Trigeminal nociceptive function and oral somatosensory functional and structural assessment in patients with diabetic peripheral neuropathy

Y M Costa,J R Nyengaard,L Baad-Hansen,P Svensson,P Karlsson,T S Jensen,H Tankisi,P C R Conti,L R Bonjardim

doi:10.1038/s41598-018-37041-4

Abstract

This case-control study primarily compared the trigeminal nociceptive function, the intraoral somatosensory profile and possible structural nerve changes between diabetic peripheral neuropathy (DPN, n = 12) patients and healthy participants (n = 12). The nociceptive blink reflex (nBR) was recorded applying an electrical stimulation over the entry zone of the right supraorbital (V1R), infraorbital (V2R) and mental (V3R) and left infraorbital (V2L) nerves. The outcomes were: individual electrical sensory (I0) and pain thresholds (IP); root mean square (RMS), area-under-the-curve (AUC) and onset latencies of R2 component of the nBR. Furthermore, a standardized full battery of quantitative sensory testing (QST) and intraepidermal nerve fibre density (IENFD) or nerve fibre length density (NFLD) assessment were performed, respectively, on the distal leg and oral mucosa. As expected, all patients had altered somatosensory sensitivity and lower IENFD in the lower limb. DPN patients presented higher I0, IP, RMS and AUC values (p < 0.050), lower warm detection thresholds (WDT) (p = 0.004), higher occurrence of paradoxical heat sensation (PHS) (p = 0.040), and a lower intraoral NFLD (p = 0.048) than the healthy participants. In addition, the presence of any abnormal intraoral somatosensory finding was more frequent in the DPN patients when compared to the reference group (p = 0.013). Early signs of trigeminal nociceptive facilitation, intraoral somatosensory abnormalities and loss of intraoral neuronal tissue can be detected in DPN patients.

Highlights

Diabetic peripheral neuropathy (DPN) is a well-known complication and is estimated to occur in 10–90% of type 1 and/or type 2 diabetes patients[1]
The nociceptive blink reflex (nBR) is an electrophysiological test that can be used to evaluate the trigeminal nociceptive function with the aid of concentric surface electrodes that yield a more selective activation of nociceptive fibres[9], whereas quantitative sensory testing (QST) encompasses a standard battery of psychophysical tests that provide a comprehensive phenotyping of the somatosensory function[12]
We hypothesized a priori that there would be a difference between DPN patients and healthy participants regarding the electrophysiological and functional somatosensory and structural assessment of the trigeminal region

Summary

Introduction

Diabetic peripheral neuropathy (DPN) is a well-known complication and is estimated to occur in 10–90% of type 1 and/or type 2 diabetes patients[1]. Since the beginning of the 21st century, techniques and methods for comprehensive investigation of the trigeminal system with focus on sensory function in general, and nociceptive function in particular, have become more accessible and accepted in the clinical and research environment[3,4,5] This is mainly due to extensive work on establishing the validity and reliability of techniques for the orofacial region assessment, e.g. nociceptive blink reflex (nBR)[6,7,8,9] and quantitative sensory testing (QST)[10,11,12,13]. We hypothesized a priori that there would be a difference between DPN patients and healthy participants regarding the electrophysiological and functional somatosensory and structural assessment of the trigeminal region

Objectives

Methods

Results

Conclusion