Accuracy of acute levodopa challenge for clinical prediction of sustained long-term levodopa response as a major criterion for idiopathic Parkinson's disease diagnosis

A multi-center, randomized, double-blind, sham-stimulation controlled study of transcranial magnetic stimulation with precision navigation for the treatment of multiple system atrophy

BACKGROUND

Multiple system atrophy (MSA) is recognized as an atypical Parkinsonian syndrome, distinguished by a more rapid progression than that observed in Parkinson's disease. Unfortunately, the prognosis for MSA remains poor, with a notable absence of globally recognized effective treatments. Although preliminary studies suggest that transcranial magnetic stimulation (TMS) could potentially alleviate clinical symptoms in MSA patients, there is a significant gap in the literature regarding the optimal stimulation parameters. Furthermore, the field lacks consensus due to the paucity of robust, large-scale, multicenter trials.

METHODS

This investigation is a multi-center, randomized, double-blind, sham-controlled trial. We aim to enroll 96 individuals diagnosed with MSA, categorized into Parkinsonian type (MSA-P) and cerebellar type (MSA-C) according to their predominant clinical features. Participants will be randomly allocated in a 1:1 ratio to either the TMS or sham stimulation group. Utilizing advanced navigation techniques, we will ensure precise targeting for the intervention, applying theta burst stimulation (TBS). To assess the efficacy of TBS on both motor and non-motor functions, a comprehensive evaluation will be conducted using internationally recognized clinical scales and gait analysis. To objectively assess changes in brain connectivity, functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) will be employed as sensitive indicators before and after the intervention.

DISCUSSION

The primary aim of this study is to ascertain whether TBS can alleviate both motor and non-motor symptoms in patients with MSA. Additionally, a critical component of our research involves elucidating the underlying mechanisms through which TBS exerts its potential therapeutic effects.

ETHICS AND DISSEMINATION

All study protocols have been reviewed and approved by the First Affiliated Medical Ethics Committee of the Air Force Military Medical University (KY20232118-F-1).

TRIAL REGISTRATION

Chinese Clinical Trial Registry ChiCTR2300072658. Registered on 20 June 2023.

Definition and diagnosis of Parkinson's disease: guideline "Parkinson's disease" of the German Society of Neurology

BACKGROUND

Accurate definition and operational criteria for diagnosing Parkinson's disease (PD) are crucial for evidence-based, patient-centered care.

OBJECTIVE

To offer evidence-based recommendations for defining and diagnosing PD, incorporating contemporary clinical, imaging, biomarker, and genetic insights.

METHODS

The guideline development began with the steering committee establishing key PICO (patient, intervention, comparison, outcome) questions, which were refined by the coauthors. Systematic literature searches identified relevant studies, reviews, and meta-analyses. Recommendations were drafted, evaluated, optimized, and voted upon by the German Parkinson's Guideline Group.

RESULTS

Parkinson's disease (PD) is now understood to encompass a broader spectrum of etiologies than previously recognized. Advances in molecular pathogenesis, neuroimaging, and early clinical phenotypes suggest that PD is not a uniform disease entity and is often not idiopathic. This necessitates an updated framework for PD definition and diagnosis. The German Society for Neurology now endorses a broader concept of PD, incorporating both idiopathic and hereditary forms, as opposed to the previously narrower concept of "idiopathic Parkinson syndrome." The revised guidelines recommend using the 2015 Movement Disorders Society diagnostic criteria, emphasize the importance of long-term clinical follow-up for improved diagnostic accuracy, and highlight the significance of non-motor symptoms in clinical diagnosis. Specific recommendations are provided for the use of imaging and fluid biomarkers and genetic testing to support the clinical diagnosis.

CONCLUSION

The updated guidelines from the German Society for Neurology enhance diagnostic accuracy for PD, promoting optimized clinical care.

Dopa Responsiveness in Parkinson's Disease

BACKGROUND

Dopaminergic responsiveness is a defining feature of Parkinson's disease (PD). However, there is limited information on how this evolves over time.

OBJECTIVES

To examine serial dopaminergic responses, if there are distinct patterns, and which factors predict these.

METHODS

We analyzed data from the Parkinson's Progression Markers Initiative on repeated dopaminergic challenge tests (≥24.5% defined as a definite response). Growth-mixture modeling evaluated for different response patterns and multinomial logistic regression tested for predictors of these clusters.

