Introduction
In
THE DIVIDED BRAIN AND PARKINSON'S DISEASE, PART 1,
we introduced the research of Iain McGilchrist about “the Divided Brain”, which concerns how the left and right brain hemispheres have different roles and provide us with very different perspectives and awareness of the world. There, we began to explore how over-activation of the left hemisphere and inhibition of the right could explain real world experiences of people with Parkinson’s Disease, and discussed the implications of this.
In this sequel, we examine more closely the issues that an imbalanced brain function causes, in particular when the left brain is overly dominant, and show that there are strong correlations with the major motor and non-motor symptoms and real lives of people with Parkinson’s Disease. We will also explore links to Dorsal Vagus Nerve mediated immobilization.
In each part below, we will identify particular known issues for people with PD, and see how these correspond to the facts and information about the left and right brain hemispheres from Iain McGilchrists book
THE MASTER AND HIS EMISSARY,
excerpts from which are quoted in italics. We will also seek to suggest potential therapies based on these findings in each case.
PARKINSON’S SYMPTOMS AND THE DIVIDED BRAIN
EMOTIONAL REGULATION
As people with PD, we tend to have poor control over our emotional states, as well as poor senses of our own body (the senses of proprioception and interoception). Anger management issues are common too.
Corresponding facts about the Divided Brain:
"Part of the right hemisphere is essential in emotional regulation. The right regulates the hypothalmic-pituitary axis, which is the neuroendochrine interface between the emotions and the body, essential to our appreciation of the body's physiological condition, connected with the automatic systems for regulating the body and its level of arousal, through the autonomic control of heart rate, for example. As a consequence, it is the right which also exerts inhibitory control over emotional arousal."
"The one exception [to the right being responsible for emotional states] is the expression of anger. Anger is robustly connected with the left frontal activation. Aggression is motivating and dopamine plays a crucial role in the rewards it offers".
So an inhibited right hemisphere would help explain the lack of emotional health which tends to be associated with PD. Counselling, trauma healing and psychotherapies can significantly help in this regard.
FACIAL EXPRESSION AND RECOGNIZING FACIAL EXPRESSIONS
People with PD are notoriously poor performing when it comes to recognizing the emotional states of others, through face, voice or gesture, and may find it very difficult to make eye contact. Typically we have flat, blank, expressionless or masked faces ourselves. We also tend to have monotonic voices too. An inability to smile, laugh or cry is also common.
Corresponding facts about the Divided Brain:
"It is the right hemisphere that identifies emotional expression: it is faster and more accurate than the left in discriminating facial expression and emotion. The right is also the major interpreter of prosody (vocal intonation) and gesture. Those with right brain damage have difficulty understanding emotional intonation or implication".
"Curiously, it seems that the left reads emotion by interpreting the lower part of the face. Though the left can understand emotional display, it looks not at the eyes, even when directed to do so, but at the mouth".
"The right is pre-eminent, not only in identifying an individual face, but also in interpreting its emotional expression."
"As well as emotional recognition, the right plays a vital role in emotional expression, via the face and prosody of voice. The right frontal lobe is of critical importance for the emotional expression of virtually every kind through face and body posture".
"It is the right that creates spontaneous facial expression in reaction to humour or other emotions, including smiling and laughing. It is also the right that is responsible for expressing sadness through tears".
"The left half of the face, which is controlled by the right hemisphere, is more involved in emotional expression".
So an inhibited right hemisphere also succinctly explains lack of emotion and expression, and difficulties interpreting these in others too. Suggested therapies include cranial nerve neuro-exercises, such as practising making facial expressions, speech and language therapies, singing, social engagement, laughing yoga, looking at picture cards of faces with different emotions developed for autism.
TYPES OF DEPRESSIVE STATES
According to the Iain McGilchrist book:
"Depression resulting from damage to the right has more of an indifference, apathy - a global, vague lifelessness... anxious apprehension, based on fear of uncertainty and lack of control - preoccupations of the left, is accompanied by preferential left activation".
"The perception of color in mental imagery activates the right, not the left... right is more attuned to color discrimination... the right prefers green, and the left red".
