UpToDate
Official reprint from UpToDate®
www.uptodate.com ©2016 UpToDate®

Cognitive impairment and dementia in Parkinson disease

Author
Robert L Rodnitzky, MD
Section Editor
Steven T DeKosky, MD, FAAN, FACP, FANA
Deputy Editor
April F Eichler, MD, MPH

INTRODUCTION

Cognitive dysfunction is common in Parkinson disease (PD) and exists on a continuum of severity; prevalence increases with the duration of the movement disorder. When severe, dementia often surpasses the motor features of PD as a major cause of disability and mortality.

While PD can coexist with other common causes of dementia, such as Alzheimer disease and vascular dementia, mild cognitive impairment and dementia are increasingly recognized as a common feature of PD itself. The clinical characteristics and course of cognitive impairment, its pathological features, and the most appropriate treatment are areas of current investigation. Clinical features can generally distinguish between PD and other movement disorders associated with dementia, such as dementia with Lewy bodies or progressive supranuclear palsy. However, whether PD dementia (PDD) and dementia with Lewy bodies are distinct disorders, or whether they represent different presentations of the same disease, is an area of debate and investigation [1].

This topic will discuss cognitive impairment and dementia associated with Parkinson disease. Other aspects of Parkinson disease and dementia with Lewy bodies are discussed separately. (See "Clinical manifestations of Parkinson disease" and "Management of nonmotor symptoms in Parkinson disease" and "Pharmacologic treatment of Parkinson disease" and "Epidemiology, pathology, and pathogenesis of dementia with Lewy bodies" and "Clinical features and diagnosis of dementia with Lewy bodies" and "Prognosis and treatment of dementia with Lewy bodies".)

EPIDEMIOLOGY

Incidence and prevalence — Dementia is a common feature of Parkinson disease (PD) [2]. A meta-analysis of 27 cross-sectional studies largely drawn from academic centers found a mean prevalence of 40 percent; however, this study did not distinguish Parkinson disease dementia (PDD) from dementia with Lewy bodies (DLB) [3]. In a review of 24 studies with more exacting criteria, 31 percent of 1767 PD patients were found to have dementia [4]. In the same study, PD dementia was found to account for 3.6 percent of all cases of dementia in the population.

In prospective cohort studies, the incidence rate of dementia in patients with PD is consistently estimated at approximately 100 per 100,00 patient years, a rate almost five- to sixfold higher than controls without PD [5,6]. A cumulative incidence of dementia as high as 80 percent has been reported in patients with PD [7] and, conditional on survival, 80 to 90 percent by age 90 years [8].

                               

Subscribers log in here

To continue reading this article, you must log in with your personal, hospital, or group practice subscription. For more information or to purchase a personal subscription, click below on the option that best describes you:
Literature review current through: Nov 2016. | This topic last updated: Tue Nov 03 00:00:00 GMT+00:00 2015.
The content on the UpToDate website is not intended nor recommended as a substitute for medical advice, diagnosis, or treatment. Always seek the advice of your own physician or other qualified health care professional regarding any medical questions or conditions. The use of this website is governed by the UpToDate Terms of Use ©2016 UpToDate, Inc.
References
Top
  1. Lippa CF, Duda JE, Grossman M, et al. DLB and PDD boundary issues: diagnosis, treatment, molecular pathology, and biomarkers. Neurology 2007; 68:812.
  2. Svenningsson P, Westman E, Ballard C, Aarsland D. Cognitive impairment in patients with Parkinson's disease: diagnosis, biomarkers, and treatment. Lancet Neurol 2012; 11:697.
  3. Cummings JL. Intellectual impairment in Parkinson's disease: clinical, pathologic, and biochemical correlates. J Geriatr Psychiatry Neurol 1988; 1:24.
  4. Aarsland D, Zaccai J, Brayne C. A systematic review of prevalence studies of dementia in Parkinson's disease. Mov Disord 2005; 20:1255.
  5. Hobson P, Meara J. Risk and incidence of dementia in a cohort of older subjects with Parkinson's disease in the United Kingdom. Mov Disord 2004; 19:1043.
  6. Aarsland D, Andersen K, Larsen JP, et al. Risk of dementia in Parkinson's disease: a community-based, prospective study. Neurology 2001; 56:730.
