2 Neuro-Developmental Treatment Practice Theory Assumptions and Principles: An Overview This chapter begins with a brief explanation of the clinical importance of theories, assumptions, and principles of intervention to guide and aid in decision making within the Neuro-Developmental treatment (NDT) framework. Three categories of questions are presented to organize the development of a theoretical foundation for NDT practice. The chapter then presents an introductory synopsis of the core theoretical assumptions within NDT practice. Related clinical principles for examination, evaluation, and intervention follow each group of assumptions. Each element will be expanded, explained, and demonstrated in later chapters of the text. Learning Objectives By the end of this chapter the reader will be able to do the following: • Define and apply to the clinical practice of NDT the terms hypothesis, theory, assumptions, and intervention principles. • Describe three core questions that organize the NDT theory, assumptions, and principles. • Describe basic assumptions that comprise the NDT Practice Theory. • Identify core principles of NDT intervention that are based on the NDT assumptions. As a therapist formulates a plan of care (POC) for an individual who is beginning intervention, an immediate decision must be made as to what to do first. What are the important issues that should be addressed? What can be safely ignored? How should the session be organized? A recommended avenue for answering these clinical questions is for the clinician to review the evidence. What evidence is available to help the therapist who is to evaluate or manage a client who has had a stroke or a child with cerebral palsy (CP)? How easy is it to access the source? What do experts in the field recommend? What is the clinician’s previous experience? And, what should the therapist do if there is limited evidence to guide decision making? What if the issues being addressed are very complex or very unique? At this point the therapist begins a clinical problem-solving process based on combining any evidence that is available, observing the individual, and gathering information concerning the family goals. The therapist needs to develop a set of clinical hypotheses to guide the intervention process. A hypothesis is “a tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation.”1 Hypotheses can help to direct both assessment and intervention. One example of framing clinical hypotheses in physical therapy is the Hypothesis-Oriented Algorithm for Clinicians (HOAC), described in the work of Rothstein and Echternach.2 The therapist who uses the NDT Practice Model to develop a plan of care (POC) could hypothesize that one person’s inability to stoop down to pick up a box (such as in Case Report A1) is primarily due to musculoskeletal impairments like decreased ROM and weakness. In another case the same activity limitation may be due to decreased somatosensory awareness on the right side. Testing the hypotheses determines the effective POC as well as the choice of intervention strategies for each client. Proceeding in this systematic way, the clinician contributes to the general knowledge base or evidence base for future practice. The ongoing formulation and testing of hypotheses are key elements in NDT practice that are uniquely applied in the individual patient’s evaluation and intervention process. A theory is a collection of hypotheses that have stood the test of time. A theory emerges when the same predictions of phenomena are consistently observed across time. More specifically, Glanz and Rimer3 define a theory as a set of interrelated concepts, definitions, and propositions that present a systematic view of events or situations by specifying relationships among variables to explain or predict the events or situations. A theory is consistent with evidence-based practice and is useful so long as it is logical, consistent with everyday observations, similar to those used in previous successful programs, and supported by research in the same area. According to Glanz and Rimer,3 a theory provides a road map for studying problems, developing appropriate interventions, and evaluating their successes. Theories can inform a planner’s thinking during all stages and offer insights to translate into better intervention. A theory can be explanatory, describing why a problem exists, or it can be a change theory, guiding the development of health interventions. Change theories can enable program planners to explain why they assume a program will work. They can help planners to identify what should be monitored during program evaluation and intervention. Within broad theories the therapist makes assumptions that guide or frame the entire evaluation, intervention planning, and implementation process. Assumptions are common and useful in day-to-day life. We assume that the sun will rise again tomorrow and that gravity will influence everyone. We assume that it is more important to consider a person’s body systems to understand the activity limitations or participation restrictions rather than assuming that the person is lazy, uncooperative, or simply in need of more practice to reach a desired outcome. Assumptions can be explicit and clearly articulated by the practitioner, or they can be implicit and not even consciously acknowledged by the therapist. Explicit assumptions can be made specific enough to be clinically tested, and, based on the findings, the overall theory can be modified. The collection of assumptions