Diabetic peripheral neuropathy (DPN) is increasingly common among older Americans, with a prevalence approaching 15%, and is a potent risk factor for falls. Previous work has shown that older persons with DPN have functionally significant impairments in lower extremity sensory and motor function that impacts postural control. An irregular surface, which challenges postural control, is a common source of falls in this population. Moreover, measures of gait variability on an irregular surface more effectively differentiate between older persons with DPN and those without, and between older persons with DPN who fall and those who do not, than similar measures on a smooth surface. We hypothesize that feedback loop delay in ankle joint force output in response to a perturbation, related primarily to a DPN-associated impairment in rate of strength generation, is the mechanism by which DPN leads to postural instability, which in turn results in increased gait variability and fall risk. Therefore the aims of this research are: 1) To measure feedback loop delay in ankle joint force output in a group of 40 subjects (30 DPN, stratified by severity, and 10 healthy old) and determine its ability to predict postural responses to discrete perturbations, provided by a novel shoe, under the medial and lateral forefoot using kinematic and force plate data;2) To further evaluate the effect of feedback loop delay, utilizing the same subjects, by determining its ability to predict measures of gait variability on smooth and irregular surfaces;3) To investigate the extent to which measures of gait variability, determined separately on smooth and irregular surfaces, predict the incidence of falls and fall-related injuries observed prospectively over one year in a group of 100 subjects with DPN. The resulting research will provide insights into the mechanism by which DPN impairs recovery from surface irregularities and identify the gait measure best able to predict falls and fall-related injuries in this high risk population.

Public Health Relevance

Walking as a form of exercise is a common and important treatment of adult onset diabetes mellitus. However, many older patients with diabetes have nerve damage in their feet and legs that causes them to fall, particularly when walking on irregular surfaces. This research will identify the reasons that such patients fall, and which patients are at greatest risk of falling and being injured. This information will lead to strategies for making such patient safer while walking.

National Institute of Health (NIH)
National Institute on Aging (NIA)
Research Project (R01)
Project #
Application #
Study Section
Musculoskeletal Rehabilitation Sciences Study Section (MRS)
Program Officer
Joseph, Lyndon
Project Start
Project End
Budget Start
Budget End
Support Year
Fiscal Year
Total Cost
Indirect Cost
University of Michigan Ann Arbor
Physical Medicine & Rehab
Schools of Medicine
Ann Arbor
United States
Zip Code
Donaghy, Alex; DeMott, Trina; Allet, Lara et al. (2016) Accuracy of Clinical Techniques for Evaluating Lower Limb Sensorimotor Functions Associated With Increased Fall Risk. PM R 8:331-9
Nnodim, Joseph O; Kim, Hogene; Ashton-Miller, James A (2016) Dual-task performance in older adults during discrete gait perturbation. Exp Brain Res 234:1077-84
Richardson, James K (2016) Imbalanced: The Confusing Circular Nature of Falls Research… and a Possible Antidote. Am J Phys Med Rehabil :
Zurales, Katie; DeMott, Trina K; Kim, Hogene et al. (2016) Gait Efficiency on an Uneven Surface Is Associated with Falls and Injury in Older Subjects with a Spectrum of Lower Limb Neuromuscular Function: A Prospective Study. Am J Phys Med Rehabil 95:83-90
Nnodim, Joseph O; Yung, Raymond L (2015) Balance and its Clinical Assessment in Older Adults - A Review. J Geriatr Med Gerontol 1:
Allet, Lara; Kim, Hogene; Ashton-Miller, James et al. (2014) Step length after discrete perturbation predicts accidental falls and fall-related injury in elderly people with a range of peripheral neuropathy. J Diabetes Complications 28:79-84
Richardson, James K; Demott, Trina; Allet, Lara et al. (2014) Hip strength: ankle proprioceptive threshold ratio predicts falls and injury in diabetic neuropathy. Muscle Nerve 50:437-42
Nnodim, Joseph O; Kim, Hogene; Ashton-Miller, James A (2013) Effect of a vocal choice reaction time task on the kinematics of the first recovery step after a sudden underfoot perturbation during gait. Gait Posture 37:61-6
Kim, Hogene; Nnodim, Joseph O; Richardson, James K et al. (2013) Effect of age on the ability to recover from a single unexpected underfoot perturbation during gait: kinematic responses. Gait Posture 38:853-7
Richardson, James K; Allet, Lara; Kim, Hogene et al. (2013) Fibular motor nerve conduction studies and ankle sensorimotor capacities. Muscle Nerve 47:497-503

Showing the most recent 10 out of 18 publications