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Videnovic A, Noble C, Reid KJ, Peng J, Turek FW, Marconi A, Rademaker AW, Simuni T, Zadikoff C, Zee PC. Circadian melatonin rhythm and excessive daytime sleepiness in Parkinson disease. JAMA Neurol 2014; 71:463-9. [PMID: 24566763 DOI: 10.1001/jamaneurol.2013.6239] [Citation(s) in RCA: 238] [Impact Index Per Article: 23.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
IMPORTANCE Diurnal fluctuations of motor and nonmotor symptoms and a high prevalence of sleep-wake disturbances in Parkinson disease (PD) suggest a role of the circadian system in the modulation of these symptoms. However, surprisingly little is known regarding circadian function in PD and whether circadian dysfunction is involved in the development of sleep-wake disturbances in PD. OBJECTIVE To determine the relationship between the timing and amplitude of the 24-hour melatonin rhythm, a marker of endogenous circadian rhythmicity, with self-reported sleep quality, the severity of daytime sleepiness, and disease metrics. DESIGN, SETTING, AND PARTICIPANTS A cross-sectional study from January 1, 2009, through December 31, 2012, of 20 patients with PD receiving stable dopaminergic therapy and 15 age-matched control participants. Both groups underwent blood sampling for the measurement of serum melatonin levels at 30-minute intervals for 24 hours under modified constant routine conditions at the Parkinson's Disease and Movement Disorders Center of Northwestern University. INTERVENTIONS Twenty-four hour monitoring of serum melatonin secretion. MAIN OUTCOMES AND MEASURES Clinical and demographic data, self-reported measures of sleep quality (Pittsburgh Sleep Quality Index) and daytime sleepiness (Epworth Sleepiness Scale), and circadian markers of the melatonin rhythm, including the amplitude, area under the curve (AUC), and phase of the 24-hour rhythm. RESULTS Patients with PD had blunted circadian rhythms of melatonin secretion compared with controls; the amplitude of the melatonin rhythm and the 24-hour AUC for circulating melatonin levels were significantly lower in PD patients (P < .001). Markers of the circadian phase were not significantly different between the 2 groups. Compared with PD patients without excessive daytime sleepiness, patients with excessive daytime sleepiness (Epworth Sleepiness Scale score ≥10) had a significantly lower amplitude of the melatonin rhythm and 24-hour melatonin AUC (P = .001). Disease duration, Unified Parkinson's Disease Rating Scale scores, levodopa equivalent dose, and global Pittsburgh Sleep Quality Index score in the PD group were not significantly related to measures of the melatonin circadian rhythm. CONCLUSIONS AND RELEVANCE Circadian dysfunction may underlie excessive sleepiness in PD. The nature of this association needs to be explored further in longitudinal studies. Approaches aimed to strengthen circadian function, such as timed exposure to bright light and exercise, might serve as complementary therapies for the nonmotor manifestations of PD.
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Affiliation(s)
- Aleksandar Videnovic
- Neurological Clinical Research Institute, Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts2Department of Neurology, Northwestern University, Chicago, Illinois
| | - Charleston Noble
- Department of Neurology, Northwestern University, Chicago, Illinois3Department of Physics, Lund University, Lund, Sweden
| | - Kathryn J Reid
- Department of Neurology, Northwestern University, Chicago, Illinois
| | - Jie Peng
- Department of Preventive Medicine, Northwestern University, Chicago, Illinois
| | - Fred W Turek
- Department of Neurobiology, Northwestern University, Chicago, Illinois
| | - Angelica Marconi
- Department of Neurology, Northwestern University, Chicago, Illinois
| | - Alfred W Rademaker
- Department of Preventive Medicine, Northwestern University, Chicago, Illinois
| | - Tanya Simuni
- Department of Neurology, Northwestern University, Chicago, Illinois
| | - Cindy Zadikoff
- Department of Neurology, Northwestern University, Chicago, Illinois
| | - Phyllis C Zee
- Department of Neurology, Northwestern University, Chicago, Illinois
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202
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Diederich NJ, Stebbins G, Schiltz C, Goetz CG. Are patients with Parkinson's disease blind to blindsight? Brain 2014; 137:1838-49. [PMID: 24764573 PMCID: PMC4032103 DOI: 10.1093/brain/awu094] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2013] [Revised: 02/08/2014] [Accepted: 03/15/2014] [Indexed: 12/22/2022] Open
Abstract
In Parkinson's disease, visual dysfunction is prominent. Visual hallucinations can be a major hallmark of late stage disease, but numerous visual deficits also occur in early stage Parkinson's disease. Specific retinopathy, deficits in the primary visual pathway and the secondary ventral and dorsal pathways, as well as dysfunction of the attention pathways have all been posited as causes of hallucinations in Parkinson's disease. We present data from patients with Parkinson's disease that contrast with a known neuro-ophthalmological syndrome, termed 'blindsight'. In this syndrome, there is an absence of conscious object identification, but preserved 'guess' of the location of a stimulus, preserved reflexive saccades and motion perception and preserved autonomical and expressive reactions to negative emotional facial expressions. We propose that patients with Parkinson's disease have the converse of blindsight, being 'blind to blindsight'. As such they preserve conscious vision, but show erroneous 'guess' localization of visual stimuli, poor saccades and motion perception, and poor emotional face perception with blunted autonomic reaction. Although a large data set on these deficits in Parkinson's disease has been accumulated, consolidation into one specific syndrome has not been proposed. Focusing on neuropathological and physiological data from two phylogenetically old and subconscious pathways, the retino-colliculo-thalamo-amygdala and the retino-geniculo-extrastriate pathways, we propose that aberrant function of these systems, including pathologically inhibited superior colliculus activity, deficient corollary discharges to the frontal eye fields, dysfunctional pulvinar, claustrum and amygdaloid subnuclei of the amygdala, the latter progressively burdened with Lewy bodies, underlie this syndrome. These network impairments are further corroborated by the concept of the 'silent amygdala'. Functionally being 'blind to blindsight' may facilitate the highly distinctive 'presence' or 'passage' hallucinations of Parkinson's disease and can help to explain handicaps in driving capacities and dysfunctional 'theory of mind'. We propose this synthesis to prompt refined neuropathological and neuroimaging studies on the pivotal nuclei in these pathways in order to better understand the networks underpinning this newly conceptualized syndrome in Parkinson's disease.
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Affiliation(s)
- Nico J Diederich
- 1 Department of Neurosciences, Centre Hospitalier de Luxembourg, Luxembourg-City, Luxembourg2 Centre for Systems Biomedicine, University of Luxembourg, Esch-Belval, Luxembourg3 Department of Neurological Sciences, Rush University Medical Centre, Chicago, USA
| | - Glenn Stebbins
- 3 Department of Neurological Sciences, Rush University Medical Centre, Chicago, USA
| | - Christine Schiltz
- 4 Institute of Cognitive Science and Assessment, Research Unit Education, Culture, Cognition and Society, University of Luxembourg, Luxembourg-City, Luxembourg
| | - Christopher G Goetz
- 3 Department of Neurological Sciences, Rush University Medical Centre, Chicago, USA
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203
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Sun L, Zhang H, Gu Z, Cao M, Li D, Chan P. Stereopsis impairment is associated with decreased color perception and worse motor performance in Parkinson's disease. Eur J Med Res 2014; 19:29. [PMID: 24886673 PMCID: PMC4046158 DOI: 10.1186/2047-783x-19-29] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Accepted: 04/24/2014] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND We conducted this study is to investigate the correlation between stereopsis dysfunction and color perception, as well as whether stereopsis impairment is associated with motor dysfunction in patients with Parkinson's disease (PD). METHOD Our present study included 45 PD patients and 50 non-PD control patients attending the Movement Disorder Center at Xuanwu Hospital Capital Medical University in Beijing from July 2011 to November 2011. Neurologic evaluations and visual function assessments were conducted, and the results between two groups of patients were compared. RESULTS We found that the total error scores (TESs) and partial error scores (PESs) for red, green, blue and purple were all significantly higher in PD patients than in control patients. The limited grade on the FLY Stereo Acuity Test with LEA Symbols was significantly lower in PD patients than in control patients (P = 0.0001), whereas the percentage of abnormal stereopsis in PD patients was significantly higher than in control patients (42.2% vs. 12%; P = 0.001). Multiple linear regression analysis showed that PD patients with higher Hoehn and Yahr Scale stage, and those with decreased stereopsis had higher Unified Parkinson's Disease Rating Scale (UPDRS) motor scores and worse motor function. Furthermore, our study demonstrates that the UPDRS motor scores and total average number of the Purdue Pegboard Test scores of PD patients were significantly improved when they had taken their medications, and the TESs and PESs for green were lower in when they were off their medications. CONCLUSION Our results provide more information on the underlying mechanisms of vision, motor and stereopsis impairments in PD patients.
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Affiliation(s)
- Liang Sun
- Department of Neurology, Xuanwu Hospital of Capital Medical University, 45 Changchun Street, Beijing 100053, China.
