27 September 2023

Seat of knowledge: How a ‘smart toilet’ can screen you for disease

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Hanae Armitage* says a disease-detecting ‘precision health’ toilet can sense multiple signs of illness through automated analysis.

The “smart toilet” isn’t the kind that lifts its own lid in preparation for use; this toilet includes technology that can detect a range of disease markers in stool and urine, including those of some cancers, such as colorectal or urologic cancers.

The device could hold particular appeal for people genetically predisposed to certain conditions, such as irritable bowel syndrome, prostate cancer, or kidney failure, and who want to keep on top of their health.

“Our concept dates back well over 15 years,” says senior author Sanjiv “Sam” Gambhir, Professor and Chair of Radiology at Stanford University.

“When I’d bring it up, people would sort of laugh because it seemed like an interesting idea, but also a bit odd.”

With a pilot study now completed, Gambhir and his team have made their vision of a precision health-focused smart toilet a reality.

Gambhir’s toilet is an ordinary toilet outfitted with gadgets inside the bowl.

These tools use motion sensing to deploy a mixture of tests that assess the health of any deposits.

Urine samples undergo physical and molecular analysis; stool assessment is based on physical characteristics.

The toilet automatically sends data extracted from any sample to a secure, cloud-based system for safekeeping.

In the future, Gambhir says, researchers could integrate the system into any healthcare provider’s record-keeping system for quick and easy access.

The toilet falls into a category of technology known as continuous health monitoring, which encompasses wearables like smart watches.

“The thing about a smart toilet, though, is that unlike wearables, you can’t take it off,” Gambhir says.

“Everyone uses the bathroom — there’s really no avoiding it — and that enhances its value as a disease-detecting device.”

Gambhir, a professor for clinical investigation in cancer research, says although the idea may take some getting used to, he envisions the smart toilet as part of the average home bathroom.

In facilitating that broad adaption, Gambhir designed the “smart” aspect as an add-on — a piece of technology that’s readily integrated into any old porcelain bowl.

“It’s sort of like buying a bidet add-on that can be mounted right into your existing toilet,” he says.

“And like a bidet, it has little extensions that carry out different purposes.”

These extensions sport an array of health-monitoring technologies that look for signs of disease.

Video captures both urine and stool samples and then a set of algorithms processes them.

The algorithms can distinguish normal “urodynamics” (flow rate, stream time, and total volume, among other parameters) and stool consistencies from unhealthy ones.

Alongside physical stream analysis, the toilet also deploys uranalysis strips, or “dipstick tests”, to measure certain molecular features that can point to a spectrum of diseases, from infection to bladder cancer to kidney failure.

In its current stage of development, Gambhir says, the toilet can measure 10 different biomarkers.

It’s still early days, though.

To get a better feel for “user acceptance” more broadly, the team surveyed 300 prospective smart-toilet users.

About 37 per cent say they were “somewhat comfortable” with the idea, and 15 per cent says they were “very comfortable” with the idea of baring it all in the name of precision health.

Built-in ID system

One of the most important aspects of the smart toilet may well be one of the most surprising — and perhaps unnerving: It has a built-in identification system.

“The whole point is to provide precise, individualised health feedback, so we needed to make sure the toilet could discern between users,” Gambhir says.

“To do so, we made a flush lever that reads fingerprints.”

The team realised, however, that fingerprints aren’t quite foolproof.

What if one person uses the toilet, but someone else flushes it?

Or what if the toilet is of the auto-flush variety?

They added a small scanner that images a rather camera-shy part of the body.

You might call it the polar opposite of facial recognition.

In other words, to fully reap the benefits of the smart toilet, users must make their peace with a camera that scans their anus.

“We know it seems weird, but as it turns out, your anal print is unique,” Gambhir says.

The scans are used purely as a recognition system to match users to their specific data.

No one, not you or your doctor, will see the scans.

By no means is this toilet a replacement for a doctor, or even a diagnosis, Gambhir says.

In fact, in many cases, the toilet won’t ever report data to the individual user.

In an ideal scenario, should something questionable arise, an app fitted with privacy protection would send an alert to the user’s healthcare team, allowing professionals to determine the next steps for a proper diagnosis.

A secure, cloud-based system would store the data.

Data protection, in terms of identification and sample analyses, is a crucial piece of this research, Gambhir says.

Next steps

As Gambhir and his team continue to develop the smart toilet, they’re focusing on a few things: increasing the number of participants, integrating molecular features into stool analysis, and refining the technologies that are already working.

They’re even individualising the tests deployed by the toilet.

For example, someone with diabetes may need his or her urine monitored for glucose, whereas someone else who is predisposed to bladder or kidney cancer might want the toilet to monitor for blood.

Gambhir’s other goal is to further develop molecular analysis for stool samples.

“That’s a bit trickier, but we’re working toward it,” Gambhir says.

“The smart toilet is the perfect way to harness a source of data that’s typically ignored — and the user doesn’t have to do anything differently.”

The paper appears in Nature Biomedical Engineering.

* Hanae Armitage is a science writer in the Office of Communications at Stanford University.

This article first appeared at www.futurity.org.

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