Brain activity during mental and physical tasks in stroke patients

In the Netherlands each year approximately 36,000 inhabitants have to cope with
the consequences of a stroke. While it is reasonably established that the
overall process of neurological rehabilitation is effective, there is little
evidence to support many specific rehabilitation therapeutic techniques.
Currently it seems that task orientated practice is the most effective single
therapeutic technique. Mental practice (MP) is a promising, task orientated
approach that has been evaluated as treatment techniques in neurological
rehabilitation. It is however difficult to determine whether or not the patient
is actually mentally rehearsing or imagining the movement (MI). Although it is
presently not possible to measure the content of thoughts, it would be very
useful if what the patient is doing during imagery could be quantified more
specifically. Quantified electroencephalographic measurements (QEEG) provide a
way for assessing brain states in relation to movement imagery. The suppression
of mu wave activity (QEEG) during MI is so powerful, that it is currently used
as central parameter for the development of brain computer interfaces. MI is
thought to be related to neural activity of mirror neurons, a subpopulation of
visuomotor neurons that execute analogous information processing in motor
output tasks and the imagination of the same tasks.
To our knowledge, no studies in stroke patients to explore mu wave activity
behaviour during observation, execution and imagery of motor tasks have been
undertaken or published.
It is hypothesized, that mu wave suppression could be a marker for the ability
to consciously imagine and observe movements.

The main aim of the study is therefore to examine mu wave activity during
observation, execution of movements and during movement imagery in comparison
to a passive resting state and active relaxation condition in stroke patients
and matched healthy subjects.

The research design can be described as a cross-sectional study, which will
take place over a one year period from February 2007 until February 2008. The
outcome of QEEG of stroke patients will be compared to the results of healthy
matched subjects.

As there are no invasive interventions, nor any untested experimental
measurement instruments used in this study, there is no additional risk to the
assessment of the patient. The measurements will be carried out in one session
of 1,5 hours.