Co-author: Angela Van Sickle, PhD, CCC-SLP
The Educational Disadvantage
Based on social media, there seems to be an ongoing tension between academia and practicing clinicians. Many new clinicians enter the workforce; they begin to learn the complexity of actual patients. Many patients have complex medical histories and assessment, and treatment is not as black and white as the pages of a dysphagia textbook. To compound the problem, the typical speech pathologist divides time treating multiple disorders making it difficult to focus learning in one area of practice (i.e., dysphagia). When reality sets in, the clinician points a finger back at their University professors and asks, “Why didn’t you prepare me” or “Why didn’t I learn this in graduate school?”
Consider, how a professor might teach the skills necessary to understand the complexity of dysphagia to students who do not have the proper foundation? When comparing the difference in SLP education to the education of a physical therapist, obvious differences emerge. Examination of the curriculum of a physical therapy program revealed the requirements include seven (academic) hours of gross anatomy, four hours of kinesiology, three hours of exercise physiology, four hours of microscopic anatomy, four hours of neuroanatomy, and three hours in foundations of rehabilitation. Examining a Speech pathology program in the same geographical location reveals a requirement of three hours of anatomy and physiology of speech and hearing and three hours that combine neuroanatomy and neurogenic communication disorders. The difference is twenty-one academic hours of foundational information versus less than six. Meaning, PTs have about 945 clock hours of instruction concerning normal processes compared to 68 hours for the SLP. Although anatomy and physiology may be taught in other courses, the findings indicate that instructors providing education in SLP programs are not given the time to teach many necessary skills.
The Workplace Disadvantage
After graduation, the problem is compounded. Most employers do not allow time for learning during work hours, as investigating a patient’s disorder is not billable. Additionally, SLPs are asked to provide treatment with a few picture cards, tongue depressors, and some workbooks, while our PT colleagues have thousands of dollars of equipment (parallel bars, recumbent bikes, free weights, treadmills, balance boards, etc.). The synergistic effect often leads SLPs to deliver therapy that resembles a cookbook: Taco Tuesday translates to Masakos for tongue base retraction.
When a SLP decides to advance their knowledge, more hurdles arise. For example, some continuing education courses offer a specific approach, promoting a single solution for a complex problem. There are also resources that provide discussions concerning specific patient cases. The issue is that the person providing advice does not know the patient. Additionally, the bias and experience of the respondent is not evident. While such avenues may provide well-meaning advice and may allow the concerned SLP to put a band-aid on a specific situation, they can also lead to overgeneralization and poor application of interventions. As Maslow (of the hierarchy fame) said, “To a man with a hammer, everything looks like a nail.” Without a solid foundation, it is difficult to determine the appropriateness of an intervention. So, how do clinicians begin to dig out of this hole?
The Building Process
The provision of quality assessment and intervention of dysphagia therapy requires the SLP to have a framework that supports critical thinking. The first step in developing critical thinking skills is to have a sufficient body of knowledge. Critical thinking is enabled by extensive stores of knowledge concerning the subject matter. 1
The most obvious place to begin building knowledge in swallowing is to learn anatomy and physiology. Understanding “normal” swallowing is fundamental to evaluation and treatment. 2-9 Unfortunately, several barriers may have led to a lack of knowledge in this area. The anatomy and physiology course is typically required in undergraduate school. At that time, students may have difficulty connecting the information to patient care. In addition, the information, when learned in a silo, seems quite boring. Consequently, students memorize origin, insertion, function, and innervation to pass a test and then move on to more interesting pursuits.
When dealing with patients, the understanding of anatomy and physiology can be interesting. For example, if a hoarse voice is noted during a clinical swallow, the astute clinician considers other possibilities. If the Vagus nerve (CN X) is impaired, that means the patient may have impaired laryngeal vestibular closure (since the iSLN and the recurrent laryngeal nerve are both branches of CN X).Could it mean there are issues with the pharyngeal plexus and pharyngoesophageal segment (also X)? 10 Checking the elevation of the soft palate may provide additional information. Does the palate elevate? Does the uvula deviate to one side? Instead of facilitating a yawn, the knowledge becomes dynamic and intriguing.
Learning anatomy and physiology does not require a continuing education course. Just grab a textbook off the shelf. There are a finite number of muscles and nerves. To make the process more enjoyable, challenge your colleagues or start a Zoom group to facilitate learning. In addition to textbooks, consider the articles in table 1. Some contain information concerning anatomy and physiology, and others examine the profession’s current knowledge.
Principles of Exercise
Besides anatomy and physiology, there is value in learning the principles of exercise. Unfortunately, the term “exercise” conjures up many mental pictures, someone sweating in a gym, weights, and a Mendelsohn Maneuver. Interestingly, a member of a profession (SLP) that provides rehabilitative interventions may graduate without learning exercise principles. SLPs talk about “exercise” and ask our patients to perform “exercises,” but do we have the skills to apply the principles?
Simply put, therapeutic exercise involves movement prescribed to correct impairments, restore muscular and skeletal function and/or maintain a state of well-being11. There are widely accepted exercise principles that should guide treatment. They include individuality, specificity, overload, progression, and reversibility.
