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MS information for health and social care professionals Tremor

Tremor is characterised by involuntary uncontrolled movements. Tremor may be present when a person is voluntarily maintaining a posture against gravity (postural tremor), during voluntary movement (kinetic tremor) and during target directed movement (intention tremor). Intention tremor is usually the most marked. The tremor amplitude increases during visually guided movements towards a target and occurs at the termination of the movement[1]. This can be observed during the finger to nose test when the person is asked to lift their arm out to the side and then to bend their elbow and touch their nose with their index finger[2]. As the finger approaches the nose the tremor amplitude increases. It is uncommon in MS to experience tremor when the body is fully supported (rest tremor) although head and neck tremor can still be present when lying down. Stress and anxiety can exacerbate tremor.

The exact mechanism of tremor is unknown but is thought to be due to lesions in the cerebellum. The cerebellum is responsible for coordinating movement and smooth muscle activity. Cerebellar system involvement is common in MS. In addition to tremor a person may also experience cerebellar dysarthria and nystagmus. Dysarthria may present in various ways such as slurring, slow rate of speech and equal stress given to syllables within words or sentences that have inappropriate silent intervals (scanning speech).

About one third of people with MS have tremor. It is one of the most disabling symptoms of MS causing the person to become dependent as many daily activities become difficult to perform such as writing, eating, dressing and personal hygiene. Subjects with severe tremor have a high level of disability and a loss of independence in activities of daily living. A survey by questionnaire, undertaken as part of the EU funded study TREMOR (de3216), found that people with MS who had moderate to severe tremor were unable to continue in their employment and had to either give up or greatly modify their leisure activities.

Commonly a person tries to cope with tremor either by avoidance of movements, by compensation strategies or by adaptation of their external environment.

Avoidance of movements

Tremor can be socially isolating. The person with tremor will often avoid movements that make their difficulties obvious. For example many will refrain from eating or drinking in public.

Compensation strategies

By strategies such as pressing the elbow firmly to the side of the trunk, a person may find that their distal tremor is diminished and they are better able to perform movements of the hand even although they will have a shorter arm reach as a result. Those with head tremor (titubation) may attempt to stabilise the head against the shoulder in an attempt to reduce the tremor. Retracting the shoulder girdle and pressing it against the back of the chair or fixing the elbow in a locked straight position may give improved distal control.

Adaptation of the external environment

People with moderate to severe tremor make adaptations such as using aids for eating and drinking. Writing is often one of the first activities that may be stopped as handwriting becomes illegible. Developments in assistive technology can offer some help[3,4]. Voice activation, keyboard modifications and dedicated software programmes can enable independent use of a computer.

There is little effective treatment for tremor[5]. Drug therapy has limited benefits. Beta-blockers may show some functional improvement whilst clonazepam and isoniazid are of little or no benefit. Botulinum toxin has been used with some success to treat intrusive head tremor in people with MS[1].

Physiotherapy treatment can show limited improvement. The approach often used is aimed at stabilising the proximal limb and trunk and retraining movement using techniques such as repeated exercise and rhythmic stabilisations. Feedback mechanisms have been used such as EMG (electronmyography)[6].

Adaptation is a key element to coping with tremor. Fatigue, common in MS, makes tremor worse and so planning the day's activities appropriately is important. New methods for daily activities should be implemented and where necessary aids should be utilised. Stabilising the head against a headrest may reduce head tremor and make activities such as watching the television easier; holding the wrist of the active hand with the other hand may help with functions such as grooming. The use of wrist weights has been of limited benefit in dampening tremor. They can be helpful if worn during eating in cases of mild/ moderate tremor. Prolonged use should be avoided as it has been shown to increase the amplitude of tremor after the weights have been removed.

Stereotactic lesional surgery to the thalamus may be used in severe cases of tremor[7]. Deep brain stimulation or thalamic stimulation which has been used successfully in treatment of Parkinson's may also offer a new approach. The outcomes of these approaches are continuing to be evaluated[8].

References

  1. Alusi SH, Worthington J, Glickman S, et al. A study of tremor in multiple sclerosis. Brain 2001;124(4):720-730.
  2. Feys P, Davies Smith A, Jones R et al. Intention tremor rated according to different finger-to-nose test protocols: a survey. Arch Phys Med Rehabil. 2003;84: 79-82.
  3. Feys P, Romberg A, Ruutiainen J et al. Assistive technology to improve PC interaction for people with intention tremor. J Rehabil Res Dev 2001;38(2):235- 243.
  4. Ability Net - www.abilitynet.org.uk
  5. National Institute for Clinical Excellence. Multiple sclerosis - Management of multiple sclerosis in primary and secondary care. NICE Clinical Guideline 8. London: NICE;2003.
  6. Scurlock L, Jones R. Ataxia in multiple sclerosis: an attempt to develop new strategies of management. Genova, Italy; Ataxia Publisher AISM: 1996.
  7. Alusi SH, Aziz TZ, Glickman S et al. Stereotactic lesional surgery for the treatment of tremor in multiple sclerosis: a prospective case-controlled study. Brain 2001;124(8):1576-1589.
  8. Yap L, Kouyialis A, Varma RK. Stereotactic neurosurgery for disabling tremor in multiple sclerosis: thalmotomy or deep brain stimulation? Br J Neurosurg 2007;21(4):349-354.