RESULTS

1525 dopaminergic challenge tests were performed in 336 patients. At enrolment, mean age was 61.2 years (SD 9.6), 66.4% were male and disease duration was 0.5 years (SD 0.5). 1 to 2 years after diagnosis, 48.0% of tests showed a definite response, but this proportion increased with longer disease duration (51.1-74.3%). We identified 3 response groups: "Striking" (n = 29, 8.7%); "Excellent" (n = 110; 32.7%) and "Modest" (n = 197, 58.6%). Significant differences were as follows: striking responders commenced treatment earlier (P = 0.02), were less likely to be on dopamine agonist monotherapy (P = 0.01), and had better cognition (P < 0.01) and activities of daily living (P = 0.01). Excellent responders had higher challenge doses (P = 0.03) and were more likely to be on combination therapy (P < 0.01).

CONCLUSION

Three distinct patterns of the dopaminergic response were observed. As the proportion of PD cases with definite dopa responsiveness increased over time, the initial treatment response may be an unreliable diagnostic aid.

Stratifying quality of life outcome in subthalamic stimulation for Parkinson's disease

BACKGROUND

Subthalamic nucleus deep brain stimulation (STN-DBS) for Parkinson's disease (PD) improves quality of life (QoL), motor and non-motor symptoms (NMS). However, in previous studies, 43%-49% of patients did not experience clinically relevant postoperative QoL improvement. To inform individualised prediction of postoperative QoL improvement, we developed a stratification analysis of QoL outcomes based on preoperative non-motor total burden, severity of motor progression and motor response in levodopa challenge tests.

METHODS

This was a prospective, open-label, multicentre, international study with a 6-month follow-up. A distribution-based threshold identified 'QoL responders' in the PDQuestionnaire-8 Summary Index (PDQ-8 SI). After baseline stratification based on the NMS Scale, Hoehn and Yahr Scale and levodopa response assessed with the Unified PD Rating Scale-III, we compared postoperative QoL response between these strata. To assess the clinical usefulness and statistical feasibility of stratifications, we compared cumulative distribution function curves, respectively PDQ-8 within-stratum variation.

RESULTS

All main outcomes improved postoperatively. Based on the 8.1 points threshold for clinically meaningful PDQ-8 SI improvement, only 80/161 patients were classified as 'QoL responders'. The absolute risk reductions for QoL non-response among respective non-motor, motor progression and levodopa response strata were 23%, 8% and 3%, respectively. Only non-motor stratification reduced PDQ-8 within-stratum variation compared with the overall cohort.

CONCLUSIONS

Non-motor stratification, but not motor progression or levodopa response stratification, is clinically useful and statistically feasible for personalised preoperative prediction of postoperative QoL outcome of STN-DBS for PD. Our findings highlight that non-motor assessments are necessary components of a case-based, holistic approach of DBS indication evaluations geared towards optimising postoperative QoL outcomes.

TRIAL REGISTRATION NUMBER

GermanClinicalTrialsRegister: #6735.

Parkinson's Disease and Photobiomodulation: Potential for Treatment

Parkinson's disease is the second most common neurodegenerative disease and is increasing in incidence. The combination of motor and non-motor symptoms makes this a devastating disease for people with Parkinson's disease and their care givers. Parkinson's disease is characterised by mitochondrial dysfunction and neuronal death in the substantia nigra, a reduction in dopamine, accumulation of α-synuclein aggregates and neuroinflammation. The microbiome-gut-brain axis is also important in Parkinson's disease, involved in the spread of inflammation and aggregated α-synuclein. The mainstay of Parkinson's disease treatment is dopamine replacement therapy, which can reduce some of the motor signs. There is a need for additional treatment options to supplement available medications. Photobiomodulation (PBM) is a form of light therapy that has been shown to have multiple clinical benefits due to its enhancement of the mitochondrial electron transport chain and the subsequent increase in mitochondrial membrane potential and ATP production. PBM also modulates cellular signalling and has been shown to reduce inflammation. Clinically, PBM has been used for decades to improve wound healing, treat pain, reduce swelling and heal deep tissues. Pre-clinical experiments have indicated that PBM has the potential to improve the clinical signs of Parkinson's disease and to provide neuroprotection. This effect is seen whether the PBM is directed to the head of the animal or to other parts of the body (remotely). A small number of clinical trials has given weight to the possibility that using PBM can improve both motor and non-motor clinical signs and symptoms of Parkinson's disease and may potentially slow its progression.

