Parkinsonism and Related Disorders 20 (2014) 1145e1148
Contents lists available at ScienceDirect
Parkinsonism and Related Disorders journal homepage: www.elsevier.com/locate/parkreldis
Montreal Cognitive Assessment for the screening and prediction of cognitive decline in early Parkinson's disease Nagaendran Kandiah a, b, *, Angeline Zhang a, Alvin Rae Cenina a, Wing Lok Au a, b, Nivedita Nadkarni c, Louis Cs Tan a, b a b c
Department of Neurology, National Neuroscience Institute, Singapore Duke-NUS, Graduate Medical School, Singapore Centre for Quantitative Medicine, Duke-NUS, Singapore
a r t i c l e i n f o
a b s t r a c t
Article history: Received 23 April 2014 Received in revised form 12 June 2014 Accepted 4 August 2014
Background: Early diagnosis of cognitive impairment in PD would allow appropriate monitoring and timely intervention to reduce the progression to dementia (PDD). Objective: To study the usefulness of the Montreal Cognitive Assessment (MoCA) in the screening for mild cognitive impairment (PD-MCI) and its predictive utility in determining longitudinal cognitive decline in PD. Methods: Prospective longitudinal study of patients with mild PD. PD-MCI and PDD was diagnosed based on the Movement Disorder taskforce (MDS) criteria. Receiver Operating Characteristic analyses and Cox regression analyses were performed. Results: 95 patients; mean age 66.37 (SD 7.86); mean H&Y score of 1.99 (SD 0.45) were studied. At baseline, 34 patients fulﬁlled the MDS criteria for PD-MCI. MoCA, compared to the MMSE had a high discriminatory power in detecting PD-MCI [Area Under Curve (AUC) of 0.912, p < 0.001]. A MoCA score of 26 provided a sensitivity of 93.1% for the diagnosis of PD-MCI. In the longitudinal cohort over 2 years, baseline MOCA was useful in predicting cognitive decline (AUC of 0.707, p ¼ 0.05). With Cox regression analyses, a 1-point lower score on baseline MoCA was associated with a 34% increased risk of cognitive decline [Hazard ratio (HR) 1.34; 95% CI: 1.03e1.74: p ¼ 0.029]. A baseline MoCA 26 was highly predictive of progressive cognitive decline (HR 3.47, 95% CI: 2.38e5.07; p < 0.01). Conclusions: MoCA is a reliable tool in predicting cognitive decline in early PD. A MoCA score of 26 signiﬁcantly increases the risk for progressive cognitive decline. © 2014 Elsevier Ltd. All rights reserved.
Keywords: Parkinson's disease Dementia Cognitive functions
1. Introduction Mild cognitive impairment in Parkinson Disease (PD-MCI) and dementia (PDD) are highly prevalent and contribute signiﬁcantly to poor quality of life in PD [1,2]. There is growing evidence to demonstrate that even in early PD, there is a high prevalence of cognitive impairment [3e5]. The prevalence of cognitive impairment in early PD has been reported to be as high as 38.2% . It is thus essential that clinicians routinely screen for and manage cognitive impairment in early PD. Its signiﬁcance has been highlighted by various studies and by the Movement Disorders Society
* Corresponding author. National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore. Tel.: þ65 63577171; fax: þ65 63577137. E-mail address: [email protected]
(N. Kandiah). http://dx.doi.org/10.1016/j.parkreldis.2014.08.002 1353-8020/© 2014 Elsevier Ltd. All rights reserved.
(MDS) Task Force on PD-MCI . Risk factors for cognitive impairment in PD include older age, lower education, worse motor scores, rigidity, postural instability, increased daytime somnolence, and cerebral white matter disease [3,6e9]. Cognitive impairment in PD typically involves multiple domains including episodic memory, executive function, working memory/ attention, visuospatial function and psychomotor speed [5,9e14]. Thorough evaluation of these various domains would require comprehensive neuropsychological evaluations as suggested by the MDS taskforce . However in a routine clinical practice, due to time and manpower constraints, it is often not feasible to perform comprehensive neuropsychological evaluations. In these situations, the availability of short, simple and reliable cognitive screening instruments would allow clinicians to screen for cognitive impairment and initiate early pharmacological and non-pharmacological management. Several screening tests including the mini mental
N. Kandiah et al. / Parkinsonism and Related Disorders 20 (2014) 1145e1148
state examination (MMSE) and Montreal Cognitive Evaluation (MOCA) have been reported to be useful for this purpose. The Montreal Cognitive Assessment (MoCA)  has been previously described as a useful screening tool in PD with good discriminant validity [17,18], good inter-rater and intra-rater reliability , good correlation with a neuropsychological battery , and has no ceiling effect, unlike the MMSE [20,21]. Studies thus far describing the usefulness of the MOCA have been largely cross sectional in nature and the utility of the MOCA in predicting longitudinal cognitive decline has not been fully evaluated. The few longitudinal studies investigating the usefulness of the MoCA, were limited by either lack of clinical diagnosis or by lack of neuropsychological evaluations [22,23]. To study the effectiveness of the MOCA for the screening of PDMCI and in predicting longitudinal cognitive decline in early PD, we performed a prospective longitudinal study of patients with mild PD, supported by clinical evaluation and comprehensive neuropsychological assessment. We hypothesized that the MOCA will be effective as a screening tool for PD-MCI and will also be able to predict cognitive decline in early PD. 2. Methods 2.1. Study participants Patients with mild PD presenting at a tertiary neurology centre were prospectively recruited from August 2011 to March 2012. The diagnosis of PD was made by neurologists trained in movement disorders according to the National Institute of Neurological Disorders and Stroke (NINDS) criteria . Only patients with mild PD, having a Hoehn & Yahr (H&Y) stage