This text-based course is a transcript of the webinar, “Cranial Nerves and Dysphagia: Making the Connection,” presented by Tiffani Wallace, M.A., CCC-SLP, BCS-S.
>> Tiffani Wallace: I used to be extremely scared of cranial nerves because they did not make sense to me. A couple of years ago, I decided that I wanted to get my board certification in swallowing and swallowing disorders. In doing so, after completing the application process, you must take and pass an exam. They do not tell you what is on this exam, but in talking to a few people and trying to prepare to study, everyone told me to make sure to know the cranial nerves. As I have studied these cranial nerves and learned what they do, I have incorporated these more and more into my swallowing assessments with my patients. It not only gives me a better idea of what I am seeing with my patients, but it gives me a better idea of how to create a more effective treatment program for them.
How many of you currently use cranial nerve assessments in your swallowing exams. I am finding that most people do not use cranial nerve exams. What is happening is that we are assessing the cranial nerves, but we are not calling it a cranial nerve exam.
Terminology
When we look at cranial nerves, there is some terminology that we all need to know. The central nervous system (CNS) is imperative in our knowledge related to dysphagia. The central nervous system is the brain and the spinal cord. The brain is where all of the cranial nerves are housed, mostly in the brainstem. Sensory information is received and motor information is sent through the peripheral nervous system, which is made up of the cranial nerves, the spinal nerves, and any of those autonomic functions such as our parasympathetic fibers, which are responsible for salivation.
When we look at sensory versus motor, you may see the terms afferent and efferent impulses. Afferent is sensory, and is any of the information that we take from the bolus, which could be the temperature, the taste, the size, and the texture. That information goes to the brain, which then sends a message back to the muscles through the efferent, or motor, response. Efferent is an impulse from the brain going to the muscles or the glands.
We always talk about lower motor neurons (LMN) and lower motor neuron deficits, which relate to the extremities. They are closer to the actual muscles, and closer to those extremities. The upper motor neurons (UMN) are the corticospinal tract, which is your brain, brainstem, and spinal cord. When we see upper motor neuron paralysis, we see more spasticity, while a lower motor neuron paralysis is more often the flaccid type.
