H-reflex amplitude depression as a marker of presynaptic inhibition in Painful Diabetic Neuropathy (PDN)
Abstract: Painful Diabetic
Neuropathy (PDN) is a common complication of diabetes mellitus (DM). Disruption
in presynaptic inhibition in dorsal horn of the spinal cord has been proposed
as one of the pathomechanism of PDN. Previous research showed that presynaptic
inhibition can be detected by H-reflex examination. The aim of this study was
to know whether the reduction of presynaptic inhibition in spinal dorsal horn
of PDN patients really exist, and detectable by H-reflex examination. It was
cohort prospective involving 141 (58 men, 83 women) patients with DM and
impaired glucose tolerance (IGT) between the ages of 40 and 61 years from
several health facilities in Yogyakarta. All patients underwent clinical,
laboratory and electrodiagnostic examination. Demographic, clinical and
electrodiagnostic data were collected and analyzed. By survival analysis there
were 25 new cases of PDN (12.12% cumulative incidence). Using survival Kaplan
Meier analysis, the significant hazard ratio for PDN were 12.81 for median motor
nerve amplitude, 5.74 for median nerve distal latency, 3.71 for median sensory
nerve amplitude, 6.33 for median sensory latency, 3.4 for tibial nerve
amplitude, 3.48 for tibial nerve distal latency, 2.29 for sural nerve
amplitude, 4.47 for sural nerve latency, 3.99 for H-reflex latency, 5.88 for
H-reflex amplitude, and 17.83 for Diabetic Neuropathy (DN) status. Using hazard
proportional cox analysis, only H amplitude and DN status (DNS score) were
significantly correlated with PDN (p= 0.026; hazard ratio = 15.450; CI 95%=
1.39 – 171.62 for H amplitude and p= 0.030; hazard ratio = 10.766; CI 95%=1.26
– 92.09 for DN status).
This study showed that depression of H-reflex amplitude was correlated
with the occurrence of PDN. This result proves that there was presynaptic
inhibition process in PDN that manifests as low H-reflex amplitude.
Keywords: Painful diabetic
neuropathy - H-reflex amplitude - presynaptic inhibition - Diabetes Mellitus
Author: Ahmad Asmedi, Samekto
Wibowo, Lucas Meliala
Journal Code: jpkedokterangg150353
