Symptoms of Parkinson's disease
Parkinson's disease (PD) is characterised by 4 major symptoms — tremor, rigidity, bradykinesia (slowness of movement) and postural instability — but also has a variety of irritating and disruptive symptoms that can be just as important. The following is an explanation of the more common symptoms.
Tremor
Undoubtedly the most noticeable aspect of PD is a 'resting tremor', one that is apparent when the limb is relaxed and not in use. Normally the tremor is obvious first in an upper limb, usually in the wrist and fingers, as it is the arms that can be relaxed easily (e.g. resting on the arm of a chair). Tremor in the lower limbs is less obvious as it is very difficult for the lower half of the body to be completely at rest even when seated. However, after a few minutes of sitting, the tremor can become apparent by a tapping of the toes or heel on the floor.
Resting tremor is a regular, rhythmic relaxation and contraction of muscles that is most evident when active movement has ceased. People will find there is a few seconds' delay between assuming a relaxed posture and the beginning of the tremor and that the tremor reduces when active movement begins again. The tremor is not evident when the person is asleep.
Although resting tremor is typical of PD, in a few cases a faster tremor may be brought on by active movement. This form of tremor is most evident when the person begins any form of activity. For example, when the person begins to walk, the hands begin to shake, and this can be more disabling than a resting tremor. The pathology giving rise to PD is not completely clear, and hence there is a possibility that the unusual features of this kind of tremor are due to the involvement of sites in the brain other than those that produce the more classical resting tremor.
Emotional stress has been noted to increase the tremor; this is possibly due to the increase of adrenaline in the system thus creating a further imbalance in the brain.
Tremor is successfully treated by medication in most cases; the role of surgery in the treatment of tremor is currently being evaluated.
Rigidity
This refers to the resistance felt in a person's joints and muscles when they are passively moved. When this resistance is consistent it is known as 'lead pipe rigidity'. More common is the jerky, stiff and variable quality known as 'cog-wheel rigidity'. This form of rigidity usually appears in the upper arms and may cause a painful stiffness on walking. Increasing intensity of rigidity may be a cause of sleep disturbance.
Rigidity is the reason for the common complaint of 'freezing'. The person feels that some muscles are so rigid they will not move; this usually occurs at the point of commencement of movement, such as trying to stand up or walk.
Bradykinesia
Bradykinesia is the term used for slowness in initiating and executing movement, and difficulty in performing repetitive movements. This is the most disabling symptom. Voluntary movements are difficult to initiate and are then slow and difficult to sustain on repetition, with involvement of smaller degrees of muscle recruitment than normal.
People also exhibit problems in selecting and organising motor programmes e.g. in performing 2 movements at once or carrying out sequences of motor tasks.
The brain is unable to maintain control over the smooth co-ordination of involuntary movements, so that fine gestures and associated movements such as arm swinging can be lost. It is this factor that is behind the infrequent blinking and the lack of facial expression typical of PD and known as 'masking'.
Bradykinesia can also lead to difficulties in swallowing and speech. PD people have more difficulty in motor actions that are internally generated, whereas their performance improves when the same movements have to be driven in externally triggered mode or when they rely on external cues.
Postural changes
A flexed posture may develop, along with a slowing of postural and righting (balancing) reflexes, leading to gait disorders and a propensity to fall. Shuffling, acceleration of walking or retropulsion can result in falls.
Freezing
As the disease progresses, many people will experience freezing when initiating movements, turning and going through doorways. They also experience difficulty with ending movements. This is most common in walking but may occur during any movement. Freezing does not readily respond to levodopa, but apomorphine may be used with short-term benefit.
Gait disturbance
The gait disturbance of PD was first described in detail by Sir James Parkinson when he noted the transfer of weight such that 'the patient falls into a running pace' (known as festinating gait). The person will find that steps are shorter and there is a tendency to break into a little run and totter forward. This is due to a shifting forward of the centre of gravity with the tendency to bend the head forward and to hunch the shoulders (a flexed posture). Also typical of the disturbed pattern of walking is the toe being put to the ground first instead of the heel, causing the person to shuffle.
Restless legs
This is a symptom that is associated with the fact that the tremor affecting people with PD is more commonly a resting one. People find they have periods of being unable to sit still, particularly in the evening. There is a sense of restlessness and the person needs to walk around to relieve the discomfort caused by this constant movement.
Cramps
Reported as a night-time symptom, cramps may respond to quinine, or a change in medication or be relieved by stretching and exercise. Some dystonias (cramps) may be an early sign of PD or related to peak blood levels of medication or a sign that medication is due.
Micrographia
This refers to the loss of writing skill as the fine movements associated with finger and wrist control are diminished. The handwriting starts off normally rounded and well formed but then diminishes in size and clarity until words and then letters become indecipherable.
Lethargy
People with PD may also suffer from fatigue that is not relieved by resting. While this may be a part of the disease, every effort must be made to combat the lethargy that may take hold of the person and reduce them to inactivity. This inactivity may increase the tremor and other symptoms and aggravate movement problems.
Bowel and bladder problems
Constipation can be a severe problem and may be aggravated by anticholinergic drugs that are used to treat PD symptoms. The fine movements necessary for bladder control can also be affected, making urine retention a common problem. This can reduce the desire for fluids, making constipation worse. Apomorphine, used in PD for periods of severe akinesia (i.e. limited movement or severe freezing), has also been shown to cause an urgency to empty the bladder.
Intellectual impairment
Drug treatment may produce confusion and changes in mood. Intellectual impairment is not normally a feature of PD, although recent studies indicate that some impairment in sequencing and rigidity of thinking may be present. The development of any intellectual difficulties needs thorough assessment and should not be assumed to be related to PD.
Depression
Depression is a very common problem. It may be difficult to distinguish between the symptoms of PD and depression (e.g. lethargy, insomnia and loss of appetite). Causes of depression may be reactive (a normal reaction to the diagnosis of a chronic illness or increasing loss of abilities). It may be relieved by treatment of symptoms (by antidepressants), support from others and support groups. Endogenous depression is thought to be a part of the disease process.
Disturbed sleep
Disturbed sleep is also a common problem for many people with PD and can be related to either the disease itself or to the medication. It may be relieved by antidepressants and hypnotics [drugs that help induce sleep], but disturbances may be caused by pain, urinary difficulties, stiffness, cramps and problems with moving in bed. Some night-time discomfort may improve with slow release medication. The sleep-wake cycle may also have altered and need attention.
Sensory disturbances
Sensory disturbances are reported in up to 40 per cent of people with PD. The most common are numbness, tingling, pain and coldness. Loss of smell is often a very early symptom. All these symptoms may fluctuate later in the disease.
Visual disturbances, such as poor contrast sensitivity, have been recorded and this could cause difficulties, experienced by many people with PD, in moving from one floor surface to another.
Other symptoms may be seborrhoea (a waxy skin), weight loss of up to 10 per cent (more significant in females) and shallow breathing.
Last Reviewed: 24 July 2002
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