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204
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Roth NM, Saidha S, Zimmermann H, Brandt AU, Isensee J, Benkhellouf-Rutkowska A, Dornauer M, Kühn AA, Müller T, Calabresi PA, Paul F. Photoreceptor layer thinning in idiopathic Parkinson's disease. Mov Disord 2014; 29:1163-70. [DOI: 10.1002/mds.25896] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 02/20/2014] [Accepted: 03/03/2014] [Indexed: 11/09/2022] Open
Affiliation(s)
- Nicolas M. Roth
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | - Shiv Saidha
- Department of Neurology; Beaumont University Hospital; Republic of Ireland
- Department of Neurology; John Hopkins School of Medicine; Baltimore Maryland USA
| | - Hanna Zimmermann
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | - Alexander U. Brandt
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | - Justine Isensee
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | | | - Matthias Dornauer
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
| | - Andrea A. Kühn
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
- Department of Neurology; Charité-Universitätsmedizin Berlin; Germany
| | - Thomas Müller
- Department of Neurology; St. Joseph Hospital; Berlin Germany
| | - Peter A. Calabresi
- Department of Neurology; John Hopkins School of Medicine; Baltimore Maryland USA
| | - Friedemann Paul
- NeuroCure Clinical Research Center; Charité-Universitätsmedizin Berlin; Germany
- Department of Neurology; Charité-Universitätsmedizin Berlin; Germany
- Experimental and Clinical Research Center; Charité-Universitätsmedizin Berlin and Max-Delbrück-Center for Molecular Medicine; Berlin Germany
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205
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Popova E. Role of dopamine in distal retina. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:333-58. [PMID: 24728309 DOI: 10.1007/s00359-014-0906-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/24/2014] [Accepted: 03/25/2014] [Indexed: 01/11/2023]
Abstract
Dopamine is the most abundant catecholamine in the vertebrate retina. Despite the description of retinal dopaminergic cells three decades ago, many aspects of their function in the retina remain unclear. There is no consensus among the authors about the stimulus conditions for dopamine release (darkness, steady or flickering light) as well as about its action upon the various types of retinal cells. Many contradictory results exist concerning the dopamine effect on the gross electrical activity of the retina [reflected in electroretinogram (ERG)] and the receptors involved in its action. This review summarized current knowledge about the types of the dopaminergic neurons and receptors in the retina as well as the effects of dopamine receptor agonists and antagonists on the light responses of photoreceptors, horizontal and bipolar cells in both nonmammalian and mammalian retina. Special focus of interest concerns their effects upon the diffuse ERG as a useful tool for assessment of the overall function of the distal retina. An attempt is made to reveal some differences between the dopamine actions upon the activity of the ON versus OFF channel in the distal retina. The author has included her own results demonstrating such differences.
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Affiliation(s)
- E Popova
- Department of Physiology, Medical Faculty, Medical University, 1431, Sofia, Bulgaria,
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206
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Afsari F, Christensen KV, Smith GP, Hentzer M, Nippe OM, Elliott CJH, Wade AR. Abnormal visual gain control in a Parkinson's disease model. Hum Mol Genet 2014; 23:4465-78. [PMID: 24718285 PMCID: PMC4119403 DOI: 10.1093/hmg/ddu159] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Our understanding of Parkinson's disease (PD) has been revolutionized by the discovery of disease-causing genetic mutations. The most common of these is the G2019S mutation in the LRRK2 kinase gene, which leads to increased kinase activity. However, the link between increased kinase activity and PD is unclear. Previously, we showed that dopaminergic expression of the human LRRK2-G2019S transgene in flies led to an activity-dependent loss of vision in older animals and we hypothesized that this may have been preceded by a failure to regulate neuronal activity correctly in younger animals. To test this hypothesis, we used a sensitive measure of visual function based on frequency-tagged steady-state visually evoked potentials. Spectral analysis allowed us to identify signals from multiple levels of the fly visual system and wild-type visual response curves were qualitatively similar to those from human cortex. Dopaminergic expression of hLRRK2-G2019S increased contrast sensitivity throughout the retinal network. To test whether this was due to increased kinase activity, we fed Drosophila with kinase inhibitors targeted at LRRK2. Contrast sensitivity in both day 1 and day 14 flies was normalized by a novel LRRK2 kinase inhibitor ‘BMPPB-32’. Biochemical and cellular assays suggested that BMPPB-32 would be a more specific kinase inhibitor than LRRK2-IN-1. We confirmed this in vivo, finding that dLRRK− null flies show large off-target effects with LRRK2-IN-1 but not BMPPB-32. Our data link the increased Kinase activity of the G2019S-LRRK2 mutation to neuronal dysfunction and demonstrate the power of the Drosophila visual system in assaying the neurological effects of genetic diseases and therapies.
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Affiliation(s)
| | - Kenneth V Christensen
- Neuroscience Drug Discovery DK, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark
| | - Garrick Paul Smith
- Neuroscience Drug Discovery DK, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark
| | - Morten Hentzer
- Neuroscience Drug Discovery DK, H. Lundbeck A/S, Ottiliavej 9, DK-2500 Valby, Denmark
| | | | | | - Alex R Wade
- Department of Psychology, University of York, YO1 5DD York, UK
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207
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Pescosolido N, Stefanucci A, Buomprisco G, Fazio S. Amblyopia treatment strategies and new drug therapies. J Pediatr Ophthalmol Strabismus 2014; 51:78-86. [PMID: 24410693 DOI: 10.3928/01913913-20130107-01] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/10/2013] [Accepted: 10/09/2013] [Indexed: 11/20/2022]
Abstract
Amblyopia is a unilateral or bilateral reduction of visual acuity secondary to abnormal visual experience during early childhood. It is one of the most common causes of vision loss and monocular blindness and is commonly associated with strabismus, anisometropia, and visual deprivation (in particular congenital cataract and ptosis). It is clinically defined as a two-line difference of best-corrected visual acuity between the eyes. The purpose of this study was to understand the neural mechanisms of amblyopia and summarize the current therapeutic strategies. In particular, the authors focused on the concept of brain plasticity and its implication for new treatment strategies for children and adults with amblyopia.
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208
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Ong YL, Ong YT, Ikram MK, Chen CLH, Wong TY. Potential Applications of Spectral-Domain Optical Coherence Tomography (SD-OCT) in the Study of Alzheimer's Disease. PROCEEDINGS OF SINGAPORE HEALTHCARE 2014. [DOI: 10.1177/201010581402300112] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Alzheimer's Disease (AD) is the most common subtype of dementia. As the prevalence of dementia is projected to increase, the burden of the disease on society is expected to become increasingly significant. The link between eye pathology and neurodegenerative diseases has been established in multiple studies. In particular, optic nerve parameters associated with neuronal loss in AD include retinal ganglion cells (RGC). Retinal ganglion cells are similar to neurons in the cerebral cortex, and have been correlated to neurodegeneration in AD. Ocular imaging techniques such as optical coherence tomography (OCT) have provided a rapid and non-invasive method for quantifying optic nerve parameters in vivo. Spectral domain (SD)-OCT has shown good potential in the study of the optic nerve in AD as it enables more comprehensive assessment of RGCs. Earlier generation OCT techniques only assess the retinal nerve fibre layer, which consists of RGC axons. Spectral domain-OCT offers ultra-high scan speed and image resolution, enabling improved sampling of retinal layers. Retinal layers such as the ganglion cell-inner plexiform layer (GC-IPL), which contain the dendrites and nuclei of RGCs, can be assessed with SD-OCT. This article presents a review of literature associating eye pathology with AD, and explores the potential of SD-OCT in future AD studies. Spectral domain-OCT has the potential to draw more links between optic nerve pathology and neurodegeneration.
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Affiliation(s)
- Yi-Lin Ong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
| | - Yi-Ting Ong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Mohammad Kamran Ikram
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Memory Ageing and Cognition Centre, National University Health System, Singapore
| | | | - Tien Yin Wong
- Singapore Eye Research Institute, Singapore National Eye Centre, Singapore
- Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
- Office of Clinical Sciences, Duke-NUS Graduate Medical School, Singapore
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209
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Garcia-Martin E, Larrosa JM, Polo V, Satue M, Marques ML, Alarcia R, Seral M, Fuertes I, Otin S, Pablo LE. Distribution of retinal layer atrophy in patients with Parkinson disease and association with disease severity and duration. Am J Ophthalmol 2014; 157:470-478.e2. [PMID: 24315296 DOI: 10.1016/j.ajo.2013.09.028] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/28/2013] [Accepted: 09/30/2013] [Indexed: 11/26/2022]
Abstract
PURPOSE To evaluate the thickness of the 10 retinal layers in the paramacular area of Parkinson disease patients using a new segmentation technology of optical coherence tomography (OCT) to examine whether the thickness of specific layers predicts neurodegeneration or Parkinson disease severity. DESIGN Observational prospective study. METHODS Parkinson disease patients (n = 129) and age-matched healthy subjects (n = 129) were enrolled. The Spectralis OCT system was used to automatically segment all retinal layers in a parafoveal scan using the new segmentation application prototype. Mean thickness of each layer was calculated and compared between Parkinson disease patients and healthy subjects, and between Parkinson disease patients with disease durations of less than or at least 10 years. A correlation analysis was performed to evaluate the association between retinal layer thickness, duration of disease, and Parkinson disease severity. Logistic regression analysis was performed to determine the most sensitive layer for predicting axonal atrophy. RESULTS Parkinson disease patients showed statistically significant reduced thickness in the retinal nerve fiber, ganglion cell, inner plexiform, and outer plexiform layers and increased thickness in the inner nuclear layer compared with healthy subjects (P < .05). The inner retinal layers were more affected in Parkinson disease patients with long disease duration. The ganglion cell layer thickness was inversely correlated with disease duration and Parkinson disease severity, and was predictive of axonal damage in Parkinson disease patients. CONCLUSIONS The segmentation application of the Spectralis OCT revealed retinal layer atrophy in Parkinson disease patients, especially in the inner layers of patients with long disease duration. Ganglion cell layer reduction was associated with increased axonal damage.
