Sep 16, 2026
Patients have reduced activity in acetylcholine nerve cell network
Written by Steve Bryson, PhD | Aug. 20, 2026
- Parkinson’s patients experiencing visual hallucinations show reduced activity in the brain’s acetylcholine-using nerve cell network.
- Impaired early cholinergic signaling in specific brain regions can predict which patients will later develop visual hallucinations.
- Measuring cholinergic activity may serve as a biomarker for risk and a target for future therapeutic interventions.
People with Parkinson’s disease who experience visual hallucinations have reduced activity in the brain’s cholinergic system, a network of nerve cells that use the chemical messenger acetylcholine, a brain imaging study found.
Impaired cholinergic signaling in certain brain regions early on predicted who would later develop visual hallucinations.
The researchers said measuring cholinergic activity in certain brain regions could serve as a biomarker to identify patients at a higher risk of developing hallucinations, or as a target for future treatments aimed at reducing or preventing them.
The study, “Cholinergic deficits and hallucinations in Parkinson disease,” was published in npj Parkinson’s Disease.
Sep 15, 2026
Researchers urge monitoring of mental health and metabolic factors
Written by Andrea Lobo | Aug. 21, 2026
- A large study links early depressive symptoms to an increased risk of developing Parkinson’s, particularly for those with high genetic susceptibility.
- Metabolic changes involving fats appear to partly explain the connection between preclinical depression and Parkinson's disease risk.
- Monitoring depressive symptoms and metabolic factors may help identify high-risk individuals for earlier detection, per the researchers.
People with depressive symptoms may have higher odds of developing Parkinson’s disease, a large study suggests, with the researchers noting a potentially greater risk among those with stronger genetic susceptibility to the neurological condition.
The findings also point to changes in fat metabolism — one of several “metabolic disturbances” that the team says has been “independently associated with both depressive symptoms and [the development of Parkinson’s]” — as a possible link between the disease and these signs of depression. The researchers noted that “genetic factors also play a well-established role in [Parkinson’s] susceptibility.”
Overall, the study “demonstrates that even subthreshold depressive symptoms … are associated with a higher risk” of Parkinson’s, the researchers wrote. Still, the team noted that they could not definitively determine whether depression is a true independent risk factor for Parkinson’s or an early manifestation of the disease.
“Our results extend previous evidence linking clinical depression with [Parkinson’s] risk by focusing on preclinical depressive symptoms, which are more prevalent in the general population yet have been less studied in relation to [Parkinson’s],” the researchers wrote.
The study, “Association of pre-clinical depressive symptoms and its plasma metabolomic signature with Parkinson’s disease: a community-based longitudinal study,” was published in the journal Translational Psychiatry.
A progressive disease, Parkinson’s is caused by the loss of dopaminergic neurons, which are the nerve cells that produce dopamine, a brain signaling molecule involved in movement. In addition to its hallmark motor symptom of tremor, people with Parkinson’s may experience nonmotor symptoms, including mental health problems such as depression.
36% higher risk of Parkinson’s found with depressive disorders
Previous studies have also suggested that people diagnosed with depression may have a higher risk of developing Parkinson’s. However, it is less clear whether milder depressive symptoms preceding a formal diagnosis of depression may also be an early sign or risk factor for Parkinson’s.
In this study, researchers in China and Sweden aimed to clarify the extent to which depressive symptoms increase the risk of Parkinson’s development and whether this association varies according to genetic predisposition for the disease.
For that, they analyzed data from 451,922 people without Parkinson’s taking part in the UK Biobank, a large-scale biomedical database. Among the participants, 5.9% had a possible depressive disorder. That was defined as a score of three or higher on the two-item Patient Health Questionnaire, used by healthcare workers to screen and track the severity of mental health conditions such as depression and anxiety.
Those with possible depression were more likely to be younger, female, and of non-white race, the data showed. The researchers noted these individuals more frequently had less education, more irregular physical activity, and less sleep duration. They also were more likely to have other conditions such as diabetes, cardiovascular diseases, and a previous history of depression.
During a median follow-up of 14.6 years, 3,108 participants (0.7%) developed Parkinson’s: 194 who had possible depression and 2,914 who did not.
After adjusting for multiple factors, analyses showed that individuals with a possible depressive disorder had a 36% higher risk of developing Parkinson’s than those without.
Sep 14, 2026
Delaying rehab raised mortality risk regardless of disability level
Written by Andrea Lobo | Aug. 24, 2026
- Parkinson's disease involves the progressive loss of dopamine-producing neurons, leading to motor symptoms.
- Starting rehabilitation within the first year of a Parkinson's diagnosis may be linked to longer survival.
- Delaying rehabilitation is associated with a progressively higher risk of mortality across all disability levels.
Starting rehabilitation within the first year after a Parkinson’s disease diagnosis may be associated with longer survival, even among people who had already developed disability, a nationwide South Korean study found.
Delaying rehabilitation was associated with progressively higher mortality risk across all disability levels, including among people without functional impairment.
Researchers said these findings “indicate that the survival benefit of timely rehabilitation is not confined to the pre-disability stage; even among individuals with functional impairment, the prompt initiation of rehabilitation therapy remains meaningfully associated with improved long-term outcomes.”