Individuality refers to the need to adapt interventions to the individual. 12 The principle requires the SLP to consider the patient’s overall health, etiology of the dysphagia, and the specific swallowing pathophysiology. The principle of specificity refers to how closely the exercise task replicates the targeted outcome 13. In the case of swallowing, it seems interventions that incorporate a swallow would yield the best outcomes. Overload suggests a system must be pushed beyond its normal level of function13. Simply practicing a routine activity (i.e., eating a meal of pureed food and thickened liquid) will most likely not push the system to change. 14 As patients improve, the intervention should become progressively more challenging. It is important to be aware that when training is stopped, some of the effects may diminish with time. 13
The incorporation of exercise principles provides guidance for both assessment and treatment. The principles suggest the need to understand the history and current status of the patient and not just what is happening in their mouth and neck. To develop a treatment plan that is individualized and specific, it is necessary to have information concerning the patient’s specific impairment. This pushes SLPs to provide investigation beyond noting signs and symptoms of dysphagia as treating a cough or throat clear lacks specificity. Knowing exercise requires overload would steer the clinician away from a practice of meal observation.
While exercise principles may seem to suggest strength training, the literature suggests two possible benefits, neural factors, and hypertrophic factors. 15 Although strength training eventually causes changes in muscle, the changes cannot account for all the increases in strength as significant strength gains occur before muscle hypertrophy. 16 The central nervous system also contributes to training-dependent increases in strength. Improvements in the rate of force production and maximum contractions may contribute to physiologic changes more than muscle hypertrophy 17. There is evidence that high-intensity training causes gains in firing frequency and synchronization of action potentials. 18 Such changes may be a positive impact on swallowing. Great neural adaptations occur in higher intensity exercise (80%of one repetition maximum) compared to low-intensity exercise (30% one repetition maximum). The findings indicate exercise intensity influences strength gains by facilitating neurologic changes. 19, 20
An understanding of exercise principles will not answer all SLP questions concerning the appropriateness of a particular intervention. However, it will provide clinicians with information to use when critically assessing a proposed intervention and may provide guidance concerning exercise dosage. To take a deeper dive, check out the bibliography and see table 1 for a list of recommended articles.
As mentioned, exercise may facilitate neurologic changes. What is the goal of rehabilitation? Is the plan to change behaviors (i.e., how individuals respond to stimuli) or change the brain (i.e., learn/relearn skills for lasting improvements)?14 “Neural plasticity is believed to be the basis for both learning in the intact brain and relearning in the damaged brain that occurs through physical rehabilitation” 21 (p. S225). If changing the brain and relearning skills is the goal, then knowing and applying principles of neural plasticity to rehabilitation should be a part of critical thinking for each patient.
Kleim and Jones21 summarized and provided preliminary evidence for 10 principles of experience-dependent neural plasticity: use it or lose it, use it and improve it, specificity, repetition, intensity, timing, salience, age, transference, and interference. A brief description of each principle, summarized from this article, is provided here. These principles provide guidelines. The exact applications for each principle may require further research.
Use it or lose it is a common phrase. The principles of use it or lose it and use it and improve it relate to performing a task to allow the individual to continue to perform the task and possibly improve it. In addition, these principles refer to using and improving neural connections22. Studies showed a disruption in neural connections and may cause a decrease in the number of synapses with decreased use. 23 Through rehabilitation, individuals practice skills, thereby possibly reducing loss of connections (i.e., use it or lose it) and/or creating new connections in other intact areas of the brain (i.e., use it and improve it. During rehabilitation, changes in the brain may occur and improve synaptic plasticity as complexity increases.21
Specificity is related to the types of tasks that create neural changes. Kleim and Jones21 state that “specific forms of neural plasticity and concomitant behavioral changes are dependent upon specific kinds of experience” (p. S229). That is, training to improve swallowing must include experiences/tasks related to swallowing. Specific rehabilitation of one modality (e.g., speech) may not improve functioning for another (e.g., swallowing).
The neural plasticity principle of repetition is included in principles of exercise and principles of motor learning. Repetition of tasks is required to become skilled at those tasks, but repetition alone, may not promote neural plasticity. Repetition of a task acquired previously may not change the brain, but repetition of a newly learned or relearned task may create changes. In addition, repetition of tasks of increasing complexity may create changes (See how this applies to motor learning below).
Along with repetition, the intensity of training is also essential. How many repetitions of a specific exercise are needed for change? How many sessions are required with X number of repetitions? How many weeks of sessions are required? Kleim and Jones21 suggested that if repetitions are too low, increases in synapses may not occur. On the other hand, if the number of repetitions is too high, the overuse could result in increased tissue damage or loss during certain periods of recovery. Determining the balance is a combination of art and science,24 The art of making such decisions can be improved through the meticulous collection of clinical data (more on this later).
As with overuse, the timing of treatment must be considered. When is the best time to begin treatment? Kleim and Jones21 explained that introducing treatment in the early stages of recovery may prevent some of the loss of representation in the brain and may promote increased outcomes. Conversely, treatment occurring too early after injury may result in increased degradation due to the fragile state of the tissue. In addition, if treatment is delayed, individuals may acquire compensatory strategies that may inhibit relearning. It is challenging to know the intensity of training or the best time to initiate treatment.
