Complex and Simple Clinical Reaction Times Are Associated with Gait, Balance, and Major Fall Injury in Older Subjects with Diabetic Peripheral Neuropathy

Abstract

Objective 

The aim of this work was to identify relationships between complex and simple clinical measures of reaction time (RT_clin) and indicators of balance in older subjects with and without diabetic peripheral neuropathy (DPN).

Design 

Prospective cohort design. Complex RT_clin accuracy, simple RT_clin 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.

Results 

In the DPN subjects, the ratio of complex RT_clin accuracy to simple RT_clin 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 RT_clin accuracy:simple RT_clin latency than those without.

Conclusions 

The ratio of complex RT_clin accuracy:simple RT_clin 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.