alt=Black and white picture of a male with<unk>  stooping forward as he walks. He is viewed from the left side with a chair behind him. alt=French signature reads "Catherine Metzger 13 Octobre 1869" The most recognizable early symptoms are movement ("motor") related. Non-motor symptoms, including autonomic dysfunction (dysautonomia), neuropsychiatric problems (mood, cognition, behavior or thought alterations), and sensory (especially altered sense of smell) and sleep difficulties, are usually associated with later stages, but may present at the time of diagnosis. Motor Four motor symptoms are considered as cardinal signs in<unk> : tremor, slowness of movement (bradykinesia), rigidity, and postural instability. The most common presenting sign is a coarse, slow tremor of the hand at rest, which disappears during voluntary movement of the affected arm and in the deeper stages of sleep. It typically appears in only one hand, eventually affecting both hands as the<unk>  progresses. Frequency of<unk>  tremor is between 4 and 6 hertz (cycles per second). A feature of tremor is "pill-rolling", the tendency of the index finger and thumb to touch and perform together with a circular movement. The term derives from the similarity between the movement of people with<unk>  and the early pharmaceutical technique of manually making pills. Bradykinesia is found in every case of<unk> , and is due to disturbances in motor planning of movement initiation, and associated with difficulties along the whole course of the movement process, from planning to initiation to execution of a movement. Performance of sequential and simultaneous movement is impaired. Bradykinesia is the most handicapping symptom of<unk> , leading to difficulties with everyday tasks such as dressing, feeding, and bathing. It leads to particular difficulty in carrying out two independent motor activities at the same time, and can be made worse by emotional stress or concurrent illnesses. Paradoxically, people with<unk>  can often ride a bicycle or climb stairs more easily than walk on the level. While most physicians may readily notice bradykinesia, formal assessment requires persons to do repetitive movements with their fingers and feet. 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, known as 'lead-pipe rigidity', or ratchet-y, known as '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<unk> . In early stages of<unk> , rigidity is often asymmetrical and tends to affect the neck and shoulder muscles prior to the muscles of the face and extremities. With the progression of the<unk> , rigidity typically affects the whole body and reduces the ability to move. Postural instability is typical in the later stages of the<unk> , leading to impaired balance and frequent falls, and secondarily to bone fractures, loss of confidence, and reduced mobility. Instability is often absent in the initial stages, especially in younger people, especially prior to the development of bilateral symptoms. Up to 40% of people diagnosed with<unk>  may experience falls, and around 10% may have falls weekly, with the number of falls being related to the severity of<unk> . Other recognized motor signs and symptoms include gait and posture disturbances such as festination (rapid shuffling steps and a forward-flexed posture when walking with no flexed arm swing). Other common signs include freezing of gait (brief arrests when the feet seem to get stuck to the floor, especially on turning or changing direction), a slurred, monotonous, quiet voice, mask-like facial expression, and handwriting that gets smaller and smaller. Neuropsychiatric<unk>  causes neuropsychiatric disturbances ranging from mild to severe. They include disorders of cognition, mood, behavior, and thought. Cognitive disturbances can occur in the early stages or sometimes prior to diagnosis, and increase in prevalence with duration of the<unk> . The most common cognitive deficit is executive dysfunction, which can include problems with planning, cognitive flexibility, abstract thinking, rule acquisition, inhibiting inappropriate actions, initiating appropriate actions, working memory, and control of attention. Other cognitive difficulties include slowed cognitive processing speed, impaired recall, and impaired perception and estimation of time. Nevertheless, improvement appears when recall is aided by cues. Visuospatial difficulties are also part of the<unk> , 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<unk>  has two to six times the risk of dementia compared to the general population. Up to 78% of people with<unk>  have<unk>  dementia. The prevalence of dementia increases with age, and to a lesser degree, duration of the<unk> . Dementia is associated with a reduced quality of life in people with<unk>  and their caregivers, increased mortality, and a higher probability