Parkinson's disease (PD), a neurodegenerative illness that worsens over time is usually identified by tremors, stiffness of the muscles, and slowness of movement. Yet lesser understood, as well as under-publicized, are the lesser-motorized, less-documented symptoms which manifest years in advance of the signature ones. Learning to detect these subtle warnings can facilitate earlier detection and enhance patients' quality of life.

More than 10 million people globally have Parkinson's disease, according to the Parkinson's Foundation. PD affects an estimated 6-53 per 100,000 people in India and is likely to increase sharply owing to a growing elderly population.

1. Loss of smell (Hyposmia): One of the earliest signs of Parkinson’s are a reduced sense of smell, known as hyposmia. Studies suggest that up to 90% of individuals with Parkinson’s experience some level of olfactory dysfunction often years before motor symptoms appear. Many dismiss it as a minor inconvenience or age-related change, delaying diagnosis.

2. Constipation: Chronic constipation occurs in over 60%-80% of Parkinson's patients and is becoming accepted as a possible early warning sign. The slowing of the digestive system results from degeneration of nerve endings within the digestive tract, something that can develop many years prior to brain-based symptoms.

3. Sleep disturbances: Parkinson's can profoundly affect sleep, even before diagnosis has been made. A condition known as REM sleep behavior disorder (RBD) in which people physically act out their dreams has been identified in more than 30% of individuals who go on to develop Parkinson's. Insomnia, hypersomnolence (excessive daytime sleepiness), and restless legs syndrome also occur frequently, but are under-reported.

4. Depression and anxiety: Mental health changes are not a response to Parkinson's but are part of the disease process. Research indicates that 40–50% of patients experience depression or anxiety before motor symptoms are apparent. Dopamine imbalance in the brain leads to emotional dysregulation, and clinicians must consider psychiatric symptoms as possible early indicators.

5. Voice and facial changes: Soft, low voice (hypophonia) and decreased facial expression (masked face) are subtle yet revealing signs. Friends or family members might recognize the individual is speaking more quietly or appears unemotional. While usually dismissed as shyness or exhaustion, these symptoms can be manifestations of the initial neuromuscular effect of Parkinson's.

6. Micrographia: This is a change in writing letters get smaller and more compact. Micrographia may be an early motor sign but is often missed unless specifically sought out. It illustrates bradykinesia, slowness of movement characteristic in PD.

Though these symptoms by themselves appear unrelated or trivial, their association particularly in those over 60 is of concern. The mean delay from the initial appearance of early non-motor symptoms to diagnosis can be as long as 5 years. Such a delay diminishes the opportunity for early intervention, which potentially could decelerate disease progression.

Increased awareness of these more subtle symptoms has the potential to empower patients and physicians to identify Parkinson's sooner. With ongoing research into disease-modifying treatments, developing early detection will be critical to enhancing outcomes and living independently longer.

Dr. Anish Mehta, Consultant - Department of Neurology & Movement Disorders, Ramaiah Institute of Neurosciences, Ramaiah Memorial Hospital