The aim of this work was to identify relationships between complex and simple clinical measures of reaction time (RTclin) and indicators of balance in older subjects with and without diabetic peripheral neuropathy (DPN).
Prospective cohort design. Complex RTclin accuracy, simple RTclin latency, and their ratio were determined using a novel device in 42 subjects (mean ± SD age, 69.1 ± 8.3 yrs), 26 with DPN and 16 without. Dependent variables included unipedal stance time (UST), step width variability and range on an uneven surface, and major fall-related injury over 12 months.
In the DPN subjects, the ratio of complex RTclin accuracy to simple RTclin latency was strongly associated with longer UST (R/P = 0.653/0.004), and decreased step width variability and range (R/P = −0.696/0.001 and −0.782/<0.001, respectively) on an uneven surface. Additionally, the 2 DPN subjects sustaining major injuries had lower complex RTclin accuracy:simple RTclin latency than those without.
The ratio of complex RTclin accuracy:simple RTclin latency is a potent predictor of UST and frontal plane gait variability in response to perturbations and may predict major fall injury in older subjects with DPN. These short latency neurocognitive measures may compensate for lower limb neuromuscular impairments and provide a more comprehensive understanding of balance and fall risk.
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From the Department of Physical Medicine and Rehabilitation, University of Michigan, Ann Arbor, Michigan.
All correspondence and requests for reprints should be addressed to: James K. Richardson, MD, Department of Physical Medicine and Rehabilitation, University of Michigan, 325 E Eisenhower Parkway, Suite 2000, Ann Arbor, MI 48018.
Financial disclosure statements have been obtained, and no conflicts of interest have been reported by the authors or by any individuals in control of the content of this article.
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