Exploratory Study on the Role of Prior Expectations in Hallucinatory Perceptions
概览
- 阶段
- 不适用
- 状态
- 尚未招募
- 发起方
- University Hospital, Grenoble
- 入组人数
- 60
- 试验地点
- 1
- 主要终点
- Effect of Prior Expectations on False Alarm Rates in Parkinson's Disease Patients With and Without Visual Hallucinations
概览
简要总结
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.
详细描述
Understanding why hallucinations happen in Parkinson's disease is crucial for improving the daily lives and care of those affected. Hallucinations are common non-movement symptoms in Parkinson's that can significantly impact how people function, increase the burden on caregivers, and may signal faster cognitive decline.
Research shows that what we perceive isn't just based on what our senses pick up-it's also shaped by our expectations and past experiences. Sometimes, over-relying on these expectations can lead to hallucinations. However, it's still unclear whether this explains why some people with Parkinson's experience hallucinations while others don't.
In cognitive science, one way to study hallucinations is by showing people repeated trials where a stimulus is either barely visible or not present at all. The number of times someone reports seeing something when nothing is actually there (called "false alarms") has been linked to the likelihood of experiencing hallucinations in everyday life.
To explore this further, researchers use cues that hint at whether a stimulus is likely to appear. Studies have shown that healthy individuals use these cues to guide their perception. Some research even suggests that people with Parkinson's might rely on these cues more strongly, but this hasn't been directly connected to hallucinations yet.
Our study aims to test whether these cues-by shaping expectations-affect the rate of false alarms more in Parkinson's patients who experience hallucinations compared to those who don't. By understanding why false alarms happen, deeper insights will be gained into visual hallucinations, as well as improved early detection, and ultimately enhanced care.
To better understand the brain mechanisms involved, brain activity will be recorded from patients who have deep-brain stimulation electrodes that allow us to measure neural signals in a specific brain area called the subthalamic nucleus. This could help us uncover how the brain processes these expectations and perceptions.
研究设计
- 研究类型
- Observational
- 观察模型
- Case Control
- 时间视角
- Prospective
入排标准
- 年龄范围
- 18 Years 至 85 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •Adults diagnosed with Parkinson's disease (with or without visual hallucinations) or healthy volunteers.
- •Age 18 - 85 years.
- •Consent to participate.
排除标准
- •Currently participating in another clinical or therapeutic trial involving the testing of a drug treatment.
- •Inability to perform cognitive tests due to:
- •Non-psychiatric (somatic) conditions likely to affect cognitive abilities. Peripheral sensory or motor deficits. Acute clinical conditions (e.g., agitation, impaired consciousness).
- •Diagnosis of dementia.
- •Individuals covered by Articles L1121-5 to L1121-8 of the French Public Health Code (Code de la Santé Publique), including:
- •Pregnant women, women in labor, or breastfeeding mothers. Individuals deprived of liberty by judicial or administrative decision. Individuals receiving psychiatric care under Articles L. 3212-1 and L. 3213-1 (excluding those covered by Article L. 1121-8).
- •Individuals admitted to a healthcare or social institution for purposes other than research.
- •Minors or adults under legal guardianship or unable to express consent.
- •\- Individuals with a hierarchical relationship to any professional involved in the study.
- •Only for healthy volunteers:
研究组 & 干预措施
Hallucinations
Patients with Parkinson's disease with hallucinations
No hallucinations
Patients with Parkinson's disease without hallucinations
Control group
Age and sex matched group of healthy participants
结局指标
主要结局
Effect of Prior Expectations on False Alarm Rates in Parkinson's Disease Patients With and Without Visual Hallucinations
时间窗: Baseline
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.
次要结局
- Comparison of False Alarm Rates Between Parkinson's Patients Without Hallucinations and Healthy Volunteers(Baseline)
- Impact of Prior Expectations on Perceptual Confidence in Parkinson's Disease Patients With and Without Visual Hallucinations(Baseline)
- Neuropsychological Profile Differences Between Parkinson's Patients With and Without Hallucinations(Baseline)
- Beta Power Differences in the Subthalamic Nucleus During False Alarms in Parkinson's Patients With Deep Brain Stimulation(Baseline)