Evaluation of Endogenous Pain Modulation Mechanisms With Transcutaneous Electrical Nerve Stimulation
Condition: Chronic Pain
MeSH terms: Chronic Pain
Study type: Interventional

Summary: 
      A number of chronic pain conditions are characterized by imbalances in excitatory and/or
      inhibitory mechanisms and these deficits appear correlated with the response to certain
      treatments. Evaluating these mechanisms among people who suffer from chronic pain could allow
      clinicians to adapt the treatment to each patient according to the deficits observed. To
      evaluate excitatory and inhibitory mechanisms, a thermode (hot plate) and a cold water bath
      can be used (standardized protocol). Unfortunately, these tools are expensive, time-consuming
      and require complex equipment and software. As such, it is not realistic for clinicians to
      use them for routine patient assessment. A potential alternative to study these mechanisms is
      TENS (transcutaneous electrical nerve stimulation). TENS is frequently used in rehabilitation
      and unlike thermode and cold water bath, is affordable, easy to use and requires very little
      time and equipment. The objective of this study are to determine if the TENS can replace the
      thermode and cold water bath (standardized protocol) for the evaluation of excitatory and
      inhibitory mechanisms. Also, to determine if there will be a correlation with the
      standardized protocol. 50 healthy participants between 18 and 60 years old will participate
      in this study. Each participant will attend two experimental sessions. In one of the two
      sessions, the evaluation will be done with the TENS; in the other session, the evaluation
      will be done with the standardized protocol (thermode and cold water bath).
    

Detailed description: 
      To evaluate excitatory and inhibitory mechanisms, the investigators will used the modified
      CPM testing procedure consisting of test stimulus (TS) administered before and after a
      conditioning stimulus (CS). For the standardized protocol, the TS will consisted of a noxius
      heat stimulus generated by a thermode (hot plate), applied for two minutes on the
      non-dominant anterior forearm. The CS will consisted of a cold pressor test (CT), wherein
      participants immersed their dominant forearm in a cold water bath for two minutes. For the
      TENS protocol, the TS will consisted of a noxius electrical stimulus generated by TENS,
      applied for 5 seconds on the non-dominant knee at a frequency of 1 Hz and 5 Hz. The CS will
      consisted of a noxius electrical stimulus generated by TENS' applied for 120 seconds on the
      non dominant knee and ankle at a frequency of 2 Hz.
    

Intervention name(s): Thermode(hot plate) and cold water bath; TENS(transcutaneous electrical nerve stimulation)
Intervention type(s): Device; Device
Intervention description(s): Standardized protocol will consisted of stimulus test (TS) generated by thermode and conditioning stimulus (CS) using cold water bath.; TENS protocol will consisted of test stimulus (TS) and conditioning stimulus (CS) both generated by TENS
Allocation: Randomized
Intervention model: Crossover Assignment
Intervention model description: Participants will attended two experimental sessions at the Research Center on Aging of the Centre Intégré Universitaire de Santé et de Services Sociaux de l'Estrie, Sherbrooke, during which the efficacy of their excitatory and inhibitory mechanisms was assessed. In one session, this assessment was done using TENS protocol; in the other, using a standardized protocol (thermode and cold water bath). Session order was randomized between participants (randomization by block of 4 stratified by sex, using a random number table). The two sessions were separated by 24 to 72 hours and lasted approximately one hour each.
Masking: None (Open Label)
Primary purpose: Other
Keywords: Excitatory mechanisms; Inhibitory mechanisms; Thermode(hot plate); Cold water bath; Transcutaneous electrical nerve stimulation (TENS)