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Kim AJ, Senior J, Chu S, Mather M. Aging impairs reactive attentional control but not proactive distractor inhibition. J Exp Psychol Gen 2024; 153:1938-1959. [PMID: 38780565 PMCID: PMC11250690 DOI: 10.1037/xge0001602] [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] [Indexed: 05/25/2024]
Abstract
Older adults tend to be more prone to distraction compared with young adults, and this age-related deficit has been attributed to a deficiency in inhibitory processing. However, recent findings challenge the notion that aging leads to global impairments in inhibition. To reconcile these mixed findings, we investigated how aging modulates multiple mechanisms of attentional control by tracking the timing and direction of eye movements. When engaged in feature-search mode and proactive distractor suppression, older adults made fewer first fixations to the target but inhibited the task-irrelevant salient distractor as effectively as did young adults. However, when engaged in singleton-search mode and required to reactively disengage from the distractor, older adults made significantly more first saccades toward the task-irrelevant salient distractor and showed increased fixation times in orienting to the target, longer dwell times on incorrect saccades, and increased saccadic reaction times compared with young adults. Our findings reveal that aging differently impairs attentional control depending on whether visual search requires proactive distractor suppression or reactive distractor disengagement. Furthermore, our oculomotor measures reveal both age-related deficits and age equivalence in various mechanisms of attention, including goal-directed orienting, selection history, disengagement, and distractor inhibition. These findings help explain why conclusions of age-related declines or age equivalence in mechanisms of attentional control are task specific and reveal that older adults do not exhibit global impairments in mechanisms of inhibition. (PsycInfo Database Record (c) 2024 APA, all rights reserved).
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Affiliation(s)
- Andy Jeesu Kim
- School of Gerontology, University of Southern California
| | - Joshua Senior
- School of Gerontology, University of Southern California
| | - Sonali Chu
- School of Gerontology, University of Southern California
| | - Mara Mather
- School of Gerontology, University of Southern California
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2
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Fink L, Simola J, Tavano A, Lange E, Wallot S, Laeng B. From pre-processing to advanced dynamic modeling of pupil data. Behav Res Methods 2024; 56:1376-1412. [PMID: 37351785 PMCID: PMC10991010 DOI: 10.3758/s13428-023-02098-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/20/2023] [Indexed: 06/24/2023]
Abstract
The pupil of the eye provides a rich source of information for cognitive scientists, as it can index a variety of bodily states (e.g., arousal, fatigue) and cognitive processes (e.g., attention, decision-making). As pupillometry becomes a more accessible and popular methodology, researchers have proposed a variety of techniques for analyzing pupil data. Here, we focus on time series-based, signal-to-signal approaches that enable one to relate dynamic changes in pupil size over time with dynamic changes in a stimulus time series, continuous behavioral outcome measures, or other participants' pupil traces. We first introduce pupillometry, its neural underpinnings, and the relation between pupil measurements and other oculomotor behaviors (e.g., blinks, saccades), to stress the importance of understanding what is being measured and what can be inferred from changes in pupillary activity. Next, we discuss possible pre-processing steps, and the contexts in which they may be necessary. Finally, we turn to signal-to-signal analytic techniques, including regression-based approaches, dynamic time-warping, phase clustering, detrended fluctuation analysis, and recurrence quantification analysis. Assumptions of these techniques, and examples of the scientific questions each can address, are outlined, with references to key papers and software packages. Additionally, we provide a detailed code tutorial that steps through the key examples and figures in this paper. Ultimately, we contend that the insights gained from pupillometry are constrained by the analysis techniques used, and that signal-to-signal approaches offer a means to generate novel scientific insights by taking into account understudied spectro-temporal relationships between the pupil signal and other signals of interest.
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Affiliation(s)
- Lauren Fink
- Department of Music, Max Planck Institute for Empirical Aesthetics, Grüneburgweg 14, 60322, Frankfurt am Main, Germany.
- Department of Psychology, Neuroscience & Behavior, McMaster University, 1280 Main St. West, Hamilton, Ontario, L8S 4L8, Canada.
| | - Jaana Simola
- Helsinki Collegium for Advanced Studies, University of Helsinki, Helsinki, Finland
- Department of Education, University of Helsinki, Helsinki, Finland
| | - Alessandro Tavano
- Department of Cognitive Neuropsychology, Max Planck Institute for Empirical Aesthetics, Frankfurt am Main, Germany
| | - Elke Lange
- Department of Music, Max Planck Institute for Empirical Aesthetics, Grüneburgweg 14, 60322, Frankfurt am Main, Germany
| | - Sebastian Wallot
- Department of Literature, Max Planck Institute for Empirical Aesthetics, Frankfurt am Main, Germany
- Institute for Sustainability Education and Psychologyy, Leuphana University, Lüneburg, Germany
| | - Bruno Laeng
- Department of Psychology, University of Oslo, Oslo, Norway
- RITMO Centre for Interdisciplinary studies in Rhythm, Time, and Motion, University of Oslo, Oslo, Norway
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3
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Donato L, Mordà D, Scimone C, Alibrandi S, D’Angelo R, Sidoti A. Bridging Retinal and Cerebral Neurodegeneration: A Focus on Crosslinks between Alzheimer-Perusini's Disease and Retinal Dystrophies. Biomedicines 2023; 11:3258. [PMID: 38137479 PMCID: PMC10741418 DOI: 10.3390/biomedicines11123258] [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: 11/01/2023] [Revised: 12/02/2023] [Accepted: 12/07/2023] [Indexed: 12/24/2023] Open
Abstract
In the early stages of Alzheimer-Perusini's disease (AD), individuals often experience vision-related issues such as color vision impairment, reduced contrast sensitivity, and visual acuity problems. As the disease progresses, there is a connection with glaucoma and age-related macular degeneration (AMD) leading to retinal cell death. The retina's involvement suggests a link with the hippocampus, where most AD forms start. A thinning of the retinal nerve fiber layer (RNFL) due to the loss of retinal ganglion cells (RGCs) is seen as a potential AD diagnostic marker using electroretinography (ERG) and optical coherence tomography (OCT). Amyloid beta fragments (Aβ), found in the eye's vitreous and aqueous humor, are also present in the cerebrospinal fluid (CSF) and accumulate in the retina. Aβ is known to cause tau hyperphosphorylation, leading to its buildup in various retinal layers. However, diseases like AD are now seen as mixed proteinopathies, with deposits of the prion protein (PrP) and α-synuclein found in affected brains and retinas. Glial cells, especially microglial cells, play a crucial role in these diseases, maintaining immunoproteostasis. Studies have shown similarities between retinal and brain microglia in terms of transcription factor expression and morphotypes. All these findings constitute a good start to achieving better comprehension of neurodegeneration in both the eye and the brain. New insights will be able to bring the scientific community closer to specific disease-modifying therapies.
