This thesis investigates different aspects of apathy - as a distinct clinical syndrome assessed with the Apathy Scale- in older persons with and without concurrent depression. In Chapter 2,... Show moreThis thesis investigates different aspects of apathy - as a distinct clinical syndrome assessed with the Apathy Scale- in older persons with and without concurrent depression. In Chapter 2, clinically relevant subtypes of apathy according to the Apathy Scale in older persons from the PROMODE study are examined, using data-driven Latent Class Analysis (LCA). Further, specific characteristics across the classes identified by LCA are investigated. Then, in Chapter 3, cross-sectionally the prevalence, severity and clinical profile of apathy in depressed and non-depressed older persons, in relation to various possible determinants is described. Chapter 4 examines which characteristics predict, over a 2-year period, the incidence and course of apathy in at baseline depressed older persons from the NESDO study. Chapter 5, using data of the NESDO and NESDA, investigates the presence of apathy in late-life compared to early-life depression, and various determinants of clinically relevant apathy in older compared to younger depressed persons. In Chapter 6 the association of the presence of apathy among community-dwelling older persons from the PROMODE study and a diminished quality of life is examined. All results are placed a current perspective in Chapter 7 that also discusses clinical implications, and makes some recommendations for future research. Show less
The locus coeruleus (LC) is a nucleus in the brainstem, and projects widely to the forebrain where it releases norepinephrine (NE). Catecholamines such as NE do not have a unitary effect on their... Show moreThe locus coeruleus (LC) is a nucleus in the brainstem, and projects widely to the forebrain where it releases norepinephrine (NE). Catecholamines such as NE do not have a unitary effect on their target neurons, but instead influence the function of other neurotransmitters, a process that is known known as neuromodulation. By virtue of the LC’s wide projection profile and the neuromodulatory properties of NE, the LC-NE system profoundly influences neural firing characteristics and associated cognitive processes. The work presented in this thesis addresses the role of the LC-NE system in various aspects of human cognition, and the modulation of brain state. Show less
This thesis describes several state-of-the-art challenge methods to study the cholinergic system in humans by measuring the effects of compounds that selectively act upon muscarinic or... Show moreThis thesis describes several state-of-the-art challenge methods to study the cholinergic system in humans by measuring the effects of compounds that selectively act upon muscarinic or nicotinic acetylcholine receptors. The thesis reveals part of the complexity of the cholinergic system, its changes related to aging, its relationship with cognitive function and performance, and its role in inflammation. Additionally, the methodology described in the thesis provides controlled circumstances using repeated measurement of drug concentrations and effects during a pharmacologic cholinergic challenge that can be used in drug development of new compounds with cholinergic activity. Show less
The overriding aim of my thesis was to study the relationship between blood pressure (BP) and cognitive and psychological functioning in older persons. Observational studies indicate that lower BP... Show moreThe overriding aim of my thesis was to study the relationship between blood pressure (BP) and cognitive and psychological functioning in older persons. Observational studies indicate that lower BP increases risk for cognitive decline in older persons. Older persons are at risk for impaired cerebral autoregulation, and lowering their BP may compromise cerebral blood flow and cognitive function. Contradictory to our hypothesis, the Discontinuation of Antihypertensive Treatment in Elderly people (DANTE) Study Leiden, a community-based randomized clinical trial in older persons (aged ≥75 years) with mild cognitive deficits, did not show that discontinuation of antihypertensive treatment improves cognitive functioning. The lack of the effect of this trial may be due to the unintentional inclusion of persons with a relatively intact cerebral autoregulation. Furthermore, we demonstrated that older persons with mild cognitive deficits and with orthostatic hypotension, who discontinued all their antihypertensive medication had an increased probability of being free from orthostatic hypotension 4 months later, compared to persons who continued their medication. Finally, in the DANTE MRI sub study, the relationship between BP and both conventional features of small vessel disease (SVD) and microstructural damage was explored, as well as the relation between microstructural damage and cognitive and psychological dysfunction. Show less
