title: Validation of the modified LDIFlare technique: a simple and quick method to assess C-fiber function.
abstract: BACKGROUND
  In this study we validated a modified laser Doppler imager method (mLDIf) for assessing C-fiber function and compared it to the original (oLDIf). Both measure flare size in foot skin after heating, but the mLDIf uses 47°C (vs. 44°C), making it quicker and better suited for clinical use.
  
  
  METHODS
  To confirm that mLDIf assesses C-fiber function, 5 healthy controls (HC) were studied before and after local anesthesia (LA). Reproducibility and comparison with oLDIf was assessed in HC (n = 16). Finally, diabetes subjects with (DN(+), n = 10) and without (DN(-), n = 16) neuropathy were studied.
  
  
  RESULTS
  LA almost abolished the flare (9.3 ± 3.0 cm(2) vs. 1.7 ± 0.3 cm(2), P < 0.0001). mLDIf produced larger flares (9.9 ± 3.4 vs. 5.7 ± 2.3 cm(2), P < 0.0001), but correlated with oLDIf (r = 0.81, P < 0.001). mLDIf was reduced in DN(-) (6.8 ± 2.8 vs. HC, P = 0.003), markedly so in DN(+) (2.0 ± 1.1 vs. HC and DN(-), P < 0.0001).
  
  
  CONCLUSIONS
  The mLDIf is a quick, practical method for assessing C-fiber function in the clinical setting.
authors.affiliation: Diabetes Research Centre, Ipswich Hospital NHS Trust, Suffolk IP4 5PD, UK.
authors.forename: Prashanth R J
authors.initials: PR
authors.lastname: Vas
authors.forename: Gerry
authors.initials: G
authors.lastname: Rayman
mesh_terms: D000328:Adult; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology; D003929:Diabetic Neuropathies / Q000175:diagnosis*; D005260:Female; D005528:Foot / Q000294:innervation; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D036421:Nerve Fibers, Unmyelinated / Q000502:physiology*; D059906:Neuroimaging; D010147:Pain Measurement / Q000379:methods; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis*; D015203:Reproducibility of Results; D012867:Skin / Q000293:injuries