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Year : 2015  |  Volume : 63  |  Issue : 2  |  Page : 292-

Authors' reply

Syam Krishnan 

Correspondence Address:
Dr. Syam Krishnan

How to cite this article:
Krishnan S. Authors' reply.Neurol India 2015;63:292-292

How to cite this URL:
Krishnan S. Authors' reply. Neurol India [serial online] 2015 [cited 2020 Sep 30 ];63:292-292
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We appreciate the critical comments of the reader regarding our work "Validity of Montreal Cognitive Assessment in Non-English speaking patients with Parkinson's disease". [1] We welcome such healthy discussions and feel that such discussions contribute to the learning of all those who participate.

We would like to answer the reader's second concern first, as the answer to the first concern will be clearer after this. The reader has rightly pointed out the linguistic difference between validity and reliability, which we fully accept. In fact, MoCA-M is both valid and reliable for testing cognition in Malayalam-speaking patients with PD. A good correlation of MoCA-M scores with other established screening (MMSE) and more comprehensive (Addenbrooke's Cognitive Examination- ACE) instruments for cognitive testing supports its validity (the degree to which it measures what it is supposed to measure). The excellent test-retest performance and internal consistency support its reliability (the extent to which it gives results that are consistent or repeatable).

Regarding the reader's first concern about the smaller number of controls-we agree that an equal number of controls would have been ideal. However, we feel that the quality of our results is not compromised by the minimal difference in numbers (60 Vs 70), as the primary aims (testing the metric properties and thereby, validity and reliability of MoCA-M for use in Parkinson's disease patients) of the study do not rely much on the comparison between cases and controls. For the same reason, we are of the opinion that the degree of matching achieved with regard to the age and level of education, mentioned in the first paragraph under "Results" would suffice. The increased risk of cognitive dysfunction in PD patients and the increasing risk with its duration have been established by numerous earlier studies. The significantly worse performance of our PD patients in MoCA-M (paralleling the performance in MMSE and ACE) compared to controls (who were not significantly different from them with regard to age or level of education) thus gives additional support to its validity.


1Krishnan S, Justus S, Meluveettil R, Menon RN, Sarma SP, Kishore A. validity of montreal cognitive assessment in non-english speaking patients with parkinson's disease. Neurol India 2015;63:63-7.