YOD-RiSoCo: Social Cognition and Risk-taking Behaviour in Patients with Young-onset Dementia

Young-onset Dementia (YOD) refers to dementia with the onset before the age of
65 years. A common type of YOD is frontotemporal dementia (FTD), but there can
also be young onset subtypes of Alzheimer*s disease, as well as many other
different subtypes. Characteristic of YOD is that impairments in language,
perception or (social) behavioural changes are usually more prominent in the
early disease stages than memory impairments, which are the hallmark of late
onset dementia, in particular Alzheimer*s disease. These non-memory symptoms
are often under-recognized, which delays the diagnosis of YOD and consequently
contributes to a much more difficult situation for both patients and their
close others. An important affected domain in various subtypes of YOD, is
social cognition (SC). SC refers to the capacities that enable adequate social
behaviours and interactions and includes aspects such recognition of other
person*s emotional expressions, the ability to experience emotions, empathy and
perspective-taking or theory of mind (ToM). SC is underpinned by
frontal-subcortical networks, which are affected in specific subtypes of YOD,
in particular in frontotemporal dementia and behavioural variant of Alzheimer*s
disease. Similar, impairments in social cognition are also found in patients
with other neurological disorders that mainly affect frontal-subcortical
networks, such as severe traumatic brain injury (TBI) or frontally located
brain tumours.
A major characteristic of impaired SC is emotional flattening. Patients
experience no or less (bodily feelings of) emotions. Being able to feel one*s
own emotions is a prerequisite for emotional empathy, since the ability to
empathize with others involves sharing feelings. Such an inability to detect
emotional signals, for instance feelings of fear, that indicate danger during
decision-making, or to take other people*s feelings and perspective into
account is likely to result in inadequate, inappropriate or even problematic
social behaviour, so called *behaviours of concern*, which are potentially
harmful to other people, such as aggression or unsafe driving.
At present there are only a few neuropsychological tests available that measure
aspects of SC. Even more so, tests that reliably measure the abilities to feel
emotions, to have empathy with others and to take others* emotions and
perspective into account in situations involving the safety of other people,
are still lacking. Hence, there is a large unmet need for better
neuropsychological measures of social cognition that are sensitive to these
impairments in emotional feelings and empathy (indicating possible risk of
behaviours of concern). Having such measures available will also likely allow a
more timely diagnosis of the specific behavioural subtypes of YOD.

The overarching aim of this study is to develop new, sensitive measures for
aspects of social cognition (emotion experience, empathy and affective theory
of mind), that will contribute to a better and earlier diagnosis of specific
subtypes (the behavioural variants, bv) of YOD. To this end, the first step is
to assess the sensitivity of the newly developed measures for these aspects of
social cognition, by comparing the performance of patients with a bvYOD
diagnosis to the performance of healthy controls. In addition, construct
validity will be investigated by relating performance on the new SC tests to
existing social cognitive tests (convergent validity) and other general,
non-social cognitive tests measuring for example memory, information processing
speed and attention (divergent validity).
In a second, smaller sub-study, it will be explored whether the new tests are
also ecologically valid, that is, are related to unsafe, risk-taking behaviour
in real life situations. To this end, we will make use of driving simulator
scenarios created to elicit risk-taking behaviour, and to simulate a real world
environment, without the unwanted possibility of eliciting risk-taking
dangerous behaviours in real world situations. The aim of this sub-study is to
investigate whether impaired performance on the new SC tests is related to
risk-taking behaviour. First, this will be analysed in patients already
diagnosed with bvYOD, but also in other patients with frontal damage, to
investigate whether this relation is generic (with the future purpose that the
tests may be broader applicable in the future than only for the diagnosis of
YOD). Second, to investigate whether this relationship is specific, patients
with non-bvYOD variants will be included in the analyses, for whom no SC
impairments or risk-taking behaviour are expected.

This study is designed as an observational and experimental case-control study.

There are no direct benefits for the patient. A potential risk is simulator
sickness (similar to car sickness) during the driving simulator test.
Participants are notified of this possibility beforehand and will be monitored
during the test. They will also be informed of their right to stop the test at
any time. A general risk is that assessments (neuropsychological assessment and
driving simulator assessment) can be too demanding for patients; however,
neuropsychologists carrying out the assessments are experienced in testing
vulnerable patients and will carefully monitor whether the assessments are too
demanding, and quit if necessary.