12 results on '"Sven Passmann"'
Search Results
2. Applying time series analyses on continuous accelerometry data-A clinical example in older adults with and without cognitive impairment.
- Author
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Torsten Rackoll, Konrad Neumann, Sven Passmann, Ulrike Grittner, Nadine Külzow, Julia Ladenbauer, and Agnes Flöel
- Subjects
Medicine ,Science - Abstract
IntroductionMany clinical studies reporting accelerometry data use sum score measures such as percentage of time spent in moderate to vigorous activity which do not provide insight into differences in activity patterns over 24 hours, and thus do not adequately depict circadian activity patterns. Here, we present an improved functional data analysis approach to model activity patterns and circadian rhythms from accelerometer data. As a use case, we demonstrated its application in patients with mild cognitive impairment (MCI) and age-matched healthy older volunteers (HOV).MethodsData of two studies were pooled for this analysis. Following baseline cognitive assessment participants were provided with accelerometers for seven consecutive days. A function on scalar regression (FoSR) approach was used to analyze 24 hours accelerometer data.ResultsInformation on 48 HOV (mean age 65 SD 6 years) and 18 patients with MCI (mean age 70, SD 8 years) were available for this analysis. MCI patients displayed slightly lower activity in the morning hours (minimum relative activity at 6:05 am: -41.3%, 95% CI -64.7 to -2.5%, p = 0.031) and in the evening (minimum relative activity at 21:40 am: -48.4%, 95% CI -68.5 to 15.4%, p = 0.001) as compared to HOV after adjusting for age and sex.DiscussionUsing a novel approach of FoSR, we found timeframes with lower activity levels in MCI patients compared to HOV which were not evident if sum scores of amount of activity were used, possibly indicating that changes in circadian rhythmicity in neurodegenerative disease are detectable using easy-to-administer accelerometry.Clinical trialsEffects of Brain Stimulation During Nocturnal Sleep on Memory Consolidation in Patients With Mild Cognitive Impairments, ClinicalTrial.gov identifier: NCT01782391. Effects of Brain Stimulation During a Daytime Nap on Memory Consolidation in Patients With Mild Cognitive Impairment, ClinicalTrial.gov identifier: NCT01782365.
- Published
- 2021
- Full Text
- View/download PDF
3. The Modulation of Cognitive Performance with Transcranial Alternating Current Stimulation: A Systematic Review of Frequency-Specific Effects
- Author
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Katharina Klink, Sven Paßmann, Florian H. Kasten, and Jessica Peter
- Subjects
transcranial alternating current stimulation ,tACS ,cognitive performance ,systematic review ,Neurosciences. Biological psychiatry. Neuropsychiatry ,RC321-571 - Abstract
Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that allows the manipulation of intrinsic brain oscillations. Numerous studies have applied tACS in the laboratory to enhance cognitive performance. With this systematic review, we aim to provide an overview of frequency-specific tACS effects on a range of cognitive functions in healthy adults. This may help to transfer stimulation protocols to real-world applications. We conducted a systematic literature search on PubMed and Cochrane databases and considered tACS studies in healthy adults (age > 18 years) that focused on cognitive performance. The search yielded n = 109 studies, of which n = 57 met the inclusion criteria. The results indicate that theta-tACS was beneficial for several cognitive functions, including working memory, executive functions, and declarative memory. Gamma-tACS enhanced performance in both auditory and visual perception but it did not change performance in tasks of executive functions. For attention, the results were less consistent but point to an improvement in performance with alpha- or gamma-tACS. We discuss these findings and point to important considerations that would precede a transfer to real-world applications.
- Published
- 2020
- Full Text
- View/download PDF
4. Effects of Different Analysis Strategies on Paired Associative Stimulation. A Pooled Data Analysis from Three Research Labs.
