Scientific Background

Scientific Background The Applied Neurophysiology Lab

 

I. Providing practical markers of attention
We can talk on an attention spectrum, including alertness, orientation and sustained attention
Attention could be viewed as a global increase in activation of brain modules. This global increase promotes general activity in these brain modules, and then activations of specific perceptions and actions may be evoked, in the various brain modules, on the basis of the specific stimuli to which we are exposed, and the associations that our brain has learned. Without this global increase in activation, that we may term attention, the relevant perceptions and actions, in various brain modules, may not reach the activation threshold.

This multi-brain-module increase in activation, which we term attention, is embodied by several distinct brain mechanisms. For applicative purposes we find it useful to follow a long-standing distinction among three embodiments of such attentional processes: (1) alertness, (2) orientation and (3) sustained attention. However, we prefer to tune the definition of these processes, in order to use them practically.
Alertness could be viewed as a non-specific global increase in activity, which is impacted by stimuli, or internally evoked brain representations, which are of major importance to us. For example, painful stimuli, anxiety, or other causes of great excitation, increase our alertness.

Orientation could be viewed as a transient (often sub-second) increase in activity of multiple relevant brain modules, which are involved in the processing of specific stimuli, or internally evoked brain representations, which are of potential importance to us. This transient increase in activity may, or may not, be followed by further attentional allocation and processing.

Sustained attention could be viewed as a lasting (multiple seconds) increase in activity of multiple relevant brain modules, which are involved in the processing of specific stimuli, or internally evoked brain representations, which have been designated as important for further current processing.

Vast literature on electrophysiological markers of the attention spectrum, and on clinical deviations

Thousands of studies, and many reviews, have reported EEG markers for attention in general, and specifically for the sub-processes of alertness, orientation and sustained attention. Attention-related markers are known to deviate from the normal range in multiple disorders. They tend to be very low in stroke, traumatic brain injury, encephalitis, encephalopathy and seizures. They also tend to be low in ADHD, dementia, depression and schizophrenia. They tend to be high in anxiety and pain. 


 

Most markers are cumbersome to extract. We have developed single channel real-time markers

However, the prevailing markers, which are reported in the literature, often involve multiple EEG channels, which takes time to apply, and also long sampling times, in the scale of several minutes for obtaining one marker value. This renders them somewhat cumbersome for routine daily use by most potential users, who were not trained as EEG technicians.

We have developed and validated real-time one-channel markers for the three attentional processes

As the attention-related processes involve multiple brain modules, their electrophysiological manifestations are spread over the cortex and the scalp. When we look at the multi-channel EEG signals, we can see the strong synchronization among channels. If-fact, the synchronization is easily noted, and it is often more challenging to detect consistent differences among the channels. Therefore, as they are spread and synchronized across channels, and emerge from the activity of multiple brain modules, attention-related electrophysiological markers are measurable from single channels, without significant loss of information [https://pubmed.ncbi.nlm.nih.gov/25445244/].

We developed markers, which are measured conveniently in real-time from a single channel at the pre-frontal region, from a wearable headset below the hairline, for the three attention sub-processes – alertness, orientation and sustained attention.

 

Our markers have been validated in studies with thousands of patients from multiple clinical populations. 

Currently, we enable researchers world-wide to use our markers for free, and multiple studies are being published independently by other research groups.

II. Practical indications, which are gained from the markers of the three attentional processes
Deviations in sustained attention markers indicate two types of barriers to cognitive effort
Deviating sustained attention indicates a barrier to the engagement of cognitive effort. We use the cognitive effort index (CEI) to monitor sustained attention. We identify automatically two types of barriers to sustained attention and engagement in cognitive effort: (1) cognitive barriers, and (2) affective barriers. Cognitive barriers are identified, by the CEI monitor, when the values are rather consistently below the low threshold. Affective barriers are identified, by the monitor, when the values of the marker are changed sharply either to below the low threshold (an avoidance pattern), or to above the high threshold (an anxious pattern, in which intense attention is directed to the stressor). When the values of the marker are rather consistently in the middle range, between the low and high thresholds, the sustained attention is considered effective (no barrier).


 

Reduced orientation markers indicate severe brain dysfunction (encephalopathy)
Even when the level of consciousness is reduced, e.g. due to a disorder of consciousness or due to anesthesia, the brain continues to orient to strong external stimuli, but does not tend to continue with their processing thereafter, as the allocation of sustained attention is reduced. In such conditions, the sustained attention marker (CEI) will be low, but the orientation marker will not be significantly reduced [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7026482/]. If the orientation marker is also reduced, it may indicate severe brain dysfunction, or encephalopathy [https://pubmed.ncbi.nlm.nih.gov/37321874/]. We use the brain reactivity index (BRI) to monitor orientation in such conditions of reduced consciousness. 

Deviating alertness markers indicate changes in stress response     
Increased alertness may indicate stress. Reduced alertness may indicate relaxation, and if during a task, which might be subjectively threatening, it may indicate dissociation. We use the tension index (TensI) to monitor alertness.

III. Harnessing the indications gained from the markers to develop useful tools and services
This trio of easy-to-use, real-time, markers of attention-related processes, CEI, BRI and TensI, enables us to develop tools and services for various important uses – both clinical and para-clinical, or non-clinical. We work on a range of projects for developing such tools and services in multiple areas, including: prevention and treatment of asphyxia and perinatal complications in obstetrics; monitoring to avoid and treat complications in the various intensive care units (ICU), starting from the neonatal ICU; monitoring to avoid and treat complications in the operating room during surgery and anesthesia, and in the peri-operative period; assisting the efficacy of treatment and directing treatment for various neurological and psychiatric disorders; rehabilitation of multiple conditions – including physical rehabilitation (physiotherapy), cognitive rehabilitation, speech rehabilitation, rehabilitation of disorders of consciousness, and rehabilitation of patients with chronic pain; there are also non-clinical, or para-clinical fields in which we are active – such as education and problem solving. We find this wide range of projects to be useful, as insights gained in one field could often be applied in other fields.
Our work in the various fields is based on collaborations with leading clinicians and researchers. We are always happy to expand our collaborations for the development of important applications. We also encourage researchers to use our markers independently, for free, according to their own interest. A continuously growing number of studies are led and published independently by other researchers who use our tools.
Below you can find the list of our currently available tools and services. For further inquiries please contact us at [email protected].