The Think System Makes Its Way From River City, Iowa, to Belo Horizonte, Brazil
May 2018 Issue
While the demographic of the O&P profession continues to get a bit younger with each passing year, I suspect many readers will recall the scene in The Music Man when the citizens of River City, Iowa, had a spot of trouble on their hands. They were innocently unaware of their problems until the traveling professor Harold Hill came into town to rhythmically explain:
Well, ya got trouble, folks
Right here in River City
Trouble with a capital T
And that rhymes with P
And that stands for pool….
With the introduction of the town's first pool table, degenerate adolescent behavior was almost certainly right around the corner. Fortunately, Professor Hill, also known as the Music Man, had just the thing to keep young minds otherwise engaged with the creation of a boys' brass band. And the good professor was more than happy to arrange for the purchase of the necessary instruments and uniforms.
Those familiar with the story will recall one troubling detail in Hill's plan—his inability to actually teach the boys of the town how to play. But to bide his time until the ordered supplies were paid for and delivered, Professor Hill devised what he called the Think Method.
The method is explained in an exchange between Hill and the town librarian, Marian, older sister to the fledgling cornet player, Winthrop.
"I've been wanting to talk to you about Winthrop's cornet," Marian says. "You see, he never touches it. Oh, the first week or so he made a few experimental blats…. And he sings the Minuet in G almost constantly. But he never touches the cornet. He says you told him it wasn't necessary. He tells me about some ‘Think System.' If he thinks the Minuet in G, he won't have to bother with the notes."
Those familiar with the production will remember that, fortunately for the Music Man, the Think System worked just well enough to keep him from being run out of town, with the boys producing a passable rendition of the Minuet in G, made more palatable by the hopeful ears of proud parents.
While the Think System serves as a ruse in the musical, a similar premise called Mental Practice has been explored with some success in rehabilitation medicine in Brazil. This article introduces rehabilitative Mental Practice as described by the Brazilian team and relays its effects among individuals recovering from stroke and those relearning gait following lower-limb amputation.
Given Professor Hill's reluctance to articulate the finer points of the Think System, we turn to the Brazilian clinicians for a better understanding of rehabilitative Mental Practice. The advocates of this approach summarize Mental Practice as "a method by which the internal reproduction of a given motor act is extensively repeated with the intention of improving performance," and as "a mental rehearsal of kinesthetic and/or visual properties of movements."1 During Mental Practice, "an internal representation of the movement is activated and its execution is mentally repeated without physical activity."1 Thus, Mental Practice is described as "a cognitive strategy, which may benefit the acquisition of motor skills and the functional performance of…individuals with neurological injuries.1
Within this context, the Brazilian team set out to determine whether specific, functional task-oriented Mental Practice, when added to conventional physical therapy, would promote better motor skills learning in individuals with chronic post-stroke impairment.
To do so, they recruited nine subjects who were an average of 13 months post-stroke with mild to moderate impairment of their dominant upper limb. Of note, subjects were excluded from the study if they had profound contractures in the affected limb, meaning all subjects had to demonstrate at least 10 degrees of movement at the affected wrist and metacarpophalangeal and interphalangeal joints of the index finger and thumb. Additional exclusionary criteria were spasticity of three or more on the modified Ashworth scale and excessive pain in the paretic limb.1
The clinical trial was executed in an A-B-A fashion, with one month of conventional therapy followed by a month of therapy with supplemental Mental Practice and an additional month of conventional therapy only. Assessments were performed at baseline and following each of the one-month treatment sessions.
The initial and concluding A conditions consisted of 30-minute therapy sessions comprising five minutes of mild stretching, 20 minutes of strengthening, and five minutes of muscular relaxation with an emphasis on stretching the flexor muscles and strengthening the affected shoulder, elbow, and wrist joints.