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Jacob Lahr, Sven Paßmann, Jonathan List, Werner Vach, Agnes Flöel, and Stefan Klöppel
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Medicine ,Science - Abstract
Paired associative stimulation (PAS) is a widely used transcranial magnetic stimulation (TMS) paradigm to non-invasively induce synaptic plasticity in the human brain in vivo. Altered PAS-induced plasticity has been demonstrated for several diseases. However, researchers are faced with a high inter- and intra-subject variability of the PAS response. Here, we pooled original data from nine PAS studies from three centers and analyzed the combined dataset of 190 healthy subjects with regard to age dependency, the role of stimulation parameters and the effect of different statistical methods. We observed no main effect of the PAS intervention over all studies (F(2;362) = 0.44; p = 0.644). The rate of subjects showing the expected increase of motor evoked potential (MEP) amplitudes was 53%. The PAS effect differed significantly between studies as shown by a significant interaction effect (F(16;362) = 1.77; p = 0.034) but post-hoc testing did not reveal significant effects after correction for multiple tests. There was a trend toward increased variability of the PAS effect in older subjects. Acquisition parameters differed across studies but without systematically influencing changes in MEP-size. The use of post/baseline quotients systematically indicated stronger PAS effects than post/baseline difference or the logarithm of the post/baseline quotient. The non-significant PAS effects across studies and a wide range of responder rates between studies indicate a high variability of this method. We were thus not able to replicate findings from a previous meta-analysis showing robust effects of PAS. No pattern emerged regarding acquisition parameters that at this point could guide future studies to reduce variability and help increase response rate. For future studies, we propose to report the responder rate and recommend the use of the logarithmized post/baseline quotient for further analyses to better address the possibility that results are driven by few extreme cases.
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- 2016
- Full Text
- View/download PDF
5. Brain stimulation during an afternoon nap boosts slow oscillatory activity and memory consolidation in older adults.
- Author
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Julia Ladenbauer, Nadine Külzow, Sven Passmann, Daria Antonenko, Ulrike Grittner, Sascha Tamm, and Agnes Flöel
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- 2016
- Full Text
- View/download PDF
6. Applying time series analyses on continuous accelerometry data—A clinical example in older adults with and without cognitive impairment
- Author
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Julia Ladenbauer, Agnes Flöel, Sven Passmann, Ulrike Grittner, Torsten Rackoll, Konrad Neumann, and Nadine Külzow
- Subjects
Male ,epidemiology [Cognitive Dysfunction] ,Physiology ,Social Sciences ,Audiology ,Alzheimer's Disease ,Diagnostic Radiology ,Electronics Engineering ,Medical Conditions ,Accelerometry ,Medicine and Health Sciences ,Psychology ,Morning ,Cognitive Impairment ,Cognitive Neurology ,Radiology and Imaging ,Age Factors ,Cognition ,Neurodegenerative Diseases ,Middle Aged ,Magnetic Resonance Imaging ,Circadian Rhythm ,Circadian Rhythms ,Neurology ,Medicine ,Engineering and Technology ,Memory consolidation ,Female ,600 Technik, Medizin, angewandte Wissenschaften::610 Medizin und Gesundheit::610 Medizin und Gesundheit ,Research Article ,medicine.medical_specialty ,Evening ,Imaging Techniques ,Science ,Cognitive Neuroscience ,methods [Accelerometry] ,Research and Analysis Methods ,Neuropsychology ,Diagnostic Medicine ,Mental Health and Psychiatry ,medicine ,Humans ,Cognitive Dysfunction ,ddc:610 ,Circadian rhythm ,Neuropsychological Testing ,Aged ,Memory Consolidation ,business.industry ,Chronotype ,Biology and Life Sciences ,Nap ,diagnosis [Cognitive Dysfunction] ,Brain stimulation ,Cognitive Science ,Dementia ,Electronics ,Accelerometers ,business ,Physiological Processes ,Sleep ,Chronobiology ,Neuroscience - Abstract
