Concomitant Involvement of the Spinal Cord and the Thalamus in Diabetic Distal Symmetrical Sensorimotor Polyneuropathy
Abstract Number: 972-P
Authors: DINESH SELVARAJAH, IAIN D. WILKINSON, RAJIV GANDHI, CELIA J. EMERY, SOLOMON TESFAYE
Institutions: Sheffield, United Kingdom
Results: Involvement of the central nervous system in diabetic sensorimotor neuropathy (DN) is being increasingly recognised. We have previously demonstrated the presence of spinal cord atrophy not only in subjects with established-DN but also in early, subclinical DSP. In a further proton magnetic resonance spectroscopy (H+MRS) study, subjects with established-DN were found to exhibit thalamic neuronal dysfunction. In this study we looked at the relationship between spinal cord atrophy and thalamic neuronal function in DSP.
METHODS: Twenty subjects [6 healthy volunteers; 14 diabetic subjects (8 No-DN and 6 Established-DN)] underwent detailed assessment of peripheral nerve function including: neuropathic symptom evaluation, clinical examination to determine the Neuropathy Impairment Score of Lower Limbs (NIS[LL]), 5 attributes of nerve electrophysiology, vibration detection threshold and heart rate with deep breathing test. MR imaging of the cervical spine and thalamic H-MRS were conducted within one year. Cervical cord cross-sectional area at disc level C2/C3 was calculated. Established markers of neuronal function [N-acetyl aspartate:choline (NA:Cho)] were obtained from the thalamus using long echo time H+MRS.
RESULTS: Subjects with Established-DN had significant reduction in both cervical cord area [ANOVA p=0.002; Established-DN mean(SD) 52.1(4.1) vs No-DSP 68.8(8.20), p=0.001 and Established-DN vs HV 68.7(10.4), p=0.002] and thalamic NA:Cho [ANOVA p=0.013; Established-DN 1.58(0.16) vs No-DN 1.80(0.15) and Established-DN vs HV 1.74(1.0)] compared to the other groups. Among subjects with diabetes, cervicalcord area was significantly related to thalamic NA:Cho (r=0.42, p=0.04).
CONCLUSIONS: Diabetic subjects with Established-DN had the greatest level of spinal cord atrophy and thalamic neuronal dysfunction compared those with No-DN and HV. Significant positive correlations between spinal cord area and thalamic NA:Cho suggest progressive, concomitant involvement of the central nervous system in DN. Diabetes is a metabolic/vascular disorder and its insult on the nervous system appears more generalised, involving both the peripheral and central nervous systems.