Postural Control During Walking and Standing Among Children With Autism Spectrum Disorder
Condition: Autism Spectrum Disorder
MeSH terms: Autistic Disorder; Autism Spectrum Disorder; Child Development Disorders, Pervasive
Study type: Observational

Summary: 
      Lately, many researchers have found that Children with autism spectrum disorder (ASD) are
      most likely to have gross motor deficiencies such as lack of coordination in gait and
      balance. Much has been researched on etiology and motor learning, but only very few
      researches have examined and analyzed quantitatively gait and balance in ASD. The aim of this
      research is to analyze quantitatively balance, gait and balance during perturbation in
      children with ASD and to compare with typically developed children (TD). A group of 20
      children diagnosed with ASD and a control group of 20 TD children will be recruited and
      tested in the laboratory with well-established measures of gait and balance function. They
      will be instructed to stand as still as possible on a force plate with different task
      conditions : (1) standing with the eyes open (EO) - standing upright viewing an "X" displayed
      on a screen 3 meters in front of them; (2) eyes closed (EC) - same as (1) with the eyes
      closed and covered by blindfolds (i.e. no visual information). (3) Same as 1 standing on foam
      (i.e., conflicting proprioceptive information). Gait will be measured using the narrow base
      walk test, modified for clinical use. Participants will be asked to walk within a narrow path
      6 meters long . The statistical analysis will include Independent T-tests to compare the ASD
      and controls with respect to different characteristics. General Linear Model (GLM) will be
      used by applying a separate model where the dependent variables will be the average values of
      the postural stability or gait stability parameters (continuous) and the independent
      variables were categorical by the group and task condition.
    

Detailed description: 
      Study protocol The study group will be consisted of 30 ASD children (6-12 years old) who were
      diagnosed with ASD recruited in the Pediatric Neurology clinic at Soroka Medical Center,
      Beer-Sheva, Israel, and ASD centers. A convenience sample of 30 age-gender matched healthy
      control children (6-12 years old) will be recruited using ads and flayer in Beer-Sheva and
      area. Children's parents will sign the informed consent, in accordance with procedures
      approved by the Helsinki Ethics Committee in Soroka Medical Center. As part of the initial
      assessment all children including the control group subjects will undergo a complete
      neuro-developmental and motor screening evaluation by an experienced pediatric neurologist
      using the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) diagnostic criteria
      Children with autism have to meet Diagnostic and Statistical Manual of Mental Disorders,
      Fourth Edition (DSM-IV) criteria. ASD participants will have to communicate enough in order
      to cooperate and understand orders. Exclusion criteria are: ASD children who were diagnosed
      with neurological, orthopedic, or psychiatric diagnoses according to DSM-IV criteria that can
      affect motor control and postural stability; cerebral palsy; neuropathic diseases; limb
      fracture; head trauma during the previous year; use of any medication other than MPH during
      the study period; and who had an IQ score below the normal range (<70), as assessed by the
      Wechsler Intelligence Scale for Children - Revised (Wisc-R) administered by a child
      psychologist.

      Recruitment procedure ASD participants will be recruited in the children neurology department
      at Soroka Medical center. Control group subjects will be recruited from the community using
      personal contacts using ads and flayer. The PI of this project (Prof. Zamir) will not be
      involved in the recruitment procedure of the children's under his clinical practice.

      Outcome Assessments: Postural stability Protocol The assessment procedure will be made in the
      ediatric Neurology clinic at Soroka Medical Center, Beer-Sheva, the parents will sign of the
      informed consent than the participant will be instructed to stand upright as still as
      possible on the force platform with the feet positioned as close as possible (heels and toes
      touching). A total of five 30-second quiet-standing trials will be obtained from each
      participant instructed to stand as still as they possibly can in two task conditions. Two
      minute rest break will be provided between two task conditions and thirty seconds rest breaks
      between the trials. The two task conditions are: (1) standing with the eyes open (EO) -
      standing upright viewing an "X" displayed on a screen 3 meters in front of them; (2) eyes
      closed (EC) - same as (1) with the eyes closed and covered by blindfolds (i.e. no visual
      information). (3) Same as 1 standing on foam (i.e., conflicting proprioceptive information).
      Balance measurements will be collected with a Kistler 9287 single force platform (Kistler
      Instrument Corp., Winterthur, Switzerland) that measures the time-varying displacement of the
      Center of pressure (CoP). The force platform data will be sampled at a frequency of 100 Hz
      and stored on a hard disk for later processing. Four well-established parameters of postural
      stability will be extracted using automatic code written in Matlab (Math Works Inc.,
      Cambridge, MA, USA): 1) Mediolateral CoP range (mm) (ML-sway Range); 2) Anterioposterior CoP
      range (mm) (AP-sway Range); 3) Mean velocity of CoP sway (mm/sec); 4) Sway area (mm2) - the
      elliptical area of the CoP points. Lower postural stability scores indicate higher levels of
      postural control. Also four parameters of SDA were extracted using automatic code written in
      Matlab: 1) short-term diffusion coefficients in mm2s-1 (Drs); 2) long-term diffusion
      coefficients in mm2s-1 (Drl); 3) the Critical Time in sec (Ctr); and 4) Critical Displacement
      in cm (Cdr). These parameters will be computed for each subject's trials, and then averaged
      for each set of 5 trials to obtain an average value for each parameter and for each subject,
      in each experimental condition.

      Gait stability protocol After a 10-minute break, gait will be measured using the narrow base
      walk test, modified for clinical use. Participants will be asked to walk within a narrow path
      (6 meters long) first without and then with a concurrent cognitive task (ST- and DT), always
      in the same order. The test incorporates measurement of lateral instability during gait. The
      width of the narrow path will be normalized to 50% of the distance between the participant's
      anterior superior iliac spines + the width of the subject's shoe. This produces a similar
      challenge for individuals with different body morphologies. The narrow path will be outlined
      by two narrow six meter black mattresses on the walking surface; the participants will be
      instructed to walk within the path without stepping on the black mattresses. All trials will
      be videotaped using a video-camera that was placed 2 meters in front of the walking path and
      1.5 meters high to detect trial time and step errors during the test. Step error is defined
      as every step where the subject's shoes step outside the narrow path, touching the black
      mattresses outlining the sides of the narrow base walkway. test-re-test agreement of NBWT
      found to be high for all variables; ICC(1,2) 0.77-0.92 in ST and 0.78-0.92 in DT (unpublished
      data).
    

Intervention name(s): no intervention required
Intervention type(s): Other
Intervention description(s): no intervention required
Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        children with autism spectrum disorder
      
Keywords: Postural control; Gait; Children; Autism Spectrum Disorder