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Affiliation(s)
- Luigi Donato
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
- Department of Biomolecular Strategies, Genetics, Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology (I.E.ME.S.T.), 90139 Palermo, Italy;
| | - Domenico Mordà
- Department of Biomolecular Strategies, Genetics, Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology (I.E.ME.S.T.), 90139 Palermo, Italy;
- Department of Veterinary Sciences, University of Messina, 98122 Messina, Italy
| | - Concetta Scimone
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
- Department of Biomolecular Strategies, Genetics, Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology (I.E.ME.S.T.), 90139 Palermo, Italy;
| | - Simona Alibrandi
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
- Department of Biomolecular Strategies, Genetics, Cutting-Edge Therapies, Euro-Mediterranean Institute of Science and Technology (I.E.ME.S.T.), 90139 Palermo, Italy;
| | - Rosalia D’Angelo
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
| | - Antonina Sidoti
- Department of Biomedical and Dental Sciences and Morphofunctional Imaging, Division of Medical Biotechnologies and Preventive Medicine, University of Messina, 98122 Messina, Italy; (L.D.); (C.S.); (R.D.); (A.S.)
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4
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Riley E, Cicero N, Swallow K, De Rosa E, Anderson A. Locus coeruleus neuromelanin accumulation and dissipation across the lifespan. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.17.562814. [PMID: 37905002 PMCID: PMC10614878 DOI: 10.1101/2023.10.17.562814] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
The pigment neuromelanin, produced in the locus coeruleus (LC) as a byproduct of catecholamine synthesis, gives the "blue spot" its name, and both identifies LC neurons and is thought to play an important yet complex role in normal and pathological aging. Using neuromelanin-sensitive T1-weighted turbo spin echo MRI scans we characterized volume and neuromelanin signal intensity in the LC of 96 participants between the ages of 19 and 86. Although LC volume did not change significantly throughout the lifespan, LC neuromelanin signal intensity increased from early adulthood, peaked around age 60 and precipitously declined thereafter. Neuromelanin intensity was greater in the caudal relative to rostral extent and in women relative to men. With regard to function, rostral LC neuromelanin intensity was associated with fluid cognition in older adults (60+) only in those above the 50th percentile of cognitive ability for age. The gradual accumulation of LC neuromelanin across the lifespan, its sudden dissipation in later life, and relation to preserved cognitive function, is consistent with its complex role in normal and pathological aging.
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Affiliation(s)
| | | | | | - Eve De Rosa
- Department of Psychology, Cornell University
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Barry C, Wang E. Racially fair pupillometry measurements for RGB smartphone cameras using the far red spectrum. Sci Rep 2023; 13:13841. [PMID: 37620445 PMCID: PMC10449795 DOI: 10.1038/s41598-023-40796-0] [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: 06/16/2023] [Accepted: 08/16/2023] [Indexed: 08/26/2023] Open
Abstract
Pupillometry is a measurement of pupil dilation commonly performed as part of neurological assessments. Prior work have demonstrated the potential for pupillometry in screening or diagnosing a number of neurological disorders including Alzheimer's Disease, Schizophrenia, and Traumatic Brain Injury. Unfortunately, the expense and inaccessibility of specialized pupilometers that image in the near infrared spectrum limit the measurement to high resource clinics or institutions. Ideally, this measurement could be available via ubiquitous devices like smartphones or tablets with integrated visible spectrum imaging systems. In the visible spectrum of RGB cameras, the melanin in the iris absorbs light such that it is difficult to distinguish the pupil aperature that appears black. In this paper, we propose a novel pupillometry technique to enable smartphone RGB cameras to effectively differentiate the pupil from the iris. The proposed system utilizes a 630 nm long-pass filter to image in the far red (630-700 nm) spectrum, where the melanin in the iris reflects light to appear brighter in constrast to the dark pupil. Using a convolutional neural network, the proposed system measures pupil diameter as it dynamically changes in a frame by frame video. Comparing across 4 different smartphone models, the pupil-iris contrast of N = 12 participants increases by an average of 451% with the proposed system. In a validation study of N = 11 participants comparing the relative pupil change in the proposed system to a Neuroptics PLR-3000 Pupillometer during a pupillary light response test, the prototype system acheived a mean absolute error of 2.4%.
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Affiliation(s)
- Colin Barry
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA, USA.
- Design Lab, University of California San Diego, La Jolla, CA, USA.
| | - Edward Wang
- Electrical and Computer Engineering Department, University of California San Diego, La Jolla, CA, USA
- Design Lab, University of California San Diego, La Jolla, CA, USA
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6
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Kuwamizu R, Yamazaki Y, Aoike N, Hiraga T, Hata T, Yassa MA, Soya H. Pupil dynamics during very light exercise predict benefits to prefrontal cognition. Neuroimage 2023; 277:120244. [PMID: 37353097 PMCID: PMC10788147 DOI: 10.1016/j.neuroimage.2023.120244] [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: 03/20/2023] [Revised: 06/12/2023] [Accepted: 06/20/2023] [Indexed: 06/25/2023] Open
Abstract
Physical exercise, even stress-free very-light-intensity exercise such as yoga and very slow running, can have beneficial effects on executive function, possibly by potentiating prefrontal cortical activity. However, the exact mechanisms underlying this potentiation have not been identified. Evidence from studies using pupillometry demonstrates that pupil changes track the real-time dynamics of activity linked to arousal and attention, including neural circuits from the locus coeruleus to the cortex. This makes it possible to examine whether pupil-linked brain dynamics induced during very-light-intensity exercise mediate benefits to prefrontal executive function in healthy young adults. In this experiment, pupil diameter was measured during 10 min of very-light-intensity exercise (30% V˙o2peak). A Stroop task was used to assess executive function before and after exercise. Prefrontal cortical activation during the task was assessed using multichannel functional near-infrared spectroscopy (fNIRS). We observed that very-light-intensity exercise significantly elicited pupil dilation, reduction of Stroop interference, and task-related left dorsolateral prefrontal cortex activation compared with the resting-control condition. The magnitude of change in pupil dilation predicted the magnitude of improvement in Stroop performance. In addition, causal mediation analysis showed that pupil dilation during very-light-intensity exercise robustly determined subsequent enhancement of Stroop performance. This finding supports our hypothesis that the pupil-linked mechanisms, which may be tied to locus coeruleus activation, are a potential mechanism by which very light exercise enhances prefrontal cortex activation and executive function. It also suggests that pupillometry may be a useful tool to interpret the beneficial impact of exercise on boosting cognition.