shapes the clinician’s practice. For example a clinician may begin every assessment by asking the family about the activity limitations that most restrict the individual’s participation. When asked why the examination begins in this the fashion, the clinician may or may not be able to give a theoretical explanation or articulate the assumptions on which this practice is based. However, hidden in this practice is the assumption that intervention is most effective when focused on a functional outcome that the client values. In addition, this method of examination can include the assumption that individuals learn motor tasks rather than a given component of movement. If the clinician holds these assumptions as valid, sessions would be organized around the valued functional outcomes rather than being focused solely on increasing range of motion, strengthening a muscle, or striving to improve a posture, such as developing head control. The therapist then generates principles to guide the intervention process and aid in forming a practice model. A principle is “an accepted or professed rule of action or conduct.” Principles can be general; for example, effective treatment should include active work by the client, to far more specific; for example, during intervention for a client with neuromuscular impairments, the clinician should address the patient’s inability to recruit specific postural motor units by facilitating sustained isometric contractions of the desired postural muscles in the shortened range of those muscles, as Stockmeyer suggests in Chapter 4. The NDT Practice Model then is framed by our assumptions and guided by our practice theory, and reflects the collective body of principles. The theoretical framework of NDT has emerged across time based on experience and is consistent with the philosophy described in the previous chapter. It forms a foundation for the practice model presented in Chapter 5. The NDT Practice Theory offers potential answers to broad clinical questions. The questions require that the therapist make assumptions because none of the questions have answers that are widely accepted. Assumptions central to NDT practice will be described in the following sections along with the unique clinical application of information gained from the study of motor control, motor learning, and motor development. There are three major categories of questions addressed by NDT assumptions that are foundational in the NDT Practice Model: 1. How do people function? How are the body systems organized, controlled, or coordinated in individuals without impairments? How do people typically learn to participate in or perform activities? How are functions learned at different ages, physical characteristics, in different contexts, and with different experiences? 2. What goes wrong in the control and coordination of the systems in individuals with neuromuscular disorders, such as CP, or in cases of stroke or traumatic brain injury (TBI)? 3. What is the most effective intervention for individuals with disorders of posture and movement? This final question is based on answers to the first two questions. If a clinician is working to improve a person’s ability to participate fully to or have greater or more independent functional activities, it seems reasonable that the clinician should have a theory of how posture, movement, and the working of all the individual systems lead to participation or activity. How does a person achieve a functional outcome? How do activity and participation develop across the lifespan? These questions have been explored and theories developed in the studies of motor control, motor learning, and motor development. Various answers have been proposed. The clinician determines which theories provide the most effective framework for intervention. The clinician must also expect these theories to change across time as core assumptions are tested and either accepted or rejected. The hallmark of an effective assumption is that it lasts—it stands the test of time. The remainder of this chapter explores the assumptions that frame the NDT Practice Theory and provides rationales to explain their usefulness. It then suggests the principles that will help guide effective NDT practice. How are the functions of the body systems typically organized, controlled, or coordinated to produce participation and functional activity? How do people learn to participate or perform activities? How and why do they change across the lifespan? For years scientists as well as clinicians have studied human behavior in attempts to understand how the body works to produce effective and efficient posture and movement for activity. The answers have changed based on who was attempting to answer the question and the scientific environment and theories held to be true at the time. Sherrington4,5,6 proposed one answer by suggesting that his reflexive hierarchy theory should be viewed as a “convenient”4 even if it was “probable fiction.”4 The implication is that the theory should be followed so long as it has value or benefit. For the rehabilitation therapist, the test should be, does this theory help me to solve clinical problems? and can clients who receive intervention based on this theory achieve greater functional independence than if a different theory is followed? Motor control includes information gathering and related activities performed by the central nervous system that organize the musculoskeletal system to create coordinated movements and skilled actions. The study