The study, “Timing of rehabilitation therapy initiation and all-cause mortality in parkinson’s disease: nationwide cohort study,” was published npj parkinson’s disease.
Rehabilitation an important part of long-term Parkinson’s care
Parkinson’s is caused by the progressive loss of dopaminergic neurons, nerve cells that produce dopamine, a signaling molecule involved in movement. This leads to motor symptoms, such as tremors, slow movements, and balance and gait problems.
While medications can ease symptoms, they do not stop the disease from progressing, making rehabilitation an important part of long-term care. Guidelines recommend starting rehabilitation early, although in practice this is often delayed until people develop walking or balance problems. Whether starting rehabilitation early can affect patients’ long-term outcomes, including survival, remains unclear.
To learn more, researchers in South Korea used national health insurance data to examine whether the timing of rehabilitation after a Parkinson’s diagnosis was associated with the risk of death, and whether this association differed according to disability severity.
Sep 11, 2026
Study ties score derived from gene activity to cognitive changes, gait freezing
Written by Steve Bryson, PhD | Sept. 1, 2026
- Blood gene activity scores can effectively predict Parkinson’s complications like cognitive impairment and gait freezing, a study showed.
- Scores derived from inflammatory blood gene signatures independently correlated with risk of developing cognitive and movement issues.
- While these blood biomarkers show strong predictive value for long-term outcomes, external validation is needed.
A score derived from gene activity measured in blood samples can predict a higher risk of developing cognitive impairment and gait freezing in people with Parkinson’s disease, according to a study.
The findings demonstrate that gene activity signatures in blood capture aspects of Parkinson’s biology that are not fully explained by neurodegeneration, and may serve as potential biomarkers for cognitive impairment and freezing of gait (a brief, sudden inability to move), the researchers said.
The study, “Peripheral blood transcriptomic signature is associated with cognitive impairment and freezing of gait in Parkinson’s disease: a data-driven approach,” was published in npj Parkinson’s Disease.
Parkinson’s is marked by motor symptoms such as bradykinesia (slowed movement), rigidity, and tremor, along with a range of nonmotor symptoms. The disease varies considerably among patients, and its underlying biology involves several overlapping processes, including clumps of proteins called Lewy bodies, impaired cellular waste clearance, and inflammation.
Because of this complexity, scientists have struggled to identify reliable blood-based biomarkers for diagnosing Parkinson’s and for subtyping or predicting its course.
Sep 10, 2026
Cell study links abnormal LRRK2 activity to oxidative stress and ferroptosis
Written by Andrea Lobo | Sept. 4, 2026
- Parkinson’s-linked LRRK2 mutations were associated with abnormal iron buildup in neurons and astrocytes in laboratory cell models.
- The mutations were also linked to oxidative stress and lipid damage associated with ferroptosis, an iron-dependent form of regulated cell death.
- Experimental LRRK2 inhibition reduced excess iron and lipid peroxidation in the cell models, pointing to iron regulation as a potential therapeutic target.
Disease-causing mutations in the LRRK2 gene may disrupt iron regulation and promote cell damage, potentially contributing to the loss of dopamine-producing nerve cells in Parkinson’s disease, a study found.
The findings suggest that abnormal LRRK2 protein activity may contribute to iron accumulation inside cells and promote oxidative stress and processes linked to ferroptosis, an iron-dependent form of regulated cell death.
“What we discovered is that mutations in the LRRK2 gene directly change the way cells handle iron,” Matthew J. LaVoie, PhD, director of the University of Florida’s Center for Translational Research in Neurodegenerative Disease and one of the researchers who led the study, said in a press release.
LRRK2 mutations may link Parkinson’s to abnormal iron buildup
The study, “Parkinson’s disease LRRK2 mutations dysregulate iron homeostasis and promote oxidative stress and ferroptosis in human neurons and astrocytes,” was published in Molecular Neurodegeneration.
Parkinson’s disease is caused by the progressive loss of dopaminergic neurons, nerve cells that produce dopamine, a signaling molecule involved in motor control. These neurons are primarily found in a brain region called the substantia nigra.
Iron accumulation is thought to contribute to neuronal damage by promoting oxidative stress, an imbalance between harmful free radicals and the body’s antioxidant defenses, and ferroptosis. Mutations in LRRK2, among the most common genetic causes of Parkinson’s, have previously been linked to higher levels of iron in the substantia nigra.
However, how LRRK2 mutations affect iron regulation in human neurons and astrocytes, nerve-supporting cells that help regulate iron availability, and whether this contributes to neuronal damage, remain poorly understood.
“For the longest time, we’ve seen a correlation in living patients between iron deposition in affected regions of the brain and Parkinson’s disease, but we couldn’t understand it,” said study author Adam Mamais, PhD, a research assistant professor of neurology.
To investigate these questions, researchers used both patient-derived and gene-edited human induced pluripotent stem cell (iPSC) models carrying disease-causing LRRK2 mutations, including G2019S, R1441C, R1441G, and Y1699C, to study their effects on iron regulation. iPSCs are made by reprogramming adult cells into a stem cell-like state, after which they can be guided to develop into different cell types.
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