Salience refers to the importance of an experience. The more salient or relevant the experience, the more likely learning occurs. There is research demonstrating enhanced plasticity with increased saliency21. This principle may help shape therapy goals. For example, if improving swallowing to eat favorite foods is important or relevant to a patient, would swallowing tasks or performing oral motor exercises be more salient?
A patient’s age is another principle to consider as neural plasticity is more difficult to attain with age. It has been suggested that plasticity is the mechanism by which the brain compensates for aging.21 Research has shown the benefits of complex stimuli and environments for younger and older animals. This is important for rehabilitation. Even if aged brains respond slower and less effectively, the complex stimuli and environments provided in rehabilitation may promote behavioral and neural plasticity.
Transference and interference are two final principles summarized by Kleim and Jones. They reviewed research, which showed that training a skill may increase excitability and representation in related areas of the brain (i.e., transference), but some forms of plasticity may cause interference with learning. They provided the following examples of transference and interference. Transcranial cortical stimulation provided at the time of training has been shown to facilitate performance, but stimulation provided without the training experience (e.g., before or after training the task) may create plasticity that is not related to the function being targeted. Compensatory strategies acquired following brain injury may cause plasticity that interferes with relearning. Plasticity from rehabilitation on one task may interfere with performance on another. It is difficult to know if a task is going to promote transference or interference21.
Continued research focusing on timing for rehabilitation, appropriate amounts of repetition, the intensity of treatment, and tasks that enhance transference and reduce interference is needed. Applying these ten principles of experience-dependent neural plasticity to research and rehabilitation may improve functional outcomes. A companion article by Robbins et al.14 initiated this process with swallowing and swallowing disorders.
In the companion article, Robbins and colleagues theorize possible connections between the ten principles of neural plasticity and swallowing rehabilitation. The article, “Swallowing and Dysphagia Rehabilitation: Translating Principles of Neural Plasticity Into Clinically Oriented Evidence,” provides an example of critical thinking skills. Possible applications are outlined, using research to support their hypotheses.
Each principle and its specific application to swallowing rehabilitation requires continued research to inform speech-language pathologists about using strategies to improve swallowing. In the meantime, thinking through these principles, as they relate to swallowing strategies, may help guide decision-making for specific patients. For example, Robbins and colleagues point out how the “use it or lose it” principle may apply when considering individuals receiving tube-feedings. These individuals may demonstrate reduced swallowing skills with disuse or a reduced number of swallows while receiving tube feedings. The authors suggested such individuals may benefit from “dry” swallow exercises to reduce the chance of losing the skill and possibly losing cortical representation for swallowing before rehabilitation starts.14 So, after learning a new strategy at a recent continuing education course or in a recent article, it may be beneficial to look at the strategy and determine if it incorporates the principles of neuroplasticity. Does the strategy implement any of the principles of neural plasticity? Does the strategy require repetition? Will repetition of the strategy improve swallowing? Does the strategy incorporate a specific experience that may affect swallowing? Does the strategy make sense for a specific patient based on age or timing? These questions are part of critical thinking.
Motor learning is the process associated with practice that leads to a relatively permanent change in a movement. 25 At a basic level, the principles of motor learning include task specificity, an evolving challenge, and feedback. 26-28
The principle of specificity shows up again. In motor learning, the principle suggests the ability to perform one motor skill effectively is independent of the ability to perform other motor skills. Because generalization of a motor skill cannot be anticipated, 29-31 interventions should include the targeted task.
The incorporation of an evolving challenge, rather than rote memorization, is needed. 32 When considering the task challenge, it is important to consider both nominal difficulty and skill difficulty. Nominal task difficulty is constant regardless of who is performing the activity or the conditions of performance. It considers factors such as the perceptual and motor performance needed to achieve the desired outcome, but not the person performing the task. For example, efficient, safe walking on a sidewalk requires the same skills from everyone. Functional task difficulty refers to how challenging the task is relative to the individual’s skill level and the conditions under which it is being performed 33. Using the previous example, for someone with a visual impairment and a prothesis, walking on the sidewalk poses a higher level of difficulty. When developing targets for swallowing therapy, it is vital to understand the nominal task requirements for performing a specific intervention and the task difficulty for the patient. For example, when asking the patient to perform an effortful swallow, the instructions may be, Push your tongue against the roof of your mouth and squeeze all the muscles of your neck and throat. 34 The task requires the cognitive ability to understand multistep directions, adequate lingual range of motion, lingual sensation, etc. Individual differences might include a decreased lingual range of motion, decreased lingual sensation, and impaired cognition. When developing a task challenge, both the task requirements and the patient’s unique presentation need to be considered.
The third component of motor learning is feedback. 32, 35, 36 Successful motor learning relies on accurate feedback 32. Feedback can come from an internal source (intrinsic), an external source (extrinsic), or a combination of the two. Intrinsic feedback is the knowledge the learner receives from their own sensory-perceptual information such as vision, proprioception, touch, pressure, and audition. 37 Extrinsic feedback is information provided from an external source 32, 38. For example, extrinsic feedback can be provided with a mirror, auditory instructions, or a biofeedback device.20 It may be important to consider that external feedback may be helpful as intrinsic feedback may be compromised or inaccurate in an impaired system. 39
Two forms of extrinsic feedback are knowledge of results and knowledge of performance. Knowledge of results is external information allowing the individual to know if the desired target was achieved or not. 40, 41 Knowledge of performance is information concerning the movement characteristics that led to the performance outcome. 40 It is possible to learn motor tasks without extrinsic feedback; however, the motor learning literature suggests improved retention of motor patterns when external feedback is used 41-43 as external feedback can provide information regarding a movement and how to modulate a movement.