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Affiliation(s)
- Ryuta Kuwamizu
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan; Graduate School of Letters, Kyoto University, Kyoto 606-8501, Japan
| | - Yudai Yamazaki
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan; Sport Neuroscience Division, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan
| | - Naoki Aoike
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan; Sport Neuroscience Division, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan
| | - Taichi Hiraga
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan
| | - Toshiaki Hata
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan
| | - Michael A Yassa
- Sport Neuroscience Division, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan; Department of Neurobiology and Behavior and Center for the Neurobiology of Learning and Memory, University of California Irvine, Irvine, CA 92679-3800, USA
| | - Hideaki Soya
- Laboratory of Exercise Biochemistry and Neuroendocrinology, Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan; Sport Neuroscience Division, Advanced Research Initiative for Human High Performance (ARIHHP), Faculty of Health and Sport Sciences, University of Tsukuba, Ibaraki 305-8574, Japan.
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7
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Hussain A, Sheikh Z, Subramanian M. The Eye as a Diagnostic Tool for Alzheimer’s Disease. Life (Basel) 2023; 13:life13030726. [PMID: 36983883 PMCID: PMC10052959 DOI: 10.3390/life13030726] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 02/23/2023] [Accepted: 03/04/2023] [Indexed: 03/10/2023] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder impacting cognition, function, and behavior in the elderly population. While there are currently no disease-modifying agents capable of curing AD, early diagnosis and management in the preclinical stage can significantly improve patient morbidity and life expectancy. Currently, the diagnosis of Alzheimer’s disease is a clinical one, often supplemented by invasive and expensive biomarker testing. Over the last decade, significant advancements have been made in our understanding of AD and the role of ocular tissue as a potential biomarker. Ocular biomarkers hold the potential to provide noninvasive and easily accessible diagnostic and monitoring capabilities. This review summarizes current research for detecting biomarkers of Alzheimer’s disease in ocular tissue.
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8
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Tokushige SI, Matsumoto H, Matsuda SI, Inomata-Terada S, Kotsuki N, Hamada M, Tsuji S, Ugawa Y, Terao Y. Early detection of cognitive decline in Alzheimer's disease using eye tracking. Front Aging Neurosci 2023; 15:1123456. [PMID: 37025964 PMCID: PMC10070704 DOI: 10.3389/fnagi.2023.1123456] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/06/2023] [Indexed: 04/08/2023] Open
Abstract
Background Patients with Alzheimer's disease (AD) are known to exhibit visuospatial processing impairment, as reflected in eye movements from the early stages of the disease. We investigated whether the pattern of gaze exploration during visual tasks could be useful for detecting cognitive decline at the earliest stage. Methods Sixteen AD patients (age: 79.1 ± 7.9 years, Mini Mental State Examination [MMSE] score: 17.7 ± 5.3, mean ± standard deviation) and 16 control subjects (age: 79.4 ± 4.6, MMSE score: 26.9 ± 2.4) participated. In the visual memory task, subjects memorized presented line drawings for later recall. In the visual search tasks, they searched for a target Landolt ring of specific orientation (serial search task) or color (pop-out task) embedded among arrays of distractors. Using video-oculography, saccade parameters, patterns of gaze exploration, and pupil size change during task performance were recorded and compared between AD and control subjects. Results In the visual memory task, the number of informative regions of interest (ROIs) fixated was significantly reduced in AD patients compared to control subjects. In the visual search task, AD patients took a significantly longer time and more saccades to detect the target in the serial but not in pop-out search. In both tasks, there was no significant difference in the saccade frequency and amplitude between groups. On-task pupil modulation during the serial search task was decreased in AD. The number of ROIs fixated in the visual memory task and search time and saccade numbers in the serial search task differentiated both groups of subjects with high sensitivity, whereas saccade parameters of pupil size modulation were effective in confirming normal cognition from cognitive decline with high specificity. Discussion Reduced fixation on informative ROIs reflected impaired attentional allocation. Increased search time and saccade numbers in the visual search task indicated inefficient visual processing. Decreased on-task pupil size during visual search suggested decreased pupil modulation with cognitive load in AD patients, reflecting impaired function of the locus coeruleus. When patients perform the combination of these tasks to visualize multiple aspects of visuospatial processing, cognitive decline can be detected at an early stage with high sensitivity and specificity and its progression be evaluated.
