neurodegenerative diseases

A Danish study published in JAMA Neurology found an association between long-term exposure to residential road traffic noise and an increased risk of developing Parkinson's disease. The study followed more than three million Danish adults aged 40 years and older for 18 years using data from Denmark's national administrative and health registries. The researchers assessed residential road traffic noise exposure at both the most exposed and the least exposed façades of participants' homes. The study also found that individuals with a quiet façade had a lower risk of developing Parkinson's disease than those whose homes were exposed to high levels of noise on all sides.

A new study reveals that the proportion of adults with dementia has risen significantly in Mexico, Peru and Puerto Rico over the last two decades, rising from one in ten older adults to almost one in six; a trend that runs counter to that seen in the US and other wealthy countries. Rates remained stable in Cuba and the Dominican Republic. The authors urge investment in prevention, dementia screening and care infrastructure. The study is published in JAMA Neurology.

A team from the United States analyzed blood levels of three biomarkers associated with Alzheimer’s disease in 1,350 people without dementia, with an average age of 61. Higher levels were associated with poorer cognitive performance five years later, leading the authors to state that the findings “demonstrate the potential for early detection of Alzheimer’s disease in middle-aged adults through blood tests.” In a related commentary, two experts who did not participate in the study state that, in young populations without cognitive impairment, these tests “may generate a higher rate of false positives” and caution that “they are not suitable for mass, non-selective screening for Alzheimer’s disease pathology in cognitively healthy populations or in the general community.” The study is published in The Lancet.

A lightweight robotic device aids neuromuscular recovery in children with spinal muscular atrophy, helping them to stand unaided, according to a study published in Nature. The research involved six participants aged between six and 10 and shows that the device achieved significant improvements in lower limb motor function after six weeks of assisted training. The study highlights that the improvement persists after training is discontinued and conventional physiotherapy routines are resumed, demonstrating the potential for lasting recovery.  

A new study conducted over 25 years with data from 2,766 older women, who were in good cognitive health at the start, shows that high blood levels of the p-tau217 protein were strongly associated with future mild cognitive impairment and dementia. In its press release, the University of California (United States), where the authors work, stated that ‘a new blood biomarker can predict a woman's risk of developing dementia up to 25 years before symptoms appear.’ The study is published in the journal JAMA Network Open.

The journal Nature Medicine has published the results of the phase III STEER clinical trial for the treatment of spinal muscular atrophy in children aged between two and 18 years. A single dose of gene therapy administered directly into the cerebrospinal fluid showed an improvement in motor function in the children who received it in the clinical trial (75 compared to 51 with placebo). The drug in question is onasemnogene abeparvovec. On 24 November, the US Food and Drug Administration approved this treatment under the trade name Itvisma, from Novartis, based on data from this trial, making it the first treatment available for children over two years of age.

Physical inactivity is a risk factor for the onset of Alzheimer's disease. An international team has studied nearly 300 people with preclinical Alzheimer's—without symptoms but with an accumulation of tau and beta-amyloid proteins in the brain—for 14 years to find out whether physical exercise can also influence its progression. The results indicate that even very moderate activity—walking between 3,000 and 5,000 steps per day—was associated with slower deterioration, while the benefits—which appear to be related to lower tau protein deposits—were greater and tended to stabilise with activity involving between 5,000 and 7,500 steps. The results are published in the journal Nature Medicine.

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterised by progressive loss of motor neurons. An international team has discovered evidence that ALS may have an autoimmune component, meaning that the immune system mistakenly attacks healthy cells, a hypothesis that had been considered by the scientific community. The study shows that inflammatory immune cells—called CD4+ T cells—attack certain proteins that are part of the nervous system in people with ALS. ‘These findings highlight the potential of therapeutic strategies aimed at improving regulatory T cells,’ the authors note in the research, published in Nature.

An international team with Spanish participation has analyzed data from more than 500,000 people and found a link between digestive disorders such as colitis, gastritis, esophagitis, or functional bowel disorders and an increased risk of developing Alzheimer's and Parkinson's diseases. According to the researchers, who published their findings in the journal Science Advances, “this effort sheds light on the interaction between factors involved in the gut-brain axis and opens avenues for targeted treatment and early diagnosis.”