Date of Award

Spring 2023

Document Type



Santa Clara : Santa Clara University, 2023.


Bioengineering; Electrical and Computer Engineering

First Advisor

Julia Scott

Second Advisor

Sally Wood

Third Advisor

Emri Araci


Light stimulation or transcranial photobiomodulation (tPBM) therapy has been shown to be effective when treating patients suffering neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. While there is currently no cure, light stimulation can help alleviate symptoms for those patient’s suffering from these diseases. With this in mind, the senior design team from last year began a prototype hybrid electroencephalography (EEG) and tPBM device. They implemented a specific wavelength of 810 nanometer (nm) near-infrared (NIR) light emitting diodes (LEDs), with a 16 channel EEG headset from OpenBCI. The device was intended to serve as a potential research tool, with a closed loop system between the EEG and light stimulation system; this means, changing the light stimulation therapy based on the patient’s EEG measurements.

The goal of this year’s senior design team was to expand and improve the hybrid EEG and tPBM head-device. Last year’s senior design team was able to implement the EEG and LEDs in the same system, however, they were unable to finish closing the loop between the two subsystems. Also, last year’s group was only able to work with 810 nm LEDs, but this year we were lucky enough to receive 1070 nm LEDs from the Quiet Mind Foundation. These LEDs are shown to be more effective in stimulation than that of the 810 nm; this is due to the fact that the 1070 nm wavelength is better absorbed by tissue than the 810 nm, and can penetrate deeper from a further range. There is also evidence that light sensitive ion channels in neurons are tuned to 1070 nm and not 810. However, 1070 nm LEDs are considerably more expensive than the 810 nm, as well as difficult to access. These trade-offs were important to consider when designing our device, as we wanted to reach specific benefits and functional criteria. We worked together as an interdisciplinary team, both bioengineers and electrical, in order to progress towards a fully closed loop system, enhance the user interface, and implement these newly received diodes.