Made by DATEXIS (Data Science and Text-based Information Systems) at Beuth University of Applied Sciences Berlin
Deep Learning Technology: Sebastian Arnold, Betty van Aken, Paul Grundmann, Felix A. Gers and Alexander Löser. Learning Contextualized Document Representations for Healthcare Answer Retrieval. The Web Conference 2020 (WWW'20)
Funded by The Federal Ministry for Economic Affairs and Energy; Grant: 01MD19013D, Smart-MD Project, Digital Technologies
There is no known cure for PSP and management is primarily supportive. PSP cases are often split into two subgroups, PSP-Richardson, the classic type, and PSP-Parkinsonism, where a short-term response to levodopa can be obtained. Dyskinesia is an occasional but rare complication of treatment. Amantadine is also sometimes helpful. After a few years the Parkinsonian variant tends to take on Richardson features. Other variants have been described. Botox can be used to treat neck dystonia and blephrospasm, but this can aggravate dysphagia.
Two studies have suggested that rivastigmine may help with cognitive aspects, but the authors of both studies have suggested a larger sampling be used. There is some evidence that the hypnotic zolpidem may improve motor function and eye movements, but only from small-scale studies.
Patients with PSP usually seek or are referred to occupational therapy, speech-language pathology for motor speech changes typically a spastic-ataxic dysarthria, and physical therapy for balance and gait problems with reports of frequent falls. Evidence-based approaches to rehabilitation in PSP are lacking, and currently the majority of research on the subject consists of case reports involving only a small number of patients.
Case reports of rehabilitation programs for patients with PSP generally include limb-coordination activities, tilt-board balancing, gait training, strength training with progressive resistive exercises and isokinetic exercises and stretching of the neck muscles. While some case reports suggest that physiotherapy can offer improvements in balance and gait of patients with PSP, the results cannot be generalized across all patients with PSP as each case report only followed one or two patients. The observations made from these case studies can be useful, however, in helping to guide future research concerning the effectiveness of balance and gait training programs in the management of PSP.
Individuals with PSP are often referred to occupational therapists to help manage their condition and to help enhance their independence. This may include being taught to use mobility aids. Due to their tendency to fall backwards, the use of a walker, particularly one that can be weighted in the front, is recommended over a cane. The use of an appropriate mobility aid will help to decrease the individual’s risk of falls and make them safer to ambulate independently in the community.
Due to their balance problems and irregular movements individuals will need to spend time learning how to safely transfer in their homes as well as in the community. This may include rising from and sitting in chairs safely.
Due to the progressive nature of this disease, all individuals eventually lose their ability to walk and will need to progress to using a wheelchair. Severe dysphagia often follows, and at this point death is often a matter of months.
Methylphenidate, commonly used to treat ADHD, has been used in conjunction with levodopa to treat hypokinesia in the short term. The two work together to increase dopamine levels in the striatum and prefrontal cortex. Methylphenidate mainly inhibits dopamine and noradrenaline reuptake by blocking presynaptic transporters, and levodopa increases the amount of dopamine, generally improving hypokinesic gait. Some patients, however, have adverse reactions of nausea and headache to the treatment and the long-term effects of the drug treatment still need to be assessed.
Tolcapone inhibits the activity COMT, an enzyme which degrades dopamine. It has been used to complement levodopa; however, its usefulness is limited by possible complications such as liver damage. A similarly effective drug, entacapone, has not been shown to cause significant alterations of liver function. Licensed preparations of entacapone contain entacapone alone or in combination with carbidopa and levodopa.
Not all individuals with ET require treatment, but there are many treatment options depending on symptom severity. Caffeine and stress should be avoided, and good sleep is recommended.
When symptoms are sufficiently troublesome to warrant treatment, the first medication choices are beta blockers such as propranolol or alternately, nadolol and timolol. Atenolol and pindolol are not effective for tremor. The anti-epileptic primidone is also effective for ET.
