Overview: Movement Disorders
Movement disorders involve either abnormal decrease in movement or increase in movement. Parkinson disease is a common disorder with decreased movement (hypokinetic), and Essential tremor is the most common disorder with excessive movement (hyperkinetic).
The term “parkinsonism” refers to the constellation of symptoms associated with decreased effect of dopamine in the brain, which results in slow movement, resting tremor, stiffness, postural instability, and slowed walking. These symptoms can be from various causes including exposure to medications, toxins, Parkinson disease, or “Parkinson-plus syndromes.”
Some antipsychotic and anti-nausea medications can cause medication induced parkinsonism. There are neuro-toxins that can rarely cause parkinsonism.
When there is no other clear cause and a person develops signs of parkinsonism that progress, Parkinson disease (PD) is diagnosed. When compared to other causes of parkinsonism, PD tends to have more asymmetry in presentation (one side of the body is more affected than the other) and tends to have a better response to medical treatments.
It is not well understood what causes PD, but this is an area of current research.
PD is a clinical diagnosis, meaning that there is no specific blood test or MRI to state whether or not a person has PD. A Neurologist will be able to do a details evaluation and rule out other causes of symptoms, so as to allow an early diagnosis of PD, which can lead to beneficial treatment and improvement in quality of life.
Parkinson disease has prominent motor symptoms, but there are also less well publicized but important non-motor symptoms to note.
Motor symptoms in PD
- Bradykinesia must be present to diagnose PD. This means that the movement of an area of the body is slower than would be expected. The degree of slowing may worsen as the movement continues and there may be hesitations in the movements.
- Rigidity or stiffness to the body. This is sometimes called “cog-wheeling,” reflecting the sensation of cogs “catching” as a joint is passively moved, or “lead pipe rigidity,” reflecting a constant stiffness
- Resting tremor. When an extremity or part of the body is at rest, it oscillates or tremors. Typically, this tremor improves when starting intentional movement. The classic resting tremor is a “pill rolling” tremor of the hand at a rate of 4 to 6 Hz. Often this is asymmetric.
- Postural instability reflects the nervous systems difficulty in maintaining a posture, resulting in imbalance and falls. This often presents later in the course of PD. This can result in a shuffling gait. Other terms used in this category include retropulsion (a person with PD may start to fall backwards upon first standing) and festination (a person with PD starts to walk and begins to lean more and more forward until momentum causes uncontrolled acceleration).
- Hypomimia is a flat or masked facial expression. A person may lose the typical facial expressions once noted.
- Difficulty swallowing
- Decreased blinking
- Stooped posture
- Freezing of movements
Non-Motor symptoms in PD
- Orthostatic hypotension, which is a drop in blood pressure upon standing
- Sleep disorders
- Loss of smell
- Memory loss (later in the disease process)
- Psychosis / hallucinations (later in the disease process)
- Skin abnormalities, such as seborrheic dermatitis due to oily and flaky skin
There are a wide variety of medications when can be used to help with the symptoms of PD, particularly offering relief of the motor symptoms. Current medications available do not change the disease process or “cure” the PD, but instead help manage symptoms, which has been shown to improve quality of life and increase length of survival. The medications have varying side effect profiles and efficacy, so the Neurologist takes care to consider and discuss the options in detail.
Commonly used medications are discussed below:
Levodopa (such as in Sinemet)
- Levodopa is the most effective medication for treating parkinsonism. It is a pill that is converted to dopamine in the brain. Many formulations of levodopa also contain carbidopa (such as Sinemet), which lowers the total dose of levodopa needed and therefore can decrease the amount of gastrointestinal side effects. There are short-acting and long-acting formulations available. More recently, for people who have dysphagia and cannot safely swallow pills due to PD, there is an option called Duopa where a pump can give an infusion of levodopa through a stomach tube.
- Because levodopa is so reliably effective, a trial of this medication may be part of the diagnosis of PD
- Some patients experience a “wearing off” phenomenon where the benefit goes away at the end of the dose cycle. This can be addressed by changing the dosing frequency.
- It is possible to get dyskinesias, which can be painful stiffening or movement of muscles, due to excessive levodopa. This may result in a decrease in dosing.
- COMT inhibitors such as Contain can be used to further increase the availability and duration of levodopa in the body, if needed.
