Fitts Law in People With Cerebral Palsy
Condition: Cerebral Palsy
MeSH terms: Cerebral Palsy
Study type: Interventional

Summary: 
      Introduction: Cerebral palsy (CP) is a non-progressive disorder in the brain which makes the
      control and execution of movements difficult. One of the possible ways to analyze motor
      control in these individuals could be through analysis of movement speed and accuracy.
      Objective: To verify the speed-accuracy trade-off in individuals with CP. Method: 96
      individuals were evaluated, 48 with CP and 48 with typical development (TD), matched by age
      and sex. The software used was the "Fitts' Reciprocal Aiming Task v.1.0 (Horizontal)",
      performed on a computer using an external optical mouse, with progressive indices of
      difficulty (IDs): ID2, ID4a and ID4b. Each index of difficulty was performed three times and
      the total time/touches captured.
    

Detailed description: 
      The software used in this study was "Fitts' Reciprocal Aiming Task v.1.0 (Horizontal)"
      developed by Okazaki, in the public domain and available on the Internet, which was performed
      on a Toshiba notebook®, model Satellite A60-S1561 System Unit, with the use of an external
      optical mouse, Fortrek® OM-302.

      This instrument can be used to verify motor control through analysis of the speed and
      accuracy of movement, which can be determined through the log-linear relation between
      movement time and task difficulty using a mathematical equation, and analyzed by Fitts' law,
      which describes the relation between movement accuracy and speed, associated with target size
      and distance11. Thus, the task used in this study was composed of targets of different sizes,
      being that the smaller targets require more time to execute due to the necessity of increased
      accuracy and, if the distance between targets reduces, the speed of movement becomes greater
      and the accuracy decreases.

      In relation to target size (W) and distance between targets (D), the equation log2 (2D/W)
      results in an index of difficulty (ID), where the higher the ID, the more difficult the task,
      a fact that necessitates greater movement time.

      To evaluate the speed and accuracy, two different indices of difficulty were used in this
      study (ID2 and ID4). The difficulty level was increased by changing the width and distance
      between the bars. In addition, ID4 was used in two different ways (ID4a and ID4b), for which
      the distance between the bars and the width were different, but the ID was maintained.

      3 Procedure and design The experiment was composed of three trials at each of the two IDs: 2
      and 4 (ID 4 had two kinds of measurement - ID4a and ID4b), and the participants performed the
      tasks individually in a room, with only the evaluator present, seated on a chair (or their
      own wheelchair), which was adjusted in height according to the needs of the individual. A
      footrest was available, when necessary. The computer was placed on a table, and each
      participant was given instructions and presented with the task, in which the individual,
      after hearing an alarm from the computer, was required to click with an external mouse cursor
      on two parallel bars which were arranged vertically, intermittently, with the greatest speed
      and accuracy possible, for a period of 10 seconds, followed by a second alarm which indicated
      the end of the attempt.

      Directly following the attempt, the total movement time was registered, by dividing the
      seconds obtained in each attempt by the number of "clicks" on targets. If more than two
      clicks were wrong, the individual repeated the task.

      Procedure and design The experiment was composed of three trials at each of the two IDs: 2
      and 4 (ID 4 had two kinds of measurement - ID4a and ID4b), and the participants performed the
      tasks individually in a room, with only the evaluator present, seated on a chair (or their
      own wheelchair), which was adjusted in height according to the needs of the individual. A
      footrest was available, when necessary. The computer was placed on a table, and each
      participant was given instructions and presented with the task, in which the individual,
      after hearing an alarm from the computer, was required to click with an external mouse cursor
      on two parallel bars which were arranged vertically, intermittently, with the greatest speed
      and accuracy possible, for a period of 10 seconds, followed by a second alarm which indicated
      the end of the attempt.

      Directly following the attempt, the total movement time was registered, by dividing the
      seconds obtained in each attempt by the number of "clicks" on targets. If more than two
      clicks were wrong, the individual repeated the task.
    

Intervention name(s): Cerebral Palsy group; Control group
Intervention type(s): Behavioral; Behavioral
Intervention description(s): Group with Cerebral Palsy that performed the Fitts law in a computer task; Group with typical development that performed the Fitts law in a computer task
Allocation: Non-Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment