Levodopa Dose Research Articles

Stalevo® : A pioneering treatment for OFF periods in Parkinsons disease.

Enzymatic metabolism is the key determinant of the overall bioavailability, brain penetration, and efficacy of levodopa in the treatment of Parkinsons disease (PD). Enzyme inhibitors in the form of peripheral dopa-decarboxylase inhibitors and monoamine oxidase type-B inhibitors have been successfully employed to maximize the utility of levodopa in both early- and late-stage PD. However, another major pathway of the peripheral metabolism of levodopa through catechol-O-methyltransferase (COMT) remains unchecked by those measures. Consequently, this becomes a major factor in determining the extent of delivery to the brain. The introduction of tolcapone as a potent and effective peripheral and central COMT inhibitor was frustrated by the emergence of hepatic toxicity. Only with the subsequent introduction of entacapone as an effective inhibitor of peripheral COMT activity has it become possible to fully control the peripheral metabolism of levodopa and to optimize its delivery to the brain. At a single-dose level of 200 mg, the efficacy of entacapone in reducing OFF time and increasing ON time has led to its widespread use for the treatment of "wearing off". To maximize the efficacy of entacapone and to time-lock its pharmacokinetic profile to that of levodopa, a triple combination of levodopa, carbidopa, and entacapone in the form of Stalevo® that allowed for flexibility in levodopa dosing was introduced early in the 21st century. This pioneering development has been successfully used worldwide for the past 20 years. This review considers the role of all three classes of enzyme inhibitors in PD medicine.

Catechol-O-methyltransferase inhibition with entacapone: Evidence from controlled clinical trials in Parkinson's disease.

Adjunct therapy with the catechol-O-methyltransferase inhibitor entacapone is a first-line approach to treat wearing-off type motor fluctuations in levodopa-treated Parkinson's disease (PD) patients. Five randomized placebo-controlled trials including a total of >1000 patients have established its efficacy, showing increases in ON time between 0.7 and 1.6 h, with corresponding OFF-time reductions. These and other trials also found improvements in ON motor function and quality of life. Additional trials have tested the efficacy of adjunct entacapone in patients either without or with early and mild motor fluctuations and also found enhanced motor control and improved activities of daily living function and quality of life, whereas the STRIDE-PD trial failed to show efficacy of early entacapone use in delaying the onset of dyskinesias. Adjunct entacapone enhances dopaminergic activity and may increase levodopa-induced adverse events like dyskinesias, which can usually be controlled by modest levodopa dose reductions. There is no formal requirement to monitor liver function during entacapone treatment. Entacapone can be a rare cause of lymphocytic colitis with severe diarrhoea and need for treatment discontinuation. In 2003, a triple-combination pill of levodopa, carbidopa, and entacapone (LCE) was first introduced onto the market, and since then proprietary LCE (Stalevo® ) is indicated on the basis of those trials for patients with idiopathic PD to (i) substitute for immediate-release carbidopa/levodopa and entacapone previously administered as individual products or (ii) replace immediate-release carbidopa/levodopa therapy (without entacapone) when patients taking a total daily dose of levodopa of ≤600 mg and not experiencing dyskinesias experience signs and symptoms of end-of-dose wearing off.

Real-world considerations regarding the use of the combination of levodopa, carbidopa, and entacapone (Stalevo® ) in Parkinson's disease.

An important aim in long-term levodopa therapy is to prolong the duration of symptomatic efficacy of each dose without increasing peak plasma concentrations above the threshold for the emergence of dyskinesias. One strategy is to enhance levodopa delivery to the brain by co-administering it with inhibitors of peripheral dopa-decarboxylase and catechol-O-methyltransferase (COMT). Levodopa, carbidopa and entacapone (LCE), available in a range of fixed-dose combinations as the branded formulation Stalevo® (Orion Pharma), has been developed to address this requirement and has been in general use for 20 years, having first been evaluated in randomized controlled trials. Experience with LCE has established that improved levodopa pharmacokinetics achieved with dual-enzyme inhibition are translated into improved clinical efficacy, including the possibility of reducing total levodopa dosage with no loss of therapeutic effect. The ease and tolerability of switching to LCE has been affirmed in the SIMCOM trial and by personal experience detailed in this review. Some 300,000 patient-years of safety data are available for LCE, including trial data for up to 5 years. Most adverse effects associated with LCE are attributable to the levodopa component rather than the enzyme inhibitors. The hepatotoxicity observed with the class comparator tolcapone has not been observed with entacapone, the COMT inhibitor in LCE, and there is no formal requirement to monitor liver function during LCE therapy. Other common side effects include diarrhoea, which is one of the more prominent non-dopaminergic adverse events, and urine discolouration, which is harmless but about which patients may require reassurance.