Second-line or third-line medications can be added if the first-line medications do not control the tremor. Second-line medications are the anti-epileptics topiramate, gabapentin (as monotherapy) and levetiracetam, or benzodiazepines like alprazolam. Third-line medications are clozapine and mirtazapine.
Theophylline has been used by some practitioners to treat ET, even though it may also induce tremor. However, its use is debated due to conflicting data on its efficacy. There is some evidence that low doses may lead to improvement.
Ethanol has shown superior efficacy to that of benzodiazepines in small trials. It improves tremor in small doses and its effects are usually noticeable within 20 minutes for 3–5 hours, but occasionally appears a rebound tremor augmentation later.
When medications do not control the tremor or the person does not tolerate medication, botulinum toxin, deep brain stimulation or occupational therapy can be helpful. The electrodes for deep brain stimulation are usually placed in the "tremor center" of the brain, the ventral intermediate nucleus of the thalamus.
Additionally, MRI-guided high intensity focused ultrasound is a non-surgical treatment option for people with essential tremor who have not seen improvement with medication and refused or are not valid candidates for other techniques, such as deep brain stimulation. MRI-guided high intensity focused ultrasound does not achieve healing but can improve the quality of life. However, its safety, efficacy and long-term effects are not yet established. Temporary and permanent adverse side effects have been documented, and also the reappearance of tremors. Possible adverse events include gait difficulties, balance disturbances, paresthesias, headache, hemorrhage in the treated area (which requiries emergency treatment), tissue damage in other areas, skin burns with ulcerations, skin retraction, scars and blood clots. This procedure is contraindicated in pregnant women, persons who have a non-MRI compatible implanted metallic devices, allergy to MR contrast agents, cerebrovascular disease, abnormal bleeding, hemorrhage and/or blood clotting disorders, advanced kidney disease or on dialysis, heart conditions, severe hypertension, ethanol or substance abuse, among others. The US Food and Drug Administration ("FDA") approved Insightec’s Exablate Neuro system to treat essential tremor in 2016.
Several dopamine agonists that bind to dopamine receptors in the brain have similar effects to levodopa. These were initially used as a complementary therapy to levodopa for individuals experiencing levodopa complications (on-off fluctuations and dyskinesias); they are now mainly used on their own as first therapy for the motor symptoms of PD with the aim of delaying the initiation of levodopa therapy and so delaying the onset of levodopa's complications. Dopamine agonists include bromocriptine, pergolide, pramipexole, ropinirole, piribedil, cabergoline, apomorphine and lisuride.
Though dopamine agonists are less effective than levodopa at controlling PD motor symptoms, they are usually effective enough to manage these symptoms in the first years of treatment. Dyskinesias due to dopamine agonists are rare in younger people who have PD but, along with other complications, become more common with older age at onset. Thus dopamine agonists are the preferred initial treatment for younger onset PD, and levodopa is preferred for older onset PD.
Dopamine agonists produce significant, although usually mild, side effects including drowsiness, hallucinations, insomnia, nausea, and constipation. Sometimes side effects appear even at a minimal clinically effective dose, leading the physician to search for a different drug. Agonists have been related to impulse control disorders (such as compulsive sexual activity, eating, gambling and shopping) even more strongly than levodopa. They tend to be more expensive than levodopa.
Apomorphine, a non-orally administered dopamine agonist, may be used to reduce off periods and dyskinesia in late PD. It is administered by intermittent injections or continuous subcutaneous infusions. Since secondary effects such as confusion and hallucinations are common, individuals receiving apomorphine treatment should be closely monitored. Two dopamine agonists that are administered through skin patches (lisuride and rotigotine) and are useful for people in the initial stages and possibly to control off states in those in the advanced state.
