By Luca Pollonini
In this edition of the newsletter we report on the trending development of portable and wearable fNIRS instruments by featuring the work of Kassab et al. recently published as a technical report in Human Brain Mapping, 39: 7–23 (2017).
The multimodal fNIRS-EEG system integrates 128 optical channels (from pairing 32 dual-wavelength LEDs and 32 APD detectors) and 32 EEG channels in headgear connected to a battery powered, belt-wearable FPGA controller module weighting 650g.
Such a high number of fNIRS channel allows coverage of the majority of the cerebral cortex for a whole-brain study, or can be arranged more densely in specific regions of interest. A rechargeable 10Ah battery guarantees continuous data collection for up to 24hrs, and is connected to a remote computer via wire or Bluetooth for further processing and real-time display.
The proposed system was tested against a commercial EEG system (simultaneous data collection) and an fNIRS system (in different experimental sessions). It performed comparably to both devices during motionless and visual motion experiments. Interestingly, the multimodal system was also tested in the clinic by monitoring single-subject cases of transient ischemic attack (TIA), bilateral temporal lobe epilepsy, refractory status epilepticus, and pre-surgical language lateralization, capturing significant hemodynamic and electrophysiological events across these experiments.
Of importance to the fNIRS community, the authors provide a comprehensive list of relevant literature and instruments featuring wearable fNIRS technologies. Together with groundbreaking efforts from other research groups, this work provides important evidence that wearable fNIRS neuroimaging systems have the potential for clinically-relevant bedside monitoring.
We look forward to further advancements in this exciting field!