What is Parkinson's Disease?
Parkinson's disease (PD) is a degenerative disorder of the central nervous system mainly
affecting the motor system. Early in the course of the disease, the most obvious symptoms
are movement-related; these include shaking, rigidity, slowness of movement and difficulty
with walking and gait. Later, thinking and behavioural problems may arise, with dementia
commonly occurring in the advanced stages of the disease, and depression being the most
common psychiatric symptom. Other symptoms include sensory, sleep, and emotional problems.
The main motor symptoms are collectively called "parkinsonism", or a "parkinsonian syndrome".
The disease can be either primary or secondary. Primary Parkinson's disease has no known
cause, although some atypical cases have a genetic origin. Secondary parkinsonism is due to
known causes like toxins. Many risks and protective factors have been investigated: the clearest
evidence is for an increased risk in people exposed to certain pesticides and a reduced risk in
tobacco smokers. The motor symptoms of the disease result from the death of cells in the
substantia nigra, a region of the midbrain. This results in not enough dopamine in these areas.
The reason for this cell death are poorly understood but involves the build-up of proteins into
Lewy bodies in the neurons. Where the Lewy bodies are located is partly related to the expression
and degree of the symptoms. Diagnosis of typical cases is mainly based on symptoms, with tests such as neuroimaging being used for confirmation.
Treatments, typically the anti-parkinson medications L-DOPA and dopamine agonists, improve the
early symptoms of the disease. As the disease progresses and neurons continue to be lost, these
medications become ineffective while at the same time produce a complication marked by
involuntary writhing movements. Diet and some forms of rehabilitation have shown some
effectiveness at improving symptoms. Surgery to place deep brain stimulation have been used
to reduce motor symptoms in severe cases where drugs are ineffective. Research directions
include investigations into new animal models of the disease and of the potential usefulness of
gene therapy, stem cell transplants, and neuroprotective agents. Medications to treat
non-movement-related symptoms of PD, such as sleep disturbances and emotional problems,
The term parkinsonism is used for a motor syndrome whose main symptoms are tremor at rest,
stiffness, slowing of movement and postural instability. Parkinsonian syndromes can be divided
into four subtypes, according to their origin:
primary or idiopathic
secondary or acquired
Parkinson plus syndromes or multiple system degeneration.
Parkinson's disease is the most common form of parkinsonism and is usually defined as "primary" parkinsonism, meaning parkinsonism with no external identifiable cause. In recent years several genes that are directly related to some cases of Parkinson's disease have been discovered. As much as this conflicts with the definition of Parkinson's disease as an idiopathic illness, genetic parkinsonism disorders with a similar clinical course to PD are generally included under the Parkinson's disease label. The terms "familial Parkinson's disease" and "sporadic Parkinson's disease" can be used to differentiate genetic from truly idiopathic forms of the disease.
Usually classified as a movement disorder, PD also gives rise to several non-motor types of symptoms such as sensory deficits, cognitive difficulties, and sleep problems. Parkinson plus diseases are primary parkinsonisms which present additional features. They include multiple system atrophy, progressive supranuclear palsy, corticobasal degeneration, and dementia with Lewy bodies.
In terms of pathophysiology, PD is considered a synucleiopathy due to an abnormal accumulation of alpha-synuclein protein in the brain in the form of Lewy bodies, as opposed to other diseases such as Alzheimer's disease where the brain accumulates tau protein in the form of neurofibrillary tangles. Nevertheless, there is clinical and pathological overlap between tauopathies and synucleinopathies. The most typical symptom of Alzheimer's disease, dementia, occurs in advanced stages of PD, while it is common to find neurofibrillary tangles in brains affected by PD.
Dementia with Lewy bodies (DLB) is another synucleinopathy that has similarities with PD, and especially with the subset of PD cases with dementia. However, the relationship between PD and DLB is complex and still has to be clarified. They may represent parts of a continuum or they may be separate diseases.
Signs and symptoms
Parkinson's disease affects movement, producing motor symptoms. Non-motor symptoms, which include autonomic dysfunction, neuropsychiatric problems (mood, cognition, behaviour or thought alterations), and sensory and sleep difficulties, are also common. Some of these non-motor symptoms are often present at the time of diagnosis and can precede motor symptoms.
Further information: Parkinsonian gait
Four motor symptoms are considered cardinal in PD:
slowness of movement
Tremor is the most apparent and well-known symptom. It is the most common; though around 30% of individuals with PD do not have tremor at disease onset, most develop it as the disease progresses. It is usually a rest tremor: maximal when the limb is at rest and disappearing with voluntary movement and sleep. It affects to a greater extent the most distal part of the limb and at onset typically appears in only a single arm or leg, becoming bilateral later. Frequency of PD tremor is between 4 and 6 hertz (cycles per second). A feature of tremor is pill-rolling, the tendency of the index finger of the hand to get into contact with the thumb and perform together a circular movement. The term derives from the similarity between the movement in people with PD and the earlier pharmaceutical technique of manually making pills.