Effects of Tiliroside and Lisuride Co-Treatment on the PI3K/Akt Signal Pathway: Modulating Neuroinflammation and Apoptosis in Parkinson's Disease.

Researchers are actively exploring potential bioactive compounds to enhance the effectiveness of Lisuride (Lis) in treating Parkinson's disease (PD) over the long term, aiming to mitigate the serious side effects associated with its extended use. A recent study found that combining the dietary flavonoid Tiliroside (Til) with Lis has potential anti-Parkinson's benefits. The study showed significant improvements in PD symptoms induced by 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) when Til and Lis were given together, based on various behavioral tests. This combined treatment significantly improved motor function and protected dopaminergic neurons in rats with PD induced by MPTP. It also activated important molecular pathways related to cell survival and apoptosis control, as indicated by the increased pAkt/Akt ratio. Til and Lis together increased B-cell lymphoma 2 (Bcl-2), decreased caspase 3 activity, and prevented brain cell decay. Co-administration also reduced tumor necrosis factor alpha (TNF-α) and Interleukin-1 (IL-1). Antioxidant markers such as superoxide dismutase (SOD), catalase, and reduced glutathione significantly improved compared to the MPTP-induced control group. This study shows that using Til and Lis together effectively treats MPTP-induced PD in rats, yielding results comparable to an 8 mg/kg dose of levodopa, highlighting their potential as promising Parkinson's treatments.

Antagonism of kappa opioid receptors accelerates the development of L-DOPA-induced dyskinesia in a preclinical model of moderate dopamine depletion

Levels of the opioid peptide dynorphin, an endogenous ligand selective for kappa-opioid receptors (KORs), its mRNA and pro-peptide precursors are differentially dysregulated in Parkinson’s disease (PD) and following the development of l-DOPA-induced dyskinesia (LID). It remains unclear whether these alterations contribute to the pathophysiological mechanisms underlying PD motor impairment and the subsequent development of LID, or whether they are part of compensatory mechanisms. We sought to investigate nor-BNI, a KOR antagonist, 1) in the dopamine (DA)-depleted PD state, 2) during the development phase of LID, and 3) via measuring of tonic levels of striatal DA. While nor-BNI (3 mg/kg; s.c.) did not lead to functional restoration in the DA-depleted state, it affected the dose-dependent development of abnormal voluntary movements (AIMs) in response to escalating doses of l-DOPA in a rat PD model with a moderate striatal 6-hydroxdopamine (6-OHDA) lesion. We tested five escalating doses of l-DOPA (6, 12, 24, 48, 72 mg/kg; i.p.), and nor-BNI significantly increased the development of AIMs at the 12 and 24 mg/kg l-DOPA doses. However, after reaching the 72 mg/kg l-DOPA, AIMs were not significantly different between control and nor-BNI groups. In summary, while blocking KORs significantly increased the rate of development of LID induced by chronic, escalating doses of l-DOPA in a moderate-lesioned rat PD model, it did not contribute further once the overall severity of LID was established. While we observed an increase of tonic DA levels in the moderately lesioned dorsolateral striatum, there was no tonic DA change following administration of nor-BNI.

Limiting Monoamines Degradation Increases L-DOPA Pro-Locomotor Action in Newborn Rats.