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210
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Willis GL, Moore C, Armstrong SM. Parkinson's disease, lights and melanocytes: looking beyond the retina. Sci Rep 2014; 4:3921. [PMID: 24473093 PMCID: PMC5379242 DOI: 10.1038/srep03921] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 01/13/2014] [Indexed: 12/11/2022] Open
Abstract
Critical analysis of recent research suggesting that light pollution causes Parkinson's disease (PD) reveals that such a hypothesis is unsustainable in the context of therapeutic use of light in treating various neuropsychiatric conditions. Reinterpretation of their findings suggests that retinal damage caused by prolonged light exposure may have contributed to the observed enhancement of experimental PD. To test this hypothesis further, forty-two Sprague Dawley rats received microinjections of 6-hydroxydopamine (6-OHDA), 1-methyl-4-phenyl-2, 4, 6-tetrahydropyridine (MPTP), paraquat or rotenone into the vitreal mass in doses so minute that the effects could not be attributed to diffusion into brain. Significant changes in five motor parameters consistent with symptoms of experimental PD were observed. These findings support the interpretation that the retina is involved in the control of motor function and in the aetiology of PD.
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Affiliation(s)
- Gregory L. Willis
- Neurosciences Section, The Bronowski Institute of Behavioural Neuroscience, Coliban Medical Centre, 19 Jennings Street, Kyneton, Victoria 3444, Australia
| | - Cleo Moore
- Neurosciences Section, The Bronowski Institute of Behavioural Neuroscience, Coliban Medical Centre, 19 Jennings Street, Kyneton, Victoria 3444, Australia
| | - Stuart Maxwell Armstrong
- Neurosciences Section, The Bronowski Institute of Behavioural Neuroscience, Coliban Medical Centre, 19 Jennings Street, Kyneton, Victoria 3444, Australia
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211
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Goldman JG, Stebbins GT, Dinh V, Bernard B, Merkitch D, deToledo-Morrell L, Goetz CG. Visuoperceptive region atrophy independent of cognitive status in patients with Parkinson's disease with hallucinations. ACTA ACUST UNITED AC 2014; 137:849-59. [PMID: 24480486 DOI: 10.1093/brain/awt360] [Citation(s) in RCA: 115] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Visual hallucinations are frequent, disabling complications of advanced Parkinson's disease, but their neuroanatomical basis is incompletely understood. Previous structural brain magnetic resonance imaging studies suggest volume loss in the mesial temporal lobe and limbic regions in subjects with Parkinson's disease with visual hallucinations, relative to those without visual hallucinations. However, these studies have not always controlled for the presence of cognitive impairment or dementia, which are common co-morbidities of hallucinations in Parkinson's disease and whose neuroanatomical substrates may involve mesial temporal lobe and limbic regions. Therefore, we used structural magnetic resonance imaging to examine grey matter atrophy patterns associated with visual hallucinations, comparing Parkinson's disease hallucinators to Parkinson's disease non-hallucinators of comparable cognitive function. We studied 50 subjects with Parkinson's disease: 25 classified as current and chronic visual hallucinators and 25 as non-hallucinators, who were matched for cognitive status (demented or non-demented) and age (± 3 years). Subjects underwent (i) clinical evaluations; and (ii) brain MRI scans analysed using whole-brain voxel-based morphometry techniques. Clinically, the Parkinson's disease hallucinators did not differ in their cognitive classification or performance in any of the five assessed cognitive domains, compared with the non-hallucinators. The Parkinson's disease groups also did not differ significantly in age, motor severity, medication use or duration of disease. On imaging analyses, the hallucinators, all of whom experienced visual hallucinations, exhibited grey matter atrophy with significant voxel-wise differences in the cuneus, lingual and fusiform gyri, middle occipital lobe, inferior parietal lobule, and also cingulate, paracentral, and precentral gyri, compared with the non-hallucinators. Grey matter atrophy in the hallucinators occurred predominantly in brain regions responsible for processing visuoperceptual information including the ventral 'what' and dorsal 'where' pathways, which are important in object and facial recognition and identification of spatial locations of objects, respectively. Furthermore, the structural brain changes seen on magnetic resonance imaging occurred independently of cognitive function and age. Our findings suggest that when hallucinators and non-hallucinators are similar in their cognitive performance, the neural networks involving visuoperceptual pathways, rather than the mesial temporal lobe regions, distinctively contribute to the pathophysiology of visual hallucinations and may explain their predominantly visual nature in Parkinson's disease. Identification of distinct structural MRI differences associated with hallucinations in Parkinson's disease may permit earlier detection of at-risk patients and ultimately, development of therapies specifically targeting hallucinations and visuoperceptive functions.
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Affiliation(s)
- Jennifer G Goldman
- 1 Rush University Medical Center, Department of Neurological Sciences, Chicago, IL, USA
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213
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Stuart S, Alcock L, Galna B, Lord S, Rochester L. The measurement of visual sampling during real-world activity in Parkinson's disease and healthy controls: a structured literature review. J Neurosci Methods 2013; 222:175-88. [PMID: 24291711 DOI: 10.1016/j.jneumeth.2013.11.018] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 11/18/2013] [Accepted: 11/19/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Visual sampling techniques are used to investigate the complex role of vision during real-world activities in Parkinson's disease. Earlier research is limited to static simple tasks or measurement of eye movements alone, but more recent investigations involve more real-world activities. The approach to the objective measurement of eye movements varies with respect to instrumentation, testing protocols, and mediating factors that may influence visual sampling. OBJECTIVES The aim of this review was to examine previous work measuring visual sampling during real-world activities in Parkinson's disease to inform the development of robust protocols. Within this review a real-world activity was considered to be a goal-orientated motor task involving more than one body segment such as reaching or walking. METHODS Medline, Embase, PsychInfo, Scopus, Web of Knowledge, PubMed and the Cochrane library databases were searched. Two independent reviewers and an adjudicator screened articles that described quantitative visual sampling in people with Parkinson's disease and healthy controls. RESULTS Twenty full-text articles were screened and 15 met inclusion/exclusion criteria. A wide range of instruments and outcome measures were reported which were generally used in a task-dependent manner. Instrument reliability and validity was insufficiently reported in all studies. Few studies considered mediators of visual sampling such as visual or cognitive deficits. CONCLUSIONS Future research is required to accurately characterise visual impairments in Parkinson's disease and during real-world activities. Composite use of instruments may be required to achieve reliability and validity of visual sampling outcomes which need to be standardised. Recommendations also include assessment of cognition and basic visual function.
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Affiliation(s)
- Samuel Stuart
- Institute for Ageing and Health, Clinical Ageing Research Unit, Newcastle University, United Kingdom
| | - Lisa Alcock
- Institute for Ageing and Health, Clinical Ageing Research Unit, Newcastle University, United Kingdom
| | - Brook Galna
- Institute for Ageing and Health, Clinical Ageing Research Unit, Newcastle University, United Kingdom
| | - Sue Lord
- Institute for Ageing and Health, Clinical Ageing Research Unit, Newcastle University, United Kingdom
| | - Lynn Rochester
- Institute for Ageing and Health, Clinical Ageing Research Unit, Newcastle University, United Kingdom.
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Lack of association of morphologic and functional retinal changes with motor and non-motor symptoms severity in Parkinson’s disease. J Neural Transm (Vienna) 2013; 121:139-45. [DOI: 10.1007/s00702-013-1093-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 09/05/2013] [Indexed: 10/26/2022]
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216
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Giorelli M, Bagnoli J, Consiglio L, Lopane M, Zimatore GB, Zizza D, Difazio P. Do non-motor symptoms in Parkinson's disease differ from essential tremor before initial diagnosis? A clinical and scintigraphic study. Parkinsonism Relat Disord 2013; 20:17-21. [PMID: 24080307 DOI: 10.1016/j.parkreldis.2013.09.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2013] [Revised: 08/19/2013] [Accepted: 09/03/2013] [Indexed: 10/26/2022]
Abstract
BACKGROUND Non-motor symptoms (NMS) in Parkinson's disease (PD) are common, increase the patients' disability and have a significantly negative impact on their quality of life. Essential tremor (ET) is also affected by non-motor symptoms and often enters into the differential diagnosis with PD. Brain scintigraphy with [(123)I]β-CIT SPECT is a technique used to facilitate differential diagnosis between PD and ET. METHODS We evaluated both motor impairment (MDS-UPDRS-III) and non-motor symptoms (NMSQuest) in patients who underwent a [(123)I]β-CIT SPECT examination for diagnostic purposes. Both the clinical and the scintigraphic data obtained from the selected PD (n = 31) and ET (n = 22) patients were compared. RESULTS We did not detect a significant difference in the total number of NMS reported by either PD (10.4 ± 4.9) or ET patients (8.41 ± 3.3). PD patients reported more drooling (29%), hyposmia (32.2%), hallucinations (19.3%), difficulty in concentrating (51.6%), orthostatic dizziness (67.7%), falling (19.3%), vivid dreams (32.2%), REM sleep behavior disorder (58%), and diplopia (22.5%) compared with ET patients. PD patients who complained of drooling, orthostatic dizziness, and diplopia had greater denervation of the caudata than did the PD patients who did not report the same symptoms. The differences observed were not associated with differences in age, sex, UPDRS-III score, and the presence/absence of tremor. CONCLUSIONS The declaration of non-motor symptoms is influenced by subjective factors that are widely suggestible. When analyzed early and before receiving a definitive diagnosis, PD patients complain of specific symptoms that seem to depend on different pathogenetic mechanisms.
