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Pun M, Guadagni V, Longman RS, Hanly PJ, Hill MD, Anderson TJ, Hogan DB, Rawling JM, Poulin M. Sex differences in the association of sleep spindle density and cognitive performance among community-dwelling middle-aged and older adults with obstructive sleep apnea. J Sleep Res 2024; 33:e14095. [PMID: 37963455 DOI: 10.1111/jsr.14095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 10/24/2023] [Accepted: 10/26/2023] [Indexed: 11/16/2023]
Abstract
Recent studies have found associations between obstructive sleep apnea and cognitive decline. The underlying mechanisms are still unclear. Here, we investigate the associations between changes in micro-architecture, specifically sleep spindles, and cognitive function in community-dwelling middle-aged and older adults, some with obstructive sleep apnea, with a focus on sex differences. A total of 125 voluntary participants (mean age 66.0 ± 6.4 years, 64 females) from a larger cohort (participants of the Brain in Motion Studies I and II) underwent 1 night of in-home polysomnography and a neuropsychological battery (sleep and cognitive testing were conducted within 2 weeks of each other). A semi-automatic computerized algorithm was used to score polysomnography data and detect spindle characteristics in non-rapid eye movement Stages 2 and 3 in both frontal and central electrodes. Based on their apnea-hypopnea index, participants were divided into those with no obstructive sleep apnea (apnea-hypopnea index < 5 per hr, n = 21), mild obstructive sleep apnea (5 ≥ apnea-hypopnea index < 15, n = 47), moderate obstructive sleep apnea (15 ≥ apnea-hypopnea index < 30, n = 34) and severe obstructive sleep apnea (apnea-hypopnea index ≥ 30, n = 23). There were no significant differences in spindle characteristics between the four obstructive sleep apnea severity groups. Spindle density and percentage of fast spindles were positively associated with some verbal fluency measures on the cognitive testing. Sex might be linked with these associations. Biological sex could play a role in the associations between spindle characteristics and some verbal fluency measures. Obstructive sleep apnea severity was not found to be a contributing factor in this non-clinical community-dwelling cohort.
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Affiliation(s)
- Matiram Pun
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Veronica Guadagni
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- O'Brien Institute for Public Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Richard Stewart Longman
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Psychology Service, Foothills Medical Centre, Alberta Health Service, Calgary, Alberta, Canada
| | - Patrick J Hanly
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Sleep Centre, Foothills Medical Centre, Calgary, Alberta, Canada
| | - Michael D Hill
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- O'Brien Institute for Public Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Todd J Anderson
- Department of Cardiac Science, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - David B Hogan
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- O'Brien Institute for Public Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jean M Rawling
- Department of Family Medicine, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Marc Poulin
- Department of Physiology & Pharmacology, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Department of Clinical Neurosciences, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- O'Brien Institute for Public Health, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Libin Cardiovascular Institute of Alberta, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- Faculty of Kinesiology, University of Calgary, Calgary, Alberta, Canada
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Wang Q, Stone KL, Lu Z, Tian S, Zheng Y, Zhao B, Bao Y, Shi L, Lu L. Associations between Longitudinal Changes in Sleep Stages and Risk of Cognitive Decline in Older Men. Sleep 2024:zsae125. [PMID: 38829819 DOI: 10.1093/sleep/zsae125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Indexed: 06/05/2024] Open
Abstract
STUDY OBJECTIVES To investigate the relationships between longitudinal changes in sleep stages and the risk of cognitive decline in older men. METHODS This study included 978 community-dwelling older men who participated in the first (2003-2005) and second (2009-2012) sleep ancillary study visits of the Osteoporotic Fractures in Men Study. We examined the longitudinal changes in sleep stages at the initial and follow-up visits, and the association with concurrent clinically relevant cognitive decline during the 6.5-year follow-up. RESULTS Men with low to moderate (quartile 2, Q2) and moderate increase (Q3) in N1 sleep percentage had a reduced risk of cognitive decline on the Modified Mini-Mental State Examination compared to those with a substantial increase (Q4) in N1 sleep percentage. Additionally, men who experienced a low to moderate (Q2) increase in N1 sleep percentage had a lower risk of cognitive decline on the Trails B compared with men in the reference group (Q4). Furthermore, men with the most pronounced reduction (Q1) in N2 sleep percentage had a significantly higher risk of cognitive decline on the Trails B compared to those in the reference group (Q4). No significant association was found between changes in N3 and rapid eye movement sleep and the risk of cognitive decline. CONCLUSIONS Our results suggested that a relatively lower increase in N1 sleep showed a reduced risk of cognitive decline. However, a pronounced decrease in N2 sleep was associated with concurrent cognitive decline. These findings may help identify older men at risk of clinically relevant cognitive decline.
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Affiliation(s)
- Qianwen Wang
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, China
| | - Katie L Stone
- Department of Research Institute, California Pacific Medical Center, San Francisco, CA, United States
| | - Zhengan Lu
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, Stockholm, Sweden
| | - Shanshan Tian
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, China
| | - Yongbo Zheng
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, China
| | - Bingxin Zhao
- Department of Statistics and Data Science, University of Pennsylvania, Philadelphia, PA, United States
| | - Yanping Bao
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China
| | - Le Shi
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, China
| | - Lin Lu
- Peking University Sixth Hospital, Peking University Institute of Mental Health, NHC Key Laboratory of Mental Health (Peking University), National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, China
- National Institute on Drug Dependence and Beijing Key Laboratory of Drug Dependence, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences and PKU-IDG/McGovern Institute for Brain Research, Peking University, Beijing, China
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Alipour M, Seok S, Mednick SC, Malerba P. A classification-based generative approach to selective targeting of global slow oscillations during sleep. Front Hum Neurosci 2024; 18:1342975. [PMID: 38415278 PMCID: PMC10896842 DOI: 10.3389/fnhum.2024.1342975] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Accepted: 01/30/2024] [Indexed: 02/29/2024] Open
Abstract
Background Given sleep's crucial role in health and cognition, numerous sleep-based brain interventions are being developed, aiming to enhance cognitive function, particularly memory consolidation, by improving sleep. Research has shown that Transcranial Alternating Current Stimulation (tACS) during sleep can enhance memory performance, especially when used in a closed-loop (cl-tACS) mode that coordinates with sleep slow oscillations (SOs, 0.5-1.5Hz). However, sleep tACS research is characterized by mixed results across individuals, which are often attributed to individual variability. Objective/Hypothesis This study targets a specific type of SOs, widespread on the electrode manifold in a short delay ("global SOs"), due to their close relationship with long-term memory consolidation. We propose a model-based approach to optimize cl-tACS paradigms, targeting global SOs not only by considering their temporal properties but also their spatial profile. Methods We introduce selective targeting of global SOs using a classification-based approach. We first estimate the current elicited by various stimulation paradigms, and optimize parameters to match currents found in natural sleep during a global SO. Then, we employ an ensemble classifier trained on sleep data to identify effective paradigms. Finally, the best stimulation protocol is determined based on classification performance. Results Our study introduces a model-driven cl-tACS approach that specifically targets global SOs, with the potential to extend to other brain dynamics. This method establishes a connection between brain dynamics and stimulation optimization. Conclusion Our research presents a novel approach to optimize cl-tACS during sleep, with a focus on targeting global SOs. This approach holds promise for improving cl-tACS not only for global SOs but also for other physiological events, benefiting both research and clinical applications in sleep and cognition.
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Affiliation(s)
- Mahmoud Alipour
- Center for Biobehavioral Health, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, OH, United States
- The Ohio State University School of Medicine, Columbus, OH, United States
| | - SangCheol Seok
- Center for Gene Therapy, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, OH, United States
| | - Sara C. Mednick
- Department of Cognitive Sciences, University of California, Irvine, Irvine CA, United States
| | - Paola Malerba
- Center for Biobehavioral Health, Abigail Wexner Research Institute, Nationwide Children’s Hospital, Columbus, OH, United States
- The Ohio State University School of Medicine, Columbus, OH, United States
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Wilckens KA, Habte RF, Dong Y, Stepan ME, Dessa KM, Whitehead AB, Peng CW, Fletcher ME, Buysse DJ. A pilot time-in-bed restriction intervention behaviorally enhances slow-wave activity in older adults. FRONTIERS IN SLEEP 2024; 2:1265006. [PMID: 38938690 PMCID: PMC11210605 DOI: 10.3389/frsle.2023.1265006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/29/2024]
Abstract
Introduction Identifying intervention methods that target sleep characteristics involved in memory processing is a priority for the field of cognitive aging. Older adults with greater sleep efficiency and non-rapid eye movement slow-wave activity (SWA) (0.5-4 Hz electroencephalographic activity) tend to exhibit better memory and cognitive abilities. Paradoxically, long total sleep times are consistently associated with poorer cognition in older adults. Thus, maximizing sleep efficiency and SWA may be a priority relative to increasing mere total sleep time. As clinical behavioral sleep treatments do not consistently enhance SWA, and propensity for SWA increases with time spent awake, we examined with a proof-of concept pilot intervention whether a greater dose of time-in-bed (TiB) restriction (75% of habitual TiB) would increase both sleep efficiency and SWA in older adults with difficulties staying asleep without impairing memory performance. Methods Participants were adults ages 55-80 with diary-reported sleep efficiency <90% and wake after sleep onset (WASO) >20 min. Sleep diary, actigraphy, polysomnography (PSG), and paired associate memory acquisition and retention were assessed before and after a week-long TiB restriction intervention (n = 30). TiB was restricted to 75% of diary-reported habitual TiB. A comparison group of n = 5 participants repeated assessments while following their usual sleep schedule to obtain preliminary estimates of effect sizes associated with repeated testing. Results Subjective and objective sleep measures robustly improved in the TiB restriction group for sleep quality, sleep depth, sleep efficiency and WASO, at the expense of TiB and time spent in N1 and N2 sleep. As hypothesized, SWA increased robustly with TiB restriction across the 0.5-4 Hz range, as well as subjective sleep depth, subjective and objective WASO. Despite increases in sleepiness ratings, no impairments were found in memory acquisition or retention. Conclusion A TiB restriction dose equivalent to 75% of habitual TiB robustly increased sleep continuity and SWA in older adults with sleep maintenance difficulties, without impairing memory performance. These findings may inform long-term behavioral SWA enhancement interventions aimed at improving memory performance and risk for cognitive impairments.
