How does Parkinson’s cause speech difficulties?
ParkinsonDisease.net said: “PD causes damage to the nerves in the brain and in the body.
“The motor symptoms of PD, including speech changes, are caused by damage to the part of the brain called the substantia nigra pars compacta.
“The neurons (nerve cells) in the substantia nigra produce dopamine, a neurotransmitter (chemical messenger) that transmits signals from the substantia nigra to other parts of the brain to produce smooth, purposeful movement.
source: express.co.uk