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Isotalus HK, Carr WJ, Blackman J, Averill GG, Radtke O, Selwood J, Williams R, Ford E, McCullagh L, McErlane J, O’Donnell C, Durant C, Bartsch U, Jones MW, Muñoz-Neira C, Wearn AR, Grogan JP, Coulthard EJ. L-DOPA increases slow-wave sleep duration and selectively modulates memory persistence in older adults. Front Behav Neurosci 2023; 17:1096720. [PMID: 37091594 PMCID: PMC10113484 DOI: 10.3389/fnbeh.2023.1096720] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2022] [Accepted: 03/20/2023] [Indexed: 04/25/2023] Open
Abstract
Introduction Millions of people worldwide take medications such as L-DOPA that increase dopamine to treat Parkinson's disease. Yet, we do not fully understand how L-DOPA affects sleep and memory. Our earlier research in Parkinson's disease revealed that the timing of L-DOPA relative to sleep affects dopamine's impact on long-term memory. Dopamine projections between the midbrain and hippocampus potentially support memory processes during slow wave sleep. In this study, we aimed to test the hypothesis that L-DOPA enhances memory consolidation by modulating NREM sleep. Methods We conducted a double-blind, randomised, placebo-controlled crossover trial with healthy older adults (65-79 years, n = 35). Participants first learned a word list and were then administered long-acting L-DOPA (or placebo) before a full night of sleep. Before sleeping, a proportion of the words were re-exposed using a recognition test to strengthen memory. L-DOPA was active during sleep and the practice-recognition test, but not during initial learning. Results The single dose of L-DOPA increased total slow-wave sleep duration by approximately 11% compared to placebo, while also increasing spindle amplitudes around slow oscillation peaks and around 1-4 Hz NREM spectral power. However, behaviourally, L-DOPA worsened memory of words presented only once compared to re-exposed words. The coupling of spindles to slow oscillation peaks correlated with these differential effects on weaker and stronger memories. To gauge whether L-DOPA affects encoding or retrieval of information in addition to consolidation, we conducted a second experiment targeting L-DOPA only to initial encoding or retrieval and found no behavioural effects. Discussion Our results demonstrate that L-DOPA augments slow wave sleep in elderly, perhaps tuning coordinated network activity and impacting the selection of information for long-term storage. The pharmaceutical modification of slow-wave sleep and long-term memory may have clinical implications. Clinical trial registration Eudract number: 2015-002027-26; https://doi.org/10.1186/ISRCTN90897064, ISRCTN90897064.
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Affiliation(s)
- Hanna K. Isotalus
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Digital Health, Faculty of Engineering, University of Bristol, Bristol, United Kingdom
- *Correspondence: Hanna K. Isotalus,
| | - Will J. Carr
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Jonathan Blackman
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Southmead Hospital, North Bristol NHS Trust, Bristol, United Kingdom
| | - George G. Averill
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Oliver Radtke
- Department of Neurosurgery, Heinrich-Heine-University Clinic, Düsseldorf, Germany
| | - James Selwood
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Southmead Hospital, North Bristol NHS Trust, Bristol, United Kingdom
| | - Rachel Williams
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Elizabeth Ford
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Liz McCullagh
- Production Pharmacy, Bristol Royal Infirmary, University Hospitals Bristol and Weston NHS Trust, Bristol, United Kingdom
| | - James McErlane
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Cian O’Donnell
- School of Computer Science, Electrical and Electronic Engineering, and Engineering Mathematics, University of Bristol, Bristol, United Kingdom
| | - Claire Durant
- Experimental Psychology, University of Bristol, Bristol, United Kingdom
| | - Ullrich Bartsch
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Matt W. Jones
- School of Physiology, Pharmacology and Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Carlos Muñoz-Neira
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Alfie R. Wearn
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - John P. Grogan
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, United Kingdom
- School of Psychology, Trinity College Dublin, Dublin, Ireland
| | - Elizabeth J. Coulthard
- Clinical Neurosciences, Translational Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Southmead Hospital, North Bristol NHS Trust, Bristol, United Kingdom
- Elizabeth J. Coulthard,
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Wearn AR, Nurdal V, Saunders-Jennings E, Knight MJ, Madan CR, Fallon SJ, Isotalus HK, Kauppinen RA, Coulthard EJ. T2 heterogeneity as an in vivo marker of microstructural integrity in medial temporal lobe subfields in ageing and mild cognitive impairment. Neuroimage 2021; 238:118214. [PMID: 34116150 PMCID: PMC8350145 DOI: 10.1016/j.neuroimage.2021.118214] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 05/19/2021] [Accepted: 05/25/2021] [Indexed: 11/19/2022] Open
Abstract
A better understanding of early brain changes that precede loss of independence in diseases like Alzheimer's disease (AD) is critical for development of disease-modifying therapies. Quantitative MRI, such as T2 relaxometry, can identify microstructural changes relevant to early stages of pathology. Recent evidence suggests heterogeneity of T2 may be a more informative MRI measure of early pathology than absolute T2. Here we test whether T2 markers of brain integrity precede the volume changes we know are present in established AD and whether such changes are most marked in medial temporal lobe (MTL) subfields known to be most affected early in AD. We show that T2 heterogeneity was greater in people with mild cognitive impairment (MCI; n = 49) compared to healthy older controls (n = 99) in all MTL subfields, but this increase was greatest in MTL cortices, and smallest in dentate gyrus. This reflects the spatio-temporal progression of neurodegeneration in AD. T2 heterogeneity in CA1-3 and entorhinal cortex and volume of entorhinal cortex showed some ability to predict cognitive decline, where absolute T2 could not, however further studies are required to verify this result. Increases in T2 heterogeneity in MTL cortices may reflect localised pathological change and may present as one of the earliest detectible brain changes prior to atrophy. Finally, we describe a mechanism by which memory, as measured by accuracy and reaction time on a paired associate learning task, deteriorates with age. Age-related memory deficits were explained in part by lower subfield volumes, which in turn were directly associated with greater T2 heterogeneity. We propose that tissue with high T2 heterogeneity represents extant tissue at risk of permanent damage but with the potential for therapeutic rescue. This has implications for early detection of neurodegenerative diseases and the study of brain-behaviour relationships.
