Focal Dystonia of the Hand, and what the Brain has to do with it

Biology 202
2001 Second Web Report
On Serendip

Focal Dystonia of the Hand, and what the Brain has to do with it

Henrike Blumenfeld

The body is complicated, and often the origins of a condition are all but obvious. Focal dystonia of the hand is one disorder whose underlying cause has been found in the more recent past. Although it can be genetic (1), the form of focal dystonia of the hand I look at here is caused by environmental factors (2).

Focal dystonia of the hand is a condition characterized by a loss in motor control of one or more fingers. A single muscle or group of muscles is involved: muscles in the hand and forearm tense and tighten, with the result of making the hand (or part of it) curl (2). Musicians who have intensively practiced their instruments over a number of years are a group most affected by this condition. The reason is that focal dystonia can be caused by the repetitive movement of the fingers over a significant period of time. The condition was long known as "occupational hand cramp." (3). It can easily be misdiagnosed as simple overuse or stress of the hand (1). Although it may not be obvious at first sight of the symptoms, the level at which the problem is caused is not the hand, but the brain.

Researchers at the University of Konstanz report "overlap or smearing of the homuncular organization of the representation of the digits in the primary somatosensory cortex" (3). Given that functions such as motor control cross over from the right side of the body to be represented in the left hemisphere, they found that the distance between the representations of individual fingers was smaller in the somatosensory cortex side corresponding to the hand that had undergone continued repetitious training (the left hand in case of violin players for example).

What does all this mean in terms of the brain? Looking at the central nervous system as an input-output system, in very simple terms we can observe that a specific input is presented over and over again - in this case the stimulation of the fingers that play the violin - and as a result the organization within the box changes. More specifically, there is a one-to-one correspondence between input and internal representations of this input: all fingers are individually represented on the somatosensory cortex. But somehow, as these regions of representation begin to smear or overlap, the one-to-one correspondence is blurred.

And the result? The problem turns into one of perception and motor control. Subjects with dystonia of the hand consistently are unable to localize light pressure stimuli applied to the tips of the fingers on the correct finger(4). Further, fingers in question cannot be moved individually, and specific movements or movement sequences cannot be controlled any longer (5). We get similar effects in blind people who read Braille with several fingers at once: they develop a single representation of all these fingers on the somatosensory cortex, but are not able to determine which part of the information received in the brain comes from which finger (6). Psychologist Thomas Elbert further points out a parallel of this in all of us: our toes are generally stimulated only simultaneously as we walk, and most of us have trouble telling which of the middle toes has been touched upon application of a light pressure stimulus. Indeed, our toes are not individually represented on the somatosensory cortex as our fingers are (6).

As we can see, through some process, representations in the brain have become reorganized in a way that makes it difficult to distinguish between certain afferent inputs. These inputs enter the peripheral nervous system close to each other, say via two adjacent fingers, and have been presented to the system simultaneously over and over again. The examples are stimulation of the first and the second fingers in quick musical sequences - so quick that stimulation can be seen by the system to happen simultaneously - or continuous use of several fingers in reading Braille (6).

This continuous pairing of two (or more) stimuli, until their representations in the brain merge, is not a new idea. It has been established that if two connected neurons are stimulated at the same time, the connection between them is strengthened (7), and rules of associative learning have been based on this idea. Fittingly, Dr Merzenich of the University of California San Francisco calls focal dystonia of the hand a "learning-based catastrophe" and a "failure of the brain's learning processes" (5). Consequently, he focuses on developing techniques that will help to "re-normalize the learning system", in helping to newly distinguish the areas on the somatosensory cortex that have become blurred. Although this approach is very new, Merzenich claims some good results in training children with linguistic impairments, such as dyslexia, which show similar blurring of representations in the brain (5).

The form of focal dystonia of the hand that is caused by repetitious training of two or more inputs is a clear indicator of the brain's ability to restructure itself. Traditionally, the belief has been that the capacity to restructure is present during childhood, and that the adult brain shows little room for change (6). However, as we can see, the adult brain is still capable of rather far-reaching change, and the old view of a hard-wired adult brain is thus being challenged. Further, we have seen that the central nervous system reacts to the kind of input it receives from the outside world, and the context this input is presented in (what are other impulses presented at the same time?). According to what these inputs are, there seems to be at least some leeway for the brain to adjust, in order to process these inputs in a way that may be more efficient. Indeed, this movement towards efficiency is fulfilled in the combining of various fingers into one larger representation in blind readers of Braille. Those skilled at reading Braille with multiple fingers are quicker than readers of Braille that use only a single finger. However, focal dystonia of the hand also suggests that there may be some rare inputs (such as long-term repetitious practicing of fast musical sequences) that "trick" the central nervous system into making changes that are clearly less beneficial.

