What Happens in the Brain in Parkinson's Disease
Parkinson's disease is a disorder of movement that begins in a tiny region deep in the brain called the substantia nigra. The cells here produce dopamine, a chemical messenger that lets different parts of the brain coordinate smooth, automatic movement. In Parkinson's, these dopamine-producing cells gradually die, and as dopamine levels fall, movement becomes slower, stiffer and harder to control.
What surprises many families is how much brain reserve is lost before any symptom shows. By the time a tremor or slowness first appears, roughly 60–80% of the dopamine cells in the substantia nigra have already been lost. The brain compensates silently for years, which is exactly why the disease can seem to arrive "suddenly" when in truth it has been developing quietly for a long time.
Inside the surviving cells, an abnormal clumping of a protein called alpha-synuclein forms deposits known as Lewy bodies. This process does not stay confined to the movement centre — it spreads to areas governing mood, sleep, smell and the gut, which explains why Parkinson's is far more than a tremor. Understanding this helps families see why symptoms are so varied, and why treatment focuses on replacing dopamine and protecting quality of life rather than simply steadying the hand.
Early Warning Signs — The Symptoms That Appear First
Some of the earliest signs of Parkinson's have nothing to do with tremor, and recognising them can lead to diagnosis years sooner. These "prodromal" symptoms reflect the disease affecting parts of the brain and body before the main movement centres are badly damaged.
Loss of smell
A reduced or absent sense of smell (hyposmia) is one of the earliest signs, sometimes appearing a decade before movement problems. Many people never notice it, or blame it on age or sinus trouble.
Constipation
Sluggish bowels are common in Parkinson's and often begin years early, because the same protein changes affect the nerves of the gut. Long-standing, unexplained constipation in an older adult is worth mentioning to a neurologist.
REM sleep behaviour disorder
Normally the body is paralysed during dreaming sleep. In this disorder, that safety switch fails and people physically act out their dreams — shouting, punching, kicking or falling out of bed. This is one of the strongest early warning signs and should always be assessed.
Small, cramped handwriting
Handwriting that becomes progressively smaller and more crowded across a line — called micrographia — is a classic subtle early motor sign. Family members often notice the change on cheques or notes before the person does.
None of these alone means Parkinson's, but several together in an older adult deserve a neurologist's assessment. Catching the disease early gives the most time to plan, treat and stay well.
The Motor Symptoms — Tremor, Stiffness, Slowness
The disease is defined clinically by a group of movement problems. Not everyone has all of them, and the mix varies from person to person.
Rest tremor
The most recognised sign is a rhythmic tremor that is worst at rest and eases when the hand is used — the opposite of many other tremors. It often starts on one side, in one hand, sometimes described as "pill-rolling" between thumb and fingers. Importantly, some people with Parkinson's never develop a noticeable tremor at all.
Rigidity (stiffness)
Muscles become stiff and resist movement, which can cause aching, a stooped posture and a feeling of being "tight". When the doctor moves the limb, it may feel like a ratchet clicking through the range — called cogwheel rigidity.
Bradykinesia (slowness)
This is the core feature — a general slowing and shrinking of movement. Buttoning a shirt, turning in bed or rising from a chair takes longer; the face becomes less expressive; the walk becomes shorter-stepped and shuffling, with reduced arm swing on one side.
Postural instability
In later stages, balance reflexes weaken, making falls more likely, particularly when turning or stepping backwards. Because falls are a major cause of injury, this symptom is treated seriously and is one reason exercise and balance training matter so much.
Non-Motor Symptoms — Often Worse Than Motor Symptoms
Families are often surprised to learn that the movement problems are only half the story. Many people find the non-motor symptoms harder to live with than the tremor, yet these are the symptoms most often overlooked and undertreated.
Mood and thinking: Depression and anxiety are common and are part of the disease itself, not merely a reaction to it. They respond well to treatment, so they should never be dismissed as "understandable sadness". Some people also experience slowed thinking, and a proportion develop memory difficulties over time.
Sleep: Beyond acting out dreams, people may have fragmented sleep, vivid dreams, restless legs and daytime sleepiness. Poor sleep worsens everything else, so it is always worth addressing.
Autonomic and other symptoms: Constipation, a drop in blood pressure on standing (causing dizziness), bladder urgency, excess saliva, reduced smell and fatigue all stem from the disease affecting the body's automatic systems. Each of these can be managed. A good neurologist treats the whole person — asking about mood, sleep and bowels, not just watching the hand — because that is what most improves daily life.
