Kernel Flow is a non-invasive brain-computer interface (BCI) technology developed by Kernel, a neurotechnology company founded in 2016. Flow uses functional near-infrared spectroscopy (fNIRS) to measure neural activity in the cerebral cortex[1]. This represents a significant advancement in non-invasive brain sensing technology, offering capabilities that bridge the gap between research-grade fMRI and portable EEG systems.
Kernel Flow represents a significant advancement in non-invasive brain sensing technology. Unlike electroencephalography (EEG), which measures electrical signals on the scalp, Flow uses infrared light to detect hemodynamic responses in the brain—similar to functional MRI but with a portable headset form factor[2]. This technology was pioneered by Franz Jobsis in 1977, who first demonstrated the feasibility of non-invasive infrared monitoring of cerebral oxygen sufficiency[3].
The technology measures changes in oxygenated and deoxygenated hemoglobin concentrations in the cortical tissue, which serve as proxies for neural activity through the neurovascular coupling mechanism[4]. This hemodynamic response provides information about brain function that complements the faster electrical signals measured by EEG.
Kernel Flow employs diffuse optical tomography (DOT), an advanced form of fNIRS, to measure[5]:
The system uses arrays of infrared light sources and detectors arranged across the scalp to create a 3D tomographic reconstruction of brain activity. This approach provides better spatial resolution than traditional fNIRS by using multiple overlapping measurement paths[6].
The underlying physics involves the differential absorption of near-infrared light by hemoglobin:
| Feature | Specification | Clinical Significance |
|---|---|---|
| Channels | 48+ optical channels | Dense cortical coverage |
| Sampling Rate | Up to 100 Hz | Real-time monitoring |
| Spatial Resolution | ~1-2 cm (depth-dependent) | Cortical layer specificity |
| Wearability | Full-head headset | Extended monitoring sessions |
| Battery | Wireless, rechargeable | Mobile use |
| Connectivity | Bluetooth 5.0 | Wireless data transfer |
| Wavelengths | Multiple (NIR) | Multi-depth measurement |
| Aspect | Kernel Flow | EEG |
|---|---|---|
| Signal Type | Hemodynamic | Electrical |
| Spatial Resolution | 1-2 cm | 5-10 cm |
| Depth Sensitivity | Cortical only | Surface |
| Robustness | Motion-sensitive | More robust |
| Cognitive Load | Minimal | Minimal |
| Aspect | Kernel Flow | fMRI |
|---|---|---|
| Portability | High (headset) | Very low (scanner) |
| Cost | Low ($10K-30K) | High ($1M+) |
| Noise | Quiet | Loud |
| Motion Constraint | Minimal | Significant |
| Accessibility | Point-of-care | Centralized |
Kernel Flow is primarily marketed for cognitive neuroscience research and applications[7]:
Flow has emerging applications in neurodegenerative disease research[8]:
Kernel Flow has been used in various research studies:
| Study Type | Applications | Key Findings |
|---|---|---|
| Working Memory | Training studies, capacity assessment | Improved understanding of WM mechanisms |
| Attention | ADHD research, vigilance tasks | Attention network connectivity |
| BCI Development | Motor imagery, task paradigms | Feasibility of fNIRS-BCI[13] |
| Rehabilitation | Stroke recovery, neurofeedback | Functional improvement tracking |
While primarily a research tool, fNIRS is being integrated into clinical trials:
| Technology | Spatial Res. | Temporal Res. | Portability | Cost |
|---|---|---|---|---|
| Kernel Flow (fNIRS) | 1-2 cm | Seconds | High | $ |
| EEG | 5-10 cm | Milliseconds | High | $ |
| fMRI | 1-3 mm | Seconds | Very Low | $$$$ |
| MEG | 1-3 cm | Milliseconds | Very Low | $$$$ |
| PET | 4-5 mm | Minutes | Very Low | $$$$ |
Kernel is one of several companies developing non-invasive brain sensing technologies:
| Company | Product | Technology | Primary Use |
|---|---|---|---|
| Kernel | Flow | fNIRS/DOT | Research, cognitive assessment |
| OpenBCI | Ultracortex | EEG | Research, BCI development |
| g.tec | g.Nautilus | EEG | Research, clinical |
| Emotiv | EPOC | EEG | Consumer, research |
| Wearable Sensing | DSI | EEG | Research |
Kernel Flow is primarily sold as a research tool and has not received FDA clearance for clinical diagnostic use. It is available for:
Future clinical applications may pursue:
Kernel Flow applications in Alzheimer's disease[10:1][9:1]:
PD-specific applications:
Stroke rehabilitation applications:
Kernel Flow's fNIRS technology interfaces with several key neurodegenerative disease mechanisms:
Functional near-infrared spectroscopy. Neuroimage. 2012. ↩︎
Noninvasive infrared monitoring of cerebral and myocardial oxygen sufficiency. Science. 1977. ↩︎
Diffuse optical imaging of brain activation. Neuroimage. 2004. ↩︎
fNIRS in cognitive neuroscience. Neuroimage. 2018. ↩︎
fNIRS applications in neuroscience. Front Psychol. 2017. ↩︎
Near-infrared spectroscopy in neurodegenerative disease. J Cereb Blood Flow Metab. 2019. ↩︎
Prefrontal cortex oxygenation in neurodegeneration. Neuroimage Clin. 2015. ↩︎ ↩︎
fNIRS in Alzheimer's disease. J Alzheimers Dis. 2014. ↩︎ ↩︎
Motor learning in Parkinson's disease. Neuroimage. 2013. ↩︎
Near-infrared spectroscopy for stroke rehabilitation. Neurol Med Chir. 2013. ↩︎
fNIRS in brain-computer interface research. Sensors. 2019. ↩︎
fNIRS signal quality assessment. Sensors. 2019. ↩︎