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NCT Number: NCT05943652

Observational Study on "Functional Overlay" in Patients With Movement Disorders

The goal of this observational study is to learn about functional neurological disorders in patients with common non-functional movement disorders ("functional overlay"). The main questions it aims to answer are:

* What is the frequency of functional neurological disorders in patients with non-functional movement disorders (functional overlay)? * What are the characteristics of functional neurological disorders in patients with non-functional movement disorders?

Participants will be examined clinically and electrophysiologically, the examinations consist of:

* a neurological examination * neuropsychological testing * electrophysiological tremor diagnostic * questionnaires about psychological, biological and social risk factors

Researchers will compare patients with functional motor disorders to patients wit non-functional movement disorders to see if they differ from each other regarding the functional symptoms.

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Key information

Conditions

Conversion Disorder Basal Ganglia Diseases Brain Diseases Central Nervous System Diseases Dyskinesias Dystonia Mental Disorders Movement Disorders Nervous System Diseases Neurodegenerative Diseases Neurologic Manifestations Parkinson Disease Parkinsonian Disorders Pathological Conditions, Signs and Symptoms Signs and Symptoms Somatoform Disorders Synucleinopathies Tremor

Age range

18 year–18 year

Sex eligibility

All sexes

Study type

Observational

Primary location

About this study

Functional neurological disorders (FND) are common neurological disorders that are present in up to 16% of patients in neurological outpatient clinics. They are associated with a significant reduction in quality of life, can lead to permanent impairment, and have a poor prognosis, especially if the diagnosis is delayed.

FND have multifactorial causes and risk factors, including psychological stressors, childhood trauma, female gender, psychiatric disorders such as depression, anxiety disorder, or post-traumatic stress disorder, and other functional disorders such as irritable bowel syndrome or chronic pain syndrome. Patients with FND often report additional cognitive complaints ("cognitive fog").

A mismatch of various regulatory mechanisms, a disruption of sensory processing and motor output is assumed to be a central part of the pathogenesis. A characteristic feature of FND is a variability of symptoms according to attention. FND can be intensified by increased attention and weakened by distraction. Positive diagnostic criteria for FND have been established recently, so that by definition FND are no longer a diagnosis of exclusion.

The clinical presentations of FND are diverse and include impaired limb movement control, disturbances in vigilance that may be associated with seizures, and non-motor symptoms. FND often coincide and often coexist with pain, fatigue, sleep disorders, and cognitive disorders. Particularly non-motor functional symptoms are highly debilitating for patients.

The coincidence of "organic" neurological disorders and FND in the same patients ("functional overlay") is probably not uncommon, but has been investigated primarily in patients with Parkinson's Disease and epilepsy, so far. However, it is important to recognize FND in patients with movement disorders in order to treat them adequately and to protect them from incorrect treatment (surgery, unnecessary medication, etc.). However, the basic prerequisite for this is an exploration of the frequency and characteristics of the functional symptoms in movement disorders.

Who can participate

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Functional or non-functional movement disorder
  • 18 to 80 years

Exclusion criteria

  • Patient is not able to consent
  • Patient is not able to understand / speak German fluently (questionnaires are available only in German)

Treatment and study plan

Neurological Examination

Diagnostic Test

A neurological examination following a protocol to detect positive signs of functional neurological disorders.

Anamnesis

Diagnostic Test

A standardized question about the patient´s history. The response time is measured.

Question: "Could you tell me about the problems with the movement disorder you are experiencing?"

Neuropsychological testing

Diagnostic Test

Neuropsychological cognitive testing including:

  • Montreal Cognitive Assessment (MOCA)
  • Rey-Osterrieth Complex Figure Test (ROCFT)
  • Wechsler Memory Scale IV
  • Comprehensive Trail Making Test (CTMT)
  • semantic and phonematic fluency tests

Questionnaires

Diagnostic Test
  • Short Form 36 (SF 36)
  • Somatic Symptom Disorder - B Criteria Scale (SSD 12)
  • Patient Health Questionnaire 9 (PHQ 9)
  • Patient Health Questionnaire 15 (PHQ 15)
  • Generalized Anxiety Disorder 7 (GAD 7)
  • Fatigue Severity Scale (FSS)
  • Psychosomatic Competence Inventory (PSCI)
  • Work Ability Index (WAI)
  • Level of Personality Functioning Scale
  • Toronto Alexithymia Scale
  • Levels of Emotional Awareness Scale (short version)
  • Certainty About Mental States Questionnaire
  • Somatosensoric Amplification Scale
  • Personality Inventory for DSM-5 short version (PID5BF+M)
  • Childhood Trauma Questionnaire
  • European Quality of Life 5 Dimensions 5 Level Version (EQ5D5L)

Tremor recording

Diagnostic Test

Accelerometry following a standardized protocol, using a triaxial accelerometer transducer (Biometrics ACL300, Sensitivity 6 100 mV/G, Biometrics Ltd, UK)

Primary outcomes

  1. Functional neurological symptoms

    Time frame: on average 30 minutes

    Diagnosed by positive signs for functional neurological symptoms, as assessed in the neurological examination

Secondary outcomes

  1. Duration of anamnesis

    Time frame: 1 to 3 minutes

    Duration in seconds of the response to the question: "Could you tell me about the problems with the movement disorder you are experiencing?"

