How Parkinson’s could be read in the brain, decades before tremors show up

For most people, Parkinson’s disease begins with a shake of the hand. But for neurologists across the world, tremor is no longer seen as the starting point. Growing evidence shows Parkinson’s may quietly take hold years, sometimes decades, earlier through symptoms that have nothing to do with movement.

Constipation, loss of smell, depression and disturbed sleep are now recognised as part of a long early phase of the neurodegenerative disease, often unfolding well before stiffness or slowness of movement appear. This period, known as the prodromal phase, reflects slow and progressive changes in the brain that remain largely invisible in routine clinical practice.