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Affiliation(s)
- Maurizio Giorelli
- Operative Unit of Neurology, "Dimiccoli" General Hospital, Barletta, Italy.
| | - Junia Bagnoli
- Operative Unit of Nuclear Medicine, "Dimiccoli" General Hospital, Barletta, Italy
| | - Luigi Consiglio
- Operative Unit of Nuclear Medicine, "Dimiccoli" General Hospital, Barletta, Italy
| | - Marialuisa Lopane
- Operative Unit of Nuclear Medicine, "Dimiccoli" General Hospital, Barletta, Italy
| | | | - Daniela Zizza
- Operative Unit of Nuclear Medicine, "Dimiccoli" General Hospital, Barletta, Italy
| | - Pasquale Difazio
- Operative Unit of Nuclear Medicine, "Dimiccoli" General Hospital, Barletta, Italy
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Alterations in energy metabolism, neuroprotection and visual signal transduction in the retina of Parkinsonian, MPTP-treated monkeys. PLoS One 2013; 8:e74439. [PMID: 24040246 PMCID: PMC3764107 DOI: 10.1371/journal.pone.0074439] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 08/01/2013] [Indexed: 11/27/2022] Open
Abstract
Parkinson disease is mainly characterized by the degeneration of dopaminergic neurons in the central nervous system, including the retina. Different interrelated molecular mechanisms underlying Parkinson disease-associated neuronal death have been put forward in the brain, including oxidative stress and mitochondrial dysfunction. Systemic injection of the proneurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) to monkeys elicits the appearance of a parkinsonian syndrome, including morphological and functional impairments in the retina. However, the intracellular events leading to derangement of dopaminergic and other retinal neurons in MPTP-treated animal models have not been so far investigated. Here we have used a comparative proteomics approach to identify proteins differentially expressed in the retina of MPTP-treated monkeys. Proteins were solubilized from the neural retinas of control and MPTP-treated animals, labelled separately with two different cyanine fluorophores and run pairwise on 2D DIGE gels. Out of >700 protein spots resolved and quantified, 36 were found to exhibit statistically significant differences in their expression levels, of at least ±1.4-fold, in the parkinsonian monkey retina compared with controls. Most of these spots were excised from preparative 2D gels, trypsinized and subjected to MALDI-TOF MS and LC-MS/MS analyses. Data obtained were used for protein sequence database interrogation, and 15 different proteins were successfully identified, of which 13 were underexpressed and 2 overexpressed. These proteins were involved in key cellular functional pathways such as glycolysis and mitochondrial electron transport, neuronal protection against stress and survival, and phototransduction processes. These functional categories underscore that alterations in energy metabolism, neuroprotective mechanisms and signal transduction are involved in MPTP-induced neuronal degeneration in the retina, in similarity to mechanisms thought to underlie neuronal death in the Parkinson’s diseased brain and neurodegenerative diseases of the retina proper.
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218
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Stereopsis and extrastriate cortical atrophy in Parkinson's disease: a voxel-based morphometric study. Neuroreport 2013; 24:229-32. [PMID: 23376833 DOI: 10.1097/wnr.0b013e32835edbc5] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Among the various visuospatial dysfunctions, deficits of stereopsis could be associated with Parkinson's disease. We examined differences in regional gray matter volume between Parkinson's disease patients with normal stereopsis and with abnormal stereopsis to delineate the possible anatomical correlate of stereopsis. Stereopsis was assessed using the Titmus test in 35 drug-naive patients with Parkinson's disease. Voxel-based morphometry was utilized to assess regionally specific differences in gray matter volume between 16 patients with normal stereopsis and 19 patients with abnormal stereopsis. Patients with abnormal stereopsis had a significant gray matter volume reduction in the right extrastriate visual cortex compared with patients with normal stereopsis (P<0.05, corrected for multiple comparisons). Voxel values extracted from the significant cluster in group comparison were negatively correlated with log seconds of arc of the Titmus test (Spearman correlation, P<0.001). Our results suggest that deficits of stereopsis are associated with nondominant extrastriate cortical atrophy and that abnormal stereopsis implicates the cortical visual dysfunction as part of the nonmotor symptoms in Parkinson's disease.
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Abstract
Dopaminergic neuronal cells have been identified in the inner nuclear and inner plexiform layers of the human retina. The dopaminergic content of the retina is reduced in patients with idiopathic Parkinson disease (PD). These observations led us to study the retinal nerve fiber layer (RNFL) thickness in patients with PD without visual impairment compared to healthy controls using spectral-domain optical coherence tomography (SD-OCT). Eighty-two subjects, including 42 patients with PD, newly diagnosed and untreated (24 men, 18 women, age range: 47-66 years), and 40 healthy controls, were enrolled. Both eyes of patients with PD and controls were imaged with SD-OCT. The mean RNFL thickness was 77 ± 11.5 μm in PD patients and 89 ± 8.7 μm in healthy controls (P = 0.001). Selective thinning of the RNFL was found in the temporal region with mean temporal RNFL thickness of 66 ± 6.7 μm in PD patients and 75 ± 4.8 μm in controls (P = 0.001). The thickness of the RNFL is decreased in PD patients. Demonstrating progressive thinning of RNFL over time will be critical for validating optical coherence tomography as a viable biomarker of patients with PD.
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220
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Schneider M, Müller HP, Lauda F, Tumani H, Ludolph AC, Kassubek J, Pinkhardt EH. Retinal single-layer analysis in Parkinsonian syndromes: an optical coherence tomography study. J Neural Transm (Vienna) 2013; 121:41-7. [DOI: 10.1007/s00702-013-1072-3] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Accepted: 07/19/2013] [Indexed: 01/02/2023]
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Maresca A, la Morgia C, Caporali L, Valentino ML, Carelli V. The optic nerve: a "mito-window" on mitochondrial neurodegeneration. Mol Cell Neurosci 2013; 55:62-76. [PMID: 22960139 PMCID: PMC3629569 DOI: 10.1016/j.mcn.2012.08.004] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2012] [Revised: 07/27/2012] [Accepted: 08/06/2012] [Indexed: 01/16/2023] Open
Abstract
Retinal ganglion cells (RGCs) project their long axons, composing the optic nerve, to the brain, transmitting the visual information gathered by the retina, ultimately leading to formed vision in the visual cortex. The RGC cellular system, representing the anterior part of the visual pathway, is vulnerable to mitochondrial dysfunction and optic atrophy is a very frequent feature of mitochondrial and neurodegenerative diseases. The start of the molecular era of mitochondrial medicine, the year 1988, was marked by the identification of a maternally inherited form of optic atrophy, Leber's hereditary optic neuropathy, as the first disease due to mitochondrial DNA point mutations. The field of mitochondrial medicine has expanded enormously over the last two decades and many neurodegenerative diseases are now known to have a primary mitochondrial etiology or mitochondrial dysfunction plays a relevant role in their pathogenic mechanism. Recent technical advancements in neuro-ophthalmology, such as optical coherence tomography, prompted a still ongoing systematic re-investigation of retinal and optic nerve involvement in neurodegenerative disorders. In addition to inherited optic neuropathies, such as Leber's hereditary optic neuropathy and dominant optic atrophy, and in addition to the syndromic mitochondrial encephalomyopathies or mitochondrial neurodegenerative disorders such as some spinocerebellar ataxias or familial spastic paraparesis and other disorders, we draw attention to the involvement of the optic nerve in classic age-related neurodegenerative disorders such as Parkinson and Alzheimer disease. We here provide an overview of optic nerve pathology in these different clinical settings, and we review the possible mechanisms involved in the pathogenesis of optic atrophy. This may be a model of general value for the field of neurodegeneration. This article is part of a Special Issue entitled 'Mitochondrial function and dysfunction in neurodegeneration'.
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Affiliation(s)
| | | | | | | | - Valerio Carelli
- Corresponding author at: IRCCS Institute of Neurological Sciences of Bologna, Department of Neurological Sciences, University of Bologna, Via Ugo Foscolo 7, 40123 Bologna, Italy. Fax: + 39 051 2092751.
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Hindle S, Afsari F, Stark M, Middleton CA, Evans GJ, Sweeney ST, Elliott CJ. Dopaminergic expression of the Parkinsonian gene LRRK2-G2019S leads to non-autonomous visual neurodegeneration, accelerated by increased neural demands for energy. Hum Mol Genet 2013; 22:2129-40. [PMID: 23396536 PMCID: PMC3652415 DOI: 10.1093/hmg/ddt061] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2012] [Accepted: 02/05/2013] [Indexed: 12/31/2022] Open
Abstract
Parkinson's disease (PD) is associated with loss of dopaminergic signalling, and affects not just movement, but also vision. As both mammalian and fly visual systems contain dopaminergic neurons, we investigated the effect of LRRK2 mutations (the most common cause of inherited PD) on Drosophila electroretinograms (ERGs). We reveal progressive loss of photoreceptor function in flies expressing LRRK2-G2019S in dopaminergic neurons. The photoreceptors showed elevated autophagy, apoptosis and mitochondrial disorganization. Head sections confirmed extensive neurodegeneration throughout the visual system, including regions not directly innervated by dopaminergic neurons. Other PD-related mutations did not affect photoreceptor function, and no loss of vision was seen with kinase-dead transgenics. Manipulations of the level of Drosophila dLRRK suggest G2019S is acting as a gain-of-function, rather than dominant negative mutation. Increasing activity of the visual system, or of just the dopaminergic neurons, accelerated the G2019S-induced deterioration of vision. The fly visual system provides an excellent, tractable model of a non-autonomous deficit reminiscent of that seen in PD, and suggests that increased energy demand may contribute to the mechanism by which LRRK2-G2019S causes neurodegeneration.
