Carolien Zeetsen

55 CHAPTER Validating the MoCA in addiction health care 3 Discussion This study is the first to examine the MoCA as a short cognitive screen in a sample of patients with SUD, using an extensive NPA as benchmark. The results show that administration of the MoCA at baseline resulted in a worse validity than the MoCA administered at follow–up. Also, while at follow–up all MoCA–DS correlated with the corresponding domain of the NPA, at baseline only the MoCA–DS executive functioning, abstract reasoning, and memory significantly predicted NPA performance eight weeks later. These findings are partly in line with other MoCA studies (Wester et al., 2013; Oudman et al., 2014; Alarcon et al., 2015) where only Alarcon et al. (2015) reported a higher predictive validity. There are, however, important differences between these studies and the current. First, only homogeneous groups of patients with AUD were included in previous studies, limiting their external validity. Second, patients in those studies were abstinent for at least one week (Alarcon et al., 2015) to a minimum of six months (Oudman et al., 2014), while in clinical practice patients are often not abstinent at intake. To date, only one study in AUD related MoCA performance directly to an NPA (Ewert et al., 2018), which is considered to be the gold standard for the assessment of cognitive impairments (Lezak et al., 2012). Ewert et al. (2018) found a higher education–adjusted cut–off score than was currently found to be indicative of cognitive impairment, using a homogeneous group of hospitalized patients with AUD. The only study in a heterogeneous group of patients with SUD (Copersino et al., 2009) was more in line with the present findings – albeit that slightly better psychometric properties were found. Regarding the relation between MoCA–DS at baseline and NPA domain performance at follow–up, caution should be taken when interpreting the MoCA–DS. This is in line with a previous study also showing MoCA–DS to be poor predictors of impairment on neuropsychological tests (Moafmashhadi & Koski, 2013). The difference in findings between the predictive and concurrent validity can be explained by the interval between baseline and follow–up. Abstinence could also be an explanation as cognitive recovery is likely to occur with sustained abstinence in AUD (van Holst et al., 2011; Stavro et al., 2013), cannabis (Lyons et al., 2004), and stimulants (Iudicello et al., 2010; Vonmoos et al., 2014; Wood et al., 2014; Zhong et al., 2016). Although more patients were abstinent at follow–up, we did not find a significant effect of abstinence on MoCA performance in our statistical model. There are several strengths to the current study. First, the heterogeneity of the sample largely represents clinical practice, which makes the results generalizable to addiction health care. Second, the used adjustment method for level of education (based on Chertkow et al., 2011) is more fine–grained than the original adjustment method by Nasreddine et al.