  7. Aarsland D, Andersen K, Larsen JP, et al. Prevalence and characteristics of dementia in Parkinson disease: an 8-year prospective study. Arch Neurol 2003; 60:387.
  8. Buter TC, van den Hout A, Matthews FE, et al. Dementia and survival in Parkinson disease: a 12-year population study. Neurology 2008; 70:1017.
  9. Louis ED, Schupf N, Manly J, et al. Association between mild parkinsonian signs and mild cognitive impairment in a community. Neurology 2005; 64:1157.
  10. Muslimovic D, Post B, Speelman JD, Schmand B. Cognitive profile of patients with newly diagnosed Parkinson disease. Neurology 2005; 65:1239.
  11. Foltynie T, Brayne CE, Robbins TW, Barker RA. The cognitive ability of an incident cohort of Parkinson's patients in the UK. The CamPaIGN study. Brain 2004; 127:550.
  12. Poletti M, Frosini D, Pagni C, et al. Mild cognitive impairment and cognitive-motor relationships in newly diagnosed drug-naive patients with Parkinson's disease. J Neurol Neurosurg Psychiatry 2012; 83:601.
  13. Weintraub D, Simuni T, Caspell-Garcia C, et al. Cognitive performance and neuropsychiatric symptoms in early, untreated Parkinson's disease. Mov Disord 2015; 30:919.
  14. Mayeux R, Denaro J, Hemenegildo N, et al. A population-based investigation of Parkinson's disease with and without dementia. Relationship to age and gender. Arch Neurol 1992; 49:492.
  15. Stern Y, Marder K, Tang MX, Mayeux R. Antecedent clinical features associated with dementia in Parkinson's disease. Neurology 1993; 43:1690.
  16. Hughes TA, Ross HF, Musa S, et al. A 10-year study of the incidence of and factors predicting dementia in Parkinson's disease. Neurology 2000; 54:1596.
  17. Reid WG, Hely MA, Morris JG, et al. A longitudinal of Parkinson's disease: clinical and neuropsychological correlates of dementia. J Clin Neurosci 1996; 3:327.
  18. Levy G, Schupf N, Tang MX, et al. Combined effect of age and severity on the risk of dementia in Parkinson's disease. Ann Neurol 2002; 51:722.
  19. Anang JB, Gagnon JF, Bertrand JA, et al. Predictors of dementia in Parkinson disease: a prospective cohort study. Neurology 2014; 83:1253.
  20. Alcalay RN, Caccappolo E, Mejia-Santana H, et al. Cognitive performance of GBA mutation carriers with early-onset PD: the CORE-PD study. Neurology 2012; 78:1434.
  21. Chahine LM, Qiang J, Ashbridge E, et al. Clinical and biochemical differences in patients having Parkinson disease with vs without GBA mutations. JAMA Neurol 2013; 70:852.
  22. Inzelberg R, Hassin-Baer S, Jankovic J. Genetic movement disorders in patients of Jewish ancestry. JAMA Neurol 2014; 71:1567.
  23. Obi T, Nishioka K, Ross OA, et al. Clinicopathologic study of a SNCA gene duplication patient with Parkinson disease and dementia. Neurology 2008; 70:238.
  24. Bostantjopoulou S, Katsarou Z, Papadimitriou A, et al. Clinical features of parkinsonian patients with the alpha-synuclein (G209A) mutation. Mov Disord 2001; 16:1007.
  25. Fuchs J, Nilsson C, Kachergus J, et al. Phenotypic variation in a large Swedish pedigree due to SNCA duplication and triplication. Neurology 2007; 68:916.
  26. Grünewald A, Kasten M, Ziegler A, Klein C. Next-generation phenotyping using the parkin example: time to catch up with genetics. JAMA Neurol 2013; 70:1186.
  27. de Lau LM, Schipper CM, Hofman A, et al. Prognosis of Parkinson disease: risk of dementia and mortality: the Rotterdam Study. Arch Neurol 2005; 62:1265.
  28. Pankratz N, Byder L, Halter C, et al. Presence of an APOE4 allele results in significantly earlier onset of Parkinson's disease and a higher risk with dementia. Mov Disord 2006; 21:45.
  29. Harhangi BS, de Rijk MC, van Duijn CM, et al. APOE and the risk of PD with or without dementia in a population-based study. Neurology 2000; 54:1272.