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Affiliation(s)
- Shin-ichi Tokushige
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Department of Neurology, Kyorin University, Tokyo, Japan
| | | | | | | | - Naoki Kotsuki
- Department of Neurology, Kyorin University, Tokyo, Japan
| | - Masashi Hamada
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
| | - Shoji Tsuji
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Institute of Medical Genomics, International University of Health and Welfare, Chiba, Japan
| | - Yoshikazu Ugawa
- Department of Human Neurophysiology, Fukushima Medical University, Fukushima, Japan
| | - Yasuo Terao
- Department of Neurology, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan
- Department of Medical Physiology, Kyorin University, Tokyo, Japan
- *Correspondence: Yasuo Terao,
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9
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Minné D, Marnewick JL, Engel-Hills P. Early Chronic Stress Induced Changes within the Locus Coeruleus in Sporadic Alzheimer's Disease. Curr Alzheimer Res 2023; 20:301-317. [PMID: 37872793 DOI: 10.2174/1567205020666230811092956] [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: 02/27/2023] [Revised: 06/30/2023] [Accepted: 07/04/2023] [Indexed: 10/25/2023]
Abstract
Chronic exposure to stress throughout the lifespan has been the focus of many studies on Alzheimer's disease (AD) because of the similarities between the biological mechanisms involved in chronic stress and the pathophysiology of AD. In fact, the earliest abnormality associated with the disease is the presence of phosphorylated tau protein in locus coeruleus neurons, a brain structure highly responsive to stress and perceived threat. Here, we introduce allostatic load as a useful concept for understanding many of the complex, interacting neuropathological changes involved in the AD degenerative process. In response to chronic stress, aberrant tau proteins that begin to accumulate within the locus coeruleus decades prior to symptom onset appear to represent a primary pathological event in the AD cascade, triggering a wide range of interacting brain changes involving neuronal excitotoxicity, endocrine alterations, inflammation, oxidative stress, and amyloid plaque exacerbation. While it is acknowledged that stress will not necessarily be the major precipitating factor in all cases, early tau-induced changes within the locus coeruleus-norepinephrine pathway suggests that a therapeutic window might exist for preventative measures aimed at managing stress and restoring balance within the HPA axis.
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Affiliation(s)
- Donné Minné
- Applied Microbial & Health Biotechnology Institute, Cape Peninsula University of Technology, Cape Town, 7535, South Africa
- Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, Cape Town, 7535, South Africa
| | - Jeanine L Marnewick
- Applied Microbial & Health Biotechnology Institute, Cape Peninsula University of Technology, Cape Town, 7535, South Africa
| | - Penelope Engel-Hills
- Faculty of Health and Wellness Sciences, Cape Peninsula University of Technology, Cape Town, 7535, South Africa
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Zeeman M, Figeys M, Brimmo T, Burnstad C, Hao J, Kim ES. Task-Evoked Pupillary Response as a Potential Biomarker of Dementia and Mild Cognitive Impairment: A Scoping Review. Am J Alzheimers Dis Other Demen 2023; 38:15333175231160010. [PMID: 36896819 PMCID: PMC10580717 DOI: 10.1177/15333175231160010] [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] [Indexed: 03/11/2023]
Abstract
Pupil dilation functions as a proxy for cognitive effort and can be measured through automated pupillometry. The aim of this scoping review is to examine how individuals with cognitive impairment differ in task-evoked pupillary responses relative to cognitively healthy individuals. A systematic literature search across six databases was conducted to identify studies examining changes in pupillary responses evoked by cognitive tasks comparing patients with dementia to healthy controls. Eight articles met inclusion criteria and were included for review. Differences in task-evoked pupillary response between cognitively impaired and cognitively healthy participants were observed across studies. Pupil dilation is decreased in patients with Alzheimer's Disease compared to controls, with no difference observed in patients with mild cognitive impairment. A mild, non-significant trend towards reduced pupil dilation in patients with either Parkinson's Disease or Dementia with Lewy Bodies suggests a similar but less pronounced effect than in AD patients. Further research is required to examine the utility of task-evoked pupillary responses as a potential biomarker indexing cognitive decline in individuals transitioning to mild cognitive impairment and/or dementia.
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Affiliation(s)
- Michael Zeeman
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Mathieu Figeys
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
| | - Tolani Brimmo
- Faculty of Science, University of Alberta, Edmonton, AB, Canada
| | - Cleo Burnstad
- Faculty of Science, University of Alberta, Edmonton, AB, Canada
| | - Jasmine Hao
- Faculty of Medicine and Dentistry, University of Alberta, Edmonton, AB, Canada
| | - Esther S Kim
- Faculty of Rehabilitation Medicine, University of Alberta, Edmonton, AB, Canada
- Department of Communication Sciences and Disorders, University of Alberta, Edmonton, Canada
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11
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Caligiore D, Giocondo F, Silvetti M. The Neurodegenerative Elderly Syndrome (NES) hypothesis: Alzheimer and Parkinson are two faces of the same disease. IBRO Neurosci Rep 2022; 13:330-343. [PMID: 36247524 PMCID: PMC9554826 DOI: 10.1016/j.ibneur.2022.09.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 09/07/2022] [Accepted: 09/21/2022] [Indexed: 11/25/2022] Open
Abstract
Increasing evidence suggests that Alzheimer's disease (AD) and Parkinson's disease (PD) share monoamine and alpha-synuclein (αSyn) dysfunctions, often beginning years before clinical manifestations onset. The triggers for these impairments and the causes leading these early neurodegenerative processes to become AD or PD remain unclear. We address these issues by proposing a radically new perspective to frame AD and PD: they are different manifestations of one only disease we call "Neurodegenerative Elderly Syndrome (NES)". NES goes through three phases. The seeding stage, which starts years before clinical signs, and where the part of the brain-body affected by the initial αSyn and monoamine dysfunctions, influences the future possible progression of NES towards PD or AD. The compensatory stage, where the clinical symptoms are still silent thanks to compensatory mechanisms keeping monoamine concentrations homeostasis. The bifurcation stage, where NES becomes AD or PD. We present recent literature supporting NES and discuss how this hypothesis could radically change the comprehension of AD and PD comorbidities and the design of novel system-level diagnostic and therapeutic actions.
