Correlation of current perception threshold and somatosensory evoked potential in diabetes

To study the relationship between current perception threshold (CPT) and somatosensory evoked potential (SEP) in diabetes.

Both CPT and SEP were recorded in 66 diabetic patients. Both the CPT scores (measured at 2000 Hz, 250 Hz, and 5 Hz stimulations) and SEP (peak latency at ERB's point [Lat (ERB)] and popliteal fossa [Lat (PF)]; interpeak latency of "ERB to 7th cervical vertebra" [Δlat (ERB-C7)] and "popliteal fossa to lumbar vertebra" [Δlat (PF-FO)]) were recorded in both upper and both lower limbs, separately. t-tests and correlation analyses were performed to assess relationships between CPT and SEP tests.

After adjustment for height and/or age, CPT scores at 2000 Hz were significantly correlated with Lat (ERB) (left: ρ=0.408, P<0.05; right: ρ=0.297, P<0.05), Δlat (ERB-C7) (left: ρ=0.238, P<0.05; right: ρ=0.385, P<0.05), and Lat (PF) (ρ=0.216, P<0.05), and those at 250 Hz were moderately correlated with Lat (ERB) (left: ρ=0.234, P<0.05; right: ρ=0.306, P<0.05). CPT scores at 5 Hz were not significantly correlated with any SEP measurements (P>0.05).

Both CPT scores at 2000 Hz and SEP may reliably determine large-fiber function in diabetic neuropathy.