of motor control is a large area of study and includes a wide variety of theories or assumptions. Shumway-Cook and Woolacott7 report that it encompasses both the control of posture as well as movement. It involves understanding perception and cognition, feedback processes, and biomechanics, to name a few. The NDT Practice Theory has applied assumptions from various theories of motor control to aid in designing and implementing intervention strategies. The following motor control assumptions are integral to NDT practice. Each assumption will be discussed in detail with supporting evidence provided in Chapters 4, 12, and 15. Based on an understanding of motor control, the clinician using the NDT theoretical framework and related practice model assumes the following: • Movement is organized around functional activity. • Human motor behavior/function emerges from ongoing interactions among multiple internal systems of the individual, the characteristics of the task, and the specific environmental context. • The critical systems to be addressed during examination and intervention will vary client to client, as well as vary with the same client in different environments or on different days. Posture and movement impairments may be related to a single body system, such as the neuromuscular system, or multiple body systems. • All individuals have elements on the health or wellness end of the spectrum in all of the various domains described in the International Classification of Functions (ICF)8 that is described in Chapter 3. These attributes of health and wellness in the different domains are identified as participations, activities, or integrities. • A hallmark of human motor function is the variability of posture and movement organization to meet functional demands. • The neural control for movement is distributed throughout various levels of the central nervous system (CNS), all contributing to the final motor outcome. • Plasticity in all systems exists across the lifespan. • The brain can maximize remaining functions and/or compensate for the loss of function in the event of neuropathology. • The nervous system has the ability to reorganize in response to intrinsic or extrinsic stimuli. • Plasticity is linked to brain development across the lifespan. • Intervention strategies can be designed to capitalize on the brain’s ability to modify functions based on experience and the environment. • There are anatomically and functionally distinct yet overlapping and interactive structures and function to control and coordinate posture and movement during activity. The systems can be recruited separately. Refer to Chapter 4 on posture and movement for supporting assumptions and literature. • The postural system provides the ability to maintain the upright position against gravity through vertical lift. Postural responses also maintain the center of mass (COM) over the base of support (BOS). In addition to the whole body responses, the postural system maintains the integrity of the joint structure. The term stability describes much of the goal of the postural system. • The movement system is a primary controller to overcome inertia and is also needed when a wider range and faster speed of motor responses are required. The term mobility describes the goal of the movement system. • Posture and movement represent a continuum but are organized by different descending systems. Posture is organized through the medial descending systems and movement through the lateral descending systems. • There are distinctions between motor unit types as well as muscle architecture that correlate with a postural versus a movement system. Based on these assumptions the clinician develops specific principles to guide, organize, and increase the efficiency and effectiveness of the examination, evaluation, and intervention for any given individual. These principles are presented in detail in Chapters 5, 6, 7, and 8. The particular modifications demonstrated among the different disciplines will be discussed in Chapters 16, 17, and 18. In addition, the specific application of these principles will be presented in the case reports at the end of the text. The NDT theoretical assumptions and the specific evaluation and intervention principles are best demonstrated when observed in action with each individual who seeks intervention and with each therapist offering that intervention. The following principles are based in the study of motor control and are central to NDT practice. The therapist should perform the following: • Organize the evaluation and intervention process such that participation, participation restrictions, activities, activity limitations, and the individual’s desired outcomes drive the process. • Develop specific outcomes for each session. The short-term as well as long-term POC focuses on the desired activities or participations outlined by the client. • Provide all intervention within the context of functional activities whenever possible. For example, the therapist will work to increase range of motion at the ankle joint into dorsiflexion within the context of transferring an individual to and from the wheelchair rather than performing passive range of motion while the patient is lying supine in the bed. • Plan to alter activity by addressing individual body systems or functions, by changing the environmental contexts, or by altering the task or activity itself. This principle also implies that the therapist must simultaneously consider all of these elements to understand, plan, and