicine and science in sports and exercise : official journal of the American College of Sports Medicine},
  publisher = {Lippincott Williams \& Wilkins},
  address   = {Philadelphia},
  issn      = {0195-9131},
  doi       = {10.1249/01.mss.0000519265.28705.86},
  pages     = {842 -- 842},
  year      = {2017},
  language  = {en}
}
@article{HeinenHeisselHeinzeletal.2023,
  author    = {Heinen, Darlene and Heissel, Andreas and Heinzel, Stephan and Fydrich, Thomas and Str{\"o}hle, Andreas and Rapp, Michael A. and Vogel, Heike},
  title     = {Effect of acute and long-term exercise on leptin levels in depressed outpatients},
  series = {BMC public health},
  volume    = {23},
  journal   = {BMC public health},
  publisher = {BioMed Central},
  address   = {London},
  issn      = {1471-2458},
  doi       = {10.1186/s12889-023-17362-4},
  pages     = {11},
  year      = {2023},
  abstract  = {Background Depression is a leading cause of disability worldwide and a significant contributor to the global burden of disease. Altered leptin levels are known to be associated with depressive symptoms, however discrepancies in the results of increased or decreased levels exist. Due to various limitations associated with commonly used antidepressant drugs, alternatives such as exercise therapy are gaining more importance. Therefore, the current study investigates whether depressed patients have higher leptin levels compared to healthy controls and if exercise is efficient to reduce these levels. Methods Leptin levels of 105 participants with major depressive disorder (MDD; 45.7\% female, age mean ± SEM: 39.1 ± 1.0) and 34 healthy controls (HC; 61.8\% female, age mean ± SEM: 36.0 ± 2.0) were measured before and after a bicycle ergometer test. Additionally, the MDD group was separated into three groups: two endurance exercise intervention groups (EX) differing in their intensities, and a waiting list control group (WL). Leptin levels were measured pre and post a 12-week exercise intervention or the waiting period. Results Baseline data showed no significant differences in leptin levels between the MDD and HC groups. As expected, correlation analyses displayed significant relations between leptin levels and body weight (HC: r = 0.474, p = 0.005; MDD: r = 0.198, p = 0.043) and even more with body fat content (HC: r = 0.755, p \< 0.001; MDD: r = 0.675, p \< 0.001). The acute effect of the bicycle ergometer test and the 12-week training intervention showed no significant changes in circulating leptin levels. Conclusion Leptin levels were not altered in patients with major depression compared to healthy controls and exercise, both the acute response and after 12 weeks of endurance training, had no effect on the change in leptin levels. Trial registration The study was registered at the German register for clinical studies (DRKS) and the International Clinical Trials Registry Platform of the World Health Organization https://trialsearch.who.int/Trial2.aspx?TrialID=DRKS00008869 on 28/07/2015.},
  language  = {en}
}
@article{HeinzelLawrenceKalliesetal.2015,
  author    = {Heinzel, Stephan and Lawrence, Jimmy B. and Kallies, Gunnar and Rapp, Michael A. and Heissel, Andreas},
  title     = {Using Exercise to Fight Depression in Older Adults},
  series = {GeroPsych : the journal of gerontopsychology and geriatric psychiatry},
  volume    = {28},
  journal   = {GeroPsych : the journal of gerontopsychology and geriatric psychiatry},
  publisher = {Hogrefe},
  address   = {Cambridge, Mass. ; G{\"o}ttingen [u.a.]},
  issn      = {1662-9647},
  doi       = {10.1024/1662-9647/a000133},
  pages     = {149 -- 162},
  year      = {2015},
  abstract  = {Depression is the most prevalent psychiatric disorder in the general population. Despite a large demand for efficient treatment options, the majority of older depressed adults does not receive adequate treatment: Additional low-threshold treatments are needed for this age group. Over the past two decades, a growing number of randomized controlled trials (RCT) have been conducted, testing the efficacy of physical exercise in the alleviation of depression in older adults. This meta-analysis systematically reviews and evaluates these studies; some subanalyses testing specific effects of different types of exercise and settings are also performed. In order to be included, exercise programs of the RCTs had to fulfill the criteria of exercise according to the American College of Sports Medicine, including a sample mean age of 60 or above and an increased level of depressive symptoms. Eighteen trials with 1,063 participants fulfilled our inclusion criteria. A comparison of the posttreatment depression scores between the exercise and control groups revealed a moderate effect size in favor of the exercise groups (standardized mean difference (SMD) of -0.68, p < .001). The effect was comparable to the results achieved when only the eleven trials with low risk of bias were included (SMD = -0.63, p < .001). The subanalyses showed significant effects for all types of exercise and for supervised interventions. The results of this meta-analysis suggest that physical exercise may serve as a feasible, additional intervention to fight depression in older adults. However, because of small sample sizes of the majority of individual trials and high statistical heterogeneity, results must be interpreted carefully.},
  language  = {en}
}
@article{HeinzelLorenzBrockhausetal.2014,
  author    = {Heinzel, Stephan and Lorenz, Robert C. and Brockhaus, Wolf-Ruediger and Wuestenberg, Torsten and Kathmann, Norbert and Heinz, Andreas and Rapp, Michael A.},
  title     = {Working memory load-dependent brain response predicts behavioral training gains in older adults},
  series = {The journal of neuroscience},
  volume    = {34},
  journal   = {The journal of neuroscience},
  number    = {4},
  publisher = {Society for Neuroscience},
  address   = {Washington},
  issn      = {0270-6474},
  doi       = {10.1523/JNEUROSCI.2463-13.2014},
  pages     = {1224 -- 1233},
  year      = {2014},
