Motion capture suits that bring characters to life in films like Avatar are helping researchers track the onset of diseases which impair movement.
In many cases, the quicker such conditions are assessed the sooner a patient is able to receive the appropriate support and treatment.
The new system uses artificial intelligence to analyse body movements.
In tests, the UK experts measured the severity of two genetic disorders twice as quickly as the best doctors.
The researchers say it could also halve the time and greatly reduce the cost required to develop new drugs in clinical trials.
The research has been published in the journal Nature Medicine.
Dr Valeria Ricotti, of Great Ormond Street Institute for Child Health told BBC News that she was "completely blown away by the results".
"The impact on diagnosis and developing new drugs for a wide range of diseases could be absolutely massive."
Dr Ricotti was among a group of researchers at Imperial College and University College London who spent 10 years developing the new technology.
They tested it on patients with Friedreich's ataxia (FA) and Duchenne Muscular Dystrophy (DMD) in two separate studies. The researchers say it could also be used to monitor patients recovering from other diseases that affect movement.
These include any condition involving the brain and nervous system, heart, lungs, muscles, bone and a number of psychiatric disorders.