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Affiliation(s)
- Alfie R Wearn
- Bristol Medical School, University of Bristol, Institute of Clinical Neurosciences, Learning & Research Building at Southmead Hospital, Bristol BS10 5NB, UK.
| | - Volkan Nurdal
- Bristol Medical School, University of Bristol, Institute of Clinical Neurosciences, Learning & Research Building at Southmead Hospital, Bristol BS10 5NB, UK
| | - Esther Saunders-Jennings
- Bristol Medical School, University of Bristol, Institute of Clinical Neurosciences, Learning & Research Building at Southmead Hospital, Bristol BS10 5NB, UK
| | - Michael J Knight
- School of Psychological Science, University of Bristol, Bristol, UK
| | | | - Sean-James Fallon
- National Institute for Health Research Bristol Biomedical Research Centre, University Hospitals Bristol, NHS Foundation Trust and University of Bristol, Bristol, UK
| | - Hanna K Isotalus
- Bristol Medical School, University of Bristol, Institute of Clinical Neurosciences, Learning & Research Building at Southmead Hospital, Bristol BS10 5NB, UK
| | | | - Elizabeth J Coulthard
- Bristol Medical School, University of Bristol, Institute of Clinical Neurosciences, Learning & Research Building at Southmead Hospital, Bristol BS10 5NB, UK; Clinical Neurosciences, North Bristol NHS Trust, Bristol, UK
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Wearn AR, Saunders-Jennings E, Nurdal V, Hadley E, Knight MJ, Newson M, Kauppinen RA, Coulthard EJ. Accelerated long-term forgetting in healthy older adults predicts cognitive decline over 1 year. Alzheimers Res Ther 2020; 12:119. [PMID: 32988418 PMCID: PMC7523317 DOI: 10.1186/s13195-020-00693-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Accepted: 09/16/2020] [Indexed: 01/17/2023]
Abstract
Background Here, we address a pivotal factor in Alzheimer’s prevention—identifying those at risk early, when dementia can still be avoided. Recent research highlights an accelerated forgetting phenotype as a risk factor for Alzheimer’s disease. We hypothesized that delayed recall over 4 weeks would predict cognitive decline over 1 year better than 30-min delayed recall, the current gold standard for detecting episodic memory problems which could be an early clinical manifestation of incipient Alzheimer’s disease. We also expected hippocampal subfield volumes to improve predictive accuracy. Methods Forty-six cognitively healthy older people (mean age 70.7 ± 7.97, 21/46 female), recruited from databases such as Join Dementia Research, or a local database of volunteers, performed 3 memory tasks on which delayed recall was tested after 30 min and 4 weeks, as well as Addenbrooke’s Cognitive Examination III (ACE-III) and CANTAB Paired Associates Learning. Medial temporal lobe subregion volumes were automatically measured using high-resolution 3T MRI. The ACE-III was repeated after 12 months to assess the change in cognitive ability. We used univariate linear regressions and ROC curves to assess the ability of tests of delayed recall to predict cognitive decline on ACE-III over the 12 months. Results Fifteen of the 46 participants declined over the year (≥ 3 points lost on ACE-III). Four-week verbal memory predicted cognitive decline in healthy older people better than clinical gold standard memory tests and hippocampal MRI. The best single-test predictor of cognitive decline was the 4-week delayed recall on the world list (R2 = .123, p = .018, β = .418). Combined with hippocampal subfield volumetry, 4-week verbal recall identifies those at risk of cognitive decline with 93% sensitivity and 86% specificity (AUC = .918, p < .0001). Conclusions We show that a test of accelerated long-term forgetting over 4 weeks can predict cognitive decline in healthy older people where traditional tests of delayed recall cannot. Accelerated long-term forgetting is a sensitive, easy-to-test predictor of cognitive decline in healthy older people. Used alone or with hippocampal MRI, accelerated forgetting probes functionally relevant Alzheimer’s-related change. Accelerated forgetting will identify early-stage impairment, helping to target more invasive and expensive molecular biomarker testing.
