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

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

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.

Study Overview

• Status: Recruiting
• Conditions: Parkinson Disease; Dystonia; Conversion Disorder; Tremor
• Intervention / Treatment: Diagnostic test: Neurological examination; Diagnostic test: Anamnesis; Diagnostic test: Neuropsychological testing; Diagnostic test: Questionnaires; Diagnostic test: Tremor recording

Detailed Description

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.

• Study Type: Observational
• Enrollment (Estimated): 216

Contacts and Locations

• Study Contact: Name: Daniela Kern, MD; Phone Number: 004331638516051; Email: daniela.eibl@medunigraz.at
• Study Contact Backup: Name: Petra Schwingenschuh, MD; Phone Number: 004331638583379; Email: petra.schwingenschuh@medunigraz.at

Study Locations

• Austria
  • Styria
    • Graz, Styria, Austria, 8010
      • Recruiting
      • Medical University of Graz
      • Contact: Daniela Kern, MD; Phone Number: 004331638516051; Email: daniela.eibl@medunigraz.at

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: N/A

• Sampling Method: Non-Probability Sample

Study Population

Patients with functional and non-functional movement disorders of the Movement Disorders Outpatient Clinic of the Department of Neurology, Medical University of Graz

Description

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)

Study Plan

How is the study designed?

Number of groups / cohorts

6

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Parkinson Disease	Diagnostic test: Neurological examination; A neurological examination following a protocol to detect positive signs of functional neurological disorders.; Diagnostic test: Anamnesis; 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?"; Diagnostic test: Neuropsychological testing; 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; Diagnostic test: Questionnaires; 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); Diagnostic test: Tremor recording; Accelerometry following a standardized protocol, using a triaxial accelerometer transducer (Biometrics ACL300, Sensitivity 6 100 mV/G, Biometrics Ltd, UK)
Idiopathic Dystonia	Diagnostic test: Neurological examination; A neurological examination following a protocol to detect positive signs of functional neurological disorders.; Diagnostic test: Anamnesis; 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?"; Diagnostic test: Neuropsychological testing; 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; Diagnostic test: Questionnaires; 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); Diagnostic test: Tremor recording; Accelerometry following a standardized protocol, using a triaxial accelerometer transducer (Biometrics ACL300, Sensitivity 6 100 mV/G, Biometrics Ltd, UK)
Essential Tremor	Diagnostic test: Neurological examination; A neurological examination following a protocol to detect positive signs of functional neurological disorders.; Diagnostic test: Anamnesis; 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?"; Diagnostic test: Neuropsychological testing; 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; Diagnostic test: Questionnaires; 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); Diagnostic test: Tremor recording; Accelerometry following a standardized protocol, using a triaxial accelerometer transducer (Biometrics ACL300, Sensitivity 6 100 mV/G, Biometrics Ltd, UK)
Functional Neurological Disorder	Diagnostic test: Neurological examination; A neurological examination following a protocol to detect positive signs of functional neurological disorders.; Diagnostic test: Anamnesis; 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?"; Diagnostic test: Neuropsychological testing; 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; Diagnostic test: Questionnaires; 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); Diagnostic test: Tremor recording; Accelerometry following a standardized protocol, using a triaxial accelerometer transducer (Biometrics ACL300, Sensitivity 6 100 mV/G, Biometrics Ltd, UK)
Functional Cognitive Disorder	Diagnostic test: Neurological examination; A neurological examination following a protocol to detect positive signs of functional neurological disorders.; Diagnostic test: Anamnesis; 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?"; Diagnostic test: Neuropsychological testing; 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; Diagnostic test: Questionnaires; 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); Diagnostic test: Tremor recording; Accelerometry following a standardized protocol, using a triaxial accelerometer transducer (Biometrics ACL300, Sensitivity 6 100 mV/G, Biometrics Ltd, UK)
Alzheimer Disease	Diagnostic test: Neurological examination; A neurological examination following a protocol to detect positive signs of functional neurological disorders.; Diagnostic test: Anamnesis; 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?"; Diagnostic test: Neuropsychological testing; 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; Diagnostic test: Questionnaires; 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); Diagnostic test: Tremor recording; Accelerometry following a standardized protocol, using a triaxial accelerometer transducer (Biometrics ACL300, Sensitivity 6 100 mV/G, Biometrics Ltd, UK)

