Health TrialsbyHealthPanel

The Role of Priors in Hallucinatory Perception in Parkinson's Disease

ConditionPARKINSON DISEASE (Disorder)
Trial statusRecruiting
Trial phaseNot listed
Trial typeObservational
Biological sexAll
Age18-85
SponsorUniversity Hospital, Grenoble

About this trial

The goal of this observational study is to better understand the mechanisms of hallucinations in patients with Parkinson's disease. The main question it aims to answer is:

Do prior expectations increase the rate of false perceptions during a visual stimulus detection task more in Parkinson's disease patients with visual hallucinations compared to those without?

Participants will undertake a computer task involving face detection and a battery of neuropsychological tests.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

Adults diagnosed with Parkinson's disease (with or without visual hallucinations) or healthy volunteers.

Age 18 - 85 years.

Consent to participate.

Disqualifiers

Currently participating in another clinical or therapeutic trial involving the testing of a drug treatment.

Diagnosis of dementia.

Trial population

The study will recruit Parkinson's disease patients (disease duration ≥1 year, no major cognitive impairment) from CHU Grenoble-Alpes, including 15 with minor hallucinations (e.g., passage/presence sensations) and 15 with major hallucinations (e.g., complex visual hallucinations). Patients with active psychosis are excluded. Healthy volunteers (matched by age, gender, and education) will be recruited via ads in senior associations and affiliated institutions (CHUGA, GIN). Matching tolerates ±5 years for age and ±2 years for education; those without a high school diploma will be matched without strict education criteria. Ads may also appear on institutional websites.

Trial design

Design model

Case-control

Time perspective

Prospective

Treatments tested in this trial

Not listed

Trial groups

60 Participants
are grouped into 3 trial groups
Group A: Hallucinations
Group B: No hallucinations
Group C: Control group

Trial outcomes

Primary outcomes

1

Effect of Prior Expectations on False Alarm Rates in Parkinson's Disease Patients With and Without Visual Hallucinations

The primary outcome measures the false alarm rate during a visual stimulus detection task, specifically the percentage of trials in which participants report perceiving a stimulus when none was presented. The study will assess whether prior expectations (cues indicating the likelihood of a stimulus) increase false alarm rates more in Parkinson's disease patients with visual hallucinations compared to those without. The primary statistical analysis will test for an interaction effect (p \< 0.05) between cue (prior expectation), stimulus presence, and group (patients with vs. without hallucinations) using a generalized linear mixed model.

Time frame
Baseline

Secondary outcomes

1

Comparison of False Alarm Rates Between Parkinson's Patients Without Hallucinations and Healthy Volunteers

This outcome will test whether prior expectations (cues) affect false alarm rates more in Parkinson's disease patients without hallucinations compared to healthy volunteers. The analysis will use a generalized linear mixed model to assess the presence of an interaction effect (p \< 0.05) between cue, stimulus presence, and group (patients without hallucinations vs. healthy controls).

Time frame
Baseline
2

Impact of Prior Expectations on Perceptual Confidence in Parkinson's Disease Patients With and Without Visual Hallucinations

This outcome will evaluate whether prior expectations (cues) influence confidence levels more in Parkinson's patients with hallucinations compared to those without. Confidence ratings will be analyzed only for trials where participants report detecting a stimulus. A generalized linear mixed model will test for an interaction effect (p \< 0.05) between cue, stimulus presence, and group (patients with vs. without hallucinations).

Time frame
Baseline
3

Neuropsychological Profile Differences Between Parkinson's Patients With and Without Hallucinations

This outcome will assess whether there are significant differences in neuropsychological test scores between Parkinson's patients with hallucinations and those without. The results will be interpreted while accounting for multiple comparisons using the False Discovery Rate (FDR).

Time frame
Baseline
4

Beta Power Differences in the Subthalamic Nucleus During False Alarms in Parkinson's Patients With Deep Brain Stimulation

This outcome will examine whether beta power (recorded via Medtronic's PERCEPT™ device) in the subthalamic nucleus differs between false alarm trials and other trials. Differences will be analyzed using a Student's t-test at each time point within a one-second window following stimulus presentation, with False Discovery Rate (FDR) correction applied to control for multiple comparisons.

Time frame
Baseline

Other outcomes

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

University Hospital, Grenoble

Lead sponsor

INSERM U1216 Grenoble Institut des Neurosciences

Collaborator

Source ClinicalTrials.gov
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