Because the exact cause of CBD is unknown, there exists no formal treatment for the disease. Instead, treatments focus on minimizing the appearance or effect of the symptoms resulting from CBD. The most easily treatable symptom of CBD is parkinsonism, and the most common form of treatment for this symptom is the application of dopaminergic drugs. However, in general only moderate improvement is seen and the relief from the symptom is not long-lasting. In addition, palliative therapies, including the implementation of wheelchairs, speech therapy, and feeding techniques, are often used to alleviate many of the symptoms that show no improvement with drug administration.
Since pseudobulbar palsy is a syndrome associated with other diseases, treating the underlying disease may eventually reduce the symptoms of pseudobulbar palsy.
Possible pharmacological interventions for pseudobulbar affect include the tricyclic antidepressants, serotonin reuptake inhibitors, and a novel approach utilizing dextromethorphan and quinidine sulfate. Nuedexta is an FDA approved medication for pseudobulbar affect. Dextromethorphan, an N-methyl-D-aspartate receptor antagonist, inhibits glutamatergic transmission in the regions of the brainstem and cerebellum, which are hypothesized to be involved in pseudobulbar symptoms, and acts as a sigma ligand, binding to the sigma-1 receptors that mediate the emotional motor expression.
New treatments include increasing the number of dopamine cells by transplanting stem cells into the basal ganglia or stimulating endogenous stem cell production and movement to the basal ganglia. The successful integration of stem cells can relieve hypokinetic symptoms and decrease the necessary dose of dopaminergic drugs. However, a variety of complications, including possible tumor formation, inappropriate cell migration, rejection of cells by the immune system, and cerebral hemorrhage are possible, causing many physicians to believe the risks outweigh the possible benefits.
Physical therapists can assist patients in maintaining their level of independence through therapeutic exercise programmes. One recent research report demonstrated a gain of 2 SARA points (Scale for the Assessment and Rating of Ataxia) from physical therapy. In general, physical therapy emphasises postural balance and gait training for ataxia patients. General conditioning such as range-of-motion exercises and muscle strengthening would also be included in therapeutic exercise programmes. Research showed that spinocerebellar ataxia 2 (SCA2) patients with a mild stage of the disease gained significant improvement in static balance and neurological indices after six months of a physical therapy exercise training program. Occupational therapists may assist patients with incoordination or ataxia issues through the use of adaptive devices. Such devices may include a cane, crutches, walker, or wheelchair for those with impaired gait. Other devices are available to assist with writing, feeding, and self care if hand and arm coordination are impaired. A randomised clinical trial revealed that an intensive rehabilitation program with physical and occupational therapies for patients with degenerative cerebellar diseases can significantly improve functional gains in ataxia, gait, and activities of daily living. Some level of improvement was shown to be maintained 24 weeks post-treatment. Speech language pathologists may use both behavioral intervention strategies as well as augmentative and alternative communication devices to help patients with impaired speech.
Idebenone, an antioxidant, was recently removed from the Canadian market in 2013 due to lack of effectiveness. A Cochrane review on antioxidants and other pharmacological treatment of patients with Friedreich ataxia concluded that there is limited but not persuasive evidence of efficacy.
Nicotinamide administration on patients was associated with a sustained improvement in frataxin concentrations towards those seen in asymptomatic carriers during 8 weeks of daily dosing. The daily oral administration of 3.8 g nicotinamide resulted in a 1.5-times increase, whereas 7.5 g resulted in a doubling of frataxin protein concentration.
There is no cure for spinocerebellar ataxia, which is currently considered to be a progressive and irreversible disease, although not all types cause equally severe disability.
In general, treatments are directed towards alleviating symptoms, not the disease itself. Many patients with hereditary or idiopathic forms of ataxia have other symptoms in addition to ataxia. Medications or other therapies might be appropriate for some of these symptoms, which could include tremor, stiffness, depression, spasticity, and sleep disorders, among others. Both onset of initial symptoms and duration of disease are variable. If the disease is caused by a polyglutamine trinucleotide repeat CAG expansion, a longer expansion may lead to an earlier onset and a more radical progression of clinical symptoms. Typically, a person afflicted with this disease will eventually be unable to perform daily tasks (ADLs). However, rehabilitation therapists can help patients to maximize their ability of self-care and delay deterioration to certain extent. Researchers are exploring multiple avenues for a cure including RNAi and the use of Stem Cells and several other avenues.
