Motor Learning

13 Motor Learning


Janet M. Howle



Motor learning (ML) results from experience and practice of motor skills in specific contexts that relate to function and participation. This chapter defines ML and differentiates between motor learning and motor performance. Neuro-Developmental Treatment (NDT) intervention provides active learning opportunities taking into account the characteristics of the typical and atypical learner, the importance of setting goals in contexts that are meaningful, and the use of hands-on guidance and verbal and nonverbal instructions to engage and support the learner.



Learning Objectives


Upon completing this chapter the reader will be able to do the following:


• Apply motor learning assumptions to NDT practice.


• Identify and differentiate between the characteristics of motor learning and motor performance.


• Analyze the importance of various principles of motor learning as they relate to NDT practice and International Classification of Functioning, Disability and Health (ICF) domains, including


image preparation of effective motor learning experience;


image task characteristics;


image instructions for motor learning;


image importance of practice—scheduling practice, intensity and frequency;


image feedback; and


image effective learning environments.


13.1 What Is Motor Learning?


Motor learning (ML) is defined as a set of processes directly related to practice or experience leading to relatively permanent changes in motor skills.1 Most therapists implicitly apply ML principles during intervention for both adults and children who have impairments in posture and movement, including identifying the value of the task, designing active transfer-oriented practice, providing feedback, relating learning to the stage of development or recovery, and focusing on the importance of the environmental context.2,3,4,5,6 Neuro-Developmental Treatment (NDT) practice accepts that ML results from the dynamic interaction of all the body systems needed to carry out a specific task in a meaningful context. Each system (neuromotor, musculoskeletal, sensory, regulatory, etc.) is necessary, but not sufficient, to drive change in motor function. ML strategies are fundamental in planning NDT intervention programs and include informational and motivational characteristics to enhance generalization and transfer learning of motor skills beyond intervention.


Over the past decades, ML theories that hypothesize how motor skills are acquired through practice or experience have evolved, and parallel changes have taken place in the incorporation of ML principles in NDT, moving from the therapist determining the patient’s functional limitations and directing intervention to recognizing the importance of self-determination in goal setting to ensure carryover of functional changes into participation in everyday life. Early on in NDT practice, the client was a more passive recipient of structured, well-controlled intervention that stressed changes in motor performance (MP) rather than ML. Although the Bobaths7 included age-appropriate tasks and environmental considerations in their early writings, the focus on their methods that changed the quality of movement overshadowed these aspects of their intervention approach. As dynamic theories on learning emerged, NDT therapists increased their attention to the importance of verbal and nonverbal feedback, task-specific training, practice variability, and meaningful context.


Practice of motor skills, when conducted in a meaningful context, has been shown to reduce the gap between intervention and function and provides a clear link between therapy and daily living.8,9 Our understanding of the importance of practice and its context has significantly changed and enhances our ability to help our clients achieve carryover from therapy to life.


ML principles are currently integrated into both examination and intervention and are accepted as part of the NDT Practice Model that is described earlier in this text. Assumptions in ML listed below, along with those of motor control and motor development, help therapists organize and plan NDT intervention.


13.1.1 Neuro-Developmental Treatment Assumptions in Motor Learning


• ML results from experience and practice of motor skills in specific contexts that directly relate to function and participation.


• NDT intervention is structured to provide active learning opportunities in an appropriately stimulating and supportive environment.


• Based on an understanding of plasticity and recovery, the effectiveness of intervention varies with stages of development and recovery.


• Variations are seen in every client’s learning level, style, and capability, and therapists expect changes in these characteristics over the life span.


• Tasks must be appropriately motivating, stimulating, achievable, and meaningful to ensure motor learning.


• Intervention is structured to evoke active participation on the part of the learner.


• NDT therapists use physical, cognitive, verbal, and nonverbal instructions and provide both verbal and nonverbal feedback at appropriate times.


• Goals and outcomes that are set in active partnership with the learner and are specific, meaningful, attainable, and of moderate difficulty have the greatest effect on ML.


• Clients develop strategies for solving motor problems, and NDT clinicians recognize that individuals are influenced by past experiences, their system competencies and limitations, motivation, priority, value, and necessity.


• Practice, with increasing degrees of challenge, is prerequisite for ML and varies with the stage of the learner.


• Errors during practice can facilitate learning. Therapists let clients make mistakes within a range or margin of error needed for learning while ensuring safety.


• Changes in motor skills occur under conditions that most closely resemble the task specificity the learner will encounter during the performance of that skill.


• Hands-on guidance is an important NDT teaching–learning strategy that if used judiciously influences ML. Therapeutic handling can be used as a practice strategy or a form of nonverbal feedback.