L-DOPA, the precursor of catecholamines, exerts a pro-locomotor action in several vertebrate species, including newborn rats. Here, we tested the hypothesis that decreasing the degradation of monoamines can promote the pro-locomotor action of a low, subthreshold dose of L-DOPA in five-day-old rats. The activity of the degrading pathways involving monoamine oxidases or catechol-O-methyltransferase was impaired by injecting nialamide or tolcapone, respectively. At this early post-natal stage, the capacity of the drugs to trigger locomotion was investigated by monitoring the air-stepping activity expressed by the animals suspended in a harness above the ground. We show that nialamide (100 mg/kg) or tolcapone (100 mg/kg), without effect on their own promotes maximal expression of air-stepping sequences in the presence of a sub-effective dose of L-DOPA (25 mg/kg). Tissue measurements of monoamines (dopamine, noradrenaline, serotonin and some of their metabolites) in the cervical and lumbar spinal cord confirmed the regional efficacy of each inhibitor toward their respective enzyme. Our experiments support the idea that the raise of monoamines boost L-DOPA's locomotor action. Considering that both inhibitors differently altered the spinal monoamines levels in response to L-DOPA, our data also suggest that maximal locomotor response can be reached with different monoamines environment.

Levodopa Prescription Patterns in Patients with Advanced Parkinson's Disease: A Japanese Database Analysis.

Prescription doses of levodopa in patients with advanced Parkinson's disease (PD) are generally lower in Japan than in the United States or Europe, although Japanese guidelines for the management of PD recommend increasing the dosage as the disease progresses. However, data regarding levodopa prescription practices in patients with advanced PD in the clinical setting are limited. This retrospective observational study analyzed patterns of drug use for patients with advanced PD in Japan using claims data from hospitalized patients in the Medical Data Vision Co. database. Eligible patients had at least two PD-associated claims in two different quarters between April 1, 2008, and November 30, 2018, and a 10-item activities of daily living score <60 upon hospital discharge (as a proxy for advanced PD). The primary endpoint was the prescribed dosage of levodopa at the index hospitalization. Dosages of other PD drugs (medications with an on-label indication for PD) and non-PD drugs were also assessed. Overall, 4029 patients met the inclusion criteria (mean age, 76.9 years; 83.3% aged ≥70 years). At the index date, 74.0% were receiving levodopa. Patients received a median of one PD drug in addition to levodopa, and 27.4% and 20.2% received one or two concomitant PD drugs, respectively. Patients received a median of two non-PD drugs. The median levodopa dosage and total levodopa equivalent dosage (LED) at the index hospitalization were 418.2 and 634.8 mg/day (adjusted for body weight, 9.0 and 13.7 mg/kg/day), respectively. The median levodopa and total LED dosage in each 6-month increment during the 5 years before and after the index date ranged between 263.9 and 330.2 mg/day (5.0 and 6.5 mg/kg/day) and 402.0 and 504.9 mg/day (8.3 and 10.1 mg/kg/day), respectively. This study suggests that many Japanese patients with advanced PD could receive more intensive treatment with higher doses of levodopa.

Model-based optimization of controlled release formulation of levodopa for Parkinson’s disease

Levodopa is currently the standard of care treatment for Parkinson’s disease, but chronic therapy has been linked to motor complications. Designing a controlled release formulation (CRF) that maintains sustained and constant blood concentrations may reduce these complications. Still, it is challenging due to levodopa’s pharmacokinetic properties and the notion that it is absorbed only in the upper small intestine (i.e., exhibits an “absorption window”). We created and validated a physiologically based mathematical model to aid the development of such a formulation. Analysis of experimental results using the model revealed that levodopa is well absorbed throughout the entire small intestine (i.e., no “absorption window”) and that levodopa in the stomach causes fluctuations during the first 3 h after administration. Based on these insights, we developed guidelines for an improved CRF for various stages of Parkinson’s disease. Such a formulation is expected to produce steady concentrations and prolong therapeutic duration compared to a common CRF with a smaller dose per day and a lower overall dose of levodopa, thereby improving patient compliance with the dosage regime.

