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Sringean J, Udomsirithamrong O, Bhidayasiri R. Too little or too much nocturnal movements in Parkinson's disease: A practical guide to managing the unseen. Clin Park Relat Disord 2024; 10:100258. [PMID: 38845753 PMCID: PMC11153921 DOI: 10.1016/j.prdoa.2024.100258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2024] [Revised: 05/13/2024] [Accepted: 05/21/2024] [Indexed: 06/09/2024] Open
Abstract
Nocturnal and sleep-related motor disorders in people with Parkinson's disease (PD) have a wide spectrum of manifestations and present a complex clinical picture. Problems can arise due to impaired movement ability (hypokinesias), e.g. nocturnal hypokinesia or early-morning akinesia, or to excessive movement (hyperkinesias), e.g. end-of-the-day dyskinesia, parasomnias, periodic limb movement during sleep and restless legs syndrome. These disorders can have a significant negative impact on the sleep, daytime functional ability, and overall quality of life of individuals with PD and their carers. The debilitating motor issues are often accompanied by a combination of non-motor symptoms, including pain and cramping, which add to the overall burden. Importantly, nocturnal motor disorders encompass a broader timeline than just the period of sleep, often starting in the evening, as well as occurring throughout the night and on awakening, and are not just limited to problems of insomnia or sleep fragmentation. Diagnosis can be challenging as, in many cases, the 'gold standard' assessment method is video polysomnography, which may not be available in all settings. Various validated questionnaires are available to support evaluation, and alternative approaches, using wearable sensors and digital technology, are now being developed to facilitate early diagnosis and monitoring. This review sets out the parameters of what can be considered normal nocturnal movement and describes the clinical manifestations, usual clinical or objective assessment methods, and evidence for optimal management strategies for the common nocturnal motor disorders that neurologists will encounter in people with PD in their clinical practice.
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Affiliation(s)
- Jirada Sringean
- Chulalongkorn Centre of Excellence for Parkinson’s Disease & Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Ornanong Udomsirithamrong
- Chulalongkorn Centre of Excellence for Parkinson’s Disease & Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
| | - Roongroj Bhidayasiri
- Chulalongkorn Centre of Excellence for Parkinson’s Disease & Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University and King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok 10330, Thailand
- The Academy of Science, The Royal Society of Thailand, Bangkok 10330, Thailand
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Urtado MB, Rodrigues RD, Fukusima SS. Visual Field Restriction in the Recognition of Basic Facial Expressions: A Combined Eye Tracking and Gaze Contingency Study. Behav Sci (Basel) 2024; 14:355. [PMID: 38785846 PMCID: PMC11117586 DOI: 10.3390/bs14050355] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Revised: 04/05/2024] [Accepted: 04/18/2024] [Indexed: 05/25/2024] Open
Abstract
Uncertainties and discrepant results in identifying crucial areas for emotional facial expression recognition may stem from the eye tracking data analysis methods used. Many studies employ parameters of analysis that predominantly prioritize the examination of the foveal vision angle, ignoring the potential influences of simultaneous parafoveal and peripheral information. To explore the possible underlying causes of these discrepancies, we investigated the role of the visual field aperture in emotional facial expression recognition with 163 volunteers randomly assigned to three groups: no visual restriction (NVR), parafoveal and foveal vision (PFFV), and foveal vision (FV). Employing eye tracking and gaze contingency, we collected visual inspection and judgment data over 30 frontal face images, equally distributed among five emotions. Raw eye tracking data underwent Eye Movements Metrics and Visualizations (EyeMMV) processing. Accordingly, the visual inspection time, number of fixations, and fixation duration increased with the visual field restriction. Nevertheless, the accuracy showed significant differences among the NVR/FV and PFFV/FV groups, despite there being no difference in NVR/PFFV. The findings underscore the impact of specific visual field areas on facial expression recognition, highlighting the importance of parafoveal vision. The results suggest that eye tracking data analysis methods should incorporate projection angles extending to at least the parafoveal level.