implement a successful intervention. • Begin the evaluation and intervention process with individualized problem solving or task analysis of the identified desired outcomes. • Perform a task analysis that takes into account all of the body systems and structures that can be the critical factors which limit or support the desired outcome. • Individualize the examination, evaluation, and intervention and vary the POC and intervention day to day, therapist to therapist, as well as client to client. This practice will include structuring an individual session differently on different days, even with the same client, as the organization of the body structures and functions changes. • Gather information from the client and the family on an ongoing basis that outlines the individual strengths as well as the limitations or impairments. • Build on these strengths or competencies within the intervention. Each session builds on the individual’s contextual facilitators, activities, and integrities. • Observe the client during examination and evaluation to determine the variability of posture and movement organizations to produce functional activity. • As soon as possible, include in intervention the introduction of variations in task performance so that the client does not develop stereotypical postures and movements to complete specific tasks. The therapist should aid the individual in developing a wide variety of muscle synergies to complete tasks, vary the tasks, and vary the environmental constraints in which the tasks are performed within the session and in providing home programs. • Identify the body systems that demonstrate the greatest limiting impact on activity performance and also those systems with the greatest potential for change in a client. In addition, the therapist looks for episodes in the individual’s lifespan indicating greater plasticity. In anticipation of or in response to these factors the therapist will alter the intensity of intervention, change the focus, or modify the specific strategies used in the intervention process. • Continually adapt the POC based on the ongoing examination and evaluation. • Use multiple sensory inputs, handling strategies, and contexts in different activities to alter the overall organization and therefore neuronal control for functional tasks. • Identify impairments of body structure and function, including multisystem postural and movement issues as well as single-system issues through observation of functional activities during examination and intervention. • Provide input through handling to specifically recruit postural or movement systems within functional tasks. In addition to striving to understand how an individual controls posture and movement for activity and participation, therapists have sought to understand the process by which people learn typical activities and participation. How do children learn to brush their teeth, walk across the yard, tell someone when they hurt or want something? How do we relearn those tasks if we have a CNS insult that leads to functional limitations? What can therapists do to promote motor learning? Do children and adults learn the same way? Do we learn the same way after a CNS insult as before one? Once again the clinician faces a large group of questions without universally accepted answers. Although there is some literature to help guide the clinician, there is once again a need to develop an NDT POC based on a list of NDT theory practice assumptions and specific principles that are derived from the study of motor learning theories. First a few definitions must be agreed upon. Schmidt9 has defined motor learning as that process or group of processes that leads to a relatively permanent change in motor behavior. Independence in performing a task is only one measure of success. A person may be able to put on a jacket independently, but if it takes 35 minutes to complete the task due to poor posture and poor coordination, the accomplishment may not be viewed as being functional or as increasing participation. Schmidt defines motor performance as the “observable attempt of an individual to produce a voluntary action. Motor performance is susceptible to fluctuations in temporary factors such as motivation, arousal, fatigue, and physical condition.”9 This definition also reflects a change that occurs based on the quality of the posture and movement during an activity or task. If an individual is learning to play tennis and for the first time hits a ball with a smooth forearm stroke that crosses the net and lands in an appropriate court, one can say that the person has an improved performance but cannot yet say that the person has learned the skill of playing tennis. Likewise, if a client in therapy sits for 10 seconds with the head and shoulder girdle held in midline over the pelvic girdle, it is not possible to state that the person has learned to sit independently for dressing. There has been a change in performance but not yet a change in activity or skill. Accomplishing the task for the first time is a success that is frequently celebrated in therapy sessions. However, before it has meaning in daily life it must be present more consistently. A skill,9 then, is the consistent attainment of a motor task with economy of effort. It reflects producing a performance with maximum certainty, minimum energy, and or a time factor. Motor learning, therefore, is a set of underlying events or changes that enables a person to become consistently skilled at some task. Because it is