  2. Tremor diagnostic

    Time frame: up to 20 minutes

    Sum score of a electrophysiological test battery for psychogenic tremor, a scale from 0 to 10 with higher numbers indicating a higher probability for functional tremor

  3. Subjective quality of life

    Time frame: 5 minutes

    European Quality of Life 5 Dimensions 5 Level Version (EQ 5D 5L), results in a 5-digit number that describes the patient's health state

  4. Subjective health

    Time frame: up to 10 minutes

    Short Form 36 Questionnaire (SF-36), a 36 items questionnaires that results in 8 scales that describe the subjective health state of the patient, higher values indicating better health

  5. Fatigue

    Time frame: up to 5 minutes

    Fatigue severity scale (FSS): 9 item questionnaire with a 7 point Likert scale, higher values indicating more fatigue

  6. General anxiety

    Time frame: 3 minutes

    General anxiety disorder scale 7 (GAD-7): a 7 items questionnaire (0 to 21 points, higher values indicating more anxiety)

  7. Somatic symptoms

    Time frame: 5 minutes

    Patient health questionnaire 15 (PHQ 15): a 15 item questionnaire (0 to 30 points, higher values indicating more somatic symptoms)

  8. Depression

    Time frame: 3 minutes

    Patient health questionnaire 9 (PHQ 9): a 9 item questionnaire (0 to 27 points, higher values indicating more depressive symptoms)

  9. Psychosomatic Competence

    Time frame: up to 10 minutes

    Psychosomatic Competence Inventory (PSCI): a 44 items questionnaire with a 6 point Likert scale, resulting in 6 subscales, higher values indicate higher psychosomatic competence

  10. Work ability

    Time frame: 5 minutes

    Work ability index (WAI): 7 item questionnaire, 7 to 49 points, with higher values indicating better work ability

  11. Trauma in childhood

    Time frame: up to 10 minutes

    Child Trauma Questionnaire (CTQ): 28 items questionnaire, 5 point Likert scale, resulting in 5 subscales with 5 to 25 points, with higher values indicating more trauma experience

  12. Attachment styles

    Time frame: 5 minutes

    Experience of Close Relationships-Revised (ECR-RD 12): 12 items questionnaire with a 7 point Likert scale, resulting in 2 subscales

  13. Alexithymia

    Time frame: 5 minutes

    Toronto alexithymia scale (TAS): 26 items questionnaire with a 5 point Likert scale, higher values indicating more alexithymia

  14. Personality traits

    Time frame: up to 10 minutes

    The Personality Inventory for DSM-5 and ICD-11 Plus Modified (PID5BF + M): a 36 items questionnaire, with a 4 point Likert scale, resulting in 6 subscales

  15. Personality functioning

    Time frame: up to 15 minutes

    Levels of personality functioning scale (LPFS): a 80 items questionnaire, with a 4 point Likert scale, resulting in 4 subscales

  16. Executive function

    Time frame: up to 10 minutes

    Comprehensive trail making test (CTMT)

  17. Memory

    Time frame: up to 15 minutes

    Wechsler Memory Scale

  18. Visuospatial abilities

    Time frame: up to 15 minutes

    Rey-Osterrieth complex figure test

  19. Functional cognitive symptoms

    Time frame: up to 60 minutes

    Incongruence in cognitive tests

  20. Semantic word fluency

    Time frame: 2 minutes

    number of animals that can be listed in 2 minutes

  21. phonematic word fluency

    Time frame: 2 minutes

    number of words, that start with the letter "b", that can be listed in 2 minutes

Study contacts

Contact information is provided by the study sponsor or research team.

Daniela Kern, MD

CONTACT

[email protected]

004331638516051

Petra Schwingenschuh, MD

CONTACT

[email protected]

004331638583379

Sponsors and collaborators

Lead sponsor

Medical University of Graz

Other

Registry information

Official study title

Prevalence and Clinical Presentation of Functional Neurological Disorders in Patients With Movement Disorders - A Cross-sectional Study in the Movement Disorders Clinic of the Department of Neurology, Medical University of Graz

Important dates

Study start
2023
Primary completion
2025
Study completion
2026
First posted
Jul 13, 2023
Registry last updated
Sep 29, 2025

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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