By Hyunjoo Chung, PhD CCC-SLP

The recovery of swallowing function! This is a very important goal of the individuals who suffer from swallowing difficulties. Yet, many of these individuals may not know that swallowing difficulties can improve through swallowing treatment. Clients are less familiar with swallowing exercises and modalities important for the recovery of swallowing function. Let’s go over what will make recovery of swallowing function more achievable through rehabilitative techniques. Successful swallowing rehabilitation involves communication between the client and clinician in the form of rehabilitative feedback and modification.

1. Rehabilitative Techniques (Rosenbek & Jones, 2009): Strength and skills

What is it that we need to strengthen for the recovery of swallowing? Correct. Swallowing muscles. And we need to aim to improve skills for swallowing motion through attention, concentration, and repeated adjustment to tackle the target patterned motion. The essence of these two types of changes (i.e., muscles strengthening and improving skills) is adaptability to therapeutic change elicited. In other words, muscle strengthening exercises and skills for target motions are used to influence plasticity involving swallowing.

2. What can be changed?: Three types of plasticity

Plasticity refers to what is changed with experiences. The three types of plasticity are muscle, behavioral, and neural (Kleim & Jones, 2008). There are principles for the three types of plasticity. These principles are important to have functional goals achieved with minimally wasted therapeutic efforts. Swallowing exercises and therapeutic activities should be guided by the principles. I thought neural plasticity says all about these three types of plasticity. I was wrong although they are closely related to each other. Rosenbeck and Jones suggest that it is the clinician’s responsibility for knowing how to proceed when two principles are conflicting the other in certain cases. Now, are you ready to learn more about each type of plasticity?

Figure 1. Swallowing rehabilitation by promoting muscle plasticity, behavioral plasticity, and neural plasticity.

3. Muscle Plasticity

Two principles of muscle plasticity is specificity and overload. Exactly! You need to do the right exercises aggressively in general. Of course there are some exceptions in which the progressive nature of neuromuscular disorders require customized treatment approach care vs generalized.

Simply speaking, we need to repeatedly implement specific muscle activities against resistance. In addition, the muscle exercises need to be conducted with the intensity beyond the normal to make a physiological change for improvement.

Tongue protrusion or lateralization may serve as a step to attain overall increased tongue strength. Instead, tongue retraction to resistance via effortful swallows or Masako (tongue-hold) maneuver is specific to the tongue motion for swallowing. Shaker exercises or CTAR (chin tuck against resistance) is more specific to improve hyolaryngeal elevation.

Overload principle is easy to comprehend. Let’s experience it! Try to swallow with tongue between teeth (Masako maneuver). This requires more efforts or strength to swallow than the normal effort to swallow.

Clinicians prescribe a frequency and dosage of various exercises based on their clinical judgment. Still, our knowledge is limited in terms of amount of resistance, intensity, and continuing exercises to increase muscle strength and establish its maintenance.

Swallowing muscles consist of more Type II (fast twitching, activated for dynamic activity, disuse atrophy resulting) muscle fibers than Type I (activated for low intensity activity, less fatiguing) muscle fibers. This relates to overload principle. Unless you are overloaded with specific dynamic swallowing activities, Type II swallowing muscles would not be optimally activated. This brings an interesting topic about benefits of neuromuscular electrical stimulation.

4. Behavioral Plasticity

Plasticity involves the ability to change target motion through new learning. Three principles here: the number and spacing of repetitions of the target motion, knowledge of results (KR) & knowledge of performance (KP), and the timing of feedback.

What are knowledge of results (KR) and knowledge of performance (KP)? KR is general feedback to the performance as clinicians provide by indicating whether the performance is correct or incorrect. “Excellent” can be an example of KR that indicates the accuracy of performance. In contrast, KP provides advanced feedback that describes what the client failed and succeeded in with respect to the “physiologic performance” (Rosenbeck & Jones, 2009). KP is crucial to improve swallow function. In the form of KP feedback, the clinician may obtain crucial information interactively about the client’s learning experiences.

Then, the timing of feedback and the number and spacing of repetitions of treatment can be determined to attain best clinical outcomes. I agree. We do have limited knowledge about what schedule of feedback and number/spacing of treatment are most effective for swallowing function.

