Neurofeedback without EEG?

How the brain “works” and sometimes doesn't work - how it is affected by ageing, trauma, disease and other factors - has been studied from many different viewpoints.  Brain function is always in the news it seems today. It might be news related to the growing awareness of head injuries in sports, or concerns of an ageing population and fears of dementia. It's an ancient puzzle that we are still getting to grips with.

For much of the history of research into brain function, a neurochemical paradigm has been the most actively researched; driven by the commercial potential of finding appropriate medication. 

The neuroelectrical behaviour of the brain has not received anything like as much attention although we have known for many years that electrical signals certainly flow through the brain and body.  We have been able to detect and study the EEG signals emitted from the brain for many years but this is not the complete story either. 

Up until now neurofeedback has largely been synonymous with EEG as the source signal

The EEG is not there for any physiological reason and it doesn't really reflect the brain's "business" in any direct sense. It's an indirect and yet useful pointer to the underlying brain's network activity that we have learned to take advantage of.  An expert working with EEG can gain a great deal of insight into what is happening in the brain in the same way that a mechanic can listen to the hum of a machine and understand a great deal of what is happening inside. This of course is not the same as fixing the problem.  Neurofeedback employing EEG has allowed us to take steps in this direction.

Ideally we need to act on the fact that communication patterns in the brain are basically a blend of both chemical and electrical signals and methodologies that blend both viewpoints are needed.

Neurofeedback in action

Neurofeedback is a well known field now that sprang up with the aim of providing a method to alleviate a disorder or change some particular brain rhythm for beneficial effect.  Neurofeedback now has many and varied clinical and research applications.  It is also widely used in Sport applications. It has relied upon measuring and feeding back to the subject the essence of EEG signals detected from the scalp. 

Neurofeedback works when the brain is presented wth information (by this feedback process) that is related to it's own function in a way that it (the brain) can use to facilitate beneficial change. The mechanism depends on the brain differentiating or learning to distinguish one state from another - a beneficial state from an undesirable one.

Up until now neurofeedback has largely been synonymous with EEG as the source signal and for that reason neurofeedback is sometimes referred to as EEG biofeedback.  

Neurofeedback has tended to rely on EEG signals and classification approaches

Emerging fields of study suggest that we might have to rethink the automatic association of neurofeedback with EEG.

Real time functional magnetic resonance imaging (rtfMRI) neurofeedback

Many of us are aware of so called Functional MRI (fMRI) which provides a non-invasive window on brain function. It can employ blood oxygenation level dependent (BOLD) contrast, which means that the MRI signal goes up and down in accordance with brain-activity related changes in blood perfusion.  We are able to get a direct measure of the region by region activation level in the brain.

The best-known application is task-fMRI. In this case, the subject performs a task within the scanner while his or her brain is being scanned every 2-3 seconds. By processing such a dataset, so called activation maps can be derived by contrasting the scans under different conditions, e.g. active task versus rest, or task A versus task B.

A recently developed fMRI modality is real-time fMRI neurofeedback (rtfMRI-NF), in which a subject's brain activity is assessed already during scanning.  A certain measure of ongoing brain activity is then provided as feedback.  RtfMRI was developed initially in 1995 and the potential for this approach as a potential neurotherapeutic tool for brain disorder treatment was demonstrated in 2005.

Just as in EEG biofeedback, the subject is thus made aware of and may act upon, his/her own brain activity patterns in a “closed loop” control setup. 

In depression, for example, rtfMRI-NF has been used to train patients to influence positively a pathologically decreased amygdala activity, with the result that they become less depressed.

The recent publication by Stoeckel et al (see below) is well worth a read as it highlights proposed studies of rtfMRI neurofeedback for clinical therapeutics. The article aims to encourage future research that will contribute to evidence based guidelines and clinical trials.

NEU3CA program

Within the NEU3CA brain research program (Neurodegeneration, Neuronal networks and Neuromodulation in accelerated Cognitive Ageing in epilepsy), technicians and clinicians from TU/e, (Eindhoven), Ghent University Hospital, and Maastricht UMC are investigating the cognitive side effects of epilepsy, and how to mitigate them.  It has been estimated that 65% of epilepsy patients have cognitive complaints, and these account for 45% of the disease burden. Clinical care, however, is still mainly focused on seizure management. The Neu3ca research program aims to increase awareness of, insight into and treatment options, for cognitive impairments in epilepsy.

These developments support the evolution and the application of neurofeedback as an approach and are likely to provide new insights to the ancient puzzle of how the brain works and what to do when it doesnt.

Reference

Stoeckel; L.E. et al
Review Article
Optimizing real time fMRI neurofeedback for therapeutic discovery and development
NeuroImage: Clinical, Volume 5, 2014, Pages 245–255
http://dx.doi.org/10.1016/j.nicl.2014.07.002