An AI-powered test that listens for signs of stress in people’s voices and claimed to be 'clinical grade' provides inconsistent results when tested on the same person twice, according to researchers.

Cigna's StressWaves Test is a free online tool that uses voice recognition to evaluate and reveal stress levels in 90 seconds by analysing stress through acoustic (sounds, such as tone, pitch, pause, etc.) and semantic (word choices and syntax) patterns. 

Levels range from 'Extremely Stressed' to 'No Stress', along with a portrait that visualises the effect of stress on the user's body and mind.

Cigna marketed StressWaves as 'clinical grade' tool. 

However, according a detailed, independent evaluation by Arizona State University researchers, the tool gives inconsistent results when tested on the same person twice, calling into question its efficacy and marketing claims. 

The researchers also call out Cigna's reluctance to share sufficient validation data, making it difficult to evaluate the model.