PRediction Of Cognitive Recovery After Stroke: a role for new MRI modalities in daily clinical practice?

Every day, in the Netherlands, about 100 persons are struck by an ischemic
stroke, with huge physical, psychological and financial impact on patients and
society. Cognitive dysfunction affects up to 70% of patients. About half of
them will manifest (partial) recovery, but the others are left with sequelae or
even deteriorate. This is a key aspect of long-term outcome because of its
negative impact on independent daily life functioning, social reintegration and
quality of life. The spectrum of ischemic strokes impacting cognition is
wide:it ranges from extensive cortical to small lacunar infarcts. Particularly
in the elderly a stroke may add to the burden of pre-existing vascular and
degenerative pathologies, thus increasing the chance of cognitive deficits.
Cognitive deficits after stroke can easily be missed in the acute stage,
especially in patients with minimal motor impairments and no language problems
(*the walking and talking patient*). Therefore, cognitive screening is
performed in all patients at our stroke-unit. It improves guidance of patients
and the planning of rehabilitation. However, the predictive value of this early
screening for long-term cognitive outcome is limited. A better prediction of
the cognitive status later on is needed to improve prognostic information for
patients and a more tailored allocation of rehabilitation facilities.
Large cohort studies have identified predictors of cognitive function in the
long term after stroke, e.g. age, location and size of the infarct, premorbid
status, cognitive function in the acute stage, but individualized prediction of
cognitive outcome using these clinical parameters is imprecise. New imaging
techniques have come forward that not only allow a precise localization of the
lesion but also provide detailed individualized information about the
structural cerebral networks involved in various cognitive functions. From a
conceptual viewpoint it is likely that the extent to which a lesion disturbs
the networks that are responsible for the main flow of information through the
brain would be a key determinant of functional deficits and recovery,with an
important potential to improve prediction on top of existing clinical
parameters.Up till now these techniques have been explored in experimental
designs but have not been evaluated in daily clinical practice.
In the present project we will establish the feasibility and value of
integration of these new imaging techniques in daily
clinical practice in a dedicated stroke clinic in order to predict cognitive
outcome one year post stroke.

1: determine the additional predictive value of MRI measures of brain
connectivity on top of existing clinical parameters for cognitive recovery or
deterioration in the first year after stroke.
2: assess feasibility of a standardized work*up including cognitive evaluation
and advanced brain MRI in daily clinical practice in a dedicated stroke clinic.
3: determine the relation between rehabilitation treatment and cognitive
outcome.
4: determine whether measures of functional connectivity obtained with EEG and
measures of structural connectivity obtained with MRI-DTI correlate.

Longitudinal observational prospective cohort study in which the feasibility of
a standardized work*up including formal cognitive assessment and advanced brain
MRI in daily clinical practice will be established and its additional value in
predicting cognitive outcome, improvement, no improvement or deterioration,
after one year is evaluated
After informed consent, participants will undergo formal neuropsychological
tests within a range of 3-6 weeks post stroke, according to a standardized 60
minute protocol for vascular cognitive impairment. Patients will be graded as
non*impaired or having a mild or major vascular cognitive disorder according to
the VasCog criteria.
For all participants a 3Tesla MRI scan will be acquired within a range of 3-6
weeks after stroke. Infarct volume and location, as well as brain volumes will
be assessed. Networks will be reconstructed with state of the art fiber
tractography and processing techniques. Furthermore, the first 40 successive
participants from the cognitive impaired group and the first 20 successive
participants in the reference group will undergo an EEG within the same
timeframe of 3-6 weeks after stroke. Participants will be asked permission for
assessment of their apolipoprotein *4 status. Moreover, emotional functioning
and physical activity will be assessed. 3 months after stroke participation,
self-efficacy, cognitive complaints and quality of life will be assessed, as
well as the type of rehabilitation, functional outcome and medication use. 6
months after stroke again the type of rehabilitation, functional outcome and
medication use will be ascertained.
At one year after stroke again patients will undergo the neuropsychological
test battery. Moreover, participation, functional status, emotional
functioning, self-efficacy and quality of life will be assessed.
Clinical variables, cognitive function in the acute stage and imaging
parameters will be used to predict cognitive status at one year. If the above
mentioned will prove to be feasible, we will implement the results at the
stroke unit of the Elisabeth Tweesteden Hospital and validity of the prediction
algorithm will be tested in a new prospective cohort.
As a reference group, 60 patients without a vascular cognitive disorder will be
included. This group will be matched for age, sex and level of education. The
course of cognitive deterioration or recovery and the MRI results will be
compared with this reference group.

Clinical examination, laboratory testing, cognitive screening and admittance to
our dedicated stroke unit are part of the standard evaluation of patients
suffering from a stroke. In approximately 50% of the stroke patients, MRI
scanning is part of the workup. In the context of this study all patients will
undergo an MRI-scan. The additional burdens that are required for this study
are undergoing a neuropsychological assessment and filling out several
questionnaires. Furthermore, patients are required to undergo another
neurological examination one year post stroke. MRI-scanning has proven to be
safe, reliable and non-invasive. It is usually well tolerated. An EEG is a non
invasive and painless examination with a duration of 20 minutes.