usually assumed that the desired outcome of therapy is a relatively permanent change in activity or participation, it is important for all therapists to consider the role of motor learning in the context of therapy sessions. It is not sufficient for a client to perform an activity in a therapy session and yet be unable to function in the home, school, or community setting. The goal of therapy is for the individual to be able to participate fully without the assistance of the therapist or the caregiver. The NDT Practice Model includes assumptions and principles of intervention that are derived from theories of motor learning. The therapist assumes the following: • Motor learning is organized around functional tasks that are valued by the individual. Tasks or functional outcomes for a therapy session that the learner selects as being meaningful and achievable are more likely to result in real motor learning. • An optimal state of readiness for motor learning in an individual includes specific personal as well as environmental contextual factors. • An optimal state of readiness for motor learning in an individual includes specific personal as well as environmental contextual factors. Motor learning can be enhanced by preparing the individual’s attentional, physical, emotional, cognitive factors, among others. We learn best when in an active alert state, but not one in which we are terrified or giddy with laughter. We learn better when the body is well positioned and well aligned for the task. We learn best if we know what we are going to learn. • Motor learning is enhanced when the learner is actively involved in the process. It is not sufficient to passively go through the activity. The level of active participation can vary according to the ability of the individual. An individual who has more severe and multiple impairments may be actively involved in a standing transfer by increasing the push with the extensors of the lower extremities and the coactivation of the muscles in the arms while supported in standing with arms resting on the therapist’s shoulders. Another individual who is more able-bodied may independently reach and hold a grab bar with an arm to complete the transfer. It is also important to know that active movement does not refer solely to consciously directed movements that are readily observable. Anticipatory postural adjustments and the compensatory postural adjustments performed as part of skilled activities can represent the individual’s active involvement in performing a new skill.10 • Motor learning is improved with accurate instruction and feedback. From an NDT perspective this includes both verbal and nonverbal instruction and feedback, including handling and physical prompting. • Handling can play an important role in motor learning, especially during the early phases of learning. • Hands-on guidance is a naturally occurring, motor-teaching strategy that influences motor learning and is particularly useful when eliciting specific behavior or when limiting the scope of error in performance aids motor learning. • Physical or verbal guidance during the task can be an effective method for limiting movement errors during the performance of a task and assists the learner through the postural adjustments and movements needed for task completion. • Learning or relearning motor skills and improving performance require both practice and experience. Motor learning results as the individual gains experience and practice in functional contexts. Repetition through practice is an important component in motor learning. Activities that are task specific and that the client repeats, both in an NDT therapeutic session and in functional ways in other settings, have a better chance of becoming part of the client’s movement repertoire. • Practicing novel skills, with increasing degrees of challenge, is important to motor learning. • Changes in motor skills occur under conditions that most closely resemble the conditions the client will normally encounter during the performance of that skill. Based on a composite of these assumptions related to motor learning, the therapist, using an NDT practice model, works to promote motor learning during intervention. The therapist should perform the following: • Identify the contextual factors (personal and environmental), including both facilitators and potential barriers, that will influence motor learning. • Establish an environment that enhances motor learning by making it comfortable, yet challenging. In addition, select activities that are intrinsically motivating for the individual. • Prepare the individual for activities and participation through optimizing the alignment and body position. • Explore the individual’s contextual facilitators during the information gathering and examination process, then tap into to these facilitators during the intervention process to increase the likelihood of success. • Organize each therapy session and each block of intervention (short-term and long-term blocks) around a desired activity. Focus each session on helping the client reach a specific desired outcome, such as eating a lunch independently or transferring in and out of the family vehicle with the caregiver’s assistance. Select outcomes that are both important to the client and a challenge to achieve. Strive to discover the just right challenge for each client. • Use specific physical, cognitive, verbal, and nonverbal instructions, and provide both verbal and non-verbal feedback. • Select instructional strategies that