Visual Training Program to Improve Balance and Prevent Falls in Older Adults
Condition: Accidental Falls; Musculoskeletal Equilibrium
Study type: Interventional
Phase: Phase 1

Summary: 
      The ability to maintain balance and avoid falling is highly dependent on the ability to
      locate objects and architectural features in the environment. This need to continually
      monitor the environment as one moves about in daily life suggests a critical role for visual
      attention, gaze control, and spatial memory, all of which are known to decline with aging. In
      this study, the investigators will test the efficacy of a computer-based visual-training
      program designed to improve the ability to rapidly extract information from the peripheral
      visual field. It is expected that older adults involved in the visual training intervention
      will improve the speed, accuracy, and effectiveness of reach-to-grasp balance-recovery
      reactions evoked by sudden unpredictable balance perturbation.
    

Detailed description: 
      Balance reactions that involve rapidly stepping or reaching to grasp a handrail or other
      objects for support play a crucial role in preventing us from falling when we lose our
      balance. However, to recover balance successfully, the central nervous system has to be able
      to control the stepping or grasping movement to deal with "environmental constraints" (i.e.
      objects and architectural features that can obstruct stepping or serve as handholds to
      grasp), and hence must somehow monitor the location of potential constraints as we move about
      in our daily lives. The need to monitor these environmental features suggests a critical role
      for visual attention, gaze control, and spatial memory, all of which are known to decline
      with aging. Although no studies have examined the effects on balance control, it is known
      that such deficits can impair other motor behaviors such as driving and can be successfully
      countered using a computer-based "visual training" intervention designed to improve the
      ability to rapidly extract information from the peripheral visual field (the so-called
      "Useful Field of View", or UFOV).

      The proposed research will use an analogous approach to improve balance control.
      Specifically, we will test whether: 1) the UFOV® computer-based visual-training program or a
      commercially available video game leads to improved ability to use peripheral vision to
      monitor changes in the spatial features of the surrounding environment, and 2) whether such
      changes in visual processing are associated with improved ability to rapidly reach and grasp
      a handrail for support, in response to a sudden unpredictable balance perturbation. Older
      adults with documented deficits in UFOV scores will be randomly assigned to either the visual
      training (UFOV or video game) or a control group. Each training group will undergo two
      one-hour sessions per week, for five consecutive weeks. Neither group will be given any
      information as to which training method is expected to be more beneficial.

      Participants in the experimental group will complete either the computerized UFOV®
      speed-of-processing intervention or the video game training intervention. This UFOV
      intervention focuses on the ability to quickly identify and locate visual targets presented
      (for brief time intervals) in the central and peripheral visual fields. The training
      challenges the participant to identify the target(s) in the briefest display duration
      possible, within increasingly difficult task conditions. Difficulty of the training task is
      increased by making it more difficult to identify the central target, decreasing the duration
      of target presentation time, increasing the number of tasks to complete simultaneously,
      adding distracters, and increasing the eccentricity (visual angle) of the peripheral targets.

      Participants in the video game training group will participate in game play sessions using a
      cartoon-based action video game with increasing levels of challenge and difficulty.

      Participants in the control group will complete timed computerized word puzzles during the
      training sessions. This cognitive task involves levels of social interaction and computer use
      similar to the experimental group, but is not expected to yield improvements in ability to
      rapidly process peripheral visuospatial information.

      Balance assessments will be performed immediately before and after completion of the
      intervention programs. Balance perturbations will be delivered using a large (2x2m)
      computer-controlled motion platform. Subjects will stand at the center of the platform and a
      motor-driven moveable handhold system will be mounted to the front wall of the platform. In
      each trial, the handhold (a 10cm rod) will be controlled to move, intermittently and
      unpredictably, back and forth along a horizontal axis in the frontal plane, before coming to
      rest at one of four final locations (corresponding to visual angles of 5, 10, 15, and 20
      degrees). The moving platform will deliver a small perturbation a few seconds after the final
      handhold location is reached. Subjects will be told to grasp the handhold as quickly as
      possible in response to the platform motion. During each trial, subjects will perform a
      concurrent visual vigilance task, which requires them to continuously look straight ahead at
      the center of a computer screen. This task is designed to ensure the subjects rely on
      peripheral vision to acquire the spatial information needed to direct the hand toward the
      handhold following the onset of the platform perturbation. The absence of any eye movements
      toward the grasp location will be confirmed via recordings from a head-mounted eye tracker. A
      motion-analysis system will be used to determine the speed and accuracy of the grasping
      reactions.
    

Intervention name(s): computerized visual training; computerized word puzzles; video-game based visual training
Intervention type(s): Procedure; Procedure; Procedure
Intervention description(s): two one-hour training sessions per week, for five consecutive weeks; two one-hour sessions per week, for five consecutive weeks; two one-hour training sessions per week, for five consecutive weeks
Other intervention name(s): "Useful Field of View" (UFOV) training; "Super Text-Twist" puzzles; Video game training
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Primary purpose: Treatment
Keywords: Vision; Visual attention; Postural balance; Geriatrics