Brain–Computer Interfaces - Index of

166 N. Birbaumer and P. Sauseng
Neuroelectric responses can not be perceived neither consciously or unconsciously
because the central nervous system does not seem to have specific receptors for
its own activity such as peripheral organ systems. Brain perception analogous to
visceral perception (see [1]) is not possible for neuroelectric activity but seems to
be possible for brain vascular responses. Magnetic resonance imaging scanners are
extremely expensive and routine clinical training over longer periods of times necessary
for the treatment of emotional or cognitive disorders is not within reach using
functional magnetic resonance imaging. Near Infrared Spectroscopy (NIRS) may
serve as a cheap and non-invasive alternative to fMRI. Near Infrared Spectroscopy
uses infrared light from light sources attached to the scalp and measures the reflection
or absorption of that light by the cortical tissue, which is largely dependent
on the oxygenation and deoxygenation of cortical blood-flow. Devices are commercially
available and relatively cheap, and a multitude of channels can be recorded.
Essentially the response can be compared to the BOLD response insofar as the
consequences of neuronal activity are measured by changes in blood-flow or vascular
responses. Therefore, rapid learning was described in the first study published
on a NIRS-BCI [33]. Subjects were able to increase or decrease oxygenation of
their blood in the somatosensory and motor areas of the brain in healthy subjects
using mainly motor imagery. Localised blood-flow was achieved by imagining contralateral
hand activity. Future studies will show whether NIRS-BCI can be used
for clinical application, particularly emotional disorders in children and adolescents
should respond positively to NIRS training. A first controlled trial for the treatment
of fronto-central connectivity using NIRS-BCI in attention deficit disorder is on the
way in our laboratory.
6 Future of BCI in Neurorehabilitation
The future of BCI in neurorehabilitation depends more on psychological, sociological
and social political factors than on new technology or better algorithms for
the decoding and classification of brain activity. This will be illustrated with brain
communication in amyotrophic lateral sclerosis:
Despite the obvious visibility and success of BCI in ALS patients, 95% of the
patients at least in Europe and the US (fewer in Israel) decide not to use artificial
respiration and feeding with the paralysis of the respiratory system. This vast
majority of the patients therefore die of unknown respiratory complications under
unknown circumstances. Countries allowing assisted suicide or euthanasia such as
the Netherlands, Belgium, Oregon, Australia and others report even larger death
rates before artificial respiration than countries more restrictive on assisted death
practices such as Germany and Israel. Controlled studies on large populations of
ALS patients have shown [19] that quality of life even in the advanced stages of
ALS is comparable to healthy subjects and emotional status is even better (see [24]).
Despite these data, no reduction in death rates and no increase in artificial respiration
in end-stage ALS are detectable. The great majority of those patients who decide for
life and go under artificial respiration have no brain–computer interface available.