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Functional neurological symptoms	Diagnosed by positive signs for functional neurological symptoms, as assessed in the neurological examination	on average 30 minutes

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Duration of anamnesis	Duration in seconds of the response to the question: "Could you tell me about the problems with the movement disorder you are experiencing?"	1 to 3 minutes
Tremor diagnostic	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	up to 20 minutes
Subjective quality of life	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	5 minutes
Subjective health	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	up to 10 minutes
Fatigue	Fatigue severity scale (FSS): 9 item questionnaire with a 7 point Likert scale, higher values indicating more fatigue	up to 5 minutes
General anxiety	General anxiety disorder scale 7 (GAD-7): a 7 items questionnaire (0 to 21 points, higher values indicating more anxiety)	3 minutes
Somatic symptoms	Patient health questionnaire 15 (PHQ 15): a 15 item questionnaire (0 to 30 points, higher values indicating more somatic symptoms)	5 minutes
Depression	Patient health questionnaire 9 (PHQ 9): a 9 item questionnaire (0 to 27 points, higher values indicating more depressive symptoms)	3 minutes
Psychosomatic Competence	Psychosomatic Competence Inventory (PSCI): a 44 items questionnaire with a 6 point Likert scale, resulting in 6 subscales, higher values indicate higher psychosomatic competence	up to 10 minutes
Work ability	Work ability index (WAI): 7 item questionnaire, 7 to 49 points, with higher values indicating better work ability	5 minutes
Trauma in childhood	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	up to 10 minutes
Attachment styles	Experience of Close Relationships-Revised (ECR-RD 12): 12 items questionnaire with a 7 point Likert scale, resulting in 2 subscales	5 minutes
Alexithymia	Toronto alexithymia scale (TAS): 26 items questionnaire with a 5 point Likert scale, higher values indicating more alexithymia	5 minutes
Personality traits	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	up to 10 minutes
Personality functioning	Levels of personality functioning scale (LPFS): a 80 items questionnaire, with a 4 point Likert scale, resulting in 4 subscales	up to 15 minutes
Executive function	Comprehensive trail making test (CTMT)	up to 10 minutes
Memory	Wechsler Memory Scale	up to 15 minutes
Visuospatial abilities	Rey-Osterrieth complex figure test	up to 15 minutes
Functional cognitive symptoms	Incongruence in cognitive tests	up to 60 minutes
Semantic word fluency	number of animals that can be listed in 2 minutes	2 minutes
phonematic word fluency	number of words, that start with the letter "b", that can be listed in 2 minutes	2 minutes

Collaborators and Investigators

• Sponsor: Medical University of Graz

Study record dates

Study Major Dates

• Study Start (Actual): January 1, 2023
• Primary Completion (Estimated): December 31, 2025
• Study Completion (Estimated): June 30, 2026

Study Registration Dates

• First Submitted: July 5, 2023
• First Submitted That Met QC Criteria: July 5, 2023
• First Posted (Actual): July 13, 2023

Study Record Updates

• Last Update Posted (Estimated): September 29, 2025
• Last Update Submitted That Met QC Criteria: September 23, 2025
• Last Verified: September 1, 2025

More Information

Terms related to this study

• Keywords: Accelerometry; Neuropsychology; Patient Health Questionnaire
• Additional Relevant MeSH Terms: Synucleinopathies; Neurologic Manifestations; Brain Diseases; Central Nervous System Diseases; Nervous System Diseases; Mental Disorders; Neurodegenerative Diseases; Movement Disorders; Parkinsonian Disorders; Basal Ganglia Diseases; Dyskinesias; Somatoform Disorders; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Parkinson Disease; Tremor; Dystonia; Conversion Disorder; Diagnostic Techniques and Procedures; Diagnosis; Diagnostic Techniques, Neurological; Physical Examination; Immune System Phenomena; Immunity; Adaptive Immunity; Neurologic Examination; Immunologic Memory
• Other Study ID Numbers: 34-509 ex 21/22

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No