  30. Huang X, Chen P, Kaufer DI, et al. Apolipoprotein E and dementia in Parkinson disease: a meta-analysis. Arch Neurol 2006; 63:189.
  31. Morley JF, Xie SX, Hurtig HI, et al. Genetic influences on cognitive decline in Parkinson's disease. Mov Disord 2012; 27:512.
  32. Jasinska-Myga B, Opala G, Goetz CG, et al. Apolipoprotein E gene polymorphism, total plasma cholesterol level, and Parkinson disease dementia. Arch Neurol 2007; 64:261.
  33. Williams-Gray CH, Goris A, Saiki M, et al. Apolipoprotein E genotype as a risk factor for susceptibility to and dementia in Parkinson's disease. J Neurol 2009; 256:493.
  34. Williams-Gray CH, Evans JR, Goris A, et al. The distinct cognitive syndromes of Parkinson's disease: 5 year follow-up of the CamPaIGN cohort. Brain 2009; 132:2958.
  35. Goris A, Williams-Gray CH, Clark GR, et al. Tau and alpha-synuclein in susceptibility to, and dementia in, Parkinson's disease. Ann Neurol 2007; 62:145.
  36. Aarsland D, Perry R, Brown A, et al. Neuropathology of dementia in Parkinson's disease: a prospective, community-based study. Ann Neurol 2005; 58:773.
  37. Apaydin H, Ahlskog JE, Parisi JE, et al. Parkinson disease neuropathology: later-developing dementia and loss of the levodopa response. Arch Neurol 2002; 59:102.
  38. Kövari E, Gold G, Herrmann FR, et al. Lewy body densities in the entorhinal and anterior cingulate cortex predict cognitive deficits in Parkinson's disease. Acta Neuropathol 2003; 106:83.
  39. Edison P, Rowe CC, Rinne JO, et al. Amyloid load in Parkinson's disease dementia and Lewy body dementia measured with [11C]PIB positron emission tomography. J Neurol Neurosurg Psychiatry 2008; 79:1331.
  40. Petrou M, Bohnen NI, Müller ML, et al. Aβ-amyloid deposition in patients with Parkinson disease at risk for development of dementia. Neurology 2012; 79:1161.
  41. Kotzbauer PT, Cairns NJ, Campbell MC, et al. Pathologic accumulation of α-synuclein and Aβ in Parkinson disease patients with dementia. Arch Neurol 2012; 69:1326.
  42. Irwin DJ, White MT, Toledo JB, et al. Neuropathologic substrates of Parkinson disease dementia. Ann Neurol 2012; 72:587.
  43. Braak H, Rüb U, Jansen Steur EN, et al. Cognitive status correlates with neuropathologic stage in Parkinson disease. Neurology 2005; 64:1404.
  44. Parkkinen L, Pirttilä T, Alafuzoff I. Applicability of current staging/categorization of alpha-synuclein pathology and their clinical relevance. Acta Neuropathol 2008; 115:399.
  45. Hall H, Reyes S, Landeck N, et al. Hippocampal Lewy pathology and cholinergic dysfunction are associated with dementia in Parkinson's disease. Brain 2014; 137:2493.
  46. Colosimo C, Hughes AJ, Kilford L, Lees AJ. Lewy body cortical involvement may not always predict dementia in Parkinson's disease. J Neurol Neurosurg Psychiatry 2003; 74:852.
  47. Siderowf A, Xie SX, Hurtig H, et al. CSF amyloid {beta} 1-42 predicts cognitive decline in Parkinson disease. Neurology 2010; 75:1055.
  48. Alves G, Brønnick K, Aarsland D, et al. CSF amyloid-beta and tau proteins, and cognitive performance, in early and untreated Parkinson's disease: the Norwegian ParkWest study. J Neurol Neurosurg Psychiatry 2010; 81:1080.
  49. Alves G, Lange J, Blennow K, et al. CSF Aβ42 predicts early-onset dementia in Parkinson disease. Neurology 2014; 82:1784.
  50. Burton EJ, McKeith IG, Burn DJ, O'Brien JT. Brain atrophy rates in Parkinson's disease with and without dementia using serial magnetic resonance imaging. Mov Disord 2005; 20:1571.
  51. Nagano-Saito A, Washimi Y, Arahata Y, et al. Cerebral atrophy and its relation to cognitive impairment in Parkinson disease. Neurology 2005; 64:224.