• An optimal state of readiness, including readiness in the attentional, physical, emotional, cognitive, and sensorimotor systems, prepares the individual for the motor action.


• Preparing a client for movement includes a supportive therapist–client relationship; a safe, comfortable environment; motivational activities; consideration of alignment and posture; and a level of challenge that matches the capabilities of the client.


• Previous experience, experimentation, memory, and recall are additional elements that enhance ML.


• Improved performance (the ability to perform better immediately following practice) does not automatically equal ML (the degree of long-term retention of performance capability). NDT recognizes that ML requires a transfer of skills to the daily life setting.


13.1.2 Differentiating Motor Learning from Motor Performance


ML and MP are two distinct concepts with different goals of intervention. It is important for the clinician to understand the difference between ML and MP when planning intervention to enhance ML. This chapter focuses on ML, defined as the direct result of practice or experience that influences the individual’s ability to process information and leads to relatively permanent changes in skilled actions that can be retained, transferred, or generalized.1,10 Skill is the consistent performance and attainment of an action-goal with economy of effort and is the result of organizing movement for an individual solution to a motor problem. ML is the set of underlying events, occurrences, or changes that happen when practice enables a person to become consistently skilled at some task. Research has shown that the more closely the demands in the practice environment resemble those in the actual environment the better will be the transfer of skill.11,12,13 ML can be measured either by the degree of long-term retention of performance capability or by the amount of transfer to other tasks or different settings.12,14,15


MP, on the other hand, is the change in motor behavior that comes from a variety of temporary factors during and immediately following practice.16 Improved performance does not necessarily imply that learning has occurred, and it is important to make the distinction between improved MP and increased ML. In fact, practice conditions that promote long-term retention might be different from the practice conditions that produce immediate improvement in MP. Setting up conditions for long-term retention for ML may actually decrease the quality of immediate MP. Errors during practice can facilitate learning. This implies that therapists need to be comfortable letting clients make mistakes within a range or margin of error needed for learning while ensuring safety. Therapists need to provide the client with opportunities to correct their own errors without immediately providing corrective feedback.14,15


13.1.3 Planning an Effective Motor Learning Experience Task Requirements


Effective ML requires tasks that are goal directed, meaningful, attainable, and of moderate difficulty for the learner.17,18 Selection and sequencing tasks in an ML framework take into account the characteristics of the learner, including age, body system integrities and impairments, functional abilities and limitations, social participation and participation restrictions, as well as environmental contexts. Tasks that are self-initiated, self-controlled, and require active participation of the learner are the most satisfying and therefore of great importance for ML. Client-centered goal setting is often discussed as a key to successful ML. Missiuna and Pollock19 reported that children as young as 5 are able to set goals and priorities for occupational therapy and could identify which tasks were most difficult for them; however, therapists do not always include client-centered goal setting. Even with adults poststroke, studies show that therapists often do not include client-centered goal setting as a consistent part of their practice in rehabilitation settings.20,21


Preparation

Preparation for an ML experience involves addressing the overall context that is conducive to the individual’s learning ability and style. Children and adults respond positively to a multicontext approach that requires the individual to apply the newly learned skill to multiple situations.22 Providing real contexts for practice leads to ML under a variety of conditions. For example, children with cerebral palsy (CP) demonstrated better quality of movement when reaching for a doll while playing a game when compared with reaching without an age-appropriate purpose.23 In contrast, Higgins and Spaeth24 showed that the narrower the context, the narrower the solution and the more consistent, or stereotyped, the movement.


Movement is the means by which individuals solve motor problems and includes cortical and subcortical awareness of the kinematics of the movement as well as the external and internal forces needed to exactly match the features of the movement with the task. In addition, the structure of the movement can be consistent (stereotypic) or variable (nonstereotypical), depending on the problem and the context.


Understanding movement characteristics can increase effectiveness in planning sessions for learning tasks. Changing movement characteristics, such as fluency, variability, originality, flexibility, and elaboration on movement patterns, leads to an increase in problem-solving capacity and ML. Individuals who solve similar movement problems using several different organizational strategies are more likely to develop permanent changes in motor skills and a wider range of strategies that they can use for future movements under a variety of conditions.8


Goal setting and instructions before practice are part of ML preparation. The pretask period is important for information processing, decision making, and response programming.25 Various investigators found positive effects on MP and ML when the learner selected specific movement goals of moderate difficulty, contrasted with the results when the instructor selected easy or vaguely stated movement goals.26,27,28 Although cognitive understanding of instruction makes ML faster, ML can still occur when a learner is limited in the ability to process instructions, such as clients with Alzheimer’s disease, traumatic brain injury (TBI), or mental retardation.27 In all cases, the learner must be motivated to learn a motor task for intentional learning to occur. Larin6 described three factors in motivated learning.