 

WWW Sources

1)The most dangerous medical condition of all: Focal Dystonia, Largely anecdotal site about musicians' experience with Focal Dystonia

2)Research: Recent Findings Lead to New Understanding of Dystonia , More technical but very informative article about Dystonia from theScientist, subscribe for free to access

3)Focal hand Dystonia in musicians, Short and accessible summary of ongoing research activities at the University of Konstanz. Further links on the dystonias available from this site

4)Cortical Representational Plasticity, Brief research summary on brain plasticity, repetitive stimuli and focal dystonia

5)"Catastrophic Breakdowns" in the Brain's Learning Systems, Article on Dr Merzenich(UCSF)'s research into focal dystonia, other neurological disorders, and his theory about seeing them as breakdowns in the brain's learning system

6)Radio National Health Report on Brain Plasticity, Transcript of an interview with Thomas Elbert of the University of Konstanz about focal dystonia in musicians and Braille reading.

7)Enchanted Mind: Brain Plasticity, General site about brain plasticity, the learning process, and how to maximize this process.

 

 

Continuing conversation (to contribute your own observations/thoughts, post a comment below) 01/03/2006, from a Reader on the Web I was diagnosed with Focal Dystonia in my writing hand in early 1999. I was treated with Botox but they gave me too much of an injection and my arm/hand was paralyized temporarily for approx. 2.5 weeks. My writing became much better for about 1.5 weeks after the injection but the pain before the progress was not worth it for me to go back for more (approx. 300.00 cdn per dose). I suffer more so today and can barely hold a pen anymore and if I do it is only for a few minutes and my arm and hand ache for a few hours following. My question is: Does stress or anxiety or depression exacerbate the dystonia i.e. nervous and excessive shaking of the hand? Is there anything else I can do to help myself?

 

 

This condition can be overcome. I have just been watching a TV1 New Zealand programme on the life to date of pianist Michael Houston. During this it was revealed how he was severely affected by Focal Dystonia for about five years. In particular this condition was aggravated through learning, performing and recording the 32 Beethoven piano sonatas in the space of about 3 weeks.

 

Through the interventions of a sports physiotherapist, an acupuncturist, a doctor dealing with the development of the muscles of the body, and pianist Rae de Lisle, he has overcome this to the extent that he has been able to make a full return to being a concert pianist. He had been advised to quit piano playing because of the condition, but neither he nor his supporters agreed with this suggestion, and the results of their endeavours is a happy one ... Brian Swale, 10 June 2006

 

 

Well, maybe my diagnosis of this dystonia thing has come to rest. I am not a musician, just an average 50 year old woman who is right handed and if you can call anything fortunate about my condition is that it has affected my left hand. Left index finger acts the weirdest, but my left hand just acts funky. My journey to this diagnosis hasn't been as weary as some I have juat read about. It's taken about 3 doctor visits - fisrt to a hand surgeon who then sent me to a neurologist who then ordered an MRI, and MRA and then fun of all fun, an EMG. Which at one point, I was tempted to get up off that table and stick the needles in my boyfriend who had dutifully been holding my feet down during my jerks from the electrical shocks. Yes he really loves me. My question now - what now? My dr. prescribed the drug they use in treatment of Parkinson's disease. This whole experience is starting to get on my last nerve. Any advice, words of wisdom, comfort......is welcome ... Mary Wade, 1 August 2006

 

 

I would like to correspond with any others who have been diagnosed with focalized dystonia of the hand. I have been the whole gambut of meds, botox, and so forth. Nothing has helped ... Diane, 8 October 2006

 

 

Hi... not really sure if i should say anything at all here... but i was reading where u had been diagnose with focal hand dystonia in 1999. I have it to and i belive that it started in the fall of 2002 and really devloped in 2003 and it started out that i could not printed the digit 7 i can make the horizontal but not the vertical part of the seven.. i have been to the institute of health in bethesda maryland.... my question to you is this ... how and why does it start where does it come from.. and what can we do to get rid of it.... thank you ... Craig, 10 October 2006

 

 

I am a physical therapist who has worked with all types of soft tissue injuries and nerve entrapments throughout my entire 47 year career. In 1972 I discovered that by the systematic 10 minute wrapping of involved muscular groups, I could slow the chemistry of the muscles and thereby temporarily decrease their irritability. After a number of wrappings the tissue returns to normal. Muscle is contractile by nature. Its job is to move the bones, and it can only contract. Muscle lengthens only when the opposing muscle group contracts. After overuse or injury, muscles sometimes become confused and begin to contract on a reflex basis in cooperation with the spinal cord. The surrounding tissue becomes filled with fluid and can be hot or warm to the touch. A forearm often feels like a sausage instead of being soft and pliable. Healing can cause hard restricted bundles of muscle fibers to form within the soft tissue. These areas must be released and the tissue pliability restored to regain smooth coordinated muscle function.