253 An audit of the inpatient management of Parkinson’s Disease medication in a level four hospital in 2019

Abstract Background Parkinson’s Disease (PD) is a progressive, complex neurodegenerative disease characterised by both motor and non-motor symptoms. PD medications are time sensitive, and their correct prescription and administration are crucial in optimal management strategies. Previous work presented at the Irish Gerontological Society showed a lack of knowledge regarding PD and its medications among healthcare staff in a level four hospital. Methods Data were collected from a retrospective chart analysis of PD admissions in 2019. 115 admissions coded PD were identified from HIPE data. Subsequently, 10 patients were randomly selected from medical, surgical, and orthopaedic admissions respectively (39 admissions). Patients were excluded if they were not on PD-specific medications or if their drug Kardex was not available. 28 patient Kardex’s were reviewed. Data was collected using a predetermined spreadsheet and analysed using Microsoft Excel. Results 100% of patients were on levodopa medication. 86% of patients did not receive their appropriate PD medications in the Emergency department. 21% had errors in medication prescription (omitted drug [n = 4, 14%], incorrect timings [n = 2, 7%]) on admission. 75% missed at least one dose of levodopa. 83 doses of levodopa were missed across the 28 admissions. 40% were because the patient was nil by mouth (NPO), while 21% had no reason documented. 64% of patients had doses of levodopa delayed by more than 1 hour, with over 80% of these in the perioperative period. 5 patients (18%) received antidopaminergic drugs. Conclusion This review highlighted multiple shortcomings in PD medication management during acute admissions. We introduced hospital guidelines for the management of patients with PD while NPO. This guideline includes information on alternatives to oral route, advice regarding the perioperative period, and medications to avoid. It has been approved by the Medications and Therapeutics committee and will be introduced with education sessions at the changeover. We will reaudit practices after 6 months.

D2 dopamine receptors and the striatopallidal pathway modulate L-DOPA-induced dyskinesia in the mouse

L-DOPA-induced dyskinesia (LID) remains a major complication of Parkinson's disease management for which better therapies are necessary. The contribution of the striatonigral direct pathway to LID is widely acknowledged but whether the striatopallidal pathway is involved remains debated. Selective optogenetic stimulation of striatonigral axon terminals induces dyskinesia in mice rendered hemiparkinsonian with the toxin 6-hydroxydopamine (6-OHDA). Here we show that optogenetically-induced dyskinesia is increased by the D2-type dopamine receptor agonist quinpirole. Although the quinpirole effect may be mediated by D2 receptor stimulation in striatopallidal neurons, alternative mechanisms may be responsible as well. To selectively modulate the striatopallidal pathway, we selectively expressed channelrhodopsin-2 (ChR2) in D2 receptor expressing neurons by crossing D2-Cre and ChR2-flox mice. The animals were rendered hemiparkinsonian and implanted with an optic fiber at the ipsilateral external globus pallidus (GPe). Stimulation of ChR2 at striatopallidal axon terminals reduced LID and also general motility during the off L-DOPA state, without modifying the pro-motor effect of low doses of L-DOPA producing mild or no dyskinesia. Overall, the present study shows that D2-type dopamine receptors and the striatopallidal pathway modulate dyskinesia and suggest that targeting striatopallidal axon terminals at the GPe may have therapeutic potential in the management of LID.

Unilateral focused ultrasound subthalamotomy in early Parkinson’s disease: a pilot study

BackgroundUnilateral focused ultrasound subthalamotomy (FUS-STN) improves motor features of Parkinson’s disease (PD) in moderately advanced patients. The less invasive nature of FUS makes its early application in PD feasible. We...

End of life care of hospitalized patients with Parkinson disease: a retrospective analysis and brief review.

Towards the end of life (EOL), persons with parkinsonism (PwP) have complex needs and can present with unique palliative care (PC) challenges. There are no widely accepted guidelines to aid neurologists, hospitalists, or PC clinicians in managing the symptoms of PwP at EOL. We examined a population of PwP at EOL, aiming to describe trends of in-hospital management and utilization of PC services. All PwP admitted to two hospitals during 2018 (N = 727) were examined retrospectively, assessing those who died in hospital or were discharged with hospice (EOL group, N = 35) and comparing them to the main cohort. Their demographics, clinical data, engagement of multidisciplinary and palliative services, code status changes, invasive care, frequency of admissions, and medication administration were assessed. Among the EOL group, 8 expired in hospital, and 27 were discharged to hospice. Forty-six percent of EOL patients received a PC consultation during their admission. The median interval from admission to death was 37 days. Seventy-seven percent had a full code status on admission. Compared to hospice patients, those who expired in hospital had higher rates of invasive procedures and intensive care unit transfers (41% vs. 75%, in both variables), and lower rates of PC involvement (52% vs. 25%). The transition of code status change for the EOL group from Full code to Do Not Resuscitate (DNR) occurred at a median 4-5 days from admission. For patients that passed in the hospital, the median days from transition of code status to death was 0(IQR 0-1). Levodopa dose deviations were frequent in both EOL and non-EOL group, but contraindicated medications were infrequently administered (11% in EOL group vs. 9% in non-EOL group). Our data suggest a low utilization of PC services and delayed discussions of goals of care. More work is needed to raise awareness of inpatient teams managing PwP regarding the unique but common challenges facing PwP with advanced disease. A brief narrative review summarizing the suggested management of symptoms common to hospitalized PwP near EOL is provided.

