# Non-invasive Intracranial Pressure Sensing with Near Infrared Light for Monitoring the Healthy and Diseased Brain

> **NIH NIH R21** · CARNEGIE-MELLON UNIVERSITY · 2020 · $183,773

## Abstract

Project Summary: This project aims to establish near-infrared spectroscopy (NIRS), which is a non-invasive
optical technique sensitive to cerebral hemodynamic changes, as a tool to monitor intracranial pressure (ICP)
non-invasively. The healthy brain maintains a relatively constant blood flow even during episodes of stress and
changes in cerebral perfusion pressure (CPP), which is defined as the difference between mean arterial pressure
(MAP) and intracranial pressure (ICP). The mechanism preserving blood flow is called cerebral autoregulation
(CA), which is known to be impaired in a variety of diseases. Cerebral autoregulation can be evaluated by means
of pressure reactivity, by correlating changes in MAP to ICP. In the healthy brain, changes in MAP are
counterbalanced by changes in ICP and autoregulation is thought to be intact. When autoregulation is impaired,
such as in traumatic brain injured patients, MAP changes are directly translated to and correlated with ICP
changes. Using this metric of correlation to guide CPP management in traumatic brain injury patient has shown
to improve patient outcome, while managing MAP alone, without considering correlation to ICP, does not, thus
demonstrating the importance of ICP measurements. However, this requires ICP to be measured by placing an
invasive pressure sensor in the brain. While CPP management is hypothesized to benefit patients with impaired
autoregulation, placing an ICP sensor is not always an option and recommended in a variety of diseases,
including stroke, sepsis, and Parkinson’s. In addition, neuronal activity plays a role in cerebral autoregulation
due to neuro-vascular coupling, but is generally not taken into account for CPP management. Neurovascular
coupling is known to be disrupted in hypertension, Alzheimer disease, and ischemic stroke, which may be due
to impaired autoregulation. However, the relationship between neurovascular coupling, CPP, and autoregulation
has not been explored in detail. Therefore, this proposals is aiming at establishing NIRS as a non-invasive
alternative to monitoring ICP for guiding clinical management of CPP. For this we will first perform experiments
on non-human primates, where controlled changes in ICP and MAP will be induced while measuring
hemodynamic changes with NIRS. Using a transfer function approach, we will establish the mathematical tools
to translate changes in hemoglobin concentration into ICP traces. Furthermore, we will use electrode arrays
(‘Utah’ array) combined with NIRS sensors during resting state and a functional activation, again in non-human
primates. These experiments will allow us to quantify neuro-vascular coupling by means of the hemodynamic
response function as a function of ICP and CPP. Combined, the results from these experiments will allow us to
establish NIRS for ICP monitoring and will pave the way for management of CPP in patients where ICP
measurements are not possible, ultimately not only providing tools for advanced ...

## Key facts

- **NIH application ID:** 9827573
- **Project number:** 5R21EB024675-03
- **Recipient organization:** CARNEGIE-MELLON UNIVERSITY
- **Principal Investigator:** Jana Maria Kainerstorfer
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $183,773
- **Award type:** 5
- **Project period:** 2017-12-01 → 2021-11-30

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9827573

## Citation

> US National Institutes of Health, RePORTER application 9827573, Non-invasive Intracranial Pressure Sensing with Near Infrared Light for Monitoring the Healthy and Diseased Brain (5R21EB024675-03). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9827573. Licensed CC0.

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