Reliability of a Gait Analysis System
Condition: Gait Analysis
Study type: Observational

Summary: 
      Gait disturbances can be observed in all age groups, and may be due to different conditions,
      such as advanced age, stroke, head trauma, spinal cord injury, cerebral palsy,
      myelomeningocele, among others. The aforementioned gait disorders are associated with an
      increased risk of falls (which can cause major fractures or head trauma), decreased mobility,
      loss of independence, cardiovascular pathology, and decreased quality of life. In order to
      improve a given abnormal gait pattern, an objective assessment of gait is necessary. There
      are several methods to carry out gait evaluations, like Instrumented Gait Analysis (High
      cost, time-consuming, qualified professionals needed) and the ones based on observation
      (limited reliability and validity). An alternative, is the use of video-based systems. SILEMA
      (Computer System for Gait Study Laboratories in Argentina) is a video-based low-cost gait
      analysis system that measures temporo-spatial (speed, step length, cadence, stance and swing
      times) and joint kinematic (Hip, Knee, Ankle) parameters. Its reliability has not been
      reported yet; thus the primary aim of this study is to determine both the "intra-evaluator"
      (same evaluator, different sessions) and "inter-evaluator" (same session, different
      evaluators) reliability.
    

Detailed description: 
      Gait disturbances can be observed in all age groups, and may be due to different conditions,
      such as advanced age, stroke, head trauma, spinal cord injury, cerebral palsy,
      myelomeningocele, among others. The aforementioned gait disorders are associated with an
      increased risk of falls (which can cause major fractures or head trauma), decreased mobility,
      loss of independence, cardiovascular pathology, and decreased quality of life.

      One of the main objectives of rehabilitation is the improvement of the gait pattern, for
      which a correct evaluation of it is a necessary condition. Gait analysis is the systematic
      study of human locomotion, with joint kinematics (description of movement in different
      planes) and temporo-spatial parameters (speed, cadence, step length, stance and swing times)
      being variables usually valued and reported. There are several methods for conducting gait
      assessments. One of them consists of the administration of scales based on observation, which
      are accessible and simple to execute, but exhibit limited reliability and validity, depending
      in addition to the previous experience of the observer. The method considered "Gold standard"
      is the Instrumented Gait Analysis (IGA), from which parameters of kinematics (through
      optoelectronic cameras and reflective markers), kinetics (through the use of force platforms)
      and muscle activity (using electromyography) can be obtained.Unfortunately, these systems are
      not available in most rehabilitation centers, due to the high cost they represent, the need
      to have highly trained professionals for their use and the long time needed for calibration
      and post-processing, difficulties that are continuously mentioned in the literature. An
      alternative to IGA is the use of video-based systems that allow the quantification of
      temporo-spatial parameters and joint kinematics. One of these systems is SILEMA(Computer
      System for Gait Study Laboratories in Argentina) which is based on the technique of digital
      videography. This system exhibits the advantages of being portable, easy to implement and
      use, and low cost.The purpose of the clinical analysis of gait is usually to differentiate
      between normal and abnormal patterns, and to assess the change over time or due to an
      intervention (surgery, orthosis, botulinum toxin, physical therapy, etc.), being necessary in
      the latter case to make repeated measurements. Usually, to carry out gait evaluations, the
      patient is asked to perform several "passes", each of them consisting of a free gait through
      a walkway, at a "self-selected" speed, during a session in which the corresponding
      information is collected. In healthy subjects, there is usually a variability between
      repeated measurements (both intra-subject and inter-subject), which occurs at the expense of
      intrinsic factors (age, height, gait speed, etc.) or extrinsic, caused by methodological
      errors (experimental error), such as those related to the placement of markers (task carried
      out by an evaluator, usually a Therapist, or with the processing of a video made by the
      operator of the software. The consistency or repeatability of the measurements is what is
      known as reliability. In other words, reliability is a measure of the variability that exists
      between repeated measurements, and is usually estimated, as recommended, using the intraclass
      correlation coefficient "ICC" (Relative Reliability) and the standard error of the measure
      "SEM" (Absolute Reliability). Its determination is very important, since in daily practice it
      could give information on whether the observed change in a certain parameter of the gait is
      due to the intervention / evolution of the pathology or to the variability of the
      measurements. In the context of gait analysis, reliability is typically evaluated
      "inter-pass" (between several passes of the same subject, in the same session),
      "intra-operator" (same video evaluated by the same operator at two different times),
      "interoperator" (same video, different operators), "intra-evaluator" (same evaluator,
      different sessions) and "inter-evaluator" (same session, different evaluators). To the best
      of our knowledge, the reliability of SILEMA has not been reported, being the objective of the
      present study, to determine this metric, with the intention of expanding its use, both for
      the clinic and for research.
    

Intervention name(s): SILEMA
Intervention type(s): Diagnostic Test
Intervention description(s): SILEMA consists of a webcam connected to a laptop, a LED reflector, and a software. To carry out gait analysis with SILEMA, an Evaluator must place six yellow auto-adhesive markers over certain anatomical landmarks in the lower limbs, namely, greater trochanter, external femoral condyle, head of the fibula, lateral malleolus and base and head of the fifth metatarsal. The patient is asked to walk barefoot through an eight meter walkway at a self-selected speed, while a webcam connected to a laptop records a video. Then, an Operator, making use of the software, processes the video, obtaining spatio-temporal and joint kinematic parameters.
Observational model: Other
Time perspective: Cross-Sectional
Sampling method: Probability Sample
Study population: 
        Healthy adult volunteers
      
Keywords: Gait; Reliability; Video; Kinematics; Temporo Spatial Parameters