Feel like you’re being watched? The bizarre Parkinson’s symptom that doctors often overlook

The unpleasant feeling of being watched when no one is around is an often overlooked symptom of early Parkinson’s, doctors say.

According to new research, between 40 and 50 percent of Parkinson’s patients experience these “presence hallucinations,” though doctors usually brush them off or chalk them up as side effects of medications.

But neuroscientists in Switzerland and Spain found that patients who experienced presence hallucinations early in the progression of their disease experienced faster, more severe cognitive decline after five years than those who didn’t.

Fosco Bernasconi, a scientist at the Swiss Ecole Polytechnique Federale de Lausanne (EPFL) Laboratory of Cognitive Neuroscience said“If you have Parkinson’s disease and experience hallucinations, even minor ones, you should share this information with your doctor as soon as possible.”

Symptoms can include uncontrollable tremors, slow movements and muscle stiffness, but experts say they often don’t appear until about 80 percent of the nerve cells are lost.

Parkinson’s disease is estimated to affect about one million Americans. The average age of onset is around 60, although early-onset Parkinson’s occurs in five to 10 percent of cases in people age 50 and younger.

The team of European neuroscientists wanted to determine how predictive early hallucinations are for deterioration in cognitive health.

Dr. Olaf Blanke, a neurologist from the EPFL and co-author of the study, said: ‘We now know that early hallucinations should be taken seriously in Parkinson’s disease.’

They investigated the influence that hallucinations had in 75 patients with Parkinson’s disease aged 60 to 70 years.

Each subject underwent a series of interviews with the experts to assess their level of cognitive impairment from the disease, as well as psychiatric interviews that gathered crucial information about their hallucinations.

The researchers also took measurements of the subjects’ brain activity at rest using an electroencephalogram (EEG), a test that records the patterns of electrical impulses between neurons using small metal discs called electrodes attached to the scalp. are confirmed.

EEGs are most commonly used to assess brain function and diagnose a variety of neurological conditions, such as epilepsy, Alzheimer’s disease, and sleep disorders. In this case, an EEG performed on resting Parkinson’s patients revealed certain abnormal patterns of brain wave activity.

Patients who experienced presence hallucinations were found to have “enhanced frontal theta oscillations,” meaning they had higher levels of oscillatory electrical activity in the frontal region of the brain, specifically in the theta frequency range.

Oscillating patterns of electricity in the brain are the result of billions of brain cells communicating with each other through electrical impulses. Different frequency bands – delta, theta, alpha, beta and gamma – are associated with different neurological processes.

The theta band, whose frequency ranges from four to eight hertz, is most closely associated with cognitive processes such as memory formation, learning, spatial awareness, and attention.

After five years, the researchers found that people who reported presence hallucinations early in their illness experienced faster cognitive decline in frontal executive function, which includes the range of skills we use every day to get through life, from attention and processing, the ability to plan for the future, problem-solving, and impulse control.

Dr. Bernasconi said: ‘So far we only have evidence linking cognitive decline and early hallucinations for Parkinson’s disease, but it could also be valid for other neurodegenerative diseases.’

While Parkinson’s usually affects the motor system the most — causing slow movements, stiffness of muscles and limbs, tremors, and instability in standing and walking — it also greatly affects a person’s memory, attention and processing speed, spatial orientation and depth perception. and executive functioning.

There’s no definitive cure for Parkinson’s disease, but an early diagnosis means more time to treat the symptoms, usually with medications that replenish a lack of dopamine in the brain, the neurotransmitter that dictates movement and fine motor skills.

But detecting the disease early can be challenging because many of Parkinson’s symptoms overlap with other conditions. Tremors, which often begin in one hand or foot and gradually spread to the other side of the body, are hallmark symptoms of Parkinson’s but may be mistaken for signs of a movement disorder called essential tremor.

Muscle stiffness and rigidity can be symptomatic of Parkinson’s disease, as well as more benign conditions such as muscle strains or arthritis, while slowness of movement (bradykinesia) can occur due to certain medications, vitamin deficiencies, or other movement disorders.

The research has been published in the journal Nature mental health.