Functional Optical Brain Imaging Sensor utilizing Near Infrared

TechnologyAta Akin, Banu Onaral, Kambiz Pourrezaei

Drexel UniversityScott Bunce

MCP Hahnemann UniversityBritton Chance, Shoko NiokaUniversity of Pennsylvania

Sponsors: ONR

Drexel University

Project Overview

•Objectives• Research, development and deployment

of an optical brain monitoring/imaging system based on functional Near Infrared (fNIR) imaging modality.

• Deployment in various health applications where blood oxygenation of the prefrontal cortex is linked to the state of mental engagement and other educational and clinical parameters.

Project Goals

• An integration of a pulse laser/LEDs, low power circuitry, and signal and image processing:• To provide a means to assess the performance of

a pilot or operator,• To measure cognitive over-load,• Compatible with existing legacy and COTS

systems

• Dual use deployment, military and civilian (healthcare, training and education)

Biophotonics Optical techniques for diagnostic and therapeutic

applications

Diagnostics & Imaging Treatment & Surgery

Microscopic< 100m

Macroscopic > 100m

•Two-Photon (multi photon) microscopy•Fluorescence microscopy•Optical Coherence Tomography•Tissue spectroscopy

•X-Ray•Optical Radiation (thermograph)•Diffuse Photon Density Waves

•Photodynamic therapy•Laser surgery

Fields of Application

Dermatology, plastic surgeryCardiovascular interventionsGastrointestinal surgeryBreast cancer diagnosisOphthalmic technologiesDentistryBrain Activity MonitoringMuscular ActivationMetabolism ResearchOthers

Laser tissue interactionTissue engineeringThermal treatment of tissueFunctional imaging of living cells and tissuesMicroscopyMolecular probes and dyesNanoparticlesTumor treatmentMicroarraysOthers

Clinical Applications Basic Sciences

FOCUS OF TODAY’S PRESENTATION

Optical Window in Tissue

Near IR

Light in the 700-900 nm wavelength range (Near Infrared) can penetrate into tissue up to 5-6 cmLight sources working within this range can be used in investigating the optical properties of tissue

800 nm Source: Detects changes in Blood Volume

850 nm Source: Detects changes in oxygenated-Hb ([HbO2])

750 nm Source: Detects changes in deoxygenated-Hb ([Hb])

Physics of Light Tissue interaction

Single Scattering

Multiple Scattering

Diffusion Process

In air

In Clean Water

In Tissue

Activation Areas

Imaging Cognition II: An empirical Review of 275 PET and fMRI StudiesR. Cabeza and L. NybergJ. Cognitive Neuroscience, (12):1, pp. 1-47, 2000

Process Areas

Attention 9

Working Memory (object) 9, 46, 45,44

Semantic Memory Retrieval (Categorization)

45

Episodic Memory Encoding (Object)

6, 9, 46, 45,44

Episodic Memory Retrieval (nonverbal)

10, 9, 44

Probing Brain with Light

K K

Na

ATPase

Neuron

Glia

K

K

Metabolic Factors

K : di lation

H : di lation

adenosine : dilation

Spatial Buffering

ECF

[1]  W. Kuschinsky, “Neuronal-vascular coupling, a unifying hypothesis,” in Optical Imaging of Brain Function and Metabolism II, ed. A. Villringer and U. Dirnagl, Plenum Press, 1997

P. J. Magistretti and L.Pellerin, “Metabolic coupling during activation,” in Optical Imaging of Brain Function and Metabolism II, ed. A. Villringer and U. Dirnagl, Plenum Press, 1997

Photon Migration in TissueSource

Detector

Work in Progress

• Noninvasive•Non-intrusive •Safe• Affordable• Portable• Combines spatial resolution and time resolution

COGNISCOPE:BRAIN ACTIVITY MONITOR

Cogniscope• Combination of EEG and fNIR sensors to continuously monitor

neuronal and hemodynamic changes

• Motivation: A need to monitor brain activity with high temporal resolution (10 ms range) to better quantify physiological changes due to external stimuli

• Hypothesis:

• A portable optical brain imaging system can provide a quantitative and fast means of monitoring and imaging cognitive brain activity under mental stress

• The relationship between neuronal (EEG) and hemodynamic activity (fNIR) can be established to evaluate/predict human performance under stress

Cogniscope

• Potential Uses• Cognitive activity engagement

• Classroom evaluation

• Soldier/pilot state monitoring

• Alertness/vigilance assessment

• Mental disorders assessment

• Sleep disorders

• Co-registration with fMRI

• Others…

Headpiece

Receiver

Host Server

Patent Pending

f N I R O p t o d e s E E G E le c t r o d e

F le x C i r c u i t s

B a t t e r i e s

Cogniscope Headband

System on Chip•DAQ•T/R•Power

DSP•Data Fusion•Diagnostics•Alarm

Patent Pending

Long-term Goals

• Develop a quantitative technique to evaluate human performance based on the fusion of several physiological parameters

• Use of multi-modality signal/image acquisition/processing in modeling dynamic interactions between cognition, perception, memory, learning, emotional control mechanisms and decision under stress