Walk this way

‘Digital insoles’ with embedded motion and pressure sensors are a promising new tool to better diagnose and monitor disorders of the bones, muscles, and joints.

Image credit: Public domain (CC0)

The way we walk – our ‘gait’ – is a key indicator of health. Gait irregularities like limping, shuffling or a slow pace can be signs of muscle or joint problems. Assessing a patient’s gait is therefore an important element in diagnosing these conditions, and in evaluating whether treatments are working.

Gait is often assessed via a simple visual inspection, with patients being asked to walk back and forth in a doctor’s office. While quick and easy, this approach is highly subjective and therefore imprecise. ‘Objective gait analysis’ is a more accurate alternative, but it relies on tests being conducted in specialised laboratories with large-scale, expensive equipment operated by highly trained staff. Unfortunately, this means that gait laboratories are not accessible for everyday clinical use.

In response, Wipperman et al. aimed to develop a low-cost alternative to the complex equipment used in gait laboratories. To do this, they harnessed wearable sensor technologies – devices that can directly measure physiological data while embedded in clothing or attached to the user. Wearable sensors have the advantage of being cheap, easy to use, and able to provide clinically useful information without specially trained staff.

Wipperman et al. analysed data from classic gait laboratory devices, as well as ‘digital insoles’ equipped with sensors that captured foot movements and pressure as participants walked. The analysis first ‘trained’ on data from gait laboratories (called force plates) and then applied the method to gait measurements obtained from digital insoles worn by either healthy participants or patients with knee problems.

Analysis of the pressure data from the insoles confirmed that they could accurately predict which measurements were from healthy individuals, and which were from patients. The gait characteristics detected by the insoles were also comparable to lab-based measurements – in other words, the insoles provided similar type and quality of data as a gait laboratory. Further analysis revealed that information from just a single step could reveal additional information about the subject’s walking.

These results support the use of wearable devices as a simple and relatively inexpensive way to measure gait in everyday clinical practice, without the need for specialised laboratories and visits to the doctor’s office. Although the digital insoles will require further analytical and clinical study before they can be widely used, Wipperman et al. hope they will eventually make monitoring muscle and joint conditions easier and more affordable.