Abstract
BackgroundCognitive impairment is a common feature of Parkinson's disease (PD). The diagnoses of mild cognitive impairment (MCI) in patients with PD implies an increased risk for later development of dementia, however, it is unclear whether a specific type of cognitive loss confers increased risk for faster cognitive decline.ObjectiveDetermine whether it was possible to identify distinct cognitive phenotypes in a sample of patients with PD.MethodsA cross-sectional evaluation of 100 patients with PD recruited from a movement disorders clinic was conducted. The patients were evaluated using the simplified motor score of the UPDRS, the Hoehn and Yahr, Schwab and England, Geriatric Depression Scale, Pfeffer Functional Activities Questionnaire, Clinical Dementia Rating Scale, Mini-Mental State Examination, clock drawing test, digit span, word list battery of CERAD, Frontal Assessment Battery and verbal fluency test. We classified the patients as having normal cognition (PDNC), MCI (PDMCI) or dementia (PDD). Data were analyzed using the chi-square test, non-parametric statistics and cluster analysis.ResultsThere were 40 patients with PDD, 39 with PDMCI and 21 with PDNC. Patients with PDD were older, had longer disease duration, lower education and lower MMSE scores. Cluster analysis showed 3 general distinct cognitive profiles that represented a continuum from mild to severe impairment of cognition, without distinguishing specific cognitive profiles.ConclusionCognitive impairment in PD occurs progressively and heterogeneously in most patients. It is unclear whether the definition of the initial phenotype of cognitive loss can be used to establish the cognitive prognosis of patients.
Highlights
Cognitive impairment is a common feature of Parkinson’s disease (PD)
Patients were classified as having normal cognition (PDNC), mild cognitive impairment (MCI) (PDMCI) or dementia (PDD) according to MDS diagnostic criteria.[16,17]
The clinical evaluation led to the diagnosis of PDD in 40 patients (40%), PD-MCI in 39 patients (39%) and patients were classified as having normal cognition (PDNC) in 21 patients (21%) (Table 1)
Summary
Cognitive impairment is a common feature of Parkinson’s disease (PD). Many patients present with mild cognitive impairment (MCI) even at disease onset and most develop dementia during the course of the disease.[1,2] Cognitive decline has a negative impact on the quality of life of patients and caregivers, increases the risk for institutionalization and death, and significantly increases the costs of the disease.[3,4,5] There are many risk factors associated with cognitive decline in PD, including age, duration of disease, severity of motor symptoms and the diagnosis of MCI.[6]MCI in patients with PD has a cross-sectional prevalence of around 25%, and patients with PD may present impairment in many different cognitive domains such as attention, memory, visuospatial function, executive function and language.[7,8] The clinical presentation of MCI in PD varies widely, and there is substantial variation in the progression of cognitive deficits across patients.[2]. The diagnoses of mild cognitive impairment (MCI) in patients with PD implies an increased risk for later development of dementia, it is unclear whether a specific type of cognitive loss confers increased risk for faster cognitive decline. We classified the patients as having normal cognition (PDNC), MCI (PDMCI) or dementia (PDD). Cluster analysis showed 3 general distinct cognitive profiles that represented a continuum from mild to severe impairment of cognition, without distinguishing specific cognitive profiles. Conclusion: Cognitive impairment in PD occurs progressively and heterogeneously in most patients. It is unclear whether the definition of the initial phenotype of cognitive loss can be used to establish the cognitive prognosis of patients.
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