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Affiliation(s)
| | - Rima F. Habte
- Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Yue Dong
- School of Nursing, University of Pittsburgh, Pittsburgh, PA, United States
| | - Michelle E. Stepan
- School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
| | - Kibra M. Dessa
- Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Alexis B. Whitehead
- Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Christine W. Peng
- Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Mary E. Fletcher
- Department of Psychiatry, University of Pittsburgh Medical Center, Pittsburgh, PA, United States
| | - Daniel J. Buysse
- School of Medicine, University of Pittsburgh, Pittsburgh, PA, United States
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Ladenbauer J, Khakimova L, Malinowski R, Obst D, Tönnies E, Antonenko D, Obermayer K, Hanna J, Flöel A. Towards Optimization of Oscillatory Stimulation During Sleep. Neuromodulation 2023; 26:1592-1601. [PMID: 35981956 DOI: 10.1016/j.neurom.2022.05.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2021] [Revised: 05/13/2022] [Accepted: 05/16/2022] [Indexed: 11/28/2022]
Abstract
BACKGROUND Oscillatory rhythms during sleep, such as slow oscillations (SOs) and spindles and, most importantly, their coupling, are thought to underlie processes of memory consolidation. External slow oscillatory transcranial direct current stimulation (so-tDCS) with a frequency of 0.75 Hz has been shown to improve this coupling and memory consolidation; however, effects varied quite markedly between individuals, studies, and species. In this study, we aimed to determine how precisely the frequency of stimulation must match the naturally occurring SO frequency in individuals to best improve SO-spindle coupling. Moreover, we systematically tested stimulation durations necessary to induce changes. MATERIALS AND METHODS We addressed these questions by comparing so-tDCS with individualized frequency to standardized frequency of 0.75 Hz in a within-subject design with 28 older participants during napping while stimulation train durations were systematically varied between 30 seconds, 2 minutes, and 5 minutes. RESULTS Stimulation trains as short as 30 seconds were sufficient to modulate the coupling between SOs and spindle activity. Contrary to our expectations, so-tDCS with standardized frequency indicated stronger aftereffects regarding SO-spindle coupling than individualized frequency. Angle and variance of spindle maxima occurrence during the SO cycle were similarly modulated. CONCLUSIONS In sum, short stimulation trains were sufficient to induce significant changes in sleep physiology, allowing for more trains of stimulation, which provides methodological advantages and possibly even larger behavioral effects in future studies. Regarding individualized stimulation frequency, further options of optimization need to be investigated, such as closed-loop stimulation, to calibrate stimulation frequency to the SO frequency at the time of stimulation onset. CLINICAL TRIAL REGISTRATION The Clinicaltrials.gov registration number for the study is NCT04714879.
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Affiliation(s)
- Julia Ladenbauer
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Liliia Khakimova
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Robert Malinowski
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Daniela Obst
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Eric Tönnies
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Daria Antonenko
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Klaus Obermayer
- Fakultät IV and Bernstein Center for Computational Neuroscience, Technische Universität Berlin, Berlin, Germany
| | - Jeff Hanna
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany
| | - Agnes Flöel
- Department of Neurology, Universitätsmedizin Greifswald, Greifswald, Germany; German Centre for Neurodegenerative Diseases (DZNE) Greifswald, Greifswald, Germany.
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Lu H, Li J, Yang NS, Lam LCW, Ma SL, Wing YK, Zhang L. Using gamma-band transcranial alternating current stimulation (tACS) to improve sleep quality and cognition in patients with mild neurocognitive disorders due to Alzheimer's disease: A study protocol for a randomized controlled trial. PLoS One 2023; 18:e0289591. [PMID: 37540692 PMCID: PMC10403094 DOI: 10.1371/journal.pone.0289591] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 07/21/2023] [Indexed: 08/06/2023] Open
Abstract
BACKGROUND Sleep disturbances are highly prevalent in patients with age-related neurodegenerative diseases, which severely affect cognition and even lead to accumulated β-amyloid. Encouraging results from recent studies on transcranial direct current stimulation (tDCS) showed moderate positive effects on sleep quality in preclinical Alzheimer's disease (AD). Compared to tDCS, transcranial alternating current stimulation (tACS) enables the entrainment of neuronal activity with optimized focality through injecting electric current with a specific frequency and has significant enhancement effects on slow wave activities. METHODS AND DESIGN This is a randomized, double-blind, sham-controlled clinical trial comparing 40 Hz tACS with tDCS in mild neurocognitive disorders due to AD with sleep disturbances. Magnetic resonance imaging (MRI) data is used to construct personalized realistic head model. Treatment outcomes, including sleep quality, cognitive performance and saliva Aβ levels will be conducted at baseline, 4th week, 8th week, 12th week and 24th week. CONCLUSIONS It is expected that the repeated gamma-band tACS will show significant improvements in sleep quality and cognitive functions compared to tDCS and sham tDCS. The findings will provide high-level evidence and guide further advanced studies in the field of neurodegenerative diseases and sleep medicine. TRIAL REGISTRATION ClinicalTrials.gov Identifier: NCT05544201.
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Affiliation(s)
- Hanna Lu
- Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR, China
- The Affiliated Brain Hospital of Guangzhou Medical University, Guangzhou, China
| | - Jing Li
- Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Natalie Shu Yang
- Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Linda Chiu Wa Lam
- Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Suk Ling Ma
- Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Yun Kwok Wing
- Department of Psychiatry, The Chinese University of Hong Kong, Hong Kong SAR, China
| | - Li Zhang
- Department of Mechanical and Automation Engineering, The Chinese University of Hong Kong, Hong Kong SAR, China
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Closed-Loop tACS Delivered during Slow-Wave Sleep Reduces Retroactive Interference on a Paired-Associates Learning Task. Brain Sci 2023; 13:brainsci13030468. [PMID: 36979277 PMCID: PMC10046133 DOI: 10.3390/brainsci13030468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/03/2023] [Accepted: 03/06/2023] [Indexed: 03/12/2023] Open
Abstract
Previous studies have found a benefit of closed-loop transcranial alternating current stimulation (CL-tACS) matched to ongoing slow-wave oscillations (SWO) during sleep on memory consolidation for words in a paired associates task (PAT). Here, we examined the effects of CL-tACS in a retroactive interference PAT (ri-PAT) paradigm, where additional stimuli were presented to increase interference and reduce memory performance. Thirty-one participants were tested on a PAT before sleep, and CL-tACS was applied over the right and left DLPFC (F3 and F4) vs. mastoids for five cycles after detection of the onset of each discrete event of SWO during sleep. Participants were awoken the following morning, learned a new PAT list, and then were tested on the original list. There was a significant effect of stimulation condition (p = 0.04297; Cohen’s d = 0.768), where verum stimulation resulted in reduced retroactive interference compared with sham and a significant interaction of encoding strength and stimulation condition (p = 0.03591). Planned simple effects testing within levels of encoding revealed a significant effect of stimulation only for low-encoders (p = 0.0066; Cohen’s d = 1.075) but not high-encoders. We demonstrate here for the first time that CL-tACS during sleep can enhance the protective benefits on retroactive interference in participants who have lower encoding aptitude.
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8
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Effects of Transcranial Direct Current Stimulation on Sleep in Athletes: A Protocol of a Randomized Controlled Trial. J Clin Med 2022; 11:jcm11195883. [PMID: 36233749 PMCID: PMC9571881 DOI: 10.3390/jcm11195883] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 09/28/2022] [Accepted: 10/02/2022] [Indexed: 11/16/2022] Open
Abstract
Background: Sleep disturbances are common among athletes. There is recently a growing interest in improving sleep quality by using noninvasive brain stimulation techniques such as transcranial direct current stimulation (tDCS). We hypothesized that bilateral dorsolateral prefrontal cortex anodal tDCS could improve sleep in different sports athletes. A randomized controlled trial is to be conducted to test this hypothesis. Methods: Eighty-four athletes are selected based on specific eligibility criteria and randomly allocated to the intervention or control group. Each participant will receive a 20-min session of bilateral anodal tDCS with an intensity of 1.5 mA (0.057 mA/cm2) in density 3 times a week for 2 weeks. The tDCS current will be delivered only for 30 seconds in the control group. This study’s outcome is a set of subjective and objective sleep parameters. Conclusion: This study assessed the effect of a novel tDCS protocol represented by bilateral anodal stimulation and may result in important advances in sleep management among athletes. Because of the high incidence and impact of athletes’ poor sleep quality, it is particularly important to explore effective interventions. Trial Registration: ClinicalTrials.gov: NCT05318352.
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Slow-oscillatory tACS does not modulate human motor cortical response to repeated plasticity paradigms. Exp Brain Res 2022; 240:2965-2979. [PMID: 36173425 PMCID: PMC9587974 DOI: 10.1007/s00221-022-06462-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Accepted: 09/05/2022] [Indexed: 11/10/2022]
Abstract
Previous history of activity and learning modulates synaptic plasticity and can lead to saturation of synaptic connections. According to the synaptic homeostasis hypothesis, neural oscillations during slow-wave sleep play an important role in restoring plasticity within a functional range. However, it is not known whether slow-wave oscillations—without the concomitant requirement of sleep—play a causal role in human synaptic homeostasis. Here, we aimed to answer this question using transcranial alternating current stimulation (tACS) to induce slow-oscillatory activity in awake human participants. tACS was interleaved between two plasticity-inducing interventions: motor learning, and paired associative stimulation (PAS). The hypothesis tested was that slow-oscillatory tACS would prevent homeostatic interference between motor learning and PAS, and facilitate plasticity from these successive interventions. Thirty-six participants received sham and active fronto-motor tACS in two separate sessions, along with electroencephalography (EEG) recordings, while a further 38 participants received tACS through a control montage. Motor evoked potentials (MEPs) were recorded throughout the session to quantify plasticity changes after the different interventions, and the data were analysed with Bayesian statistics. As expected, there was converging evidence that motor training led to excitatory plasticity. Importantly, we found moderate evidence against an effect of active tACS in restoring PAS plasticity, and no evidence of lasting entrainment of slow oscillations in the EEG. This suggests that, under the conditions tested here, slow-oscillatory tACS does not modulate synaptic homeostasis in the motor system of awake humans.
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Abstract
Over the past few decades, the importance of sleep has become increasingly recognized for many physiologic functions, including cognition. Many studies have reported the deleterious effect of sleep loss or sleep disruption on cognitive performance. Beyond ensuring adequate sleep quality and duration, discovering methods to enhance sleep to augment its restorative effects is important to improve learning in many populations, such as the military, students, age-related cognitive decline, and cognitive disorders.
