The Neck and Parkinson's Disease, Part 1

A BOTTLE NECK TO NEUROLOGICAL HEALTH

I have noticed that a lot of (most) people with Parkinson’s Disease, and other neurological disorders too, such as Alzheimer’s, suffer with severe neck pain and/or stiff, rigid necks. In terms of neurological problems, our necks can be a pinch point - a constricted passageway or tunnel, through which all the superhighways between our brain and the rest of our nervous system and organs, and from there, out into the far reaches of our fingers and toes, must pass. All of our “utilities”, the two-way electrical wirings, the broadband and telegraph wires of the nervous system, the water and air supplies, the chemical pipelines providing nutrients and the sewer pipes taking away the excreta of the brain, must pass through this narrow gap. This is no ordinary tunnel: to keep these utility supplies open and running, it was designed to keep on moving itself – and in truly extraordinary ways of flexible motions.

Even slight damage or stiffening up of the neck can cause constrictions or interruptions of these important electrical and chemical flows. For oxygen and nutrients that enter through the mouth or nose, it is double jeopardy, as they have to pass through the bottle-neck twice, down into the lungs or to the gut, and back up again to get the brain. The neck is therefore a primary attention site for progressive symptom reduction strategies. In this article, we look at aspects of the neck and consider what we can do to improve our lot.

The Preponderance of Injury in the Past of People with PD

Neck issues or damage can be caused by injuries, but the injury site doesn’t have to be local to the neck itself, since it is an integral part of the kinetic chain of the human body - problems anywhere else which affect posture can, in turn, profoundly affect how we tense our necks and cause strains on it by the way we are holding up the head. I’ve frequently asked people with Parkinson’s Disease to think carefully about any pains and injuries which they might have incurred either before or concurrent with their PD diagnosis. I’ve found that the overwhelming majority of us have suffered a prior accident or physical trauma. Injuries to jaw, neck, shoulders, back, hips, knees or feet predominate. All these severely affect posture and hence the kinetic chain and are liable to make our necks prone to permanent strains and stiffness. So in my view, even if chemical “cures” were invented tomorrow, people with PD would still present with the postural problems, still suffer from the old injuries which have been masked by the narratives of neurology, and would probably quickly decline into pain and problems again, unless these past injuries are properly attended to.

Some Relevant Structures of the Neck

Muscles and Fascia

The above image of a cross-section of the neck shows just how many muscle groups are involved in the complex movements the neck is capable of. Many people with PD suffer dystonia in some of these muscles: abnormal muscles tensions, which can be very painful and cause the neck to feel stiff or rigid and the head to be locked in certain positions.

A great source of information on dystonia comes from Dr. Joaquin Farias, who has developed an online dystonia recovery program. In his introduction to his neck neuro-exercise course aimed at reducing symptoms of cervical (neck) dystonia, Dr Farias goes through every possible type of neck dystonia from a very basic starting point. As part of this, he explains which muscles are either hypertense (overcompensating) and hypotense (forgotten), resulting in a person’s head being stuck in a specific position. Possibilities include head and neck twisting (torticollis), or the head being pulled forwards (antecollis), backwards (retrocollis), or sideways (laterocollis), and he also coverts how these basic types can combine into more complex appearing manifestations. For the position which best describes myself (retrocollis), Dr Farias points to a set of muscles which I'd never heard of (in my naivety, I always assumed the problem was my right scalene muscle area). Looking up the specific muscles he mentions, called the splenius cervicis, this was a bit of a “lightbulb moment” for me, because these muscles does seem to describe very closely the line and points where I feel my pain and stiffness the most in my neck. I therefore believe that becoming familiar with the muscles of the neck, and those which may have become dystonic, is a helpful starting point.

The image above also shows there is a lot of fascia in the neck, e.g. the blue lines in the picture denotes this visco-elastic collagen based connective tissue that surrounds and separates the muscles, nerves and bones. I have previously written about the vital role that fascia and fascial problems play in PD. Hence the abundance of fascial layers in the neck provides a lot of scope for problems to arise, and combine in vicious circles with stiffness and lack of mobility.

In particular for PD, the "carotid sheath" [shown as red in the image] seems a really important area to consider - this fascial layer surrounds and contains a number of very important structures, including the vagus nerve as it passes through the neck, the carotid artery and jugular vein and lymph nodes too. Problems such as dehydration, stiffening or tightening, damage or inflammation of the fascia of the carotid sheath might be causal of vagus nerve dysregulation (pinching?), blood and oxygen supply issues, immune responses and poor lymph drainage of the brain, all leading to neurological symptoms. Indeed, ultrasound studies have shown that the vagus nerve as it passes through the neck is atrophied (smaller cross-sectional area than normal) in people with PD, while poor oxygen supply to the brain has also been implicated.