MAO-B (selegiline, rasagiline)
- Selective inhibitors of MAO-B, which is an enzyme that leads to breakdown of dopamine, can be used to increase the availability of dopamine in the brain. These may be used early in the PD disease process.
- Amantadine is a medication that blocks NMDA receptors and increases dopamine availability in the brain, helping with the tremor of PD and levodopa-induced dyskinesias. This may be used in mild to moderate PD, especially in younger people. In older patients, amantadine can cause disorientation or hallucinations.
Dopamine agonists (Mirapex, Requip, Neupro)
- Dopamine receptor agonists directly activate the dopamine receptors in the brain, therefore helping with symptoms. There are pill and transdermal patch options. In comparison to levodopa, dopamine agonists are somewhat less effective at treating PD symptoms and have a higher risk of dyskinesias. These medications have been associated with difficulty with impulse control, such as increased gambling or risky behavior, and therefore a person’s behavior should be monitored closely.
In addition to medication therapies, there are now exciting surgical options available that can greatly improve parkinsonian symptoms in PD.
Deep brain stimulation (DBS)
- DBS involves surgically implanting stimulators into regions of the brain associated with PD – such as pallidal DBS, thalamic DBS, or subthalamic nucleus (STN) DBS. The DBS stimulator can be adjusted and tailored for symptom control. DBS is approximately as beneficial as levodopa, however it has the benefit of much less motor fluctuations and no dyskinesias.
Parkinson Plus syndromes
There are other neurodegenerative conditions which involve parkinsonism but are distinct from PD due to the presence of other characteristics. It is important for the Neurologist to differentiate these conditions, as they are treated differently and have a different disease course.
Multiple System Atrophy (MSA)
- In addition to the parkinsonism, Multiple System Atrophy features autonomic nervous system failure and / or cerebellar dysfunction.
- The parkinsonism in MSA tends to be more mild and not involve a tremor, when compared to PD
- MSA has also been known as “Shy-Drager syndrome”
- The autonomic nervous system is the involuntary portion of a person’s nervous system that controls the internal organs, such as the heart, blood vessels, and the bladder. Due to this being affected, MSA often leads to severe orthostatic hypotension (a drop in blood pressure upon standing, which can result in a person passing out) and urinary incontinence, amongst other symptoms.
- The cerebellum in the portion of the central nervous that is responsible for coordinating voluntary movements. Due to this being affected, MSA can lead to abnormal posture, incoordination, abnormal speech, and falls.
- MRI of the brain can reveal a characteristic findings in the pons, called the “hot cross bun sign”
- Levodopa may provide some mild improvement in the parkinsonism very early in the course of MSA, but it can cause more levodopa-induced dyskinesias and typically becomes ineffective.
- As orthostatic hypotension is often the most disabling symptom in MSA, the treatments for MSA largely focus on this. Typically this begins with ensuring adequate hydration and using compression leg stockings to help blood flow return to the heart from the legs. If needed, medications such as midodrine, fludrocortisone, pyridostigmine, or droxidopa can be considered.
- A multidisciplinary team may include a Urologist, Speech Therapy, and Physical Therapy – so as to address urinary incontinence, dysphagia, and gait difficulties.
Progressive Supranuclear Palsy (PSP)
- Beyond parkinsonism, Progressive Supranuclear Palsy features impaired vertical eye movements, prominent neck rigidity, dystonia of the face, apathy, and often pseudobulbar affect (crying or laughing spells out of context).
- Of the parkinsonism symptoms, the postural instability and falls are most prominent in PSP.
- MRI of the brain can reveal a characteristic finding called the “hummingbird sign”
- PSP does not respond to levodopa. In fact, when differentiating the conditions, the Neurologist may prescribe levodopa. If there is a positive response, it may suggest PD. If there is no response, this would suggest PSP.
- Botox injections can help with dystonias
- Symptomatic management often includes involving Speech Therapy and Physical therapy.
Dementia with Lewy Bodies (DLB)
- In addition to parkinsonism, Dementia with Lewy Bodies involves early memory loss and significant psychiatric symptoms.
- DLB tends to have more subtle parkinsonism. In contrast to PD, the memory loss or cognitive impairment is prominent early in the disease course. While people with advanced PD can develop memory loss, it is only late in that disease course.
