Using Transcutaneous Electrical Nerve Stimulation (TENS) to Relieve Pain and Potentiate the Rehabilitation of Pain Patients: a Double Blind, Randomized Study Among Patients at the CSSS-IUGS Day Hospital

Introduction Chronic pain affects more than half of elderly individuals. Past studies have shown that pain can interfere with motor learning and rehabilitation. This phenomenon, potentially attributable to the deleterious effect that nociceptive inputs have on the motor system, suggests that relieving pain before physical therapy sessions might be an interesting strategy to potentiate the rehabilitation of older patients suffering from pain.

Objective The objective of this study is to determine if the analgesic effect induced by transcutaneous electrical nerve stimulation (TENS) can be used to maximize the rehabilitation of elderly patients suffering from chronic pain. More specifically, this study aims to: 1) compare functional outcomes of patients from the Day Hospital receiving rehabilitation with active TENS treatments with patients receiving rehabilitation with simulated TENS treatments, and 2) determine if there is an association between the analgesic effect of TENS and the clinical evolution of patients following their rehabilitation.

Methods This study is a randomized clinical trial with two parallel arms. Patients will be assigned randomly to either the: 1) experimental group receiving active TENS treatments or 2) the control group receiving simulated TENS treatments (double blind study). Thirty-six patients will be recruited according to the following criteria: 1) will receive physiotherapy rehabilitation at the Day Hospital of the Pavillon d'Youville of the CSSS-IUGS, 2) be at least 65 years of age, 3) suffering from chronic pain (pain lasting for more than 6 months), 4) presenting pain during the rehabilitation at the Day hospital. For security reasons, patients with a cardiac simulator will be excluded from the present study (TENS contraindications). Patients with cognitive alterations (score of < 24/30 at the Folstein test) will also be excluded. In order to have a better characterisation of the sample, information will be retrieved from medical records by the research assistant, including: 1) age, gender, pain localisation, medical diagnosis and medication. Moreover, various questionnaires will be administered at baseline (T1), after half of the rehabilitation period (i.e. 4 to 6 weeks) (T2), and after the 8- to 12- week rehabilitation period (T3) to measure: 1) the qualitative aspects of pain (McGill-Melzack pain questionnaire), 2) mood (Beck Depression Inventory), and 3) physical function (Brief Pain Inventory). Functional outcomes will also be collected directly from the medical record at baseline at each assessment times (T1, T2, T3). The measures include: 1) exercise tolerance (6-minute walk test [6MWT]), 2) balance (Berg Balance Scale [BBS]), 3) mobility and balance (Time up and go [TUG]), and 4) functional ability (Functional autonomy measurement system [SMAF]).

Anticipated results We believe that: 1) use of active TENS during rehabilitation sessions will potentiate rehabilitation of patients suffering from chronic pain at the CSSS-IUGS Day Hospital, and 2) there is a relationship between the analgesic effect induced by TENS and the clinical evolution of patients.