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Affiliation(s)
- Roneil G Malkani
- Division of Sleep Medicine, Department of Neurology, Center for Circadian and Sleep Medicine, Northwestern University Feinberg School of Medicine, 710 North Lake Shore Drive, Suite 525, Chicago, IL 60611, USA; Jesse Brown Veterans Affairs Medical Center, Chicago, IL 60612, USA.
| | - Phyllis C Zee
- Division of Sleep Medicine, Department of Neurology, Center for Circadian and Sleep Medicine, Northwestern University Feinberg School of Medicine, 710 North Lake Shore Drive, Suite 520, Chicago, IL 60611, USA
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McCarter SJ, Hagen PT, St Louis EK, Rieck TM, Haider CR, Holmes DR, Morgenthaler TI. Physiological markers of sleep quality: A scoping review. Sleep Med Rev 2022; 64:101657. [PMID: 35753151 DOI: 10.1016/j.smrv.2022.101657] [Citation(s) in RCA: 24] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Revised: 05/16/2022] [Accepted: 05/29/2022] [Indexed: 10/18/2022]
Abstract
Understanding the associations between adequate sleep, performance and health outcomes is vital, yet a major limitation in the design and interpretation of studies of sleep and performance is the variability of subjective and objective markers used to assess sleep quality. The aim of this scoping review is to investigate how various physiological signals recorded during sleep or wakefulness relate to objective measures of cognitive or physical performance and subjectively perceived sleep quality to inform conceptual understanding of the elusive, amorphous, and multi-dimensional construct of sleep quality. We also aimed to suggest priorities for future areas of research in sleep quality and performance. We searched six databases ultimately yielding 439 studies after duplicate removal. Sixty-five studies were selected for full review. In general, correlations between objectively measured sleep and objective performance or subjectively assessed sleep quality were weak to moderate. Slow wave sleep was moderately correlated with better performance on tasks of vigilance, motor speed, and executive function as well as better subjective sleep quality and feeling well-rested, suggesting that slow wave sleep may be important for sleep quality and optimal daytime performance. However, these findings were inconsistent across studies. Increased sleep fragmentation was associated with poorer subjective sleep quality in both polysomnographic and actigraphic studies. Studies which simultaneously assessed physiologic sleep measures, performance measures and subjective sleep perception were few, limiting the ability to evaluate correlations between subjective and objective outcomes concurrently in the same individuals. Factors influencing the relationship between sleep quality and performance include circadian variability, sleep inertia, and mismatch between sleep stages studied and outcome measures of choice. Ultimately, the determination of "quality sleep" remains largely subjective and inconsistently quantifiable by current measures. Methods evaluating sleep as a continuous measure rather than traditional sleep stages may provide an intriguing approach to future studies of sleep and performance. Future well-designed studies using novel measures of sleep or multimodal ambulatory wearables assessing the three domains of sleep and performance (objective sleep physiology, objective performance, and subjective sleep quality) are needed to better define quality sleep.
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Affiliation(s)
- Stuart J McCarter
- Center for Sleep Medicine, Mayo Clinic and Foundation, Rochester, MN, USA; Department of Neurology, Mayo Clinic and Foundation, Rochester, MN, USA.
| | - Philip T Hagen
- Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN, USA
| | - Erik K St Louis
- Center for Sleep Medicine, Mayo Clinic and Foundation, Rochester, MN, USA; Department of Neurology, Mayo Clinic and Foundation, Rochester, MN, USA; Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN, USA
| | - Thomas M Rieck
- Mayo Clinic Healthy Living Program, Mayo Clinic and Foundation, Rochester, MN, USA
| | - Clifton R Haider
- Section of Biostatistics, Mayo Clinic and Foundation, Rochester, MN, USA
| | - David R Holmes
- Section of Biostatistics, Mayo Clinic and Foundation, Rochester, MN, USA
| | - Timothy I Morgenthaler
- Center for Sleep Medicine, Mayo Clinic and Foundation, Rochester, MN, USA; Department of Internal Medicine, Mayo Clinic and Foundation, Rochester, MN, USA; Department of Pulmonology, Mayo Clinic and Foundation, Rochester, MN, USA
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Examining the relationship between working memory consolidation and long-term consolidation. Psychon Bull Rev 2022; 29:1625-1648. [PMID: 35357669 DOI: 10.3758/s13423-022-02084-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/04/2022] [Indexed: 11/08/2022]
Abstract
An emerging area of research is focused on the relationship between working memory and long-term memory and the likely overlap between these processes. Of particular interest is how some information first maintained in working memory is retained for longer periods and eventually preserved in long-term memory. The process of stabilizing transient memory representations for lasting retention is referred to as consolidation in both the working memory and long-term memory literature, although these have historically been viewed as independent constructs. The present review aims to investigate the relationship between working memory consolidation and long-term memory consolidation, which both have rich, but distinct, histories. This review provides an overview of the proposed models and neural mechanisms of both types of consolidation, as well as clinical findings related to consolidation and potential approaches for the manipulation of consolidation. Finally, two hypotheses are proposed to explain the relationship between working memory consolidation and long-term memory consolidation.
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13
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Mathematical Model Insights into EEG Origin under Transcranial Direct Current Stimulation (tDCS) in the Context of Psychosis. J Clin Med 2022; 11:jcm11071845. [PMID: 35407453 PMCID: PMC8999473 DOI: 10.3390/jcm11071845] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Revised: 03/12/2022] [Accepted: 03/22/2022] [Indexed: 02/04/2023] Open
Abstract
Schizophrenia is a psychotic disease that develops progressively over years with a transition from prodromal to psychotic state associated with a disruption in brain activity. Transcranial Direct Current Stimulation (tDCS), known to alleviate pharmaco-resistant symptoms in patients suffering from schizophrenia, promises to prevent such a psychotic transition. To understand better how tDCS affects brain activity, we propose a neural cortico-thalamo-cortical (CTC) circuit model involving the Ascending Reticular Arousal System (ARAS) that permits to describe major impact features of tDCS, such as excitability for short-duration stimulation and electroencephalography (EEG) power modulation for long-duration stimulation. To this end, the mathematical model relates stimulus duration and Long-Term Plasticity (LTP) effect, in addition to describing the temporal LTP decay after stimulus offset. This new relation promises to optimize future stimulation protocols. Moreover, we reproduce successfully EEG-power modulation under tDCS in a ketamine-induced psychosis model and confirm the N-methyl-d-aspartate (NMDA) receptor hypofunction hypothesis in the etiopathophysiology of schizophrenia. The model description points to an important role of the ARAS and the δ-rhythm synchronicity in CTC circuit in early-stage psychosis.
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14
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Siegert A, Diedrich L, Antal A. New Methods, Old Brains-A Systematic Review on the Effects of tDCS on the Cognition of Elderly People. Front Hum Neurosci 2021; 15:730134. [PMID: 34776903 PMCID: PMC8578968 DOI: 10.3389/fnhum.2021.730134] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2021] [Accepted: 09/28/2021] [Indexed: 11/13/2022] Open
Abstract
The world's population is aging. With this comes an increase in the prevalence of age-associated diseases, which amplifies the need for novel treatments to counteract cognitive decline in the elderly. One of the recently discussed non-pharmacological approaches is transcranial direct current stimulation (tDCS). TDCS delivers weak electric currents to the brain, thereby modulating cortical excitability and activity. Recent evidence suggests that tDCS, mainly with anodal currents, can be a powerful means to non-invasively enhance cognitive functions in elderly people with age-related cognitive decline. Here, we screened a recently developed tDCS database (http://tdcsdatabase.com) that is an open access source of published tDCS papers and reviewed 16 studies that applied tDCS to healthy older subjects or patients suffering from Alzheimer's Disease or pre-stages. Evaluating potential changes in cognitive abilities we focus on declarative and working memory. Aiming for more standardized protocols, repeated tDCS applications (2 mA, 30 min) over the left dorso-lateral prefrontal cortex (LDLPFC) of elderly people seem to be one of the most efficient non-invasive brain stimulation (NIBS) approaches to slow progressive cognitive deterioration. However, inter-subject variability and brain state differences in health and disease restrict the possibility to generalize stimulation methodology and increase the necessity of personalized protocol adjustment by means of improved neuroimaging techniques and electrical field modeling.
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Affiliation(s)
- Anna Siegert
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Lukas Diedrich
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
| | - Andrea Antal
- Department of Neurology, University Medical Center Göttingen, Göttingen, Germany
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15
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Ladenbauer J, Ladenbauer J, Külzow N, Flöel A. Memory-relevant nap sleep physiology in healthy and pathological aging. Sleep 2021; 44:6066546. [PMID: 33406266 DOI: 10.1093/sleep/zsab002] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 11/30/2020] [Indexed: 11/13/2022] Open
Abstract
STUDY OBJECTIVES Aging is associated with detrimental changes in sleep physiology, a process accelerated in Alzheimer's disease. Fine-tuned temporal interactions of non-rapid eye movement slow oscillations and spindles were shown to be particularly important for memory consolidation, and to deteriorate in healthy older adults. Whether this oscillatory interaction further decline in early stages of Alzheimer's disease such as mild cognitive impairment has not been investigated to date, but may have important therapeutic implications. METHODS Here, we assessed differences in sleep architecture and memory-relevant slow oscillation, sleep spindles and their functional coupling during a 90-min nap between healthy young and older adults, and in older patients with mild cognitive impairment. Furthermore, associations of nap-sleep characteristics with sleep-dependent memory performance change were evaluated. RESULTS We found significant differences between young and older healthy adults, and between young adults and patients with mild cognitive impairment, but not between healthy older adults and patients for several sleep metrics, including slow oscillation-spindle coupling. Moreover, sleep-dependent retention of verbal memories was significantly higher in young healthy adults versus older adults with and without mild cognitive impairment, but no difference between the two older groups was observed. Associations with sleep metrics were only found for pre-nap memory performances. CONCLUSIONS In conclusion, our results indicate changes in nap sleep physiology and sleep-related memory consolidation in older adults with and without mild cognitive impairment. Thus, interventions targeted at improving sleep physiology may help to reduce memory decline in both groups, but our study does not indicate additional benefits for patients with mild cognitive impairment. CLINICAL TRAIL REGISTRATION Effects of Brain Stimulation During Daytime Nap on Memory Consolidation in Younger, Healthy Subjects: https://clinicaltrials.gov/ct2/show/NCT01840865; NCT01840865. Effects of Brain Stimulation During a Daytime Nap on Memory Consolidation in Older Adults; https://clinicaltrials.gov/ct2/show/study/NCT01840839?term=01840839&draw=2&rank=1; NCT01840839. Effects of Brain Stimulation During a Daytime Nap on Memory Consolidation in Patients With Mild Cognitive Impairment; https://clinicaltrials.gov/ct2/show/NCT01782365?term=01782365&draw=2&rank=1; NCT01782365.
