How to Translate Emerging Technology from the Lab to the Clinic

As a product engineer, I develop products that are used in research labs. There are a lot of products currently available on the market, some of them are, in fact, developed in labs. And I understand that it can be very confusing and very overwhelming to choose the right product or technology for your application. 

For the purposes of this blog, I'm going to present the greatest technology available that supports multisensory fusion and we're going to go through different categories. 

Let's start first with the definition of multisensory fusion. Humans use different sensory inputs while maintaining balance and for functional movement. It's like a closed loop feedback control system where you integrate different sources of sensory information. The visual system helps us with direction and action planning, the somatosensory system tells you where your body is in space, and the vestibular system helps us to interpret rotations, translations, and head movements. Now, these three systems combined with auditory, tactile help us to keep balance and to accomplish our daily life activities. And that's why it is termed multisensory fusion. 

Though we are always trying to use all the systems, sometimes we have to change their emphasis to accomplish our tasks. For example, if you're walking on a street and suddenly all the lights turn off. Now you cannot rely on vision, so you use either tactile or even auditory feedback to help you cross the path. This is called reweighting. This also happens due to aging or due to an injury. It is necessary to study the individual contribution of each of these sensory inputs and be able to train them. This is where technology can help us.

Next, let's look at which technology aids in each of these sensory modes. The visual system helps us with direction, action planning, and facilitates movement training. The products displaying visual feedback range from large cave environments like the one pictured below to head mounted displays. 

Cave environments can be used to cause distractions or perturbations to record subject behavior to such visual changes. For certain populations, these perturbations can be provided in head mounted displays. A home-based system like the one pictured above utilizes IMUs to transfer data to the computer wirelessly. It helps subjects receive feedback about their movements so that they can do them as prescribed. Visual feedback design can be simple graphs or they can be complex scene designs. Complex scenes tend to be more engaging, but you have to be careful that they're not too overwhelming for the subject. 

Rhythmic auditory training has been shown to be very effective in facilitating movements such as walking in those with neurological disorders like Parkinson's, and it's also useful for learning a novel movement pattern. Auditory feedback can be in the form of alarms or sonification. Auditory alarms are used in gait studies. For example, using force sensing resistors in insoles and an auditory feedback look in the form of beeps to denote heel strike conveyed through speakers or headphones. Auditory feedback is also used in exoskeletons if some predefined kinematic angle is exceeded.

Another form of feedback is sonification, which is changing the magnitude of parameters of sound such as volume, pitch, stereo balance, timbre over time. This can be used for multidimensional training. 

Somatosensory is the stimulation felt by skin, either due to vibration or pressure. Insoles can improve spatiotemporal parameters of gait by delivering vibratory stimulation using piezo electric actuators. Somatosensory or proprioception also tells us about the position and movement of our body parts. For example, when I'm dancing, when I'm placing my foot, when I'm moving my hands around, I can do all these things without actually looking at where I'm placing my foot or where I'm moving my hand. This proprioception plays a very important role in balance. 

To assess the contribution of proprioception, a subject is asked to stand on the moving base and then the effect of that is recorded on postural sway. By perturbing the base, you are challenging the somatosensory input. 

Another way of categorizing these products is based on the information that the user receives while using them, either the knowledge of results or knowledge of performance. Both of the examples below are telerehabilitation apps that are used by patients after hip replacement surgery. This one on the left is an example of knowledge of results because it gives you information regarding the outcome in form of the number of repetitions, durations, number of lunges, lunge duration, etc. The other example tells you about the arm extension, so it is an example of knowledge of performance. You'll receive details about the movement and technique. 

Products can also be categorized as those giving real-time or terminal feedback. Systems like the one below give real-time feedback to the subject about movement, you can see it is almost mirroring the participant. It guides the subject through the task and is very effective in the early learning phase. Often during a protocol, researchers usually fade out the real-time feedback over time and slowly start replacing it with terminal feedback i.e. giving user information about the movement after the task is completed, either in the form of verbal feedback or in the form of reports or assessments. This reduces the dependency on feedback and allows retention. 

Below you will see products that are used in clinics and labs as well as products used at home such as instrumented crutches. The products used in clinics such as this computerized dynamic posturography system is not feasible for home use due to their price point or size. These devices offer multimodal feedback, modularity in designing your own protocol, so do to the flexibility for a lab, it can actually prove to be cost-effective. 

When choosing the optimum technology for your study keep in mind your subject population, funds available, is the study inside the lab, outside on a field, or at home. Further, when you select a product, what is the optimal dosage? How much feedback is good feedback and not overwhelming for the subject? 

In this blog, we’ve explored various technologies available for studying multisensory feedback and how they help in movement assessment, training, and rehabilitation. Technology has always aided science for implementation, quantification, and justification. As our understanding of science associated with movement paradigms has grown, technology has followed by adding multisensory feedback in form of visuals, sound, haptic. My goal in explaining these products of technology and the way they are classified is to make it easier for you to make decisions when you have to choose what to use for your study.

About the Author

Jaswandi Pitale has a Ph.D. from The Ohio State University in Mechanical Engineering with a focus on auditory feedback, biomechanics, clinical rehabilitation, and product development.