A tremor or slight shaking in the finger, thumb, hand, arm, jaw, foot, or chin is usually one of the first warning signs of Parkinson’s disease. More often than not, it affects only one limb or one side of the body to start, then spreads to other parts of the body over time. The tremor will be most noticeable to the sufferer at rest, but will become noticeable to others as the condition progresses and the shaking worsens. Another early indicator of Parkinson’s disease is a change in handwriting, namely a decrease in size. The medical term for small handwriting is micrographia, and it’s due to changes in the brain that make writing and other fine motor skills more difficult. The handwriting will look cramped, the individual letters will be smaller than normal, and the words will be spaced closely.
In addition to writing changes, speech and voice changes are also common with Parkinson’s disease. Advanced patients will often experience slurred speech, while early-stage sufferers may experience less dramatic voice changes. Some speak more quietly or in low tones, others have a hoarse voice or little inflection, enunciation is usually still crystal clear. Another phenomenon associated with Parkinson’s disease is known as masking, and involves natural facial expressions and gross motor skills. More specifically, sufferers may struggle to move and control small muscles in the face, which can result in a blank stare or a serious expression during a lighthearted conversation, plus infrequent blinking.
Two symptoms caused by the impairment of the neurons that control movement are bradykinesia and rigidity, or slowed movement and stiffness of the limbs, respectively. While both of these are very normal developments in healthy individuals above the age of 60, the difference with Parkinson’s disease is that the slowness and stiffness doesn’t go away throughout the day. Posture and balance may also be impaired, leading to a stooped posture and possible back injuries. Leaning and slouching are both signs of a stooped posture as well as early indicators of Parkinson’s disease.
In addition to movement-related symptoms, Parkinson’s disease may also produce non-motor symptoms, or ones which are unrelated to movement. These include apathy, depression, constipation, sleep behavior disorders, anosmia, and cognitive impairment. Apathy refers to a lack of interest or enthusiasm, depression is a mood disorder characterized by feelings of anger and sadness, and constipation is a digestive problem involving dry bowel movements. Sleep behavior disorders refer to parasomnias with undesirable arousals from sleep, anosmia means the partial or complete loss of sense of smell, and cognitive impairment can involve memory and concentration problems, which can range from mild to severe. Oftentimes, sufferers of Parkinson’s disease say they are more affected by these non-motor symptoms than they are by motor symptoms.
https://www.parkinson.org/understanding-parkinsons/10-early-warning-signs
https://www.healthline.com/health/parkinsons-warning-signs
https://www.mayoclinic.org/diseases-conditions/parkinsons-disease/symptoms-causes/syc-20376055