Accelerator pedal control in diabetes: influence of ankle proprioception and muscle strength

Aims Diabetic peripheral neuropathy (DPN) influences neural sensitivity, nerve conduction velocity, proprioception and muscle strength. The aim of this work was to investigate whether the speed of strength generation (SSG) and/or proprioception function of the plantarflexor muscles in people with diabetes both with and without peripheral neuropathy would affect accelerator pedal control on a driving simulator. Methods Fifty-four active drivers, 15 with DPN (DPN, aged 66±6.0yrs), 25 with diabetes but no neuropathy (DM, aged 62±8.7yrs) and 14 controls without diabetes (C, aged 58±10yrs), undertook a maximum isometric muscle test of the plantarflexor muscles and a proprioception test of the right ankle joint using a dynamometer, in addition to a driving task using a driving simulator. We measured SSG (Nm/s), proprioception error values (degrees) and accelerator pedal position (degrees) from these tests, respectively. Results The DM and DPN groups showed significantly lower values for SSG with respect to C (DPN: 80.9±58.4; DM: 134.2±89.3; C: 233±135.4 Nm/s; p<0.05). The DPN group showed the highest proprioception error (DPN: 4.7±0.7; DM: 3.2±0.5; C: 3.2±0.68 deg; p>0.05), and the lowest value of accelerator pedal displacement during the driving test (DPN: 1.8±0.8; DM 3.1±0.6; C: 2.9±0.7 deg; p>0.05) with respect to DM and C groups. Conclusions Whilst not affecting people with diabetes without neuropathy, reduced ankle joint proprioception together with a slower production of plantarflexor muscle strength seems to influence accelerator pedal control during a driving simulation task in people DPN.