Measuring Neurological Impairment and Functional Visual Assessment In Spinocerebellar Ataxias
Condition: Spinocerebellar Ataxia
MeSH terms: Ataxia; Cerebellar Ataxia; Spinocerebellar Ataxias; Spinocerebellar Degenerations
Study type: Observational

Summary: 
      Measuring the various difficulties patients with spinocerebellar ataxias (SCA) report in an
      accurate manner is important to be able to test any therapy that may be developed. As basic
      research identifies some therapy of this type, clinicians are planning studies that can
      either prove or disprove that such treatments actually have an effect. Walking problems and
      problems with eye movements that can give rise to visual complaints are common in the SCA's.

      Existing neurological scales such as the "SARA" are based on the usual neurological
      examination items that can carry a degree of subjective bias. Also the intervals between
      numbers on such scores often do not carry the same "weight" so that the difference between a
      score of 1 and 2 may not be equal to difference between 2 and 3. Lastly, such scales done in
      the clinic setting capture only a brief period of a patient's day. We propose that
      examination of home based gait monitoring, timed tests of motor function and quantitative
      measures of visual problems in patients with SCA are more useful in measuring the disability
      in these patients.
    

Detailed description: 
      Spinocerebellar ataxias (SCA's) are relatively rare, inherited disorders of the cerebellum
      that cause inexorably progressive imbalance and incoordination as well as speech problems.
      Recent molecular genetic studies have raised hopes for meaningful treatments for these
      conditions. Before one can embark on therapeutic studies on the SCA's it is essential that we
      have validated instruments for measuring disease progression. Rating scales based on
      neurological examinations have been reported recently but their sensitivity to change and
      reproducibility are still being examined. In an attempt to produce readily quantifiable and
      sensitive measures of motor function in the SCA's, we are proposing to examine the utility of
      home based gait monitoring, timed tests of motor function and quantitative measures of visual
      problems in patients with SCA's. These measurements which will produce continuous rather than
      categorical variables, and may be subject to less arbitrariness on the part of the examiner,
      are hypothesized to be not only valid measures but also more sensitive.

      The overall aim of the project is to assess the utility of home based gait monitoring, timed
      performance measures and functional visual testing as measures to monitor disease progression
      in SCA's. The concurrent validity of these measures will be tested by correlating them with
      an established examination based ataxia scale (Scale for assessment and rating of ataxia:
      SARA), an activity of daily living scale (Barthel index) and functional staging.

      Aim 1: Hypothesis: Motor impairment in SCA's can be assessed validly in the home setting by
      utilizing the step activity monitor (SAM).

      Aim 2: Hypothesis: Motor impairment in SCA's can be further quantified using performance
      measures: the 9-hole peg board test and the timed 25 foot walk.

      Aim 3: Hypothesis: Visual problems reported by patients with SCA's can be quantified by low
      contrast vision testing, stereoacuity measures, color vision and vergence amplitudes
      utilizing well-established ophthalmologic techniques.

      Aim 4: Hypothesis: The neurological impairment as measured by these measures will correlate
      with each other, with scores on SARA, with the Barthel index score and with functional
      staging.

      Aim 5: Hypothesis: Ataxia grading using the SAM, timed performance measures and functional
      visual scores will be more sensitive than SARA for measuring disease progression
    

Observational model: Cohort
Time perspective: Prospective
Sampling method: Non-Probability Sample
Study population: 
        Patients attending the Ataxia Clinic
      
Keywords: Spinocerebellar ataxia; Machado-Joseph disease; Gait monitoring; Functional vision assessment