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223
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Berg D, Lang AE, Postuma RB, Maetzler W, Deuschl G, Gasser T, Siderowf A, Schapira AH, Oertel W, Obeso JA, Olanow CW, Poewe W, Stern M. Changing the research criteria for the diagnosis of Parkinson's disease: obstacles and opportunities. Lancet Neurol 2013; 12:514-24. [DOI: 10.1016/s1474-4422(13)70047-4] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Khoo TK, Yarnall AJ, Duncan GW, Coleman S, O'Brien JT, Brooks DJ, Barker RA, Burn DJ. The spectrum of nonmotor symptoms in early Parkinson disease. Neurology 2013; 80:276-81. [PMID: 23319473 DOI: 10.1212/wnl.0b013e31827deb74] [Citation(s) in RCA: 289] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
OBJECTIVE Nonmotor symptoms (NMS) are common in patients with established Parkinson disease (PD) but their frequency in early PD has not been extensively studied. Our aim was to determine the frequency of NMS in a cohort of patients with newly diagnosed PD. METHODS A total of 159 patients with early PD and 99 healthy controls participated in this study. NMS were screened for using the nonmotor symptom questionnaire. Other assessments included measures of motor disability (Movement Disorders Society-revised unified Parkinson's disease rating scale [MDS-UPDRS]), disease severity (Hoehn & Yahr staging), depression (geriatric depression scale), and global cognitive function (Mini-mental state examination and Montreal cognitive assessment). RESULTS The PD group reported a significantly greater number of NMS compared with controls (8.4 [4.3] vs. 2.8 [2.6]). In the PD group, the most commonly experienced NMS were excessive saliva, forgetfulness, urinary urgency, hyposmia, and constipation. Patients with higher MDS-UPDRS III scores and those with the postural instability gait subtype experienced a greater number of NMS. CONCLUSION NMS are common in early PD and reflect the multisystem nature of the disorder. Even in the earliest stages of PD, NMS may be detrimental to patients' functional status and sense of well-being.
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Affiliation(s)
- Tien K Khoo
- Institute for Ageing and Health, Newcastle University, Newcastle upon Tyne, UK
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225
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Devos H, Vandenberghe W, Nieuwboer A, Tant M, De Weerdt W, Dawson JD, Uc EY. Validation of a screening battery to predict driving fitness in people with Parkinson's disease. Mov Disord 2013; 28:671-4. [DOI: 10.1002/mds.25387] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2012] [Revised: 12/21/2012] [Accepted: 01/10/2013] [Indexed: 11/08/2022] Open
Affiliation(s)
| | | | - Alice Nieuwboer
- Department of Rehabilitation Sciences; KU Leuven; Heverlee; Belgium
| | - Mark Tant
- Center for Evaluation of Fitness to Drive and Car Adaptations (CARA); Belgian Road Safety Institute; Brussels; Belgium
| | - Willy De Weerdt
- Department of Rehabilitation Sciences; KU Leuven; Heverlee; Belgium
| | - Jeffrey D. Dawson
- Department of Biostatistics; University of Iowa; Iowa City; Iowa; USA
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226
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Laudate TM, Neargarder S, Cronin-Golomb A. Line bisection in Parkinson's disease: investigation of contributions of visual field, retinal vision, and scanning patterns to visuospatial function. Behav Neurosci 2013; 127:151-63. [PMID: 23356329 DOI: 10.1037/a0031618] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Parkinson's disease (PD) is characterized by disorders of visuospatial function that can impact everyday functioning. Visuospatial difficulties are more prominent in those whose motor symptoms begin on the left body side (LPD) than the right body side (RPD) and have mainly been attributed to parietal dysfunction. The source of visuospatial dysfunction is unclear, as in addition to subcortical-cortical changes, there are irregularities of visual scanning and potentially of retinal-level vision in PD. To assess these potential contributors, performance on a visuospatial task--line bisection--was examined together with retinal structure (nerve fiber layer thickness, measured by optical coherence tomography [OCT]), retinal function (contrast sensitivity, measured by frequency-doubling technology [FDT]), and visual scanning patterns. Participants included 20 nondemented patients (10 LPD, 10 RPD) and 11 normal control (NC) adults. Relative to the other groups, LPD were expected to show rightward bias on horizontal line bisection, especially within the left visual hemispace, and downward bias on vertical bisection. LPD relative rightward bias was confirmed, though not mainly within the left hemispace and not correlated with retinal structure or function. Retinal thinning was seen in LPD relative to RPD. Qualitative visualization of eye movements suggested greater LPD exploration of the right than left side of the line during horizontal bisection, and some overall compression of scanning range in RPD (both orientations) and LPD (primarily vertical). Results indicated that rightward visuospatial bias in our LPD sample arose not from abnormalities at the retinal level but potentially from attentional biases, reflected in eye movement patterns.
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Affiliation(s)
- Thomas M Laudate
- Department of Psychology, Boston University, 648 Beacon Street, Boston, MA 02215, USA
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227
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Campello L, Esteve-Rudd J, Cuenca N, Martín-Nieto J. The ubiquitin-proteasome system in retinal health and disease. Mol Neurobiol 2013; 47:790-810. [PMID: 23339020 DOI: 10.1007/s12035-012-8391-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2012] [Accepted: 12/18/2012] [Indexed: 10/27/2022]
Abstract
The ubiquitin-proteasome system (UPS) is the main intracellular pathway for modulated protein turnover, playing an important role in the maintenance of cellular homeostasis. It also exerts a protein quality control through degradation of oxidized, mutant, denatured, or misfolded proteins and is involved in many biological processes where protein level regulation is necessary. This system allows the cell to modulate its protein expression pattern in response to changing physiological conditions and provides a critical protective role in health and disease. Impairments of UPS function in the central nervous system (CNS) underlie an increasing number of genetic and idiopathic diseases, many of which affect the retina. Current knowledge on the UPS composition and function in this tissue, however, is scarce and dispersed. This review focuses on UPS elements reported in the retina, including ubiquitinating and deubiquitinating enzymes (DUBs), and alternative proteasome assemblies. Known and inferred roles of protein ubiquitination, and of the related, SUMO conjugation (SUMOylation) process, in normal retinal development and adult homeostasis are addressed, including modulation of the visual cycle and response to retinal stress and injury. Additionally, the relationship between UPS dysfunction and human neurodegenerative disorders affecting the retina, including Alzheimer's, Parkinson's, and Huntington's diseases, are dealt with, together with numerous instances of retina-specific illnesses with UPS involvement, such as retinitis pigmentosa, macular degenerations, glaucoma, diabetic retinopathy (DR), and aging-related impairments. This information, though still basic and limited, constitutes a suitable framework to be expanded in incoming years and should prove orientative toward future therapy design targeting sight-affecting diseases with a UPS underlying basis.
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Affiliation(s)
- Laura Campello
- Departamento de Fisiología, Genética y Microbiología, Facultad de Ciencias, Universidad de Alicante, 03080 Alicante, Spain
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228
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Foveal vision is impaired in Parkinson's disease. Parkinsonism Relat Disord 2013; 19:1-14. [DOI: 10.1016/j.parkreldis.2012.07.012] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2010] [Revised: 07/16/2012] [Accepted: 07/21/2012] [Indexed: 11/23/2022]
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229
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Gruber N, Mosimann UP, Müri RM, Nef T. Vision and night driving abilities of elderly drivers. TRAFFIC INJURY PREVENTION 2013; 14:477-485. [PMID: 23683029 DOI: 10.1080/15389588.2012.727510] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE In this article, we review the impact of vision on older people's night driving abilities. Driving is the preferred and primary mode of transport for older people. It is a complex activity where intact vision is seminal for road safety. Night driving requires mesopic rather than scotopic vision, because there is always some light available when driving at night. Scotopic refers to night vision, photopic refers to vision under well-lit conditions, and mesopic vision is a combination of photopic and scotopic vision in low but not quite dark lighting situations. With increasing age, mesopic vision decreases and glare sensitivity increases, even in the absence of ocular diseases. Because of the increasing number of elderly drivers, more drivers are affected by night vision difficulties. Vision tests, which accurately predict night driving ability, are therefore of great interest. METHODS We reviewed existing literature on age-related influences on vision and vision tests that correlate or predict night driving ability. RESULTS We identified several studies that investigated the relationship between vision tests and night driving. These studies found correlations between impaired mesopic vision or increased glare sensitivity and impaired night driving, but no correlation was found among other tests; for example, useful field of view or visual field. The correlation between photopic visual acuity, the most commonly used test when assessing elderly drivers, and night driving ability has not yet been fully clarified. CONCLUSIONS Photopic visual acuity alone is not a good predictor of night driving ability. Mesopic visual acuity and glare sensitivity seem relevant for night driving. Due to the small number of studies evaluating predictors for night driving ability, further research is needed.
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Affiliation(s)
- Nicole Gruber
- Gerontechnology and Rehabilitation Group, University of Bern, Bern, Switzerland
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230
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Remodeling of the fovea in Parkinson disease. J Neural Transm (Vienna) 2012; 120:745-53. [DOI: 10.1007/s00702-012-0909-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 10/19/2012] [Indexed: 01/24/2023]
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231
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Matynia A, Parikh S, Chen B, Kim P, McNeill DS, Nusinowitz S, Evans C, Gorin MB. Intrinsically photosensitive retinal ganglion cells are the primary but not exclusive circuit for light aversion. Exp Eye Res 2012; 105:60-9. [DOI: 10.1016/j.exer.2012.09.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 09/25/2012] [Accepted: 09/26/2012] [Indexed: 11/25/2022]
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233
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Bertrand JA, Bedetti C, Postuma RB, Monchi O, Génier Marchand D, Jubault T, Gagnon JF. Color discrimination deficits in Parkinson's disease are related to cognitive impairment and white-matter alterations. Mov Disord 2012; 27:1781-8. [PMID: 23147270 DOI: 10.1002/mds.25272] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2012] [Revised: 08/29/2012] [Accepted: 10/08/2012] [Indexed: 11/08/2022] Open
Abstract
Color discrimination deficit is a common nonmotor manifestation of Parkinson's disease (PD). However, the pathophysiology of this dysfunction remains poorly understood. Although retinal structure changes found in PD have been suggested to cause color discrimination deficits, the impact of cognitive impairment and cortical alterations remains to be determined. We investigated the contribution of cognitive impairment to color discrimination deficits in PD and correlated them with cortical anomalies. Sixty-six PD patients without dementia and 20 healthy controls performed the Farnsworth-Munsell 100 hue test and underwent a comprehensive neuropsychological assessment for mild cognitive impairment diagnosis. In a subgroup of 26 PD patients, we also used high-definition neuroanatomical magnetic resonance imaging for cortical thickness and diffusion tensor analysis. PD patients with mild cognitive impairment performed poorly on the Farnsworth-Munsell 100 hue test compared with PD patients without mild cognitive impairment and controls. In PD patients, performance on the Farnsworth-Munsell 100 hue test was correlated with measures of visuospatial abilities and executive functions. Neuroimaging analysis revealed higher mean and radial diffusivity values in right posterior white-matter structures that correlated with poor performance on the Farnsworth-Munsell 100 hue test. No cortical thickness correlation reached significance. This study showed that cognitive impairment makes a major contribution to the color discrimination deficits reported in PD. Thus, performance on the Farnsworth-Munsell 100 hue test may reflect cognitive impairment more than color discrimination deficits in PD. Poor performance on the Farnsworth-Munsell 100 hue test was also associated with white-matter alterations in right posterior brain regions.