1. The learner must perceive that the skill is meaningful, useful, desirable, and has personal value and implications. For example, Carol in Case Report A3 was an expert seamstress and loved to swim for exercise prior to her stroke, whereas Sam in Case Report B9 is a 6-year-old boy who loved music, singing, and books. In both cases, the therapists used the clients’ interests to reach the objectives of the therapeutic intervention.


2. The learner must experience satisfaction from executing a movement. Movements that are self-initiated and self-controlled are most satisfying and therefore of great importance for ML. Children often engage in movements that seem purposeless to adults. This is particularly true of newly learned movement in which the child engages in the activity over and over. Adults usually refer to this as play or practice, but these variations are functional behaviors representing important components of ML and serve to link motor and cognitive development.29 Repetition serves a variety of useful functions, such as muscle strengthening, trials of various organizational strategies, tests of postural control and balance, and learning about the reactive forces in the body produced by the contraction of prime movers.


3. The learner must find encouragement toward higher, achievable goals after task execution by feedback from significant persons, from self-monitoring, or from the pleasure of the experience. Children often participate in the “watch me” game, setting up their own program of feedback, which invariably leads the “watcher” to suggest, “Can you climb higher, run faster, or jump or swim farther?” If the watcher’s attention fades, the child will attempt to achieve more to reengage the watcher. Adults use more subtle means for encouragement from external sources and more often set up their own rewards, such as, “I will swim four laps this week, finish weeding the garden before I stop for tea, or walk my dog every night after dinner.” Wulf and colleagues30 found that MP and ML could be positively influenced if older women were given the feedback that their performance was above average when they were learning novel balance tasks. Their ability-related concerns and nervousness were reduced and resulted in more effective learning. McKay and associates31 found a similar result regarding performance under pressure when the individuals were told they were well suited to perform well on the task.


Instructions for Motor Learning

Instructions prior to the motor task are important for motivational purposes and also as feed-forward input to convey information about the task requirements.12 Instructions include a description of the task requirements, including what will occur and when, and are based on the learner’s competencies—the neuromuscular and musculoskeletal systems as well as perceptual, cognitive, and executive functions. Cognitive, behavioral, and memory impairments may interfere with the client’s ability to process and readily act on instructions. These impairments require the therapist to give the client a chance to respond to instructions without further distracting the client or providing additional instructions. The clinician may consider alternative strategies to help the client understand the task requirements, such as use of mimicking, demonstration, and mental imaging. Use of these alternate strategies does not mean ML will not occur; it might mean ML will take longer. Well-designed anticipatory instruction can enhance the individual’s selective attention, allow the learner to process the information for task completion, and foster the ability to separate task-regulatory information from nonregulatory information.32,33


Environmental features are always considered when one is developing instructions for ML. Regulatory conditions are those environmental features that the movement must accommodate to successfully reach the goal, in contrast to the background information that is irrelevant for movement organization. For example, when a key is placed in a lock, the size and weight of the key and the shape and placement of the lock (in the door or car) are regulatory conditions that directly affect the organization of the movement. The presence of other persons in the environment, sounds in the background, or color of the key are irrelevant to the movement features and therefore are nonregulatory, although they may be factors that influence the performance of a task.


Instructions can (1) be verbal or nonverbal (demonstration, modeling, or mimicking), (2) include implicit information about the general action (“See if you can do this,” then demonstrating and modeling the task, e.g., reaching for a cup) and/or explicit information about the movement goal (“Keep your shoulder down, straighten your elbow, reach your hand toward the cup, and pick it up”), and (3) include a way to recognize goal attainment (“Once you have reached the cup, see if your elbow is straight”). Most therapists agree that the practice of functional, relevant goals elicits faster and smoother movements than nonfunctional goals. However, Boyd and Winstein34 found that when explicit factual knowledge about the task and sequence was provided prior to practice, participants with middle cerebral artery stroke did not demonstrate better motor sequences, suggesting that explicit information may be more useful to focus the learner’s attention than providing information about the task. The ability of children to benefit from explicit information may differ. Instructions to children may need to be more concrete, depending on the child’s age and abilities.35


13.1.4 How Do These Concepts of Motor Learning Impact NDT Practice?


Prior to either examination or planning intervention, the NDT therapist considers various ML assumptions. First, the therapist recognizes variation in every client’s learning level, style, capability, and motivation, and therefore plans flexibility into the approach for a given client. Second, the therapist structures a supportive environment, and as much as possible, provides real context, tools, or toys to enhance learning. Third, the therapist includes the client in setting goals that are of value to the client. This is often a difficult step because it means therapists may have to put aside their own values and priorities and focus on what the client feels are important priorities. This does not mean that the client is expected to set goals independently—in many cases the therapist may need to guide the client to set subgoals or alter expectations so that the goals are realistic and achievable, yet satisfying. Finally therapists will try out various instructional strategies to see which ones match the client’s abilities, attention, and motivation.