The B condition requires a more detailed explanation. Subjects attempted to perform a series of tasks of increasing difficulty and complexity, paying attention to how they attempted them. They were then asked to divide these tasks into individual physical components. For example, the authors describe a grasping activity that was broken down into shoulder elevation, elbow extension, pre-positioning the hand over the object, and grasping the object. Once subjects were able to identify and describe the individual components of each task, they were asked to imagine performing the tasks ten times without physically executing them. After this exercise, they were instructed to imagine each task ten additional times while describing the individual movement components. Shortly after the Mental Practice, subjects were asked to describe each component of the task again, performing each component in isolation and then executing the movement pattern. The training sessions were conducted in 30-minute sessions, three days per week for four weeks.1
The efficacy of the interventions was tracked in several ways. The Brazilian version of a motor activity log recorded both the amount and quality of use of the impaired limb using 30 self-report items scored on a scale from one to five, with higher scores suggesting better performance. These scores were unchanged between baseline and the conclusion of the four-week therapy-only condition. However, at the end of the combined interventions, the introduction of Mental Practice alongside functional task performance attempts yielded meaningful results, with average scores for both the amount of use and quality of movement improving from about one to about three, an improvement that was retained following an additional four weeks of stretching and strengthening only.1
These self-reports were supplemented by performance on the "placing" subtest of the Minnesota Manual Dexterity Test in which subjects place 60 short, round blocks. Here again, performances at baseline and after four weeks of stretching and strengthening were unchanged, averaging about ten blocks per minute. Following four weeks of Mental Practice, this improved to just over 16 blocks per minute, an improvement that was retained after the final four weeks of stretching and strengthening only.1
Several years after their publication about Mental Practice in stroke rehabilitation, the authors returned with a second publication about the use of Mental Practice in gait training for people with lower-limb amputations. As the aims of amputee gait training can be contentious, it should be noted that for this group, the aims of therapy were suggested as minimizing greater oscillations of the center of mass and reducing energy expenditure and/or pain even if the gait pattern remains kinematically asymmetrical.2 Within this construct, the efficacy of the interventions was measured with the use of a force plate under the prosthetic limb, determining changes to vertical, sagittal, and coronal ground reaction forces.2
The study was largely patterned after the stroke effort, using an A-B-A trial sequence with four weeks in each condition and assessments performed at baseline and the conclusion of each condition. However, in contrast to the previous effort where the control condition was inclusive of some form of physical therapy, in this trial the subjects in the control condition received no physical intervention of any kind during the four-week A condition.
Once the experimental subjects entered the second arm of the trial, they moved through a series of increasingly difficult tasks, imagining each task ten times before describing the individual movements required at each joint. These tasks included basic maneuvers such as sit-to-stand transfers from a chair and walking with the prosthesis, more advanced tasks such as jumping, and running and walking up a staircase or a ramp, and still more challenging tasks such as zig-zag running and walking down stairs and ramps. After each Mental Practice session, those subjects in the experimental group physically performed the tasks themselves to actuate the imagined tasks.2
As mentioned, those in the control group received no physical intervention at all during this second arm of the trial but were simply asked to imagine things like life goals, trips, family relationships, or moments of happiness. After four weeks in the two different conditions, subjects spent an additional four weeks with no interventions of any kind prior to a final round of testing.
It's not hard to predict that those in the control arm of the trial experienced no meaningful changes in their gait, as they weren't asked to do anything but spend four weeks thinking about non-physical activities.
In contrast, those in the experimental arm of the trial realized some meaningful improvement. For example, the first vertical peak of the ground reaction force, experienced during heel strike, reduced from an average of 90 percent of body weight to an average of 77 percent of body weight after four weeks of Mental Practice with concurrent physical performance, suggestive of increased shock attenuation during weight acceptance.2 Similarly the second vertical peak of the ground reaction force, experienced during push-up, increased from an average 63 percent body weight to an average of 80 percent body weight after four weeks of mental and physical practice. This latter variable suggests the patients learned to keep their weight on their prosthesis through more of their stride, producing increased propulsive capacity.
Additionally, the support period on the prosthetic limb increased from an average of 0.42 seconds to 0.647 seconds, also suggestive of increased confidence and utilization of the prosthesis as weight is carried through the prosthesis through the entire stride.2
The benefits experienced by those in the mental and physical practice group were superior enough to alter the execution of the study. While the initial study had randomly divided participants into two eight-person cohorts, after a preliminary analysis of the first five subjects from each group, the control group was effectively called off, with the remaining subjects moved over to the experimental group. This was done under the rationale that "it would not be scientifically ethical to expose the volunteers to a specific intervention that did not support the significant results seen in gait function."
Unfortunately, neither of the Brazilian studies can really tell us if Professor Harold Hill was right. In both efforts, Mental Practice was always performed in concert with physical therapy and appeared to produce objective improvements. However, the control conditions were too removed from the experimental conditions to isolate the possible effects of Mental Practice. The control condition in the stroke study was stretching and strengthening rather than functional training, and the control condition in the amputee group was thinking of things other than walking with no gait training. However, the trials both suggest that Mental Practice, functional therapy, or a combination of the two yield beneficial effects. The ultimate impact of Mental Practice will require trials in which functional therapy is provided throughout all conditions with the isolated addition and removal of Mental Practice. Until then, we'll just have to keep humming to get ready for our next band concert.
Phil Stevens, MEd, CPO, FAAOP, is in clinical practice with Hanger Clinic, Salt Lake City. He can be contacted at firstname.lastname@example.org.
1. Santos-Couto-Pazz, C., L. F. Teixeira-Salmela, and C. J. Tierra-Criollo. 2013. The addition of functional task-oriented mental practice to conventional physical therapy improves motor skills in daily functions after stroke. Brazilian Journal of Physical Therapy 17(6):564-71.
2. Cunha, R. G. et al. 2017. Influence of functional task-oriented mental practice on the gait of transtibial amputees: a randomized, clinical trial. Journal of Neuroengineering and Rehabilitation 14:28.