Neuropsychological Studies in older adults: A comprehensive MMSE-MoCA conversion table – Prevention of postoperative delirium – Cognitive sequelae of atrial fibrillation

As life expectancy increases, so does the proportion of elderly individuals in most industrialized countries.
As people age, they undergo both physical and cognitive changes. Thus, cognitive difficulties and other agerelated
pathologies such as cardiovascular and neurological diseases increase with age. In this context, atrial
fibrillation (AF) and delirium are of great clinical relevance not only because of their epidemiological data
but also, in particular, because of their major role in the development of cognitive dysfunction. Hence,
sufficient knowledge and identification of potential risk factors of AF and delirium as well as early
recognition are essential to take preventive measures. The present doctoral thesis aims to define
corresponding scores for two widely used cognitive screening tools and provide insights into cognitive
changes in elderly adults with atrial fibrillation and the validity of a preexisting preoperative delirium
prediction model after cardiac surgery.
In study I, a comprehensive conversion table of two commonly used cognitive screening tests was
created. We could define corresponding scores for the Mini-Mental Status Examination (MMSE) and the
Montreal Cognitive Assessment (MoCA) in 803 German-speaking Memory Clinic outpatients. Further, a
systematic review of existing MMSE-MoCA conversions was conducted to create a comprehensive
conversion table. This enables a direct comparison of cognitive test scores at screening examinations and
over the course of disease in patients with predominantly neurocognitive disorders.
Study II investigated the associations between AF and cognition in aging. A small, constant
increase in cognitive functioning over a median duration of 3.97 years in AF patients was found, presumably
explained by learning effects that were less pronounced in non-paroxysmal AF patients, specifically in
processing speed and executive functions. Some evidence suggests diabetes, history of stroke/transient
ischemic attack (TIA) and depression being associated with faster cognitive decline in AF patients.
In study III, an independent external validation of an existing preoperative risk prediction model
for delirium was provided in 348 patients who had undergone cardiac surgery. The evaluated predictive
model showed poor discriminative capacity but fair calibration. As an outlook, reflections on future
directions concerning the role of cognitive performance in AF and delirium are given as well as discussed.