Presented By

Viacheslav Danilov, PhD

ML/AI Engineer and Research Scientist

Working at the intersection of AI, optical sensing, and translational health technology

AI SystemsOptical SensingClinical ML

SafeICP

A Safe Window IntoBrain Pressure

Non-invasive intracranial pressure estimation through optical sensing and machine learning.

OpticalExternalNon-invasive

Why ICP Matters

The pressure mattersThe measurement still hurts

Intracranial pressure is a critical brain-health signal, but the gold standard still relies on invasive monitoring through a surgically placed sensor.

Surgical Access

Measurement requires drilling into the skull.

Infection Risk

Every inserted sensor carries bleeding and contamination risk.

Limited Eligibility

Procedural risk decides who gets monitored and for how long.

Reduced Monitoring

Vulnerable patients and lower-acuity settings lose continuous insight.

Clinical Contrast

The gold standard goes inThe safer vision stays outside

Gold Standard

Invasive intracranial sensor placement

Direct ICP sensing is clinically trusted, but surgical access makes the workflow resource-heavy, infection-prone, and unsuitable for continuous or broad monitoring.

SafeICP Direction

External optical sensing at the bedside

SafeICP reframes the measurement problem: keep the signal outside the skull, at the bedside, and recover ICP-relevant information through optical sensing plus machine learning.

What SafeICP Is

SafeICP is not only a deviceIt is a measurement pipeline

SafeICP combines bedside optical sensing, signal interpretation, and machine learning-based ICP estimation into one non-invasive monitoring approach.

SCOS Sensing PrincipleDiagram of fiber-coupled SCOS setup: NIR laser, optical fiber, forehead probe, tissue interaction zone, and CMOS sensor

Sense

Bedside optical capture

NIR light and a forehead probe acquire blood-flow signal

Read

Dynamic signal patterns

Speckle dynamics reveal cerebral hemodynamic behavior

Infer

ICP-relevant output

ML maps temporal patterns to pressure estimates

Hardware Translation

From lab rig to bedside deviceThe form factor changed

Legacy platform

Rack-based DCS research system

Large footprint, exposed instrumentation, and cable-heavy integration make the setup scientifically capable but operationally hard to translate.

SafeICP direction

Compact SCOS bedside-oriented device

Smaller, more integrated hardware moves the same sensing ambition toward a form factor that feels more credible for bedside and longitudinal use.

Probe ContextScientific illustration showing external optical sensing and invasive ICP reference context
A probe-context figure showing the key sensing logic: optical measurement from outside the skull, with ICP referenced from the inside.

Device Logic

Light goes inUseful dynamics come back

SafeICP uses safe near-infrared illumination and a forehead probe to read out blood-flow-related behavior without placing the sensing hardware inside the skull.

Placement

Forehead probe

The optical interface sits outside the head, at the bedside.

Illumination

Near-infrared light

Light travels through tissue and interacts with moving blood cells.

Readout

Speckle and flow dynamics

Fluctuation patterns become a non-invasive signal linked to cerebral blood flow.

From Optical Signal To ICP

The device does not read pressure directlyIt learns the mapping

SafeICP measures optical dynamics tied to blood flow, not ICP itself. To produce a pressure estimate, the system needs a learned time-series translation from signal behavior to pressure behavior.

Measured

Optical time series

Flow-related fluctuations, speckle behavior, and temporal signal structure.

Predicted

Intracranial pressure estimate

Clinically meaningful pressure output aligned to paired invasive reference data.

Dataset

The models learn from paired optical and invasive dataTwo cohorts, 68 subjects

The learning problem is only credible because the optical recordings are paired with invasive ICP measurements. The dataset is centered on iNPH and expanded with Katzman infusion data to expose the models to broader pressure variation.

iNPH cohort

58 subjects

Idiopathic normal pressure hydrocephalus — a condition where cerebrospinal fluid accumulates in the brain, causing gait, cognitive, and urinary symptoms.

Katzman cohort

10 subjects

Katzman infusion tests with controlled CSF pressure elevation, expanding the ICP range beyond baseline hydrocephalus levels.