Nerves and Nervous System

The vagus nerve is not the only important nerve which passes through the neck. According to the polyvagal research of Dr Stephen Porges, five of the cranial nerves form the parasympathetic “ventral vagus complex”, responsible for Social Engagement functions. Interestingly, this vagal complex includes the accessory nerve, that innervates the neck muscles used to turn the head. In his early paper on polyvagal theory, Dr Porges writes:

"Thus, more specialized functions such as head rotation to orient sensory receptors toward the source of stimulation, mastication to ingest food, and salivation to initiate gustatory and digestive processes are integrated into the vagal system."

"In mammals, the part of the brain where these nerves originate controls the complex coordination of pharynx, soft palate, larynx, and esophagus. Of special note to psychophysiological processes… the carotid body, containing peripheral chemosensitive receptors sensitive to oxygen and carbon dioxide levels…"

[We will return to the carotid bodies, and their importance, below].

"In addition, the accessory nerve provides fibers originating in the cervical spinal cord that innervate the positioning of the neck. The critical carotid arteries, internal jugular veins, and vagus nerves run deep in these muscles."

"Thus, this complex also has the ability to orient visceral receptors via somatic muscles [to turn the head to listen or look at potential threats or just to get ones bearings], to coordinate structures related to ingestion and expulsion, and to regulate facial expression and emotion."

The functions of this ventral vagus complex seems to be offline or atrophied in people with PD, who tend to have problems with eyes, swallowing, saliva, speaking, hearing, facial expression, but also significant problems with turning/moving the head due to downregulation of the accessory nerve function.

Sensors

The neck contains special mechanoreceptors and chemoreceptors which detect and help regulate blood pressure and blood oxygen levels, respectively. These seem highly pertinent to PD, as issues with blood pressure and breathing are common with the condition.

“Baroreceptors are a type of mechanoreceptor allowing for the relay of information about blood pressure within the autonomic nervous system. Information is passed in rapid sequence to maintain blood pressure within a preset, normalized range. Arterial baroreceptors include those located within the carotid sinuses in the neck. Arterial baroreceptors function to inform the autonomic nervous system to changes in blood pressure within the arterial system. Rapid decreases in blood pressure, such as in times of orthostatic hypertension result in decreased stretching of the artery wall which ultimately results in the baroreceptors causing an increase in blood pressure. The opposite is found to be true of increased blood pressure."

It also seems that well-functioning baroreceptors have a role in dampening pain and stress responses:

“When the baroreceptors located in the carotid body are stimulated by the cardiac cycle, in particular during the systolic phase [when the heart is contracting], the nociceptive stimulus [relating to the sensation or perception of pain] is attenuated by the activation of baroreceptors. The baroreceptors’ activity also affects muscle tone, as it decreases the activity of the sympathetic nervous system, reducing the contractile state."

Since pain and abnormal muscle rigidity are common features in PD, one wonders if baroreceptor dysfunction may be playing a role. Conversely, when there is issues with rigidity and stiffness in the muscles and fascia of this area on the neck itself, as is often the case with PD, could the resulting compressions/restrictions cause the baroreceptors to malfunction? This seems like a reasonable conclusion when we learn that the baroreceptors and their feedback to the nervous system is indeed sensitive to imposed pressures and forces. Actually, there is a very interesting connection here with the affects of weather on the symptoms of PD. Some time ago, I looked into the the science behind how weather, and air pressure in particular, really does have profound effects on symptoms of chronic conditions, as many of us with such issues will anecdotally already know. However, a scientific journal article goes further and finds relatively small oscillations or fluctuations in air pressure can have an impact too, through the baroreceptors mainly in the neck:

"Our basic idea is that the baroreceptors of the blood pressure control system are not indifferent to changes in external air pressure. The ambient air presses immediately two carotid sinuses located symmetrically just underneath the skin of the neck... variations in the external air pressure sway the reference point of the baroreceptors, thereby feeding a false signal into the baroreflex loop... changes in peripheral resistance and corresponding changes in arterial pressure and cardiac output [and nervous system states] under exposure to [air pressure oscillations] may result..."

Furthermore, there are known medical issues with pressure on the carotid sinus:

"...carotid sinus syndrome … in which the carotid sinus is particularly sensitive to external pressure. Increased pressure on the carotid sinus, such as from a particularly tight collar or sustained turn of the head, results in significant hypotension and possibly syncope [fainting, passing out]. Carotid sinus sensitivity can result in syncope with stimulation of the carotid sinus externally, such as with shaving."

