In 1996, a 50-year-old man in Nova Scotia noticed his eyelids had started closing on their own and he could not keep them open. He eventually was diagnosed with dystonia of the eyes and was functionally blind, even though his eyes themselves were fine. He discovered something odd. His eyes did open on their own in a few specific situations – when he played his fiddle, when he turned on his chain saw, when he walked into a doctor’s office, and the time he walked his daughter down the aisle at her wedding. As soon as those activities ended, his eyes clamped back shut.
(In 1998 he underwent surgery for the eyelids and had muscles severed so he can now open his eyes again.)
It is a mystery to researchers why certain situations or activities alleviate dystonia symptoms. There are many such mysteries.
A Japanese pianist found that the thumb of one hand started curling in so badly she could not play piano easily, shake hands, shampoo her hair or press enter on a computer. However, her thumb was fine as long as she swung her arms casually at her side.
An Italian journalist developed dystonia of the neck so severe he was unable to control his head spasms or drive a car. He discovered in 2015 as he walked down a street wearing headphones, that if he moved to the music his walking improved. Over time he experimented, finding that when he danced his body suddenly showed no dystonia and he made a Youtube video of how fluidly this happens.
A New Jersey marathon runner found she was no longer able to run, and was diagnosed with runner’s dystonia. She discovered however that she still could run upstairs or backwards. With determination she practised and in 2015 not only ran a half marathon backwards but set a world record for fastest time running backwards at 2 hours and 46 minutes.
Some people with vocal cord dystonia who can barely speak above a whisper discover their voice returns to normal if they speak in falsetto or sing. Some with vocal cord dystonia have been told by their partner that they talk in normal voice in their sleep.
Such oddities have confused patients and researchers and made people wonder about the legitimacy of dystonia as a medical condition. However people with dystonia had the clear experience that this was not faked and clinical research has now confirmed it.
Most people with dystonia struggle to get through the day. For many it is a process of every few moments adjusting body position away from pain, trying to not spasm. This experimentation has sometimes landed on finding a gesture that works, a position that momentarily seems to relieve or even remove the dystonia, however briefly.
Recent studies suggest that the brain looks at motions very task specifically. Researchers and patients have wondered if solving this mystery might be a key to understanding dystonia, or even to understanding the brain and movement for everyone.
In history there are pictures of people with neck dystonia who are able to correct their neck tilt if they gently touch their chin, cheek, forehead or back of head. The position of the touch varies for individual patients but the pressure is not technically enough to cause the huge reaction. The part of the body touched is often far from the dystonic muscle affected. A person with a very tight neck muscle on the left side, for instance may get immediate relief by gently touching the right temple.
In 1894 French neurologist Edouard Brissaud took pictures of seven patients with the twisted neck condition. In some where the patient is touching the second finger of the hand to the chin, there clearly is less tilt of the neck. Broussard found that some patients could alleviate neck spasm by placing the head against the wall, resting the head against a pillow, or by touching the nose or forehead.
1n 1900 painter Amedeo Modigliani portrayed some figures in postures that look like dystonia. In several, his partner Jeanne Hebuterne has her head angulated. Often her hand is touching two fingers to her face in a common alleviating gesture for neck dystonia.
We now know there may be several types of such movements.
A. FORCING THE MUSCLE
If a person whose eyelids clamp shut reaches up and physically lifts the eyelid to open it, this can open the lid. However the opening is done by force and seems to last only as long as they apply the force. The movement is always in the opposite direction to the dystonia, so is called antagonist. If a person with one hand pushes their neck into normal position this can correct the dystonic tilt. The force often causes pain but the neck is straighter. Patients and researchers have observed that the body strongly resists this force, and the moment the pressure is released the dystonia bounces right back. This type of motion is called a forcible trick or motor trick though the term ‘trick ‘ may be misleading.