reflect the client’s stage of learning. Present these strategies in such a way that clients gradually select and then optimize the strategy that best matches their needs and capabilities with the task and the environment. • Incorporate handling judiciously as a strategy to enhance motor performance and motor learning. • Guide the client through the stages of motor learning while remembering that it must be an active process for the client. • Allow the client to learn from (safe) errors that occur during movement. • Provide opportunities for repetition; it is an important component in motor learning. Motor development can be defined as the body system processes underlying emergence and changes in motor skills that occur across the life span based on experience, maturation, and aging. NDT theory has always included assumptions based on the study of motor development. In the past decades the understanding of typical motor development has changed as have the implications for the rehabilitation specialist. As discussed in Chapter 1, NDT therapists recognize that general patterns exist in the acquisition of skills during typical development and maturation.11,12,13 These consistencies can provide a standard of reference for proficient human motor function for the therapist to use during examination and intervention. An analysis and understanding of these consistencies in the development of the control and coordination of posture and movement, the maturation of the individual systems, and the related changes in functional activities is used in planning intervention. The clinician using the NDT Practice Theory includes information that is based on theories of motor development and assumes the following: • Motor development is a dynamic process that occurs throughout the lifespan rather than a linear progression and then a gradual decline. • Motor development emerges from the cooperation and changes in all of the body systems, which are influenced by maturation, experience, and learning in various contexts. Motor development is not dictated by the maturation of the CNS alone. Body systems develop at different rates, enhancing or constraining the development of various motor behaviors. • Motor milestones appear as discontinuous, discrete behaviors with a definable onset, but they actually result from continuous processes involving all the developing body systems. • There is not an ideal path or sequence across the years that leads to optimal functional abilities and full participation in life activities. • Motor development is shaped by contextual factors, both personal and environmental, and the integration of all the maturing or changing body systems and functions. • NDT recognizes that parents’ normal daily handling of their infants influences motor development, as well as affecting positive parent–infant relationships. Physical guidance, as a therapeutic strategy, strives to duplicate this natural relationship between two individuals, whether adults or children. • Variability and competition among motor patterns are essential components of motor development. • Understanding typical and atypical motor patterns underlying motor function is used to recognize differences in movement in both children and adults with CNS pathology. • The study of motor development provides guidelines for creating intervention strategies that are age appropriate and facilitate variation in movement and enhance motor learning. • Directionality of development, such as cephalocaudal and proximodistal, is only a general schema; functional, skilled movement is a composite of postural stability and mobility patterns that support the observable function. The therapist is responsible for the following: • Examine each client within a life-cycle framework. • Use knowledge of motor development to respect individual differences and recognize common and typical patterns in the developmental process that prepare and enhance skill performance commensurate with age and current ability. • Use knowledge of development of posture and movement components in designing treatment strategies. • Look for prerequisites for participation in both single and multisystem integrities. The clinician studies typically developing individuals to observe what postures and movements precede specific skill acquisition. Once the clinician has developed assumptions and principles based on the understanding of how posture and movement are controlled and coordinated in normally functioning individuals, it is possible to start thinking about the second major question identified at the start of this chapter. What goes wrong in the control and coordination in individuals who have neuromuscular disorders, such as cerebral palsy (CP), or in cases of stroke or traumatic brain injury (TBI)?
2.1 Organizing Problem Solving for Clinical Practice
2.1.1 Shaping Clinical Practice through Hypothesis Generation, Theories, Assumptions, and Principles
2.2 NDT Practice Theory
2.2.1 How Do People Function?
NDT Assumptions Based on Theories of Motor Control
Principles of Information Gathering, Examination, Evaluation, and Intervention Related to Motor Control
NDT Assumptions Based on Theories of Motor Learning
Principles of Information Gathering, Examination, Evaluation, and Intervention Related to Motor Learning
NDT Assumptions Based on Theories of Motor Development
Principles of Information Gathering, Examination, Evaluation, and Intervention Related to Motor Development
2.2.2 What Goes Wrong?
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