IntroductionCurrent analysis approaches of accelerometry data use sum score measures which do not provide insight in activity patterns over 24 hours, and thus do not adequately depict circadian activity patterns. Here, we used a functional approach to analyze accelerometer data that models activity pattern and circadian rhythm. As a test case, we demonstrated its application in patients with mild cognitive impairment (MCI) and age-matched healthy older volunteers (HOV). Moreover, we assessed the impact of chronotype on distribution of activity data.MethodsData of two studies were pooled for this analysis. Following baseline cognitive assessment participants were provided with accelerometers for seven consecutive days. A function on scalar regression (FoSR) approach was used to analyze 24 hours accelerometer data. In a second step, analyses were controlled for chronotype using the German version of the morningness-eveningness questionnaire (d-MEQ).ResultsInformation on 47 HOV (mean age 66 SD 6 years) and 13 patients with MCI (mean age 69, SD 8 years) were available for this analysis. MCI patients displayed slightly higher activity in the morning hours as compared to HOV (maximum relative activity at 7:35 am: 75.6%, 95% CI 2.6 to 200.4%, p = 0.031). After controlling for d-MEQ, disturbed activity patterns were found in MCI of intermediate or evening chronotype, compared to HOV, i.e., MCI presented with higher activities in the morning hours (peak at 8:40 am: 357.6%, 95% CI 92.9 to 985.1, p < 0.001) and early afternoon hours (peak at 1:40 pm: 401.8%, 95% CI 63.9 to 1436.4, p < 0.001).DiscussionUsing a novel approach of FoSR, we found timeframes with higher activity levels in MCI patients compared to HOV which were not evident if sum scores of amount of activity were used. In addition, we found that previously described activity patterns as a function of chronotype swere altered in MCI patients, possibly indicating that changes in circadian rhythmicity in neurodegenerative disease are detectable using easy-to-administer accelerometry.Clinical TrialsEffects of Brain Stimulation During Nocturnal Sleep on Memory Consolidation in Patients With Mild Cognitive Impairments, https://clinicaltrials.gov/ct2/show/NCT01782391?term=NCT01782391&rank=1,ClinicalTrial.gov identifier: NCT01782391Effects of Brain Stimulation During a Daytime Nap on Memory Consolidation in Patients With Mild Cognitive Impairment,https://clinicaltrials.gov/ct2/show/NCT01782365?term=NCT01782365&rank=1,ClinicalTrial.gov identifier: NCT01782365
- Published
- 2021
7. The Modulation of Cognitive Performance with Transcranial Alternating Current Stimulation: A Systematic Review of Frequency-Specific Effects
- Author
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Sven Paßmann, Florian H. Kasten, Jessica Peter, and Katharina Klink
- Subjects
tACS ,medicine.medical_specialty ,transcranial alternating current stimulation ,Visual perception ,Working memory ,General Neuroscience ,Stimulation ,Cognition ,Review ,Audiology ,Executive functions ,lcsh:RC321-571 ,stomatognathic diseases ,systematic review ,Brain stimulation ,medicine ,Effects of sleep deprivation on cognitive performance ,150 Psychology ,Psychology ,cognitive performance ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,Transcranial alternating current stimulation - Abstract
Transcranial alternating current stimulation (tACS) is a non-invasive brain stimulation technique that allows the manipulation of intrinsic brain oscillations. Numerous studies have applied tACS in the laboratory to enhance cognitive performance. With this systematic review, we aim to provide an overview of frequency-specific tACS effects on a range of cognitive functions in healthy adults. This may help to transfer stimulation protocols to real-world applications. We conducted a systematic literature search on PubMed and Cochrane databases and considered tACS studies in healthy adults (age > 18 years) that focused on cognitive performance. The search yielded n = 109 studies, of which n = 57 met the inclusion criteria. The results indicate that theta-tACS was beneficial for several cognitive functions, including working memory, executive functions, and declarative memory. Gamma-tACS enhanced performance in both auditory and visual perception but it did not change performance in tasks of executive functions. For attention, the results were less consistent but point to an improvement in performance with alpha- or gamma-tACS. We discuss these findings and point to important considerations that would precede a transfer to real-world applications. Keywords: cognitive performance; systematic review; tACS; transcranial alternating current stimulation.