Putting Knowledge into Action
Knowing information is fun. Maybe one day, it will assist in answering a question on Jeopardy. But what is the point? Once a knowledge base is established, what is next? How does knowledge translate into critical thinking to make clinical decisions? Suppose a new patient arrives in the clinic. The patient is assessed, and the pathophysiology is identified. A colleague recommends a specific intervention, or perhaps there is a promising research article concerning a behavioral intervention that may be helpful. The information concerning exercise science, motor learning, and neuroplasticity can be used to determine if the suggested invention has the potential to impact swallow physiology? Are the correct muscles involved? Is the correct aspect of the swallow (timing or kinematics) being targeted? If the intervention meets the criteria, the next steps would be to try out the activity, collect data and analyze the data to determine if the intervention made a difference. Collection and analysis of patient outcome data builds a body of information that can be called clinical experience.
The authors do not suggest the information provided is a comprehensive list of the information required for critical thinking related to the management of swallowing disorders. Among the areas not covered are the impact of conditions and disease states on recovery, pharmacology, nutrition and hydration, and the complexities of the respiratory system. Additionally, the clinician needs to consider the quality of research used to support any intervention. The road to knowledge is long and can be challenging. The good news is that the progress of gaining knowledge can be measured incrementally, one bit of information at a time. Now the proverbial ball is in your court. Take some time to set goals for learning. Will it be one article a week? Two per month? Will it be starting a journal club to review the information with colleagues? Perhaps it will be developing a robust data collection system? There are many possibilities, but it is worth the journey because patients are counting on you!
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3. Khosh MM, Krespi YP. Swallowing physiology. Operative Techniques in Otolaryngology-Head and Neck Surgery. 1997;8(4):182-184. doi:10.1016/s1043-1810(97)80027-9
4. Rademaker AW, Pauloski BR, Colangelo LA, Logemann JA. Age and Volume Effects on Liquid Swallowing Function in Normal Women. Journal of Speech, Language, and Hearing Research. 1998;41(2):275-284. doi:doi:10.1044/jslhr.4102.275
5. Logemann JA. Evaluation and Treatment of Swallowing Disorders. American Journal of Speech-Language Pathology. 1994;3(3):41-44. doi:doi:10.1044/1058-0360.0303.41
6. Humbert IA, Robbins J. Normal Swallowing and Functional Magnetic Resonance Imaging: A Systematic Review. Dysphagia. 2007;22(3):266-275. doi:10.1007/s00455-007-9080-9
7. Wooi M, Scott A, Perry A. Teaching Speech Pathology Students the Interpretation of Videofluoroscopic Swallowing Studies. Dysphagia. 2001;16(1):32-39. doi:10.1007/s004550000040
8. Chavan K. Anatmony of Swallowing. In: Mankerkar G, ed. Swallowing-Physiology, Disorders, Diagnosis and Therapy Springer; 2015.
9. Jardine M, Miles A, Allen J. A Systematic Review of Physiological Changes in Swallowing in the Oldest Old. Dysphagia. 2020;35(3):509-532. doi:10.1007/s00455-019-10056-3
10. Love R, Webb W. Neurology for the speech-language pathologist. Butterworth-Heinemann; 2001.
11. Garber CE, Blissmer B, Deschenes MR, et al. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. Jul 2011;43(7):1334-59. doi:10.1249/MSS.0b013e318213fefb
12. Powers S, Howley, E. Exercise Physilogy. 4th ed. McGraw-Hill; 2001.
13. Burkhead LM, Sapienza CM, Rosenbek JC. Strength-Training Exercise in Dysphagia Rehabilitation: Principles, Procedures, and Directions for Future Research. Dysphagia. 2007;22(3):251-265. doi:10.1007/s00455-006-9074-z
14. Robbins J, Butler SG, Daniels SK, et al. Swallowing and dysphagia rehabilitation: translating principles of neural plasticity into clinically oriented evidence. J Speech Lang Hear Res. Feb 2008;51(1):S276-300. doi:10.1044/1092-4388(2008/021)
15. Moritani T. Time course of adaptations during strength and power training. In: Komi P, ed. Strength and Power in Sport. Blackwell Scientific Publications; 1992:266-278.
16. Akima H, Takahashi H, Kuno S, et al. Early phase adaptations of muscle use and strength to isokinetic training. Medicine & Science in Sports & Exercise. 1999;34(4):588-594.
