Cohort study ON Neuroimaging, Etiology and Cognitive consequences of Transient neurological attacks (CONNECT)

Transient Neurological Attacks (TNAs) are transient neurological signs with
acute onset. These TNAs are common among elderly people. The signs and symptoms
may be focal, like hemiparesis, or non-focal, like acute cognitive complains.
The focal TNAs have an ischemic cause and are therefore referred to as
Transient Ischemic Attacks (TIAs). The cause of non-focal TNAs is unknown.
Recently an increased risk of dementia was found among people with non-focal
TNAs. We know that silent brain infarcts are also common among elderly people
and that these lesions can eventually result in dementia, in particularly if
they are located in eloquent brain areas.
This study should answer the question whether cognitive function declines after
a TNA and whether this decline depends on 1) the kind of TNA (focal or
non-focal) and 2) the presence and incidence of silent brain infarcts on MRI.
Subsequently we aim to study cognitive decline in this population with advanced
MR techniques to assess whether structural and functional connectivity of
neuronal networks in the brain are involved in cognitive decline after a
TNA.

The overall objective of this study is to assess to what extend different
cognitive domains are affected by a recent TNA and which mechanism is
responsible for this cognitive decline. We wanted to know whether the kind of
TNA (focal, non-focal, mixed), presence of vascular risk factors, lesions seen
on conventional MRI, like silent brain infarcts, white matter lesions and
atrophy (in part) determine the risk of cognitive decline. Subsequently we aim
to study the role of structural and functional connectivity of brain networks
in cognitive decline in this particular patient population. Finally we want to
study the causes of non-focal and mixed TNAs.

This is an observational study with a prospective cohort design.

Non contrast enhanced MRI has no known additional risk in patients without
contraindications for MRI (like pacemakers).As part of regular patient care all
potential participants in the study already had one MRI as part of their
clinical work-up. Therefore chance findings (like menigeoma) are unlikely in
this study. Part of the neuropsychological tests are part of regular patient
care. Additional tests in non-demented people are supposed not to be very
aggravating. Currently these tests are used in ongoing large population based
cohort studies.