Electrical Stimulation With Interferential Current in the Non-especific Chronic Low Back Pain: Effects on the Autonomic Nervous System.
Condition: Chronic Low-back Pain; Chronic Pain; Autonomic Imbalance
MeSH terms: Back Pain; Low Back Pain; Chronic Pain
Study type: Interventional

Summary: 
      The aim of this study it's to analyze the relationship between autonomic nervous system
      balance (ANSb) and chronic pain conditions, especially in this case, non-especific chronic
      low back pain (CLBP).

      Most of physiotherapy approaches focus only in biomechanical aspects, leaving aside what kind
      of factors could perpetuate CLBP. Since 1985, ANSb was studied due to its potential
      contribution to chronic pain.

      Electrical stimulation, through interferential currents (IFC), it's a safe and well-known
      therapy used in CLBP with good outcomes regarding pain relief.

      The main objective of this study it's to quantify the association between CLBP and ANSb
      alterations. In second place, the research team aims to record the influence of IFC over pain
      and ANSb in those subjects.
    

Detailed description: 
      In the first place, a meeting will be organized with the patients to resolve any doubt about
      the study and its process. The investigators will make sure every instruction is
      understandable, giving enough time to read and ask pertinent questions.

      Secondly, patients will be provided of an informed consent specific for the present study,
      according to the legal forms. Participants must agree with all the information and sign the
      document.

      At this point, patients will be interviewed individually by a researcher to collect all the
      data regarding to the Clinical History in Physiotherapy.

      In the next step, patients will be randomized into two different groups by choosing one
      opaque envelope, containing a number for the allocation. A researcher will make the final
      allocation depending on the number. Patients were unaware of the group allocation for
      masking.

      This study has to possible groups with a common indication for both:

        1. Experimental group: Patients allocated in this group will receive one single session of
           interferential current (IFC). Current used a carrier frequency of 4.000 Hz, 65Hz of
           amplitude modulated frequency (AMF) with sweep frecuency of 95Hz in a 1:1 swing pattern
           (quadripolar technique). Intensity was adjusted according to patient's tolerance without
           visible muscle twitches. The session will last 25 min.

        2. Control group: This group will receive the same intervention than experimental one but
           with no intensity, for 25 minutes. Patients will keep his general practitioner's
           indications about pharmacology.

        3. Common indication: Both groups will get instructions to perform a set of home-based
           exercises for core strengthening after variable collecting.

      Before and after the session, all the variable measurements will be collected in the same
      environmental conditions by the same researcher. Basal measurement (before intervention) will
      be recorded 15 minutes before session for 10 minutes. The second measurement will be taken
      while the patient recieves the intervention for 20 minutes.
    

Intervention name(s): Electrical stimulation: Interferential Current (IFC): Experimental Group; Electrical stimulation: Interferential Current (IFC): Control Group
Intervention type(s): Device; Device
Intervention description(s): Application of IFC with Sonopuls 692® (Enraf-Nonius BV, Rotterdam, The Netherlands) device. Parameters:
Carrier frequency of 4000 Hz
Amplitude modulated frequency of 65 Hz (AMF)
Sweep frequency of 95 Hz of modulation with a 1:1 swing pattern, in a quadripolar technique.
Intensity will depend on subjet's tolerance but without generate visible muscle twitches.
Session duration: 25 minutes; Application of IFC with Sonopuls 692® (Enraf-Nonius BV, Rotterdam, The Netherlands) device. Parameters:
Carrier frequency of 4000 Hz
Amplitude modulated frequency of 65 Hz (AMF)
Sweep frequency of 95 Hz of modulation with a 1:1 swing pattern, in a quadripolar technique.
NO intensity (0 mA)
Session duration: 25 minutes
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Participants diagnosed with chronic low back pain will be divided into two different groups with 28 patients each:
Experimental group: Participants in this group will receive electrical stimulation with interferential current. They will get also instructions to perform core strengthening exercises at home, after variable collection.
Control group: Participants in this group will recieve the same electrical stimulation than in the experimental group but with no intensity. This group will get too instructions to perform core strengthening exercises at home (after variable collection) and follow General Practitioner indications about pharmacology.
Masking: Single (Participant)
Primary purpose: Basic Science
Keywords: electrical stimulation; interferential current; autonomic balance; chronic low back pain