Khaberni - A recent study revealed that exposure to loud noise for just one hour daily can exacerbate symptoms of a chronic neurological disease.
In the study, researchers from China conducted an experiment on genetically modified mice that were in the early stages of Parkinson's disease, a degenerative neurological disorder resulting from the death of dopamine-producing neurons in the brain. Patients typically suffer from limb tremors, muscle stiffness, and problems with speech and balance, symptoms that progressively worsen over time.
The mice were subjected to sounds ranging from 85 to 100 decibels — equivalent to the noise of a lawn mower or an electric mixer — either in short pulses or daily repeated exposure.
The results showed that just one hour of exposure was enough to cause a slowdown in movement and loss of balance compared to the mice not exposed to the noise. Mice that underwent the experiment for an hour daily over a week showed chronic movement disorders that persisted even after the noise exposure stopped.
The researchers found that an area in the brain known as the inferior colliculus — responsible for processing sound — is directly connected to the substantia nigra, the part responsible for dopamine production and severely affected in Parkinson's disease.
The analysis showed that chronic stimulation of the inferior colliculus leads to the death of dopamine-producing cells and reduced levels of a protein called vesicular monoamine transporter 2 (VMAT2), which is responsible for transporting neurotransmitters such as dopamine and serotonin within the neurons.
Conversely, the team found that inhibiting activity of the inferior colliculus increased the production of this protein, which could help reverse the effects of noise in mice with the disease in its early stages.
The researchers noted that these findings highlight the potential role of environmental factors, such as noise and pollution, in accelerating the progression of Parkinson's disease, although the study was only conducted on animals.
The research team wrote: "It was striking to observe how exposure to environmental noise leads to degeneration of dopamine-producing neurons and associated motor deficits, providing new insights into the non-genetic factors that cause Parkinson's disease."
Although there is no definitive cure for Parkinson's disease yet, medications and supportive treatments help compensate for the lack of dopamine and alleviate symptoms. Levodopa is the most commonly used drug, crossing the blood-brain barrier to convert to dopamine, which improves balance and reduces tremors.
