In his defining lectures in 1868 on sclérose en plaque disseminée, now known as multiple sclerosis, Jean-Martin Charcot indicated that tremor was one of the common symptoms of this disorder. He added that no one should be caught in the snare of confusing it with the tremor of Parkinson’s disease. In fact, the Frenchman’s presentation was to show the differences between these types of tremor. In his description of the symptoms in MS he began with tremor.
In his presentation of the case of Mademoselle V, a young woman aged 31, he noted she had a tremor that was absent at rest, unlike Parkinson’s tremor, but became more marked as she raised a glass towards her mouth, causing her to spill the water.
The tremor, Charcot said, was an intentional tremor that worsens when an action is attempted but absent when the limb is at rest. It was not only seen in MS, as he had seen it with other conditions as well. Although he concentrated on a description of tremor in the arms and hands, he indicated that tremor could also be seen in the trunk, head and legs, and even in the muscles used in speech, resulting in a characteristic “scanning speech”.
Charcot explained that the tremor of MS was usually a late symptom, if it appeared at all, although he had seen it in earlier cases on rare occasions. He also noted that people with tremor in MS often also had a staggering gait, known as ataxia. His student, Georges Gilles de la Tourette (remembered today for his description of Tourette Syndrome) used to map the gait of ataxic patients by having them walk on long strips of paper with the soles of their feet inked.
Charcot felt that MS was resistant to most available forms of therapy but perhaps would be treatable when more was understood about the underlying mechanisms of the disease. At the Salpêtrière, the huge French hospital in Paris where Charcot worked, therapy was still attempted for cases of MS and the approach for ataxia was a suspension apparatus that held the person elevated by straps around the chest and under the arms (see page 6).
Later, investigators clarified that the commonest tremor and ataxia in MS were due to lesions affecting the cerebellum and related structures, an area of the brain that is particularly involved in coordinating muscle movements. The intention tremor mentioned by Charcot is usually due to involvement in the fibres leaving the cerebellum.
An English neurologist of the early 20th century, Sir Gordon Holmes, noted that the intention tremor of cerebellar involvement had errors of rate, range, direction and force of movement, and neurologists developed specific tests to observe the tremor, the best known being the finger-tonose test (see page 11), and the heel-shin test.
Although cerebellar tremor is the most common tremor in people with MS, there are other forms of tremor that could be seen. Everyone has a physiological tremor, which is barely visible in most people in their outstretched hand, and more evident if they become anxious (or if they put a page of paper on their hand to make it more visible). In some this is more obvious and is called an essential tremor, often familial, and can affect the hands, head or voice (as it did in the actress Katherine Hepburn). If there is a lot of sensory loss, a person with MS could have more unsteadiness in their hands if they are not watching them closely, and have ataxia due to the fact that they are not fully aware of where their numb feet are being placed (sensory ataxia). To compensate for sensory tremor and sensory ataxia a person may watch his or her hands when they are carrying out tasks or look down when walking. He or she may touch furniture or the wall to get a better sense of their position in space.
The assessment used to document the status of a person with MS is the Extended Disability Status Scale (EDSS), developed by Dr John Kurtzke, which includes a section to rate the cerebellar involvement in the scale. The scores are from zero with no involvement, through to six for severe and incapacitating tremor and ataxia. If the person also has weakness, spasticity, or sensory loss they can have even worse balance and gait and these are reflected in other sections of the scale.
During the 20th century, neurologists following the description by Charcot recognised that tremor and ataxia were very difficult to treat and were very disabling to the patient. The basis of the tremor and ataxia was an incoordination of muscle movements and resulted in the unsteady action of the limbs and other muscles.
Over the years, many physiotherapy and rehabilitation techniques have been tried without much success, although training in mild cases can be of assistance.
Further, in the last 50 years attempts to provide benefit with drugs such as tranquillisers, anticonvulsants, a diuretic called acetazolamide, high doses of an antituberculosis drug isoniazid and various anti-Parkinson drugs were tried but these did not provide much help. Using a beta-blocking agent such as those used for high blood pressure (propranolol) can reduce tremor when it is mild, but is most helpful in physiological and essential tremor (which explains its use by some public speakers and musicians who have tremor when they are on stage. It has been prohibited in Olympic sports such as shooting, because athletes were using it to steady their physiological tremor).
Physical methods such as training and education to compensate for the incoordination can be helpful. Steadying a limb by bracing a joint can help, such as resting an elbow when using the hand. Adding a third or fourth point when walking by using a cane or walker, can help with an unsteady gait. Adding weights to the wrists can provide assistance in some cases. A head rest helps if there is head tremor. In rare cases neurosurgery has been used for marked tremor.
This has been more successful in Parkinson’s disease and other movement disorders, especially if one side is more affected, but not usually indicated in MS as it creates one more lesion and can have many potentially serious complications.
In this issue, current understanding and therapy of ataxia and tremor will be reviewed. Dr Marcus Koch will outline the pathophysiology that underlies tremor and ataxia, and Dr Sundus Alusi will explain how it is evaluated and measured. Dr Roger Mills will discuss the pharmacological approaches to managing ataxia and tremor, and the surgical approaches that can sometimes be helpful. Dr Guy Nagels will explain attempts at rehabilitation approaches to manage and compensate for these symptoms.
Although ataxia and tremor do not affect everyone with MS, when it does occur it can be one of the most frustrating and difficult problems. It is hoped that some practical and useful information in this issue will bring assistance to those who are dealing with these symptoms.
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