Researchers around the world are racing to turn pain--medicine's most subjective vital sign--into something a camera or sensor can score as reliably as blood pressure. The push has already produced PainChek--a smartphone app that scans people's faces for tiny muscle movements and uses artificial intelligence to output a pain score--which has been cleared by regulators on three continents and has logged more than 10 million pain assessments. Other startups are beginning to make similar inroads. The way we assess pain may finally be shifting, but when algorithms measure our suffering, does that change the way we treat it? This story is from the latest print issue of MIT Technology Review magazine, which is full of fascinating stories about our bodies. Someone I know became a conspiracy theorist seemingly overnight.

But can technology describe something so personal? But this week I've also been wondering how science and technology can help answer that question--especially when it comes to pain. In the latest issue of magazine, Deena Mousa describes how an AI-powered smartphone app is being used to assess how much pain a person is in . The app, and other tools like it, could help doctors and caregivers. They could be especially useful in the care of people who aren't able to tell others how they are feeling. But they are far from perfect.

London (CNN Business)When you're in pain, you can usually tell someone about it. But for people with communication difficulties, that isn't always an option, meaning pain often goes undetected, misinterpreted or wrongly treated. To give a voice to those who can't report their suffering, such as people with dementia, PainChek, an Australian startup, has developed an app that uses facial analysis and artificial intelligence (AI) to assess and score pain levels. A carer records a short video of the subject's face using a smartphone and answers questions about their behavior, movements and speech. The app's AI recognizes facial muscle movements that are associated with pain and combines this with the carer's observations to calculate an overall pain score.