Introduction to Parkinson's Disease

Early Presentation of Parkinson's Disease

Early presentation of Parkinson's disease is often missed because the signs can be very subtle and the progression of disease is typically slow. A patient may complain of generally not feeling well, or feeling a little down, or just a little shaky. Usually, it is friends or family who first notice that something may be wrong and they will encourage the patient to be checked by a doctor.

There are four primary symptoms of Parkinson's disease, known as TRAP:

• Tremor
• Rigidity
• Akinesia
• Postural Instability

Tremor

Most patients present with a tremor on one side (unilateral or asymmetric) which is more noticeable at rest. Most often the tremor is noticeable in one hand which exhibits the typical "pill-rolling" movement of the thumb and opposing fingers. A resting tremor is present in 70-80% of people diagnosed with Parkinson's disease and disappears with action of the hand. It is also frequently noticeable when the patient is walking. Tremor is often the primary symptom which spurs a patient to seek medical help since, depending on its severity, it is one of the first symptoms that can begin to interfere with daily living. Severity varies among patients but the tremor almost always worsens with fatigue, stress, and cold weather. A tremor can also occur in the tongue, lower jaw, or legs. Some patients report a feeling of internal shaking which is not visible to others. Tremors usually disappear during sleep. In older adults, tremors are less common.

Rigidity

Rigidity consists of increased tone or stiffness of the muscles. Most patients with early Parkinson's disease do not report the feeling of rigidity but may report feelings of vague aching or discomfort in a limb. However, when the physician manipulates the limb during the physical examination, signs of rigidity become evident. There is resistance to passive movement which may be seen at any point in testing the full range of motion in the affected limb. If a tremor exists in the rigid limb, one may see smooth movement replaced with a broken up ratchet type of action ("cogwheel rigidity"). When rigidity occurs in the face, it can cause the classic "mask-like" appearance associated with Parkinson's disease. Rigidity can occur in any limb, the neck, or facial musculature. Some patients report pain due to the rigidity of arms and shoulders. Rigidity is not a part of the normal aging process so if a person presents to a doctor with rigidity and improves with anti-parkinsonian drugs, it is most likely caused by Parkinson's disease.

Akinesia and Bradykinesia

Akinesia refers to a significant reduction or absence of spontaneous movement and bradykinesia refers to slowness of movement. Bradykinesia occurs more frequently and is usually reported to be the most distressing and troubling symptom as it makes the simplest of tasks very time consuming. It is manifested in a delay of movement initiation (e.g., taking the first step in walking) and slow response once the action begins (e.g., walking very slowly). Bradykinesia interferes with many daily activities such as walking, dressing, household chores, and getting up from or sitting down in a chair. Especially frustrating is that bradykinesia is unpredictable and can occur in the middle of an activity. Two of the most common aspects of bradykinesia related to Parkinson's disease is that it is usually asymmetric (in up to 75% of patients) and that fatigue sets in with continued activity. This can be seen when a patient is asked to tap the thumb and index finger together rapidly. Typically, the rate of tapping progressively slows down.

Bradykinesia tends to affect fine motor movement more than gross motor movement, as well as repetitive movement. Thus, the patient notices difficulty in activities that require dexterity such as fastening buttons, or in tasks requiring repetitive hand motions such as brushing teeth.

In the face, bradykinesia may manifest itself as a decrease in facial expression and/or eye blinking. Some patients experience slowness in the muscles involved in swallowing, leading to a buildup of saliva which could cause choking.

Postural Instability

Postural instability is a general term that involves gait changes and an impaired sense of balance. It is noticeable when the patient with Parkinson's disease moves or turns abruptly which may cause them to lose their balance and fall. Gait changes include asymmetric slowness, shuffling, and reduced arm swinging. Some patients lean forward or backward also causing them to fall easily especially if they are bumped. For some patients, especially older adults, postural instability may be a later presenting symptom of Parkinson's disease.