Diagnostic pitfalls in young onset parkinsonism and its unique challenges: A case report from rural Nepal

Parkinson's disease is a neurodegenerative disease resulting from the loss of dopamine-secreting neurons present in the substantia nigra of the brain. Parkinson's disease is classified as early-onset and late-onset disease based on the time of its presentation. Since young patients with Parkinson's disease have an atypical clinical presentation and have to deal with their careers, raising families, or both at the time of diagnosis and also have a higher risk of drug-related side effects, it poses unique challenges for the patient, clinical team, and community. We present the case of a 40-year-old female with young onset Parkinson's disease from rural Nepal and the challenges faced during and after the disease in a resource-limited setting.

Clinical characteristics and reaction to dopaminergic treatment of drug-naïve patients with Parkinson's disease in central China: A cross sectional study

Background

The symptoms of early Parkinson's disease (PD) are complex and hidden. The aim of this study is to explore and summarize the characteristics of the symptoms of drug naïve patients with PD.

Objectives

and Methods Drug-naïve patients with PD and age-matched healthy controls were recruited from the outpatient clinic of Wuhan Union Hospital. The motor and non-motor symptoms were evaluated for further analysis using Unified Parkinson's Disease Rating Scale (UPDRS) I, II, and III; Sniffin' Sticks Screening 12 test; Mini-Mental State Exam (MMSE); Montreal Cognitive Assessment (MoCA); Hamilton Anxiety Scale (HAMA); and Hamilton Depression Scale (HAMD) scores. The acute levodopa challenge test (ALCT) was adopted to assess the reaction to dopaminergic treatment.

Results

We recruited 80 drug-naïve patients with PD and 40 age-matched healthy controls (HCs). Approximately 53.7% of the patients were females. The mean onset age was 59.96 ± 10.40 years. The mean UPDRS I, II, and III were 2.01 ± 1.90, 6.18 ± 3.68, and 26.13 ± 12.09, respectively. Compared with HCs, PD patients had lower scores in MMSE and MoCA; and higher scores in HAMA and HAMD (p < 0.05). In ALCT, 54 patients showed good responses to levodopa while 26 patients did not. The mean improvement rate of UPDRS III was 34.09% at 120 min.

Conclusion

The motor symptoms of patients with early PD were mild but virous. They also suffered from different non-motor symptoms. In ALCT, about two thirds of patients (54/80) with early PD showed good response to levodopa. Among four aspects of motor symptoms, bradykinesia reacted best to ALCT, while axial symptoms were the worst.

Age as a risk factor for orthostatic hypotension induced by the levodopa challenge test in patients with Parkinson's disease: Results from a single-center trial

BACKGROUND

Hypotension can occur in patients receiving levodopa (L-dopa) treatment for parkinsonism. However, only few studies have focused on the characteristics of orthostatic hypotension (OH) induced by the L-dopa challenge test (LCT). This study aimed to investigate the characteristics and influencing factors of LCT-induced OH in a relatively large sample of patients with Parkinson's disease (PD).

METHODS

Seventy-eight patients with PD without a previous diagnosis of OH underwent the LCT. Blood pressure (BP) in the supine and standing positions was measured before and 2 hours after the LCT. If diagnosed with OH, the patients' BP was monitored again 3 hours after the LCT. The clinical features and demographics of the patients were analyzed.

RESULTS

Eight patients were diagnosed with OH 2 hours after the LCT (median dose of 375 mg L-dopa/benserazide; incidence = 10.3%). One patient without symptoms had OH 3 hours after the LCT. Compared with patients without OH, patients with OH had lower 1- and 3-minutes standing systolic BP and 1-minute standing diastolic BP at baseline and 2 hours after the LCT. Patients in the OH group were of older age (65.31 ± 4.17 years vs 59.74 ± 5.55years) and had lower Montreal Cognitive Assessment scores (17.5 vs 24) and higher L-dopa/benserazide levels (375 [250, 500] mg vs 250 [125, 500] mg). Older age markedly increased the odds of having LCT-induced OH (odds ratio, 1.451; 95% confidence interval, 1.055-1.995; P = .022).