On January 18, 2017 BioBlast Pharma announced completion of Phase 2a clinical trials of their medication, Trehalose, in the treatment of SCA3. BioBlast has received FDA Fast Track status and Orphan Drug status for their treatment. The information provided by BioBlast in their research indicates that they hope this treatment may prove efficacious in other SCA treatments that have similar pathology related to PolyA and PolyQ diseases.
In addition, Dr. Beverly Davidson has been working on a methodology using RNAi technology to find a potential cure for over 2 decades. Her research began in the mid-1990s and progressed to work with mouse models about a decade later and most recently has moved to a study with non-human primates. The results from her most recent research "are supportive of clinical application of this gene therapy". Dr. Davidson along with Dr. Pedro Gonzalez-Alegre are currently working to move this technique into a Phase 1 clinical trial.
Finally, another gene transfer technology discovered in 2011 has also been shown by Dr. Davidson to hold great promise and offers yet another avenue to a potential future cure.
Parkinson-plus syndromes are usually more rapidly progressive and less likely to respond to antiparkinsonian medication than PD. However, the additional features of the diseases may respond to medications not used in PD.
Current therapy for Parkinson-plus syndromes is centered around a multidisciplinary treatment of symptoms.
These disorders have been linked to pesticide exposure.
Attention strategies:
By consciously paying more attention to walking and rehearsing each step before actually making it, PD patients have shown to improve their gait. Sometimes, a companion walking alongside reminds the patient to concentrate on gait or they create a visual cue to step over by putting a foot in front of the person with PD over which the person must step. This causes the patient to focus their attention on the stepping action, thus making this a voluntary action and hence bypassing the faulty basal ganglia pathway (which is responsible for involuntary actions like walking). Avoidance of dual tasks that require motor attention or cognitive attention has also been shown to normalize gait in the PD patients.
Exercise:
Physical therapy and exercise have been shown to have positive effects on gait parameters in PD patients.
Physiotherapists may help improve gait by creating training programs to lengthen a patient's stride length, broaden the base of support, improve the heel-toe gait pattern, straighten out a patient's posture, and increase arm swing patterns.
Research has shown gait training combining an overhead harness with walking on a treadmill has shown to improve both walking speed and stride length. The harness assists the patient in maintaining an upright posture by eliminating the need to use a mobility aid, a practice which normally promotes a forward flexed posture. It is believed the activation of the central pattern generator leads to the improvement in gait pattern.
Improving trunk flexibility, along with strengthening of the core muscles and lower extremities has been associated with increased balance and an improvement in gait pattern. Aerobic exercises such as tandem bicycling and water aerobics are also crucial in improving strength and overall balance. Due to PD’s progressive nature it is important to sustain an exercise routine to maintain its benefits.
Strategies such as using a vertical walking pole can also help to improve upright postural alignment. The therapist may also use tiles or footprints on the ground to improve foot placement and widen the patient's base of support. Creative visualization of walking with a more normalized gait pattern, and mentally rehearsing the desired movement has also shown to be effective.
The patient should also be challenged by walking on a variety of surfaces such as tile, carpet, grass, or foamed surfaces will also benefit the individual’s progress towards normalizing their gait pattern.
