Answer on the tip of your tongue

The eyes are the windows to the soul, says the adage. In traditional Chinese medicine, though, it's the tongue that gives insight into the overall physical status of the body, otherwise known as zheng.

Now, in a modern update to the ancient practice, University of Missouri researchers, working in collaboration with Beijing's Tsinghua University, have developed computer software that does tongue analysis to warn of disease.

Based on this software, the researchers aim to create an application for smartphones within the next year that will allow anyone to take a photo of their tongue and learn the status of their zheng. This could help both practitioners and patients better predict or prevent disorders and chronic conditions.

'Zheng is an overall description of health, similar to how Westerners look at body temperature and blood pressure to gauge physical status. Zheng is of a similar spirit,' says Professor Xu Dong, chairman of Missouri's computer science department in the college of engineering and study co-author.

'In a healthy state, your zheng is balanced, and if you exhibit abnormal features, such as a discoloured tongue, your zheng is unbalanced.

'Knowing your zheng classification can serve as a pre-screening tool and help with preventive medicine. Our software helps bridge Eastern and Western medicine, since an imbalance in zheng could serve as a warning to go see a doctor.'

Chinese medicine practitioners believe the colour and texture of the tongue is a mirror of internal organ health. The software analyses images based on the tongue's colour and coating to distinguish between tongues showing signs of 'hot' or 'cold' zheng.

Shades of red and yellow are associated with hot zheng, whereas a white coating on the tongue is a sign of cold zheng. Hot and cold zheng don't refer directly to body temperature; they point to a combination of symptoms associated with the state of the body as a whole, says Xu.

A person with cold zheng, for example, may feel chills and coolness in the limbs and have a pale face. Their voice may be high-pitched. Other symptoms of cold zheng are clear urine and loose stool. They may also prefer hot food and drinks, and desire warm environments.

Both hot and cold zheng can be symptoms of gastritis, an inflammation of the stomach lining often caused by bacterial infection.

In the study, published in the journal Evidence Based Complementary and Alternative Medicine in May, the researchers analysed the tongues of 268 gastritis patients and 48 healthy patients using their new software.

The gastritis patients were classified by whether they showed infection by a certain bacteria, known as Helicobacter pylori, as well as the intensity of their gastritis symptoms. In addition, most of the gastritis patients had been previously classified with either hot or cold zheng. This allowed the researchers to verify the accuracy of the software's analysis.

'The study results had the software classifying patients with an accuracy rate of about 80 per cent, which is an excellent performance,' says Xu. The software was able to discern healthy from unhealthy patients as well as discriminate between hot and cold zheng.

Xu and his team believe the tool could be a useful predictor of one's physical status and as a pre-screening tool for many conditions. 'Unlike today, the image will provide a permanent and objective record for the doctor and the patient to access and evaluate,' says Xu.

The first market launch for the application will be in the US within a year. 'Initially the software application will be used for entertainment with a disclaimer stating the predictive nature of the software is for consumer knowledge and fun only,' Xu says.

The smartphone app will be a pilot with the goal of a launch for the professional Chinese medicine market once the software is fine-tuned to 100 per cent accuracy.

'We want to build a three-dimensional image of the tongue that can evaluate the texture or coating, colour and shape,' Xu says. 'So far we have collected hundreds of tongue images.'

The research team believe their software will not only determine overall health related to digestive disorders, but also indicate risks for diabetes, heart disease and other chronic conditions. In this way, the application could be an early step in standardising tongue analysis, which may also help to advance TCM theory scientifically.