Cognitive markers of mild cognitive impairment: An Indian experience

This article is author reply to the ‘’Errors in conducting screening for mild cognitive impairment with HMSE” published in Ann Indian Acad Neurol (2015; 18: 492-3).[1]

Sir,

We thank the readers for their interest in our study and for their valuable opinions.

1. In a case control study (or the retrospective study), in which patients (cases) who have a disease or outcome of interest is compared with controls who do not have the disease or outcome. Researcher look back retrospectively to compare how the risk factor is present in each group to determine the relationship between the risk factor and the disease.

   Our study is not to find the exposure and disease prevalence, but to validate and to see the reliability of the battery developed. Definitely, our study is not related to demonstrate the risk factor associated with the disease (or outcome). Moreover, the normal samples were selected from the community (it is a cross-sectional study) as per the protocol of the study. Hence, this study cannot be a case control study.

2. In our study, the mean value for mild cognitive impairment (MCI) should be 0.59 instead of 0.00. This was a typographical error form our side and we admit the same.

3. We have used Hindi mental State Examination (HMSE) along with the Everyday Abilities Scale for India to identify and screen dementia. Both measures have been adopted and developed for the Indian older adults. We did not use HMSE to identify MCI; rather we used the clinical dementia rating scale and Petersen criteria for MCI. We disagree with the author's suggested algorithm to classify MCI using HMSE (normal cognitive function = 27-30, MCI = 21-26).

Rationale

MCI is a transitional stage between normal aging and screening measures such as HMSE, which may not be sensitive enough to identify or pick up MCI cases. And therefore participants with MCI score normal or near normal on such screen measures, as observed in our study. It has been demonstrated that several factors, such as culture and demographic variables, could affect performance on cognitive task(s). And therefore cutoff value developed by original authors may not be applicable across culture. We need to exercise caution while using and interpreting screening measures especially for our Indian elderly participants. To the best of our knowledge, there is a lack of age- and education-adjusted MMSE/HMSE cutoff value for the Indian older adults. Hence, we would like to recommend future study focusing on the development of longitudinal robust normative data for the Indian participants.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.