Neuroplasticity- Principles and Applications
Principles of Neuroplasticity
Neuroplasticity is defined by the National Library of Medicine as “the ability of the nervous system to change its activity in response to intrinsic or extrinsic stimuli by reorganizing its structure, functions, or connections after injuries”. The principles of Neuroplasticity guide evidence based neurologic rehabilitation, including physical and occupational therapies. Patients and families who understand these principles will have greater insight into the goals of rehabilitative efforts as well as their role in promoting these principles through a comprehensive home exercise program or daily practice.
The Principles
1.) Use It or Lose It
2.) Use It to Improve It
3.) Specificity
4.) Repetition
5.) Intensity
6.) Time Matters
7.) Salience
8.) Age
9.) Transference
10.) Interference
Explanations
Made popular in physical therapy by this article by Kleim and Jones, these principles have become a staple in rehabilitative practice. These principles serve as guiding ideas behind the selection of interventions as well as their dosage, including their intensity, repetition, and progression.
1.) Use It or Lose It
Essentially, a skill that is not used will be “lost” or “overwritten” by your brain. The analogy I have used before that seems to stick goes like this: When you were in high school, you likely were exposed to algebra and physics. Although you may or may not have done well in those classes, you were likely able to do better on tests then compared to now, as most people do not interact with these subjects on a regular basis in everyday life.
That isn’t to say anything is wrong with you, your brain, or your ability to solve a Pythagorean theorem. As a matter of fact, it means your brain actively decided this information was less important to spend resources retaining than other information, like say your children’s’ birthdays or where your friend from out of town lives. As a finite resource, your brain’s capacity for skills and memories must be managed, and information or skills that are not used with some regularity will fade. This leads well into concept 2.
2.) Use It to Improve It
The other side of the coin is concept 2- skills can be learned and refined through practice. This concept leads to concrete changes in brain structure and function. As discussed in the article linked above, motor skills training in humans and other animals leads to increased cortical reorganization and cerebral cortex plasticity. In layperson’s terms- the skills you practice cause your brain to invest energy into developing the neuronal pathways to better control and scale these skills. The ways in which this practice occurs are important, which guides the remaining principles in this list.
3.) Specificity
Specificity refers to the skills we are looking to improve on. For most patients, skills they look to improve include walking, stairs climbing, floors transfers, chair transfers, and balancing. In order to improve these skills, it is not enough to merely practice the components of these tasks you can already perform. In this article, this is distinguished as “skilled” versus “unskilled” movements. I have found patients typically do not understand this distinction, but better understand the idea of “practicing what you aren’t good at, not what you’re already good at”. By being specific in targeting tasks patients are challenged by, we force your brain to attempt to “figure out” what to do- that is motor learning, and has been found to be a significant driver in rehabilitation and neurorehabilitation.
4.) Repetition
This refers to using a skill on a continued basis beyond initial skill acquisition to drive neuroplasticity and lasting improvement. Similar to principles 1 and 2, the continued reinforcement of a newly acquired skill increases the brain’s development of that skill. To quote the authors, “It is hypothesized that the plasticity brought about through repetition represents the instantiation of of skill within neural circuitry, making the acquired behavior resistant to decay in the absence of training”. Rehabilitation professionals care about this concept for its impact on capacity vs performance. We care that you have the capacity to perform a skill. But we care even more than you have the capacity to perform a skill in a non-structured environment, i.e. outside of therapy, which is performance. As an example: It matters that you relearn to walk, but it matters more that you relearn to walk so well that you do so without a therapist (this is, of course, so you can increase your repetition in this task, further cementing the progress you’ve made).
5.) Intensity
Intensity- in my opinion, one of the most important of these principles for rehabilitation. It isn’t enough to practice a task frequently, we must also strive to practice tasks in a challenging way. While this looks different for every patient, many surrogates for intensity training exist. In physical therapy, we will typically use the Rating of Perceived Exertion (RPE) scale, a 0-10 measure of how hard a patient feels they are working. Many therapists also use heart rate to determine intensity, particularly in activities such as stairs and gait training.
6.) Time Matters
After any neurologic injury, time is a neuroplasticity principle for two major reasons. First, the goal of rehabilitation is to begin recovery training as soon as medically appropriate. It is important to cortical reorganization and motor learning to begin exposing the brain and body to stimuli early in the recovery process. Second, it takes a certain amount of rehabilitation training to see recovery and motor improvements. The process of rehabilitation is exactly that- a process, with intertwined and cascading subcomponents eventually leading to improvement in function that we can appreciate as “getting better”.
7.) Salience
Because we are constantly inundated with sensory inputs, motor tasks, and both conscious and unconscious stimuli, our brains judge the importance and relevance of the world around us. Our brains filter what is “important” from what is “unimportant”.
Let’s give a palpable example: in your daily life, the sensation of your socks- their tightness, how high they sit on your ankle, the way they may sit between or under your toes- is all unimportant to your function. However, by consciously drawing you attention to these sensations, your brain becomes more aware of their presence, despite no change in the amount of sensory input.
Salience in physical therapy and neurorehabilitation follows a related vein. By practicing tasks you consider valuable- commonly transfers, walking, stairs, and balance- we draw more attention both to the successful and unsuccessful components of these tasks. The increased attention to these components, it is postulated, improves your brain’s ability to successfully complete these components and their related tasks. It is the attention to the “important” that leads to improvement.
8.) Age
The age of the individual plays a role in the success of cortical reorganization and learning. Think of Neuroplastic learning as a mental “investment”. When one is young, learning is like investing in stocks- larger returns are possible. as you get older, the returns function more like the bond market- positive returns are possible and often present, but they are more subtle and tend to take more time. Of course, there’s not a set age that your “investment” changes from stocks to bonds, it’s more of a gradual change over time.
9.) Transference
This principle explains the positive inter-relation between two tasks. It is possible to improve a skill by practicing others that are similar but unrelated. A common example is instrument playing- the same fine motor skills that helps a pianist play may help them learn to play other instruments, like the guitar, that require related fine motor control.
10.) Interference
Lastly, the other side of the coin- practicing one skill may take away from the ability to perform another skill. This is observable in Olympic sports like the triple jump- although many athletes may have the physical capacity to participate, the particular skill required to complete this activity is not improved by being good at other events like sprinting or throwing.
Take Aways
The principles of Neuroplasticity offer a very broad framework through which rehabilitation professionals attempt to stimulate motor learning. The overarching goal of these principles is to guide rehab professionals to interventions and strategies that result in improved function- whether that be balance, walking speed, endurance, independence, or confidence in yourself. All rehabilitation professionals working with patients with patients with neurologic conditions should know and actively use principles of Neuroplasticity to guide treatments and plans of care.
If you or someone you know has a neurologic condition, we would be happy to help. Please reach out to our office at the phone number or email address below, or through our “contact us” page.