CONCLUSIONS

LCT increased the odds of OH in non-OH PD, causing symptomatic OH in 10.3% of patients in our study, thereby raising safety concerns. Increase in age was observed to be a risk factor for LCT-induced OH in PD patients. A study with a larger sample size is warranted to confirm our results.

TRIAL REGISTRATION NUMBER

Clinical Trials Registry under ChiCTR2200055707.

DATE OF REGISTRATION

January 16, 2022.

Brain Morphometry Associated With Response to Levodopa and Deep Brain Stimulation in Parkinson Disease

OBJECTIVES

Whether treatment response in patients with Parkinson disease depends on brain atrophy is insufficiently understood. The goal of this study is to identify specific atrophy patterns associated with response to dopaminergic therapy and deep brain stimulation.

MATERIALS AND METHODS

In this study, we analyzed the association of gray matter brain atrophy patterns, as identified by voxel-based morphometry, with acute response to levodopa (N = 118) and subthalamic nucleus deep brain stimulation (N = 39). Motor status was measured as a change in points on the Unified Parkinson's Disease Rating Scale III score. Baseline values were obtained before surgery, after cessation of dopaminergic medication for at least 12 hours; response to medication was assessed after administration of a standardized dose of levodopa. Response to deep brain stimulation was measured three months after surgery in the clinical condition after withdrawal of dopaminergic medication.

RESULTS

Although frontoparietal brain gray matter loss was associated with subpar response to deep brain stimulation, there was no significant link between brain atrophy and response to levodopa.

CONCLUSION

We conclude that response to deep brain stimulation relies on gray matter integrity; hence, gray matter loss may present a risk factor for poor response to deep brain stimulation and may be considered when making decision regarding clinical practice.

Levodopa responsiveness and white matter alterations in Parkinson's disease: A DTI-based study and brain network analysis: A cross-sectional study

BACKGROUND

Patients with Parkinson's disease (PD) present various responsiveness to levodopa, but the cause of such differences in levodopa responsiveness is unclear. Previous studies related the damage of brain white matter (WM) to levodopa responsiveness in PD patients, but no study investigated the relationship between the structural brain network change in PD patients and their levodopa responsiveness.

METHODS

PD patients were recruited and evaluated using the Unified Parkinson's Disease Rating Scale (UPDRS). Each patient received a diffusion tensor imaging (DTI) scan and an acute levodopa challenge test. The improvement rate of UPDRS-III was calculated. PD patients were grouped into irresponsive group (improvement rate < 30%) and responsive group (improvement rate ≥ 30%). Tract-based spatial statistics (TBSS), deterministic tracing (DT), region of interest (ROI) analysis, and automatic fiber identification (AFQ) analyses were performed. The structural brain network was also constructed and the topological parameters were calculated.

RESULTS

Fifty-four PD patients were included. TBSS identified significant differences in fractional anisotropy (FA) values in the corpus callosum and other regions of the brain. DT and ROI analysis of the corpus callosum found a significant difference in FA between the two groups. Graph theory analysis showed statistical differences in global efficiency, local efficiency, and characteristic path length.

CONCLUSION

PD patients with poor responsiveness to levodopa had WM damage in multiple brain areas, especially the corpus callosum, which might cause disruption of information integration of the structural brain network.

Levodopa responsiveness in Parkinson's disease: harnessing real-life experience with machine-learning analysis

Responsiveness to levodopa varies greatly among patients with Parkinson's disease (PD). The factors that affect it are ill defined. The aim of the study was to identify factors predictive of long-term response to levodopa. The medical records of 296 patients with PD (mean age of onset, 62.2 ± 9.7 years) were screened for demographics, previous treatments, and clinical phenotypes. All patients were assessed with the Unified PD Rating Scale (UPDRS)-III before and 3 months after levodopa initiation. Regression and machine-learning analyses were used to determine factors that are associated with levodopa responsiveness and might identify patients who will benefit from treatment. The UPDRS-III score improved by ≥ 30% (good response) in 128 patients (43%). On regression analysis, female gender, young age at onset, and early use of dopamine agonists predicted a good response. Time to initiation of levodopa treatment had no effect on responsiveness except in patients older than 72 years, who were less responsive. Machine-learning analysis validated these factors and added several others: symptoms of rigidity and bradykinesia, disease onset in the legs and on the left side, and fewer white vascular ischemic changes, comorbidities, and pre-non-motor symptoms. The main determinants of variations in levodopa responsiveness are gender, age, and clinical phenotype. Early use of dopamine agonists does not hamper levodopa responsiveness. In addition to validating the regression analysis results, machine-learning methods helped to determine the specific clinical phenotype of patients who may benefit from levodopa in terms of comorbidities and pre-motor and non-motor symptoms.

