Melanin Bias in Cerebral fNIRS: A Monte Carlo Study Toward Equitable Optical Brain Sensing

Functional near-infrared spectroscopy (fNIRS) is an optical biosensing modality that transduces cortical hemodynamics into a measurable near-infrared signal, underpinning wearable brain monitors and brain–computer interfaces (BCIs). Because epidermal melanin is a strong near-infrared absorber, device sensitivity may depend on skin tone, raising an equity concern for optical neural biosensors. (1)

Objective

We quantify, by Monte Carlo simulation, how epidermal melanin biases the cerebral sensitivity of continuous-wave fNIRS biosensors across the Fitzpatrick scale, and evaluate source-wavelength selection as a device-level mitigation. (2)