A new method of screening for diabetic neuropathy using laser Doppler and photoplethysmography.
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.
Kim
Sung Woo
SW
Department of Medical Engineering, College of Medicine, Yonsei University, Seoul, South Korea.
Kim
Soo Chan
SC
Nam
Ki Chang
KC
Kang
Eun Seok
ES
Im
Jae Jung
JJ
Kim
Deok Won
DW
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