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Affiliation(s)
- Josie-Anne Bertrand
- Center for Advanced Research in Sleep Medicine, Sacré-Coeur Hospital, Montreal, Québec, Canada
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234
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Tsironi EE, Dastiridou A, Katsanos A, Dardiotis E, Veliki S, Patramani G, Zacharaki F, Ralli S, Hadjigeorgiou GM. Perimetric and retinal nerve fiber layer findings in patients with Parkinson's disease. BMC Ophthalmol 2012; 12:54. [PMID: 23031247 PMCID: PMC3515471 DOI: 10.1186/1471-2415-12-54] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2012] [Accepted: 09/25/2012] [Indexed: 11/13/2022] Open
Abstract
Background Visual dysfunction is common in Parkinson’s disease (PD). It remains, however, unknown whether it is related to structural alterations of the retina. The aim of this study is to compare visual field (VF) findings and circumpapillary retinal nerve fiber layer (RNFL) thickness in a series of PD patients and normal controls, in order to assess possible retinal anatomical changes and/or functional damage associated with PD. Methods PD patients and controls were recruited and underwent VF testing with static automated perimetry and RNFL examination with optical coherence tomography (OCT). Cognitive performance using Mini Mental State Examination (MMSE), PD staging using modified Hoehn and Yahr (H-Y) scale and duration of the disease was recorded in PD patients. Results One randomly selected eye from each of 24 patients and 24 age-matched controls was included. OCT RNFL thickness analysis revealed no difference in the inferior, superior, nasal or temporal sectors between the groups. The average peripapillary RNFL was also similar in the two groups. However, perimetric indices of generalized sensitivity loss (mean deviation) and localized scotomas (pattern standard deviation) were worse in patients with PD compared to controls (p < 0.01). 73% of eyes of PD patients had glaucomatous-like asymmetrical hemifield defects with abnormal Glaucoma Hemifield Test and various combinations of arcuate defects (n = 12), nasal steps (n = 11) and paracentral scotomas (n = 16). Bilateral defects were found in 14 patients (58%). No correlation was found between VF indices and MMSE or H-Y scores. Conclusion PD patients may demonstrate glaucomatous-like perimetric defects even in the absence of decreased RNFL thickness.
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Affiliation(s)
- Evangelia E Tsironi
- Department of Ophthalmology, University Hospital of Larissa, Faculty of Medicine, University of Thessaly, Mezourlo 41222 Larissa, Greece.
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Postuma RB, Aarsland D, Barone P, Burn DJ, Hawkes CH, Oertel W, Ziemssen T. Identifying prodromal Parkinson's disease: pre-motor disorders in Parkinson's disease. Mov Disord 2012; 27:617-26. [PMID: 22508280 DOI: 10.1002/mds.24996] [Citation(s) in RCA: 390] [Impact Index Per Article: 32.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Increasing recognition that Parkinson's disease (PD) may start outside of the substantia nigra has led to a rapidly expanding effort to define prodromal stages of PD, before motor signs permit classical diagnosis. Many of these efforts center around the identification of clinical non-motor symptoms and signs of disease. There is now direct evidence that olfaction, rapid eye movement (REM) sleep behavior disorder (RBD), constipation, and depression can be present in prodromal PD. In addition, there is suggestive evidence that visual changes, other autonomic symptoms, and subtle cognitive changes may also be present at prodromal stages. A critical issue in utility of these prodromal markers will be assessment of sensitivity, specificity, and positive and negative predictive values. Although these have yet to be fully defined, olfactory deficits, some visual changes, and autonomic symptoms occur in the majority of PD patients at diagnosis, suggesting good potential sensitivity. However, with the exception of RBD and perhaps some specific autonomic measures, specificity, and positive predictive value of these markers may be insufficient to be used alone as identifiers of prodromal disease. The evidence for the utility of olfaction, RBD, autonomic markers, visual changes, mood disorders, and cognitive loss as markers of prodromal PD and the potential sensitivity and specificity of these markers are summarized.
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Affiliation(s)
- Ronald B Postuma
- Department of Neurology, McGill University, Montreal General Hospital, Montreal, Quebec, Canada.
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Videnovic A, Golombek D. Circadian and sleep disorders in Parkinson's disease. Exp Neurol 2012; 243:45-56. [PMID: 22935723 DOI: 10.1016/j.expneurol.2012.08.018] [Citation(s) in RCA: 152] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 08/08/2012] [Accepted: 08/14/2012] [Indexed: 01/17/2023]
Abstract
Impaired sleep and alertness, initially recognized by James Parkinson in his famous monograph "An Essay on the Shaking Palsy" in 1817, is one of the most common and disabling nonmotor symptoms of Parkinson's disease (PD). It is only recently, however, that sleep disturbances in PD have received the attention of medical and research community. Dopamine, the major neurotransmitter implicated in the pathogenesis of PD, plays a pivotal role in the regulation of sleep and circadian homeostasis. Sleep dysfunction affects up to 90% of patients with PD, and may precede the onset of the disease by decades. Sleep dysfunction in PD may be categorized into disturbances of overnight sleep and daytime alertness. Etiology of impaired sleep and alertness in PD is multifactorial. Co-existent primary sleep disorders, medication side effects, overnight re-emergence of motor symptoms, and primary neurodegeneration itself, are main causes of sleep disruption and excessive daytime sleepiness among patients with PD. Increasing body of evidence suggests that the circadian system becomes dysregulated in PD, which may lead to poor sleep and alertness. Treatment options are limited and frequently associated with unwanted side effects. Further studies that will examine pathophysiology of sleep dysfunction in PD, and focus on novel treatment approaches are therefore very much needed. In this article we review the role of dopamine in regulation of sleep and alertness and discuss main sleep and circadian disturbances associated with PD.
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Affiliation(s)
- Aleksandar Videnovic
- PD and Movement Disorders Center, Circadian Rhythms and Sleep Research Laboratory, Department of Neurology, Northwestern University, 710 N Lake Shore Dr #1106, Chicago, IL 60611, USA.
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237
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Cho KI, Searle K, Webb M, Yi H, Ferreira PA. Ranbp2 haploinsufficiency mediates distinct cellular and biochemical phenotypes in brain and retinal dopaminergic and glia cells elicited by the Parkinsonian neurotoxin, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Cell Mol Life Sci 2012; 69:3511-27. [PMID: 22821000 PMCID: PMC3445802 DOI: 10.1007/s00018-012-1071-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2012] [Revised: 06/04/2012] [Accepted: 06/21/2012] [Indexed: 11/25/2022]
Abstract
Many components and pathways transducing multifaceted and deleterious effects of stress stimuli remain ill-defined. The Ran-binding protein 2 (RanBP2) interactome modulates the expression of a range of clinical and cell-context-dependent manifestations upon a variety of stressors. We examined the role of Ranbp2 haploinsufficiency on cellular and metabolic manifestations linked to tyrosine-hydroxylase (TH+) dopaminergic neurons and glial cells of the brain and retina upon acute challenge to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a parkinsonian neurotoxin, which models facets of Parkinson disease. MPTP led to stronger akinetic parkinsonism and slower recovery in Ranbp2+/− than wild-type mice without viability changes of brain TH+-neurons of either genotype, with the exception of transient nuclear atypia via changes in chromatin condensation of Ranbp2+/− TH+-neurons. Conversely, the number of wild-type retinal TH+-amacrine neurons compared to Ranbp2+/− underwent milder declines without apoptosis followed by stronger recoveries without neurogenesis. These phenotypes were accompanied by a stronger rise of EdU+-proliferative cells and non-proliferative gliosis of GFAP+-Müller cells in wild-type than Ranbp2+/− that outlasted the MPTP-insult. Finally, MPTP-treated wild-type and Ranbp2+/− mice present distinct metabolic footprints in the brain or selective regions thereof, such as striatum, that are supportive of RanBP2-mediated regulation of interdependent metabolic pathways of lysine, cholesterol, free-fatty acids, or their β-oxidation. These studies demonstrate contrasting gene-environment phenodeviances and roles of Ranbp2 between dopaminergic and glial cells of the brain and retina upon oxidative stress-elicited signaling and factors triggering a continuum of metabolic and cellular manifestations and proxies linked to oxidative stress, and chorioretinal and neurological disorders such as Parkinson.