The influence of substrates addition order on colorimetric assay based on MnO2 nanocubes: A novel turn-off H2O2 assay strategy in water-soak foods.

Herein, novel MnO2 nanocubes were facilely synthesized by manipulating the dosage of KMnO4 and l-Dopa with the aid of ultrasound. The as-prepared MnO2 nanocubes exhibited interesting oxidation activity which was influenced by the addition order of substrates (H2O2 and 3,3,5,5-tetramethylbenzidine (TMB)). After the mechanism study, we found that H2O2 and TMB can be competitively oxidized by MnO2 nanocubes, which was different from the peroxidase- and oxidase-like activities. According to the discovery, a novel turn-off H2O2 assay method based on MnO2 nanocubes was established, where H2O2 was firstly incubated with MnO2 nanocubes for 3min and then TMB was added for the instantaneous chromogenic reaction. In addition to the shorter operation time, the colorimetric results were less affected by temperature and unchanged within 30min without terminating reaction. Moreover, the method showed ultra-high sensitivity with low limit of detection (0.027μmol L-1) and acceptable reliability for H2O2 assay in water-soak foods.

The role of opicapone in the management of Parkinson's disease: an Italian consensus through a combined Nominal Group Technique and Delphi approach.

Opicapone (OPC) is a third-generation peripheral catechol-O-methyl transferase inhibitor (COMT-i) approved as add-on therapy to levodopa/DOPA decarboxylase inhibitors (DDCI) combinations in Parkinson's disease (PD) patients with end-of-dose motor fluctuations. While the OPC effectiveness on motor symptoms is well known, there is still uncertainty about the timing of introduction, the management of levodopa dose, and the efficacy on non-motor symptoms (NMS). A group of PD experts participated in a consensus activity composed of the Nominal Group Technique (NGT) and the Delphi method to better define the role of OPC. A list of statements was defined with the NGT and voted on through an online Delphi process by a panel of 85 Italian clinicians. 24 statements were selected for the Delphi voting. Most statements (n=15, 62%) reached a consensus. A wide agreement was reached about the efficacy of OPC in treating motor fluctuations, including early morning akinesia and nocturnal akinesia. The panel widely agreed about the effectiveness of OPC in early fluctuating patients. The long-lasting inhibitory effect of OPC was recognized as an advantage over other COMT-i, resulting in a single daily dose and greater ease of introduction into the levodopa therapeutic regimen. The efficacy of OPC observed in the clinical trials for the management of PD patients with motor fluctuations is also experienced in clinical practice. The review of the current positioning of OPC from the late to early stages of the disease may represent an important step in the evolution of the PD therapeutic approach.

Levodopa/Carbidopa to Augment the Treatment of Amblyopia: A Report by the American Academy of Ophthalmology

To review the published literature on the use of levodopa/carbidopa to augment the treatment of amblyopia. Literature searches for English language studies were last conducted in October 2022 in the PubMed database with no date restrictions. The combined searches yielded 55 articles, of which 23 were reviewed in full text. Twelve of these were considered appropriate for inclusion in this assessment and were assigned a level of evidence rating by the panel methodologist. Nine studies were rated level I, and 3 studies were rated level II; there were no level III studies. The duration of treatment was limited to 3 to 16 weeks because of concern about long-term adverse effects such as tardive dyskinesia. This complication was not reported in any of the study participants. The dose of levodopa ranged from 1.5 to 8.3 mg/kg/day, generally divided into 3 daily doses. The carbidopa dose was approximately 25% of the levodopa dose in all treatments. Evidence from these studies indicates that augmenting traditional patch occlusion therapy with the oral administration of levodopa/carbidopa can improve the vision of amblyopic children, but the effect was small (0.17-0.3 logarithm of the minimum angle of resolution [logMAR] units) and only statistically significant when compared with patching alone in 2 of the 12 studies cited. Regression of vision was reported in the majority of studies (9 of 12 reported; range, 0-0.17 logMAR unit regression) after discontinuation of therapy. Short-term side effects of the medications were not consistently reported but were most frequently mild and included headache and nausea. The best available evidence is currently insufficient to show that augmenting amblyopia therapy using up to 16 weeks of levodopa/carbidopa will result in meaningful improvement in visual acuity. Given the potential for significant side effects such as tardive dyskinesia with long-term therapy, levodopa/carbidopa does not appear to be a viable option for amblyopia therapy FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Catecholamines and Parkinson's disease: tyrosine hydroxylase (TH) over tetrahydrobiopterin (BH4) and GTP cyclohydrolase I (GCH1) to cytokines, neuromelanin, and gene therapy: a historical overview.