How Parkinson's Is Diagnosed
There is no single blood test or scan that proves Parkinson's disease. The diagnosis is clinical — made by an experienced neurologist based on the history and a careful examination. Dr. Iqbal Singh looks for the combination of slowness (bradykinesia) with either a rest tremor or rigidity, how the symptoms began (typically on one side), and how they progress. A strong, sustained response to Parkinson's medication also supports the diagnosis.
Scans are used mainly to rule out mimics rather than to confirm Parkinson's. An MRI of the brain is often done to exclude strokes, hydrocephalus or other conditions that can look similar. In selected cases where the diagnosis is genuinely uncertain — for example, distinguishing Parkinson's from essential tremor or drug-induced tremor — a specialised scan called a DaTSCAN can help. It uses a radioactive tracer to show whether the dopamine system is intact (normal) or depleted (as in Parkinson's).
Because the diagnosis rests on clinical skill, seeing a neurologist with real expertise matters. Conditions such as essential tremor, thyroid problems, side-effects of certain medications and normal-pressure hydrocephalus can all mimic Parkinson's — and some of these are fully reversible. Getting the diagnosis right at the start prevents years of wrong treatment.
Medications for Parkinson's — How Each Works
Parkinson's is one of the most treatable neurodegenerative diseases. The goal is to restore dopamine activity in the brain, and several classes of medicine do this in different ways. Treatment is tailored to age, symptoms and lifestyle.
Levodopa
Levodopa (given with carbidopa) is the most effective drug and the cornerstone of treatment. It is converted into dopamine in the brain, replacing what is missing. For most people it produces a remarkable improvement in slowness and stiffness. After several years, some develop response fluctuations ("wearing off") and involuntary movements (dyskinesias), which the neurologist manages by adjusting doses and timing. The old fear that levodopa should be "delayed as long as possible" is outdated — it is used when it improves life.
Dopamine agonists
These drugs (such as ropinirole and pramipexole) directly stimulate dopamine receptors. They are sometimes used in younger patients or added to levodopa. They can cause side-effects such as sleepiness, swelling and, occasionally, impulse-control problems (gambling, overspending), so patients and families are counselled to watch for these.
MAO-B inhibitors
Drugs such as rasagiline and selegiline slow the breakdown of dopamine in the brain, giving a modest but useful benefit, and are often used early or as an add-on. Other agents (COMT inhibitors, amantadine) are used in specific situations. The art of treatment lies in combining these thoughtfully — enough to move well, without overdoing it.
Exercise — The Most Powerful Non-Drug Intervention
If there were a single "treatment" beyond medication that every person with Parkinson's should take seriously, it would be exercise. A large and growing body of research shows that regular, vigorous exercise not only improves symptoms today but may actually slow the progression of the disease — something no drug has yet been proven to do.
Exercise works by encouraging the brain to adapt and rewire (neuroplasticity), improving how efficiently the remaining dopamine circuits work. Practically, it improves walking speed, balance, strength, mood and sleep, and reduces the risk of falls. The most beneficial programmes combine aerobic exercise (brisk walking, cycling), resistance training, and balance work, ideally started early and continued for life.
Because exercise is so central, Dr. Iqbal Singh discusses it at every visit, not as an afterthought. We cover this in depth in our companion guide on exercise for Parkinson's disease. The message for families is simple and hopeful: medication and movement together achieve far more than either alone.
Caring for Someone With Parkinson's — A Practical Guide for Families
Parkinson's is a journey the whole family walks together, and how a family responds makes an enormous difference to quality of life. The first principle is patience with pace — everything simply takes longer. Rushing a person with Parkinson's increases stress, freezing and falls; allowing extra time reduces all three.
Practical steps help enormously. Give medicines strictly on time, because Parkinson's drugs work in narrow windows and even a short delay can cause a distressing "off" period. Make the home safer by removing loose rugs, adding grab rails, improving lighting and keeping walkways clear to prevent falls. Encourage independence in daily tasks even when they are slow, as doing things maintains ability and dignity.
Watch for the quieter symptoms — low mood, poor sleep, constipation, swallowing difficulty and weight loss — and report them, because they are treatable and often matter more to daily comfort than the tremor. Do not neglect the carer, either: caregiver fatigue is real, and sharing the load and taking breaks is essential.
Finally, stay connected to your neurologist. Parkinson's care is not a one-off prescription but an ongoing partnership of adjusting treatment as needs change. At Gini we work with families over the long term, coordinating with physiotherapy and other specialists so that both the person and their carers are supported. You can read more about our approach on the Parkinson's and dementia care page.