No specific treatment is known that would prevent, slow, or reverse HSP. Available therapies mainly consist of symptomatic medical management and promoting physical and emotional well-being. Therapeutics offered to HSP patients include:
- Baclofen – a voluntary muscle relaxant to relax muscles and reduce tone. This can be administered orally or intrathecally. (Studies in HSP )
- Tizanidine – to treat nocturnal or intermittent spasms (studies available )
- Diazepam and clonazepam – to decrease intensity of spasms
- Oxybutynin chloride – an involuntary muscle relaxant and spasmolytic agent, used to reduce spasticity of the bladder in patients with bladder control problems
- Tolterodine tartate – an involuntary muscle relaxant and spasmolytic agent, used to reduce spasticity of the bladder in patients with bladder control problems
- Botulinum toxin – to reduce muscle overactivity (existing studies for HSP patients)
- Antidepressants (such as selective serotonin re-uptake inhibitors, tricyclic antidepressants and monoamine oxidase inhibitors) – for patients experiencing clinical depression
- Physical therapy – to restore and maintain the ability to move; to reduce muscle tone; to maintain or improve range of motion and mobility; to increase strength and coordination; to prevent complications, such as frozen joints, contractures, or bedsores.
Treatment should be based on assessment by relevant health professionals. For spastic muscles with mild-to-moderate impairment, exercise should be the mainstay of management, and is likely needed to be prescribed by an occupational therapist, physical therapist, accredited exercise physiologist (AEP) or other health professional skilled in neurological rehabilitation.
Muscles with severe spasticity are likely to be more limited in their ability to exercise, and may require help to do this. They may require additional interventions, to manage the greater neurological impairment and also the greater secondary complications. These secondary complications involve the development of contractures, deformity and postural asymmetries. Interventions may include icing, serial casting, sustained stretching, inhibitory pressure and medical interventions. Treatment should be done with firm and constant manual contact positioned over nonspastic areas to avoid stimulating the spastic muscle(s). Alternatively, rehabilitation robotics can be used to provide high volumes of passive or assisted movement, depending on the individual's requirements; this form of therapy can be useful if therapists are at a premium, and has been found effective at reducing spasticity in patients suffering from stroke. For muscles that lack any volitional control, such as after complete spinal cord injury, exercise may be assisted, and may require equipment, such as using a standing frame to sustain a standing position. A general treatment guideline can be followed that involves:
- The initial focus on first activating contraction of antagonist muscles to provide reciprocal inhibition and lengthen spastic muscles
- Reciprocal actions are attempted. Agonist contractions are performed first in small ranges progressing to larger arcs of movement
- Highly stressful activities be minimized early in training
- Functional skills are targeted for training
- Patients and family/caregivers should be educated about the importance of maintaining range of motion and doing daily exercises
Medical interventions may include such medications as baclofen, diazepam, dantrolene, or clonazepam. Phenol injections can be used, or botulinum toxin injections into the muscle belly, to attempt to dampen the signals between nerve and muscle. The effectiveness of medications vary between individuals, and vary based on location of the upper motor neuron lesion (in the brain or the spinal cord). Medications are commonly used for spastic movement disorders, but research has not shown functional benefit for some drugs. Some studies have shown that medications have been effective in decreasing spasticity, but that this has not been accompanied by functional benefits. Surgery could be required for a tendon release in the case of a severe muscle imbalance leading to contracture. In spastic CP, selective dorsal rhizotomy has also been used to decrease muscle overactivity.
Incorporating hydrotherapy in the treatment program may help decrease spasm severity, promote functional independence, improve motor recovery and decrease medication required for spasticity, which may help reduce the side effects that are possible with oral drug treatments. A 2004 study compared the effects of hydrotherapy on spasticity, oral baclofen dosage and Functional Independence Measure (FIM) scores of patients with a spinal cord injury (SCI). It was found that subjects who received hydrotherapy treatment obtained increased FIM scores and a decreased intake of oral baclofen medication. A 2009 study looked at the effect of hydrotherapy to decrease spasticity on post-stroke, hemiparetic patients with limited mobility and concluded that there was a significantly larger increase in FIM scores compared to the control group that did not receive hydrotherapy.