What each training sample needs

Optical signal windowpaired withInvasive ICP reference

Data Preparation

Two-level stratified splittingNo data leakage between subjects

Subjects are first split at the patient level using K-means stratification on BFI and ICP statistics, then each training subject is internally split into 5 folds for cross-validation. Both hemispheres from the same patient always stay in the same set.

1

Subject-Level Split

Stratified K-means clustering

3 clusters are formed from per-subject statistics (mean, std, median, Q1, Q3, IQR of BFI and ICP). Subjects are then allocated 80/20 to train+val and test, preserving cohort distribution.

54 train+val subjects14 test subjects3 clusters
2

Within-Subject Split

5-fold random cross-validation

Each measurement in the train+val set is independently split into 5 folds with 80% training and 20% validation per fold. This produces 5 separate train/val assignments per recording.

5 folds80/20 train/val ratioseed 11 reproducible
3

Windowing

Sliding windows for model input

600 samples/window~15 s per windowstride 10 overlap

Cross-Validation

Each fold sees different validation windowsSame subject, different splits

For each of the 5 folds, a different 20% of the recording is held out for validation. The animation below cycles through all folds for Subject 17.

Pink regionsValidation windows for the current fold. The remaining signal is used for training.
Dashed linesFragment boundaries within the recording session, preserved across all folds.

Model Benchmark

10 time series architecturesTrained under identical conditions

We evaluate models spanning four architectural families: RNN hybrids, convolutional networks, transformers, and kernel-based methods. All are implemented via the TSAI library and trained with identical hyperparameters for a fair comparison.

Training configuration

Optimizer: AdamLoss: MAELR: 0.0001Batch: 128Dropout: 0.25Epochs: 5
FamilyModelYearParams, kMACs, M
RNNLSTM-FCN2017785319
RNNGRU-FCN2018655319
CNNmWDN20184,239554
CNNTCN201867188
CNNResCNN2019256309
CNNInceptionTime2019389471
CNNXceptionTime2019399294
CNNXCM2021616740
Transf.TST20217031,653
KernelMultiRocket2022149<1

Parameters = total learnable weights (thousands). MACs = multiply-accumulate operations per forward pass (millions).

Qualitative Evidence

The prediction tracks the shape,not just the average

A representative InceptionTime example shows that the model follows the overall temporal behavior of invasive ICP well enough to make the learned relationship visually credible.

Subject 08InceptionTimeMAE 2.8 mmHg
Prediction versus true ICP for subject 08 using the InceptionTime model
What to noticeThe solid blue line is the mean prediction averaged across five cross-validation folds. The shaded blue band is the 95% confidence interval across those folds. Together they follow the broad temporal structure of the green invasive ICP reference.
Where it remains hardSharp transitions and sudden ICP spikes are still more difficult to capture than slower baseline trends. The confidence interval widens noticeably around these rapid changes, reflecting higher model disagreement at the hardest moments.

Quantitative Evidence

Competitive errorCautious confidence

SafeICP reaches competitive MAE, but its uncertainty remains under-calibrated.

Best overall MAE

5.3 mmHg

mWDN on the right hemisphere

Low-error zone

52%

Predictions within 0–4 mmHg

PICP coverage

37%

Too low for trustworthy confidence

ModelMAE LeftMAE RightRead

InceptionTime

6.0

5.4

Competitive

mWDN

6.3

5.3

Strongest overall

TCN

7.1

5.6

Useful baseline
mWDN error distribution histogram and cumulative accuracy curve from the SafeICP report

Read of the chart

Dense low-error region52% within 0–4 mmHgCoverage still lags

Interpretation

The pipeline is credibleThe hard clinical edge case is not solved yet

The method is credible, but the hardest clinical regime is still unresolved.

Balanced read

Strong proof of principle, not yet a finished clinical monitor.

5-6 mmHg MAE120+ synchronized patients

Demonstrated

Competitive ICP estimation around 5-6 mmHg MAE.

Tracks temporal ICP behavior, not just static levels.

Still Limited

Too few high-ICP cases for robust edge-case behavior.