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Affiliation(s)
- Julia Ladenbauer
- Department of Neurology, University Medicine Greifswald, Greifswald, Germany.,Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
| | - Josef Ladenbauer
- Laboratoire de Neurosciences Cognitives et Computationnelles, INSERM U960, École Normale Supérieure, PSL Research University, Paris, France
| | - Nadine Külzow
- Kliniken Beelitz GmbH, Neurologische Rehabilitation, Beelitz-Heilstätten, Germany
| | - Agnes Flöel
- Department of Neurology, University Medicine Greifswald, Greifswald, Germany.,Department of Neurology, Charité Universitätsmedizin Berlin, Berlin, Germany
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16
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Rackoll T, Neumann K, Passmann S, Grittner U, Külzow N, Ladenbauer J, Flöel A. Applying time series analyses on continuous accelerometry data-A clinical example in older adults with and without cognitive impairment. PLoS One 2021; 16:e0251544. [PMID: 33984029 PMCID: PMC8118312 DOI: 10.1371/journal.pone.0251544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 04/29/2021] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION Many 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). METHODS Data 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. RESULTS Information 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. DISCUSSION Using 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 TRIALS Effects 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.
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Affiliation(s)
- Torsten Rackoll
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, NeuroCure Excellence Cluster (NCRC), Berlin, Germany
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Center for Stroke Research Berlin (CSB), Berlin, Germany
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, BIH QUEST-Center for Transforming Biomedical Research, Berlin, Germany
| | - Konrad Neumann
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biometry and Clinical Epidemiology, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
| | - Sven Passmann
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, NeuroCure Excellence Cluster (NCRC), Berlin, Germany
| | - Ulrike Grittner
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Biometry and Clinical Epidemiology, Berlin, Germany
- Berlin Institute of Health (BIH), Berlin, Germany
| | - Nadine Külzow
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, NeuroCure Excellence Cluster (NCRC), Berlin, Germany
- Kliniken Beelitz GmbH, Beelitz-Heilstätten, Germany
| | - Julia Ladenbauer
- Department of Neurology, University Medicine Greifswald, Greifswald, Germany
| | - Agnes Flöel
- Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Center for Stroke Research Berlin (CSB), Berlin, Germany
- Department of Neurology, University Medicine Greifswald, Greifswald, Germany
- German Center for Neurodegenerative Diseases (DZNE), Partner Site, Rostock/Greifswald, Germany
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17
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Cordone S, Scarpelli S, Alfonsi V, De Gennaro L, Gorgoni M. Sleep-Based Interventions in Alzheimer's Disease: Promising Approaches from Prevention to Treatment along the Disease Trajectory. Pharmaceuticals (Basel) 2021; 14:ph14040383. [PMID: 33921870 PMCID: PMC8073746 DOI: 10.3390/ph14040383] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 04/10/2021] [Accepted: 04/16/2021] [Indexed: 02/07/2023] Open
Abstract
The multifactorial nature of Alzheimer’s disease (AD) has led scientific researchers to focus on the modifiable and treatable risk factors of AD. Sleep fits into this context, given the bidirectional relationship with AD confirmed by several studies over the last years. Sleep disorders appear at an early stage of AD and continue throughout the entire course of the pathology. Specifically, sleep abnormalities, such as more fragmented sleep, increase in time of awakenings, worsening of sleep quality and primary sleep disorders raise with the severity and progression of AD. Intervening on sleep, therefore, means acting both with prevention strategies in the pre-clinical phase and with treatments during the course of the disease. This review explores sleep disturbances in the different stages of AD, starting from the pre-clinical stage. Particular attention is given to the empirical evidence investigating obstructive sleep apnea (OSA) disorder and the mechanisms overlapping and sharing with AD. Next, we discuss sleep-based intervention strategies in the healthy elderly population, mild cognitive impairment (MCI) and AD patients. We mention interventions related to behavioral strategies, combination therapies, and bright light therapy, leaving extensive space for new and raising evidence on continuous positive air pressure (CPAP) treatment effectiveness. Finally, we clarify the role of NREM sleep across the AD trajectory and consider the most recent studies based on the promising results of NREM sleep enhancement, which use innovative experimental designs and techniques.
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Affiliation(s)
- Susanna Cordone
- UniCamillus, Saint Camillus International University of Health Sciences, 00131 Rome, Italy;
| | - Serena Scarpelli
- Department of Psychology, University of Rome “Sapienza”, 00185 Rome, Italy; (S.S.); (M.G.)
| | | | - Luigi De Gennaro
- Department of Psychology, University of Rome “Sapienza”, 00185 Rome, Italy; (S.S.); (M.G.)
- IRCCS Fondazione Santa Lucia, 00179 Rome, Italy;
- Correspondence:
| | - Maurizio Gorgoni
- Department of Psychology, University of Rome “Sapienza”, 00185 Rome, Italy; (S.S.); (M.G.)
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18
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Schneider J, Lewis PA, Koester D, Born J, Ngo HVV. Susceptibility to auditory closed-loop stimulation of sleep slow oscillations changes with age. Sleep 2021; 43:5850478. [PMID: 32562487 PMCID: PMC7734479 DOI: 10.1093/sleep/zsaa111] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 05/10/2020] [Indexed: 11/20/2022] Open
Abstract
Study Objectives Cortical slow oscillations (SOs) and thalamocortical sleep spindles hallmark slow wave sleep and facilitate memory consolidation, both of which are reduced with age. Experiments utilizing auditory closed-loop stimulation to enhance these oscillations showed great potential in young and older subjects. However, the magnitude of responses has yet to be compared between these age groups. We examined the possibility of enhancing SOs and performance on different memory tasks in a healthy middle-aged population using this stimulation and contrast effects to younger adults. Methods In a within-subject design, 17 subjects (55.7 ± 1.0 years) received auditory stimulation in synchrony with SO up-states, which was compared to a no-stimulation sham condition. Overnight memory consolidation was assessed for declarative word-pairs and procedural finger-tapping skill. Post-sleep encoding capabilities were tested with a picture recognition task. Electrophysiological effects of stimulation were compared to a previous younger cohort (n = 11, 24.2 ± 0.9 years). Results Overnight retention and post-sleep encoding performance of the older cohort revealed no beneficial effect of stimulation, which contrasts with the enhancing effect the same stimulation protocol had in our younger cohort. Auditory stimulation prolonged endogenous SO trains and induced sleep spindles phase-locked to SO up-states in the older population. However, responses were markedly reduced compared to younger subjects. Additionally, the temporal dynamics of stimulation effects on SOs and spindles differed between age groups. Conclusions Our findings suggest that the susceptibility to auditory stimulation during sleep drastically changes with age and reveal the difficulties of translating a functional protocol from younger to older populations.
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Affiliation(s)
- Jules Schneider
- School of Biological Sciences, University of Manchester, Manchester, UK
- School of Psychology, Cardiff University, Cardiff, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - Penelope A Lewis
- School of Biological Sciences, University of Manchester, Manchester, UK
- School of Psychology, Cardiff University, Cardiff, UK
- Corresponding authors. Hong-Viet V. Ngo, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands. ; Penelope A. Lewis, School of Psychology, Cardiff University, Cardiff, UK.
| | - Dominik Koester
- Institute for Medical Psychology and Behavioural Neurobiology, University of Tübingen, Tübingen, Germany
| | - Jan Born
- Institute for Medical Psychology and Behavioural Neurobiology, University of Tübingen, Tübingen, Germany
- Centre for Integrative Neuroscience, University of Tübingen, Tübingen, Germany
| | - Hong-Viet V Ngo
- Institute for Medical Psychology and Behavioural Neurobiology, University of Tübingen, Tübingen, Germany
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
- Corresponding authors. Hong-Viet V. Ngo, Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Kapittelweg 29, 6525 EN Nijmegen, The Netherlands. ; Penelope A. Lewis, School of Psychology, Cardiff University, Cardiff, UK.
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19
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The effects of non-invasive brain stimulation on sleep disturbances among different neurological and neuropsychiatric conditions: A systematic review. Sleep Med Rev 2021; 55:101381. [DOI: 10.1016/j.smrv.2020.101381] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2020] [Revised: 04/17/2020] [Accepted: 06/09/2020] [Indexed: 12/11/2022]
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20
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Fehér KD, Wunderlin M, Maier JG, Hertenstein E, Schneider CL, Mikutta C, Züst MA, Klöppel S, Nissen C. Shaping the slow waves of sleep: A systematic and integrative review of sleep slow wave modulation in humans using non-invasive brain stimulation. Sleep Med Rev 2021; 58:101438. [PMID: 33582581 DOI: 10.1016/j.smrv.2021.101438] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Revised: 10/14/2020] [Accepted: 11/10/2020] [Indexed: 01/19/2023]
Abstract
The experimental study of electroencephalographic slow wave sleep (SWS) stretches over more than half a century and has corroborated its importance for basic physiological processes, such as brain plasticity, metabolism and immune system functioning. Alterations of SWS in aging or pathological conditions suggest that modulating SWS might constitute a window for clinically relevant interventions. This work provides a systematic and integrative review of SWS modulation through non-invasive brain stimulation in humans. A literature search using PubMed, conducted in May 2020, identified 3220 studies, of which 82 fulfilled inclusion criteria. Three approaches have been adopted to modulate the macro- and microstructure of SWS, namely auditory, transcranial electrical and transcranial magnetic stimulation. Our current knowledge about the modulatory mechanisms, the space of stimulation parameters and the physiological and behavioral effects are reported and evaluated. The integration of findings suggests that sleep slow wave modulation bears the potential to promote our understanding of the functions of SWS and to develop new treatments for conditions of disrupted SWS.
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Affiliation(s)
- Kristoffer D Fehér
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Switzerland
| | - Marina Wunderlin
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Switzerland
| | - Jonathan G Maier
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Switzerland
| | - Elisabeth Hertenstein
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Switzerland
| | - Carlotta L Schneider
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Switzerland
| | - Christian Mikutta
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Switzerland; Privatklinik Meiringen, Meiringen, Switzerland
| | - Marc A Züst
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Switzerland
| | - Stefan Klöppel
- University Hospital of Old Age Psychiatry and Psychotherapy, University of Bern, Switzerland
| | - Christoph Nissen
- University Hospital of Psychiatry and Psychotherapy, University of Bern, Switzerland.
