Introduction
Some time ago, I proposed that Idiopathic Parkinson’s Disease is the result of the nervous system becoming stuck in the Freeze or Death Feigning stress response. This provides a single framework that explains all the motor and non-motor aspects of the condition. However, my use of the term “freeze” sometimes causes confusion, because it is ambiguous due to different people using the same term to describe quite different aspects of nervous system responses. Therefore, the nature of the state which I am referring as the “stuck state” in PD is in need of some clarification.
Fortunately, more recently I discovered and read an excellent article,
Dissociation Following Traumatic Stress: Etiology and Treatment,
which very clearly and carefully demarcates the different immobilization programs of the nervous system. Therefore, here we will consider this article in detail, and in particular use it to clarify that the immobilization response relevant to PD is the state called “tonic immobility”.
Becoming stuck due to traumatic stress
The major thrust of the above mentioned article is that immobilization and dissociation effects, which are seen as symptoms in post-traumatic stress disorders, and inferred by myself to also be apparent in the symptoms of PD, are first seen during traumatic events, when they are adaptive for keeping us alive. In particular, these first occur when we encounter a threat which is potentially lethal, imminent, and proximate. However, these responses can then recur latter as a symptom when the fear response is triggered and the threat is recapitulated.
The initial adaptive nature of immobilization and dissociation has often been missed. These enable survival during a direct and very close encounter with a dangerous perpetrator/predator, or when bodily integrity is already compromised, for example by invasion or penetration of sharp objects such as teeth or a knife.
To survive these situations requires physiological adaptations, including immobility, pain tolerance and changes in consciousness, senses and behaviour, which may seen as odd to others, since they are outside of every day experience.
The authors’ model therefore includes three stages of stress response beyond the usual Flight, Fight and Freeze: Fright, Flag and Faint.
The Orienting Response as Freeze
In the authors’ framework, a stress or threat response starts with a first stage they call “Freeze“, “Attentive Immobility” or the “Orienting Response (OR)". They propose that “Freeze” should strictly be reserved to this part of the response only. As we will see, this type of freeze is not the immobilization mode people with PD are stuck in.
The OR is a transient stage, preliminary to fighting or fleeing, in which the person stops moving to avoid detection by predators or perpetrators, and to focus the senses and cognitive resources on gathering information on the source of possible danger, and on a plan of action. An example of this is the case where a deer hears a noise in the distance, raise its head and stands very still, with its ear orienting towards the sound. The OR is sometimes referred to as hypervigilance or hyperarousal, and involves being on guard, watchful, alert, and ready to respond. This type of freeze occurs when the threat is still at a distance.
Tonic Immobility or Unresponsive Immobility
Subsequent to all fight and flight options having been exhausted, such that the threat is now very proximate and inescapable, the next option in the cascade is another immobilization response that the authors’ refer to as “Fright” or “Tonic Immobility”, the purpose of which is
“inhibition of aggression through muscle restraining when being overwhelmed by threat".
Here, I will make the case that it is this fright stage of the stress response which people with Idiopathic Parkinson's Disease are chronically stuck in.
According to the article:
"Fright can be understood as the turning point at which... the imminent [shutdown] stage is characterized by co-activation of the sympathetic and parasympathetic system. The high dual autonomic tone is known as a risk for sudden cardiac death.”
"The heightened muscle tonus [of fight or flight], which enables better action performance, causes the muscles to be overly tense beyond a certain threshold, as well as rigid, and movements to become slow and difficult. At this stage overt behavioural actions are not an option; skeletal muscles tense to a stage of tonic immobility."
Note that stiff and rig\id muscles, and fascia, and slow difficult movement, or “bradykinesia”, are also classic signs and symptoms of PD.
"Tonic immobility has also been used to describe the paralysis, which often immobilizes animals such as rodents or birds and a similar state is known from invertebrates when they feel threatened by a predator. The immobility of the organism during the fright stage reminds the observer of spastic paralysis. It looks as if the organism is ‘‘frozen like ice’’ (temporary gross motor inhibition) because of the stiffness involved."
Below is a video showing animals in tonic immobility states (8 minutes into the film):
"In tonic immobility, the organism is emotionally aroused and full of fear, yet unresponsive to even painful stimulation and the posture, which may be held for long periods of time, often appears bizarre."
