Significance: This study is a preliminary step toward the identification of a noninvasive and reliable tool for monitoring the presence and progress of gaiting dysfunctions.
Aim: We present the results of a pilot study for monitoring the motor cortex hemodynamic response function (HRF) in freely walking subjects, with time-domain functional near-infrared spectroscopy (TD fNIRS).
Approach: A compact and wearable single-channel TD fNIRS oximeter was employed. The lower limb motor cortex area of three healthy subjects was monitored while performing two different freely moving gaiting tasks: forward and backward walking.
Results: The time course of oxygenated and deoxygenated hemoglobin was measured during the different walking tasks. Brain motor cortex hemodynamic activations have been analyzed throughout an adaptive HRF fitting procedure, showing a greater involvement of motor area in the backward walking task. By comparison with the HRF obtained in a finger-tapping task performed in a still condition, we excluded any effect of motion artifacts in the gaiting tasks.
Conclusions: For the first time to our knowledge, the hemodynamic motor cortex response was measured by TD fNIRS during natural, freely walking exercises. The cortical response during forward and backward walking shows differences, possibly related to the diverse involvement of the motor cortex in the two types of gaiting.
We present a lightweight TD-NIRS system, two-wavelength, one detection channel that can be battery operated and worn as a backpack for freely-moving cerebral and muscle hemodynamic monitoring. Oxy- and deoxy-genated hemoglobin absolute concentration can be retrieved in real time even in outdoor measurements thanks to the rugged feature of the device.
We present a wearable TD-NIRS system (two wavelengths, one channel). The system is battery operated, can be remotely controlled and is able to perform measurements on brain and muscle on freely-moving subjects.
For the first time, we are proposing a compressive-sensing approach to time-domain diffuse Raman spectroscopy for depth probing of multilayer diffusive media. We built a spectrometer capable of both spectral and temporal acquisition with a single-pixel detector and tested it for depth sectioning on a bilayer tissue-mimicking phantom.