I often consider people with PD as having reduced Aliveness or Life Force, a feeling of emptiness, being exiled from life. Anxiety about uncertainty and worrying over the future (not living in the present) is a very common feature, as is the need to control everything and everyone around us, resulting in Obsessive-Compulsive disorders for example (another left brain feature). The lack of appreciation for color (and music) is also common, which often gets identified only upon healing: "colors seem more vivid" is a frequent observation of those in recovery. Walking in nature (amongst greenery) is known to be a highly beneficial therapy. Music therapy has also been shown to be very impactful on motivating movement in people with PD. Stress reduction is mandatory in living well with the condition. Eliminating foods which increase anxiety and depression is also crucial
BODY IMAGE, DISCONNECTION AND DISSOCIATION
A significant feature of people with PD is that we tend to have (severe) issues with body image, and usually feel disconnected from our bodies, as if we have become dissociated or disembodied from feedback with our sensory and motor neurons. "Hypermobility" issues, similar to those found in Postural Orthostatic Tachycardia syndrome or Ehlers-Danlos Syndrome , are very common, for example.
Corresponding facts about the Divided Brain:
"The right brain hemisphere is deeply connected to the self as 'embodied'. The left carries an image of only the contra-lateral right side of the body: when the right hemisphere is incapacitated, the left side of the body virtually ceases to exist for that person! The right lobe, however, has a whole body image, disturbances to this lobe lead to profound illnesses, such as body dysmorphia and anorexia nervosa."
"The right and left also see the body in different ways... the right is responsible for our sense of body as something in which we 'live'... for the left, the body is something from which we are relatively detached, a thing, devitalized. There is greater proprioceptive awareness in the right, where it is far more closely linked to physiological changes that occur in the body when we experience emotions."
So again, right side inhibition can explain much of the disconnection that people with PD may experience. Therapies which help to re-connect mind and body, increasing our sense of "embodiment" are found to highly beneficial for people with PD, such as yoga, dance, massage, fascia release, somatic experiencing. Clearly, one reason that the physical therapies mentioned above can be so beneficial to those of us with PD is through stimulating and nurturing the right side of our brains, thus bringing back a better left-right hemisphere balance.
MUSIC AND SOUND AVERSION
People with PD tend to have an aversion to music, and are hypersensitive to noise and sound, more generally. Furthermore, we may have a poor sense or appreciation of music, such as being "tone deaf", but also not having a good grasp of melody or beat, and not being able to hear multiple instruments and voices simultaneously.
Corresponding facts about the Divided Brain:
“Music, being grounded in the body, communicating emotion, implicit, is a natural expression of the nature of the right hemisphere... given that intonation of voice and emotional aspects of experience are its special concern, it is expected that music appreciation would be especially part of the right... we are all aware of how music affects us physically through our emotions... this process leads to physiological reactions, such as alterations in breathing, heart rate, temperature, blood pressure, even making us sweat, bringing tears to our eyes, or making our hairs stand on end... though speech is principally a left function, the production of words in song is associated with right activation... in cases of right brain damage, the perception of timbre, rhythm and complex sounds may be badly affected".
Conversely, music can be an extremely powerful form of therapy for people with PD, with particular styles, such as Mozart or lullably (prodosic) quality singing voices, and emotive music, being especially helpful. Presumably, this is because as described above, music stimulates and enlivens right sides of brains.
Yet here we face a problem. We have already covered in Part 1 how those musically trained during developmental years and professional musicians are particularly prone to PD related issues in later life: movement disorders, personality issues and chronic pain called dystonias. According to the above, however, the constant exposure to music should afford a great deal of protection from right brain inhibition and left over-activation? It turns out that exactly the opposite is true because those highly trained in it no longer have access to the unique therapeutic and right brain protective value of music. In fact, constant exposure to music can then become a significant activator of the left brain in professional musicians!
"Music raises an intriguing problem. The above applies to the amateur: the professional or highly trained musician appears to use the left to a much greater extent in understanding music... this may be a special case of a more generally applicable principle: while we are gathering new information, the right is responsible, but once whatever it is becomes thoroughly known, familiar, it is taken over by the left".
ADDICTION, GRANDIOSITY AND DENIAL
As a sweeping generalization, people with PD are susceptible to addictive and obsessive-compulsive behaviours. We may also display narcissism and arrogance, as defensive mechanisms, which the trauma literature labels "grandiosity". We can be very good at mustering arguments (especially circular ones). We are often in complete denial about our own behaviours and thought process too, and can be extremely stubborn and strongly averse to change.
Corresponding facts about the Divided Brain:
"People with frontal lobe damage, on the right in particular, are impulsive, fail to see consequences and are emotionally disengaged from others. With inactivation of the right pre-frontal cortex, we act more selfishly. The right's capacity to inhibit our natural selfishness means that it is also the area on which we rely for self-control and the power to resist temptation."
"The left tends to get stuck, its tendency to recur what it is familiar with, reinforcing whatever it is already doing, as if trapped in a hall of mirrors... the right is capable of freeing us... right-side damage is associated with addictive behaviours".