13.1.5 Practice in Motor Learning


Practice is often considered the most important condition for ML.1 The number of possible solutions for any one task far exceeds the number of solutions that are used. Learners reduce the scope of possibilities through experimentation and repetitions in practice. Practice should promote relevant, functional, purposeful tasks and use strategies that match the readiness of the learner to respond to the difficulty of the task.36 Practice has different effects depending on the stage of learning. During the early learning phase of a task, practice allows the learner to select among many possibilities, a reasonable, effective approach to goal attainment.1 During the early learning phase of a novel task, the learner’s variability is necessary and allows the learner to respond to changes in the environment and to respond differently depending on the situation. Once the learner has determined an effective way to perform a task, practice allows the learner to concentrate on skilled performance that includes expedient solutions characterized by economy of effort and successful action. A healthy individual maintains variable solutions that can be produced under changing task demands. Ultimately, variability establishes an organizational framework for the behavior. During this period, the individual learns which environmental conditions are regulatory, plans the initial movement patterns, and attends to feedback for organizing subsequent attempts.


Verbal guidance, observation, and attention all appear to be important for adults in the early learning phase.12 This phase of ML is cognitive with increased variability in performance and errors as the learner uses active problem solving with a high level of attention to the task goal and informational feedback. In later learning, practice changes the processing of information and organization of movement. The learner becomes more proficient in coping with task constraints. Movements become more efficient with refinement of control processes, so that movement is consistent and smooth. This phase is considered automatic because there appears to be minimal attention cost, freeing the learner from thinking about movement production so that the learner can multitask, simultaneously attending to other inputs, people, or events going on in the environment, integrating information, and planning strategies for future movement sequences.1


These differences in early and late learning might not be applicable in young children. Adolph et al37 showed that the first movement strategies selected for a risky task, such as descending a steep slope, are goal directed but can be highly inefficient and do not take into account environmental cues. Children who had practiced descending slopes as crawlers tried to descend upright when they had learned to stand, even when it was not safe. They were no more proficient at the task than those children who had no previous experience with the slope. They did not recognize which conditions of the environment were regulatory or did not understand their own motor abilities. Children must relearn control in each position, and prior experience with the environmental conditions does not help. During development, children appear to try out a variety of movement strategies that happen to occur to them, perhaps accidentally, before attending to the details of the environment, the forces, the timing required, and the consequences of their actions in selecting the safest and most economical one for the task at hand.38,39


Practice can take place in blocked, serial, or random sequences . Blocked sequencing refers to practice in a drill-type repetition, during which the individual completes all trials of a given task before undertaking another task. The more complex the skill is, the longer blocked practice may be beneficial. In the early-learning stage, blocked practice is slightly more effective than random practice in acquisition of performance, that is, until some semblance of at least part of the motor behavior is established.


Random practice refers to a mixed repetition of various tasks and has proven more beneficial than a blocked sequence when measured on retention tests because it involves repeated problem solving. Random sequencing requires a greater number of trials, and performance can actually deteriorate during the practice sessions.1 Wulf and Shea40 reviewed studies with children and found that random practice was less effective for learning complex skills because of the demand for attention, memory, and motor sequences. They found blocked practice to be more effective in this population.


Physical practice is essential to ML; however, mental practice or motor imagery is also a useful strategy for ML.41 Mental imagery is imagining the correct performance of a motor task without any associated overt movement. Individuals can use this strategy pretask, posttask, or between physical trials to enhance performance and learning. There is abundant evidence for the positive effects of motor imagery practice on MP and learning in adults with stroke. In separate reviews, both Malouin and colleagues41 and García Carrasco and Aboitiz Cantalapiedra42 found that the greatest improvements occurred with interventions that combined physical and mental practice. Specifically, investigators showed changes in gait parameters and upper extremity functions.43,44 Studies of typically developing school-aged children described the benefits of visual imagery combined with physical practice.45 Based on the results of studies with adults with stroke, motor imagery as a method to enhance ML for children with CP is being investigated.46 Mental imagery for children sparks interest and motivation and can potentially lead to spontaneous repetition of movement sequences.


