Sensory Training for Visual Motion Sickness
Condition: Dizziness; Vertigo; Motion Sickness
MeSH terms: Vertigo; Dizziness; Motion Sickness
Study type: Interventional

Summary: 
      This is a preliminary study to determine the reliability and validity of new tests of
      orientation and balance, as well as to test the effects of a new treatment for visually
      induced dizziness. Tests involve determining vertical alignment. The treatment is task-based
      and involves focusing attention on internal body sensations to help improve the sense of
      upright. Testing is done twice before and twice after treatment, which is provided
      twice-weekly during a three-week period between testing. The total time participants are
      involved in the study is approximately six weeks.
    

Detailed description: 
      Falls are a major concern for people living in countries all over the world. Tens of millions
      of people who fall are seriously injured and hundreds of thousands of people who fall die
      every year. People who are dizzy are far more likely to fall. The investigators are
      particularly interested in working with people who have dizziness that is caused by watching
      motion or looking at complex patterns (e.g. checkerboard patterns, walking through grocery
      store aisles, riding in vehicles, or watching movies).

      This type of dizziness or vertigo is typically described as motion sickness or, more
      specifically, visually-induced dizziness. This problem affects adults who are healthy and
      adults who have a variety of health conditions. No diagnostic tests for this condition exist
      at this time and the treatments currently being used may result in worsening dizziness for
      some patients.

      New tests were created for orientation and balance, as well as a new treatment for
      visually-induced dizziness. This is a preliminary study of the reliability and validity of
      the tests we developed, as well as whether the new treatment created results in reduced
      dizziness, improved balance, and changes in daily functioning.

      It is not known whether the new tests of orientation and balance are better, worse, or the
      same as existing tests in the ability to detect problems, nor is it known if the new
      treatment technique is any better, worse, or the same as existing treatments for dizziness
      and imbalance. It is hypothesized that the new tests will be accurate and able to detect
      problems in impaired adults. Additionally, that the treatment will result in less dizziness,
      better balance, and reduced risk of falling.

      The plan is to enroll a total of 30 people in this study, 15 who are healthy and 15 who have
      visually-induced dizziness due to a vestibular (inner ear) problem. Each participant will
      complete several questionnaires and tests of balance performance before and after undergoing
      the treatment. Participants attend 8 visits over 6 weeks. Each study visit lasts
      approximately 60 minutes.

      During visits 1 and 2, which is a double baseline phase, the reliability and validity of the
      new testing procedures will be assessed. All participants will then enter the treatment phase
      (visits 2 through 7) and will attend twice-weekly appointments for three consecutive weeks.
      Following the treatment phase, participants will be re-assessed twice, immediately after
      (visit 7) and one week after (visit 8) completing treatment. During this phase, the
      short-term effectiveness of the treatment will be assessed.

      Participants will complete questionnaires that measure the intensity of visually-induced
      dizziness, perceived handicap due to dizziness, and the impact of dizziness on daily
      functioning. Performance measures include the ability to determine what is upright based on
      the internal sense of gravity (verticality), standing upright, and walking-related balance
      tasks. The verticality tests are performed while the participant is secured in a harness and
      are either standing upright or tilted to the left or to the right. The testing task is to
      determine upright based on using internal body sensations. The standing balance test is
      performed on a platform that measures balance. The verticality tests and the standing balance
      test are experimental.

      The treatment is task-based and is performed while the participant is supported in a harness
      and wearing virtual reality goggles. During the treatment, participants are either standing
      upright or tilted to the left or to the right. The treatment involves focusing attention on
      internal body sensations to help determine whether an image that is presented in an otherwise
      black virtual environment is aligned with gravity. Other visual and sound cues will be
      eliminated to prevent the use of these cues from influencing decisions about what is upright.
      As the participant becomes more successful at determining what is upright, the difficulty of
      the treatment task is gradually increased.

      Participants symptoms will be monitored throughout the testing and treatment. Participants
      are given regular rest breaks and may request to rest at any time. Participation is voluntary
      and may be discontinued at any time.

      The investigators anticipate only mild and infrequent side effects related to testing and
      treatment. The results of this study may influence how orientation and balance are assessed
      and how visually-induced dizziness is treated.
    

Intervention name(s): Sensory re-weighting
Intervention type(s): Behavioral
Intervention description(s): During training, sensory re-weighting is driven by priming upregulation of somatosensory cues. Two rounds of training, each lasting 15 minutes and block-randomized in sets of 10 trials, are conducted per training visit. In each training trial, participants must determine the direction of gravity and then indicate if the rod being displayed is aligned with gravity or if it needs to rotate clockwise or counterclockwise for that to be so. Participants will be instructed to pay attention to what they feel from their feet, legs, and gut during training and to use that pressure, stretch, movement, and muscle tension feedback to help them sense gravity. Immediate auditory and non-orienting, visual feedback is provided after each trial. A staircase method is used to adapt the level of difficulty based on response accuracy. After two consecutive correct responses, the difficulty increases. After each incorrect response, the difficulty decreases. This process is repeated in each round.
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Intervention model description: The study will be conducted in three phases. The first phase is for baseline testing. The second phase is when treatment occurs. The third phase is for follow up testing. Participants will be tested twice during the baseline and follow up phases. Six treatment sessions will occur during the treatment phase.
Masking: None (Open Label)
Primary purpose: Treatment
Keywords: verticality; postural balance; visual dependence