Fitts Law in People With Cerebral Palsy

Evaluation of Speed-accuracy Trade-off in a Computer Task in Individuals With Cerebral Palsy

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.

Study Overview

• Status: Completed
• Conditions: Cerebral Palsy
• Intervention / Treatment: Behavioral: Cerebral Palsy group; Behavioral: Control group

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.

• Study Type: Interventional
• Enrollment (Actual): 96
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 7 years to 30 years (Child, Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• medical diagnosis of CP;
• levels I to IV according to the GMFCS;
• levels I to III according to MACS.

Exclusion Criteria:

• presence of surgery or a chemical neuromuscular blockade in the upper limbs within six months prior to participation in the study;
• lack of comprehension of the experimental instructions.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Non-Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cerebral Palsy group; Group with Cerebral Palsy that performed the Fitts law in a computer task	Behavioral: Cerebral Palsy group; Group with Cerebral Palsy that performed the Fitts law in a computer task
Active Comparator: Control group; Group with typical development that performed the Fitts law in a computer task	Behavioral: Control group; Group with typical development that performed the Fitts law in a computer task

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Time Frame
Motor control test by using a fitts law task in computational task	one day

Collaborators and Investigators

• Sponsor: University of Sao Paulo
• Investigators: Principal Investigator: Carlos BM Monteiro, Ph.D., University of São Paulo

Publications and helpful links

General Publications

• Fernani DCGL, Prado MTA, da Silva TD, Massetti T, de Abreu LC, Magalhaes FH, Dawes H, de Mello Monteiro CB. Evaluation of speed-accuracy trade-off in a computer task in individuals with cerebral palsy: a cross-sectional study. BMC Neurol. 2017 Jul 27;17(1):143. doi: 10.1186/s12883-017-0920-4.

Study record dates

Study Major Dates

• Study Start: January 1, 2016
• Primary Completion (Actual): August 1, 2016
• Study Completion (Actual): November 1, 2016

Study Registration Dates

• First Submitted: December 19, 2016
• First Submitted That Met QC Criteria: December 20, 2016
• First Posted (Estimate): December 23, 2016

Study Record Updates

• Last Update Posted (Estimate): December 23, 2016
• Last Update Submitted That Met QC Criteria: December 20, 2016
• Last Verified: December 1, 2016

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Brain Damage, Chronic; Cerebral Palsy
• Other Study ID Numbers: 14652713.9.0000.0082

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED