Errors in conducting screening for mild cognitive impairment with Hindi mental state examination

Sir,

This is with reference to the article entitled “Neuropsychological markers of mild cognitive impairment: A clinic based study from urban India” published in Ann Indian Acad Neurol (2015; 18: 177-80).[1] The authors deserve appreciation for their effort. However, I have a few concerns with this study. The authors stated that it was a cross-sectional study and 42 participants [22 patients with mild cognitive impairment (MCI) and 20 normal controls (NCs) between the age of 60 years and 80 years] were chosen for the purpose of this study.[1] This statement in itself appears incorrect. A cross-sectional study (also known as prevalence study) is different from a case-control study (also known as case-reference study). Therefore, the usage of these terms is not interchangeable and cannot be used in this manner. Then the authors went on to write that the 22 individuals with MCI and 20 NCs were matched for age and education. This makes the study a matched case-control study and not a cross-sectional one. Importantly, the authors do not seem to have age-matched the individuals with MCI with the NCs. If the authors had individually matched the age, the number of individuals in the two groups would have been similar (20 individuals with MCI and 20 NCs) and not dissimilar (22 individuals with MCI and 20 NCs), as was the case in this study.

This takes me to my second concern with the study. The authors presented the demographic characteristics of those with MCI and the NCs in Table 1 (reproduced below). A look at the table shows that the mean on the Everyday Abilities Scale of India for MCI is 0.00 and the mean for NC is also 0.00. Surprisingly, the statistical analysis performed on this (mean for MCI and the mean for NC) has a P value of 0.9, which is not possible. This needs a relook on the part of the authors.

Table 1.

Table showing the demographic characteristics of the study sample

Lastly, the authors stated that all the study participants were screened with the Hindi mental state examination (HMSE) and Everyday Abilities Scale of India. I am unable to understand the role of screening patients with HMSE. This screening has been conducted on all 42 study participants without assigning a specific role for this screening. The group MCI scored a mean of 28.00 (2.37) while the group NC scored a mean of 30.00 (1.00). The HMSE is a Hindi version of the mini-mental state examination (MMSE) and uses the same cutoffs for the assessment of cognitive impairment as MMSE (original version).[2] The authors of MMSE recommend that the following cutoff levels be used for classification purposes: Normal cognitive function = 27-30 and MCI = 21-26. Now, if a study participant is defined as normal in the screening test, how could he/she be included in the MCI group?

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