The document discusses a SomaSensor device that uses near infrared spectroscopy (NIRS) to non-invasively measure oxygen saturation levels in the brain. It works by emitting light through the skull from an LED light source and detecting the light at different depths using photodetectors on the surface of the head, allowing it to isolate changes in the brain by subtracting the shallow measurement from the deep one. This technique provides depth resolution to minimize contamination from superficial signals.

43. UP REGULATION

92. Deep
Photodetector
Skin
Skull
Light
Emitting
Diode
Cerebral
Cortex
Surface
Photodetector
SomaSensor
Depth Resolution with
Near Infrared Spectroscopy (NIRS)
Adult SomaSensor®
Illustration of incandescent light
through human skull
The INVOS System is based on Somanetics’ proprietary
INVOS® (In Vivo Optical Spectroscopy) technology.
By placing two detectors at different distances from the
light source, two depths of penetration can be
measured. Subtracting the shallow measurement from
the deep minimizes superficial signal contamination,
and isolates changes in oxygen saturation in the brain.
This is called “depth resolution.”