  52. Beyer MK, Janvin CC, Larsen JP, Aarsland D. A magnetic resonance imaging study of patients with Parkinson's disease with mild cognitive impairment and dementia using voxel-based morphometry. J Neurol Neurosurg Psychiatry 2007; 78:254.
  53. Melzer TR, Watts R, MacAskill MR, et al. Grey matter atrophy in cognitively impaired Parkinson's disease. J Neurol Neurosurg Psychiatry 2012; 83:188.
  54. Carlesimo GA, Piras F, Assogna F, et al. Hippocampal abnormalities and memory deficits in Parkinson disease: a multimodal imaging study. Neurology 2012; 78:1939.
  55. Shin J, Choi S, Lee JE, et al. Subcortical white matter hyperintensities within the cholinergic pathways of Parkinson's disease patients according to cognitive status. J Neurol Neurosurg Psychiatry 2012; 83:315.
  56. Rahkonen T, Eloniemi-Sulkava U, Rissanen S, et al. Dementia with Lewy bodies according to the consensus criteria in a general population aged 75 years or older. J Neurol Neurosurg Psychiatry 2003; 74:720.
  57. McKeith IG, Galasko D, Kosaka K, et al. Consensus guidelines for the clinical and pathologic diagnosis of dementia with Lewy bodies (DLB): report of the consortium on DLB international workshop. Neurology 1996; 47:1113.
  58. Stevens T, Livingston G, Kitchen G, et al. Islington study of dementia subtypes in the community. Br J Psychiatry 2002; 180:270.
  59. Mori H. Pathological substrate of dementia in Parkinson's disease--its relation to DLB and DLBD. Parkinsonism Relat Disord 2005; 11 Suppl 1:S41.
  60. Tsuboi Y, Dickson DW. Dementia with Lewy bodies and Parkinson's disease with dementia: are they different? Parkinsonism Relat Disord 2005; 11 Suppl 1:S47.
  61. Ballard C, Ziabreva I, Perry R, et al. Differences in neuropathologic characteristics across the Lewy body dementia spectrum. Neurology 2006; 67:1931.
  62. Perry EK, Curtis M, Dick DJ, et al. Cholinergic correlates of cognitive impairment in Parkinson's disease: comparisons with Alzheimer's disease. J Neurol Neurosurg Psychiatry 1985; 48:413.
  63. Mattila PM, Röyttä M, Lönnberg P, et al. Choline acetytransferase activity and striatal dopamine receptors in Parkinson's disease in relation to cognitive impairment. Acta Neuropathol 2001; 102:160.
  64. Bohnen NI, Kaufer DI, Ivanco LS, et al. Cortical cholinergic function is more severely affected in parkinsonian dementia than in Alzheimer disease: an in vivo positron emission tomographic study. Arch Neurol 2003; 60:1745.
  65. Bohnen NI, Kaufer DI, Hendrickson R, et al. Cognitive correlates of cortical cholinergic denervation in Parkinson's disease and parkinsonian dementia. J Neurol 2006; 253:242.
  66. Shimada H, Hirano S, Shinotoh H, et al. Mapping of brain acetylcholinesterase alterations in Lewy body disease by PET. Neurology 2009; 73:273.
  67. Ehrt U, Broich K, Larsen JP, et al. Use of drugs with anticholinergic effect and impact on cognition in Parkinson's disease: a cohort study. J Neurol Neurosurg Psychiatry 2010; 81:160.
  68. Press DZ, Mechanic DJ, Tarsy D, Manoach DS. Cognitive slowing in Parkinson's disease resolves after practice. J Neurol Neurosurg Psychiatry 2002; 73:524.
  69. Ekman U, Eriksson J, Forsgren L, et al. Functional brain activity and presynaptic dopamine uptake in patients with Parkinson's disease and mild cognitive impairment: a cross-sectional study. Lancet Neurol 2012; 11:679.
  70. Marini P, Ramat S, Ginestroni A, Paganini M. Deficit of short-term memory in newly diagnosed untreated parkinsonian patients: reversal after L-dopa therapy. Neurol Sci 2003; 24:184.
  71. Morrison CE, Borod JC, Brin MF, et al. Effects of levodopa on cognitive functioning in moderate-to-severe Parkinson's disease (MSPD). J Neural Transm (Vienna) 2004; 111:1333.