Also,

"Stimulation of the carotid sinus via a slap or a strike, to induce (usually temporary, but sometimes lethal) loss of consciousness is a theatrical self-defense technique, and is often taught in martial arts such as karate."

For me, this leaves open questions about the impacts of tight muscles and fascia in the area of the neck containing the baroreceptors in the neurology and physiology of PD.

There are also important chemical sensors (chemoreceptors) in the neck which are part of autonomic breathing function, in a structure called the "carotid body", a small cluster of chemoreceptor cells located in the bifurcation (fork) of the common carotid artery, which detects changes of the partial pressure of arterial oxygen, and also of carbon dioxide. The carotid bodies can influence breathing by releasing a variety of neurotransmitters, including acetylcholine and dopamine.

At this point, I hope this is enough to pique the interest of many people with PD in the potential role of these chemical sensors in the neck. given that dopamine is the very neurotransmitter we are short of, and also because most of us have very poor breathing habits - fast and shallow chest breathing through the mouth. In fact, I found so much pertinent information about the carotid bodies that there is enough material for a follow up article dedicated to this, see Part 2. For now the relevant question is again how do constrictions, fascial adhesions, hypertonic muscles, etc. in the neck, impact the carotid bodies, and hence affect breathing?

What Can We Do?

It would seem to me that there are a number of very vicious circles and negative feedback loops between neck stiffness/rigidity/pain and neck immobilization and posture in PD, which not only impact on each other, but also have neurological and physiological implications much more broadly, including on nervous system, blood pressure and breathing. The principal strategy for progressive symptom reduction would therefore be to increase and maintain mobilization of the neck and to improve posture as much as possible, through daily exercises and therapies, and to address any old injuries elsewhere on the body which may be impacting on posture and hence neck strain.

Dr Farias provides a suite of daily exercises which help to reduce these type of neck problems over time, especially designed for, and tailored to the different types of, cervical dystonia. Many people around the world report that doing his exercise classes daily reduces the symptoms and pain of their neck dystonia, and can eventually even lead to a full recovery. This works through a process of neuroplasticity, which re-wires the connections between the muscles and the brain through movement therapy.

Although at first one might feel that the neck has become so stiff, it can’t move it all, even starting with micromovements or just thinking about moving the head, can be enough to gradually increase range of movement. A useful "trick" I found is to imagine drawing a figure of eight with the chin. I tried this and found it was much easier to move my head when thinking about it this way. Even when my neck is very rigid and stiff during an "off" period, I find although my chin barely moves, it does make micromovements and I can feel the muscles of my neck/shoulder at least twitch (engage/disengage), so this helps to get mobilization started. I've found many variations on this theme which can help: imagine drawing the figure of eight with the nose instead, and then with the forehead/third eye point - that one makes me a bit dizzy which means my vestibular system is being engaged, which is a good thing usually. Or try drawing different shapes such as circles with chin, nose or third eye point. More random motions can be achieved by trying to sign your name with your chin, say.

As well as the muscles per se, it is likely that the fascia health of the neck will also need attention. I have personally been using a modality called Block Therapy which uses a specially designed block of wood to apply pressure to various parts of the body for fascial decompression. I have been blocking my sternum, clavice, pectoral, shoulder and neck regions, for a total of fifteen minutes daily since about Christmas 2019. I have seen profound changes in this time, as shown in the month-by-month photo record below.

In particular, my shoulders have dropped massively, my neck has lengthened, and my forward head position has been largely rectified, all helping to improve my posture enormously. I was made aware that this effect is noticeable when someone asked me if I was getting taller! However, the main benefit of attending to my neck fascia is the improvement of quality of life I’ve experienced through the reduction of my discomfort and suffering. The major pain and rigidity that I experienced in my right neck and shoulder whenever the PD drugs wear off (several times a day), and which remained by far my most debilitating symptom, has very significantly reduced over the time I’ve been using Block Therapy.

As well as “self-care” therapies, there are now many manual or bodywork therapists, who use one or more modalities designed to release fascia, who could be very helpful with frequent and regular visits. Michael Hamm of the Neurofascial Approach provides an insight in the potential benefits which may be gleaned with a trained and knowledgeable fascia therapist:

“Additionally, that carotid sheath connects in the middle to the Alar Fascia (seen as that blue line just above the spine in the above cross-sectional image of the neck)… If in a calm ritual space, one uses a gentle pincer grip to draw the sternocleidomastoid muscle belly directly out away from the center line of the neck, the carotid sheath will be drawn out as well on the sternocleidomastoid underside. This is how I (intend, at least, to) give an outward stretch to the ansa cervicalis, and engagement of alar fascia. Quite often, if this is done gently, one will hear a belly growl or other signs of elevated Vagal motor output.”