17. Unhjem R, Lundestad R, Fimland MS, Mosti MP, Wang E. Strength training-induced responses in older adults: attenuation of descending neural drive with age. AGE. 2015;37(3)doi:10.1007/s11357-015-9784-y
18. Folland JP, Williams AG. The Adaptations to Strength Training. Sports Medicine. 2007;37(2):145-168. doi:10.2165/00007256-200737020-00004
19. Jenkins N, Miramonti A, Hill E, et al. Greater Neural Adaptations following High- vs. Low-Load Resistance Training. Original Research. Frontiers in Physiology. 2017-May-29 2017;8(331)doi:10.3389/fphys.2017.00331
20. Galek K, Bice E, Allen K. A Novel Protocol Designed to Treat Spastic Dysarthria Due to a Traumatic Brain Injury: A Case Study. Perspectives of ASHA Special Interest Groups SIG 2. 2021;In press
21. Kleim J, Jones T. Principles of Experience-Dependent Neural Plasticity: Implications for Rehabilitation After Brain Damage. Journal of Speech, Language, and Hearing Research. 2008;51(1):S225. doi:10.1044/1092-4388(2008/018)
22. Cramer SC, Sur M, Dobkin BH, et al. Harnessing neuroplasticity for clinical applications. Brain. 2011;134(6):1591-1609. doi:10.1093/brain/awr039
23. Jones TA, Chu CJ, Grande LA, Gregory AD. Motor Skills Training Enhances Lesion-Induced Structural Plasticity in the Motor Cortex of Adult Rats. The Journal of Neuroscience. 1999;19(22):10153-10163. doi:10.1523/jneurosci.19-22-10153.1999
24. Brody LT. Effective Therapeutic Exercise Prescription: The Right Exercise at the Right Dose. Journal of Hand Therapy. 2012;25(2):220-232. doi:10.1016/j.jht.2011.09.009
25. Lee TD, Swinnen SP, Serrien DJ. Cognitive Effort and Motor Learning. Quest. 1994;46(3):328-344. doi:10.1080/00336297.1994.10484130
26. Huckabee ML. Rethinking Rehab: Skill-Based Training for Swallowing Impairment. 2014;23:46-53.
27. Halsband U, Lange RK. Motor learning in man: a review of functional and clinical studies. J Physiol Paris. Jun 2006;99(4-6):414-24. doi:10.1016/j.jphysparis.2006.03.007
28. Luft A, Buitrago, M. Stages of motor skill learning. Molecular Neurobilogy. 2005;32:205-216.
29. Barnett ML, Ross D, Schmidt RA, Todd B. Motor Skills Learning and the Specificity of Training Principle. Research Quarterly American Association for Health, Physical Education and Recreation. 1973/12/01 1973;44(4):440-447. doi:10.1080/10671188.1973.10615224
30. Wulf G, Shea CH. Principles derived from the study of simple skills do not generalize to complex skill learning. Psychonomic Bulletin & Review. 2002;9(2):185-211. doi:10.3758/bf03196276
31. Maas E, Robin DA, Austermann Hula SN, et al. Principles of Motor Learning in Treatment of Motor Speech Disorders. American Journal of Speech-Language Pathology. 2008;17(3):277-298. doi:10.1044/1058-0360(2008/025)
32. Rose D, Christina, R. Multilevel Approach to the Study of Motor Control and Learning. 2 ed. Pearson/Benjamin Cummings; 2006.
33. Guadagnoli M, Lee T. Challenge point: a framework for conceptualizing the effects of various practice conditions in motor learning. J Mot Behav. 2004;36(2):212-224.
34. Huckabee ML, Steele CM. An analysis of lingual contribution to submental surface electromyographic measures and pharyngeal pressure during effortful swallow. Arch Phys Med Rehabil. Aug 2006;87(8):1067-72. doi:10.1016/j.apmr.2006.04.019
35. Sharma DA, Chevidikunnan MF, Khan FR, Gaowgzeh RA. Effectiveness of knowledge of result and knowledge of performance in the learning of a skilled motor activity by healthy young adults. Journal of Physical Therapy Science. 2016;28(5):1482-1486. doi:10.1589/jpts.28.1482
36. Hundal P. Knowledge of perfromance as an incentive in repetitive industrial work. Journal of Applied Psychology. 1969;53(3)(1):224-226.