Recently, NDT therapists have included the use of popular Nintendo Wii and Wii Fit video games, an intriguing method that combines elements of physical and imagery practice. Video games that provide a consistent repetition of a realistic task are being used with both children and adults with neuromuscular impairments. Various studies have looked at changes in attention, motivation, energy expenditure, balance, bimanual dexterity, postural stability, and use of the upper extremity.47,48 Berg and colleagues49 reported on a case study involving a 12-year-old child with Down syndrome who self-selected video games over an 8-week intervention period. They reported positive changes in postural stability, manual dexterity, upper-limb coordination, balance, and agility. The literature suggests that video games that require physical activity along with virtual imagery are an enjoyable and valuable means of facilitating changes; however, the level of effectiveness is still inconclusive at this time.50


Physical or verbal guidance while practicing can be an effective method for limiting excessive movement errors during the performance of a task and assists the learner through the postural adjustments and movements needed for task completion. Continuous guidance has been shown to have a positive effect on performance during trials of the practiced task but not on learning. In particular, continuous physical guidance can modify the feel of the task, reducing its specificity and transfer potential.51,52 Trial-and-error or “discovery” procedures result in effective retention and transfer performance. If the therapist includes guidance as a method of instruction, more effective learning will occur if there is an alternation between trial and error, independent movements, and guided movements, all while allowing the person to be as independent as possible and to make mistakes within the margin of error and safety, minimizing fear.1


NDT intervention includes physical guidance.53 The current view is that physical guidance or handling, used judiciously, is an appropriate strategy for enhancing both MP and ML. Some writers have expressed concern that physical guidance or handling in NDT intervention might direct attention away from the appropriate sensory cues, encourage dependence on the therapist’s cues, and possibly interfere with the client’s ability to learn actions independently.52 However, Harbourne et al54 found that infants in a perceptual-motor intervention group who received movement guided by a skilled therapist showed greater variability and exploratory behavior in sitting, whereas those in the home program group actually decreased variability. In various studies with typically developing infants and their mothers, the mothers’ handling enhanced balance, locomotion, grasping skills, and differences in gaze and affect.53,54,55,56,57,58 NDT views physical guidance as a way to permit clients to allocate their attention to the component of performance that will lead to ML when they are engaged in multiple activities.


How Are the Principles of Practice Used in NDT?

NDT intervention is an opportunity for practice of newly emerging motor skills under the guidance of a trained therapist. Therapists have the opportunity to help clients find the best solutions for their level of learning, development, or recovery. Therapists need to keep in mind the differences in practice during the early stage of learning (or relearning) a function versus those principles of practice that accompany later learning. For example, a therapist may use the strategy of partial body-weight-bearing (PBWB) treadmill training with a young child who is just beginning to step or who is recovering stepping following selective dorsal rhizotomy (SDR) surgery, as seen in (Fig. 13.1).


According to the ML research on early learning, the therapist first lets the child experiment with stepping while supported in a harness. Later, once a reasonable stepping pattern is established, the therapist guides the child to achieve a longer stride, an even step-stance rhythm, and a heel–toe sequence, along with walking overground, to move the child from stepping toward fully weighted functional walking, as seen in (Fig. 13.2).


PBWB gait training is an example of blocked practice, using drill-type repetition during which the child completes all trials before undertaking another task (see the beginning of the Practice in Motor Learning section). In this setting, a trial lasts until the child’s “best pattern” deteriorates. The rest period requires only stopping the treadmill and allowing the child to stand in the harness before the next trial begins.


13.1.6 Scheduling Practice


Scheduling practice trials is an element of ML that influences both performance and learning. Distributed practice describes a model in which the amount of rest or breaks between practice trials equals or exceeds the amount of time of the trial. This model, the most commonly used by pediatric physical therapists, has the greatest effect on learning continuous tasks and leads to better retention and transfer.59,60 Studies using distributed practice with adults with hemiplegia have shown gains in upper extremity and hand functions.61,62


Distributed practice has a positive learning effect on continuous or complex tasks because tasks of this nature require greater energy expenditures, and rest periods become increasingly important. Scheduling practice and breaks is important in ML because continuous practice can cause muscle fatigue. In children with CP or adults with neuromuscular impairments, significant fatigue resulting from repetition of activities is correlated with a lower rate of progress toward certain motor activities and can put the individual at risk for injury.63,64 The NDT therapist attempts to achieve the right amount of challenge—one that is motivating and difficult, yet achievable. Practice needs to be somewhat effortful for learning to occur, but also needs to involve effort without causing fatigue.


Jul 16, 2016 | Posted by in NEUROSURGERY | Comments Off on Motor Learning
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