The PortaMon is our wireless portable NIRS system, designed specifically for measurements of muscle tissue. The system measures the tissue saturation of the investigated muscle. We call this ’tissue saturation index’ (TSI). In addition to TSI, the system also measures oxygenation changes in terms of oxy-hemoglobin, deoxy-hemoglobin, and total hemoglobin, which is an indication of the blood volume in the muscle.
Typical applications of the PortaMon are found in sports science, training evaluation, rehabilitation medicine, high-altitude research, compartment syndrome, occupational health and peripheral vascular disease.
- Measures oxy, de-oxy, and total hemoglobin and tissue saturation
- Bluetooth connection (up to 150 meters)
- On-line or on-board data collection
- State-of-the-art exchangeable and rechargeable battery for 8 to 10 hours operation time
- The size of a cell phone (83 by 52 by 20 mm)
- Weighs only 88 grams, including battery
- Superior analysis software, Oxysoft
- Optional built-in accelerometer
- Note: The PortaMon is sold for research purposes only.
OxySoft NIRS acquisition and analysis software (5)
This is really dependent on the signal quality. Typically for normal cortical penetration you will want anywhere from 3cm up, the larger the distance the deeper the penetration however at the sake of a reduced signal-to-noise ratio. Typically for normal adults we employ a 3.5cm interoptode distance, for those with darker skin or dark/dense hair you may need to reduce this to achieve an ideal SNR. For younger children and infants often times 2.5cm is more common.
fNIRS is of course a completely different modality than fMRI, however while the mechanics may differ there is overlap in the resulting measurements, ultimately cerebral blood flow and metabolic measurements may be obtained, and neuronal activation often assumed. fNIRS is specific to oxygenated and deoxygenated hemoglobin measurement and quantification due to light back reflection, while fMRI aligns the orientation of the hemoglobin depending on the presence of oxygen. fNIRS offers a much better temporal resolution often 100x or more, while spatially fMRI has the upper hand by roughly 10x.
Very good, and important, question. Clearly fNIRS is employing frequencies of light that are purposely used to traverse the skull without much restraint, and this is in fact introducing exogenous stimuli. Well don’t fret, the amount of signal power using fNIRS can be comparable to sunlight. Further, of recent, several studies suggest there are various health benefits to infrared light stimulation at the cellular/metabolic level- even still these studies primarily employ chronic use.
This is a tough one, inherently hair is the nemesis of any fNIRS device on the market and while we all would like to say we have this completely figured out it ultimately comes down to proper preparation, part of which is also a skill in performing. I would use the same criteria with regard screening as you may normally do with EEG.
OxySoft is developed for use with Windows 7 or 10, both are supported however Windows 7 is still preferred. We also offer a free Android application for the PortaLite and PortaMon units for streaming and data logging.