TY - JOUR T1 - Impacts of ‘two-level’ variability on the differential power for Montreal Cognitive Assessment (MoCA) in prodromal dementia JF - Journal of Neurology, Neurosurgery & Psychiatry JO - J Neurol Neurosurg Psychiatry SP - 186 LP - 187 DO - 10.1136/jnnp-2016-314435 VL - 88 IS - 2 AU - Hanna Lu AU - Linda C W Lam Y1 - 2017/02/01 UR - http://jnnp.bmj.com/content/88/2/186.abstract N2 - We read with great interest of the study defining and validating the screening accuracy of short form Montreal Cognitive Assessment (s-MoCA) in individuals with different cognitive status.1 This 5-min s-MoCA is attractive because it achieves the goal for adequate screening of cognitive impairment in an ageing population. Of particular interest, the ‘disease-specific’ versions of s-MoCA enrolling the items from full MoCA, present different classification accuracy.It is noteworthy to postulate that the alternative items between versions of s-MoCA may due to the underlying heterogeneity driven by two-level variability. The first-level is interindividual variability due to the diagnostic classification: mild cognitive impairment (MCI) and dementia refer to a highly heterogeneous community with diverse aetiology, cognitive profiles and clinical outcomes. It is not surprising to find some commonalities given that the underlying neural basis for cognitive impairment in patients with MCI may present with similar impaired cognitive domain … ER -