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Affiliation(s)
- Daniele Caligiore
- Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council (CTNLab-ISTC-CNR), Via San Martino della Battaglia 44, Rome 00185, Italy
- AI2Life s.r.l., Innovative Start-Up, ISTC-CNR Spin-Off, Via Sebino 32, Rome 00199, Italy
| | - Flora Giocondo
- Laboratory of Embodied Natural and Artificial Intelligence, Institute of Cognitive Sciences and Technologies, National Research Council (LENAI-ISTC-CNR), Via San Martino della Battaglia 44, Rome 00185, Italy
| | - Massimo Silvetti
- Computational and Translational Neuroscience Laboratory, Institute of Cognitive Sciences and Technologies, National Research Council (CTNLab-ISTC-CNR), Via San Martino della Battaglia 44, Rome 00185, Italy
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12
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The pupil constriction to light is associated with cognitive measures in middle-aged and older adults. Aging Clin Exp Res 2022; 34:1655-1662. [PMID: 35267180 DOI: 10.1007/s40520-022-02097-w] [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: 11/30/2021] [Accepted: 02/16/2022] [Indexed: 11/01/2022]
Abstract
AIMS The evidence relating the pupil light reflex (PLR) and cognition have been inconsistent. In this cross-sectional study, we evaluated the association between the PLR and cognition in community-dwelling middle-aged and older individuals. METHODS Pupil reactivity was recorded in a subgroup of 403 participants (mean age 60.7 years, 57.3% females) in an epidemiologic study of aging. Ten pupil parameters were calculated to describe pupil constriction to light stimuli. A principal component analysis (PCA) score was used to calculate an overall performance over four cognitive testings. Linear regression was used to assess the association between pupil parameters and PCA scores, adjusting for age, sex, education, medications, health-related quality of life questionnaire, and systemic and ocular comorbidities. RESULTS The PCA scores decreased by 0.039 [95% CI (- 0.050, - 0.028)] per year increase in age and were lower in males than females by 0.76 [95% CI (- 0.96, - 0.55)] (p < 0.001). Pupil constriction amplitude in millimeters and the duration from stimulus onset to maximal constriction velocity were significantly associated with cognition after adjusting for (1) age and sex and (2) age, sex, and multiple covariates (p < 0.05). CONCLUSIONS In this study, we provided moderate evidence suggesting the association between PLR and neuropsychological cognitive measures. The findings suggest the potential of pupil reactivity to serve as a biomarker of brain aging and warrant further longitudinal study to assess if changes in the PLR can predict cognitive decline over time.
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Maloca PM, Carvalho ER, Hasler PW, Balaskas K, Inglin N, Petzold A, Egan C, Tufail A, Scholl HPN, Valmaggia P. Dynamic volume-rendered optical coherence tomography pupillometry. Acta Ophthalmol 2021; 100:654-664. [PMID: 34750988 DOI: 10.1111/aos.15063] [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: 11/16/2020] [Revised: 09/29/2021] [Accepted: 10/25/2021] [Indexed: 11/29/2022]
Abstract
PURPOSE To assess intrapupillary space (IPS) changes in healthy subjects with regard to decreased iris motility in patients with pseudoexfoliation glaucoma (PEXG) or non-arteritic anterior ischaemic optic neuropathy (NAION) in a feasibility study in a clinical environment. METHODS Scotopic and photopic IPS measurements using three-dimensionally rendered swept-source optical coherence tomography (SS-OCT) data were obtained and compared for all subjects. Intrapupillary space (IPS) parameters were evaluated such as absolute volumetric differences, relative light response for volumetric ratios and pupillary ejection fraction (PEF) for functional contraction measurements. RESULTS From a total of 122 IPS from 66 subjects, 106 IPS were eligible for comparison providing values for 72 normal, 30 PEXG and 4 NAION eyes. In healthy, PEXG and NAION subjects, scotopic overall mean IPS was 8.90, 3.45 and 4.16 mm3 , and photopic overall mean IPS was 0.87, 0.74 and 1.13 mm3 , respectively. Three-dimensional contractility showed a mean absolute difference of 8.03 mm3 for normals (defined as 100% contractility), 2.72 mm3 for PEXG (33.88% of normal) and 3.03 mm3 for NAION (38.50% of normal) with a relative light response ratio between scotopic and photopic volumes of 10.26 (100%), 4.69 (45.70%) and 3.67 (35.78%), respectively. Pupillary ejection fraction (PEF) showed a contractile pupillary emptying of 88.11% for normals, 76.92% for PEXG and 70.91% for NAION patients. CONCLUSION This 3D pupillometry OCT assessment allows for quantitative measurements of pupil function, contractility and response to light. More specifically, PEF is presented as a potential (neuro)-pupillary outcome measure that could be useful in the monitoring of ophthalmic disorders that affect pupillary function.
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Affiliation(s)
- Peter M. Maloca
- Institute of Molecular and Clinical Ophthalmology Basel (IOB) Basel Switzerland
- OCTlab Department of Ophthalmology University Hospital Basel Basel Switzerland
- Department of Ophthalmology University of Basel Basel Switzerland
- Moorfields Eye Hospital London UK
| | | | - Pascal W. Hasler
- OCTlab Department of Ophthalmology University Hospital Basel Basel Switzerland
- Department of Ophthalmology University of Basel Basel Switzerland
| | | | - Nadja Inglin
- Institute of Molecular and Clinical Ophthalmology Basel (IOB) Basel Switzerland
| | - Axel Petzold
- Moorfields Eye Hospital London UK
- National Hospital for Neurology and Neurosurgery UCLH & UCL Institute of Neurology Queen Square London UK
- Dutch Expertise Centre Neuro‐ophthalmology Amsterdam UMC The Netherlands
| | | | | | - Hendrik P. N. Scholl
- Institute of Molecular and Clinical Ophthalmology Basel (IOB) Basel Switzerland
- OCTlab Department of Ophthalmology University Hospital Basel Basel Switzerland
- Department of Ophthalmology University of Basel Basel Switzerland
| | - Philippe Valmaggia
- Institute of Molecular and Clinical Ophthalmology Basel (IOB) Basel Switzerland
- OCTlab Department of Ophthalmology University Hospital Basel Basel Switzerland
- Department of Ophthalmology University of Basel Basel Switzerland
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Caligiore D, Silvetti M, D'Amelio M, Puglisi-Allegra S, Baldassarre G. Computational Modeling of Catecholamines Dysfunction in Alzheimer's Disease at Pre-Plaque Stage. J Alzheimers Dis 2021; 77:275-290. [PMID: 32741822 PMCID: PMC7592658 DOI: 10.3233/jad-200276] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Background: Alzheimer’s disease (AD) etiopathogenesis remains partially unexplained. The main conceptual framework used to study AD is the Amyloid Cascade Hypothesis, although the failure of recent clinical experimentation seems to reduce its potential in AD research. Objective: A possible explanation for the failure of clinical trials is that they are set too late in AD progression. Recent studies suggest that the ventral tegmental area (VTA) degeneration could be one of the first events occurring in AD progression (pre-plaque stage). Methods: Here we investigate this hypothesis through a computational model and computer simulations validated with behavioral and neural data from patients. Results: We show that VTA degeneration might lead to system-level adjustments of catecholamine release, triggering a sequence of events leading to relevant clinical and pathological signs of AD. These changes consist first in a midfrontal-driven compensatory hyperactivation of both VTA and locus coeruleus (norepinephrine) followed, with the progression of the VTA impairment, by a downregulation of catecholamine release. These processes could then trigger the neural degeneration at the cortical and hippocampal levels, due to the chronic loss of the neuroprotective role of norepinephrine. Conclusion: Our novel hypothesis might contribute to the formulation of a wider system-level view of AD which might help to devise early diagnostic and therapeutic interventions.
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Affiliation(s)
- Daniele Caligiore
- Computational and Translational Neuroscience Laboratory (CTNLab), Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
| | - Massimo Silvetti
- Computational and Translational Neuroscience Laboratory (CTNLab), Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
| | - Marcello D'Amelio
- Unit of Molecular Neurosciences, Department of Medicine, University Campus-Biomedico, Rome, Italy.,IRCCS Santa Lucia Foundation, Rome, Italy
| | | | - Gianluca Baldassarre
- Laboratory of Computational Embodied Neuroscience (LOCEN), Institute of Cognitive Sciences and Technologies, National Research Council, Rome, Italy
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15
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Patthy Á, Murai J, Hanics J, Pintér A, Zahola P, Hökfelt TGM, Harkany T, Alpár A. Neuropathology of the Brainstem to Mechanistically Understand and to Treat Alzheimer's Disease. J Clin Med 2021; 10:jcm10081555. [PMID: 33917176 PMCID: PMC8067882 DOI: 10.3390/jcm10081555] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Revised: 04/01/2021] [Accepted: 04/05/2021] [Indexed: 12/18/2022] Open
Abstract
Alzheimer’s disease (AD) is a devastating neurodegenerative disorder as yet without effective therapy. Symptoms of this disorder typically reflect cortical malfunction with local neurohistopathology, which biased investigators to search for focal triggers and molecular mechanisms. Cortex, however, receives massive afferents from caudal brain structures, which do not only convey specific information but powerfully tune ensemble activity. Moreover, there is evidence that the start of AD is subcortical. The brainstem harbors monoamine systems, which establish a dense innervation in both allo- and neocortex. Monoaminergic synapses can co-release neuropeptides either by precisely terminating on cortical neurons or, when being “en passant”, can instigate local volume transmission. Especially due to its early damage, malfunction of the ascending monoaminergic system emerges as an early sign and possible trigger of AD. This review summarizes the involvement and cascaded impairment of brainstem monoaminergic neurons in AD and discusses cellular mechanisms that lead to their dysfunction. We highlight the significance and therapeutic challenges of transmitter co-release in ascending activating system, describe the role and changes of local connections and distant afferents of brainstem nuclei in AD, and summon the rapidly increasing diagnostic window during the last few years.
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Affiliation(s)
- Ágoston Patthy
- Department of Anatomy, Semmelweis University, H-1094 Budapest, Hungary; (Á.P.); (J.M.); (J.H.); (A.P.); (P.Z.)
| | - János Murai
- Department of Anatomy, Semmelweis University, H-1094 Budapest, Hungary; (Á.P.); (J.M.); (J.H.); (A.P.); (P.Z.)
| | - János Hanics
- Department of Anatomy, Semmelweis University, H-1094 Budapest, Hungary; (Á.P.); (J.M.); (J.H.); (A.P.); (P.Z.)
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Hungarian Academy of Sciences, H-1094 Budapest, Hungary
| | - Anna Pintér
- Department of Anatomy, Semmelweis University, H-1094 Budapest, Hungary; (Á.P.); (J.M.); (J.H.); (A.P.); (P.Z.)
| | - Péter Zahola
- Department of Anatomy, Semmelweis University, H-1094 Budapest, Hungary; (Á.P.); (J.M.); (J.H.); (A.P.); (P.Z.)
| | - Tomas G. M. Hökfelt
- Department of Neuroscience, Biomedicum 7D, Karolinska Institutet, 17165 Stockholm, Sweden; (T.G.M.H.); (T.H.)
| | - Tibor Harkany
- Department of Neuroscience, Biomedicum 7D, Karolinska Institutet, 17165 Stockholm, Sweden; (T.G.M.H.); (T.H.)
- Center for Brain Research, Department of Molecular Neurosciences, Medical University of Vienna, 1090 Vienna, Austria
| | - Alán Alpár
- Department of Anatomy, Semmelweis University, H-1094 Budapest, Hungary; (Á.P.); (J.M.); (J.H.); (A.P.); (P.Z.)
- SE NAP Research Group of Experimental Neuroanatomy and Developmental Biology, Hungarian Academy of Sciences, H-1094 Budapest, Hungary
- Correspondence:
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Abstract
The eye and brain share common mechanisms of aging and disease, thus the retina is an essential source of accessible information about neurodegenerative processes occurring in the brain. Advances in retinal imaging have led to the discovery of many potential biomarkers of Alzheimer's disease, although further research is needed to validate these associations. Understanding the mechanisms of retinal disease in the context of aging will extend our knowledge of AD and may enable advancements in diagnosis, monitoring, and treatment.
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17
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Zhou X, Li YYT, Fu AKY, Ip NY. Polygenic Score Models for Alzheimer's Disease: From Research to Clinical Applications. Front Neurosci 2021; 15:650220. [PMID: 33854414 PMCID: PMC8039467 DOI: 10.3389/fnins.2021.650220] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2021] [Accepted: 03/09/2021] [Indexed: 12/13/2022] Open
Abstract
The high prevalence of Alzheimer's disease (AD) among the elderly population and its lack of effective treatments make this disease a critical threat to human health. Recent epidemiological and genetics studies have revealed the polygenic nature of the disease, which is possibly explainable by a polygenic score model that considers multiple genetic risks. Here, we systemically review the rationale and methods used to construct polygenic score models for studying AD. We also discuss the associations of polygenic risk scores (PRSs) with clinical outcomes, brain imaging findings, and biochemical biomarkers from both the brain and peripheral system. Finally, we discuss the possibility of incorporating polygenic score models into research and clinical practice along with potential challenges.
