T URISMO

rehabilitation training

Programs that employ task-specific training can do so for a variety of reasons. In the context of CIT, practice is designed to reverse the sub-acute conditioning that leads to decreased spontaneous use of an extremity, referred to as “learned-non-use” (Taub et al., 1994, 2003). By contrast, a training program for patients with diminished motor control and impaired func- tional ability is designed to promote skilled perform- ance (Dean and Shepherd, 1997; Sunderland and Tuke, 2005; Winstein and Prettyman, 2005).

CIT protocols grew out of the behavioral model put forth by Taub and colleagues (1994) in which it is pro- posed that during the early post-injury phase (e.g., deafferentation), use of the limb is suppressed when spontaneous attempts to move it are unsuccessful (negative reinforcement). This conditioned response is “learned” and ultimately results in diminished spontaneous use. The design of CIT protocols is there- fore directed towards the reversal of learned-non-use

and the increase of spontaneous use of the hemi- paretic limb in individuals post-stroke. Since the goal of CIT is to promote spontaneous hand use and not necessarily to develop skilled use, the condi- tions of practice are designed directly from operant- conditioning principles and include the “shaping” procedure. With shaping, a behavior is progressively modified towards the goal through successive approx- imation and positive reinforcement. In contrast to a motor-learning-based approach, the “shaping” pro- cedure as described within the context of CIT (Morris et al., 1997; Taub et al., 2003), does not address the known resource impairments of motor control, strength and coordination (Sunderland and Tuke, 2005).

Skinner (1968) taught us that shaping was a form of operant conditioning in which the probability of experimenter determined behaviors are “elicited” through reinforcement (reward or punishment). Using this procedure he shaped pigeons to peck a ping-pong ball over a net. Obviously, the pigeon is not aware that this is a game-like, goal-oriented behavior. In fact, the learner (i.e., pigeon in this case) is relatively passive in this process while perform- ance is progressively “shaped” towards the behav- ioral objective (task goal) in small steps through reinforcement or reward (positive feedback).

The shaping procedure is designed around the elicitation of behavior and not the acquisition of a voluntary skill. In fact, the pigeon, or any animal, can be shaped without knowing or ever understanding the goal behavior. The shaping procedure stands in sharp contrast to the procedures employed when designing task practice to optimize motor skill learn- ing in the context of neurorehabilitation. For skill acquisition, the learner practices under a set of active learning principles that are derived from more mod- ern theories of learning and memory (Cahill et al., 2001) such as those reviewed in Chapter 2 of Volume I. For example, an operant-conditioning model treats “augmented feedback” as a form of “reinforcement” or reward, while a skill-learning model treats “aug- mented feedback” as information about perform- ance for cognitive processing (e.g., problem-solving) relevant to the preparation for the next practice trial.

If augmented feedback operates like positive rein- forcement, designing practice with frequent rewards should enhance learning within an operant- conditioning-based approach. In contrast, if aug- mented feedback operates like post-response information that elicits cognitive processing and problem-solving, designing practice with a faded feedback schedule, where feedback is provided on

progressively fewer trials, should enhance learning within a motor-learning-based approach. Table 7.1 compares and contrasts training principles derived from each of these two learning models (operant con- ditioning and voluntary skill) as they apply to the choice of task practice variables to enhance recovery. In the remaining sections of this chapter, we review the literature and expand the discussion of two of

Table 7.1. Comparison of training principles between operant-conditioning and motor-learning-based interventions.

Practice variable Operant-conditioning training principles Motor-learning training principles

Lifting of learned suppression explains the increased Skill acquisition, motor program, or schema formation use of the affected limb in real-world activities: and the development of internal representations for • Learned-non-use develops from negative action explain the increased functional use of the

reinforcement during the acute stage where affected limb for purposeful, volitional activities: non-reinforced behavior becomes suppressed. • Automatic and implicit procedural knowledge • Successful performance and positive reinforcement develops with practice of motor tasks.

are necessary to lift the suppression allowing the • Tasks are controlled more automatically and with behavior to be expressed in a real-world environment. less cognitive effort; this manifests as skill develops. Amount and Massed practice is essential for cortical re-organization Physical practice is the most important variable for scheduling of and reversal of learned-non-use: motor learning:

practice • “Massed” practice in CIT is the term used to mean • Practice that challenges the learner is motivating intense or extensive practice that is necessary to and optimal for learning-dependent cortical reverse learned-non-use and leads to cortical re-organization.

re-organization. • The term “massed” practice is contrasted with • The optimal duration, intensity, or challenge (level “distributed” practice where within a bout of practice

of difficulty) of practice for enhancing functional the distribution of practice-rest is manipulated. In recovery has not been determined. “massed” practice, there is little to no rest and

performance decrements due to fatigue are generally not considered detrimental to learning. Task progression Shaping of motor behavior is essential especially for Task progression is learning based and depends on an

patients with limited ability: analysis of underlying motor control deficits (strength, • Shaping is based on the idea of successive coordination, etc.):

approximations. • Progression can be accomplished by manipulating a • Guidelines for progression are performance based variety of variables depending on individual needs

and not learning based. (e.g., speed, ROM, adding or freeing degrees of freedom, part-whole task practice).

• These progression techniques are recommended especially for the lower or beginning levels of skill acquisition.

• Task complexity and parameterization within a class of actions are important components of task progression.

these practice variables, augmented feedback and task scheduling, as they relate to motor skill acquisi- tion in neurorehabilitation.

7.5 Conditions of practice to promote