- Published
- 2020
8. Boosting Slow Oscillatory Activity Using tDCS during Early Nocturnal Slow Wave Sleep Does Not Improve Memory Consolidation in Healthy Older Adults
- Author
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Daria Antonenko, Sascha Tamm, Nadine Külzow, Agnes Flöel, Ulrike Grittner, Sven Paßmann, and Julia Ladenbauer
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Male ,medicine.medical_specialty ,Biophysics ,Stimulation ,Visuo-spatial task ,Audiology ,Transcranial Direct Current Stimulation ,Non-rapid eye movement sleep ,Hippocampus ,050105 experimental psychology ,Procedural memory ,Developmental psychology ,lcsh:RC321-571 ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Declarative memory ,Humans ,0501 psychology and cognitive sciences ,Single-Blind Method ,lcsh:Neurosciences. Biological psychiatry. Neuropsychiatry ,Slow-wave sleep ,Aged ,Memory Consolidation ,Aged, 80 and over ,Sleep Stages ,Cross-Over Studies ,General Neuroscience ,05 social sciences ,Repeated measures design ,Transcranial slow oscillating stimulation ,Middle Aged ,Crossover study ,Healthy Volunteers ,Frontal Lobe ,Treatment Outcome ,Older subjects ,Memory consolidation ,Female ,Neurology (clinical) ,Psychology ,Sleep ,030217 neurology & neurosurgery ,Consolidation - Abstract
Background Previous studies have demonstrated an enhancement of hippocampal-dependent declarative memory consolidation, associated slow wave sleep (SWS) and slow wave activity (SWA) after weak slow oscillatory stimulation (so-tDCS) during early non-rapid eye movement sleep (NREM) in young adults. Recent studies in older individuals could not confirm these findings. However, it remained unclear if this difference was due to variations in study protocol or to the age group under study. Objective/Hypothesis Here, we asked if so-tDCS promotes neurophysiological events and associated sleep-dependent memory in the visuo-spatial domain in older adults, using a stimulation protocol that closely resembled the one employed in young adults. Methods In a randomized, placebo-controlled single-blind (participant) crossover study so-tDCS (0.75 Hz; max. current density 0.522 mA/cm 2 ) vs. sham stimulation was applied over the frontal cortex of 21 healthy older subjects. Impact of stimulation on frequency band activity (linear mixed models), two declarative and one procedural memory tasks (repeated measures ANOVA) and percentage of sleep stages (comparison of means) was assessed. Results so-tDCS, as compared to sham, increased SWA and spindle activity immediately following stimulation, accompanied by significantly impaired visuo-spatial memory consolidation. Furthermore, verbal and procedural memory remained unchanged, while percentage of NREM sleep stage 4 was decreased over the entire night (uncorrected). Conclusion so-tDCS increased SWA and spindle activity in older adults, events previously associated with stimulation-induced improved consolidation of declarative memories in young subjects. However, consolidation of visuo-spatial (primary outcome) and verbal memories was not beneficially modulated, possibly due to decline in SWS over the entire night that may have prevented and even reversed immediate beneficial effects of so-tDCS on SWA.
