REFERENCE · DIAGNOSTIC TECHNIQUE

Distractibility in Functional Tremor

Purpose and Suitability
Anatomy and Physiology
Preparation and Examination
Interpretation and Explanation
Evidence and Limitations
Media and Accessibility
Research and Sources

Purpose and Suitability

Distractibility is a change in tremor while attention is engaged in another task. A clinician compares the same shaking limb before, during and after that task. The tremor may lessen, pause or change its rhythm. The clinical question is whether a clear, task-linked contrast contributes to the diagnosis. [2]

This page describes a bedside comparison, mainly for visible limb tremor. It is distinct from entrainment, where the tremor follows the other limb’s rhythm, and from the specifically recorded ballistic-movement test.

If there is no tremor to compare, or the second task cannot be performed, this particular observation may be unavailable. It is not a home test or an instruction to keep someone distracted throughout the day.

Purpose and Suitability
Anatomy and Physiology
Preparation and Examination
Interpretation and Explanation
Evidence and Limitations
Media and Accessibility
Research and Sources

Anatomy and Physiology

The visible hand movement is the result of muscle activity acting across joints. At the wrist, flexors bend the hand toward the palm side and extensors move it back. Surface EMG can record muscle activity, while a movement sensor records the shaking itself. These signals answer different questions. [2]

Surface EMG (electromyography): Recording electrical activity from muscles using electrodes on the skin.

Attention is part of how movement is organized. Huys and colleagues studied movement and visual feedback in selected people with functional action tremor and comparison groups. Their findings support an altered attentional focus on ongoing movement feedback. Participants were selected partly for clinical distractibility; the experiment therefore does not independently validate distractibility as a diagnostic test. [3]

A task-related change is an observation. It does not identify the original cause of the tremor or establish what happens in every person’s brain.

Purpose and Suitability
Anatomy and Physiology
Preparation and Examination
Interpretation and Explanation
Evidence and Limitations
Media and Accessibility
Research and Sources

Preparation and Examination

Explain the purpose and obtain consent: “I would like to compare the shaking while you do another task. Tell me if you need a pause.” Choose a comfortable, supported position. Ask about pain, fatigue and communication or sensory needs before selecting the task.

The outline below describes the bedside comparison. The IFCN review explains how related tasks are recorded in laboratory assessment. [2]

Describe the baseline. Observe the tremor in the position or activity where it is present. Note the limb, support, posture, size and rhythm of movement.
Choose one manageable second task. An example is a short counting task, or a simple tapping sequence with the less affected hand. Explain it first and check understanding. Avoid a task whose language or calculation demands overwhelm the person.
Keep the original comparison clear. Watch the tremulous limb while the person performs the other task. Note any change in support, grip or posture that could itself change the movement.
Describe what changed. Did shaking stop, become smaller, slow, speed up or become irregular? Record how the person performed the second task as well.
Return to the baseline condition. Observe what happens when the second task ends. Repeat only as needed to judge a usable pattern; stop for pain, marked fatigue, distress or a request to stop.
Integrate and explain. Record the contrast with the wider examination. If there is no interpretable comparison, document why rather than treating it as a negative test.

Any adaptation should be recorded. An accessible alternative can help the clinical conversation, but an altered task does not automatically inherit a published protocol’s accuracy.

Purpose and Suitability
Anatomy and Physiology
Preparation and Examination
Interpretation and Explanation
Evidence and Limitations
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Interpretation and Explanation

A clear, repeatable change may support functional tremor. Ordinary fluctuation, altered posture, mechanical support and changes in task demand also require consideration. An absent change does not rule out functional tremor. [1][2]

A practical way to document the result is to describe a supportive change, no supportive change during an adequate comparison, or an uninterpretable comparison and the reason for it.

An authored example explanation is: “Your hand shook less while you were doing the other task. That change helps us understand the movement pattern. We also need to understand what happens when you eat, dress or use your hand repeatedly.”