Hypokinesia (slowness of movement) is another characteristic feature of PD, and is associated with difficulties along the whole course of the movement process, from planning to initiation and finally execution of a movement. Performance of sequential and simultaneous movement is hindered. Bradykinesia is commonly a very disabling symptom in the early stages of the disease. Initial manifestations are problems when performing daily tasks which require fine motor control such as writing, sewing or getting dressed. Clinical evaluation is based in similar tasks such as alternating movements between both hands or both feet. Bradykinesia is not equal for all movements or times. It is modified by the activity or emotional state of the subject, to the point that some people are barely able to walk yet can still ride a bicycle. Generally people with PD have less difficulty when some sort of external cue is provided.
Rigidity is stiffness and resistance to limb movement caused by increased muscle tone, an excessive and continuous contraction of muscles. In parkinsonism the rigidity can be uniform (lead-pipe rigidity) or ratchety (cogwheel rigidity). The combination of tremor and increased tone is considered to be at the origin of cogwheel rigidity. Rigidity may be associated with joint pain; such pain being a frequent initial manifestation of the disease. In early stages of Parkinson's disease, rigidity is often asymmetrical and it tends to affect the neck and shoulder muscles prior to the muscles of the face and extremities. With the progression of the disease, rigidity typically affects the whole body and reduces the ability to move.
Postural instability is typical in the late stages of the disease, leading to impaired balance and frequent falls, and secondarily to bone fractures. Instability is often absent in the initial stages, especially in younger people. Up to 40% may experience falls and around 10% may have falls weekly, with number of falls being related to the severity of PD.
Other recognized motor signs and symptoms include gait and posture disturbances such as festination (rapid shuffling steps and a forward-flexed posture when walking), speech and swallowing disturbances including voice disorders, mask-like face expression or small handwriting, although the range of possible motor problems that can appear is large
Parkinson's disease can cause neuropsychiatric disturbances which can range from mild to severe. This includes disorders of speech, cognition, mood, behaviour, and thought
Cognitive disturbances can occur in the early stages of the disease and sometimes prior to diagnosis, and increase in prevalence with duration of the disease. The most common cognitive deficit in affected individuals is executive dysfunction, which can include problems with planning, cognitive flexibility, abstract thinking, rule acquisition, initiating appropriate actions and inhibiting inappropriate actions, and selecting relevant sensory information. Fluctuations in attention and slowed cognitive speed are among other cognitive difficulties. Memory is affected, specifically in recalling learned information. Nevertheless, improvement appears when recall is aided by cues. Visuospatial difficulties are also part of the disease, seen for example when the individual is asked to perform tests of facial recognition and perception of the orientation of drawn lines.
A person with PD has two to six times the risk of dementia compared to the general population. The prevalence of dementia increases with duration of the disease. Dementia is associated with a reduced quality of life in people with PD and their caregivers, increased mortality, and a higher probability of needing nursing homecare.
Behaviour and mood alterations are more common in PD without cognitive impairment than in the general population, and are usually present in PD with dementia. The most frequent mood difficulties are depression, apathy and anxiety. Establishing the diagnosis of depression is complicated by symptoms that often occur in Parkinson's including dementia, decreased facial expression, decreased movement, a state of indifference, and quiet speech. Impulse control behaviours such as medication overuse and craving, binge eating, hypersexuality, or pathological gambling can appear in PD and have been related to the medications used to manage the disease. Psychotic symptoms—hallucinations or delusions—occur in 4% of people with PD, and it is assumed that the main precipitant of psychotic phenomena in Parkinson’s disease is dopaminergic excess secondary to treatment; it therefore becomes more common with increasing age and levodopa intake.
In addition to cognitive and motor symptoms, PD can impair other body functions.
Sleep problems are a feature of the disease and can be worsened by medications. Symptoms can manifest as daytime drowsiness, disturbances in REM sleep, or insomnia. A systematic review shows that sleep attacks occur in 13.0% of patients with Parkinson's disease on dopaminergic medications.
Alterations in the autonomic nervous system can lead to orthostatic hypotension (low blood pressure upon standing), oily skin and excessive sweating, urinary incontinence and altered sexual function. Constipation and gastric dysmotility can be severe enough to cause discomfort and even endanger health. PD is related to several eye and vision abnormalities such as decreased blink rate, dry eyes, deficient ocular pursuit (eye tracking) and saccadic movements (fast automatic movements of both eyes in the same direction), difficulties in directing gaze upward, and blurred or double vision. Changes in perception may include an impaired sense of smell, sensation of pain and paresthesia (skin tingling and numbness). All of these symptoms can occur years before diagnosis of the disease.
Our support and care
George Springall Homecare provides dedicated and experienced staff to help you maintain your quality of life and support you and your family through the difficult times. We create a specialized care plan that focuses on meeting all your needs. We support you set up realistic goals you wish to achieve and we are there to help when ever you need through out your journey to achieving your goals.
This might include:
helping with personal care and getting you ready for the day or for a good night sleep
catheter care and continence management to maintain your dignity and comfort
prompting or administering your medication to manage your symptoms
assisting with nutrition and hydration to keep you healthy
assisting with routine household chores and shopping so your home life is as you would like it to be
emotional or social support to keep you connected to the people who are important to you
support with rehabilitation to get back to a normal life and independence
Further information and support is available from Parkinson's UK
Contact us to discuss a care package and support service for you.