Somatosensory deficits after stroke

The somatosensory system is important for many common everyday activities and
informs the brain about the position of different parts of the body. When this
information about the representation of the body is processed, it not only
allows recognition of body parts, but also allows to move within and act upon
the environment. These processes are higher order, cognitive aspects of the
somatosensory system. Somatosensory deficits after stroke are common and
related to a longer length of stay and lower activity levels during
rehabilitation. However, extensive neuropsychological somatosensory functioning
after stroke is only rarely assessed. As a result, knowledge about the
occurrence of these deficits, their underlying neurological substrates as well
as the influence of these deficits on outcome remains unclear. The overall aim
of this study is to increase our understanding of the cognitive processes, the
underlying neuroanatomical substrate and its recovery processes of higher order
somatosensory deficits after stroke. This may provide new opportunities for
development of rehabilitation programs.

There are two objectives for this study.
1. To investigate the frequency of somatosensory deficits in the early and
chronic stage of stroke patients.
2. To understand the nature and the neuroanatomical correlates of specific
higher order somatosensory deficits

This is a longitudinal observational study in which a battery of validated
non-invasive neuropsychological tests will be administered to look into
somatosensory functioning in the early and chronic phase of patients with a
stroke. In addition, other cognitive domains that are associated with
somatosensory functioning such as visual perception, language, executive
functioning and memory are also assessed, to control for interference of other
cognitive domains. The aim of the study is to investigate the frequency and the
course of somatosensory deficits after stroke. In addition, the nature and
underlying neurological substrate of higher order somatosensory deficits will
be investigated.
This study will be performed on 60 hospital-based patients in the early phase
after the diagnosis of a stroke in the University Medical Center Utrecht
(UMCU). To minimize the burden for the participants, data collected by a
standard 'care as usual' neuropsychological assessment will be used for the
patients hospitalised in the UMCU. This standardised neuropsychological
assessment already tests several cognitive domains, including visual
perception, language, executive functioning, memory and also includes a short
screening on somatosensory functioning. This neuropsychological assessment is a
standard procedure and is administered in all ischemic stroke patients. In case
patients show deficits on the initial short somatosensory screening or report
complaints in the somatosensory functions (for example, show a decreased sense
of touch or report problems in recognizing one's own arm of hand), we propose
to conduct an elaborate somatosensory testbattery targeting the full
somatosensory domain which also include tasks for higher order somatosensory
functions. Finally, all participants who underwent an elaborate somatosensory
assessment will be tested for a follow-up assessment after six months to
explore the course of the deficits.

The patient is asked to concentrate for 90 minutes of testing in the early
phase after stroke and 2 hours of testing after 6 months on tests that examines
cognitive functions. The tests are all standardised pen- and paper test that
are designed for a clinical population. However, a posiible burden for the
patients might be fatigue due to concentration. To diminish the fatigue,
several breaks are included. Previous studies which are comparable with respect
to nature and testmaterial did not have shown any adverse effects or complaints
(for example, the study with protocolnumber 05-109 "Perception and action in
the somatosensory system")