The effect of sensory nerve stimulation on sensory nerve function in people with peripheral neuropathy associated with diabetes

To assess the effect of sensory nerve stimulation in older people with peripheral neuropathy associated with diabetes (DPN).A randomized, placebo controlled, double blind trial was used to assess the effect of 12 weeks of low frequency sensory nerve stimulation (LF-SNS) in the lower limb [International Patent Application No. PCT/AU2004/001079: 'nerve function and tissue healing' (Z. Khalil)]. Response to capsaicin, basal microvascular blood flow, electric cutaneous threshold and oxygen tension were assessed pre- and post-treatment and between limbs.People 55 years of age or older diagnosed with DPN: 35 active and 31 placebo participants.Between groups comparisons: no significant differences occurred between stimulation groups. Within subject comparisons: in the active LF-SNS group, comparing stimulated to contralateral legs, there were significant increases in size of capsaicin flare [t(1,33)=3.65, p0.05] and capillary blood flow [t(1,34)=-0.33, p0.05]. There was a trend to improvement in time to initial flare response [t(1,34)=-1.86, p=0.07]. No changes were evident in the placebo group. RESPONDER ANALYSES: In a group of 'responders', the time to initial flare response (p0.05, r=0.64), size of capsaicin flare (p0.05 r=1.0) and microvascular blood flow (p0.05, r=0.60) improved significantly after LF-SNS.The observed data suggest that LF-SNS improves nerve function in a subset of people with DPN. Targeting toward probably 'responders' may deliver the greatest benefit from short-term therapy. Testing optimal application in others seems warranted.