Although no cure exists, there are many different treatments which are currently being used to help control symptoms. These include short term treatment with some drugs (such as Botox) which relax the muscles, use of temperature changes to control muscle tremors, and a balanced approach of coordinated care and support involving physical therapists, orthopedic surgeons, and psychiatrists.
Because there is no cure for ataxic cerebral palsy, current methods of treatment are diverse, often consisting of multiple focuses designed to limit the severity of symptoms. Many children suffering from ataxic cerebral palsy are treated by teams consisting of individuals from numerous disciplines, including physical therapists, occupational therapist, orthopedic surgeons, and psychiatrists. Treatment by such teams involves multiple approaches. Providing a primary care medical home to support children suffering from common symptoms of nutritional deficiencies, pain, dental care, bowel and bladder continence, and orthopedic complications is an essential aspect of treatment. In addition, utilizing diagnostic techniques to identify the nature and severity of brain abnormalities has become increasingly beneficial for treatment in recent years.
Different medications have been used to temporarily treat ataxic cerebral palsy. Medications like primidone and benzodiazepine, while not recommended for long term use, can alleviate some of the tremor symptoms. Botox which relaxes tightened muscles has been effective in treating voice, hand and head tremors. A few recently published papers outlined a potential method for treating intention tremor which consisted of cooling the forearm by wrapping it in a cryomanchet using a circulating fluid. After the treatment most patients experienced reduced tremor for up to half an hour. This practical, however short-term treatment can facilitate performing normal daily activities like applying make up, eating, or signing documents. This potential treatment method is also significant in that it reduces one’s reliance on caregivers.
No medications have been shown to prevent or cure dementia. Medications may be used to treat the behavioural and cognitive symptoms but have no effect on the underlying disease process.
Acetylcholinesterase inhibitors, such as donepezil, may be useful for Alzheimer disease and dementia in Parkinson's, DLB, or vascular dementia. The quality of the evidence however is poor and the benefit is small. No difference has been shown between the agents in this family. In a minority of people side effects include a slow heart rate and fainting.
As assessment for an underlying cause of the behavior is a needed before prescribing antipsychotic medication for symptoms of dementia. Antipsychotic drugs should be used to treat dementia only if non-drug therapies have not worked, and the person's actions threaten themselves or others. Aggressive behavior changes are sometimes the result of other solvable problems, that could make treatment with antipsychotics unnecessary. Because people with dementia can be aggressive, resistant to their treatment, and otherwise disruptive, sometimes antipsychotic drugs are considered as a therapy in response. These drugs have risky adverse effects, including increasing the patient's chance of stroke and death. Generally, stopping antipsychotics for people with dementia does not cause problems, even in those who have been on them a long time.
N-methyl-D-aspartate (NMDA) receptor blockers such as memantine may be of benefit but the evidence is less conclusive than for AChEIs. Due to their differing mechanisms of action memantine and acetylcholinesterase inhibitors can be used in combination however the benefit is slight.
While depression is frequently associated with dementia, selective serotonin reuptake inhibitors (SSRIs) do not appear to affect outcomes.
The use of medications to alleviate sleep disturbances that people with dementia often experience has not been well researched, even for medications that are commonly prescribed. In 2012 the American Geriatrics Society recommended that benzodiazepines such as diazepam, and non-benzodiazepine hypnotics, be avoided for people with dementia due to the risks of increased cognitive impairment and falls. Additionally, there is little evidence for the effectiveness of benzodiazepines in this population. There is no clear evidence that melatonin or ramelteon improves sleep for people with dementia due to Alzheimer's disease. There is limited evidence that a low dose of trazodone may improve sleep, however more research is needed.
There is no solid evidence that folate or vitamin B12 improves outcomes in those with cognitive problems. Statins also have no benefit in dementia. Medications for other health conditions may need to be managed differently for a person who also has a diagnosis of dementia. The MATCH-D criteria can help identify ways that a diagnosis of dementia changes medication management for other health conditions. It is unclear if there is a link between blood pressure medication and dementia. There is a possibility that people may experience an increase in cardiovascular-related events if these medications are withdrawn.
