Huntington’s disease (HD) is an autosomal, dominant inherited neurodegenerative disorder, characterized by a triad of symptoms including motor abnormalities, behavioral symptoms and cognitive... Show moreHuntington’s disease (HD) is an autosomal, dominant inherited neurodegenerative disorder, characterized by a triad of symptoms including motor abnormalities, behavioral symptoms and cognitive decline. As exact knowledge of the course of cognitive decline and the underlying cause of developing apathy is still lacking in HD, the primary aim of this thesis was to gain further insight into the cognitive profile and apathy in Huntington’s disease (HD). We aimed to evaluate whether the most commonly used participant classification makes a useful distinction between HDGECs and whether these groups are homogeneous by giving an overview of the participants’ characteristics at the largest REGISTRY HD center (chapter 2). In chapter 3, we aimed to map the cognitive profile in different disease stages, and to evaluate whether CAG length mediates cognitive decline in HD (chapter 3). In addition, we explored whether there is a difference in cognitive performance between individuals taking medication targeting non-cognitive neuropsychiatric signs or/and tetrabenazine and non-users in HD (chapter 4). In chapter 5, we aimed to relate apathy to the neurodegenerative process in HD. In chapter 6, we evaluated whether HDGECs and their proxies agree on the degree of apathy by using a self-report questionnaire. Show less