- The cognitive impairment in DLB can wax and wane, in contrast to Alzheimer dementia which is usually relatively steady and progressive.
- The psychiatric symptoms of DLB include troubling visual hallucinations or significant agitation.
- Levodopa can actually worsen the symptoms in DLB, especially the hallucinations
- Patients with DLB tend to be very sensitive to antipsychotic medications. Only very small doses should be used, if needed.
- Cholinesterase inhibitor medications such as rivastigmine may be used, as these have shown some benefit in helping both the cognitive impairment and psychosis in DLB
Corticobasal Degeneration (CBD)
- In Corticobasal Degeneration, the symptoms begin very similarly to Parkinson Disease, but then there is the development of prominent atypical symptoms such as limb apraxia (a person no longer knows how to use an extremity to do things that the person previously could do), alien limb phenomenon (an extremity may do activities on its own without intention of the person), myoclonus, and an action tremor.
- Impaired eye movements and cognitive impairment can also be seen, occasionally making it difficult to differentiate CBD clinically from PSP or DLB
- MRI of the brain may reveal asymmetric atrophy – or shrinkage – of the frontoparietal lobes.
- There is no direct treatment for CBD, but therapies can help with quality of life and safety.
Hyperkinetic movement disorders
In contrast to parkinsonism, hyperkinetic movement disorders involve an excessive amount of movement, or “extra” movement.
Essential tremor (ET)
Essential Tremor is the most common hyperkinetic movement disorder. When it occurs amongst relatives, it may be called “Familial Tremor.”
- The tremor of ET is an involuntary rhythmic oscillation around a joint, most typically in the hand but occasionally in the head.
- This tremor is a postural and kinetic tremor. This means that it is not present at rest, but present if the hand is maintained outstretched in a posture or actively moving towards a target.
- This often is noted when holding a beverage or food, writing, or manipulating objects.
- This tremor may be improved by alcohol and worsened by stress and caffeine.
- The tremor tends to gradually worsen over time. When it begins to interfere with activities of daily living or quality of life, treatment can be pursued.
- There are several classes of medications which can be effective in treating ET. The most common classes are beta-blockers (such as propranolol) or anti-epileptics (such as primidone or topiramate). Occasionally, benzodiazepines (such as clonazepam) may be used.
- Botox injections can occasionally be considered.
- In severe cases, Deep Brain Stimulation can be pursued.
- Weighted utensils or specialized writing instruments can be considered to improve function
Tics are brief purposeless movements, which are often repetitive. These are common, especially in children. In contrast to other conditions, these can be suppressed – or stopped – with concentration. Tics are considered to have partially voluntary control. These may occur more in times of stress.
Tics themselves do not require treatment, unless they are troublesome to the person experiencing them.
A wide variety of medications can be attempted for treating tics, each with differing side effect profiles.
Tourette’s syndrome is a neuropsychiatric disorder that starts in childhood and involves motor and phonic (or sound) tics. This tends to improve more in adulthood.
In addition to treating the tics, people with Tourette’s syndrome should be screened for Obsessive-compulsive disorder (OCD) and Attention deficit disorder (ADD), as these often are associated with each other.
Myoclonus is a brief large-amplitude involuntary jerking movement of a muscle group. There can be a wide variety of causes, including kidney problems, liver problems, brain injuries, or seizure activity.
The primary treatment for myoclonus is to address the underlying condition causing the myoclonus.
Tardive dyskinesia (TD)
Tardive dyskinesia involves involuntary movements that are the result of exposure to dopamine receptor blocking drugs. The causative medications can include antispychotics or certain anti-nausea medications.
The most common form of TD with recurrent mouth, lip, or tongue movements. It can also occasionally involve movements of the extremities.
Care should be taken to avoid over-exposure to causative medications, but other medications may be considered to treat these movements once TD is present, such as tetrabenazine or clonazepam.
Dystonia involves sustained muscle contractions in portions of the body, which can result in abnormal postures. One example is cervical dystonia, where the neck may become bent and uncomfortable.
Medications such as trihexyphenidyl may be considered, but often Botox injections are the treatment of choice.
Chorea are a rare involuntary movement that involves non-rhythmic dance-like jerking movements. A variety of rare neurological conditions can result in this, such as Huntington’s disease, Wilson’s disease, or Sydenham’s chorea.