This study contains two pilot studies: 1) one study will investigate practice dosage of a postural stepping task in healthy young individuals in order to determine an operational definition of performance plateau, and 2) the other study will investigate whether practicing beyond reaching a performance plateau improves learning of a postural stepping task in healthy older adults, compared to discontinuing practice immediately after reaching a performance plateau. The investigators hypothesize that the group that continues to practice beyond reaching their performance plateau will learn and retain the motor task better than the other group.
What is the ideal amount, or dose, of practice needed for a person to learn a motor skill? Studies suggest that "more is better," but the optimal dose of motor practice is unknown. Motor learning is defined as a set of internal processes leading to a relatively permanent change in the capability for a motor skill. Older adults and people with neurological disorders have a critical need to learn and relearn motor skills to remain independent, but standard clinical rehabilitation currently provides practice doses that are insufficient to result in motor learning. Under-dosing of practice results in sub-optimal clinical outcomes, while research studies that are dosed insufficiently to identify between-group differences are prone to misinterpretation. Therefore, it is essential for both clinical care and for research that we determine the practice dose needed to optimize motor learning. Performance curves (i.e., plots of the average performance of a group or individual for each of a number of practice trials or blocks of trials) demonstrate that performance improves (e.g., error decreases or speed increases) during practice, until a point at which performance improvement begins to plateau. Additional practice provided beyond the point at which an individual reaches a performance plateau will be termed overpractice. Amounts of practice that are insufficient to reach a plateau tend not to demonstrate motor learning, while overpractice typically results in retention of the practiced task. Pilot Study #1: The first pilot study will include healthy young adults who are randomly assigned to practice a postural stepping task for one day, or for five consecutive days of practice. The investigators will use this data to determine an operational definition (i.e., a mathematical definition) of performance plateau. This definition will be used to differentiate the groups in Pilot Study #2. Pilot Study #2: The second pilot study will include healthy older adults who will be divided into three groups: a standard of care group (i.e. very low dose), an overpractice group, and a no overpractice group. All groups will practice a postural stepping task. The experimental group will be the overpractice (OVP) group, in which each participant will complete 100% additional practice trials after reaching their performance plateau. In contrast, the two active control groups will be the no overpractice (NoOVP) group (in which each participant will stop practicing immediately after reaching a performance plateau), and the standard of care (SoC) group (in which each participant will perform one block of practice).
Subjects will perform a standing serial reaction time task on a step reaction mat. Subjects will step to a series of targets, based on a series of stimuli that are presented. One trial is composed of two 12-step sequences. One of the 12-step sequences is random, while the other is a repeated sequence; sequences are presented in random order. After each trial, the subject rests for 25 seconds. Six trials equal 1 block of practice, which is followed by a 4 minute rest break. After each block, feedback is provided about average response time (RT) on all steps included in the block. One complete day of practice consists of 6 blocks of practice in which each block consists of 6 trials.
University of Utah
Salt Lake City, Utah, United States
Retention on the Postural Stepping Task
Retention is the ability to maintain performance improvements of a motor skill after a period of no practice. Response time (RT) is collected \& defined as reaction time (amount of time from stimulus presentation to initial release of foot from electrode) plus movement time (amount of time from initial release of foot to foot reaching target). The first half of Block 1 of Day 1 serves as the pre-test performance. The primary outcome measure is the difference in the RT between pre-test and retention test. A decrease in RT over the course of practice reflects an increased response speed and a corresponding improvement in performance.
Time frame: 3 or 4 days after training ends (i.e., 2 or 3 days of no training prior to retention test)
Transfer to an Untrained Task
Transfer is the gain or the loss of proficiency on one task as a result of previous practice or experience on another task. The secondary outcome measure is improvement on the transfer task. The transfer task is the 4 Square Step Test, and is scored based on the number of seconds the participant requires to complete the test. Each participant will perform the 4 Square Step Test at baseline (pre-test) and will perform it three days after the acquisition phase ends (post-test). The post-test score will be subtracted from pre-test score, which will provide a transfer test change score. A positive number will suggest improvement, while a negative number will suggest that the participants worsened on the transfer task.
Time frame: 3 or 4 days after training ends (i.e., 2 or 3 days of no training prior to retention test)
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
SINGLE
Enrollment
65