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Affiliation(s)
- Melina Boratto Urtado
- Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, Brazil;
| | | | - Sergio Sheiji Fukusima
- Faculty of Philosophy, Sciences and Letters at Ribeirão Preto, University of São Paulo, Ribeirão Preto 14040-901, Brazil;
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Haghshomar M, Dolatshahi M, Ghazi Sherbaf F, Sanjari Moghaddam H, Shirin Shandiz M, Aarabi MH. Disruption of Inferior Longitudinal Fasciculus Microstructure in Parkinson's Disease: A Systematic Review of Diffusion Tensor Imaging Studies. Front Neurol 2018; 9:598. [PMID: 30093877 PMCID: PMC6070770 DOI: 10.3389/fneur.2018.00598] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Accepted: 07/05/2018] [Indexed: 12/19/2022] Open
Abstract
Parkinson's disease (PD) is a neurodegenerative disorder accompanied by a series of pathological mechanisms which contribute to a variety of motor and non-motor symptoms. Recently, there has been an increasing interest in structural diffusion tensor imaging (DTI) in PD which has shed light on our understanding of structural abnormalities underlying PD symptoms or its associations with pathological mechanisms. One of the white matter tracts shown to be disrupted in PD with a possible contribution to some PD symptoms is the inferior longitudinal fasciculus (ILF). On the whole, lower ILF integrity contributes to thought disorders, impaired visual emotions, cognitive impairments such as semantic fluency deficits, and mood disorders. This review outlines the microstructural changes in ILF associated with systemic inflammation and various PD symptoms like cognitive decline, facial emotion recognition deficit, depression, color discrimination deficit, olfactory dysfunction, and tremor genesis. However, few studies have investigated DTI correlates of each symptom and larger studies with standardized imaging protocols are required to extend these preliminary findings and lead to more promising results.
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Affiliation(s)
- Maryam Haghshomar
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | - Mahsa Dolatshahi
- Faculty of Medicine, Tehran University of Medical Sciences, Tehran, Iran
| | | | | | - Mehdi Shirin Shandiz
- Department of Medical Physics, Zahedan University of Medical Sciences, Zahedan, Iran
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Bhidayasiri R, Sringean J, Rattanachaisit W, Truong DD. The sleeping brain in Parkinson's disease: A focus on REM sleep behaviour disorder and related parasomnias for practicing neurologists. J Neurol Sci 2017; 374:32-37. [PMID: 28126342 DOI: 10.1016/j.jns.2017.01.018] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2016] [Revised: 01/04/2017] [Accepted: 01/06/2017] [Indexed: 11/17/2022]
Abstract
Sleep disorders are identified as common non-motor symptoms of Parkinson's disease (PD) and recently this recognition has been expanded to include parasomnias, encompassing not only REM sleep behaviour disorder (RBD), but also other non-REM forms. RBD, a prototypical parasomnia in PD, exists even in the prodromal stage of the disease, and is characterized by the presence of dream enactment behaviours occurring alongside a loss of normal skeletal muscle atonia during REM sleep. In contrast, non-REM parasomnias are more frequently observed in the late stage PD. However, the development of these disorders often overlaps and it is not uncommon for PD patients to meet the criteria for more than one type of parasomnias, thus making a clinical distinction challenging for practicing neurologists who are not sleep specialists. Indeed, clinical recognition of the predominant form of parasomnia does not just depend on video-polysomnography, but also on an individual physician's clinical acumen in delineating pertinent clinical history to determine the most likely diagnosis and proceed accordingly. In this review article, we highlight the various forms of parasomnias that have been reported in PD, including, but not limited to, RBD, with a focus on clinical symptomatology and implications for clinical practice. In addition, we review the differences in PD-related parasomnias compared to those seen in general populations. With advances in sleep research and better technology for ambulatory home monitoring, it is likely that many unanswered questions on PD-related parasomnias will soon be resolved resulting in better management of this nocturnal challenge in PD.