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Affiliation(s)
- Alfie R Wearn
- Bristol Medical School, University of Bristol, Bristol, UK. .,Institute of Clinical Neurosciences, North Bristol NHS Trust, Bristol, UK.
| | | | - Volkan Nurdal
- Bristol Medical School, University of Bristol, Bristol, UK.,Department of Psychology, University of Bath, Bath, UK
| | - Emma Hadley
- Bristol Medical School, University of Bristol, Bristol, UK
| | - Michael J Knight
- School of Psychological Science, University of Bristol, Bristol, UK
| | - Margaret Newson
- Institute of Clinical Neurosciences, North Bristol NHS Trust, Bristol, UK.,School of Psychological Science, University of Bristol, Bristol, UK
| | | | - Elizabeth J Coulthard
- Bristol Medical School, University of Bristol, Bristol, UK.,Institute of Clinical Neurosciences, North Bristol NHS Trust, Bristol, UK
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Wearn AR, Nurdal V, Saunders-Jennings E, Knight MJ, Isotalus HK, Dillon S, Tsivos D, Kauppinen RA, Coulthard EJ. T2 heterogeneity: a novel marker of microstructural integrity associated with cognitive decline in people with mild cognitive impairment. Alzheimers Res Ther 2020; 12:105. [PMID: 32912337 PMCID: PMC7488446 DOI: 10.1186/s13195-020-00672-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/25/2020] [Indexed: 02/08/2023]
Abstract
BACKGROUND Early Alzheimer's disease (AD) diagnosis is vital for development of disease-modifying therapies. Prior to significant brain tissue atrophy, several microstructural changes take place as a result of Alzheimer's pathology. These include deposition of amyloid, tau and iron, as well as altered water homeostasis in tissue and some cell death. T2 relaxation time, a quantitative MRI measure, is sensitive to these changes and may be a useful non-invasive, early marker of tissue integrity which could predict conversion to dementia. We propose that different microstructural changes affect T2 in opposing ways, such that average 'midpoint' measures of T2 are less sensitive than measuring distribution width (heterogeneity). T2 heterogeneity in the brain may present a sensitive early marker of AD pathology. METHODS In this cohort study, we tested 97 healthy older controls, 49 people with mild cognitive impairment (MCI) and 10 with a clinical diagnosis of AD. All participants underwent structural MRI including a multi-echo sequence for quantitative T2 assessment. Cognitive change over 1 year was assessed in 20 participants with MCI. T2 distributions were modelled in the hippocampus and thalamus using log-logistic distribution giving measures of log-median value (midpoint; T2μ) and distribution width (heterogeneity; T2σ). RESULTS We show an increase in T2 heterogeneity (T2σ; p < .0001) in MCI compared to healthy controls, which was not seen with midpoint (T2μ; p = .149) in the hippocampus and thalamus. Hippocampal T2 heterogeneity predicted cognitive decline over 1 year in MCI participants (p = .018), but midpoint (p = .132) and volume (p = .315) did not. Age affects T2, but the effects described here are significant even after correcting for age. CONCLUSIONS We show that T2 heterogeneity can identify subtle changes in microstructural integrity of brain tissue in MCI and predict cognitive decline over a year. We describe a new model that considers the competing effects of factors that both increase and decrease T2. These two opposing forces suggest that previous conclusions based on T2 midpoint may have obscured the true potential of T2 as a marker of subtle neuropathology. We propose that T2 heterogeneity reflects microstructural integrity with potential to be a widely used early biomarker of conditions such as AD.
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Affiliation(s)
- Alfie R Wearn
- Bristol Medical School, University of Bristol, Bristol, UK.
- Institute of Clinical Neurosciences, North Bristol NHS Trust, Bristol, UK.
| | - Volkan Nurdal
- Bristol Medical School, University of Bristol, Bristol, UK
| | | | - Michael J Knight
- School of Psychological Science, University of Bristol, Bristol, UK
| | | | - Serena Dillon
- Bristol Medical School, University of Bristol, Bristol, UK
| | - Demitra Tsivos
- Bristol Medical School, University of Bristol, Bristol, UK
| | | | - Elizabeth J Coulthard
- Bristol Medical School, University of Bristol, Bristol, UK
- Institute of Clinical Neurosciences, North Bristol NHS Trust, Bristol, UK
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