Uncertainty remains under-calibrated and too optimistic.

Why It Matters

Makes non-invasive ICP monitoring technically credible.

Creates a stronger base for broader clinical validation.

Impact And Next Steps

SafeICP makes non-invasive ICP monitoringa realistic clinical path

The foundation is in place; the next gains come from data, calibration, and translation.

Already established

Paired optical and invasive datasets

Working bedside-oriented prototypes

Active hospital and clinical partners

Next-step roadmap

01

Broaden
data

Expand high-ICP and multi-hospital cohorts.

02

Calibrate confidence

Improve uncertainty and elevated-range reliability.

03

Refine workflow

Improve use-case fit and anatomical correction logic.

04

Translate clinically

Prepare for trials, validation, and bedside adoption.

Conclusion

Accuracy is now a matter ofclinical refinement, not feasibility

SafeICP already produces error levels that are close enough to clinical benchmarks to focus the next phase on generalization, cohort breadth, and stability on unseen data.

Where the work shifts now

The sensing stack is credible. The remaining gap is reducing the validation-to-test spread and proving robustness across broader patient conditions.

Reference standard

WHO invasive ICP thresholds

WHO logo for medical standards
0–20 mmHg±2 mmHg
>20 mmHg±10%

Observed performance

Model error on held data

Neural network icon for machine learning error
Validation2.6 mmHg
Test5.3 mmHg

Interpretation

The result is strongest on validation and still competitive on test, which makes the next milestone less about inventing a new approach and more about tightening generalization.

The Consortium

Four partners coveringthe whole translation chain

Each partner covers a part of the pipeline the others cannot.

Already operational

The collaboration is already operating across data, devices, and bedside validation.

Photonics & Device

SCOS hardware and optical sensing

Machine Learning

Time-series models and uncertainty analysis

Clinical Translation

Recruitment, validation, and bedside workflow

Industrial Validation

Safety engineering and product validation

The Team

The people behind SafeICP

Researchers, clinicians, and engineers from four institutions, each contributing to the domain

Institute of Photonic Sciences

Turgut Durduran

Turgut
Durduran

Principal Investigator

Mirko Fornasier

Mirko
Fornasier

Doctoral Researcher

Carolina Vega

Carolina
Vega

Doctoral Researcher

Monica Torrecilla

Monica
Torrecilla

Doctoral Researcher

Pompeu Fabra University

Viacheslav Danilov

Viacheslav
Danilov

Research Scientist

Gemma Piella

Gemma
Piella

Professor

Anton Makoveev

Anton
Makoveev

Research Scientist

Vall d'Hebron Hospital

Maria A. Poca

Maria
Poca

Head of Neurosurgery

Juan Sahuquillo

Juan
Sahuquillo

Neurosurgeon

Murad Al-Nusaif

Murad
Al-Nusaif

Doctoral Researcher

ProCareLight

Youcef Lebour

Youcef
Lebour

Research Engineer

SafeICP

Questions & Answers

Is it possible to directly measure ICP non-invasively?

Not reliably. A direct ICP sensor must communicate with the intracranial CSF/brain compartment, so non-invasive signals can only estimate or trend ICP.

How can ICP be estimated without measuring pressure directly?

The device captures optical dynamics tied to cerebral blood flow, then learns a mapping from synchronized optical windows to invasive ICP references.

Which model is strongest in the current comparison?

mWDN is the strongest overall in the reported results, reaching 5.3 mmHg MAE on the right hemisphere and the highest concentration of low-error predictions.

What makes the current result clinically credible already?

The models are trained and evaluated against invasive ICP, not a proxy label, and they reach competitive error in the 5-6 mmHg range while tracking temporal ICP behavior.

What is the main limitation today?

The hardest problem is elevated ICP and trustworthy uncertainty. Coverage stays well below the nominal target, so confidence estimates are still too optimistic.

Why compare several model families instead of picking one architecture first?

Because this is a time-series translation problem. InceptionTime, mWDN, and TCN test different temporal biases and reveal which one fits the paired signal-to-ICP mapping best.