The author identified the genes and proteins of human enzymes involved in the biosynthesis of catecholamines (dopamine, norepinephrine, epinephrine) and tetrahydrobiopterin (BH4): tyrosine hydroxylase (TH), aromatic L-amino acid decarboxylase (AADC), dopamine β-hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), and GTP cyclohydrolase I (GCH1). In Parkinson's disease (PD), the activities and levels of mRNA and protein of all catecholamine-synthesizing enzymes are decreased, especially in dopamine neurons in the substantia nigra. Hereditary GCH1 deficiency results in reductions in the levels of BH4 and the activities of TH, causing decreases in dopamine levels. Severe deficiencies in GCH1 or TH cause severe decreases in dopamine levels leading to severe neurological symptoms, whereas mild decreases in TH activity in mild GCH1 deficiency or in mild TH deficiency result in only modest reductions in dopamine levels and symptoms of DOPA-responsive dystonia (DRD, Segawa disease) or juvenile Parkinsonism. DRD is a treatable disease and small doses of L-DOPA can halt progression. The death of dopamine neurons in PD in the substantia nigra may be related to (i) inflammatory effect of extra neuronal neuromelanin, (ii) inflammatory cytokines which are produced by activated microglia, (iii) decreased levels of BDNF, and/or (iv) increased levels of apoptosis-related factors. This review also discusses progress in gene therapies for the treatment of PD, and of GCH1, TH and AADC deficiencies, by transfection of TH, AADC, and GCH1 via adeno-associated virus (AAV) vectors.

Impulse Control Disorders in the Polish Population of Patients with Parkinson's Disease.

Background and Objectives: Parkinson's disease (PD) is one of the most common neurodegenerative diseases in the world. It is characterized by the presence of not only typical motor symptoms but also several less known and aware non-motor symptoms (NMS). The group of disorders included in the NMS is Impulse Control Disorders (ICDs). ICDs are a group of disorders in which patients are unable to resist temptations and feel a strong, pressing desire for specific activities such as gambling, hypersexuality, binge eating, and compulsive buying. The occurrence of ICDs is believed to be associated primarily with dopaminergic treatment, with the use of dopamine agonists (DA), and to a lesser extent with high doses of L-dopa. The aim of our study was to develop a profile of Polish ICDs patients and assess the frequency of occurrence of ICDs, as well as determine the risk factors associated with these disorders against the background of the PD population from other countries. Materials and Methods: Our prospective study included 135 patients with idiopathic PD who were hospitalized between 2020 and 2022 at the Neurological Department of University Central Hospital in Katowice. In the assessment of ICDs, we used the Questionnaire for Impulsive-Compulsive Disorders in Parkinson's Disease (QUIP). Other scales with which we assessed patients with PD were as follows: MDS-UPDRS part III and modified Hoehn-Yahr staging. Clinical data on age, gender, disease duration and onset, motor complications, and medications were collected from electronic records. Results: ICDs were detected in 27.41% of PD patients (binge eating in 12.59%, hypersexuality in 11.11%, compulsive buying in 10.37%, and pathological gambling occurred in only 5.19% of patients. In total, 8.89% had two or more ICDs). The major finding was that ICDs were more common in patients taking DA than in those who did not use medication from this group (83.78% vs. 54.07%, respectively; p = 0.0015). Patients with ICDs had longer disease duration, the presence of motor complications, and sleep disorders. An important finding was also a very low detection of ICDs in a routine medical examination; only 13.51% of all patients with ICDs had a positive medical history of this disorder. Conclusions: ICDs are relatively common in the population of Polish PD patients. The risk factors for developing ICDs include longer duration of the disease, presence of motor complications, sleep disorders, and use of DA and L-dopa. Due to the low detectability of ICDs in routine medical history, it is essential for physicians to pay more attention to the possibility of the occurrence of these symptoms, especially in patients with several risk factors. Further prospective studies on a larger group of PD patients are needed to establish a full profile of Polish PD patients with ICDs.