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Affiliation(s)
- Kyoung-in Cho
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
| | - Kelly Searle
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
- Department of Epidemiology, The Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe Street, Baltimore, 21205 MD
| | - Mason Webb
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
| | - Haiqing Yi
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
| | - Paulo A. Ferreira
- Department of Ophthalmology, Duke University Medical Center, DUEC 3802, 2351 Erwin Road, Durham, NC 27710 USA
- Department of Pathology, Duke University Medical Center, Durham, NC 27710 USA
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238
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Visual sampling during walking in people with Parkinson's disease and the influence of environment and dual-task. Brain Res 2012; 1473:35-43. [PMID: 22824332 DOI: 10.1016/j.brainres.2012.07.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2012] [Revised: 06/08/2012] [Accepted: 07/10/2012] [Indexed: 11/23/2022]
Abstract
Visuospatial dysfunction may play a crucial role in gait disturbance in Parkinson's disease (PD), in particular how visual exploration of the environment is integrated into gait control. In this study, we tested the hypothesis that people with PD would visually sample their environment less frequently than controls when walking under different levels of environmental complexity and dual-task. We also explored associations between saccadic outcomes and clinical measures. Visual sampling (saccadic frequency) and gait were measured concurrently for 21 people with PD and 12 age-matched controls during a series of walking tasks using electrooculography (EOG) synchronised with 3D motion analysis (VICON). Participants walked under four environmental conditions during single and dual-task. Saccade frequency and task duration were measured. PD participants took longer to complete all tasks than controls (p =.004). Environment and dual-task impacted on saccadic frequency especially for PD. For both groups, saccadic frequency increased when approaching a turn compared with straight walking. Prior to turning, PD made less frequent early preparatory saccades than controls (p =.012). Under dual-task conditions, people with PD made less frequent saccades than controls when walking straight ahead (p =.040) and in preparation for a turn (p =.032). Increased saccadic frequency was related to poorer attention, cognition and spatial memory in controls and people with PD for single-task conditions but not dual-task conditions. Impaired visual sampling may contribute to the gait disorder in PD, especially when navigating through complex environments and when distracted.
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239
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Botha H, Carr J. Attention and visual dysfunction in Parkinson's disease. Parkinsonism Relat Disord 2012; 18:742-7. [PMID: 22503538 DOI: 10.1016/j.parkreldis.2012.03.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2011] [Revised: 03/05/2012] [Accepted: 03/06/2012] [Indexed: 10/28/2022]
Abstract
Visual processing extends from the retinal level to the ventral temporal lobe, and is modified by top-down and bottom-up processing. Complex visual hallucinations (VH) are commonly a feature of disorders which affect temporal lobe structures, frequently in association with impairment of ascending monoaminergic pathways. When Parkinson's disease (PD) is associated with VH, pathological changes characteristically affect the temporal lobes, a finding which is recapitulated by imaging findings. However, a major association of VH is with cognitive decline, and this is typically linked to deficits in attention and working memory, both of which are modulated by dopamine. Similarly, dopamine plays a crucial role in the function of prefrontal cortex, in addition to controlling access to consciousness via gating mechanisms that are dependent on the basal ganglia.
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Affiliation(s)
- Hugo Botha
- Division of Neurology, Department of Medicine, Faculty of Health Sciences, University of Stellenbosch, PO Box 19063, Tygerberg 7505, Cape Town, South Africa
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240
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Hamilton WR, Trickler WJ, Robinson BL, Paule MG, Ali SF. Effects of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) on retinal dopaminergic system in mice. Neurosci Lett 2012; 515:107-10. [PMID: 22414866 DOI: 10.1016/j.neulet.2012.02.085] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2011] [Revised: 02/23/2012] [Accepted: 02/24/2012] [Indexed: 10/28/2022]
Abstract
The neurotoxins methamphetamine (METH) and MPTP are well-known for their effects on the nigrostriatal dopaminergic system and use in modeling neurodegenerative disorders such as Parkinson's disease. It is not well-known though, how METH or MPTP affects the visual system and specifically the retinal dopaminergic system. This study was designed to examine acute effects of multiple doses of METH and MPTP on the retinal dopaminergic system. Mice were exposed to either low- (LD) 10 mg/kg total dose or high-dose (HD) 30 mg/kg total dose, of METH or MPTP and the retinal catecholaminergic system was analyzed by HPLC. METH produced no significant changes in dopamine (DA), its metabolites 3,4-dihydroxyphenylacetic acid (DOPAC) and homovanillic acid (HVA) or DA usage in the retina. LD-MPTP produced no change in DA level, but significantly decreased DOPAC and HVA. LD-MPTP also significantly decreased DA usage as measured by the DOPAC/DA and HVA/DA ratios. HD-MPTP significantly decreased DA, DOPAC and HVA, but did not affect DA usage. Taken together these results suggest that inhibition of the DA metabolizing enzymes monoamine oxidase A (MAO) or catechol-O-methyl transferase (COMT) may take place at lower doses of MPTP treatment; conversely, higher doses of MPTP may cause decreases in DA, DOPAC and HVA through another mechanism.
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Affiliation(s)
- W Ryan Hamilton
- Neurochemistry Laboratory, Division of Neurotoxicology, National Center for Toxicological Research/USFDA, Jefferson, AR 72079, USA
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241
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Dayan E, Inzelberg R, Flash T. Altered perceptual sensitivity to kinematic invariants in Parkinson's disease. PLoS One 2012; 7:e30369. [PMID: 22363430 PMCID: PMC3281839 DOI: 10.1371/journal.pone.0030369] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 12/19/2011] [Indexed: 11/19/2022] Open
Abstract
Ample evidence exists for coupling between action and perception in neurologically healthy individuals, yet the precise nature of the internal representations shared between these domains remains unclear. One experimentally derived view is that the invariant properties and constraints characterizing movement generation are also manifested during motion perception. One prominent motor invariant is the "two-third power law," describing the strong relation between the kinematics of motion and the geometrical features of the path followed by the hand during planar drawing movements. The two-thirds power law not only characterizes various movement generation tasks but also seems to constrain visual perception of motion. The present study aimed to assess whether motor invariants, such as the two thirds power law also constrain motion perception in patients with Parkinson's disease (PD). Patients with PD and age-matched controls were asked to observe the movement of a light spot rotating on an elliptical path and to modify its velocity until it appeared to move most uniformly. As in previous reports controls tended to choose those movements close to obeying the two-thirds power law as most uniform. Patients with PD displayed a more variable behavior, choosing on average, movements closer but not equal to a constant velocity. Our results thus demonstrate impairments in how the two-thirds power law constrains motion perception in patients with PD, where this relationship between velocity and curvature appears to be preserved but scaled down. Recent hypotheses on the role of the basal ganglia in motor timing may explain these irregularities. Alternatively, these impairments in perception of movement may reflect similar deficits in motor production.
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Affiliation(s)
- Eran Dayan
- Department of Computer Science and Applied Mathematics, The Weizmann Institute of Science, Rehovot, Israel.
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242
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Gallagher DA, Schrag A. Psychosis, apathy, depression and anxiety in Parkinson's disease. Neurobiol Dis 2012; 46:581-9. [PMID: 22245219 DOI: 10.1016/j.nbd.2011.12.041] [Citation(s) in RCA: 143] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 12/19/2011] [Accepted: 12/22/2011] [Indexed: 02/06/2023] Open
Abstract
Psychiatric symptoms are important non-motor features in PD, which occur at high frequency and have significant impact on health related quality of life. This review concentrates on the prevalence, pathophysiology, diagnosis and treatment of depression, anxiety, apathy and psychosis. The pathophysiology of these disorders is complex, reflecting the widespread brainstem and cortical pathology in PD, with involvement of several neurotransmitters, including dopaminergic, serotonergic, noradrenergic and cholinergic systems. The diagnosis of psychiatric conditions, in particular affective disorders, is challenging because of the overlap of somatic features of psychiatric disorders and underlying movement disorder. The pathogenesis is likely to differ considerably from non-PD patients, and treatments used in general psychiatry services may not be as effective in PD and will require clearer clarification in well-designed clinical studies. Management strategies include adjustment of dopaminergic medication, use of psychotropic treatments and behavioural and psychological approaches. However, the future challenge will be to develop treatments developed specifically for the pathogenesis of these disorders in PD.
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243
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Taylor JP, Firbank M, Barnett N, Pearce S, Livingstone A, Mosimann U, Eyre J, McKeith IG, O'Brien JT. Visual hallucinations in dementia with Lewy bodies: transcranial magnetic stimulation study. Br J Psychiatry 2011; 199:492-500. [PMID: 22016436 PMCID: PMC3227808 DOI: 10.1192/bjp.bp.110.090373] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/09/2010] [Revised: 03/09/2011] [Accepted: 06/16/2011] [Indexed: 12/15/2022]
Abstract
BACKGROUND The aetiology of visual hallucinations is poorly understood in dementia with Lewy bodies. Pathological alterations in visual cortical excitability may be one contributory mechanism. AIMS To determine visual cortical excitability in people with dementia with Lewy bodies compared with aged-matched controls and also the relationship between visual cortical excitability and visual hallucinations in dementia with Lewy bodies. METHOD Visual cortical excitability was determined by using transcranial magnetic stimulation (TMS) applied to the occiput to elicit phosphenes (transient subjective visual responses) in 21 patients with dementia with Lewy bodies and 19 age-matched controls. RESULTS Phosphene parameters were similar between both groups. However, in the patients with dementia with Lewy bodies, TMS measures of visual cortical excitability correlated strongly with the severity of visual hallucinations (P = 0.005). Six patients with dementia with Lewy bodies experienced visual hallucination-like phosphenes (for example, seeing people or figures on stimulation) compared with none of the controls (P = 0.02). CONCLUSIONS Increased visual cortical excitability in dementia with Lewy bodies does not appear to explain visual hallucinations but it may be a marker for their severity.