 

When confronted with reflex activity the patient endeavors to perform his normal activities. Because his muscles don't respond easily, larger stronger muscles are often recruited on a voluntary basis. The brain is then involved. These larger muscles overpower the smaller muscles and result in the development of faulty movement patterns. Contracted and distorted muscular patterns often result along with nerve entrapments and strange patterns of functional movement.

 

These complex neuromuscular problems can be resolved by wrapping the involved sections of the body with moist medium weight terry cloth towels filled with natural ice, and then gently massaging and stretching the involved musculature. Treatment is given with the musculature resting in a plane neutral to gravity. The inherent contractility of the muscles must be respected. Rough treatment of the unhappy muscular tissue can make the condition worse. Reicing of the areas further decreases the irritability of the tissues. During the application of cold, the core temperature of the patient's body is kept warm by the application of large abdominal hotpacks or by placing the patient on full body heat.

 

Two weeks after the soft tissue returns to normal, reeducation of the faulty voluntary movements can begin. Frequently the most basic of fine movements must be taught first. Use no resistance. It is a bit like reeducating poilo patients after they have forgotten how to move. Relaxed movement must be taught through all ranges of motion. Sometimes the patient has never learned to do relaxed movement, and it is a foreign concept to him. Patience is required on both the part of the teacher and the student.

 

I love working with these complex cases and get excellent results. I use every type of technique which I have learned in my career as a physical therapist, synchronized swimming coach, ice dancer and performer. The cases are fun and mentally stimulating. I encourage you to start using cold to decrease the irritability of the muscles. Ice works quickly and effectively and is a very effective therapeutic tool ... Elizabeth Morris, 10 January 2007

 

 

Focal Dystonia of the hand question related to stress. When I am rushed or stressed, my writing hand (the affected hand) is practically useless. For unexplained reasons my hand will periodically print pretty well but writing is out of the question. The cramping is terrible and yes, I do think stress exacerbates this painful condition ... Barbara Perrin, 21 January 2007

 

 

Good contribution. Focal dystonias are typically enhanced by Anxiety/stress, and treatment may be helpful (especially when dystonia and essential tremor are paired). Retraining is worth a serious try,but exercise intolerance is a limiting factor. Botox injections can work (if dose is correct) for up to several months, but may cause rebound worsening. Med alternatives include beta blockers (e.g., propranolol) to reduce tremors and performance anxiety), certain anti-seizure meds, and antiparkinson agents may be tried. The link between dystonia and mitochondria oxidative posphorylation may suggest a role for Coenzyme Q10. Feedback would be of great interest ... SM, 4 February 2007

 

 

After having consulted with various specialists regarding the emergence of focal dystonia in my Right Hand litte and ring fingers, and after persuing your information, I was wondering if you have any suggestions regarding the alleviation/'cure' for this problem?

 

My problem developed spontaneously in approx February/March 2006, as a result of a 12-year period of being a typist, and consists of the said fingers 'curling' or 'bunching' up after no more than perhaps 5 words (after being capable of 130 words-per-minute). There is little pain, and perhaps an occasional aching sensation.

 

It can also occur with prolonged use of chopsticks, but to a much lesser degree.

 

It has been suggested to me that a magnetic wrist band may be of some benefit, and after consulting with a neurologist, it appears the neurological pathways are of normal conduction.

 

Any advice you may be able to offer would be greatly appreciated ... Kris Penny, 28 February 2007

 

 

I have been diagnosed with focal hand dystonia since 1999, I had just finished RN school and had been writing more in the last 5 years than in my entire life. I went to a neurologist and have been on beta-blockers and trialed many other medications for parkinsons and even requip without success, I have had 4 botox injections over the years and all did not improve my writing and the last left my index finger numb and still having trouble, the combination of inderal and clonazapam seem to help me write better, but I am looking for more information on treatment to help me write, I posture and hold my hand strangly to write, I perform many tasks as an RN and without shakiness but simple writing makes me shake and is begining to affect my performance. Do you have any suggestions, I also tryed hand therapy but the therapist was not even familiar with my problem and not helpful at all. Also can you suggest anyone in the seattle area that is familiar with this problem because my neurologist is not sure what else he can do for me. Any information would be helpful. I appreciate your time ... Mary Hutchins, 25 April 2007

 

 

I have been diagnosed with focal dystonia in my right hand this month. It appears it is made worse by stress, but not really fixed by calmness. My solution is to write with my left hand - the condition does not usually spread from one hand to the other!

 

Perhaps you could try that. It's hard, but much easier than writing with the affected hand.

 

There is also a relevant website: dystonia dt org dt UK ... Richard Donkin, 30 April 2007