Can Dopamine Responsiveness Be Predicted in Parkinson's Disease Without an Acute Administration Test?

BACKGROUND

Dopamine responsiveness (dopa-sensitivity) is an important parameter in the management of patients with Parkinson's disease (PD). For quantification of this parameter, patients undergo a challenge test with acute Levodopa administration after drug withdrawal, which may lead to patient discomfort and use of significant resources.

OBJECTIVE

Our objective was to develop a predictive model combining clinical scores and imaging.

METHODS

350 patients, recruited by 13 specialist French centers and considered for deep brain stimulation, underwent an acute L-dopa challenge (dopa-sensitivity > 30%), full assessment, and MRI investigations, including T1w and R2* images. Data were randomly divided into a learning base from 10 centers and data from the remaining centers for testing. A machine selection approach was applied to choose the optimal variables and these were then used in regression modeling. Complexity of the modelling was incremental, while the first model considered only clinical variables, the subsequent included imaging features. The performances were evaluated by comparing the estimated values and actual valuesResults:Whatever the model, the variables age, sex, disease duration, and motor scores were selected as contributors. The first model used them and the coefficients of determination (R2) was 0.60 for the testing set and 0.69 in the learning set (p < 0.001). The models that added imaging features enhanced the performances: with T1w (R2 = 0.65 and 0.76, p < 0.001) and with R2* (R2 = 0.60 and 0.72, p < 0.001).

CONCLUSION

These results suggest that modeling is potentially a simple way to estimate dopa-sensitivity, but requires confirmation in a larger population, including patients with dopa-sensitivity < 30.

Can Levodopa Challenge Testing Predict the Effect of Deep Brain Stimulation? One-Year Outcomes in a Chinese Cohort

Objective: Our study examined whether levodopa challenge test (LCT) results could predict quality of life (QoL) outcomes after surgery to implant subthalamic nucleus deep brain stimulation (STN-DBS) electrodes to treat advanced Parkinson’s disease (PD).

Methods: Forty patients with STN-DBS underwent a follow-up 1 year after implantation surgery to analyze the correlation between preoperative levodopa impact test results and postoperative Unified Parkinson’s Disease Rating Scale (UPDRS) III motor score, postoperative PD Questionnaire-39 (PDQ-39) score, and PDQ-39 improvement.

Results: Improvements in QoL were associated with several preoperative characteristics including preoperative UPDRS-III tremor, UPDRS-III tremor (off-60) (p = 0.049), UPDRS-III tremor (off-120) (p = 0.012), Mini-Mental State Examination (p = 0.012), and PDQ-39 (p = 0.012) before surgery. Multiple linear regression model using preoperative MMSE [odds ratio (OR) = 0.342, 95% confidence interval (CI) = 0.051–2.297], preoperative UPDRS-III tremor (OR = 2.099, 95% CI = 0.585–7.535), UPDRS-III tremor (off-60) [OR = 1.316, 95% CI = 0.804–2.154, UPDRS-III tremor (off-120) OR = 0.913, 95% CI = 0.691–1.207], correctly classified 88.5% of patients.

Conclusion: Levodopa challenge test results cannot predict the effect of DBS. However, the test can be incorporated into a regression prediction model to the quality of life of PD patients after DBS with other preoperative factors.

How much time is needed in clinical practice to reach a diagnosis of clinically established Parkinson's disease?

INTRODUCTION

The implementation of accepted clinical diagnostic criteria has improved the accuracy of a clinical diagnosis of Parkinson's disease (PD). Time frames of 3-10 years have been empirically proposed to reach a diagnosis of clinically established PD.

