Charity Insights

My final week at the Royal Hospital for Neuro-disability (RHN) has revealed that inevitably I’m not the only person examining the possibilities for improved seating design. From car seats to desk chairs to wheelchairs, the message is always the same; using new technologies future seats can and need to be better designed around the human body. There’s an asterisk on the end of that phrase though: the sheer amount of variation doesn’t make this an easy task. To this end a great deal of time this week has been spent reading through academic papers examining different aspects or users of all sorts of chairs, and obtaining the many papers referenced in each. The result is that I have more papers to go through than I started with earlier this week, and I run the risk of adding to an exponentially increasing stockpile!

To summarise my findings so far; the prevailing opinion is that spreading the person’s weight as evenly as possible over the seat contact area is the best way to prevent long-term seating injury for the reasons discussed in my Week 2 post. On the other hand a few papers suggest that reducing the pressure over certain weaker parts of the rear and maximising the pressure around the area underneath the strong pelvis bone is the best way forward. Depending on which theory was supported, various researchers have developed methods and devices to shape the seat to best fit the patient. One example used an array of sliding upright rods fitted with pressure and location sensors on which the patient sat to create a set of points in 3D space that represent the contours of the chair. A linked computer would then examine the measured pressure at each rod location and slide the rods up or down while the patient was still seated to achieve a better pressure distribution. The adjusted 3D point set would then be used by automated tools to manufacture the seat. The biggest problem with many of these solutions is the cost and practicability of implementing them alongside recommendations by trained therapists, who are conventionally responsible for gauging a disabled patient’s mobility and seating needs.

This project was always intended to be a first step in investigating possible solutions to future wheelchair designs for severely disabled patients. After conducting research towards this aim, focussing in particular on improving the seat design, I can confirm that there is a great deal more juice in this project yet. The hospital has therefore agreed that I continue this project, with the aim of submitting a report on the progress of the project and possible design solutions at the end of the summer. Some prototyping along the way is a strong possibility!

I have definitely enjoyed the last 4 weeks, meeting new people at the hospital and engaging in fascinating discussions with them. These have opened not only my eyes to the reality of caring for disabled patients, but have also caused the staff to ask themselves new questions and challenge the conventional ways of designing wheelchairs and wheelchair seats. As well as reading a great deal into the research topics, I have through trial and error experimented with new ways to organise and structure my research that will no doubt help in the years to come.

Best of luck to all those also completing their Charity Insights placements this summer. If you’re reading this while considering completing a Charity Insights placement in the future, believe me it’s well worth it!

Read Fourth and final week at the Royal Hospital for Neuro-disability in full

Scientists from all walks of life will likely be familiar with the concept of known unknowns and unknown unknowns. I believe these two phrases can be considered synonyms for research. I started this week with a set of known unknowns; research avenues to pursue given where I thought I could gain information to aid the development of the wheelchair seat prescription device I mentioned in my last post. By the end of this week, after travelling through link after link online and receiving a ton of leads from discussions with hospital staff, this project has gained more facets than it started with. It turns out there are far more unknown unknowns than known unknowns in this project!

It started with a simple question: ‘This hospital has developed a system for creating wheelchair seats. Surely other institutions have developed their own systems?’ Yes they have. In fact, research around the problem of pressure sores in wheelchair-bound patients I mentioned in my last post has been going on since at least the early 1970s. Even more interestingly, the processes still in use by the Royal Hospital for Neuro-disability (RHN) were first outlined over 30 years ago in several of these research papers. While carving the seat from a foam block remains a widely used technique, more radical solutions have been offered in the last few decades. One example builds the seat from a matrix of linked ball-and-socket joints that are infinitely configurable and can be easily adjusted as the patient’s condition and posture develops. Another example creates the seat by pouring a liquid into a bag on which the patient is then seated, that dries and expands into a foam. These newer solutions all have their benefits and flaws. While being infinitely configurable, the ball-and-socket joints in the first example can loosen with time, disrupting the initial shape that perfectly suited the patient. While the second example possibly creates a more accurate mould, it is a labour-intensive process which can easily go wrong.

The question of how to create the seat quickly and efficiently is only half the problem. As was the topic of my last post, a seat for a typical RHN patient serves two main purposes; to maintain their posture and distribute their body weight correctly over the seat to prevent pressure sores. The solutions mentioned above all aim to address these requirements. However my discussions with hospital staff have revealed that the way wheelchairs are typically used in rehabilitation hospitals presents a fresh set of design considerations which the designers may never have foreseen – the unknown unknowns if you will. This includes how the seats will respond to slings being left between the patient and the seat, and the effect of adult nappies on the pressure distribution. At the same time, my forays into research papers on the topic of pressure distribution have suggested that there is more to the topic than meets the eye, and certainly more than the aforementioned seat solutions seem to account for. I can’t say I’ve yet come to any strong conclusions on the matter myself!

My research into these considerations using predominantly academic papers will continue into the fourth week in order to create as well-rounded a design solution as possible, whether it be for a permanent seat or a seat prescription device.