B. REDUCING THE CHALLENGE
-Reducing the need to also fight gravity- Our bodies constantly have to deal with the push of gravity, so when we are sitting or standing, our anti-gravity muscles are activated. With dystonia there may be a double challenge – the dystonic force and the need to resist gravity. Patients with neck dystonia often find that resting the head against something can reduce the discomfort or that lying in bed they immediately feel some relief. Those who rest an arm or hand on a cushion, their back or head on the wall, may be using this type of accommodation. These movements may not be so much tricks however as chances to ease the load.
-Assisting the motion by other muscles helping. Some people with dystonia find when they want a muscle to stretch and it resists, their body can call in other muscles to help. To lift the head may be easier if they scrunch their shoulders, or bend at the waist, as if the strength of the shoulders helps the neck. Some find that when they try to lift their head it is easier if they open their mouth wide or scrunch their eyes. The explanation of why that works is not clear but some patients say it feels like those other muscles are trying to assist.
C. THE CLASSIC SENSORY TRICK/ GESTE ANTAGONISTE-
Many people find their dystonia is immediately reduced by gently touching some other part of the body – the chin, forehead, back of head, cheek – even though that is not the area with the dystonia. People usually discover it by accident as they move around to try to find a more comfortable position. The phenomenon operates nearly as if the two distant parts of the body were attached on a string, and usually the very second the person stops touching the skin, the distant muscle tightens back up. The effect therefore is only for a few seconds, rarely more than a minute – so very transient.
This effect surprises patients who discover that their troubled body for those seconds remembers how to be normal. Some people get the effect with trunk dystonia when they touch the hip or the knees.
What precisely matters for the trick to work? People have experimented. Some whose neck pain is gone when they touch their forehead may get the same effect if they use a rubber glove to touch the forehead, so do not seem to need the skin to skin contact. Others however find they need the skin to skin touch. Some find that if another person touches the forehead for them, the trick still works while others find it only works if their own hand touches the spot.
D. PRE-TOUCH EFFECT
One patient with runner’s dystonia that happened when he ran a track counter-clockwise found that the dystonia was less if he ran it clockwise and that it was also less if he just imagined running it clockwise.
This effect may present other insights about brain wiring. People who find that a touch of the chin loosens the neck have occasionally noticed something else. The neck starts to loosen as soon as they raise their hand towards touching the chin, before they have even touched it. Some find that if they just imagine touching the chin, the neck muscle will loosen.
This particular effect at first seemed to suggest that the trick was only psychological. However brain scans have confirmed the mechanism is real. The fact that it happens without an actual touch sensation has made researchers reassess calling these all ‘sensory’ tricks. This category of trick seems related to proprioception, the body’s awareness of its position without having to look, such as knowing if you are standing on soft grass or hard cement, or being able to throw a ball without looking at your arm.
Brain studies have shown that in any body motion, there are stages of preparing for it, in a ready-set -go pattern like a runner at a starting gate. With dystonia there may be a delay at the middle stage or ‘gating’, creating some of the slower and jerkier responses. One theory is that the body, in preparing to get the effect of a touch sensory trick, is anticipating effects it will feel from it. The mechanism involved may be similar to how if you see the finish line of the race, or you see ahead of you a loved one you have not seen in ages and rush towards them, your body starts to feel the relief that you will feel when you are there with them. It is an anticipation. The body before the moment prepares for the moment. Some people call this type of trick ‘imaginary ‘ though such a label could be misleading.
D. SPECIFIC EXCEPTIONS
There is a particularly odd category where another entirely unrelated type of motion suddenly seems to make the dystonia disappear. Some find that while burping, yawning, whistling or coughing the dystonia seems nearly gone. Understanding what is going on in these situations may reveal secrets about the intensely task specific nature of the brain’s instructions to the muscles or the brain’s treatment of feedback.
People with hand dystonia who can barely hold a pencil sometimes find they can still write well if they use chalk, or they can still easily use scissors or do jigsaw puzzles. Some who can no longer make fine details of writing can still make the fluid motions of shorthand, swirls or still write upside down. Some with jaw dystonia so the mouth clamps shut, find that there is much less pressure to close if they hold a toothpick or toothbrush in the mouth. Some with problems swallowing find that the hardest thing to swallow is water but that chewing a cashew nut is quite easy.