The finding can inform a rehabilitation discussion. It does not measure daily independence, endurance or support needs. Link the observation to the person’s priorities and the everyday-function assessment, rather than assuming that the same change is available on demand.

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Anatomy and Physiology
Preparation and Examination
Interpretation and Explanation
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Evidence and Limitations

The 2026 meta-analysis brings together ten studies of electrophysiological testing. Results varied across methods. Test batteries performed comparatively well, while mental-task frequency measures need further evaluation. These findings support a structured laboratory assessment; they do not supply an accuracy figure for every bedside distraction task. [6]

The 2016 prospective validation included 38 people with functional tremor and 73 with other tremors, with raters blinded to the clinical diagnosis. The complete battery had 89.5% sensitivity and 95.9% specificity at its predefined threshold. [5]

Sensitivity: How often a test detects the condition in people who have it. Specificity: How often it is negative in people without the condition.

The earlier 2011 development study compared 13 functional and 25 other tremors. Some comparison tremors also changed during tasks, which helps explain why the pattern across several observations matters. [4]

Purpose and Suitability
Anatomy and Physiology
Preparation and Examination
Interpretation and Explanation
Evidence and Limitations
Media and Accessibility
Research and Sources

Media and Accessibility

A useful clinician-led video would show both the tremulous limb and the second task continuously, including the return to baseline. Keep instructions audible and provide captions and a transcript. Describe the observed change without declaring a diagnosis from the clip alone.

Agree recording and public-use consent separately from examination consent. Avoid startling tasks, flashing cues, uncomfortable sound or repeated attempts to obtain a dramatic change. The written explanation should remain complete for readers who cannot comfortably watch movement videos.

Purpose and Suitability
Anatomy and Physiology
Preparation and Examination
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Media and Accessibility
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Research and Sources

Read the IFCN clinical review for interpretation and the 2026 meta-analysis for diagnostic evidence. Functional tremor is involuntary; a change with attention helps explain movement control. The earlier studies below contribute specific observations within that clinical understanding. [2]

Citation	Figure	Full citation
[1]	—	Bartl M, Kewitsch R, Hallett M, Tegenthoff M, Paulus W. Diagnosis and therapy of functional tremor: a systematic review illustrated by a case report. Neurological Research and Practice. 2020;2:35. FND-CIT-0019.
[2]	—	Edwards MJ, Koens LH, Liepert J, Nonnekes J, Schwingenschuh P, van de Stouwe AMM, Morgante F. Clinical neurophysiology of functional motor disorders: IFCN Handbook Chapter. Clinical Neurophysiology Practice. 2024;9:69–77. https://doi.org/10.1016/j.cnp.2023.12.006 FND-CIT-0022.
[3]	—	Huys ACML, Haggard P, Bhatia KP, Edwards MJ. Misdirected attentional focus in functional tremor. Brain. 2021;144(11):3436–3450. DOI. Full text. FND-CIT-0220.
[4]	—	Schwingenschuh P, Katschnig P, Seiler S, et al. Moving toward “laboratory-supported” criteria for psychogenic tremor. Movement disorders : official journal of the Movement Disorder Society. 2011;26(14):2509-2515. FND-CIT-0177.
[5]	—	Schwingenschuh P, Saifee TA, Katschnig-Winter P, et al. Validation of “laboratory-supported” criteria for functional (psychogenic) tremor. Movement disorders : official journal of the Movement Disorder Society. 2016;31(4):555-562. DOI. PMID: 26879346. FND-CIT-0178.
[6]	—	Rujirussawarawong S, Ounmuang C, Aungsumart S, Kasemsuk C, Limotai N. Electrophysiology in distinguishing functional tremor from organic tremor: a systematic review and meta-analysis of diagnostic accuracy. Movement Disorders Clinical Practice. Published online June 11, 2026. DOI. PubMed. FND-CIT-0224.

Purpose and Suitability
Anatomy and Physiology
Preparation and Examination
Interpretation and Explanation
Evidence and Limitations
Media and Accessibility
Research and Sources