Establishing Normative Values for Thermal Detection and Pain Threshold Established by the Psi Method

Summary

The study aims to compare different methods to assess thermal detection ability in diabetic patients, as a way to monitor and diagnose neurological complications of diabetes mellitus.

Conditions

• Small Fiber Neuropathy

Interventions

DIAGNOSTIC_TEST

Thermal QST (CDT, WDT, CPT, HPT) with the method of limits

The testing will be carried out using the classical method of limits, i.e. a continuous heating/cooling stimulus will be applied to the skin at a rate of 1°C/s, until the subject signals that he/she felt the targeted sensation by pressing a button (Rolke, Baron, et al., 2006). The temperature reached by the time the subject pressed the button will be considered the threshold. Baseline temperature will be set at 32°C. The stimuli will not go lower than 0°C and higher than 50°C.

DIAGNOSTIC_TEST

Thermal QST (cold and warm detection, heat pain) with the psi method

The Psi algorithm is a method using Bayesian statistics to determine not only the threshold but also the slope of the psychometric function (relationship between the intensity of a stimulus and its detection probability; Kingdom \& Prins, 2010). The algorithm selects the next stimulus intensity to be the most informative on the parameters of interest, based on the prior probability density. After each stimulation, the subject will be asked if he/she felt it (as painful) or not. Based on that answer, a posterior probability density is computed. This posterior is then used as prior for the next stimulation. The stimuli will last maximum 1 s and temperature will be kept between 0°C and 60°C.

DIAGNOSTIC_TEST

Neurological examination

A standardized neurological examination will be performed to assess all the items included in the Utah Early Neuropathy Scale (UENS ) (Singleton et al., 2008) and the Toronto Clinical Neuropathy Score (TCNS)(Perkins, Olaleye, Zinman, \& Bril, 2001). This will include: questions about symptoms (presence or absence of foot pain, numbness, tingling, weakness, imbalance and upper limb symptoms); evaluation of knees and ankles deep tendon reflexes; evaluation of pinprick, temperature, light touch, vibration (128 Hz tuning fork) compared to that of an unaffected sites (e.g., sternum); position sensation in the big toes; mapping of pinprick sensitivity in the lower leg; and evaluation of the active extension of the big toes. Pinprick evaluation will be performed using a disposable pin designed for that purpose (Medipin, The United-Kingdom).

Sponsors & Collaborators

• Cliniques universitaires Saint-Luc- Université Catholique de Louvain

  collaborator OTHER

• Université Catholique de Louvain

  lead OTHER

Principal Investigators

• André Mouraux, MD, PhD · Université Catholique de Louvain

Study Design

Allocation

NA

Purpose

DIAGNOSTIC

Masking

NONE

Model

SINGLE_GROUP

Eligibility

Min Age

40 Years

Max Age

79 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2020-10-10

Primary Completion

2022-07-01

Completion

2023-01-01

Countries

• Belgium

Study Locations