Rate of Perceived Stability

The Rate of Perceived Stability (RPS) grew out of our work with video gaming for proactive balance training.  

Two of the many advantages to video gaming include the wide array of challenges afforded in multiple domains, and the ease with which the environments and tasks can be modified and manipulated, particularly in the realm of balance training.  However, there is little research about how to challenge the client's balance most appropriately.  And most especially, there are no methods to quantify the therapeutic aspects of the balance tasks.  

In order to compare proactive and reactive balance training to study their effectiveness and dose response parameters, we needed to be able to measure the intensity of the balance task for each subject.  Clinically and in research, the exercise dosage (frequency, intensity, time, and type) must be quantified in order to set the initial parameters and in order to adjust the dosage appropriately over time.  

Across exercise types, initial load (e.g., intensity, difficulty, excursion) and decisions to modify the load are determined by measurements of the person’s ability to manage the load (e.g., lift a weight a certain number of times, run at a given speed/given heart rate, move through a certain range of motion).  Measures of exercise intensity are used to prescribe dosages and to modulate exercise programs appropriately for best effect and safety; yet, there is not an adequate measure of balance training intensity to quantify, scale and progress balance tasks, clinically or in a research setting.  

Both the Rate of Perceived Exertion (RPE) and the (similar) Borg scale have been shown to be valid in quantifying exercise intensity in several domains.  Similarly, versions of the VAS or 10 point pain scale are very widely used to quantify the very individual domain of the experience of pain. These are self-rating scales; one rates one’s own perception of the exertion or pain rather than the construct  being rated by someone else.  

We maintain that a similar scale could be used for clients to self-rate the level of difficulty of balance tasks as they perform them, allowing clinicians to quantify the training dosage and to assess client responses to training, facilitating safer and more effective  modulation of the balance program.

The Rate of Perceived Stability (RPS) was developed and tested iteratively and then validated during balance training with video games and various balance surfaces. Given that gaming and balance tasks also tax the cardio-respiratory system, we demonstrated that it assesses a different domain than exertion. It has been used successfully in reactive, induced-slip tasks as well.