Fear, terror, high anxiety, and panic, and pronounced postural issues are also part and parcel of the symptomatic state in PD. It is also often very painful, with all the different forms of dystonia being common, while, at the same time, other parts of the body can feel numb.
"The organism appears dead or unresponsive to exteroceptive stimuli, internally the animal is highly alert. This unresponsive immobility is elicited most easily during intense fear and some form of physical restraint or perception of entrapment."
Indeed, PD is much more of a "locked in" situation rather than an out-of-body experience - internal sensations are all consuming of attention.
"Tonic immobility or ‘thanatosis’ is a process by which mammals feign death in order to evade unwelcome attention. Such catatonia can be understood as an evolutionary-based fear response, with features such as immobility, decreased vocalization, analgesia, ‘‘waxy flexibility’’ [a condition in which a patient's limbs retain any position into which they are manipulated by another person] and evidence of alertness as well as the fixed eye gaze, reducing visual input from the offender and thereby decreasing distress and arousal.
Decreased vocalization, this "waxy flexibility" phenomena and fixed eye gaze are all classical signs of PD too. Indeed, when very symptomatic, people with PD can become so stiff that they can be manipulated into different positions like an action figure, and they will stay frozen in that position. I experienced the waxy flexibility very profoundly when I was under a great deal stress and ended up in hospital. One of the doctors described my state as “catatonic”.
"Thus, the core catatonic[!] symptoms of stupor, mutism, and immobility are directly linked to tonic immobility. In the past, this was for a long time seen as a consequence of 'very severe physical or mental stress . . . [such as] a very terrifying experience'. The patient remains entirely motionless, without speaking, devoid of any will to move or react to any stimuli. The general impression conveyed by such patients is one of profound mental anguish or an immobility induced by severe mental shock. All in all, these patients give the impression of the deepest mental pain, of being paralyzed after a great fright."
According to Dr Joaquin Farias, PD is a form of generalized dystonia, which results from a shock to the pre-frontal cortex.
"The lack of movement in unresponsive immobility has a fast on and off switch, but can last from a few seconds to many hours."
People with PD can freeze very suddenly, e.g. when walking through doorways or when touched (which perhaps does point to the proximity factor being at play), but can also unfreeze again suddenly, e.g. due to music. After several years of medication via l-dopa supplementation, people with PD begin to switch "on" suddenly as a dose begins to kick in and switch "off" suddenly as it wears off.
"Inability to move, inability to call out or scream, no loss of consciousness/recall of details of the attack, apparent analgesia, that is, numbness and insensitivity to pain. The researchers noted as well a sensation of feeling cold and shivering. We assign the feeling of cold and trembling to the consequences of adrenaline and vasodilatation whereby body warmth is lost fast and leads to shivering (medical ‘‘shock’’).
Tremor and cold extremities are also classic signs and symptoms of PD.
Flag and Faint
The article also covers one more form of immobilization response, which again does not generally correspond to PD, because in this case the muscles are flaccid, but could be of relevance to advanced PD in which the person cannot stand up without falling over, and appears more “vacant”.
The tonic immobility state, corresponding to PD, described above, puts lots of strain on the system, and so it is dangerous to maintain for long. This may be why PD tends to be such a degenerative, deteriorating condition. Thus the authors propose that the defence cascade finally completes with a total shutdown as a last ditch effort to preserve life. They label this stage “flag and faint” or “Flaccid Immobility”.
In this model, fainting, or “vasovagal syncope”, is a last resort to guard against the danger of cardiac failure and to reduce oxygen consumption where cardiac strain is excessive due to prolonged tonic immobility. A horizontal position also restores blood supply to the brain
Flaccid immobility is less of a “switch” than tonic immobility, with slower transitions in and out. The muscle stiffening in tonic immobility changes to flaccidity. Language fails, the mouth may fall open, but there is no vocal sound. The posture slumps. Dissociation occurs, in which the senses become dulled, and body awareness and pain disappears, and numbness prevails. Consciousness and emotions fade away.
How and Why We Get Stuck
Whenever we encounter a sufficiently traumatic event or experience, such that the stress response includes the tonic immobility stage, our nervous system becomes familiarized with these states, and also becomes more sensitive to threats. This generates triggers or trauma reminders that can recapitulate the stress response at any time. If we encounter such events routinely, our nervous system becomes more and more sensitized, and hence more easily triggered, and begins to react by going directly into tonic immobility at the first sign of danger. With enough of a cumulative effect, the nervous system begins to sense danger everywhere and the threat response gets stuck permanently on. This doesn’t necessarily require major life-changing traumatic events, but possibly even daily micro-traumas of the right kind can add up.
