Why Does My Left Index Finger Twitch?

A slight tremor of the finger, thumb or hand is one of the typical early warning symptoms of Parkinson’s disease, according to National Parkinson Foundation. Other signs include a twitching chin or lip, a trembling leg, difficulty in sleeping and moving, and constipation.

Shaking sometimes occurs after a vigorous exercise session, an injury or a medicine intake, notes National Parkinson Foundation. A person likely suffers from Parkinson’s disease if he notices trembling limbs when resting and experiences several other symptoms.

Unusually small handwriting is another early symptom of Parkinson’s disease, states National Parkinson Foundation. People with Parkinson’s disease often start to write in smaller handwriting in the first stages of the illness; however, changes in writing may normally occur as a person becomes older, especially when he suffers rigid fingers or hands or poor vision. Loss of smell that is not caused by a cold or flu may also indicate the onset of the disease.

Parkinsonian tremor, which starts in a single limb or on one part of the body, results from damage to areas of the brain that are responsible for controlling movement, says Healthline. It typically occurs after 60 years of age; however, not all tremors are dangerous as some people experience trembling when stressed, anxious or afraid. If a person develops a sudden, frequent tremor, he should see a health care professional immediately for diagnosis.