The Association Between STarT Back Tool Subgroups and Postural Stability
Condition: Low Back Pain, Postural
MeSH terms: Back Pain; Low Back Pain
Study type: Interventional

Summary: 
      Purpose This trial study the association between SBT subgroups and postural stability. It is
      theorized that cognitive impairment is more pronounced among patients in SBT group three
      compared to SBT group one and two. Therefore, it is hypothesized that challenging patients'
      balance will have a greater impact on the postural sway among patients in SBT group three
      compared to SBT group one and two in conditions where sensory information is reduced and
      cognitive load is increased.
    

Detailed description: 
      Globally low back pain (LBP) and neck pain are the leading causes of disability (1).
      Consequently, improvements in the assessment and treatment of LBP can have an extensive
      impact. Patients with LBP constitute a heterogeneous group and to improve treatment there is
      much focus on identifying subgroups of patients and tailor treatment accordingly. An example
      of this is the STarT Back Tool (SBT) which has been translated to more than 20 languages and
      is probably the most used tool for subgrouping of patients with LBP. The SBT sub-groups
      patients into three groups with a progressing need for treatment. Patients in group one
      should be given information on LBP and advice to stay active, patients in group two are also
      recommended supplementary treatment in primary care, and in addition patients in group three
      need attention to psycho-social issues (2-3). Accordingly to the SBT, patient in group three
      should be treated with cognitive therapy by a physiotherapist undergoing special training.
      This training includes mentorship and professional support to enable physiotherapists to
      elicit and address complex issues in patients with psycho-social barriers to recovery.
      Subgrouping by SBT and thereby treating patients in group three with cognitive therapy has
      been found effective in improving their functional outcomes (4-5).

      Patients with LBP have found to have different postural control strategies than patients
      without LBP especially during tasks involving increased task complexity (6-7). However, some
      studies have not found decreased postural control among patients whit LBP (8-9).
      Heterogeneous study populations may explain the discrepancy in findings especially if
      subgroups of patients with LBP have affected postural control while other subgroups are not
      affected.

      Patients with pain often present with some degree of cognitive impairments which could limit
      the extent to which daily activities could be performed. This may be particularly present
      among SBT group three patients. Cognitive impairments have been associated with decreased
      function and consequently reduced balance in elderly, indicating that postural stability
      requires significant amount of cognitive resource. Since the cognitive resources are limited,
      if additional tasks compete for these resources, performance in one or more tasks can become
      affected. The conscious interpretation of (or attention towards) painful stimulations is a
      costly process that uses significant amount of the cognitive resources available which could
      impair physical performance. Consequently, this may lead to additional postural sway and
      thereby restricted balance.

      After given written informed consent patients fill in a questionnaire including age, gender,
      educational level (bachelor, yes/no), employment, sick leave, co-morbidity (other than LBP,
      yes/no), pain duration (2-6 weeks/sub-acute or chronic), pain intensity (NPR), Roland Morris
      Disability Questionnaire (23 question, RMDQ), self-reported health status (EQ-5D visual
      analogue scale). After filling in the questionnaire patients will be asked to take of their
      jacket and shoes and to empty their pockets, before measuring height, weight, and testing for
      static balance.

      Postural sway will be measured using a force plate (Metitur Good Balance System®). The force
      plate will be placed with a distance of 100 cm to a wall in front of the patient and with
      more than 100 cm of free space to the sides and behind the force plate. The force plate, an
      equilateral triangle (800 mm), had four strain gauge transducer signals converted by a
      three-channel DC amplifier and transformed to digital data (50 Hz) and subsequently filtered
      digitally, using a three-point median filter and IRR filter, with 20 Hz cut-off frequency. On
      the wall in front of the patient a 12 cm circular green plate will be place in the patients'
      eye level. Patients will be asked to stand with their feet as closed positioned as possible,
      without lifting their feet, and to focus on the green plate in front of them. Patients will
      be asked to replicate this position for each test. The static balance test will require that
      the subjects stand as quiet as possible during 35 seconds in 4 different conditions in the
      following order: (i) eyes open and easy counting, (ii) eyes closed and easy counting, (iii)
      eyes closed and counting in multiples of seven, and (iv) eyes closed and counting backward
      from 500 in multiples of seven.

      The force platform, scale, and person altimeter will be calibrated every fortnight or more
      frequent. Data will be extracted, checked for any abnormal discrepancies, and saved on a
      secure driver frequently (at least every fortnight).
    

Intervention name(s): Static balance testing
Intervention type(s): Diagnostic Test
Intervention description(s): Postural sway will be measured using a force plate (Metitur Good Balance System®).
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: This is a double blinded experimental study comparing sub-groups of patients with low back pain
Masking: Triple (Participant, Investigator, Outcomes Assessor)
Primary purpose: Diagnostic