37. Schmidt RA, Lee TD. Motor Control and Learning: A Behavioral Emphasis. 5th ed. Human Kinetics; 2011.
38. Sheppard JJ. Using Motor Learning Approaches for Treating Swallowing and Feeding Disorders: A Review. Language, Speech, and Hearing Services in Schools. 2008;39(2):227-236. doi:doi:10.1044/0161-1461(2008/022)
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Table 1. Anatomy and Physiology
|Dickson RP, Erb-Downward JR, Huffnagle GB. Towards an ecology of the lung: new conceptual models of pulmonary microbiology and pneumonia pathogenesis. Lancet Respir Med. 2014 Mar;2(3):238-46. doi: 10.1016/S2213-2600(14)70028-1. PMID: 24621685; PMCID: PMC4004084.|
|Humbert IA, Fitzgerald ME, McLaren DG, Johnson S, Porcaro E, Kosmatka K, Hind J, Robbins J. Neurophysiology of swallowing: effects of age and bolus type. Neuroimage. 2009 Feb 1;44(3):982-91. doi: 10.1016/j.neuroimage.2008.10.012. Epub 2008 Oct 28. PMID: 19010424; PMCID: PMC2630466.|
|Jean A. Brain stem control of swallowing: neuronal network and cellular mechanisms. Physiol Rev. 2001 Apr;81(2):929-69. doi: 10.1152/physrev.2001.81.2.929. PMID: 11274347.|
|Komiya K, Ishii H, Kadota J. Healthcare-associated Pneumonia and Aspiration Pneumonia. Aging Dis. 2014 Feb 8;6(1):27-37. doi: 10.14336/AD.2014.0127. PMID: 25657850; PMCID: PMC4306471.|
|Ludlow CL. Laryngeal Reflexes: Physiology, Technique, and Clinical Use. J Clin Neurophysiol. 2015 Aug;32(4):284-93. doi: 10.1097/WNP.0000000000000187. PMID: 26241237; PMCID: PMC4527097.|
|Malandraki GA, Johnson S, Robbins J. Functional MRI of swallowing: from neurophysiology to neuroplasticity. Head Neck. 2011 Oct;33 Suppl 1(0 1):S14-20. doi: 10.1002/hed.21903. Epub 2011 Sep 7. PMID: 21901779; PMCID: PMC3747973.|
|Molfenter SM, Hsu CY, Lu Y, Lazarus CL. Alterations to Swallowing Physiology as the Result of Effortful Swallowing in Healthy Seniors. Dysphagia. 2018 Jun;33(3):380-388. doi: 10.1007/s00455-017-9863-6. Epub 2017 Nov 17. PMID: 29147919; PMCID: PMC5957765.|
|O’Rourke A, Morgan LB, Coss-Adame E, Morrison M, Weinberger P, Postma G. The effect of voluntary pharyngeal swallowing maneuvers on esophageal swallowing physiology. Dysphagia. 2014 Apr;29(2):262-8. doi: 10.1007/s00455-013-9505-6. Epub 2014 Jan 4. PMID: 24390651.|
|Plowman EK, Humbert IA. Elucidating inconsistencies in dysphagia diagnostics: Redefining normal. Int J Speech Lang Pathol. 2018 Jun;20(3):310-317. doi: 10.1080/17549507.2018.1461931. Epub 2018 May 3. PMID: 29724130.|
|Rangarathnam B, McCullough GH. Utility of a Clinical Swallowing Exam for Understanding Swallowing Physiology. Dysphagia. 2016 Aug;31(4):491-7. doi: 10.1007/s00455-016-9702-1. Epub 2016 Mar 12. PMID: 26970759.|
|Steele CM, Peladeau-Pigeon M, Barbon CAE, Guida BT, Namasivayam-MacDonald AM, Nascimento WV, Smaoui S, Tapson MS, Valenzano TJ, Waito AA, Wolkin TS. Reference Values for Healthy Swallowing Across the Range From Thin to Extremely Thick Liquids. J Speech Lang Hear Res. 2019 May 21;62(5):1338-1363. doi: 10.1044/2019_JSLHR-S-18-0448. PMID: 31021676; PMCID: PMC6808317.|
|van der Bilt A, Engelen L, Pereira LJ, van der Glas HW, Abbink JH. Oral physiology and mastication. Physiol Behav. 2006 Aug 30;89(1):22-7. doi: 10.1016/j.physbeh.2006.01.025. Epub 2006 Mar 29. PMID: 16564557.|
|Vose A, Humbert I. “Hidden in Plain Sight”: A Descriptive Review of Laryngeal Vestibule Closure. Dysphagia. 2019 Jun;34(3):281-289. doi: 10.1007/s00455-018-9928-1. Epub 2018 Jul 30. PMID: 30062547; PMCID: PMC6408979.|
|Vose AK, Kesneck S, Sunday K, Plowman E, Humbert I. A Survey of Clinician Decision Making When Identifying Swallowing Impairments and Determining Treatment. J Speech Lang Hear Res. 2018 Nov 8;61(11):2735-2756. doi: 10.1044/2018_JSLHR-S-17-0212. PMID: 30458527; PMCID: PMC7242916.|
Table 2. Exercise Articles
|Ashford J, McCabe D, Wheeler-Hegland K, Frymark T, Mullen R, Musson N, Schooling T, Hammond CS. Evidence-based systematic review: Oropharyngeal dysphagia behavioral treatments. Part III–impact of dysphagia treatments on populations with neurological disorders. J Rehabil Res Dev. 2009;46(2):195-204. PMID: 19533533.|
|Brody LT. Effective therapeutic exercise prescription: the right exercise at the right dose. J Hand Ther. 2012 Apr-Jun;25(2):220-31; quiz 232. doi: 10.1016/j.jht.2011.09.009. Epub 2011 Dec 31. PMID: 22212491.|
