Is all cognitive impairment in Parkinson’s disease “mild cognitive impairment”?
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Cognitive impairment can be demonstrated in Parkinson’s disease (PD) from the very beginning of the disease. Clinical manifestations range from slight deficits, only demonstrable by means of neuropsychological testing, up to dementia. If a linear involution is supposed for the cognitive worsening in PD, then the relatively subtle cognitive defects should be taken as the earliest signs of dementia implying that PD-MCI concept would be thoroughly equivalent to that used for the early prediction of other dementias among healthy population. Cognitive defects in PD, however, may not follow a normal distribution. While fronto-striatal deficits, such as working memory, set-shifting and free-recall verbal memory appear altered in most patients during long periods of time, certain functions depending on more posterior-cortical regions, such as copying or naming, usually characterize patients with dementia. Fronto-striatal and posterior-cortical cognitive defects may have a different pathophysiological substrates, evolution and prognosis. While fronto-striatal defects appear more related to dopaminergic defects, posterior-cortical defects may obey multiple neurotransmitter failure. Designing criteria to accurately diagnose PD-MCI is highly relevant for clinical treatment, research, care-giving and decision-making. Besides quantitative defects, an operative definition of MCI in PD should clearly distinguish a “risky cognitive profile” among the broad cognitive defects intrinsic to PD. Thus, along with other possible biological markers, from a neuropsychological point of view, posterior-cortical defects probably represent the very syndrome of MCI in PD.
KeywordsExecutive Mild cognitive impairment Parkinson’s disease Posterior-cortical
- Aarsland D, Bronnick K, Williams-Gray C, Weintraub D, Marder K, Kulisevsky J, Burn D, Barone P, Pagonabarraga J, Allcock L, Santangelo G, Foltynie T, Janvin C, Larsen JP, Barker RA, Emre M (2010) Mild cognitive impairment in Parkinson disease: a multicenter pooled analysis. Neurology 75(12):1062–1069PubMedCrossRefGoogle Scholar
- Dalrymple-Alford JC, Livingston L, Macaskill MR, Graham C, Melzer TR, Porter RJ, Watts R, Anderson TJ (2011) Characterizing mild cognitive impairment in Parkinson’s disease. Mov DisordGoogle Scholar
- Emre M, Aarsland D, Brown R, Burn DJ, Duyckaerts C, Mizuno Y, Broe GA, Cummings J, Dickson DW, Gauthier S, Goldman J, Goetz C, Korczyn A, Lees A, Levy R, Litvan I, McKeith I, Olanow W, Poewe W, Quinn N, Sampaio C, Tolosa E, Dubois B (2007) Clinical diagnostic criteria for dementia associated with Parkinson’s disease. Mov Disord 22(12):1689–1707PubMedCrossRefGoogle Scholar
- Kulisevsky J, Garcia-Sanchez C, Berthier ML, Barbanoj M, Pascual-Sedano B, Gironell A, Estevez-Gonzalez A (2000) Chronic effects of dopaminergic replacement on cognitive function in Parkinson’s disease: a two-year follow-up study of previously untreated patients. Mov Disord 15(4):613–626PubMedCrossRefGoogle Scholar
- Petersen RC, Stevens JC, Ganguli M, Tangalos EG, Cummings JL, DeKosky ST (2001b) Practice parameter: early detection of dementia: mild cognitive impairment (an evidence-based review): report of the quality standards subcommittee of the american academy of neurology. Neurology 56(9):1133–1142PubMedGoogle Scholar
- Riedel O, Klotsche J, Spottke A, Deuschl G, Forstl H, Henn F, Heuser I, Oertel W, Reichmann H, Riederer P, Trenkwalder C, Dodel R, Wittchen HU (2008) Cognitive impairment in 873 patients with idiopathic Parkinson’s disease: results from the german study on epidemiology of parkinson’s disease with dementia (GEPAD). J Neurol 255(2):255–264PubMedCrossRefGoogle Scholar
- Setó-Salvià N, Clarimón J, Pagonabarraga J, Pascual-Sedano B, Campolongo A, Combarros O, Mateo JI, Regaña D, Martínez-Corral M, Marquié M, Alcolea D, Suárez-Calvet M, Molina-Porcel L, Dols O, Gómez-Isla T, Blesa R, Lleó A, Kulisevsky J (2011) Dementia risk in Parkinson disease: disentangling the role of MAPT haplotypes. Arch Neurol 68(3):359–364Google Scholar