  abstract  = {In the domain of working memory (WM), a sigmoid-shaped relationship between WM load and brain activation patterns has been demonstrated in younger adults. It has been suggested that age-related alterations of this pattern are associated with changes in neural efficiency and capacity. At the same time, WM training studies have shown that some older adults are able to increase their WM performance through training. In this study, functional magnetic resonance imaging during an n-back WM task at different WM load levels was applied to compare blood oxygen level-dependent (BOLD) responses between younger and older participants and to predict gains in WM performance after a subsequent 12-session WM training procedure in older adults. We show that increased neural efficiency and capacity, as reflected by more "youth-like" brain response patterns in regions of interest of the frontoparietal WM network, were associated with better behavioral training outcome beyond the effects of age, sex, education, gray matter volume, and baseline WM performance. Furthermore, at low difficulty levels, decreases in BOLD response were found after WM training. Results indicate that both neural efficiency (i. e., decreased activation at comparable performance levels) and capacity (i. e., increasing activation with increasing WM load) of a WM-related network predict plasticity of the WM system, whereas WM training may specifically increase neural efficiency in older adults.},
  language  = {en}
}
@article{HeinzelLorenzPelzetal.2016,
  author    = {Heinzel, Stephan and Lorenz, Robert C. and Pelz, Patricia and Heinz, Andreas and Walter, Henrik and Kathmann, Norbert and Rapp, Michael A. and Stelzel, Christine},
  title     = {Neural correlates of training and transfer effects in working memory in older adults},
  series = {NeuroImage : a journal of brain function},
  volume    = {134},
  journal   = {NeuroImage : a journal of brain function},
  publisher = {Elsevier},
  address   = {San Diego},
  issn      = {1053-8119},
  doi       = {10.1016/j.neuroimage.2016.03.068},
  pages     = {236 -- 249},
  year      = {2016},
  abstract  = {As indicated by previous research, aging is associated with a decline in working memory (WM) functioning, related to alterations in fronto-parietal neural activations. At the same time, previous studies showed that WM training in older adults may improve the performance in the trained task (training effect), and more importantly, also in untrained WM tasks (transfer effects). However, neural correlates of these transfer effects that would improve understanding of its underlying mechanisms, have not been shown in older participants as yet. In this study, we investigated blood-oxygen-level-dependent (BOLD) signal changes during n-back performance and an untrained delayed recognition (Sternberg) task following 12 sessions (45 min each) of adaptive n-back training in older adults. The Sternberg task used in this study allowed to test for neural training effects independent of specific task affordances of the trained task and to separate maintenance from updating processes. Thirty-two healthy older participants (60-75 years) were assigned either to an n-back training or a no-contact control group. Before (t1) and after (t2) training/waiting period, both the n-back task and the Sternberg task were conducted while BOLD signal was measured using functional Magnetic Resonance Imaging (fMRI) in all participants. In addition, neuropsychological tests were performed outside the scanner. WM performance improved with training and behavioral transfer to tests measuring executive functions, processing speed, and fluid intelligence was found. In the training group, BOLD signal in the right lateral middle frontal gyrus/caudal superior frontal sulcus (Brodmann area, BA 6/8) decreased in both the trained n-back and the updating condition of the untrained Sternberg task at t2, compared to the control group. fMRI findings indicate a training-related increase in processing efficiency of WM networks, potentially related to the process of WM updating. Performance gains in untrained tasks suggest that transfer to other cognitive tasks remains possible in aging. (C) 2016 Elsevier Inc. All rights reserved.},
  language  = {en}
}
@article{HeinzelLorenzQuynhLamDuongetal.2017,
  author    = {Heinzel, Stephan and Lorenz, Robert C. and Quynh-Lam Duong, and Rapp, Michael A. and Deserno, Lorenz},
  title     = {Prefrontal-parietal effective connectivity during working memory in older adults},
  series = {Neurobiology of Aging},
  volume    = {57},
  journal   = {Neurobiology of Aging},
  publisher = {Elsevier},
  address   = {New York},
  issn      = {0197-4580},
  doi       = {10.1016/j.neurobiolaging.2017.05.005},
  pages     = {18 -- 27},
  year      = {2017},
  abstract  = {Theoretical models and preceding studies have described age-related alterations in neuronal activation of frontoparietal regions in a working memory (WM)load-dependent manner. However, to date, underlying neuronal mechanisms of these WM load-dependent activation changes in aging remain poorly understood. The aim of this study was to investigate these mechanisms in terms of effective connectivity by application of dynamic causal modeling with Bayesian Model Selection. Eighteen healthy younger (age: 20-32 years) and 32 older (60-75 years) participants performed an n-back task with 3 WM load levels during functional magnetic resonance imaging (fMRI). Behavioral and conventional fMRI results replicated age group by WM load interactions. Importantly, the analysis of effective connectivity derived from dynamic causal modeling, indicated an age-and performance-related reduction in WM load-dependent modulation of connectivity from dorsolateral prefrontal cortex to inferior parietal lobule. This finding provides evidence for the proposal that age-related WM decline manifests as deficient WM load-dependent modulation of neuronal top-down control and can integrate implications from theoretical models and previous studies of functional changes in the aging brain.},
  language  = {en}
}