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Affiliation(s)
- Xiaopu Zhou
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen–Hong Kong Institute of Brain Science, Shenzhen, China
| | - Yolanda Y. T. Li
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China
| | - Amy K. Y. Fu
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen–Hong Kong Institute of Brain Science, Shenzhen, China
| | - Nancy Y. Ip
- Division of Life Science, State Key Laboratory of Molecular Neuroscience and Molecular Neuroscience Center, The Hong Kong University of Science and Technology, Hong Kong, China
- Hong Kong Center for Neurodegenerative Diseases, Hong Kong Science Park, Hong Kong, China
- Guangdong Provincial Key Laboratory of Brain Science, Disease and Drug Development, HKUST Shenzhen Research Institute, Shenzhen–Hong Kong Institute of Brain Science, Shenzhen, China
- *Correspondence: Nancy Y. Ip,
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18
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Devos H, Gustafson K, Ahmadnezhad P, Liao K, Mahnken JD, Brooks WM, Burns JM. Psychometric Properties of NASA-TLX and Index of Cognitive Activity as Measures of Cognitive Workload in Older Adults. Brain Sci 2020; 10:E994. [PMID: 33339224 PMCID: PMC7766152 DOI: 10.3390/brainsci10120994] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/01/2020] [Accepted: 12/14/2020] [Indexed: 11/16/2022] Open
Abstract
Cognitive workload is increasingly recognized as an important determinant of performance in cognitive tests and daily life activities. Cognitive workload is a measure of physical and mental effort allocation to a task, which can be determined through self-report or physiological measures. However, the reliability and validity of these measures have not been established in older adults with a wide range of cognitive ability. The aim of this study was to establish the test-retest reliability of the National Aeronautics and Space Administration Task Load Index (NASA-TLX) and Index of Cognitive Activity (ICA), extracted from pupillary size. The convergent validity of these measures against event-related potentials (ERPs) was also investigated. A total of 38 individuals with scores on the Montreal Cognitive Assessment ranging between 17 and 30 completed a working memory test (n-back) with three levels of difficulty at baseline and at a two-week follow-up. The intraclass correlation coefficients (ICC) values of the NASA-TLX ranged between 0.71 and 0.81, demonstrating good to excellent reliability. The mean ICA scores showed fair to good reliability, with ICCs ranging between 0.56 and 0.73. The mean ICA and NASA-TLX scores showed significant and moderate correlations (Pearson's r ranging between 0.30 and 0.33) with the third positive peak of the ERP at the midline channels. We conclude that ICA and NASA-TLX are reliable measures of cognitive workload in older adults. Further research is needed in dissecting the subjective and objective constructs of cognitive workload.
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Affiliation(s)
- Hannes Devos
- Laboratory for Advanced Rehabilitation Research in Simulation, Department of Physical Therapy and Rehabilitation Science, University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | - Kathleen Gustafson
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (K.G.); (W.M.B.); (J.M.B.)
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | - Pedram Ahmadnezhad
- Laboratory for Advanced Rehabilitation Research in Simulation, Department of Physical Therapy and Rehabilitation Science, University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | - Ke Liao
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | - Jonathan D. Mahnken
- University of Kansas Alzheimer’s Disease Center, University of Kansas Medical Center, Kansas City, KS 66160, USA;
- Department of Biostatistics & Data Science, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - William M. Brooks
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (K.G.); (W.M.B.); (J.M.B.)
- Hoglund Brain Imaging Center, University of Kansas Medical Center, Kansas City, KS 66160, USA;
- University of Kansas Alzheimer’s Disease Center, University of Kansas Medical Center, Kansas City, KS 66160, USA;
| | - Jeffrey M. Burns
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA; (K.G.); (W.M.B.); (J.M.B.)
- University of Kansas Alzheimer’s Disease Center, University of Kansas Medical Center, Kansas City, KS 66160, USA;
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Kelberman M, Keilholz S, Weinshenker D. What's That (Blue) Spot on my MRI? Multimodal Neuroimaging of the Locus Coeruleus in Neurodegenerative Disease. Front Neurosci 2020; 14:583421. [PMID: 33122996 PMCID: PMC7573566 DOI: 10.3389/fnins.2020.583421] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 09/16/2020] [Indexed: 01/04/2023] Open
Abstract
The locus coeruleus (LC) has long been underappreciated for its role in the pathophysiology of Alzheimer’s disease (AD), Parkinson’s disease (PD), and other neurodegenerative disorders. While AD and PD are distinct in clinical presentation, both are characterized by prodromal protein aggregation in the LC, late-stage degeneration of the LC, and comorbid conditions indicative of LC dysfunction. Many of these early studies were limited to post-mortem histological techniques due to the LC’s small size and location deep in the brainstem. Thus, there is a growing interest in utilizing in vivo imaging of the LC as a predictor of preclinical neurodegenerative processes and biomarker of disease progression. Simultaneously, neuroimaging in animal models of neurodegenerative disease holds promise for identifying early alterations to LC circuits, but has thus far been underutilized. While still in its infancy, a handful of studies have reported effects of single gene mutations and pathology on LC function in disease using various neuroimaging techniques. Furthermore, combining imaging and optogenetics or chemogenetics allows for interrogation of network connectivity in response to changes in LC activity. The purpose of this article is twofold: (1) to review what magnetic resonance imaging (MRI) and positron emission tomography (PET) have revealed about LC dysfunction in neurodegenerative disease and its potential as a biomarker in humans, and (2) to explore how animal models can be used to test hypotheses derived from clinical data and establish a mechanistic framework to inform LC-focused therapeutic interventions to alleviate symptoms and impede disease progression.