- Published
- 2016
9. P34 Disrupted activity patterns in evening and morning chronotypes between mild cognitive impaired patients and older, non-impaired controls
- Author
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Agnes Flöel, Julia Ladenbauer, Ulrike Grittner, Sven Passmann, Torsten Rackoll, Nadine Külzow, and Konrad Neumann
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medicine.medical_specialty ,Evening ,Neurology ,business.industry ,Physiology (medical) ,Medicine ,Chronotype ,Cognition ,Neurology (clinical) ,Audiology ,business ,Sensory Systems ,Morning - Published
- 2019
10. Brain stimulation during an afternoon nap boosts slow oscillatory activity and memory consolidation in older adults
- Author
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Agnes Flöel, Sascha Tamm, Sven Passmann, Daria Antonenko, Nadine Külzow, Ulrike Grittner, and Julia Ladenbauer
- Subjects
Male ,Aging ,Brain activity and meditation ,Cognitive Neuroscience ,Sleep spindle ,Stimulation ,Transcranial Direct Current Stimulation ,050105 experimental psychology ,03 medical and health sciences ,0302 clinical medicine ,Humans ,0501 psychology and cognitive sciences ,Cognitive decline ,Aged ,Memory Consolidation ,05 social sciences ,Middle Aged ,Brain Waves ,Nap ,Neurology ,Brain stimulation ,Mental Recall ,Memory consolidation ,Female ,Verbal memory ,Psychology ,Sleep ,Neuroscience ,030217 neurology & neurosurgery - Abstract
Sleep-related consolidation of declarative memories, as well as associated neurophysiological events such as slow oscillatory and spindle activity, deteriorate in the course of aging. This process is accelerated in neurodegenerative disease. Transcranial slow oscillatory stimulation (so-tDCS) during sleep has been shown to enhance slow oscillatory brain activity and thereby improve memory consolidation in young subjects. Here, we investigated whether so-tDCS applied to older adults during an afternoon nap exerts similar effects. Eighteen older human subjects were assessed using visuo-spatial (picture memory, primary, and location memory) and verbal memory tasks before and after a 90-min nap either comprising weak so-tDCS at 0.75Hz over fronto-central location or sham (no) stimulation in a within-subject design. Electroencephalographic activity was recorded throughout the naps and immediate effects of stimulation on brain activity were evaluated. Here, spectral power within three frequency bands of interest were computed, i.e., slow oscillatory activity, slow spindle and fast spindle activity; in 1-min stimulation-free intervals following 5 stimulation blocks. So-tDCS significantly increased frontal slow oscillatory activity as well as fast spindle activity, and significantly improved picture memory retention after sleep. Retention in the location memory subtask and in the verbal memory task was not affected. These findings may indicate a novel strategy to counteract cognitive decline in aging in a convenient manner during brief daytime naps.
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- 2016
11. Electrodermal lability as an indicator for subjective sleepiness during total sleep deprivation
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Lars Michael, Sven Passmann, and Ruth Becker
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medicine.medical_specialty ,Visual analogue scale ,Lability ,Cognitive Neuroscience ,Repeated measures design ,General Medicine ,Audiology ,Total sleep deprivation ,Behavioral Neuroscience ,Sleep deprivation ,Go/no go ,medicine ,Circadian rhythm ,medicine.symptom ,Psychiatry ,Skin conductance ,Psychology - Abstract
Summary The present study addresses the suitability of electrodermal lability as an indicator of individual vulnerability to the effects of total sleep deprivation. During two complete circadian cycles, the effects of 48 h of total sleep deprivation on physiological measures (electrodermal activity and body temperature), subjective sleepiness (measured by visual analogue scale and tiredness symptom scale) and task performance (reaction time and errors in a go/no go task) were investigated. Analyses of variance with repeated measures revealed substantial decreases of the number of skin conductance responses, body temperature, and increases for subjective sleepiness, reaction time and error rates. For all changes, strong circadian oscillations could be observed as well. The electrodermal more labile subgroup reported higher subjective sleepiness compared with electrodermal more stable participants, but showed no differences in the time courses of body temperature and task performance. Therefore, electrodermal lability seems to be a specific indicator for the changes in subjective sleepiness due to total sleep deprivation and circadian oscillations, but not a suitable indicator for vulnerability to the effects of sleep deprivation per se.
- Published
- 2011
12. P1‐024: Improved memory consolidation by slow oscillatory brain stimulation during an afternoon nap in older adults
- Author
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Sascha Tamm, Julia Schneider, Daria Antonenko, Sven Passmann, Nadine Külzow, and Agnes Flöel
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Epidemiology ,business.industry ,Health Policy ,Developmental psychology ,Nap ,Psychiatry and Mental health ,Cellular and Molecular Neuroscience ,Developmental Neuroscience ,Brain stimulation ,Medicine ,Memory consolidation ,Neurology (clinical) ,Geriatrics and Gerontology ,business ,Neuroscience - Published
- 2015
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