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21
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Dondé C, Brunelin J, Micoulaud-Franchi JA, Maruani J, Lejoyeux M, Polosan M, Geoffroy PA. The Effects of Transcranial Electrical Stimulation of the Brain on Sleep: A Systematic Review. Front Psychiatry 2021; 12:646569. [PMID: 34163380 PMCID: PMC8215269 DOI: 10.3389/fpsyt.2021.646569] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/27/2020] [Accepted: 04/19/2021] [Indexed: 01/23/2023] Open
Abstract
Transcranial Electrical Stimulation (tES) is a promising non-invasive brain modulation tool. Over the past years, there have been several attempts to modulate sleep with tES-based approaches in both the healthy and pathological brains. However, data about the impact on measurable aspects of sleep remain scattered between studies, which prevent us from drawing firm conclusions. We conducted a systematic review of studies that explored the impact of tES on neurophysiological sleep oscillations, sleep patterns measured objectively with polysomnography, and subjective psychometric assessments of sleep in both healthy and clinical samples. We searched four main electronic databases to identify studies until February 2020. Forty studies were selected including 511 healthy participants and 452 patients. tES can modify endogenous brain oscillations during sleep. Results concerning changes in sleep patterns are conflicting, whereas subjective assessments show clear improvements after tES. Possible stimulation-induced mechanisms within specific cortico-subcortical sleep structures and networks are discussed. Although these findings cannot be directly transferred to the clinical practice and sleep-enhancing devices development for healthy populations, they might help to pave the way for future researches in these areas. PROSPERO registration number 178910.
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Affiliation(s)
- Clément Dondé
- University Grenoble Alpes, Grenoble, France.,U1216 INSERM, Grenoble Institut of Neuroscience, La Tronche, France.,Psychiatry Department, CHU Grenoble Alpes, Grenoble, France
| | - Jerome Brunelin
- INSERM U1028, CNRS UMR5292, Lyon Neuroscience Research Center, PSY-R2 Team, Lyon, France.,Lyon University, Lyon, France.,Centre Hospitalier le Vinatier, Batiment 416, Bron, France
| | - Jean-Arthur Micoulaud-Franchi
- University Sleep Clinic, Services of Functional Exploration of the Nervous System, University Hospital of Bordeaux, Bordeaux, France.,USR CNRS 3413 SANPSY, University Hospital Pellegrin, University of Bordeaux, Bordeaux, France
| | - Julia Maruani
- Département de Psychiatrie et de Médecine Addictologique, Hôpital Fernand Widal, Assistance Publique des Hôpitaux de Paris (APHP), Paris, France.,Université de Paris, Paris, France.,INSERM U1144, Optimisation Thérapeutique en Neuropsychopharmacologie, Paris, France
| | - Michel Lejoyeux
- Paris Diderot University-Paris VII, 5 Rue Thomas Mann, Paris, France.,University Hospital Bichat-Claude Bernard, 46 rue Henri Huchard, Paris, France
| | - Mircea Polosan
- University Grenoble Alpes, Grenoble, France.,U1216 INSERM, Grenoble Institut of Neuroscience, La Tronche, France.,Psychiatry Department, CHU Grenoble Alpes, Grenoble, France
| | - Pierre A Geoffroy
- Paris Diderot University-Paris VII, 5 Rue Thomas Mann, Paris, France.,University Hospital Bichat-Claude Bernard, 46 rue Henri Huchard, Paris, France.,Université de Paris, NeuroDiderot, Inserm, Paris, France
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22
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Romanella SM, Roe D, Tatti E, Cappon D, Paciorek R, Testani E, Rossi A, Rossi S, Santarnecchi E. The Sleep Side of Aging and Alzheimer's Disease. Sleep Med 2021; 77:209-225. [PMID: 32912799 PMCID: PMC8364256 DOI: 10.1016/j.sleep.2020.05.029] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Revised: 05/13/2020] [Accepted: 05/19/2020] [Indexed: 01/23/2023]
Abstract
As we age, sleep patterns undergo significant modifications in micro and macrostructure, worsening cognition and quality of life. These are associated with remarkable brain changes, like deterioration in synaptic plasticity, gray and white matter, and significant modifications in hormone levels. Sleep alterations are also a core component of mild cognitive impairment (MCI) and Alzheimer's Disease (AD). AD night time is characterized by a gradual decrease in slow-wave activity and a substantial reduction of REM sleep. Sleep abnormalities can accelerate AD pathophysiology, promoting the accumulation of amyloid-β (Aβ) and phosphorylated tau. Thus, interventions that target sleep disturbances in elderly people and MCI patients have been suggested as a possible strategy to prevent or decelerate conversion to dementia. Although cognitive-behavioral therapy and pharmacological medications are still first-line treatments, despite being scarcely effective, new interventions have been proposed, such as sensory stimulation and Noninvasive Brain Stimulation (NiBS). The present review outlines the current state of the art of the relationship between sleep modifications in healthy aging and the neurobiological mechanisms underlying age-related changes. Furthermore, we provide a critical analysis showing how sleep abnormalities influence the prognosis of AD pathology by intensifying Aβ and tau protein accumulation. We discuss potential therapeutic strategies to target sleep disruptions and conclude that there is an urgent need for testing new therapeutic sleep interventions.
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Affiliation(s)
- S M Romanella
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
| | - D Roe
- Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - E Tatti
- Department of Molecular, Cellular & Biomedical Sciences, CUNY, School of Medicine, New York, NY, USA
| | - D Cappon
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - R Paciorek
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - E Testani
- Sleep Medicine Center, Department of Neurology, Policlinico Santa Maria Le Scotte, Siena, Italy
| | - A Rossi
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Human Physiology Section, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - S Rossi
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Human Physiology Section, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - E Santarnecchi
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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23
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Romanella SM, Sprugnoli G, Ruffini G, Seyedmadani K, Rossi S, Santarnecchi E. Noninvasive Brain Stimulation & Space Exploration: Opportunities and Challenges. Neurosci Biobehav Rev 2020; 119:294-319. [PMID: 32937115 PMCID: PMC8361862 DOI: 10.1016/j.neubiorev.2020.09.005] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Revised: 05/22/2020] [Accepted: 09/03/2020] [Indexed: 01/11/2023]
Abstract
As NASA prepares for longer space missions aiming for the Moon and Mars, astronauts' health and performance are becoming a central concern due to the threats associated with galactic cosmic radiation, unnatural gravity fields, and life in extreme environments. In space, the human brain undergoes functional and structural changes related to fluid shift and changes in intracranial pressure. Behavioral abnormalities, such as cognitive deficits, sleep disruption, and visuomotor difficulties, as well as psychological effects, are also an issue. We discuss opportunities and challenges of noninvasive brain stimulation (NiBS) methods - including transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (tES) - to support space exploration in several ways. NiBS includes safe and portable techniques already applied in a wide range of cognitive and motor domains, as well as therapeutically. NiBS could be used to enhance in-flight performance, supporting astronauts during pre-flight Earth-based training, as well as to identify biomarkers of post-flight brain changes for optimization of rehabilitation/compensatory strategies. We review these NiBS techniques and their effects on brain physiology, psychology, and cognition.
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Affiliation(s)
- S M Romanella
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
| | - G Sprugnoli
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA; Radiology Unit, Department of Medicine and Surgery, University of Parma, Parma, Italy
| | - G Ruffini
- Neuroelectrics Corporation, Cambridge, MA, USA
| | - K Seyedmadani
- University Space Research Association NASA Johnson Space Center, Houston, TX, USA; Ann and H.J. Smead Aerospace Engineering Sciences, University of Colorado, Boulder, CO, USA
| | - S Rossi
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Human Physiology Section, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - E Santarnecchi
- Siena Brain Investigation & Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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Goldthorpe RA, Rapley JM, Violante IR. A Systematic Review of Non-invasive Brain Stimulation Applications to Memory in Healthy Aging. Front Neurol 2020; 11:575075. [PMID: 33193023 PMCID: PMC7604325 DOI: 10.3389/fneur.2020.575075] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Accepted: 09/11/2020] [Indexed: 12/15/2022] Open
Abstract
It has long been acknowledged that memory changes over the course of one's life, irrespective of diseases like dementia. Approaches to mitigate these changes have however yielded mixed results. Brain stimulation has been identified as one novel approach of augmenting older adult's memory. Thus far, such approaches have however been nuanced, targeting different memory domains with different methodologies. This has produced an amalgam of research with an unclear image overall. This systematic review therefore aims to clarify this landscape, evaluating, and interpreting available research findings in a coherent manner. A systematic search of relevant literature was conducted across Medline, PsycInfo, Psycarticles and the Psychology and Behavioral Sciences Collection, which uncovered 44 studies employing non-invasive electrical brain stimulation in healthy older adults. All studies were of generally good quality spanning numerous memory domains. Within these, evidence was found for non-invasive brain stimulation augmenting working, episodic, associative, semantic, and procedural memory, with the first three domains having the greatest evidence base. Key sites for stimulation included the left dorsolateral prefrontal cortex (DLPFC), temporoparietal region, and primary motor cortex, with transcranial direct current stimulation (tDCS) holding the greatest literature base. Inconsistencies within the literature are highlighted and interpreted, however this discussion was constrained by potential confounding variables within the literature, a risk of bias, and challenges defining research aims and results. Non-invasive brain stimulation often did however have a positive and predictable impact on older adult's memory, and thus warrants further research to better understand these effects.
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Affiliation(s)
| | | | - Ines R. Violante
- School of Psychology, University of Surrey, Guildford, United Kingdom
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25
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McIntire LK, McKinley RA, Goodyear C, McIntire JP. The Effects of Anodal Transcranial Direct Current Stimulation on Sleep Time and Efficiency. Front Hum Neurosci 2020; 14:357. [PMID: 33192380 PMCID: PMC7481387 DOI: 10.3389/fnhum.2020.00357] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2020] [Accepted: 08/06/2020] [Indexed: 11/13/2022] Open
Abstract
A single session of anodal transcranial direct current stimulation (tDCS) has been shown to increase arousal in healthy participants for up to 24 h post-stimulation. However, little is known about the effects of tDCS on subsequent sleep in this population. Based on previous clinical studies, we hypothesized that anodal stimulation to the left dorsolateral prefrontal cortex (lDLPFC) would produce higher arousal with decreased sleep time and stimulation to the primary motor cortex (M1) would have the converse effect. Thirty-six active duty military were randomized into one of three groups (n = 12/group); active anodal tDCS over the lDLPFC, active anodal tDCS over left M1, or sham tDCS. Participants answered questionnaires 3 times a day and wore a wrist activity monitor (WAM) to measure sleep time and efficiency for 3 weeks. On weeks 2 and 3 (order counterbalance), participants received stimulation at 1800 h before 26 h of sustained wakefulness testing (sleep deprived) and at 1800 h without sleep deprivation (non-sleep deprived). There were no significant effects for the non-sleep deprived portion of testing. For the sleep deprived portion of testing, there were main effects of group and night on sleep time. The DLPFC group slept less than the other groups on the second and third night following stimulation. There is no negative effect on mood or sleep quality from a single dose of tDCS when participants have normal sleep patterns (i.e., non-sleep deprived portion of testing). The results suggest that stimulation may result in faster recovery from fatigue caused by acute periods of sleep deprivation, as their recovery sleep periods were less.
