What is Parkinson's disease?

Epidemiology and Anatomy

DLHA Staff Writer. 

Last reviewed: July 25, 2026

Introduction

Parkinson's disease is a brain disorder characterized by shaking or resting tremor in the fingers, head and/or voice, muscle stiffness, and difficulty with walking, balance and coordination.

Parkinson's symptoms usually begin gradually and get worse over time.

As the disease progresses, people may have difficulty initiating walking and talking. They may also have mental and behavioral changes, sleep problems, depression, memory difficulties, and fatigue.

Epidemiology

Both men and women can have Parkinson’s disease. However, the disease is one and one-half times more common in men than in women.

One clear risk factor for Parkinson's disease is age. Nearly 1% of the western population first develop the disease at about age 60. This rises to 4% by age 80 years [1]. The age-adjusted estimate for Sub-Sahara Africa (SSA) is lower than for Caucasians [2].  

In Caucasians, about 5 to 10 percent of people with Parkinson's have "early-onset" disease, which begins before the age of 50. Early-onset forms of Parkinson's are often, but not always inherited, and some forms have been linked to specific gene mutations. The role of heredity in the causation of the disease in sub-Saharan Africa (SSA) remains to be fully studied.

What area of the brain is affected?

The region of the brain affected in Parkinson’s disease is an area of the brain known as the basal ganglia plus its associated connection including the midbrain. The basal ganglia is responsible for regulating movement and coordination, motor learning, some executive functions and behaviour, as well as emotion..

Illustrative view of the half-brain showing where the basal ganglia is located and its components. Image credit: Shake It Up. Click on image to enlarge.

A major chemical neurotransmitters involved is sending signals to the basal ganglia from the midbrain is dopamine. Dopamine is produced predominantly in nerve cells located in a collection of cells in the midbrain called the Substantia nigra. These cells project their fibers to connect with other cells in the basal ganglia, which then connects with the thalamus to regulate coordination of motor movements.

Parkinson's disease is associated with degeneration of nerve cells in the midbrain resulting in low or inadequate production of dopamine.

Related: Parkinson's Disease Explained for Africans: Symptoms and Treatment

References:

1. How common is Parkinson’s disease? 

2. Epidemiology of Parkinsonism and Parkinson's disease in Sub-Saharan Africa: Nigerian profile

Published:September 23, 2019

Last reviewed: July 25, 2026.

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