METHODS

We explored the time to a Final Clinical Diagnosis (FCD) and the factors that predict faster diagnoses in patients presenting with parkinsonism and/or tremor between 2009 and 2015 at our tertiary center. All patients underwent a standardized workout process to reach a FCD, which included an acute levodopa challenge (LDC) after the first visit.

RESULTS

Among the 326 patients included, 215 (66%) received a FCD within the first six months after the LDC. A FCD was reached in 95% and 100% of patients in 33 and 108 months, respectively. PD was the FCD in 196 patients (60.1%). The FCD was reached faster in patients with a positive response to levodopa and when the FCD was PD.

CONCLUSION

The time needed to reach a final diagnosis in the clinical setting was 2.75 years in 95% of patients presenting initially with parkinsonism and/or tremor. Patients with positive responses to levodopa at the LDC, benefited from shorter delays until the FCD.

Predicting Long-Term Outcome of Patients of Early Parkinsonism with Acute Levodopa Challenge Test

Objectives

The aim of this study was to evaluate the sensitivity and specificity of various outcomes of acute levodopa challenge test (ALCT) namely improvement of motor function, development of dyskinesia and intolerance; to predict the diagnosis of idiopathic Parkinson's disease (IPD) or Parkinson-plus syndrome; to predict levodopa responsiveness and levodopa-induced dyskinesia (LID) during long-term therapy.

Methods

ALCT was performed on 89 patients with parkinsonism of <2 years and were followed up for 18 months. Improvement of UPDRSm by ≥30% was considered positive.

Results

The test was positive in 37 (43.5%) and negative in 48 (56.5%) of 85 patients completing it. Of the 75 patients completing 18 months' follow-up 34 (45.3%) were diagnosed as IPD. A positive ALCT predicted a clinical diagnosis of IPD with sensitivity and specificity of 97.4% and 70.7% respectively. The predictive value of ALCT for long-term levodopa responsiveness was less than predicting a diagnosis of IPD. While appearance of dyskinesia during ALCT had a low predictive value for future LID (sensitivity 14.3%), it had high predictive value for a diagnosis of multisystem atrophy (MSA) (91% specificity and 37.5% sensitivity). The appearance of symptoms of levodopa intolerance (SLI) during ALCT could predict a clinical diagnosis of MSA with high specificity (95.5%) and moderate sensitivity (50%).

Conclusion

Levodopa responsiveness during ALCT was useful in predicting a diagnosis of IPD but not long-term response to levodopa. The development of dyskinesia during ALCT could not correctly predict LID, but could predict a diagnosis of MSA. The appearance of SLI during ALCT could also predict MSA correctly.

Levodopa responsiveness in Parkinson's disease patients and white matter alterations in diffusion tensor imaging: a cross-sectional tract-based spatial statistics study

This study aimed to investigate the relationship between levodopa responsiveness and white matter alterations in Parkinson's disease patients using diffusion tensor imaging (DTI). Twenty-six recruited Parkinson's disease patients were evaluated using the Mini-Mental State Examination, Hoehn and Yahr scale (H&Y) and Unified Parkinson's Disease Rating Scale (UPDRS). Each patient underwent a DTI scan and an acute levodopa challenge test. The improvement rate of UPDRS-III was calculated, Parkinson's disease patients were grouped into a responsive group (improvement rate ≥30%) and a nonresponsive group (improvement rate <30%). The differences in fractional anisotropy, mean diffusivity, axial diffusivity and radial diffusivity between the two groups were measured using tract-based spatial statistics. There was no difference in demographic features or baseline evaluations between groups. The UPDRS-III score after the challenge was higher in the nonresponsive group than that in the responsive group. Compared to the responsive group, patients in the nonresponsive group exhibited decreased fractional anisotropy in the corpus callosum; cingulum; left corona radiata; left internal capsule; left middle frontal gyrus; left superior longitudinal fasciculus and right somatosensory cortex. Mean diffusivity and radial diffusivity were increased in wide-ranging areas in the nonresponsive group. No difference was observed in axial diffusivity. White matter alterations in the abovementioned areas may affect the function of the dopaminergic network and thus may be associated with the levodopa response in Parkinson's disease patients. Further studies are needed to analyze the specific mechanism and pathological changes underlying these effects.

