Siddharth Krishnan

Siddharth Krishnan, a materials scientist at MIT, developed a tiny sensor that could save people from a devastating and often deadly brain condition. 

Between one and two in every 1,000 babies born in the United States have hydrocephalus, a condition in which cerebrospinal fluid builds up in the brain. It can also occur later in life, including after traumatic brain injury. Over a million people in the United States have hydrocephalus, and nearly all of them have a shunt installed that drains fluid from their brain into their chest or abdomen. The condition can be fatal if untreated, but if it’s dealt with promptly a full recovery is often possible.

If shunts fail, because they get clogged, then fluid will again build up in the brain. This happens to about half of shunts within six years, so it’s a major problem. 

Earlier techniques for detecting shunt failure all had various shortcomings. Repeated CT scans, MRIs, or x-rays subject patients to dangerous doses of radiation, cost a lot, and—because they measure the performance of shunts only indirectly—are not all that reliable. Sometimes, invasive brain surgery is done just to verify that a shunt is working. And because checks were being performed only a few times a year, patients and their families had to live with constant uncertainty, wondering if their shunts were working properly. 

In any case, because the flow of fluid from the brain is naturally intermittent, spot checks don’t necessarily catch problems.

Krishnan’s sensor offers a noninvasive way to monitor the flow in shunts: it can be placed over the skin on the neck, near the valve. It measures the temperature at several distinct spots, inferring from the temperature distribution at those spots whether or not liquid is flowing. Unlike an earlier generation of noninvasive sensors, which made fewer temperature measurements and required the use of an ice pack, his device can continuously measure the flow, reporting results via Bluetooth. 

So far, field trials on seven patients reported in a paper earlier this year in the journal NPJ Digital Medicine show that his sensor gives “robust, high-quality data” for hours at a time.

Krishnan hopes that his sensor will have applications beyond hydrocephalus, possibly monitoring other diseases like diabetes, where tiny changes beneath the skin can have huge effects.