Géraud Dautzenberg

Chapter 5 114 spending resources wisely is as important, giving the ones the most in need priority (Alzheimer’s Disease International 2018; Borson et al., 2013). This implies that patients at highest risk (taking into account the age or speed of onset in combination with the degree of impairment) should be referred for an elaborate specialised diagnostic route. The cognitive functioning of patients considered to be at lower risk (e.g., with psychiatric disorders) should be assessed in the best available way, depending on the resources. When the scarce and time-consuming gold standard i.e. an NPA, is less available the assessment of the cognitive functions could be done with a short, validated test. In our opinion, this should include reassessment with this test, as it is easy to perform and takes limited time to administer, i.e., active monitoring. Therefore, it is important to use screening instruments that can detect both MD and MCI. The Montreal Cognitive Assessment (MoCA) was developed as a short screening tool for MCI and MD (Nasreddine et al., 2005) and validated in at least 35 different languages and even more settings. Most of these studies can be found on the MoCA-test website (mocatest.org). At the original proposed cut-off of <26, the sensitivity for correctly screening patients with MCI (90%) and MD (100%) is very good (Nasreddine et al., 2005). Although it has been repeatedly shown to be superior to the MMSE in identifying MCI (Folstein, et al., 1975; Pinto et al., 2019), the MoCA still has its limitations as a triaging tool. Its ability to identify people with NoCI (specificity) is criticised in clinical practice because specificity varies due to clinical and demographic reasons (Davis et al., 2015). Frequently reported examples are age, education, rural environment, ethnic or cultural background (including race in some countries), substance abuse and psychiatric diseases (mocatest. org). It is repeatedly suggested to lower the cut-off with higher specificity as a result (O’Driscoll and Shaikh, 2017; Carson et al. 2018;Dautzenberg et al., 2020). Nevertheless, the MoCA with a lower cut-off is still not suitable for identifying MD as a stand-alone assessment of referred patients to an old age psychiatric clinic (Dautzenberg et al. 2020; Korsnes, 2020), or as an assessment of referred patients to its memory clinic (Smith et al. 2007; Dautzenberg et al., 2021) because the positive predictive value (PPV) is never sufficient (Carson, et al., 2018). Its high sensitivity makes it a good screener, finding most MD patients. The high negative predictive value (NPV) for appropriately discharging NoCI patients, is promising, although for triaging those who need a scarce NPA, moderate specificity gives too many false positives (FPs). Double cut-offs are reported in the literature as a solution by using one threshold for health and one for disease (Batelaan et al., 2007; Swartz et al., 2016; Landsheer, 2020; Thomann et al., 2020). Especially where classifications create subthreshold disorders,

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