Novel methods for function mapping and BCI in children

Each year, a number of patients with refractory epilepsy are implanted with
subdural strips and grids of electrodes (ECoG) or with depth electrodes
(stereo-EEG) in order identify the epileptogenic focus and to determine whether
this region can be surgically resected without loss of essential function. In
the last years, a great portion of the scheduled patients are children, because
they have a lot to gain by early resection of the epileptic focus (Spencer and
Huh, 2008; Maehara et al., 2002). At the UMC, more than 70% of children treated
are seizure free after 1 year. The neuronal signals measured using intracranial
electrodes are of very high quality because of the direct contact between the
neural tissue and the measuring electrodes, and are therefore highly suitable
to answer a wide range of fundamental and applied neuroscientific questions,
such as the mapping of brain functions and the development of assistive
technology known as Brain-Computer Interfaces (BCIs). In the current proposal,
we address these two topics in this population of patients, yielding two
primary objectives.

In the current proposal, two primary objectives will be addressed. The first is
to establish the spatial correspondence between fMRI, ECoG/stereo-EEG and ECS
for different brain functions in children. The second is to investigate the
feasibility of an ECoG/stereo-EEG-BCI for children.

Subjects will be included in an observational study.

There are no known risks associated with fMRI acquisition. The technique does
not require administration of any contrast agent or ionizing radiation. The
fMRI procedure is painless. Slight discomfort may occur due to lying still with
the head and part of the body confined in a tunnel-like device. There are no
known risks associated with performing tasks during ECoG/stereo-EEG recordings.
Implantation of electrodes does carry a risk which is taken into account in the
clinical decision to operate. The present study does not add to that risk, as
the grids are implanted purely for diagnostic purposes. The tasks are much like
simple computer tasks or watching videos for children, and as such pose a
minimal additional burden. No direct benefits are expected for the subjects of
the current study. If results are positive, they are expected to form the basis
for alternative, fast, and patient-friendly methods of functional mapping (as a
manner to guide or eventually replace ECS), suitable for children of the same
population (refractory epilepsy).