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Affiliation(s)
- Lindsey K McIntire
- Infoscitex, Inc., Wright-Patterson Air Force Base, Dayton, OH, United States
| | - R Andy McKinley
- Air Force Research Laboratory/Applied Neuroscience Branch, Wright-Patterson Air Force Base, Dayton, OH, United States
| | - Chuck Goodyear
- Infoscitex, Inc., Wright-Patterson Air Force Base, Dayton, OH, United States
| | - John P McIntire
- Air Force Research Laboratory/Security and Intelligence Branch, Wright-Patterson Air Force Base, Dayton, OH, United States
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Muehlroth BE, Rasch B, Werkle-Bergner M. Episodic memory consolidation during sleep in healthy aging. Sleep Med Rev 2020; 52:101304. [DOI: 10.1016/j.smrv.2020.101304] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 03/03/2020] [Accepted: 03/04/2020] [Indexed: 11/29/2022]
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Romanella SM, Roe D, Paciorek R, Cappon D, Ruffini G, Menardi A, Rossi A, Rossi S, Santarnecchi E. Sleep, Noninvasive Brain Stimulation, and the Aging Brain: Challenges and Opportunities. Ageing Res Rev 2020; 61:101067. [PMID: 32380212 PMCID: PMC8363192 DOI: 10.1016/j.arr.2020.101067] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2019] [Revised: 02/26/2020] [Accepted: 04/04/2020] [Indexed: 02/06/2023]
Abstract
As we age, sleep patterns undergo severe modifications of their micro and macrostructure, with an overall lighter and more fragmented sleep structure. In general, interventions targeting sleep represent an excellent opportunity not only to maintain life quality in the healthy aging population, but also to enhance cognitive performance and, when pathology arises, to potentially prevent/slow down conversion from e.g. Mild Cognitive Impairment (MCI) to Alzheimer's Disease (AD). Sleep abnormalities are, in fact, one of the earliest recognizable biomarkers of dementia, being also partially responsible for a cascade of cortical events that worsen dementia pathophysiology, including impaired clearance systems leading to build-up of extracellular amyloid-β (Aβ) peptide and intracellular hyperphosphorylated tau proteins. In this context, Noninvasive Brain Stimulation (NiBS) techniques, such as transcranial electrical stimulation (tES) and transcranial magnetic stimulation (TMS), may help investigate the neural substrates of sleep, identify sleep-related pathology biomarkers, and ultimately help patients and healthy elderly individuals to restore sleep quality and cognitive performance. However, brain stimulation applications during sleep have so far not been fully investigated in healthy elderly cohorts, nor tested in AD patients or other related dementias. The manuscript discusses the role of sleep in normal and pathological aging, reviewing available evidence of NiBS applications during both wakefulness and sleep in healthy elderly individuals as well as in MCI/AD patients. Rationale and details for potential future brain stimulation studies targeting sleep alterations in the aging brain are discussed, including enhancement of cognitive performance, overall quality of life as well as protein clearance.
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Affiliation(s)
- Sara M Romanella
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy
| | - Daniel Roe
- Beth Israel Deaconess Medical Center, Boston, MA, USA
| | - Rachel Paciorek
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Davide Cappon
- Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | | | - Arianna Menardi
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Padova Neuroscience Center, Department of Neuroscience, University of Padova, Padova, Italy
| | - Alessandro Rossi
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Human Physiology Section, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy
| | - Simone Rossi
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Human Physiology Section, Department of Medicine, Surgery and Neuroscience, University of Siena, Siena, Italy; Siena Robotics and Systems Lab (SIRS-Lab), Engineering and Mathematics Department, University of Siena, Siena, Italy
| | - Emiliano Santarnecchi
- Siena Brain Investigation and Neuromodulation Lab (Si-BIN Lab), Department of Medicine, Surgery and Neuroscience, Neurology and Clinical Neurophysiology Section, University of Siena, Italy; Berenson-Allen Center for Noninvasive Brain Stimulation, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
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Sandrini M, Manenti R, Sahin H, Cotelli M. Effects of transcranial electrical stimulation on episodic memory in physiological and pathological ageing. Ageing Res Rev 2020; 61:101065. [PMID: 32275953 DOI: 10.1016/j.arr.2020.101065] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 03/04/2020] [Accepted: 04/01/2020] [Indexed: 12/29/2022]
Abstract
Memory for personally-relevant past events (episodic memory) is critical for activities of daily living. Decline in this type of declarative long-term memory is a common characteristic of healthy ageing, a process accelerated in patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). Transcranial electrical stimulation (tES) has been used as a strategy to ameliorate episodic memory. Here, we critically review studies investigating whether tES may improve episodic memory in physiological and pathological ageing. Most of the studies suggest that tES over the prefrontal or temporoparietal cortices can have a positive effect on episodic memory, but the transfer to improvement of execution of daily living activities is still unknown. Further work is needed to better understand the mechanisms underlying the effects of stimulation, combine tES with neuroimaging and optimizing the dosing of stimulation. Future studies should also investigate the optimal timing of stimulation and the combination with medications to induce long-lasting beneficial effects in pathological ageing. More open science efforts should be done to improve rigor and reliability of tES in ageing research.
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Manoach DS, Mylonas D, Baxter B. Targeting sleep oscillations to improve memory in schizophrenia. Schizophr Res 2020; 221:63-70. [PMID: 32014359 PMCID: PMC7316628 DOI: 10.1016/j.schres.2020.01.010] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 01/06/2020] [Accepted: 01/09/2020] [Indexed: 12/26/2022]
Abstract
Although schizophrenia is defined by waking phenomena, a growing literature documents a deficit in sleep spindles, a defining oscillation of stage 2 non-rapid eye movement sleep. Compelling evidence supports an important role for spindles in cognition, and particularly memory. In schizophrenia, although the spindle deficit correlates with impaired sleep-dependent memory consolidation, recent clinical trials find that increasing spindles does not improve memory. This may reflect that sleep-dependent memory consolidation relies not on spindles alone, but also on their precise temporal coordination with cortical slow oscillations and hippocampal sharp-wave ripples. Consequently, interventions to improve memory in schizophrenia must not only increase spindles, but also preserve or enhance slow oscillations, hippocampal ripples and their temporal relations. Because hippocampal ripples and the activity of the thalamic spindle generator are difficult to measure noninvasively, screening potential interventions requires complementary animal and human studies. In this review we (i) propose that sleep oscillations are novel pathophysiological targets for therapy to improve cognition in schizophrenia; (ii) summarize our understanding of how these oscillations interact to consolidate memory; (iii) suggest that a systems neuroscience strategy is essential to selecting and evaluating effective treatments, and illustrate this with findings from clinical trials; and (iv) selectively review the interventional literature relevant to sleep and cognition, covering both pharmacological and noninvasive brain stimulation approaches. We conclude that coordinated sleep oscillations are promising targets for improving cognition in schizophrenia and that effective therapies will need to preserve or enhance sleep oscillatory dynamics and restore function at the network level.
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Affiliation(s)
- Dara S Manoach
- Department of Psychiatry Massachusetts General Hospital, Harvard Medical School, Boston, MA 02215, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA.
| | - Dimitrios Mylonas
- Department of Psychiatry Massachusetts General Hospital, Harvard Medical School, Boston, MA 02215, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
| | - Bryan Baxter
- Department of Psychiatry Massachusetts General Hospital, Harvard Medical School, Boston, MA 02215, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital and Harvard Medical School, Charlestown, MA 02129, USA
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30
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Neurostimulation techniques to enhance sleep and improve cognition in aging. Neurobiol Dis 2020; 141:104865. [DOI: 10.1016/j.nbd.2020.104865] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 03/16/2020] [Accepted: 04/02/2020] [Indexed: 01/09/2023] Open
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Fröhlich F, Lustenberger C. Neuromodulation of sleep rhythms in schizophrenia: Towards the rational design of non-invasive brain stimulation. Schizophr Res 2020; 221:71-80. [PMID: 32354662 PMCID: PMC7316586 DOI: 10.1016/j.schres.2020.04.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Revised: 04/01/2020] [Accepted: 04/03/2020] [Indexed: 02/01/2023]
Abstract
Brain function critically depends on oscillatory synchronization of neuronal populations both during wake and sleep. Originally, neural oscillations have been discounted as an epiphenomenon. More recently, specific deficits in the structure of brain oscillations have been linked to psychiatric diseases. For example, schizophrenia is hallmarked by abnormalities in different brain oscillations. Key sleep rhythms during NEM sleep such as sleep spindles, which are implicated in memory consolidation and are related to cognitive functions, are strongly diminished in these patients compared to healthy controls. To date, it remains unclear whether these reductions in sleep oscillations are causal for the functional impairments observed in schizophrenia. The application of non-invasive brain stimulation permits the causal examination of brain network dynamics and will help to establish the causal association of sleep oscillations and symptoms of schizophrenia. To accomplish this, stimulation paradigms that selectively engage specific network targets such as sleep spindles or slow waves are needed. We propose that the successful development and application of these non-invasive brain stimulation approaches will require rational design that takes network dynamics and neuroanatomical information into account. The purpose of this article is to prepare the grounds for the next steps towards such rational design of non-invasive stimulation, with a special focus on electrical and auditory stimulation. First, we briefly summarize the deficits in network dynamics during sleep in schizophrenia. Then, we discuss today's and tomorrow's non-invasive brain stimulation modalities to engage these network targets.
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Affiliation(s)
- Flavio Fröhlich
- Department of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Carolina Center for Neurostimulation, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Neuroscience Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Neurology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA; Department of Biomedical Engineering, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA.
| | - Caroline Lustenberger
- Neural Control of Movement Lab, Institute of Movement Sciences and Sport, Department of Health Sciences and Technology, ETH Zurich, 8092 Zurich, Switzerland.
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Salfi F, D'Atri A, Tempesta D, De Gennaro L, Ferrara M. Boosting Slow Oscillations during Sleep to Improve Memory Function in Elderly People: A Review of the Literature. Brain Sci 2020; 10:E300. [PMID: 32429181 PMCID: PMC7287854 DOI: 10.3390/brainsci10050300] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 05/11/2020] [Accepted: 05/13/2020] [Indexed: 02/05/2023] Open
Abstract
Sleep represents a crucial time window for the consolidation of memory traces. In this view, some brain rhythms play a pivotal role, first of all the sleep slow waves. In particular, the neocortical slow oscillations (SOs), in coordination with the hippocampal ripples and the thalamocortical spindles, support the long-term storage of the declarative memories. The aging brain is characterized by a disruption of this complex system with outcomes on the related cognitive functions. In recent years, the advancement of the comprehension of the sleep-dependent memory consolidation mechanisms has encouraged the development of techniques of SO enhancement during sleep to induce cognitive benefits. In this review, we focused on the studies reporting on the application of acoustic or electric stimulation procedures in order to improve sleep-dependent memory consolidation in older subjects. Although the current literature is limited and presents inconsistencies, there is promising evidence supporting the perspective to non-invasively manipulate the sleeping brain electrophysiology to improve cognition in the elderly, also shedding light on the mechanisms underlying the sleep-memory relations during healthy and pathological aging.