  72. Ballanger B, Strafella AP, van Eimeren T, et al. Serotonin 2A receptors and visual hallucinations in Parkinson disease. Arch Neurol 2010; 67:416.
  73. Huot P, Johnston TH, Darr T, et al. Increased 5-HT2A receptors in the temporal cortex of parkinsonian patients with visual hallucinations. Mov Disord 2010; 25:1399.
  74. Levin BE, Llabre MM, Reisman S, et al. Visuospatial impairment in Parkinson's disease. Neurology 1991; 41:365.
  75. Stern Y, Richards M, Sano M, Mayeux R. Comparison of cognitive changes in patients with Alzheimer's and Parkinson's disease. Arch Neurol 1993; 50:1040.
  76. Aarsland D, Brønnick K, Larsen JP, et al. Cognitive impairment in incident, untreated Parkinson disease: the Norwegian ParkWest study. Neurology 2009; 72:1121.
  77. Emre M, Aarsland D, Brown R, et al. Clinical diagnostic criteria for dementia associated with Parkinson's disease. Mov Disord 2007; 22:1689.
  78. Raskin SA, Borod JC, Tweedy J. Neuropsychological aspects of Parkinson's disease. Neuropsychol Rev 1990; 1:185.
  79. Uc EY, Rizzo M, Anderson SW, et al. Visual dysfunction in Parkinson disease without dementia. Neurology 2005; 65:1907.
  80. Bronnick K, Ehrt U, Emre M, et al. Attentional deficits affect activities of daily living in dementia-associated with Parkinson's disease. J Neurol Neurosurg Psychiatry 2006; 77:1136.
  81. Aarsland D, Bronnick K, Williams-Gray C, et al. Mild cognitive impairment in Parkinson disease: a multicenter pooled analysis. Neurology 2010; 75:1062.
  82. Emre M. Dementia in Parkinson's disease: cause and treatment. Curr Opin Neurol 2004; 17:399.
  83. Taylor JP, Rowan EN, Lett D, et al. Poor attentional function predicts cognitive decline in patients with non-demented Parkinson's disease independent of motor phenotype. J Neurol Neurosurg Psychiatry 2008; 79:1318.
  84. Litvan I, Goldman JG, Tröster AI, et al. Diagnostic criteria for mild cognitive impairment in Parkinson's disease: Movement Disorder Society Task Force guidelines. Mov Disord 2012; 27:349.
  85. Hu MT, Szewczyk-Królikowski K, Tomlinson P, et al. Predictors of cognitive impairment in an early stage Parkinson's disease cohort. Mov Disord 2014; 29:351.
  86. Noe E, Marder K, Bell KL, et al. Comparison of dementia with Lewy bodies to Alzheimer's disease and Parkinson's disease with dementia. Mov Disord 2004; 19:60.
  87. Ballard CG, Aarsland D, McKeith I, et al. Fluctuations in attention: PD dementia vs DLB with parkinsonism. Neurology 2002; 59:1714.
  88. Bronnick K, Emre M, Lane R, et al. Profile of cognitive impairment in dementia associated with Parkinson's disease compared with Alzheimer's disease. J Neurol Neurosurg Psychiatry 2007; 78:1064.
  89. Williams DR, Lees AJ. Visual hallucinations in the diagnosis of idiopathic Parkinson's disease: a retrospective autopsy study. Lancet Neurol 2005; 4:605.
  90. Aarsland D, Brønnick K, Ehrt U, et al. Neuropsychiatric symptoms in patients with Parkinson's disease and dementia: frequency, profile and associated care giver stress. J Neurol Neurosurg Psychiatry 2007; 78:36.
  91. Aarsland D, Taylor JP, Weintraub D. Psychiatric issues in cognitive impairment. Mov Disord 2014; 29:651.
  92. Fénelon G, Mahieux F, Huon R, Ziégler M. Hallucinations in Parkinson's disease: prevalence, phenomenology and risk factors. Brain 2000; 123 ( Pt 4):733.
  93. Galvin JE, Pollack J, Morris JC. Clinical phenotype of Parkinson disease dementia. Neurology 2006; 67:1605.
  94. Kandiah N, Narasimhalu K, Lau PN, et al. Cognitive decline in early Parkinson's disease. Mov Disord 2009; 24:605.
  95. Boeve BF, Silber MH, Ferman TJ, et al. Clinicopathologic correlations in 172 cases of rapid eye movement sleep behavior disorder with or without a coexisting neurologic disorder. Sleep Med 2013; 14:754.