Investigation of PRKN Mutations in Levodopa-Induced Dyskinesia in Parkinson's Disease Treatment.

Mitophagy is an important process that participates in mitochondrial quality control. Dysfunctions in this process can be caused by mutations in genes like PRKN and are associated with the development and progression of Parkinson's Disease (PD). The most used drug in the treatment of PD is levodopa (LD), but it can cause adverse effects, such as dyskinesia. Currently, few studies are searching for biomarkers for an effective use of lLD for this disease, especially regarding mitophagy genetics. Thus, this work investigates the association of 14 variants of the PRKN gene with LD in the treatment of PD. We recruited 70 patients with PD undergoing treatment with LD (39 without dyskinesia and 31 with dyskinesia). Genotyping was based on Sanger sequencing. Our results reinforce that age at onset of symptoms, duration of PD, and treatment and dosage of LD can influence the occurrence of dyskinesia but not the investigated PRKN variants. The perspective presented here of variants of mitophagy-related genes in the context of treatment with LD is still underexplored, although an association has been indicated in previous studies. We suggest that other variants in PRKN or in other mitophagy genes may participate in the development of levodopa-induced dyskinesia in PD treatment.

Monitoring the Effect of Levodopa Using Sustained Phonemes in Parkinson's Disease Patients.

Parkinson's disease (PD) is a neurological disease identified by multiple symptoms, and levodopa is one of the most effective medications for treating the disease. To determine the dosage of levodopa, it is necessary to meet on a regular basis and observe motor function. The early detection and progression of the disease have been proposed using hypokinetic dysarthria. However, previous studies have not examined the effects of levodopa on speech rigorously and have provided inconsistent results. In this study, three sustained phonemes of PD patients were investigated for the effect of medication. A set of features characterizing vocal fold dynamics as well as the vocal tract coordinators were extracted from the sustained phonemes /of 28 PD patients during levodopa medication off and on states. All the features were statistically investigated and classified using a linear discriminant analysis (LDA) classifier. LDA classifier identified medication on from medication off based on the combined features from phoneme /a/, /o/ and /m/ with the accuracy=82.75% and F1-score=82.18%. Voice recording of PD patients during sustained phonemes /a/, /o/ and /m/ has the potential for identifying whether the patients are in On state or Off state of medication.Clinical Relevance- The outcomes of this study have the potential to monitor the effect and progress of levodopa on PD patients.

Importance of time to ON versus wearing OFF in total daily OFF time experienced by patients with Parkinson's disease

Most patients with Parkinson's disease (PD) receiving levodopa (LD)/DOPA decarboxylase inhibitors develop motor fluctuations with an increasing amount of OFF time, negatively impacting patient quality of life. Herein, we review the evidence supporting the substantial, yet underappreciated contribution of delays in time to ON (including delayed ON and no ON) to total daily OFF time. Most clinical studies use patient diaries that do not capture time to ON and wearing OFF separately as related to LD dosing, and consequently, most OFF time has generally been attributed to wearing OFF. Hence, most treatment regimens focus on reducing wearing OFF by changing LD dosing/formulations and/or using “ON-extenders” (eg, catechol-o-methyltransferase inhibitors, monoamine oxidase-B inhibitors, extended-release amantadine, and adenosine A2A receptor antagonists). However, the literature describing approved treatments for PD that has focused on delays in time to ON is sparse and suggests this type of OFF may comprise more than twice the amount of total daily OFF time as wearing OFF. Here, we advocate for the importance of measuring and adequately addressing delays in time to ON and build support for the consistent inclusion of the time to ON measurement in future clinical trials.