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Affiliation(s)
- Federico Salfi
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100 L'Aquila, Italy
| | - Aurora D'Atri
- Department of Psychology, Sapienza University of Rome, 00185 Rome, Italy
| | - Daniela Tempesta
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100 L'Aquila, Italy
| | - Luigi De Gennaro
- Department of Psychology, Sapienza University of Rome, 00185 Rome, Italy
| | - Michele Ferrara
- Department of Biotechnological and Applied Clinical Sciences, University of L'Aquila, 67100 L'Aquila, Italy
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Abstract
Given the critical role of sleep, particularly sleep slow oscillations, sleep spindles, and hippocampal sharp wave ripples, in memory consolidation, sleep enhancement represents a key opportunity to improve cognitive performance. Techniques such as transcranial electrical and magnetic stimulation and acoustic stimulation can enhance slow oscillations and sleep spindles and potentially improve memory. Targeted memory reactivation in sleep may enhance or stabilize memory consolidation. Each technique has technical considerations that may limit its broader clinical application. Therefore, neurostimulation to enhance sleep quality, in particular sleep slow oscillations, has the potential for improving sleep-related memory consolidation in healthy and clinical populations.
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Affiliation(s)
- Roneil G Malkani
- Division of Sleep Medicine, Department of Neurology, Center for Circadian and Sleep Medicine, Northwestern University Feinberg School of Medicine. 710 North Lake Shore Drive, Suite 525, Chicago, IL 60611, USA.
| | - Phyllis C Zee
- Division of Sleep Medicine, Department of Neurology, Center for Circadian and Sleep Medicine, Northwestern University Feinberg School of Medicine. 710 North Lake Shore Drive, Suite 520, Chicago, IL 60611, USA
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Marshall L, Cross N, Binder S, Dang-Vu TT. Brain Rhythms During Sleep and Memory Consolidation: Neurobiological Insights. Physiology (Bethesda) 2020; 35:4-15. [DOI: 10.1152/physiol.00004.2019] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Sleep can benefit memory consolidation. The characterization of brain regions underlying memory consolidation during sleep, as well as their temporal interplay, reflected by specific patterns of brain electric activity, is surfacing. Here, we provide an overview of recent concepts and results on the mechanisms of sleep-related memory consolidation. The latest studies strongly impacting future directions of research in this field are highlighted.
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Affiliation(s)
- Lisa Marshall
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Luebeck, Luebeck, Germany
- Center for Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Nathan Cross
- Perform Center, Center for Studies in Behavioral Neurobiology, and Department of Health, Kinesiology and Applied Physiology, Concordia University, Montreal, Quebec, Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal, CIUSSS Centre-Sud-de-l’Ile-de-Montréal, Montreal, Quebec, Canada
| | - Sonja Binder
- Institute for Experimental and Clinical Pharmacology and Toxicology, University of Luebeck, Luebeck, Germany
- Center for Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Thien Thanh Dang-Vu
- Perform Center, Center for Studies in Behavioral Neurobiology, and Department of Health, Kinesiology and Applied Physiology, Concordia University, Montreal, Quebec, Canada
- Centre de Recherche de l’Institut Universitaire de Gériatrie de Montréal, CIUSSS Centre-Sud-de-l’Ile-de-Montréal, Montreal, Quebec, Canada
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Distinct Montages of Slow Oscillatory Transcranial Direct Current Stimulation (so-tDCS) Constitute Different Mechanisms during Quiet Wakefulness. Brain Sci 2019; 9:brainsci9110324. [PMID: 31739576 PMCID: PMC6896026 DOI: 10.3390/brainsci9110324] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 11/06/2019] [Accepted: 11/11/2019] [Indexed: 12/13/2022] Open
Abstract
Slow oscillatory- (so-) tDCS has been applied in many sleep studies aimed to modulate brain rhythms of slow wave sleep and memory consolidation. Yet, so-tDCS may also modify coupled oscillatory networks. Efficacy of weak electric brain stimulation is however variable and dependent upon the brain state at the time of stimulation (subject and/or task-related) as well as on stimulation parameters (e.g., electrode placement and applied current. Anodal so-tDCS was applied during wakefulness with eyes-closed to examine efficacy when deviating from the dominant brain rhythm. Additionally, montages of different electrodes size and applied current strength were used. During a period of quiet wakefulness bilateral frontolateral stimulation (F3, F4; return electrodes at ipsilateral mastoids) was applied to two groups: ‘Group small’ (n = 16, f:8; small electrodes: 0.50 cm2; maximal current per electrode pair: 0.26 mA) and ‘Group Large’ (n = 16, f:8; 35 cm2; 0.35 mA). Anodal so-tDCS (0.75 Hz) was applied in five blocks of 5 min epochs with 1 min stimulation-free epochs between the blocks. A finger sequence tapping task (FSTT) was used to induce comparable cortical activity across sessions and subject groups. So-tDCS resulted in a suppression of alpha power over the parietal cortex. Interestingly, in Group Small alpha suppression occurred over the standard band (8–12 Hz), whereas for Group Large power of individual alpha frequency was suppressed. Group Small also revealed a decrease in FSTT performance at retest after stimulation. It is essential to include concordant measures of behavioral and brain activity to help understand variability and poor reproducibility in oscillatory-tDCS studies.
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Bueno-Lopez A, Eggert T, Dorn H, Danker-Hopfe H. Slow oscillatory transcranial direct current stimulation (so-tDCS) during slow wave sleep has no effects on declarative memory in healthy young subjects. Brain Stimul 2019; 12:948-958. [DOI: 10.1016/j.brs.2019.02.012] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 02/13/2019] [Accepted: 02/15/2019] [Indexed: 12/14/2022] Open
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Enhancing Memory Consolidation through Slow Oscillation and Spindle Synchronization. J Neurosci 2019; 37:11517-11519. [PMID: 29187611 DOI: 10.1523/jneurosci.2512-17.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 10/16/2017] [Indexed: 11/21/2022] Open
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Jones AP, Choe J, Bryant NB, Robinson CSH, Ketz NA, Skorheim SW, Combs A, Lamphere ML, Robert B, Gill HA, Heinrich MD, Howard MD, Clark VP, Pilly PK. Dose-Dependent Effects of Closed-Loop tACS Delivered During Slow-Wave Oscillations on Memory Consolidation. Front Neurosci 2018; 12:867. [PMID: 30538617 PMCID: PMC6277682 DOI: 10.3389/fnins.2018.00867] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 11/06/2018] [Indexed: 11/13/2022] Open
Abstract
Sleep is critically important to consolidate information learned throughout the day. Slow-wave sleep (SWS) serves to consolidate declarative memories, a process previously modulated with open-loop non-invasive electrical stimulation, though not always effectively. These failures to replicate could be explained by the fact that stimulation has only been performed in open-loop, as opposed to closed-loop where phase and frequency of the endogenous slow-wave oscillations (SWOs) are matched for optimal timing. The current study investigated the effects of closed-loop transcranial Alternating Current Stimulation (tACS) targeting SWOs during sleep on memory consolidation. 21 participants took part in a three-night, counterbalanced, randomized, single-blind, within-subjects study, investigating performance changes (correct rate and F1 score) on images in a target detection task over 24 h. During sleep, 1.5 mA closed-loop tACS was delivered in phase over electrodes at F3 and F4 and 180° out of phase over electrodes at bilateral mastoids at the frequency (range 0.5-1.2 Hz) and phase of ongoing SWOs for a duration of 5 cycles in each discrete event throughout the night. Data were analyzed in a repeated measures ANOVA framework, and results show that verum stimulation improved post-sleep performance specifically on generalized versions of images used in training at both morning and afternoon tests compared to sham, suggesting the facilitation of schematization of information, but not of rote, veridical recall. We also found a surprising inverted U-shaped dose effect of sleep tACS, which is interpreted in terms of tACS-induced faciliatory and subsequent refractory dynamics of SWO power in scalp EEG. This is the first study showing a selective modulation of long-term memory generalization using a novel closed-loop tACS approach, which holds great potential for both healthy and neuropsychiatric populations.
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Affiliation(s)
- Aaron P Jones
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
| | - Jaehoon Choe
- Center for Human-Machine Collaboration, Information and Systems Sciences Laboratory, HRL Laboratories, LLC, Malibu, CA, United States
| | - Natalie B Bryant
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
| | - Charles S H Robinson
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States.,The Mind Research Network, Albuquerque, NM, United States
| | - Nicholas A Ketz
- Center for Human-Machine Collaboration, Information and Systems Sciences Laboratory, HRL Laboratories, LLC, Malibu, CA, United States
| | - Steven W Skorheim
- Center for Human-Machine Collaboration, Information and Systems Sciences Laboratory, HRL Laboratories, LLC, Malibu, CA, United States
| | - Angela Combs
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
| | - Melanie L Lamphere
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
| | - Bradley Robert
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
| | - Hope A Gill
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
| | - Melissa D Heinrich
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States
| | - Michael D Howard
- Center for Human-Machine Collaboration, Information and Systems Sciences Laboratory, HRL Laboratories, LLC, Malibu, CA, United States
| | - Vincent P Clark
- Psychology Clinical Neuroscience Center, The University of New Mexico, Albuquerque, NM, United States.,Department of Psychology, The University of New Mexico, Albuquerque, NM, United States.,The Mind Research Network, Albuquerque, NM, United States.,Department of Neuroscience, University of New Mexico School of Medicine, Albuquerque, NM, United States
| | - Praveen K Pilly
- Center for Human-Machine Collaboration, Information and Systems Sciences Laboratory, HRL Laboratories, LLC, Malibu, CA, United States
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Cellini N, Mednick SC. Stimulating the sleeping brain: Current approaches to modulating memory-related sleep physiology. J Neurosci Methods 2018; 316:125-136. [PMID: 30452977 DOI: 10.1016/j.jneumeth.2018.11.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2018] [Revised: 10/25/2018] [Accepted: 11/14/2018] [Indexed: 10/27/2022]
Abstract
BACKGROUND One of the most audacious proposals throughout the history of psychology was the potential ability to learn while we sleep. The idea penetrated culture via sci-fi movies and inspired the invention of devices that claimed to teach foreign languages, facts, and even quit smoking by simply listening to audiocassettes or other devices during sleep. However, the promises from this endeavor didn't stand up to experimental scrutiny, and the dream was shunned from the scientific community. Despite the historic evidence that the sleeping brain cannot learn new complex information (i.e., words, images, facts), a new wave of current interventions are demonstrating that sleep can be manipulated to strengthen recent memories. NEW METHOD Several recent approaches have been developed that play with the sleeping brain in order to modify ongoing memory processing. Here, we provide an overview of the available techniques to non-invasively modulate memory-related sleep physiology, including sensory, vestibular and electrical stimulation, as well as pharmacological approaches. RESULTS N/A. COMPARISON WITH EXISTING METHODS N/A. CONCLUSIONS Although the results are encouraging, suggesting that in general the sleeping brain may be optimized for better memory performance, the road to bring these techniques in free-living conditions is paved with unanswered questions and technical challenges that need to be carefully addressed.
