Driving with Neuropathy

This study is a proof-of-concept randomised controlled trial (RCT). The goal of the study is to investigate the effectiveness of a feedback intervention to improve use of the accelerator pedal in patients driving with diabetes and peripheral neuropathy (DPN). The main (primary) question it aims to answer is: What is the effect of a visual feedback intervention (over 6 sessions a month apart), compared to no feedback, on accelerator pedal use by drivers with diabetic peripheral neuropathy? Our working hypothesis is that the visual feedback intervention will reduce the % of drive time with the accelerator pedal pushed down further than 9 degrees (about halfway down), the point at which the visual feedback (a warning signal) is triggered. Secondary research questions are: 1. What is the effect of the feedback intervention on drivers with diabetic peripheral neuropathy at the first visit, and at the third visit? When does the biggest improvement happen? Our working hypothesis is that the visual feedback intervention will reduce the % of drive time spent driving with the accelerator pedal pushed down further than 9 degrees, the point at which the feedback is triggered, in the first visit (ie with the first exposure to feedback) and by additional amounts in subsequent visits ie there will be an immediate benefit, and additional benefits that accrue gradually with repetition over the 6 monthly visits. 2. What is the effect of the feedback intervention on a second variable, % of drive time with the vehicle 'out of control'. Out of control is defined as extreme use of the steering wheel, large and rapid movements that reach the full range of motion of the steering wheel or large swings back and forth together with excursion out of lane which the driver fails to prevent. Our working hypothesis is that the visual feedback intervention will reduce the % of drive time with the vehicle out of control. Researchers will compare the group of drivers with neuropathy who receive the intervention with a control group who do not. In addition, a group of drivers who have diabetes but no diagnosed neuropathy will be studied. This is to seek confirmatory evidence (previously seen in a small sample in a previous study) that most drivers who have no diagnosed neuropathy do not push the accelerator pedal down more than 9 degrees and so do not need to improve their use of the accelerator pedal. Participants will have their driving assessed in a driving simulator. Participants with DPN who push the accelerator pedal down more than 9 degrees will then be randomly allocated to the intervention group or control group. Only drivers in the intervention group will go on to experience the visual feedback intervention (in 6 sessions a month apart). Drivers in the control group will have their driving assessed at their first visit, and then at two later visits timed to coincide with the 3rd and 6th visit by drivers in the intervention group. This is the minimum necessary to be able to compare their driving with the intervention group at the start, midpoint and end of the intervention.