Tremors

A tremor is an involuntary, rhythmic shaking of a part of the body. It is a symptom rather than a diagnosis, and it can arise from many different causes — some benign and requiring no treatment at all, others signalling a neurological condition that needs managing.

The most useful question is when the shaking appears. A tremor that is worst when the limb is relaxed and supported points in a different direction from one that appears only when the hand reaches for a glass.

Essential tremor is the most common movement disorder in the world. It produces a rhythmic shaking, most often in the hands, but also affecting the head, voice or legs. Unlike Parkinson’s disease, the shaking appears during activity rather than at rest — when writing, holding a cup, or bringing a spoon to the mouth.

It is frequently hereditary: many patients can name a parent or grandparent with “shaky hands”. Symptoms tend to worsen with movement, stress, fatigue and caffeine, and to improve — temporarily and unreliably — with alcohol.

The word “benign” is often attached to essential tremor, and it does the condition a disservice. It does not shorten life, but a tremor severe enough that a person cannot sign their name, eat in a restaurant, or hold a phone to their ear is not a small thing.

Cerebellar tremor results from damage or dysfunction in the cerebellum, the part of the brain governing coordination and balance. It is typically slow and appears as the hand approaches a target — reaching for a cup, the shaking grows as the hand gets closer.

Physiological tremor is present in everyone. It is normally invisible, but becomes noticeable with stress, anxiety, fatigue, lack of sleep, low blood sugar, an overactive thyroid or withdrawal from alcohol or other substances. Treating the underlying cause resolves it.

Drug-induced tremor appears as a side effect of certain medications and substances — some antidepressants, lithium, valproate, bronchodilators, high doses of caffeine. It is important to identify because it may be reversible on changing the medication, and because it is sometimes mistaken for a degenerative condition.

Orthostatic tremor is a rare disorder producing a very fast tremor that is often not visible at all. It appears only on standing, and patients typically describe unsteadiness rather than shaking, with relief on sitting or walking.

Our neurologists start with a comprehensive assessment to establish what kind of tremor is present. That means examination, a careful medication history, thyroid and metabolic screening where indicated, and imaging when the picture is not clear-cut.

Only then does the treatment discussion make sense. For many patients it ends with a medication adjustment. For those whose tremor has resisted medication, the choice usually lies between MRgFUS and DBS — and the deciding factor is most often whether one hand or both need treating.