of needing nursing home care. Impulse-control disorders, including pathological gambling, compulsive sexual behavior, binge eating, compulsive shopping, and reckless generosity, can be caused by medication, particularly orally active dopamine agonists. The dopamine dysregulation syndrome – with wanting of medication leading to overuse – is a rare complication of levodopa use. Punding, in which complicated, repetitive, aimless, stereotyped behaviors occur for many hours, is another disturbance caused by anti-Parkinson medication. Psychosis Psychosis can be considered a symptom with a prevalence at its widest range from 26 to 83%. Hallucinations or delusions occur in about 50% of people with<unk>  over the course of the illness, and may herald the emergence of dementia. These range from minor hallucinations – "sense of passage" (something quickly passing beside the person) or "sense of presence" (the perception of something/someone standing just to the side or behind the person) – to full blown vivid, formed visual hallucinations and paranoid ideation. Auditory hallucinations are uncommon in<unk> , and are rarely described as voices. Psychosis is now believed to be an integral part of the<unk> . A psychosis with delusions and associated delirium is a recognized complication of anti-Parkinson drug treatment and may also be caused by urinary-tract infections (as frequently occurs in the fragile elderly), but drugs and infection are not the only factors, and underlying brain pathology or changes in neurotransmitters or their receptors (e.g., acetylcholine, serotonin) are also thought to play a role in psychosis in<unk> . Behavior and mood Behavior and mood alterations are more common in<unk>  without cognitive impairment than in the general population, and are usually present in<unk>  with dementia. The most frequent mood difficulties are depression, apathy, and anxiety. Depression has been estimated to appear in 20 to 35% of people with<unk> , and can appear at any stage of the<unk> . It can manifest with symptoms that are common to the<unk>  process (fatigue, insomnia, and difficulty with concentration), which makes diagnosis difficult. The imbalance and changes in dopamine, serotonin, and noradrenergic hormones are known to be a primary cause of depression in<unk> -affected people. Another cause is the functional impairment that is caused by the<unk> . Symptoms of depression can include loss of interest, sadness, guilt, feelings of helplessness/hopelessness/guilt, and suicidal ideation. Suicidal ideation in<unk> -affected people is higher than in the general population, but suicidal attempts themselves are lower than in people with depression without<unk> . Risk factors for depression in<unk>  can include<unk>  onset under age 50, being a woman, previous history of depression, severe motor symptoms, and others. Anxiety has been estimated to have a prevalence in<unk> -affected people usually around 30–40% (60% has been found). Anxiety can often be found during "off" periods (times when medication is not working as well as it did before) with<unk> -affected people suffering from panic attacks more frequently compared to the general population. Both anxiety and depression have been found to be associated with decreased quality of life. Symptoms can range from mild and episodic to chronic with potential causes being abnormal gamma-aminobutyric acid levels and embarrassment or fear about symptoms or<unk> . Risk factors for anxiety in<unk>  are<unk>  onset under age 50, women, and "off" periods. Apathy and anhedonia can be defined as a loss of motivation and an impaired ability to experience pleasure, respectively. They are symptoms classically associated with depression, but they differ in<unk> -affected people in treatment and mechanism, and do not always occur with depression. Apathy presents in around 16.5–40%. Symptoms of apathy include reduced initiative/interests in new activities or the world around them, emotional indifference, and loss of affection or concern for others. Apathy is associated with deficits in cognitive functions including executive and verbal memory. Other Sleep disorders are a feature of the<unk>  and can be worsened by medications. Symptoms can manifest as daytime drowsiness (including sudden sleep attacks resembling narcolepsy), disturbances in Rapid eye movement sleep, or insomnia. REM behavior disorder, in which people act out dreams, sometimes injuring themselves or their bed partner, may begin many years before the development of motor or cognitive features of<unk>  or dementia with Lewy bodies. Alterations in the autonomic nervous system can lead to orthostatic hypotension (low blood
Parkinson's disease
Dementia with Lewy bodies
Parkinsonism
Antipsychotic
Parkinson-plus syndrome
Essential tremor
Alzheimer's disease
Progressive supranuclear palsy