Tremor
Tremor is one of the most common movement disorders and consists of a rhythmic, involuntary oscillation of one or more parts of the body. It can manifest at rest, while maintaining a posture, or during the execution of a voluntary movement. Tremor can be an expression of numerous neurological and non-neurological conditions, each with its own peculiar characteristics.
Tremor can have very diverse causes. Essential tremor is the most common form and has a strong genetic component, often involving autosomal dominant inheritance. In contrast, parkinsonian tremor is linked to nigrostriatal dopaminergic degeneration and the presence of alpha-synuclein aggregates. Other forms include dystonic tremor, cerebellar tremor (often resulting from cerebellar lesions or degeneration), enhanced physiological tremor (due to stress, medications, or hyperthyroidism), and neuropathic tremor (associated with peripheral neuropathies). Occasionally, the etiology remains unidentified.
Tremor is characterized by its frequency, amplitude, and the circumstances under which it appears.
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Essential tremor: Postural or kinetic, often bilateral, and predominant in the upper limbs; it can also involve the head and voice.
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Parkinsonian tremor: Typically occurs at rest, is asymmetrical, and is most evident in the hands (often described as “pill-rolling” or “coin-counting”).
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Cerebellar tremor: Low frequency and most pronounced during intentional movement (intention tremor).
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Dystonic tremor: Irregular and variable, often associated with dystonic postures.
Severity can vary with stress, emotions, fatigue, or caffeine consumption.
The diagnosis is clinical and is based on a detailed characterization of the tremor and the patient’s neurological context. A neurological examination allows for the differentiation between the main types. When necessary, the following are used:
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Blood tests (thyroid function, vitamin levels).
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Brain MRI for suspected cerebellar lesions.
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DaTSCAN SPECT in cases where the distinction between essential tremor and parkinsonian tremor is unclear.
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Electromyography (EMG) for the physiological analysis of the tremor.
Available therapies
Treatment depends on the specific type of tremor.
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Essential tremor: Beta-blockers, primidone, and topiramate; in refractory cases, Deep Brain Stimulation (DBS) of the ventral intermediate nucleus (VIM).
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Parkinsonian tremor: Dopaminergic medications (levodopa, agonists).
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Dystonic tremor: Targeted botulinum toxin injections.
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Cerebellar tremor: Limited therapeutic response; targeted rehabilitation.
Rehabilitative interventions (physiotherapy, occupational therapy, and writing aids) help improve daily functionality.
Research in progress
- Research is exploring new biomarkers to clinically distinguish between different types of tremor, the development of cellular models to identify pathogenic mechanisms, and advanced neuromodulation approaches. Genetic studies aim to clarify the basis of essential tremor and identify new responsible genes.
Reference laboratory
Contacts and informations
Dott. Alessio Di Fonzo
Mail: alessio.difonzo@policlinico.mi.it
Segreteria: elena.oriani@policlinico.mi.it