title: Virtualizing the assessment: a novel pragmatic paradigm to evaluate lower extremity joint perception in diabetes.
abstract: BACKGROUND
  Individuals with diabetes have a higher risk of falls and fall-related injuries. People with diabetes often develop peripheral neuropathy (DPN) as well as nerve damage throughout the body. In particular, reduced lower extremity proprioception due to DPN may cause a misjudgment of foot position and thus increase the risk of fall.
  
  
  OBJECTIVE
  An innovative virtual obstacle-crossing paradigm using wearable sensors was developed in an attempt to assess lower extremity position perception damage due to DPN.
  
  
  METHODS
  67 participants (age 55.4 ± 8.9, BMI 28.1 ± 5.8) including diabetics with and without DPN as well as aged-matched healthy controls were recruited. Severity of neuropathy was quantified using a vibratory perception threshold (VPT) test. The ability of perception of lower extremity was quantified by measuring obstacle-crossing success rate (OCSR), toe-obstacle clearance (TOC), and reaction time (T(R)) while crossing a series of virtual obstacles with heights at 10% and 20% of the subject's leg length.
  
  
  RESULTS
  No significant difference was found between groups for age and BMI. The data revealed that DPN subjects had a significantly lower OCSR compared to diabetics with no neuropathy and controls at an obstacle size of 10% of leg length (p < 0.05). DPN subjects also demonstrated longer T(R) compared to other groups and for both obstacle sizes. In addition, TOC was reduced in neuropathy groups. Interestingly, a significant correlation between T(R) and VPT (r = 0.5, p < 10(-3)) was observed indicating a delay in reaction with increasing neuropathy severity. The delay becomes more pronounced by increasing the size of the obstacle. Using a regression model suggests that the change in T(R) between obstacle sizes of 10% and 20% of leg length is the most sensitive predictor for neuropathy severity with an odds ratio of 2.70 (p = 0.02).
  
  
  CONCLUSIONS
  The findings demonstrate proof of a concept of virtual-reality application as a promising method for objective assessment of neuropathy severity, however a further study is warranted to establish a stronger relationship between the measured parameters and neuropathy.
authors.affiliation: Center for Lower Extremity Ambulatory Research, Scholl College of Podiatric Medicine, Rosalind Franklin University of Medicine and Science, North Chicago, IL, USA.
authors.forename: Gurtej
authors.initials: G
authors.lastname: Grewal
authors.forename: Rashad
authors.initials: R
authors.lastname: Sayeed
authors.forename: Steve
authors.initials: S
authors.lastname: Yeschek
authors.forename: Robert Alexander
authors.initials: RA
authors.lastname: Menzies
authors.forename: Talal K
authors.initials: TK
authors.lastname: Talal
authors.forename: Lawrence A
authors.initials: LA
authors.lastname: Lavery
authors.forename: David G
authors.initials: DG
authors.lastname: Armstrong
authors.forename: Bijan
authors.initials: B
authors.lastname: Najafi
mesh_terms: D000058:Accidental Falls / Q000517:prevention & control; D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology / Q000523:psychology; D016022:Case-Control Studies; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology / Q000523:psychology; D003929:Diabetic Neuropathies / Q000503:physiopathology / Q000523:psychology*; D005260:Female; D006801:Humans; D007596:Joints / Q000503:physiopathology; D007866:Leg; D008297:Male; D008875:Middle Aged; D011434:Proprioception / Q000502:physiology*; D012307:Risk Factors; D012649:Self Concept; D014584:User-Computer Interface