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Affiliation(s)
- Roongroj Bhidayasiri
- Chulalongkorn Centre of Excellence for Parkinson's Disease & Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital and Thai Red Cross Society, Bangkok, Thailand; Department of Rehabilitation Medicine, Juntendo University, Tokyo, Japan.
| | - Jirada Sringean
- Chulalongkorn Centre of Excellence for Parkinson's Disease & Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital and Thai Red Cross Society, Bangkok, Thailand
| | - Watchara Rattanachaisit
- Chulalongkorn Centre of Excellence for Parkinson's Disease & Related Disorders, Department of Medicine, Faculty of Medicine, Chulalongkorn University, King Chulalongkorn Memorial Hospital and Thai Red Cross Society, Bangkok, Thailand
| | - Daniel D Truong
- Parkinson's and Movement Disorders Institute, Fountain Valley, CA, USA
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Högl B, Stefani A. Restless legs syndrome and periodic leg movements in patients with movement disorders: Specific considerations. Mov Disord 2017; 32:669-681. [DOI: 10.1002/mds.26929] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2016] [Accepted: 12/21/2016] [Indexed: 12/25/2022] Open
Affiliation(s)
- Birgit Högl
- Department of Neurology; Medical University of Innsbruck; Innsbruck Austria
| | - Ambra Stefani
- Department of Neurology; Medical University of Innsbruck; Innsbruck Austria
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Suescun J, Ellmore TM, Schiess M. REM Sleep Behavior Disorder: a Prodromal Synucleinopathy. CURRENT GERIATRICS REPORTS 2016. [DOI: 10.1007/s13670-016-0174-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Fernández-Arcos A, Iranzo A, Serradell M, Gaig C, Santamaria J. The Clinical Phenotype of Idiopathic Rapid Eye Movement Sleep Behavior Disorder at Presentation: A Study in 203 Consecutive Patients. Sleep 2016; 39:121-32. [PMID: 26940460 DOI: 10.5665/sleep.5332] [Citation(s) in RCA: 140] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
OBJECTIVE To describe the clinical phenotype of idiopathic rapid eye movement (REM) sleep behavior disorder (IRBD) at presentation in a sleep center. METHODS Clinical history review of 203 consecutive patients with IRBD identified between 1990 and 2014. IRBD was diagnosed by clinical history plus video-polysomnographic demonstration of REM sleep with increased electromyographic activity linked to abnormal behaviors. RESULTS Patients were 80% men with median age at IRBD diagnosis of 68 y (range, 50-85 y). In addition to the already known clinical picture of IRBD, other important features were apparent: 44% of the patients were not aware of their dream-enactment behaviors and 70% reported good sleep quality. In most of these cases bed partners were essential to convince patients to seek medical help. In 11% IRBD was elicited only after specific questioning when patients consulted for other reasons. Seven percent did not recall unpleasant dreams. Leaving the bed occurred occasionally in 24% of subjects in whom dementia with Lewy bodies often developed eventually. For the correct diagnosis of IRBD, video-polysomnography had to be repeated in 16% because of insufficient REM sleep or electromyographic artifacts from coexistent apneas. Some subjects with comorbid obstructive sleep apnea reported partial improvement of RBD symptoms following continuous positive airway pressure therapy. Lack of therapy with clonazepam resulted in an increased risk of sleep related injuries. Synucleinopathy was frequently diagnosed, even in patients with mild severity or uncommon IRBD presentations (e.g., patients who reported sleeping well, onset triggered by a life event, nocturnal ambulation) indicating that the development of a neurodegenerative disease is independent of the clinical presentation of IRBD. CONCLUSIONS We report the largest IRBD cohort observed in a single center to date and highlight frequent features that were not reported or not sufficiently emphasized in previous publications. Physicians should be aware of the full clinical expression of IRBD, a sleep disturbance that represents a neurodegenerative disease. COMMENTARY A commentary on this article appears in this issue on page 7.