|Burkhead LM. Sapienza CM, Rosenbek JC. Strength-training exercise in dysphagia rehabilitation: principles, procedures, and directions for future research. Dysphagia. 2007 Jul;22(3):251-65. doi: 10.1007/s00455-006-9074-z. Epub 2007 Apr 25. PMID: 17457549.|
|Burkhead, LM. Exercise-based dysphagia rehabilitation: Past, present, and future.Perspectives on Swallowing and Swallowing Disorders (Dysphagia) 2017 Vol. 2 Issue 13 Pages 36-42|
|Burkhead, LM. Applications of exercise science in dysphagia rehabilitation. Perspectives on Swallowing and Swallowing Disorders (Dysphagia) 2009 Vol. 18 Issue 2 Pages 43-48|
|Carnaby GD, Harenberg L. What is “usual care” in dysphagia rehabilitation: a survey of USA dysphagia practice patterns. Dysphagia. 2013 Dec;28(4):567-74. doi: 10.1007/s00455-013-9467-8. Epub 2013 May 14. PMID: 23670700.|
|Clark HM, O’Brien K, Calleja A, Corrie SN. Effects of directional exercise on lingual strength. J Speech Lang Hear Res. 2009 Aug;52(4):1034-47. doi: 10.1044/1092-4388(2009/08-0062). PMID: 19641080.|
|Crary MA, Carnaby GD, LaGorio LA, Carvajal PJ. Functional and physiological outcomes from an exercise-based dysphagia therapy: a pilot investigation of the McNeill Dysphagia Therapy Program. Arch Phys Med Rehabil. 2012 Jul;93(7):1173-8. doi: 10.1016/j.apmr.2011.11.008. Epub 2012 Feb 25. PMID: 22365489.|
|Duncan S, McAuley DF, Walshe M, McGaughey J, Anand R, Fallis R, Blackwood B. Interventions for oropharyngeal dysphagia in acute and critical care: a systematic review and meta-analysis. Intensive Care Med. 2020 Jul;46(7):1326-1338. doi: 10.1007/s00134-020-06126-y. Epub 2020 Jun 8. PMID: 32514597; PMCID: PMC7334257.|
|Garber CE, Blissmer B, Deschenes MR, Franklin BA, Lamonte MJ, Lee IM, Nieman DC, Swain DP; American College of Sports Medicine. American College of Sports Medicine position stand. Quantity and quality of exercise for developing and maintaining cardiorespiratory, musculoskeletal, and neuromotor fitness in apparently healthy adults: guidance for prescribing exercise. Med Sci Sports Exerc. 2011 Jul;43(7):1334-59. doi: 10.1249/MSS.0b013e318213fefb. PMID: 21694556.|
|Kays S, Robbins J. Effects of sensorimotor exercise on swallowing outcomes relative to age and age-related disease. Semin Speech Lang. 2006 Nov;27(4):245-59. doi: 10.1055/s-2006-955115. PMID: 17117351.|
|Kraemer WJ, Ratamess NA. Fundamentals of resistance training: progression and exercise prescription. Med Sci Sports Exerc. 2004 Apr;36(4):674-88. doi: 10.1249/01.mss.0000121945.36635.61. PMID: 15064596.|
|Krekeler BN, Rowe LM, Connor NP. Dose in Exercise-Based Dysphagia Therapies: A Scoping Review. Dysphagia. 2021 Feb;36(1):1-32. doi: 10.1007/s00455-020-10104-3. Epub 2020 Mar 5. PMID: 32140905; PMCID: PMC7483259.|
|Langmore SE, Pisegna JM. Efficacy of exercises to rehabilitate dysphagia: A critique of the literature. Int J Speech Lang Pathol. 2015 Jun;17(3):222-9. doi: 10.3109/17549507.2015.1024171. Epub 2015 Mar 31. PMID: 25825989.|
|McCurtin A, Healy C. Why do clinicians choose the therapies and techniques they do? Exploring clinical decision-making via treatment selections in dysphagia practice. Int J Speech Lang Pathol. 2017 Feb;19(1):69-76. doi: 10.3109/17549507.2016.1159333. Epub 2016 Apr 7. PMID: 27063701.|
Table 3. Neuroplasticity Articles
|Carey L, Walsh A, Adikari A, Goodin P, Alahakoon D, De Silva D, Ong KL, Nilsson M, Boyd L. Finding the Intersection of Neuroplasticity, Stroke Recovery, and Learning: Scope and Contributions to Stroke Rehabilitation. Neural Plast. 2019 May 2;2019:5232374. doi: 10.1155/2019/5232374. PMID: 31191637; PMCID: PMC6525913.|
|Cramer SC, Sur M, Dobkin BH, O’Brien C, Sanger TD, Trojanowski JQ, Rumsey JM, Hicks R, Cameron J, Chen D, Chen WG, Cohen LG, deCharms C, Duffy CJ, Eden GF, Fetz EE, Filart R, Freund M, Grant SJ, Haber S, Kalivas PW, Kolb B, Kramer AF, Lynch M, Mayberg HS, McQuillen PS, Nitkin R, Pascual-Leone A, Reuter-Lorenz P, Schiff N, Sharma A, Shekim L, Stryker M, Sullivan EV, Vinogradov S. Harnessing neuroplasticity for clinical applications. Brain. 2011 Jun;134(Pt 6):1591-609. doi: 10.1093/brain/awr039. Epub 2011 Apr 10. PMID: 21482550; PMCID: PMC3102236.|
|Fuchs E, Flügge G. Adult neuroplasticity: more than 40 years of research. Neural Plast. 2014;2014:541870. doi: 10.1155/2014/541870. Epub 2014 May 4. PMID: 24883212; PMCID: PMC4026979.|
