Dorien Bangma

FDM IN NEURODEGENERATIVE DISEASES | 59 Introduction The ability to make financial decisions in ones' own self-interest is essential for an independent life. Difficulties with financial decision-making (FDM) may lead to financial insecurity, poverty or financial abuse (Lai & Karlawish, 2007; Manthorpe et al., 2012; Okonkwo et al., 2008) and the (early) detection of deficits in FDM is, therefore, of utmost importance. The legislation regarding the mental capacity to make financial decisions differs between countries. In England and Wales, for example, but also in the Netherlands, the law presumes that a person has the capacity to make financial decisions unless this person is deemed to lack this capacity. This means that people with unrecognized or undetected deficits in the capacity to make financial decision can continue to make such decisions even though they may need support. The capacity, or competence, to make financial decisions is an umbrella term that includes not only practical skills and abilities (e.g., counting coins), but also the ability to judge and make (complex) decisions (American Bar Association Commision on Law and Aging and American Psychological Association [ABA/APA], 2008). FDM encompasses various cognitive functions (Glimcher, 2014) and appears to rely on the integrity of the frontal cortex (Kennerley &Walton, 2011). Cognitive functions found to be related to decision-making in general include working memory, executive functioning and numeracy (Chen et al., 2014; Martin et al., 2012; Reyna et al., 2009). Neurodegenerative diseases (NDDs; e.g., Alzheimer’s disease (AD), Parkinson’s disease (PD) or Huntington’s disease (HD)) are characterized by a progressive decline of cognition and neuropsychiatric disturbances (American Psychiatric Association, 2013; Hardiman & Doherty, 2016), which makes people living with an NDD particularly vulnerable for difficulties with FDM. Indeed, research using self or proxy reported questionnaires showed that people living with an NDD have more difficulties in ‘financial skills’ or ‘financial management’ than healthy controls (Pérès et al., 2008; Wadley et al., 2003; Wicklund et al., 2007). Even years prior to the diagnosis of AD (Pérès et al., 2008) and HD (Beglinger et al., 2010), people living with these conditions report more difficulties with FDM compared to healthy controls. Self-report questionnaires, however, rely strongly on an adequate insight into everyday functioning and might, therefore, be less reliable (Wadley et al., 2003). Furthermore, people living with an NDD with comorbid depression tend to report significantly more problems with cognitive functioning in everyday life than people living with an NDD who are not depressed, even when no effects of depression on the performances on performance-based neuropsychological tests are found (Koerts et al., 2012; Marino et al., 2009; Middleton et al., 2006). Finally, previous research has shown that questionnaires often do not give a good reflection of what is measured with performance-based standardized neuropsychological tests (Fuermaier et al., 2015; Koerts et al., 2012; Toplak et al., 2013). In contrast to self or proxy reported questionnaires, performance-based tests directly examine an individual's performance on tasks or during activities using standardized scoring procedures (Engel et al., 2016; Moore et al., 2007). Performance-based tests are frequently administered in an experimental or clinical environment and provide a practical and adequate alternative for real life observations (Moore et al., 2007). Therefore, in order to ascertain in a reliable and valid manner to what extent people