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Affiliation(s)
- Michael Kelberman
- Department of Human Genetics, Emory University, Atlanta, GA, United States
| | - Shella Keilholz
- The Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology, Emory University, Atlanta, GA, United States
| | - David Weinshenker
- Department of Human Genetics, Emory University, Atlanta, GA, United States
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20
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Retinal Degeneration and Alzheimer's Disease: An Evolving Link. Int J Mol Sci 2020; 21:ijms21197290. [PMID: 33023198 PMCID: PMC7582766 DOI: 10.3390/ijms21197290] [Citation(s) in RCA: 69] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 09/15/2020] [Accepted: 09/25/2020] [Indexed: 12/13/2022] Open
Abstract
Age-related macular degeneration (AMD) and glaucoma are degenerative conditions of the retina and a significant cause of irreversible blindness in developed countries. Alzheimer’s disease (AD), the most common dementia of the elderly, is often associated with AMD and glaucoma. The cardinal features of AD include extracellular accumulation of amyloid β (Aβ) and intracellular deposits of hyper-phosphorylated tau (p-tau). Neuroinflammation and brain iron dyshomeostasis accompany Aβ and p-tau deposits and, together, lead to progressive neuronal death and dementia. The accumulation of Aβ and iron in drusen, the hallmark of AMD, and Aβ and p-tau in retinal ganglion cells (RGC), the main retinal cell type implicated in glaucoma, and accompanying inflammation suggest overlapping pathology. Visual abnormalities are prominent in AD and are believed to develop before cognitive decline. Some are caused by degeneration of the visual cortex, while others are due to RGC loss or AMD-associated retinal degeneration. Here, we review recent information on Aβ, p-tau, chronic inflammation, and iron dyshomeostasis as common pathogenic mechanisms linking the three degenerative conditions, and iron chelation as a common therapeutic option for these disorders. Additionally discussed is the role of prion protein, infamous for prion disorders, in Aβ-mediated toxicity and, paradoxically, in neuroprotection.
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21
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Wu SZ, Masurkar AV, Balcer LJ. Afferent and Efferent Visual Markers of Alzheimer's Disease: A Review and Update in Early Stage Disease. Front Aging Neurosci 2020; 12:572337. [PMID: 33061906 PMCID: PMC7518395 DOI: 10.3389/fnagi.2020.572337] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Accepted: 08/20/2020] [Indexed: 01/06/2023] Open
Abstract
Vision, which requires extensive neural involvement, is often impaired in Alzheimer's disease (AD). Over the last few decades, accumulating evidence has shown that various visual functions and structures are compromised in Alzheimer's dementia and when measured can detect those with dementia from those with normal aging. These visual changes involve both the afferent and efferent parts of the visual system, which correspond to the sensory and eye movement aspects of vision, respectively. There are fewer, but a growing number of studies, that focus on the detection of predementia stages. Visual biomarkers that detect these stages are paramount in the development of successful disease-modifying therapies by identifying appropriate research participants and in identifying those who would receive future therapies. This review provides a summary and update on common afferent and efferent visual markers of AD with a focus on mild cognitive impairment (MCI) and preclinical disease detection. We further propose future directions in this area. Given the ease of performing visual tests, the accessibility of the eye, and advances in ocular technology, visual measures have the potential to be effective, practical, and non-invasive biomarkers of AD.
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Affiliation(s)
- Shirley Z. Wu
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Ophthalmology, New York University Grossman School of Medicine, New York, NY, United States
| | - Arjun V. Masurkar
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
| | - Laura J. Balcer
- Department of Neurology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Ophthalmology, New York University Grossman School of Medicine, New York, NY, United States
- Department of Population Health, New York University Grossman School of Medicine, New York, NY, United States
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Mirzaei N, Shi H, Oviatt M, Doustar J, Rentsendorj A, Fuchs DT, Sheyn J, Black KL, Koronyo Y, Koronyo-Hamaoui M. Alzheimer's Retinopathy: Seeing Disease in the Eyes. Front Neurosci 2020; 14:921. [PMID: 33041751 PMCID: PMC7523471 DOI: 10.3389/fnins.2020.00921] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 08/10/2020] [Indexed: 01/18/2023] Open
Abstract
The neurosensory retina emerges as a prominent site of Alzheimer's disease (AD) pathology. As a CNS extension of the brain, the neuro retina is easily accessible for noninvasive, high-resolution imaging. Studies have shown that along with cognitive decline, patients with mild cognitive impairment (MCI) and AD often suffer from visual impairments, abnormal electroretinogram patterns, and circadian rhythm disturbances that can, at least in part, be attributed to retinal damage. Over a decade ago, our group identified the main pathological hallmark of AD, amyloid β-protein (Aβ) plaques, in the retina of patients including early-stage clinical cases. Subsequent histological, biochemical and in vivo retinal imaging studies in animal models and in humans corroborated these findings and further revealed other signs of AD neuropathology in the retina. Among these signs, hyperphosphorylated tau, neuronal degeneration, retinal thinning, vascular abnormalities and gliosis were documented. Further, linear correlations between the severity of retinal and brain Aβ concentrations and plaque pathology were described. More recently, extensive retinal pericyte loss along with vascular platelet-derived growth factor receptor-β deficiency were discovered in postmortem retinas of MCI and AD patients. This progressive loss was closely associated with increased retinal vascular amyloidosis and predicted cerebral amyloid angiopathy scores. These studies brought excitement to the field of retinal exploration in AD. Indeed, many questions still remain open, such as queries related to the temporal progression of AD-related pathology in the retina compared to the brain, the relations between retinal and cerebral changes and whether retinal signs can predict cognitive decline. The extent to which AD affects the retina, including the susceptibility of certain topographical regions and cell types, is currently under intense investigation. Advances in retinal amyloid imaging, hyperspectral imaging, optical coherence tomography, and OCT-angiography encourage the use of such modalities to achieve more accurate, patient- and user-friendly, noninvasive detection and monitoring of AD. In this review, we summarize the current status in the field while addressing the many unknowns regarding Alzheimer's retinopathy.
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Affiliation(s)
- Nazanin Mirzaei
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Haoshen Shi
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Mia Oviatt
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Jonah Doustar
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Altan Rentsendorj
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Dieu-Trang Fuchs
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Julia Sheyn
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Keith L. Black
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Yosef Koronyo
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
| | - Maya Koronyo-Hamaoui
- Department of Neurosurgery, Maxine Dunitz Neurosurgical Research Institute, Cedars-Sinai Medical Center, Los Angeles, CA, United States
- Department of Biomedical Sciences, Cedars-Sinai Medical Center, Los Angeles, CA, United States
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