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Affiliation(s)
- Ana Fernández-Arcos
- Neurology Service, Multidisciplinary Sleep Disorders Unit, Hospital Clinic de Barcelona, University of Barcelona Medical School, IDIBAPS, CIBERNED, Barcelona, Spain
| | - Alex Iranzo
- Neurology Service, Multidisciplinary Sleep Disorders Unit, Hospital Clinic de Barcelona, University of Barcelona Medical School, IDIBAPS, CIBERNED, Barcelona, Spain
| | - Mónica Serradell
- Neurology Service, Multidisciplinary Sleep Disorders Unit, Hospital Clinic de Barcelona, University of Barcelona Medical School, IDIBAPS, CIBERNED, Barcelona, Spain
| | - Carles Gaig
- Neurology Service, Multidisciplinary Sleep Disorders Unit, Hospital Clinic de Barcelona, University of Barcelona Medical School, IDIBAPS, CIBERNED, Barcelona, Spain
| | - Joan Santamaria
- Neurology Service, Multidisciplinary Sleep Disorders Unit, Hospital Clinic de Barcelona, University of Barcelona Medical School, IDIBAPS, CIBERNED, Barcelona, Spain
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Yaghouby F, Sunderam S. Quasi-supervised scoring of human sleep in polysomnograms using augmented input variables. Comput Biol Med 2015; 59:54-63. [PMID: 25679475 PMCID: PMC4447106 DOI: 10.1016/j.compbiomed.2015.01.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2014] [Revised: 01/04/2015] [Accepted: 01/15/2015] [Indexed: 11/17/2022]
Abstract
The limitations of manual sleep scoring make computerized methods highly desirable. Scoring errors can arise from human rater uncertainty or inter-rater variability. Sleep scoring algorithms either come as supervised classifiers that need scored samples of each state to be trained, or as unsupervised classifiers that use heuristics or structural clues in unscored data to define states. We propose a quasi-supervised classifier that models observations in an unsupervised manner but mimics a human rater wherever training scores are available. EEG, EMG, and EOG features were extracted in 30s epochs from human-scored polysomnograms recorded from 42 healthy human subjects (18-79 years) and archived in an anonymized, publicly accessible database. Hypnograms were modified so that: 1. Some states are scored but not others; 2. Samples of all states are scored but not for transitional epochs; and 3. Two raters with 67% agreement are simulated. A framework for quasi-supervised classification was devised in which unsupervised statistical models-specifically Gaussian mixtures and hidden Markov models--are estimated from unlabeled training data, but the training samples are augmented with variables whose values depend on available scores. Classifiers were fitted to signal features incorporating partial scores, and used to predict scores for complete recordings. Performance was assessed using Cohen's Κ statistic. The quasi-supervised classifier performed significantly better than an unsupervised model and sometimes as well as a completely supervised model despite receiving only partial scores. The quasi-supervised algorithm addresses the need for classifiers that mimic scoring patterns of human raters while compensating for their limitations.
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Affiliation(s)
- Farid Yaghouby
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506-0108, USA
| | - Sridhar Sunderam
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506-0108, USA.
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McCarter SJ, St Louis EK, Boswell CL, Dueffert LG, Slocumb N, Boeve BF, Silber MH, Olson EJ, Morgenthaler TI, Tippmann-Peikert M. Factors associated with injury in REM sleep behavior disorder. Sleep Med 2014; 15:1332-8. [PMID: 25194585 DOI: 10.1016/j.sleep.2014.06.002] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 05/21/2014] [Accepted: 06/05/2014] [Indexed: 11/28/2022]
Abstract
OBJECTIVE As factors associated with injury in rapid eye movement (REM) sleep behavior disorder (RBD) remain largely unknown, we aimed to identify such factors. METHODS We surveyed consecutive idiopathic (iRBD) or symptomatic RBD patients seen between 2008 and 2010 regarding RBD-related injuries. Associations between injuries and clinical variables were determined with odds ratios (OR) and multiple logistic regression analyses. The primary outcome variables were injury and injury severity. RESULTS Fifty-three patients (40%) responded. Median age was 69 years, and 35 (73.5%) were men. Twenty-eight (55%) had iRBD. Twenty-nine (55%) reported injury, with 37.8% to self and 16.7% to the bed partner. 11.3% had marked injuries requiring medical intervention or hospitalization, including two (4%) subdural hematomas. iRBD diagnosis (OR = 6.8, p = 0.016) and dream recall (OR = 7.5, p = 0.03) were associated with injury; and iRBD diagnosis was independently associated with injury and injury severity adjusting for age, gender, DEB frequency, and duration. Falls (p = 0.03) were also associated with injury severity. DEB frequency was not associated with injury, injury severity, or falls. CONCLUSIONS Injuries appear to be a frequent complication of RBD, although the relatively low response rate in our survey could have biased results. iRBD patients are more likely to suffer injury--and more severe injuries--than symptomatic RBD patients. In addition, recall of dreams was also associated with injury, and dream enactment behavior (DEB)-related falls were associated with more severe injuries. One in nine patients suffered injury requiring medical intervention. The frequency of DEB did not predict RBD-related injuries, highlighting the importance of timely initiation of treatment for RBD in patients having even rare DEB episodes. Future prospective studies will be necessary to define predictors of injury in RBD.
