Core Concepts
CogniDot is a miniature, low-cost, and energy-efficient skin sensor that can accurately differentiate between three levels of cognitive load by monitoring vascular activity through a single-pixel color sensor.
Abstract
The paper introduces CogniDot, a compact (22mm diameter, 8.5mm thickness) and low-power skin sensor designed for continuous monitoring of cognitive load. CogniDot leverages vascular activity, including changes in blood flow, blood perfusion rate, and blood oxygen levels, as an indicator of cognitive load.
The key highlights are:
Hardware Design: CogniDot has a sandwich structure with a five-channel color sensor (TCS3430) and three light sources (white LED, 730nm IR LED, 940nm IR LED) to capture both visible and near-infrared (NIR) reflections from the skin and underlying vessels. The bio-compatible adhesive gel allows easy and robust attachment to the temporal area of the head.
Signal Processing: CogniDot uses the NIR channel data to calculate changes in oxygenated (HbO2) and deoxygenated (Hb) hemoglobin concentrations. It also leverages the visible light channel to calibrate the NIR data and remove static drift.
Evaluation: A user study with 12 participants performing cognitive tasks of varying difficulty levels showed that CogniDot can accurately differentiate between three levels of cognitive load with a within-user accuracy of 97%.
Applications and Design Implications: CogniDot's miniature size, low power, and Bluetooth connectivity make it suitable for seamless integration into various wearable devices to enable real-time cognitive load monitoring and adaptation in smart systems.
Stats
When cognitive load increases, HbO2 will increase and Hb will decrease relatively.
When a person returns to a normal resting state, HbO2 will decrease and Hb will increase accordingly.
Quotes
"Vascular activities offer valuable signatures for psychological monitoring applications."
"CogniDot can accurately differentiate between three levels of cognitive loads with a within-user accuracy of 97%."