5. Neural Plasticity: 10 principles (Kleim & Jones, 2008)

Principle 1 may be most familiar to you. Use it or lose it! I love when my client says that. These ten principles are fairly self-explanatory.

• Principle 1: Use It or Lose It (specific brain functions need to be driven to be maintained)

• Principle 2: Use It and Improve It (a specific brain function can be enhanced via training)

• Principle 3: Specificity Matters (the nature of the training experiences determines what is changed)

• Principle 4: Repetition Matters (sufficient repetition is required to influence plasticity)

• Principle 5: Intensity Matters (the degree of change is affected by the intensity; timing of evaluation of the acquisition of the target behavior)

• Principle 6: Time Matters (intervention timing, earlier vs later intervention in the rehabilitation)

• Principle 7: Salience Matters (meaningful tasks induce more plasticity)

• Principle 8: Age Matters (younger nervous systems may be easier to change)

• Principle 9: Transference (generalization of increased skills into similar skills)

• Principle 10: Interference (newly learned maneuvers can interfere with previous swallowing patterns)

6. Clinicians’ Role: “Engage clients to promote their plasticity ”

Clinicians get to meet their clients through their stories and history relating to their current changes and suffering. Clinicians make efforts to understand each client’s experiences and the etiology and factors behind the changes and suffering. In this process, their training and experiences play an important role: they will apply what they have learned as rehabilitative techniques and experiences in various cases to come up with plan of care including exercises and short-term and long-term goals for the client.

The three types of plasticity, muscle plasticity, behavioral plasticity, and neural plasticity should be incorporated based on the clinician’s understanding of individual clients. The knowledge about the client’ primary medical diagnosis and associated factors of swallowing difficulties is essential for a clinician to effectively implement these types of plasticity for his or her client. For instance, a set of multiple swallowing exercises may be recommended to improve swallowing muscles and physiology similarly for various types of clients. At the same time, clinicians need to educate the client and/or family how the set of exercises are coming together for their specific functional goals and provide most effective ways to have the exercises completed. Additionally, neuromuscular diseases such as Guillain-Barre, ALS, MS, and Myasthenia Gravis will need differential approaches due to rapid fatigue and/or progressive degeneration.

7. Client/Family’s Feedback: “Engage your clinician to a new learning”

We know this is not an easy task. I am talking about communication between the client/family and the clinician. As long as the dosage and frequency of exercises are involved, what is done at home on no-therapy days weights more than what is done in therapy only one or twice per week. Clients or family should report how home exercise programs (HEP) are followed up at home to the clinician. That way the clinician can provide further assistance with the HEP to help the client achieve their goals. This can also provide an opportunity to provide further feedback with Knowledge of Performance (KP). Once a HEP is established, follow-up sessions can be used to adjust and promote the client’s performance in the HEP. Clinicians grow through communication with clients and such growth will benefit the client.

8. Collaboration means…

I believe that collaboration starts with mutual understanding of the current state, the client/family/client’s goals, rehabilitative techniques, and a collaborative mindset. The client and clinician would exchange and learn from each other’s experiences, provide feedback to each other, overcome challenges, change approaches as appropriate, and help each other with their goals. There are some challenges in time when a relatively short treatment session needs to be used both for client/family education and client’s exercises. It is clear that we would not be able to achieve our goals with either education or exercises only. We collaborate for both education and exercises to be successful for the client’s and clinician’s goals.

Swallowing rehabilitation was chosen to be the first topic here. Two reasons. One: this is about a subgroup that I would treat most often. Two: learning about dysphagia rehabilitation in context may be more effective in understanding normal and abnormal swallowing. In turn, I can better assist clients with swallowing difficulties.

References

Kleim & Jones (2008). Principles of experience-dependent plasticity: Implication for rehabilitation after brain damage. Journal of Speech, Language, and hearing Research, 51, S225-S239.

Rosenbeck & Jone (2009). Dysphagia in Movement Disorders. San Diego, CA: Plural Publishing.

Miller & Britton (2011). Dysphagia in Neuromuscular Diseases. San Diego, CA: Plural Publishing.