Temple can track changes in brain blood flow: Deepinder Goyal shares validation study

Deepinder Goyal says Temple can track changes in brain blood flow. He also shared its first validation study, which compares Temple's Brain Flow reading with an established TCD test.Temple is designed to non-invasively track cerebral blood flow and other neurological signals.Deepinder Goyal’s Temple is getting a lot of buzz for its unusual design and the kind of health data it aims to track. Unlike usual health-tracking wearables, Temple is not worn on the wrist or finger. Instead, the tiny device sits on the side of the forehead, around the temple. According to the company the device can track signals linked to the brain and body, giving users a closer look at how their body responds to things such as exercise, rest and other activities. Now, Goyal says Temple will also track changes in brain blood flow and has shared the first study testing this feature. In his latest post on X, Goyal revealed that Temple can track changes in brain blood flow and shared what he described as the device’s first validation study. The study tests Temple’s Brain Flow index against Transcranial Doppler (TCD), an established ultrasound technique used to measure blood-flow velocity in the brain.Temple's first validation study is out.Researchers tested Temple's Brain Flow index head-to-head against Transcranial Doppler (TCD), the gold standard for measuring cerebrovascular function. 23 healthy adults, two challenges: cycling and a standing-to-supine postural shift. pic.twitter.com/LKFT5MWp4W— Deepinder Goyal (@deepigoyal) September 7, 2026Titled “Concordance Between a Temple-Worn Optical Wearable and Transcranial Doppler During Exercise and Postural Transitions in Healthy Adults,” the study looks at whether Temple’s Brain Flow reading changes in the same way as brain blood-flow measurements from TCD.The researchers tested Temple on 23 healthy adults to see whether its Brain Flow reading could pick up changes in brain blood flow. Data from 20 people was used for each of the two tests. During the research, participants were first asked to cycle and then rest. As expected, their brain blood-flow velocity increased while they were exercising and came down during recovery. According to researchers, Temple’s Brain Flow reading followed the same pattern, suggesting that the wearable was picking up the change in blood flow.The researchers then tested the device in a different way by asking participants to move between standing and lying down. After this activity the brain blood-flow velocity of the participants increased, while their heart rate actually decreased. Temple’s Brain Flow reading reportedly increased too. Looking at both tests, the researchers found that Temple’s Brain Flow reading closely followed the TCD measurements. In simpler terms, the study found that when brain blood flow changed, Temple picked up a similar change in its reading compared with the medical device used for comparison.How does Temple track brain blood flow?According to the company, Temple uses a small optical sensor on the side of the forehead. It uses light to pick up signals from the area, which are then used to calculate the Brain Flow reading.But there is an important point here. Temple does not directly measure the amount of blood flowing through the brain. Instead, it records changes in optical signals from the temple area and uses them to generate a Brain Flow reading. The researchers then compared these readings with changes recorded by the TCD device. The study found that both followed a similar pattern.The researchers, however, note that there is still more to prove. The study was small and involved young, healthy adults, and the paper is currently a preprint that has not been peer reviewed. The researchers say larger studies and more testing will be needed to understand how closely the Brain Flow reading reflects changes in brain blood flow.When is Temple launching?Meanwhile, the study comes as Temple gets closer to its wider launch. Goyal recently revealed that the latest version of the wearable is now less than half the size of the earlier model. He has also said limited-edition pre-orders will open soon, with shipments expected before the end of 2026. There is still no confirmed launch date or final price.- EndsPublished By: Divya BhatiPublished On: Sep 7, 2026 18:53 IST