  96. Vendette M, Gagnon JF, Décary A, et al. REM sleep behavior disorder predicts cognitive impairment in Parkinson disease without dementia. Neurology 2007; 69:1843.
  97. Gagnon JF, Vendette M, Postuma RB, et al. Mild cognitive impairment in rapid eye movement sleep behavior disorder and Parkinson's disease. Ann Neurol 2009; 66:39.
  98. Burn DJ, Rowan EN, Allan LM, et al. Motor subtype and cognitive decline in Parkinson's disease, Parkinson's disease with dementia, and dementia with Lewy bodies. J Neurol Neurosurg Psychiatry 2006; 77:585.
  99. Burn DJ, Rowan EN, Minett T, et al. Extrapyramidal features in Parkinson's disease with and without dementia and dementia with Lewy bodies: A cross-sectional comparative study. Mov Disord 2003; 18:884.
  100. Verbaan D, Marinus J, Visser M, et al. Cognitive impairment in Parkinson's disease. J Neurol Neurosurg Psychiatry 2007; 78:1182.
  101. Janvin CC, Larsen JP, Aarsland D, Hugdahl K. Subtypes of mild cognitive impairment in Parkinson's disease: progression to dementia. Mov Disord 2006; 21:1343.
  102. Pigott K, Rick J, Xie SX, et al. Longitudinal study of normal cognition in Parkinson disease. Neurology 2015; 85:1276.
  103. McKeith I, Mintzer J, Aarsland D, et al. Dementia with Lewy bodies. Lancet Neurol 2004; 3:19.
  104. McKeith IG, Dickson DW, Lowe J, et al. Diagnosis and management of dementia with Lewy bodies: third report of the DLB Consortium. Neurology 2005; 65:1863.
  105. Molloy S, McKeith IG, O'Brien JT, Burn DJ. The role of levodopa in the management of dementia with Lewy bodies. J Neurol Neurosurg Psychiatry 2005; 76:1200.
  106. Mega MS, Masterman DL, Benson DF, et al. Dementia with Lewy bodies: reliability and validity of clinical and pathologic criteria. Neurology 1996; 47:1403.
  107. Galasko D, Katzman R, Salmon DP, Hansen L. Clinical and neuropathological findings in Lewy body dementias. Brain Cogn 1996; 31:166.
  108. Beyer MK, Larsen JP, Aarsland D. Gray matter atrophy in Parkinson disease with dementia and dementia with Lewy bodies. Neurology 2007; 69:747.
  109. Lee JE, Park HJ, Park B, et al. A comparative analysis of cognitive profiles and white-matter alterations using voxel-based diffusion tensor imaging between patients with Parkinson's disease dementia and dementia with Lewy bodies. J Neurol Neurosurg Psychiatry 2010; 81:320.
  110. Seppi K, Rascol O. Dementia with Lewy bodies and Parkinson disease with dementia: can MRI make the difference? Neurology 2007; 69:717.
  111. Litvan I, Campbell G, Mangone CA, et al. Which clinical features differentiate progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome) from related disorders? A clinicopathological study. Brain 1997; 120 ( Pt 1):65.
  112. Litvan I, Agid Y, Jankovic J, et al. Accuracy of clinical criteria for the diagnosis of progressive supranuclear palsy (Steele-Richardson-Olszewski syndrome). Neurology 1996; 46:922.
  113. Quinn N. Parkinsonism--recognition and differential diagnosis. BMJ 1995; 310:447.
  114. Litvan I, Mega MS, Cummings JL, Fairbanks L. Neuropsychiatric aspects of progressive supranuclear palsy. Neurology 1996; 47:1184.
  115. Christine CW, Aminoff MJ. Clinical differentiation of parkinsonian syndromes: prognostic and therapeutic relevance. Am J Med 2004; 117:412.
  116. Bak TH, Crawford LM, Hearn VC, et al. Subcortical dementia revisited: similarities and differences in cognitive function between progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and multiple system atrophy (MSA). Neurocase 2005; 11:268.
  117. Brown RG, Lacomblez L, Landwehrmeyer BG, et al. Cognitive impairment in patients with multiple system atrophy and progressive supranuclear palsy. Brain 2010; 133:2382.