"The right is also more realistic about how it stands in relation to the world, less grandiose, more self-aware than the left. The left is ever optimistic, but unrealistic about its shortcomings. Denial is a left speciality. In states of relative right inactivation, with a bias to the left, are more apt to stick to their own points of view. The left tends to insist on its theory, at the expense of getting things wrong, and will still cheerfully insist that it got it right later. So the left needs certainty and needs to be right."
"The left draws mistaken conclusions from the limited information available to it and lays down the law about what only the right can know. However, it is the right that makes judgements about the truth or plausibility of these narratives. The left may be unreasonably, even stubbornly, convinced of its own correctness."
Suggested potential therapies to ameliorate these issues include mindfulness, self-awareness, cognitive behaviour therapy, mediation.
Summary
There appears to be considerable overlap between left-brain dominant/right-brain inhibited issues and those of Parkinson’s Disease. While we not saying that a left-brained bias is causal of PD, it would appear the two are linked. Life long left-brain overactivation might make one more prone to PD and other chronic conditions, and, moreover, then feeds the symptoms and hastens the rate of progression of the disease. Conversely, having PD is likely to increase left-brain activation, and the disconnections which come with the resulting further inhibition of the right-brain.
If this is the case, there will be significant benefit in seeking therapeutic strategies which ameliorate this hemispheric bias, various forms of which I have suggested in the above discussion. Indeed, these are all precisely the type of strategies I’ve been implementing for some time and have contributed to my own progressive symptom reduction.
We might ask whether left-brain overactivation arises from nature or nurture in the first place. For myself, the answer is provided by Bonnie Badenoch in her book
The Heart of Trauma: Healing the Embodied Brain in the Context of Relationships,
in which Bonnie makes a convincing case that a major causal effect is development and shock trauma. This concurs with my own perspective that background traumas are one of the major contributing factors to idiopathic Parkinson’s Disease,
DEVELOPMENTAL AND SHOCK TRAUMA AND PARKINSON'S DISEASE.
THE LINK BETWEEN LEFT-RIGHT BRAIN IMBALANCES AND DORSAL VAGUS ACTIVATION
Readers might be saying to themselves now "but hang on, for some time, Gary has been explaining to us that it may be the overactivation of the Dorsal Vagus Nerve which is causal in many cases of idiopathic Parkinson's Disease... so how come the change of mind/focus to the left-brain overactivation?"
Well, the answer is, of course that body and mind are indelibly linked, as are Dorsal Vagus and left-brain overactivations. These links are beautifully explained in the above mentioned book by Bonnie Badenoch, which brings together the latest science, clinical outcomes and personal experiences to explain how trauma and symptoms are interwoven with our relationships. In this book, Bonnie also unites the work of Dr Stephen Porges on the Polyvagal nature of our Nervous System with the lessons from Iain McGilchrist on the Divided Brain. Indeed, Bonnie provides a very elegant explanation of how the two perspectives compliment each other. Here are a couple of very important excerpts from the book on this, which I feel are vital for this understanding.
"Culturally, we find ourselves at a crisis point in terms of ongoing low-level sympathetic activation. There is a reciprocal relationship between fear and the tendency to shift into left-hemisphere dominance. In general, the conditions of our culture are not conducive to ventral settling, and once we have made the adaptive shift into left-hemisphere dominance, our disconnection from others combined with cultural conditions supports remaining in that state."
"In this left-dominant state, our attention is drawn to completing tasks and controlling behaviors rather than participating in the relational moment. We lose the orientation toward one another that calms our system along with the sense of meaning that arises from being connected to something larger than the needs and wants of our individual self."
"In short-term conditions of threat, these changes are essential for survival; as a long-term strategy for safety in a threatening world, our system deems them necessary even with the considerable cost they bring. At certain moments, danger may escalate to the point where we have a neuroception of helplessness. Then, the third ANS branch, the unmyelinated dorsal vagal parasympathetic awakens to slow our systems in preparation for the possibility of death and also activate an ancient strategy to conserve metabolic resources in case we don’t die. We could say that we feign death to avoid death...”
".., when our threatened system senses that fight and flight are impossible, additional pathways are activated and wisdom guides our movement toward collapse and dissociation as our heart and breath rates slow, signs of aliveness and engagement leave our face and eyes, endorphins are released to diminish the pain of death, and the sacral parasympathetic pathways may release our urinary tract and bowels. At the same time, our system is conserving metabolic resources for a safer time when we can come back into our bodies again."
"When we experience humiliation, we are right at the gateway of dorsal vagal activation...."