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Affiliation(s)
- John-Paul Taylor
- Institute for Ageing and Health, Newcastle University, Wolfson Research Centre, Campus for Ageing and Vitality, Newcastle upon Tyne NE4 5PL, UK.
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244
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Jellinger KA. Neuropathology of sporadic Parkinson's disease: evaluation and changes of concepts. Mov Disord 2011; 27:8-30. [PMID: 22081500 DOI: 10.1002/mds.23795] [Citation(s) in RCA: 311] [Impact Index Per Article: 23.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2011] [Revised: 04/19/2011] [Accepted: 04/21/2011] [Indexed: 12/30/2022] Open
Abstract
Parkinson's disease (PD), one of the most frequent neurodegenerative disorders, is no longer considered a complex motor disorder characterized by extrapyramidal symptoms, but a progressive multisystem or-more correctly-multiorgan disease with variegated neurological and nonmotor deficiencies. It is morphologically featured not only by the degeneration of the dopaminergic nigrostriatal system, responsible for the core motor deficits, but by multifocal involvement of the central, peripheral and autonomic nervous system and other organs associated with widespread occurrence of Lewy bodies and dystrophic Lewy neurites. This results from deposition of abnormal α-synuclein (αSyn), the major protein marker of PD, and other synucleinopathies. Recent research has improved both the clinical and neuropathological diagnostic criteria of PD; it has further provided insights into the development and staging of αSyn and Lewy pathologies and has been useful in understanding the pathogenesis of PD. However, many challenges remain, for example, the role of Lewy bodies and the neurobiology of axons in the course of neurodegeneration, the relation between αSyn, Lewy pathology, and clinical deficits, as well as the interaction between αSyn and other pathologic proteins. Although genetic and experimental models have contributed to exploring the causes, pathomechanisms, and treatment options of PD, there is still a lack of an optimal animal model, and the etiology of this devastating disease is far from being elucidated.
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245
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Diederich NJ, Parent A. Parkinson's disease: acquired frailty of archaic neural networks? J Neurol Sci 2011; 314:143-51. [PMID: 22050951 DOI: 10.1016/j.jns.2011.10.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2011] [Revised: 10/02/2011] [Accepted: 10/04/2011] [Indexed: 12/21/2022]
Abstract
In Parkinson's disease (PD) many motor and non-motor symptoms are difficult to explain in terms of a purely ascending degeneration process as described by Braak. This essay proposes phylogenetic considerations for consolidating the multidimensional elements of PD. Subtle clinical analysis paired with ethological comparisons as well as patho-anatomical data suggests that disrupted automatic gait control, olfactory deficits, selected visual deficits, impaired emotional face recognition, and REM sleep behavior disorder could be due to dysfunction of phylogenetically ancient networks. Neuroanatomical and behavioral findings lead to a reconsideration of the basal ganglia, to be viewed as the nuclear core of a widely distributed neural network that arborizes throughout the primordial core of the neuraxis, including the brainstem. Fragility of the resulting multiple, closed, ancillary loops that link brainstem and forebrain components of the basal ganglia may be a nodal point, pivotal to the pathogenesis of PD. Other primitive neural networks, such as those located at cardiac or gastro-intestinal levels, may share the same vulnerability. Such a network-based hypothesis overrides the need of a fixed temporal ordering of symptoms based on putative caudal-cephalic propagation patterns of pathological lesions. It also creates testable, secondary hypotheses such as differential gene expression in different neural networks, potential early epigenetic influences, concepts of "overuse" or maladaptation of primitive networks to the constraints of adult life, and system frailty due to irreparable mitochondrial "exhaustion" in highly energy consuming postmitotic cells.
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Affiliation(s)
- Nico J Diederich
- Department of Neurosciences, Centre Hospitalier de Luxembourg, Luxembourg-City, Luxembourg.
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246
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Tzekov R, Stein L, Kaushal S. Protein misfolding and retinal degeneration. Cold Spring Harb Perspect Biol 2011; 3:a007492. [PMID: 21825021 DOI: 10.1101/cshperspect.a007492] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The retina is a highly complex and specialized organ that performs preliminary analysis of visual information. Composed of highly metabolically active tissue, the retina requires a precise and well-balanced means of maintaining its functional activity during extended periods of time. Maintenance and regulation of a vast array of different structural and functional proteins is required for normal function of the retina. This process is referred to as protein homeostasis and involves a variety of activities, including protein synthesis, folding, transport, degradation, elimination, and recycling. Deregulation of any of these activities can lead to malfunctioning of the retina, from subtle subclinical signs to severe retinal degenerative diseases leading to blindness. Examples of retinal degenerative diseases caused by disruption of protein homeostasis include retinitis pigmentosa and Stargardt's disease. A detailed discussion of the role of disruption in protein homeostasis in these and other retinal diseases is presented, followed by examples of some existing and potential treatments.
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Affiliation(s)
- Radouil Tzekov
- Department of Ophthalmology, University of Massachusetts Medical School, Worcester, Massachusetts 01655, USA
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247
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Esteve-Rudd J, Fernández-Sánchez L, Lax P, De Juan E, Martín-Nieto J, Cuenca N. Rotenone induces degeneration of photoreceptors and impairs the dopaminergic system in the rat retina. Neurobiol Dis 2011; 44:102-15. [DOI: 10.1016/j.nbd.2011.06.009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2011] [Revised: 05/24/2011] [Accepted: 06/16/2011] [Indexed: 12/21/2022] Open
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248
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Biomarkers of Parkinson's disease and Dementia with Lewy bodies. Prog Neurobiol 2011; 95:601-13. [PMID: 21983334 DOI: 10.1016/j.pneurobio.2011.09.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2011] [Revised: 09/04/2011] [Accepted: 09/06/2011] [Indexed: 01/22/2023]
Abstract
Parkinson's disease (PD) and Dementia with Lewy bodies (DLB) are progressive and disabling neurodegenerative disorders, in which signs and symptoms overlap with each other and with other neurodegenerative conditions. Currently, diagnosis, measurement of progression, and response to therapeutic intervention rely upon clinical observation. However, there remains a critical need for validated biomarkers in each of these areas. A definitive diagnostic test would improve clinical management and enrollment into clinical trials. An objective measure of progression is vitally important in identifying neuroprotective interventions. Biomarkers may also provide insight into pathogenesis, and might therefore suggest possible novel targets for therapeutic intervention. In addition, certain biomarkers might be of use in monitoring the biochemical and physiological effects of therapeutic interventions. Development of diagnostic biomarkers has focused until recently upon imaging techniques based upon measuring loss of dopamine neurons. Additionally, advances in understanding the genetic contribution to neurodegenerative disorders, in particular in PD, have identified multiple causative genes and risk factors that in some cases may help estimate PD risk. However, recent availability of increasingly sophisticated bioinformatics technology has rendered development of fluid biomarkers feasible, opening the possibility of generally accessible blood or cerebrospinal fluid (CSF) tests that could impact upon diagnosis, management, and research in PD, PDD, and DLB.
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249
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Abstract
BACKGROUND Motor deficits associated with Parkinson's disease (PD) have been well described, yet little attention has been paid to non-motor symptoms, especially cortical visual dysfunction. We investigated stereopsis, as well as the relationship between stereopsis and other cognitive function, in a sample of PD patients. METHODS We used Titmus stereotest plates for assessing stereopsis. Fifty-nine subjects (29 PD patients and 30 normal controls) were included in this study. The included patients underwent a neurological examination, clinical rating scale and neuropsychological tests. RESULTS Drug naïve PD patients showed decreased stereopsis on the Titmus fly stereopsis test (Pearson χ2=23.80, p<0.001) compared to PD patients with normal stereopsis. The Hoehn-Yahr stages and Unified Parkinson's Disease Rating Scale motor scores were significantly higher in patients with PD with abnormal stereopsis than in patients with PD with normal stereopsis (p=0.026; p=0.046). The frequency of abnormal visual perception/constructive function was greater in patients with PD with abnormal stereopsis compared to patients with PD with normal stereopsis (Pearson χ2=5.11, p=0.024). CONCLUSION These findings suggest that stereopsis deficits and visual perception/constructive dysfunction are common in de novo PD patients.
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250
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Jellinger KA. Synuclein deposition and non-motor symptoms in Parkinson disease. J Neurol Sci 2011; 310:107-11. [PMID: 21570091 DOI: 10.1016/j.jns.2011.04.012] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 04/18/2011] [Accepted: 04/19/2011] [Indexed: 11/24/2022]
Abstract
Parkinson disease (PD) is a multisystem neurodegenerative disorder clinically characterized by motor and non-motor (NM) symptoms. The causes of NM symptoms in PD, many of which antedating motor dysfunction, are multifocal and unlikely explained by single lesions. They include olfactory, autonomic, sensory, skin, sleep, visual, neuropsychiatric, and other manifestations. Most NM features in PD are related to α-synuclein pathology which, in addition to the dopaminergic striatonigral system, involves non-nigral brainstem nuclei, sympathetic, parasympathetic, enteric and pelvic plexuses, cardiac systems, submandibular gland, adrenal medulla, skin, retina, and other visceral organs. This suggests a topographical and chronological spread of lesions, particularly in the prodromal stages of the disease, which, however, awaits further confirmation. A few animal models are available that recapitulate NM symptoms in human PD, but their validity is under discussion. More studies are warranted to refine the exact correlations between presymptomatic and late-developing NM features of PD and α-synuclein pathology as a basis for more effective preventive and therapeutic options of this devastating disease.
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Affiliation(s)
- Kurt A Jellinger
- Institute of Clinical Neurobiology, Kenyongasse 18, A-1070 Vienna, Austria.
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