# Open-Motion stroke detector by Openwater

Canonical page: https://technooptimist.io/neurotech/open-motion
Frontier: [Neurotech](https://technooptimist.io/neurotech.md) · Field: Non-invasive brain reading · Company: [Openwater](https://technooptimist.io/companies/openwater.md)
Stage: Pilot (3 of 5: Research → Proto → Pilot → Deploy → Scaling)
Updated: last update 2025-05-08, facts checked 2026-10-11
Goal: Let ambulance crews spot large-vessel strokes on the spot and drive them straight to one of the minority of hospitals that can remove the clot, since every hour of delay costs brain tissue.
Status: Research use only; peer-reviewed studies at US stroke centres, FDA filing still ahead
Next milestone: Validate in ambulances and file with FDA

## Milestones

| Status | Milestone | Date | Slip |
| --- | --- | --- | --- |
| Done | Two-centre study: 79% sensitivity, 84% specificity (preprint) | 15 Dec 2023 |   |
| Done | Paper on tunable thresholds for pre-hospital use | 8 May 2025 |   |
| Done | Portable modular devices begin shipping | 2025 |   |
| Current | Validate in ambulances and file with FDA |   |   |

## Most important updates

- **8 May 2025**: Studies show Openwater's portable blood flow monitor detects large-vessel strokes better than standard field scales. A Journal of Stroke and Cerebrovascular Diseases paper showed Open-Motion can be tuned toward catching more large-clot strokes or toward fewer false alarms, to fit transport distances and hospital capabilities. ([our story](https://technooptimist.io/stories/studies-show-openwater-s-portable-blood-flow-monitor-detects-large-770ab667.md) · [original source](https://www.einpresswire.com/article/810706727/researchers-using-openwater-monitor-report-accurate-detection-of-large-vessel-occlusion-in-suspected-stroke))

## Current obstacles

- **From hospital to ambulance**: Results so far come from emergency departments; the authors say the method must be validated on a fresh test set in the pre-hospital setting.
- **Missed clots versus false alarms**: At 79% sensitivity one in five large clots is missed; tuning for sensitivity raises false transfers, a trade-off each region must set.

## Physics limits

- **Light barely gets through the skull**: Scalp and bone scatter and absorb most light, so only a tiny fraction returns from the brain's surface layers; deep vessels are inferred, not seen.
- **Flow is an indirect clue**: The device sees blood flow changes, not the clot itself, so other conditions that alter flow can mimic or mask a blockage.

## How it works

### Illuminate: Infrared light into the head

Near-infrared light passes through scalp and skull; light scattered by moving red blood cells forms a flickering speckle pattern.

### Measure: Speckle contrast becomes a flow waveform

Faster blood flow blurs the speckle more; tracking speckle contrast gives a waveform of brain blood flow with every heartbeat.

### Classify: AI reads the waveform

A transformer deep-learning model trained on patient scans flags the flow pattern typical of a large blocked artery.

## Spec sheet

| Spec | Open-Motion stroke detector | Provenance |
| --- | --- | --- |
| Scan time | 60 s at the bedside | reported |
| Sensitivity for big clots | 79% (vs 60% for RACE scale) | reported |
| Specificity | 84% | reported |
| Accuracy (AUC) | 0.82 (RACE 0.70, LAMS 0.65) | reported |
| Study size | 135 patients, 2 stroke centres | reported |
| Regulatory status | Research use only, not FDA evaluated | reported |

Provenance: reported = stated by the company; estimated = our estimate; sample = a sample figure.

## Papers and demos

- **15 Dec 2023** (paper): [Portable cerebral blood flow monitor to detect large vessel occlusion in suspected stroke patients (preprint)](https://www.medrxiv.org/node/740704). 79% sensitivity, 84% specificity in 135 patients, beating standard stroke scales.

## About Openwater

Openwater is a San Francisco company founded in 2016 by Mary Lou Jepsen that builds low-cost, open-source devices using light and ultrasound: Open-Motion reads blood flow in the brain to spot strokes, Open-LIFU stimulates brain circuits.

- Open-sources its designs: software under the Affero GPL, hardware under a Creative Commons licence.
- Raised $100M in total by August 2024 from investors including Khosla Ventures and Peter Gabriel.
- Neither device is FDA cleared yet; the stroke detector is furthest along. Aims for units under $1,000.

- Founded: 2016
- Headquarters: US
- Status: private
- People: Mary Lou Jepsen (Founder and chair); Aaron Timm (CEO)
- Partners, customers, investors: Khosla Ventures (investor); Plum Alley Ventures (investor); University of Pennsylvania (partner); University of Arizona (partner); NC State University and UNC-Chapel Hill (partner)

Company page: https://technooptimist.io/companies/openwater.md

## Related programs

More from Openwater:

- [Open-LIFU](https://technooptimist.io/neurotech/open-lifu.md) (Pilot)

Everything in Neurotech: https://technooptimist.io/neurotech.md

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