Drugs can be used to treat issues related to the Upper Motor Neuron Syndrome. Drugs like Librium or Valium could be used as a relaxant. Drugs are also given to individuals who have recurrent seizures, which may be a separate but related problem after brain injury.
Treatments using intravenous magnesium sulfate have shown to reduce the symptoms of akinetic mutism. In one case, a 59-year-old woman was administered intravenous magnesium sulfate in an attempt to resolve her akinetic mutism. The patient was given 500 mg of magnesium every eight hours, and improvement was seen after 24 hours. She became more verbal and attentive, and treatment was increased to 1000 mg every eight hours as conditions continued to improve.
Multifocal motor neuropathy is normally treated by receiving intravenous immunoglobulin (IVIG), which can in many cases be highly effective, or immunosuppressive therapy with cyclophosphamide or rituximab. Steroid treatment (prednisone) and plasmapheresis are no longer considered to be useful treatments; prednisone can exacerbate symptoms. IVIg is the primary treatment, with about 80% of patients responding, usually requiring regular infusions at intervals of 1 week to several months. Other treatments are considered in case of lack of response to IVIg, or sometimes because of the high cost of immunoglobulin. Subcutaneous immunoglobulin is under study as a less invasive, more-convenient alternative to IV delivery.
Physical therapy (PT) can help improve muscle strength & coordination, mobility (such as standing and walking), and other physical function using different sensorimotor techniques. Physiotherapists can also help reduce shoulder pain by maintaining shoulder range of motion, as well as using Functional electrical stimulation. Supportive devices, such as braces or slings, can be used to help prevent or treat shoulder subluxation in the hopes to minimize disability and pain. Although many individuals suffering from stroke experience both shoulder pain and shoulder subluxation, the two are mutually exclusive. A treatment method that can be implemented with the goal of helping to regain motor function in the affected limb is constraint-induced movement therapy. This consists of constraining the unaffected limb, forcing the affected limb to accomplish tasks of daily living.
The most widely used form of treatment is L-dopa in various forms. L-dopa is able to pass the blood–brain barrier as a prodrug and is decarboxylated in the brain to the neurotransmitter dopamine by the enzyme aromatic-L-amino-acid decarboxylase. In this way, L-DOPA can replace some of the deficit in dopamine seen in Parkinsonism. Due to feedback inhibition, L-dopa results in a reduction in the endogenous formation of L-dopa, and so eventually becomes counterproductive.
Effect on gait parameters:
The stride length and the kinematic parameters (swing velocity, peak velocity) related to the energy are Dopa-sensitive. Temporal parameters (stride and swing duration, stride duration variability), related to rhythm, are Dopa-resistant.
Effect on falls and freezing of gait:
Levodopa treatment decreases the frequency and the akinetic type of FOG, with a tendency
for shorter FOG episodes. Results indicate that this is primarily because L-dopa increases the threshold for FOG to occur but the fundamental pathophysiology for FOG did not change. It has also been shown that other dopamine agonists like ropinirole, pramipexole and pergolide that have a strong affinity to D2 receptors (as opposed to L-dopa which has a strong D1 receptor affinity) increase the frequency of FOGs.
Effects on postural sway:
Parkinson’s disease have abnormal postural sway in stance and treatment with levodopa increases postural sway abnormalities. During movement, it has been shown that early autonomic postural disturbances are only partially corrected while the later occurring postural corrections are not affected by dopamine. These results indicate that non-dopaminergic lesions play a role in postural imbalance in PD patients.
As seen in the case of Elsie Nicks, the puncture or removal of a cyst causing akinetic mutism can relieve symptoms almost immediately. However, if the cyst fills up again, the symptoms can reappear.