2023-06-30 14:15:19
Have you ever had the strong feeling that someone is behind you, so intense that you turn around, only to see that there is no one? It is a “hallucination of presence”.
Hallucinations of presence are especially common, although little known, in patients with Parkinson’s disease and may appear early in the disease. Sometimes the patient or the doctors do not give it importance, or they are considered a simple side effect of the medication.
Parkinson’s disease is traditionally defined as a movement disorder with typical motor symptoms of tremor at rest, rigidity, and others, but it also gives rise to a wide range of non-motor symptoms that appear early in the disease.
A team made up of, among others, Fosco Bernasconi and Olaf Blanke, from the Cognitive Neuroscience Laboratory at the Swiss Federal Institute of Technology, and in which the Hospital de Sant Pau in Barcelona and the Autonomous University of Barcelona (UAB) also collaborated, examined data from about 75 patients between the ages of 60 and 70, all of whom had been diagnosed with Parkinson’s disease. The study authors conducted a series of neuropsychological interviews with the patients to assess their cognitive status. Among the questions was whether or not they experienced hallucinations. In addition, electroencephalographic (EEG) measurements of resting brain activity were performed.
Analyzing the data, the scientists found that in patients with Parkinson’s disease, cognitive decline in frontal executive function is more rapid over the next 5 years for patients who early start experiencing the described class of hallucinations.
Early hallucinations in Parkinson’s disease are associated with frontal cognitive impairment (triangles), and are preceded by a specific frontal neural oscillation (theta frequency band). (Image: EPFL / Bernasconi. CC BY-SA)
Neurodegenerative diseases such as Parkinson’s are usually detected when they are already quite advanced, which limits the effect of preventive measures and therapies to mitigate the disease. Bernasconi, Blanke, and their colleagues set out to change this situation, looking for early signs (such as mild hallucinations) that help promote early intervention to slow the progression of the disease’s cognitive and psychiatric symptoms.
Hallucinations are among the lesser-known symptoms of Parkinson’s disease and are highly prevalent early in the disease, with one in two individuals experiencing hallucinations on a regular basis. The first of these hallucinations appear in one third of Parkinson’s patients before the onset of motor symptoms such as tremor.
The study is titled “Theta oscillations and minor hallucinations in Parkinson’s disease reveal decrease in frontal lobe functions and later cognitive decline”. And it has been published in the academic journal Nature Mental Health. (Source: NCYT from Amazings)
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