Read Week 3 at the Royal Hospital for Neuro-disability in full

It is often the case with many a soap opera episode that the opening story leads on to a bigger issue that takes up the remaining time of the episode before reaching resolution at the end.

My Charity Insights project, much like many a research project, is beginning to resemble such an episode. The problems with current wheelchairs as identified at the outset have swiftly revealed a deeply related and possibly more fundamental issue with wheelchairs. The seat, the undeniably most important wheelchair component, is fundamentally flawed.

It’s a problem rehabilitation hospitals and companies alike have been trying to solve for decades. How do you design a seat that is applicable to the widest spectrum of users? Current wheelchair seats range from the very basic foldable fabric sling seat used predominantly by people unable to walk but able to use their upper body and arms, to the carer-propelled custom-moulded foam seat used almost everywhere at the Royal Hospital for Neuro-disability (RHN). Between those options there is a plethora of seat designs incorporating space age hydrophobic covers and countless repositionable cushion pads. Each has their pros and cons. The question is what factors are you trying to maximise and minimise for a particular patient?

In the case of the patients cared for by the RHN, there are two important functions the seat must serve. The first is that the seat must maintain the patient’s correct posture as in most cases they do not have the ability to maintain that correct posture on their own. The second function is inseparable from the first and attempts to solve a problem able-bodied people will likely never have.

Consider a wooden park bench and a padded armchair. Which would you rather spend 3 hours sitting on non-stop? I would hope you would find the armchair more comfortable, and the reason is fairly obvious. It’s not simply that the armchair is softer. Instead, it deforms to spread your weight more evenly over your rear and back, while a flat hard bench doesn’t deform at all and creates pressure points over the bony areas of your rear. The result is that you will find yourself shifting around on the bench more often than on the armchair to move the maximum pressure point away from the part that is aching.

Now consider this. A wheelchair patient at the RHN remains seated for around 3 hours between rests, when they are hoisted out of their wheelchair and onto a bed perhaps. A flat hard wheelchair seat will be more than just unconformable after a while. Alongside excess moisture and friction, prolonged high pressure over a particular part of the body results in the development of a pressure sore over that area, which can take months to heal. For patients who are unable to shift themselves in their seat, the current solution is to spread the weight as evenly over their body as possible by moulding a seat that is unique to that patient’s body. Even this design has limitations as it is only effective when the patient remains perfectly still all the time. There will always be some movement, even if it is as simple as the patient sliding downwards a little. The majority of high-end wheelchairs feature a tilting mechanism that allow the entire seat to pivot, relieving the posterior from carrying the entirety of the patient’s weight, and instead placing some of it on the back.

My main aim this week was to find out more about this seat problem, the current solutions and possible solutions for the future. This has involved a close examination of the current seat moulding method used at the hospital, and an investigation into alternative techniques. The aim is to develop a universally applicable device that can be used to prescribe a more effective seat design that better distributes the patient’s weight and is more versatile to changes in the patient’s body as their condition develops.

I have a lot of research paper digging to do!

Read Week 2 at the Royal Hospital for Neuro-disability in full

If you’re reading this as a fellow engineer, I have a challenge for you. Strike up a debate with a doctor about which of your two professions is best, and I guarantee you that the doctor will rebut with the indisputable repost: ‘the human body is the ultimate engineering’. Try and counter that one!

This is exactly the realm I entered upon starting my first day at the Royal Hospital for Neuro-disability for my Charity Insights placement this summer. I received several slightly surprised looks as I introduced myself not as a medical student eager to delve into the world of neuroscience, but as a student of mechanical engineering with no inclination to becoming a doctor. A valid question arises; what am I doing in a hospital?

As the name implies, this is not your typical multi-purpose hospital. It was established over 160 years ago as a service ‘to give permanent relief to such persons as are hopelessly disqualified for the duties of life, by disease, accident or deformity’. Today its beautiful 18th century buildings remain and it cares for hundreds of patients suffering from a variety of severe neurological diseases. Its most important motive is ‘Finding Ability in Disability’, and that’s where I come in.

My task during the placement is to examine the current design and prescription of wheelchairs for hospital patients, and investigate new designs and processes that more effectively meet the patients’ needs.

My first day began with a tour of the hospital and its facilities by the Principal Medical Officer and the Associate Director of the Institute. They demonstrated how several currently used wheelchairs work and pointed out what they had gathered about their design flaws. Due to the unique requirements of many of the patients, some of the components of the standard wheelchairs had been replaced with parts custom designed and built at the hospital. Even these bespoke components needed improving in several ways. I was introduced to the biomedical engineering staff at the hospital and shown around the on-site workshop they use to manufacture parts.

Much of the remainder of the week involved getting up to speed with the latest developments in wheelchair design and outlining the improvements that can be made to existing designs as well as exploring fresh ideas. I look forward to seeing what path the research takes!

Read Week 1 at the Royal Hospital for Neuro-disability in full