The article explains the types of traumatic events from our ancestral heritage which can trigger tonic immobility:
"Tonic immobility is almost always displayed when the person is overwhelmed by threat and not allowed and not able to act aggressively against the threat. Thus immobility functions to supress anger and acts bidirectionally to inhibit aggression in a number of ways.
So it is a response which kicks in when there are no escape options, where we can't run away and we can't fight the threat, or fighting it would increases our chances of incurring lethal injury.
"1. ‘Submission’ after other strategies (like escaping, screaming, and fighting back) have failed in order to stop aggression: for example, a toddler shows a fright reaction as the adult displays rising aggression."
"2. ‘Holding still’ to reduce risk of tissue damage: for example, sharp objects touching the surface of the skin. When the skin is contacted by sharp objects (a knife, teeth heavy movements, struggling, or pulling away with a sudden move will cause even more tissue damage and damage to mucous membranes, as well as deeper wounds."
"3. ‘Eliminating cues’ for predatory behaviour: stiffening of the voluntary muscles can occur during direct physical contact with the carnivore or the human predator. Tonic immobility increases survival chances even when physical contact has been made, because movement cues are critical releasing stimuli for predatory behaviour, and immobility eliminates these cues. Surviving through ‘motionless pretending to be dead’ has its evolutionary roots as a defence mechanism against predators. Predation tests demonstrated that prey, which struggles or moves when attacked, is killed and eaten, but if prey remains immobile, feigning death, the predator loses interest and the prey survives."
"4. ‘Escape preparedness’ in case there is a chance to resume flight: captured prey that becomes tonically immobile rather than struggling and fighting may increase its chance of escaping when the predator temporarily loosens the grip under the assumption that its prey is indeed dead. In mammals, struggling prey is only held on to until resistance subsides. It is also a response that may be adaptive in human beings when there is no possibility to escape or win a fight, and this behavior is in fact recommended by park authorities for encounters with a grizzly bear. An organism in tonic immobility is immobile but is markedly tachycardic, vasoconstricted, hyperalert, and prepared to flee in a moment of opportunity, a state that also characterizes human catatonia."
"When the aggressor approaches rapidly and comes close, the organism can for a short time again dramatically change its behaviour in that it suddenly displays an explosive escape response in conjunction with aggressive behaviour. This fact demonstrates that high aggressive arousal (anger) is inhibited at that stage but present. If these explosive responses do not eliminate contact, immobility may return, reducing the likelihood of continued attack."
It is, however, worth pondering how many threats we encounter in the modern social and cultural setting which match the description of no escape options (we can't run away from the threat), and no aggression options (fighting it would increases our chances of incurring physical or psychic or financial or relational injury).
Everyday examples may include: a child trapped in a classroom with a bad teacher; being trapped in a job with a bad boss; being trapped on a crowded train with strangers; being trapped in a traffic jam surrounded by other angry people in nearby cars; being trapped by an apprehending policeman; being trapped in an office with a doctor. The repeated or daily micro-episodes of this type of stress response due to feeling trapped may add up and eventually result in it being switched on semi-permanently.
We can also consider including internal threats into the cumulative effect, that might generate a cellular level version of “tonic immobility” (see the Cell Danger Response), from which we can’t fight or run away from either, such as chronic viral or fungal infections, pathogens in our environment, injuries and surgeries.
What Can We Do About it?
What actionable and pragmatic steps does this framework of understanding of Idiopathic PD point us to? To quote myself:
“We need to be doing everything we can to calm our Nervous Systems, Immune Systems, inflammation, stressful emotional states and anxious thoughts, to address unhealthy relationships, to restore a sense of internal and external safety, and to send the message to our biology that ‘the war is over’.”
As a first step, we perhaps need to identify the places where we are stuck in our lives, those stressors which come with a sense of being trapped, the stressful things we can’t fight or flee from, and try to address these. This is because the tonic immobilization framework of PD predicts that it will be very hard to reduce symptoms in circumstances that our nervous system is constantly feeling trapped by a proximate threat. Examples include being in a toxic relationship, living in a house with neurotoxic mould infestations, workplace exposure to a chemical agent, enduring a long and stressful daily commute to work.