  118. Armstrong MJ, Litvan I, Lang AE, et al. Criteria for the diagnosis of corticobasal degeneration. Neurology 2013; 80:496.
  119. Portet F, Scarmeas N, Cosentino S, et al. Extrapyramidal signs before and after diagnosis of incident Alzheimer disease in a prospective population study. Arch Neurol 2009; 66:1120.
  120. Dalrymple-Alford JC, MacAskill MR, Nakas CT, et al. The MoCA: well-suited screen for cognitive impairment in Parkinson disease. Neurology 2010; 75:1717.
  121. Goldman JG, Holden S, Ouyang B, et al. Diagnosing PD-MCI by MDS Task Force criteria: how many and which neuropsychological tests? Mov Disord 2015; 30:402.
  122. Miyasaki JM, Shannon K, Voon V, et al. Practice Parameter: evaluation and treatment of depression, psychosis, and dementia in Parkinson disease (an evidence-based review): report of the Quality Standards Subcommittee of the American Academy of Neurology. Neurology 2006; 66:996.
  123. Leentjens AF, Verhey FR, Luijckx GJ, Troost J. The validity of the Beck Depression Inventory as a screening and diagnostic instrument for depression in patients with Parkinson's disease. Mov Disord 2000; 15:1221.
  124. Leentjens AF, Verhey FR, Lousberg R, et al. The validity of the Hamilton and Montgomery-Asberg depression rating scales as screening and diagnostic tools for depression in Parkinson's disease. Int J Geriatr Psychiatry 2000; 15:644.
  125. Naarding P, Leentjens AF, van Kooten F, Verhey FR. Disease-specific properties of the Rating Scale for Depression in patients with stroke, Alzheimer's dementia, and Parkinson's disease. J Neuropsychiatry Clin Neurosci 2002; 14:329.
  126. Goldman JG, Holden S, Bernard B, et al. Defining optimal cutoff scores for cognitive impairment using Movement Disorder Society Task Force criteria for mild cognitive impairment in Parkinson's disease. Mov Disord 2013; 28:1972.
  127. Rolinski M, Fox C, Maidment I, McShane R. Cholinesterase inhibitors for dementia with Lewy bodies, Parkinson's disease dementia and cognitive impairment in Parkinson's disease. Cochrane Database Syst Rev 2012; :CD006504.
  128. Emre M, Aarsland D, Albanese A, et al. Rivastigmine for dementia associated with Parkinson's disease. N Engl J Med 2004; 351:2509.
  129. Maidment I, Fox C, Boustani M. Cholinesterase inhibitors for Parkinson's disease dementia. Cochrane Database Syst Rev 2006; :CD004747.
  130. Ravina B, Putt M, Siderowf A, et al. Donepezil for dementia in Parkinson's disease: a randomised, double blind, placebo controlled, crossover study. J Neurol Neurosurg Psychiatry 2005; 76:934.
  131. Aarsland D, Laake K, Larsen JP, Janvin C. Donepezil for cognitive impairment in Parkinson's disease: a randomised controlled study. J Neurol Neurosurg Psychiatry 2002; 72:708.
  132. Linazasoro G, Lasa A, Van Blercom N. Efficacy and safety of donepezil in the treatment of executive dysfunction in Parkinson disease: a pilot study. Clin Neuropharmacol 2005; 28:176.
  133. Aarsland D, Hutchinson M, Larsen JP. Cognitive, psychiatric and motor response to galantamine in Parkinson's disease with dementia. Int J Geriatr Psychiatry 2003; 18:937.
  134. Grace J, Amick MM, Friedman JH. A double-blind comparison of galantamine hydrobromide ER and placebo in Parkinson disease. J Neurol Neurosurg Psychiatry 2009; 80:18.
  135. Dubois B, Tolosa E, Katzenschlager R, et al. Donepezil in Parkinson's disease dementia: a randomized, double-blind efficacy and safety study. Mov Disord 2012; 27:1230.
  136. Wang HF, Yu JT, Tang SW, et al. Efficacy and safety of cholinesterase inhibitors and memantine in cognitive impairment in Parkinson's disease, Parkinson's disease dementia, and dementia with Lewy bodies: systematic review with meta-analysis and trial sequential analysis. J Neurol Neurosurg Psychiatry 2015; 86:135.