Some with neck dystonia find that the condition is nearly gone if they dance. garden, paint or count backwards. Some with musician’s dystonia find that if they change the embouchure of their instrument they are fine. Some violinists with dystonia affecting a few fingers find that if they change the fingering for the musical number where the dystonia is bad, they are fine. Golfers who find the short strokes and the fast, downhill and left-handed putts hard to do, may find that the long strokes are still easy. Some who struggle to walk can actually run with fluid easy stride. People with dystonia often explore their condition, not necessarily because they want to but because they are uncomfortable and trying to shift pain but the effect is in essence field research. The body in such situations may be revealing something important about the brain and messages to and from muscles.
F. TRICKS THAT DO NOT HELP
There is a small category of times when the action the person takes makes the dystonia worse. These are called ‘reverse sensory tricks’. In one patient with neck dystonia, the condition was worse if they touched the back of the head, and worse if they closed their eyes. Some studies find that vibrations near the dystonic muscle make it worse, though a large number of patients find that such vibrations make it better. One of the many mysteries about dystonia is that a trick that works amazingly well for some people has no effect for others and for a very few even gives momentary new discomfort.
The existence of sensory tricks/ alleviating maneuvers is now well recognized by neurologists. Since 2014 having a sensory trick has been accepted as part of the official diagnostic criteria of organic dystonia. Parkinson tremor, Hemichorea-hemiballism and even essential tremor can be somewhat differentiated from dystonia when a study is made of sensory tricks.
Here are what some researchers have said about the sensory trick/ geste/ maneuver.
- There appears to be a specific body area unique to each individual that works for the sensory trick experience. This topographic area does not always include the nerve territory distribution of the area with dystonia.
- Finding a gesture that works seems to be self-developed and therefore somewhat intentional but it has aspects of being subconsciously acquired.
- Better appreciation of the sensory trick and the mechanisms of the sensorimotor interactions underlying it may provide clues and open new avenues for treatment.
- The sensory trick remains a fascinating and poorly understood phenomenon
- The exact mechanism remains elusive
- The remarkable efficacy of the geste antagoniste and the considerable variety in performance, duration and EMG pattern of these manoeuvres warrant further investigation.
- Sensory tricks are nearly universal and may have therapeutic implications. Better understanding of the mechanisms involved may lead to new tools to treat the condition.
- Sensory tricks can be risk-free, low-cost aids with potential therapeutic and diagnostic implications
- It appears worthwhile for patients to search for possible sensory tricks
RESULTS FROM CLINICAL RESEARCH
- in one study 70-80% of those asked had found a sensory trick
- in one study of 454 people, 89.6% used a sensory trick.
- in one study 58% of patients with cervical dystonia had found a classic sensory trick
- in one study 84% of those with cervical dystonia and 71% of those with eye dystonia had found a sensory trick.
- in one study of 19 patients with lower cranial dystonia, ten had found sensory tricks on their own and 8 more were discovered during the clinical evaluation. Patients are not always aware of a possible sensory trick.
- 54% of those who had found one gesture that helped had also found 2 or more.
- 90% of those with dystonia in one study were able to demonstrate it in the clinic
- in one study of 47 patients with cervical dystonia, 12.8% had a negative effect on their dystonia when they used some motions.
b. Use/ efficacy/ did it help?
- 82% of those with neck dystonia had less head deviation when using the trick
- 60% of those with neck dystonia had improved head posture using the trick
- 27% of those with neck dystonia has complete cessation of tremor using the trick
- in one study of 32 patients with focal or segmental dystonia. 90.5% reported that the sensory trick worked and later clinical examination confirmed it.
- in one study of 454 people, 43.4% said the trick gave them partiaL improvement, and 39.8% reported marked improvement of dystonic posture..
- in one study of 50 patients with cervical dystonia, 42% of those with a trick found it lasted a few seconds to one minute while 58% said the trick lasted more than one minute.
