title: A new method of screening for diabetic neuropathy using laser Doppler and photoplethysmography.
abstract: The purpose of this study is to suggest a simple, new method of screening for diabetic neuropathy. We measured blood volume changes by photoplethysmography (PPG) and blood perfusion by laser Doppler (LD) in the index fingers and big toes in 40 control subjects and in 50 (19 mild, 17 moderate, and 14 severe based on the nerve conduction velocity (NCV) test) and 35 diabetic patients with and without neuropathy, respectively. According to the results of PPG and LD measurements, the toe to finger ratios obtained from the neuropathic group were significantly higher than those from the control (p < 0.001) and the non-neuropathic groups (p < 0.001). Based on the NCV, the sensitivity of the LD method (92.0%) was higher than that of the PPG method (84.0%) for both left and right sides. Although specificity of the LD (92.8%) was also higher than the PPG (84.3%) bilaterally, the PPG showed better reproducibility (5.5 versus 9.5%) and a significant ratio increase with severity, while the LD did not. Our suggested PPG method using the toe to finger ratio is reliable, simple, economical, and accurate, and could become an effective new screening tool for the early detection of diabetic neuropathy.
authors.affiliation: Department of Medical Engineering, College of Medicine, Yonsei University, Seoul, South Korea.
authors.forename: Sung Woo
authors.initials: SW
authors.lastname: Kim
authors.forename: Soo Chan
authors.initials: SC
authors.lastname: Kim
authors.forename: Ki Chang
authors.initials: KC
authors.lastname: Nam
authors.forename: Eun Seok
authors.initials: ES
authors.lastname: Kang
authors.forename: Jae Jung
authors.initials: JJ
authors.lastname: Im
authors.forename: Deok Won
authors.initials: DW
authors.lastname: Kim
mesh_terms: D000368:Aged; D001810:Blood Volume; D003929:Diabetic Neuropathies / Q000175:diagnosis*; D005260:Female; D005385:Fingers / Q000098:blood supply; D006801:Humans; D017078:Laser-Doppler Flowmetry / Q000379:methods; D008297:Male; D008403:Mass Screening / Q000379:methods; D008875:Middle Aged; D017156:Photoplethysmography / Q000379:methods; D012680:Sensitivity and Specificity; D012881:Skin Temperature; D014034:Toes / Q000098:blood supply