Functional tremor.

Area of Science:

• Neurology
• Neuroscience
• Movement Disorders

Background:

• Functional tremor is the most frequent functional movement disorder.
• Clinical diagnosis relies on specific positive criteria, but can be challenging.
• Distinguishing from other conditions like Parkinson's disease may require further investigation.

Purpose of the Study:

• To outline the key clinical diagnostic criteria for functional tremor.
• To discuss the role of laboratory support and neuroimaging in diagnosis.
• To provide guidance for differentiating functional tremor from Parkinson's disease.

Main Methods:

• Review of established clinical diagnostic criteria for functional tremor.
• Discussion of ancillary investigations including laboratory tests.
• Consideration of neuroimaging techniques such as dopamine transporter single-photon emission computed tomography (DAT-SPECT).

Main Results:

• Positive clinical signs for functional tremor include sudden onset, unusual disease course, distractibility, entrainment, variability, and coactivation.
• Excessive exhaustion and other somatizations are common in patients.
• DAT-SPECT can be useful in rare cases to differentiate from Parkinson's disease.

Conclusions:

• Functional tremor diagnosis is often achievable through characteristic clinical findings.
• Laboratory support and specific imaging can enhance diagnostic certainty.
• Early and accurate diagnosis is crucial for appropriate patient management.