  137. Pagano G, Rengo G, Pasqualetti G, et al. Cholinesterase inhibitors for Parkinson's disease: a systematic review and meta-analysis. J Neurol Neurosurg Psychiatry 2015; 86:767.
  138. Minett TS, Thomas A, Wilkinson LM, et al. What happens when donepezil is suddenly withdrawn? An open label trial in dementia with Lewy bodies and Parkinson's disease with dementia. Int J Geriatr Psychiatry 2003; 18:988.
  139. Aarsland D, Ballard C, Walker Z, et al. Memantine in patients with Parkinson's disease dementia or dementia with Lewy bodies: a double-blind, placebo-controlled, multicentre trial. Lancet Neurol 2009; 8:613.
  140. Emre M, Tsolaki M, Bonuccelli U, et al. Memantine for patients with Parkinson's disease dementia or dementia with Lewy bodies: a randomised, double-blind, placebo-controlled trial. Lancet Neurol 2010; 9:969.
  141. Leroi I, Overshott R, Byrne EJ, et al. Randomized controlled trial of memantine in dementia associated with Parkinson's disease. Mov Disord 2009; 24:1217.
  142. Ridha BH, Josephs KA, Rossor MN. Delusions and hallucinations in dementia with Lewy bodies: worsening with memantine. Neurology 2005; 65:481.
  143. Menendez-Gonzalez M, Calatayud MT, Blazquez-Menes B. Exacerbation of Lewy bodies dementia due to memantine. J Alzheimers Dis 2005; 8:289.
  144. Monastero R, Camarda C, Pipia C, Camarda R. Visual hallucinations and agitation in Alzheimer's disease due to memantine: report of three cases. J Neurol Neurosurg Psychiatry 2007; 78:546.
  145. Fernandez HH, Trieschmann ME, Burke MA, Friedman JH. Quetiapine for psychosis in Parkinson's disease versus dementia with Lewy bodies. J Clin Psychiatry 2002; 63:513.
  146. Morgante L, Epifanio A, Spina E, et al. Quetiapine versus clozapine: a preliminary report of comparative effects on dopaminergic psychosis in patients with Parkinson's disease. Neurol Sci 2002; 23 Suppl 2:S89.
  147. Molloy SA, Rowan EN, O'Brien JT, et al. Effect of levodopa on cognitive function in Parkinson's disease with and without dementia and dementia with Lewy bodies. J Neurol Neurosurg Psychiatry 2006; 77:1323.
  148. Cools R, Barker RA, Sahakian BJ, Robbins TW. Enhanced or impaired cognitive function in Parkinson's disease as a function of dopaminergic medication and task demands. Cereb Cortex 2001; 11:1136.
  149. Cools R. Dopaminergic modulation of cognitive function-implications for L-DOPA treatment in Parkinson's disease. Neurosci Biobehav Rev 2006; 30:1.
  150. Mattis PJ, Tang CC, Ma Y, et al. Network correlates of the cognitive response to levodopa in Parkinson disease. Neurology 2011; 77:858.
  151. Okun MS, Tagliati M, Pourfar M, et al. Management of referred deep brain stimulation failures: a retrospective analysis from 2 movement disorders centers. Arch Neurol 2005; 62:1250.
  152. Parsons TD, Rogers SA, Braaten AJ, et al. Cognitive sequelae of subthalamic nucleus deep brain stimulation in Parkinson's disease: a meta-analysis. Lancet Neurol 2006; 5:578.
  153. Aarsland D, Larsen JP, Karlsen K, et al. Mental symptoms in Parkinson's disease are important contributors to caregiver distress. Int J Geriatr Psychiatry 1999; 14:866.
  154. Levy G, Tang MX, Louis ED, et al. The association of incident dementia with mortality in PD. Neurology 2002; 59:1708.
  155. Weintraub D, Moberg PJ, Duda JE, et al. Effect of psychiatric and other nonmotor symptoms on disability in Parkinson's disease. J Am Geriatr Soc 2004; 52:784.
  156. Aarsland D, Larsen JP, Tandberg E, Laake K. Predictors of nursing home placement in Parkinson's disease: a population-based, prospective study. J Am Geriatr Soc 2000; 48:938.
  157. Uc EY, Rizzo M, Anderson SW, et al. Impaired navigation in drivers with Parkinson's disease. Brain 2007; 130:2433.