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Affiliation(s)
- Nicola Cellini
- Department of General Psychology, University of Padova, Padova, Italy.
| | - Sara C Mednick
- Department of Cognitive Sciences, University of California, Irvine, United States
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Scullin MK, Gao C. Dynamic Contributions of Slow Wave Sleep and REM Sleep to Cognitive Longevity. CURRENT SLEEP MEDICINE REPORTS 2018; 4:284-293. [PMID: 31737466 DOI: 10.1007/s40675-018-0131-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Purpose of review The purpose of this paper was to address how sleep changes with aging, with the broader goal of informing how REM sleep and slow wave activity mechanisms interact to promote cognitive longevity. Recent findings We conducted novel analyses based on the National Sleep Research Resource database. Over approximately five years, middle-to-older aged adults, on average, showed dramatically worse sleep fragmentation, a steady decrease in slow wave sleep, and yet a small increase in REM sleep. Averaging across participants, however, masked a major theme: Individuals differ substantially in their longitudinal trajectories for specific components of sleep. We considered this individual variability in light of recent theoretical and empirical work that has shown disrupted sleep and decreased slow wave activity to impair frontal lobe restoration, glymphatic system functioning, and memory consolidation. Based on multiple recent longitudinal studies, we contend that preserved or enhanced REM sleep may compensate for otherwise disrupted sleep in advancing age. Summary The scientific community has often debated whether slow wave activity or REM sleep mechanisms are more important to cognitive aging. We propose that a more fruitful approach for future work will be to investigate how REM and slow wave processes dynamically interact to affect cognitive longevity.
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Affiliation(s)
- Michael K Scullin
- Department of Psychology and Neuroscience, Baylor University, Waco, TX
| | - Chenlu Gao
- Department of Psychology and Neuroscience, Baylor University, Waco, TX
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The Efficacy of Transcranial Current Stimulation Techniques to Modulate Resting-State EEG, to Affect Vigilance and to Promote Sleepiness. Brain Sci 2018; 8:brainsci8070137. [PMID: 30037023 PMCID: PMC6071002 DOI: 10.3390/brainsci8070137] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 07/09/2018] [Accepted: 07/17/2018] [Indexed: 02/05/2023] Open
Abstract
Transcranial Current Stimulations (tCSs) are non-invasive brain stimulation techniques which modulate cortical excitability and spontaneous brain activity by the application of weak electric currents through the scalp, in a safe, economic, and well-tolerated manner. The direction of the cortical effects mainly depend on the polarity and the waveform of the applied current. The aim of the present work is to provide a broad overview of recent studies in which tCS has been applied to modulate sleepiness, sleep, and vigilance, evaluating the efficacy of different stimulation techniques and protocols. In recent years, there has been renewed interest in these stimulations and their ability to affect arousal and sleep dynamics. Furthermore, we critically review works that, by means of stimulating sleep/vigilance patterns, in the sense of enhancing or disrupting them, intended to ameliorate several clinical conditions. The examined literature shows the efficacy of tCSs in modulating sleep and arousal pattern, likely acting on the top-down pathway of sleep regulation. Finally, we discuss the potential application in clinical settings of this neuromodulatory technique as a therapeutic tool for pathological conditions characterized by alterations in sleep and arousal domains and for sleep disorders per se.
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Koo PC, Mölle M, Marshall L. Efficacy of slow oscillatory‐transcranial direct current stimulation on
EEG
and memory – contribution of an inter‐individual factor. Eur J Neurosci 2018; 47:812-823. [DOI: 10.1111/ejn.13877] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2017] [Revised: 02/08/2018] [Accepted: 02/16/2018] [Indexed: 11/26/2022]
Affiliation(s)
- Ping Chai Koo
- Institute of Experimental and Clinical Pharmacology and Toxicology University of Lübeck Ratzeburger Allee 160, Bldg 66 23562 Lübeck Germany
- Center of Brain, Behavior and Metabolism University of Lübeck Lübeck Germany
- Department of Psychiatry and Psychotherapy Rostock University Medical Centre Rostock Germany
| | - Matthias Mölle
- Center of Brain, Behavior and Metabolism University of Lübeck Lübeck Germany
| | - Lisa Marshall
- Institute of Experimental and Clinical Pharmacology and Toxicology University of Lübeck Ratzeburger Allee 160, Bldg 66 23562 Lübeck Germany
- Center of Brain, Behavior and Metabolism University of Lübeck Lübeck Germany
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Promoting Sleep Oscillations and Their Functional Coupling by Transcranial Stimulation Enhances Memory Consolidation in Mild Cognitive Impairment. J Neurosci 2017. [PMID: 28637840 DOI: 10.1523/jneurosci.0260-17.2017] [Citation(s) in RCA: 148] [Impact Index Per Article: 21.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Alzheimer's disease (AD) not only involves loss of memory functions, but also prominent deterioration of sleep physiology, which is already evident at the stage of mild cognitive impairment (MCI). Cortical slow oscillations (SO; 0.5-1 Hz) and thalamocortical spindle activity (12-15 Hz) during sleep, and their temporal coordination, are considered critical for memory formation. We investigated the potential of slow oscillatory transcranial direct current stimulation (so-tDCS), applied during a daytime nap in a sleep-state-dependent manner, to modulate these activity patterns and sleep-related memory consolidation in nine male and seven female human patients with MCI. Stimulation significantly increased overall SO and spindle power, amplified spindle power during SO up-phases, and led to stronger synchronization between SO and spindle power fluctuations in EEG recordings. Moreover, visual declarative memory was improved by so-tDCS compared with sham stimulation and was associated with stronger synchronization. These findings indicate a well-tolerated therapeutic approach for disordered sleep physiology and memory deficits in MCI patients and advance our understanding of offline memory consolidation.SIGNIFICANCE STATEMENT In the light of increasing evidence that sleep disruption is crucially involved in the progression of Alzheimer's disease (AD), sleep appears as a promising treatment target in this pathology, particularly to counteract memory decline. This study demonstrates the potential of a noninvasive brain stimulation method during sleep in patients with mild cognitive impairment (MCI), a precursor of AD, and advances our understanding of its mechanism. We provide first time evidence that slow oscillatory transcranial stimulation amplifies the functional cross-frequency coupling between memory-relevant brain oscillations and improves visual memory consolidation in patients with MCI.
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Scullin MK, Fairley J, Decker MJ, Bliwise DL. The Effects of an Afternoon Nap on Episodic Memory in Young and Older Adults. Sleep 2017; 40:3059371. [PMID: 28329381 PMCID: PMC5445560 DOI: 10.1093/sleep/zsx035] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Study Objectives In young adults, napping is hypothesized to benefit episodic memory retention (eg, via consolidation). Whether this relationship is present in older adults has not been adequately tested but is an important question because older adults display marked changes in sleep and memory. Design Between-subjects design. Setting Sleep laboratory at Emory University School of Medicine. Participants Fifty healthy young adults (18-29) and 45 community-dwelling older adults (58-83). Intervention Participants were randomly assigned to a 90-minute nap opportunity or an equal interval of quiet wakefulness. Measurements and Results Participants underwent an item-wise directed forgetting learning procedure in which they studied words that were individually followed by the instruction to "remember" or "forget." Following a 90-minute retention interval filled with quiet wakefulness or a nap opportunity, they were asked to free recall and recognize those words. Young adults retained significantly more words following a nap interval than a quiet wakefulness interval on both free recall and recognition tests. There was modest evidence for greater nap-related retention of "remember" items relative to "forget" items for free recall but not recognition. Older adults' memory retention did not differ across nap and quiet wakefulness conditions, although they demonstrated greater fragmentation, lower N3, and lower rapid eye movement duration than the young adults. Conclusions In young adults, an afternoon nap benefits episodic memory retention, but such benefits decrease with advancing age.
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Affiliation(s)
- Michael K Scullin
- Department of Psychology and Neuroscience, Baylor University, Waco, TX
- Department of Neurology, Emory University School of Medicine, Atlanta, GA
| | - Jacqueline Fairley
- Department of Neurology, Emory University School of Medicine, Atlanta, GA
| | - Michael J Decker
- Francis Payne Bolton School of Nursing, Case Western Reserve University, Cleveland, OH
| | - Donald L Bliwise
- Department of Neurology, Emory University School of Medicine, Atlanta, GA
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Mander BA, Winer JR, Walker MP. Sleep and Human Aging. Neuron 2017; 94:19-36. [PMID: 28384471 PMCID: PMC5810920 DOI: 10.1016/j.neuron.2017.02.004] [Citation(s) in RCA: 604] [Impact Index Per Article: 86.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 02/02/2017] [Accepted: 02/03/2017] [Indexed: 12/13/2022]
Abstract
Older adults do not sleep as well as younger adults. Why? What alterations in sleep quantity and quality occur as we age, and are there functional consequences? What are the underlying neural mechanisms that explain age-related sleep disruption? This review tackles these questions. First, we describe canonical changes in human sleep quantity and quality in cognitively normal older adults. Second, we explore the underlying neurobiological mechanisms that may account for these human sleep alterations. Third, we consider the functional consequences of age-related sleep disruption, focusing on memory impairment as an exemplar. We conclude with a discussion of a still-debated question: do older adults simply need less sleep, or rather, are they unable to generate the sleep that they still need?
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Affiliation(s)
- Bryce A Mander
- Sleep and Neuroimaging Laboratory, Department of Psychology, University of California, Berkeley, Berkeley, CA 94720-1650, USA
| | - Joseph R Winer
- Sleep and Neuroimaging Laboratory, Department of Psychology, University of California, Berkeley, Berkeley, CA 94720-1650, USA
| | - Matthew P Walker
- Sleep and Neuroimaging Laboratory, Department of Psychology, University of California, Berkeley, Berkeley, CA 94720-1650, USA; Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA 94720-1650, USA.
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