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Affiliation(s)
- Stuart J McCarter
- Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Erik K St Louis
- Mayo Center for Sleep Medicine, Departments of Medicine and Neurology, Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA.
| | - Christopher L Boswell
- Department of Family Medicine, Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Lucas G Dueffert
- Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Nancy Slocumb
- Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Bradley F Boeve
- Mayo Center for Sleep Medicine, Department of Neurology, Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Michael H Silber
- Mayo Center for Sleep Medicine, Department of Neurology, Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Eric J Olson
- Mayo Center for Sleep Medicine, Departments of Medicine and Pulmonary & Critical Care Medicine, Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Timothy I Morgenthaler
- Mayo Center for Sleep Medicine, Departments of Medicine and Pulmonary & Critical Care Medicine, Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
| | - Maja Tippmann-Peikert
- Mayo Center for Sleep Medicine, Departments of Medicine and Neurology, Mayo Clinic College of Medicine, 200 First Street Southwest, Rochester, MN 55905, USA
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Sleep/wake problems in Parkinson’s disease: pathophysiology and clinicopathologic correlations. J Neural Transm (Vienna) 2014; 121 Suppl 1:S3-13. [DOI: 10.1007/s00702-014-1239-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2014] [Accepted: 05/06/2014] [Indexed: 11/25/2022]
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Muntean ML, Sixel-Döring F, Trenkwalder C. REM sleep behavior disorder in Parkinson's disease. J Neural Transm (Vienna) 2014; 121:41-47. [PMID: 24658661 DOI: 10.1007/s00702-014-1192-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 03/08/2014] [Indexed: 11/28/2022]
Abstract
Rapid eye movement (REM) sleep behavior disorder (RBD) is a sleep disorder characterized by loss of normal muscle atonia during REM sleep with recurrent dream enactment and excessive motor activity. It is a frequent feature in patients with Parkinson's disease (PD) and other alpha-synucleinopathies, and can occur at any stage of the disease. RBD could be considered a premotor clinical manifestation, and can antedate by many years the motor symptomatology. The prognostic value of RBD for the risk of developing PD still needs to be established. This review article focuses on the clinical aspects, screening and diagnostic criteria as well as therapeutic aspects of RBD in PD patients. Pathophysiological pathways are also briefly reviewed.
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Chen MC, Yu H, Huang ZL, Lu J. Rapid eye movement sleep behavior disorder. Curr Opin Neurobiol 2013; 23:793-8. [PMID: 23518139 PMCID: PMC3750096 DOI: 10.1016/j.conb.2013.02.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2013] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 11/15/2022]
Abstract
Rapid eye movement (REM) sleep behavior disorder (RBD) is a failure of the circuitry regulating motor atonia during REM sleep. In REM sleep, neurons of the sublaterodorsal tegmental nucleus (SLD) project to interneurons in the ventromedial medulla (VMM) and spinal cord that in turn inhibit spinal motoneurons. In RBD, degeneration of this circuitry disinhibits phasic motor commands originating from motor generators. The resulting behavior ranges from simple twitches or jerks to complex behavior. Simple behaviors in RBD may originate from cortical, brainstem and spinal cord motor generators, while complex behavior may originate from cortical motor generators, possibly related to dream content in REM sleep. While RBD can occur idiopathically, it is usually comorbid with or a precursor to a synucleinopathy such as Parkinson's disease (PD). RBD can precede the onset of PD by decades, suggesting an underlying pathology that can progressively afflict REM atonia and midbrain dopaminergic centers. The relative recovery of motor function during REM sleep in some of the cases of PD with RBD emphasizes the complexity of motor pathway control during wakefulness and REM sleep.
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Affiliation(s)
- Michael C Chen
- Department of Neurology, Beth Israel Deaconess Medical Center and Harvard Medical School, Boston, MA 02215, USA
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