Motorists with peripheral neuropathy had less pedal control, found Professor Dilwyn Marple-Horvat
A study into the impact on driving caused by diabetic nerve damage sheds new light on how motorists with diabetes can better prepare for the road.
Diabetics can suffer a complication called diabetic peripheral neuropathy which results in damage to the nerves, and the symptoms can include numbness and tingling, loss of coordination and muscle weakness, particularly in the feet.
In the first study of its kind, researchers from Manchester Metropolitan University ran a series of simulator tests to examine how driving behaviour is affected by diabetic peripheral neuropathy and the associated loss of sensation and reduced proprioception – the awareness of where your limbs are in relation to each other.
They discovered important differences in how diabetics with nerve damage used the accelerator pedal and found they had less precise control of the pedal compared with both non-diabetics and diabetics without diabetic neuropathy.
The impact of peripheral neuropathy on car pedal control is a less well-known consideration for diabetic motorists than maintaining good eyesight or preventing a hypoglycaemic attack behind the wheel, suggesting the need for increased awareness and training from health practitioners.
However, the research, published in Diabetic Medicine journal, also showed people with diabetic neuropathy can learn to counteract the impact of the condition.
Lead academic Dilwyn Marple-Horvat, Professor of Motor Neuroscience at Manchester Metropolitan, said:
Importantly, we found that people got better from one test drive to the next, which suggests people with diabetic neuropathy improve when driving the same route repeatedly, as in your daily commute.
Perhaps they could improve more if given feedback and instruction, and we have some ideas for technological solutions and training programmes to do this.
We found those with diabetic neuropathy had less subtle control of the accelerator, using its mid-range much less than other drivers — they tended to either only lightly touch the pedal, or really put their foot down, resulting in strong acceleration so that after just a few seconds the car would be moving much more quickly.
We found this sometimes led to a driver needing to make quicker and bigger movements of the steering wheel to stay in lane, which is not ideal.”
Prof Marple-Horvat said that on average those with diabetic neuropathy drove more slowly than the other groups tested, which would reduce the dangers of driving generally.
He suggested there may be scope for doctors and nurses to issue specific neuropathy motoring advice during consultations as they do for eyesight and blood sugar monitoring.
One of the other considerations of the team’s research is that the onset of diabetic neuropathy, as a complication of diabetes, can be very gradual.
An estimated nine per cent of the UK adult population have diabetes and half of these will experience symptoms of diabetic peripheral neuropathy, equating to a potential 1.5 million motorists.
Sufferers may not realise anything is wrong until they experience a loss of pain sensation in their foot or develop an ulcer, two of the common triggers for a diagnosis.
It means the development of associated driving difficulties may be just as gradual, and may go unnoticed by a driver, who could be using their vehicle unaware of the changes and possible dangers.
The Manchester Metropolitan team hopes the study’s findings will bring greater attention to the implications for driving of diabetic peripheral nerve damage and how to manage or reverse these changes in driving.
The majority of study participants became involved through Research for the Future, a National Institute for Health Research initiative, which helps recruit to research across Greater Manchester, hosted by Salford Royal Hospital, part of the Northern Care Alliance NHS Group.
Katherine Grady, service manager at Research for the Future said: “Lots of people living with diabetes were eager to participate in this study, which suggests this previously unexplored area of research is important to them.
“Symptoms of diabetic neuropathy typically develop over many months or years and can go unnoticed. This study highlights the importance of people with diabetes attending their annual foot check to detect potential problems early and receive appropriate advice from their healthcare team.”