Movement changes
The ongoing loss of dopamine causes movement to become progressively slower and smaller. When the PD medications are working, movement can still be performed even if slowly but when the medications wear off, the person is often unable to move without the assistance of a walking aid or another person.
Walking
Walking becomes slower with shuffling and foot drag, there can be little or no arm swing when walking, stepping may become faster and smaller (festination) and stepping may stop involuntarily, called ‘freezing of gait’. All of these changes can all increase the risk of falling. As PD progresses, PD medications can become less effective at controlling these changes.
Freezing of gait typically presents in the mid to late stages of PD, worsening over time.
There are many triggers to freezing of gait including:
- starting to walk
- approaching or walking through doorways
- performing another task when walking, such as talking
- turning
- sudden distractions, such as dog barking, phone ringing
Balance and falls
Mild balance changes are commonly present from the time of diagnosis but generally don’t interfere with mobility and walking until the mid stages. The combination of walking and balance changes leads to a marked increase in the risk of falls when walking.
By the mid stages of PD over 60% of people with PD will experience a fall in a 12 month period.
Turning is a simple activity that all people perform numerous times a day, however, turning is one of the high falls risk movements in PD. Festination and freezing of gait are commonly triggered by turning thus increasing the risk of falls.
Tremor
Tremor is not present in everyone who has PD. Tremor due to PD usually presents only at rest and stops during voluntary movement. In the early stages of PD, tremor affects limbs on one side of the body, and is most noticeable in the hand or foot. Tremor can also develop in the lips, chin and jaw.
Tremor can cause embarrassment leading the person to withdraw from their social network. There can be other causes of tremor, such as the condition essential tremor or it can be a side effect of medications and stress. A neurologist specialised in movement disorders will be able to determine the cause of the tremor.
Speech and swallowing
As speech and swallowing are motor tasks, they usually worsen over time as more dopamine producing cells are lost in the brain.
Speech symptoms can vary between people with PD. A person with PD may have difficulty communicating because of the following changes:
- soft voice due to loss of volume
- monotone voice with loss of intonation
- slurring or mumbling of words
- fast speed of talking and stammering or ‘freezing’
- difficulty finding words causing speech to slow
- loss of facial expression.
Swallowing and eating difficulties, known as dysphagia, are thought to affect over 90% of all people with PD. Common swallowing problems include:
- struggling to chew and swallow tough food such as steak
- difficulty swallowing tablets which may feel ‘stuck’ in the throat or oesophagus
- coughing especially after having a drink and choking on solid foods such as nuts or toast.
Swallowing difficulties increase the risk of aspirating food or fluids into the lungs which may then lead to pneumonia.
The automatic swallowing of saliva can be disrupted in PD leading to drooling. Excessive flexed posture of the trunk and head can make drooling worse.
Some people may have the reverse and experience a dry mouth.
Drooling may cause social embarrassment as well as oral hygiene problems.
Stooped posture
Stooped posture can become exaggerated as PD progresses.
Weakness contributes to this excessive stooping however the decrease in dopamine results in the loss of the ‘automatic’ reminder to keep an upright posture. The less dopamine the worse the stooped posture. Posture can improve when the PD medications are working (‘on’ time) and worsen when they’re not (‘off’ time).
Excessive stooped posture can result in neck and back pain, difficulty eating and swallowing, disruption to speech and communication, increased difficulty with personal care such as shaving and dressing and difficulty maintaining balance.
Dystonia can also cause a flexed posture.
Dystonia
Dystonia is similar to muscles cramps but the muscle tightening is sustained causing joints to stiffen and often twist. Dystonia can be very painful.
Dystonia can be present in one part of the body, such as the arm, or several parts, such as the arm and leg usually on the same side, as well as face, neck and trunk. Dystonia in the feet can cause the toes to claw and the foot may turn inwards at the ankle.
Dystonia can be a symptom of PD or a side effect of PD medications.
It can present when the PD medications have worn off (‘off dystonia’) or when the effect of the medications is at its peak (‘on dystonia’).
Dystonia is more common in people who were young when they were diagnosed with PD.
Dyskinesias
These are involuntary random movements that are described by people as irregular jerking, wiggling or twitching movements.
Dyskinesia is thought to be a result of the long term use of PD medications, in particular levodopa, and also part of the normal progression of PD. Dyskinesia develops during the mid to advanced stages of PD.
Dyskinesia occurs when effect of PD medications are at their peak, and rarely when their effect is wearing off.
Excessive dyskinesia can make everyday tasks difficult to perform, such as dressing and eating. Dyskineia can disturb a person’s balance, cause excessive sweating and weight loss.
Non-Motor Symptoms
There are a range of non-motor symptoms that, like the motor symptoms, worsen as the loss of dopamine increases. Not everyone will go on to develop all of these non-motor symptoms.
Among the more common non-motor symptoms experienced as the PD progresses are:
- cognitive changes, such as difficulty concentrating when reading or conversing, poor memory, difficulty planning tasks, difficulty following instructions and even dementia in the very advanced stages.
- fatigue that limits everyday activities
- mood changes such as depression, anxiety and apathy
- hallucinations and psychosis
- difficult to control low blood pressure causing dizziness or fainting
- difficulty with bowels such constipation and incontinence
- difficulty with bladder such as urgency, frequency and incontinence
- pain
- weight loss
- worsening sleep disorder, such as insomnia, excessive day time sleepiness, vivid distressing dreams