|Gonzalez Rothi LJ, Musson N, Rosenbek JC, Sapienza CM. Neuroplasticity and rehabilitation research for speech, language, and swallowing disorders. J Speech Lang Hear Res. 2008 Feb;51(1):S222-4. doi: 10.1044/1092-4388(2008/017). PMID: 18230847.|
|Kleim JA, Jones TA. Principles of experience-dependent neural plasticity: implications for rehabilitation after brain damage. J Speech Lang Hear Res. 2008 Feb;51(1):S225-39. doi: 10.1044/1092-4388(2008/018). PMID: 18230848.|
|Kleim JA. Neural plasticity and neurorehabilitation: teaching the new brain old tricks. J Commun Disord. 2011 Sep-Oct;44(5):521-8. doi: 10.1016/j.jcomdis.2011.04.006. Epub 2011 Apr 30. PMID: 21600589.|
|Malandraki GA, Johnson S, Robbins J. Functional MRI of swallowing: from neurophysiology to neuroplasticity. Head Neck. 2011 Oct;33 Suppl 1(0 1):S14-20. doi: 10.1002/hed.21903. Epub 2011 Sep 7. PMID: 21901779; PMCID: PMC3747973.|
|Martin RE. Neuroplasticity and swallowing. Dysphagia. 2009 Jun;24(2):218-29. doi: 10.1007/s00455-008-9193-9. Epub 2009 Jan 7. PMID: 19130130.|
|Nahum M, Lee H, Merzenich MM. Principles of neuroplasticity-based rehabilitation. Prog Brain Res. 2013;207:141-71. doi: 10.1016/B978-0-444-63327-9.00009-6. PMID: 24309254.|
|Robbins J, Butler SG, Daniels SK, Diez Gross R, Langmore S, Lazarus CL, Martin-Harris B, McCabe D, Musson N, Rosenbek J. Swallowing and dysphagia rehabilitation: translating principles of neural plasticity into clinically oriented evidence. J Speech Lang Hear Res. 2008 Feb;51(1):S276-300. doi: 10.1044/1092-4388(2008/021). PMID: 18230851.|
|Zimmerman E, Carnaby G, Lazarus CL, Malandraki GA. Motor Learning, Neuroplasticity, and Strength and Skill Training: Moving From Compensation to Retraining in Behavioral Management of Dysphagia. Am J Speech Lang Pathol. 2020 Jul 10;29(2S):1065-1077. doi: 10.1044/2019_AJSLP-19-00088. Epub 2020 Jul 10. PMID: 32650656.|
Table 4. Motor Learning
|Athukorala, R.P., R.D. Jones, O. Sella, and M.L. Huckabee, Skill training for swallowing rehabilitation in patients with Parkinson’s disease. Arch Phys Med Rehabil, 2014. 95(7): p. 1374-82.|
|Guadagnoli MA, Lee TD. Challenge point: a framework for conceptualizing the effects of various practice conditions in motor learning. J Mot Behav. 2004 Jun;36(2):212-24. doi: 10.3200/JMBR.36.2.212-224. PMID: 15130871.|
|Huckabee, M., & Macrae, P., Rethinking rehab: Skill-based training for swallowing impairment. 2014, SIG 13 Perspectives on Swallowing and Swallowing Disorders (Dysphagia),. p. 46-53.|
|Humbert IA, Christopherson H, Lokhande A, German R, Gonzalez-Fernandez M, Celnik P. Human hyolaryngeal movements show adaptive motor learning during swallowing. Dysphagia. 2013 Jun;28(2):139-45. doi: 10.1007/s00455-012-9422-0. Epub 2012 Aug 29. PMID: 22926828; PMCID: PMC3530020.|
|Humbert IA, German RZ. New directions for understanding neural control in swallowing: the potential and promise of motor learning. Dysphagia. 2013 Mar;28(1):1-10. doi: 10.1007/s00455-012-9432-y. Epub 2012 Nov 30. PMID: 23192633; PMCID: PMC3895459.|
|Krakauer JW. Motor learning: its relevance to stroke recovery and neurorehabilitation. Curr Opin Neurol. 2006 Feb;19(1):84-90. doi: 10.1097/01.wco.0000200544.29915.cc. PMID: 16415682.|
|Luft AR, Buitrago MM. Stages of motor skill learning. Mol Neurobiol. 2005 Dec;32(3):205-16. doi: 10.1385/MN:32:3:205. PMID: 16385137.|
|Maas E, Robin DA, Austermann Hula SN, Freedman SE, Wulf G, Ballard KJ, Schmidt RA. Principles of motor learning in treatment of motor speech disorders. Am J Speech Lang Pathol. 2008 Aug;17(3):277-98. doi: 10.1044/1058-0360(2008/025). PMID: 18663111.|
|Nieuwboer A, Rochester L, Müncks L, Swinnen SP. Motor learning in Parkinson’s disease: limitations and potential for rehabilitation. Parkinsonism Relat Disord. 2009 Dec;15 Suppl 3:S53-8. doi: 10.1016/S1353-8020(09)70781-3. PMID: 20083008.|
|Wulf G, Chiviacowsky S, Schiller E, Avila LT. Frequent external-focus feedback enhances motor learning. Front Psychol. 2010 Nov 11;1:190. doi: 10.3389/fpsyg.2010.00190. PMID: 21833250; PMCID: PMC3153799.|
|Wulf G, Shea CH, Matschiner S. Frequent feedback enhances complex motor skill learning. J Mot Behav. 1998 Jun;30(2):180-92. doi: 10.1080/00222899809601335. PMID: 20037033.|