- in one study only 2 of 33 patients found that the trick lasted longer – from a few minutes to a few hours
- in one study 9.5% of patients found some of their tricks no longer worked. In another study 45 of 50 found their trick still worked over time.
- younger people have often found more sensory tricks. Age of onset does not seem significant in other studies.
c. What aspects of it worked?
- of 81 patients with cervical dystonia, if another person touched the spot only 27% felt the trick still worked
- only 33% of patients found the trick worked when they used a foreign object not their finger to touch the spot
- 21% found that the trick worked even if they just imagined it
- 82% found the trick did not work if they were also doing something cognitively demanding like counting
d. What are the clinical results of using such tricks?
- there are definite neurophyisological changes when a patient uses some of the tricks
- in EMG polygraphy, for 66% of patients there was a decrease in recruitment density and amplitude in the dystonic muscle when using the trick
- in EMG polygraphy there was an increased tonic muscle activation for 34% of patients when using the trick.
- electromyograms found an improvement in dystonic muscles when doing a trick where the patient played an electric piano. The improvement was less when the sound was turned off, suggesting that just touching the keys was not the only element of the trick.
- electromyography found that a five minute ice massage improved the affected muscles for patients with embouchure dystonia though the effect only lasted one minute.
- neuroimaging examined functional sensorimotor maps in the brain. Sensory tricks were found to correct abnormal activation patterns in some areas.
- EMG and positron emission tomography in patients with cervical dystonia found the trick reduced activation of the supplementary motor and primary sensorimotor cortex contralateral to the side of dystonic posture
- one study found that when the trick is done, there is hyperactivity of the parietal cortex. This area of the brain is normally involved in multimodal sensory integration.
- electromyography found a decrease in activity of dystonic muscles in 52% of cervical dystonia patients using a trick
- electromyography found a complete cessation of dystonic activity in the sternocleidomastoid, splenius and trapezius muscles during some sensory tricks
- in 72% of patients with cervical dystonia a trick that worked when they did it, did not make any electromyogram change when the trick was done by an examiner’s hand
- fiberoptic laryngoscopy confirmed that some tricks change dystonia laryngeal muscle activity.
- the trick seems to normalize TMS parameters such as intracortical facilitation and may normalize or improve blink reflexes
- in one study where the examiner noted decreased activity on surface electromyography in the patient’s brain during a trick, the patient did not himself feel the trick had worked.
e. What are other uses of the trick?
- there may be a link between if the patient is able to find a sensory trick and whether injections of botulinum toxin will work. Those with effective sensory tricks are often the ones who respond well to the injections.
f. Current theories about what is going on with the tricks
- Dystonia involves decreased inhibition in the nervous system. It raises to abnormal levels the facilitation- to-inhibition ratio in the brain. The sensory trick helps decrease that ratio to make it more normal. The tricks decrease the abnormal cortical facilitation of dystonia.
- Patients with dystonia have a loss of surround inhibition and less selective control of movement. The sensory trick reduces the facilitation-to-inhibition ratio of the field surrounding the moving muscle and if the dystonic muscle is in this surround, the dystonia may be suppressed. eg. for speaking, the eyelids are involved in the surround cerebral territory so with eye dystonia, speaking may help.
- There is increase in activation of the parietal and bilateral occipital lobes using the trick.
- There is decreased activation in the supplementary motor area and the primary sensorimotor cortex with the trick.
- There is an increase in tonic muscle activation with the trick. This activity may counteract dystonic movements and produce harmonization of movement.
- Dystonia is reduced with the trick because there is modification of the sensory motor integration at the cortical level. The sensory trick in neck dystonia modifies the information the parietal cortex gets about head position.
- Sensory tricks normalize the pathologic reflex circuits that in dystonia have led to ‘abnormal gating’
- Since dystonia is a mismatch between sensory input and motor ouput, the way the sensory trick works is that it adjusts this mismatch
- The sensory trick may be decreasing muscle spindle activity, dampening spindle afferent traffic.
- The sensory trick reduces recruitment density and amplitude