Clinical Outcome and Striatal Dopaminergic Function After Shunt Surgery in Patients With Idiopathic Normal Pressure Hydrocephalus

OBJECTIVE

To determine changes in clinical features and striatal dopamine reuptake transporter (DAT) density after shunt surgery in patients with idiopathic normal pressure hydrocephalus (iNPH).

METHODS

Participants with probable iNPH were assessed at baseline by means of clinical rating scales, brain MRI, and SPECT with [¹²³I]-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane (FP-CIT). Levodopa responsiveness was also evaluated. Patients who did or did not undergo lumboperitoneal shunt were clinically followed up and repeated SPECT after 2 years.

RESULTS

We enrolled 115 patients with iNPH. Of 102 patients without significant levodopa response and no signs of atypical parkinsonism, 92 underwent FP-CIT SPECT (58 also at follow-up) and 59 underwent surgery. We identified a disequilibrium subtype (phenotype 1) and a locomotor subtype (phenotype 2) of higher-level gait disorder. Gait impairment correlated with caudate DAT density in both phenotypes, whereas parkinsonian signs correlated with putamen and caudate DAT binding in patients with phenotype 2, who showed more severe symptoms and lower striatal DAT density. Gait and caudate DAT binding improved in both phenotypes after surgery (p < 0.01). Parkinsonism and putamen DAT density improved in shunted patients with phenotype 2 (p < 0.001). Conversely, gait, parkinsonian signs, and striatal DAT binding worsened in patients who declined surgery (p < 0.01).

CONCLUSIONS

This prospective interventional study highlights the pathophysiologic relevance of striatal dopaminergic dysfunction in the motor phenotypic expression of iNPH. Absence of levodopa responsiveness, shunt-responsive parkinsonism, and postsurgery improvement of striatal DAT density are findings that corroborate the notion of a reversible striatal dysfunction in a subset of patients with iNPH.

Quantitative Assessment of Motor Response to a Low Subacute Levodopa Dose in the Differential Diagnosis of Parkinsonisms at Disease Onset: Data from the BoProPark Cohort

Background:

Differential diagnosis between Parkinson’s disease (PD) and atypical parkinsonisms (APs) may be difficult at disease onset. The response to levodopa (LD) is a key supportive feature but its definition is largely empirical. Studies evaluating this issue by quantitative tests are scanty.

Objective:

We aimed to assess the utility of a subacute low LD dose kinetic-dynamic test in the differential diagnosis between PD and APs. It was applied at the baseline of a prospective follow-up in patients with parkinsonian signs within three years of disease motor onset (“BoProPark” cohort) and eventually diagnosed as PD or APs according to consensus criteria.

Methods:

Patients under at least 3-month LD therapy received a first morning fasting dose of LD/benserazide or carbidopa (100/25 mg) and underwent simultaneous serial assessments of plasma LD concentration and alternate finger tapping frequency up to 3 h. The main outcome was the extent of LD motor response, calculated by the area under the 3 h tapping effect–time curve (AUC_ETap). A receiver operating characteristic (ROC) curve analysis was performed to establish the optimal AUC_ETap cut-off to differentiate PD and APs.

Results:

The first 100 consecutive “BoProPark” patients were analyzed. Forty-seven patients were classified as possible, 37 as probable PD and 16 as APs. AUC_ETap medians were similar in the PD subgroups but reduced to a third in APs (p < 0.001). The optimal AUC_ETap cut-off value was >2186 [(tap/min) x min], with a sensitivity of 92% and a specificity of 75%. Accuracy of the test was 0.85 (95% CI 0.74–0.95), p < 0.0001.

Conclusion:

The estimation of 3 h AUC_ETap after a subacute low LD dose proved a reliable, objective tool to assess LD motor response in our cohort of patients. AUC_ETap value rounded to ≥2200 supports PD diagnosis, while lower values may alert to AP diagnoses.

Gait Analysis of Old Individuals with Mild Parkinsonian Signs and Those Individuals' Gait Performance Benefits Little from Levodopa

Background and Purpose

Gait analysis and the effects of levodopa on the gait characteristics in Mild parkinsonian signs (MPS) are rarely published. The present research aimed to (1) analyze the gait characteristics in MPS; (2) explore the effects of levodopa on the gait performance of MPS.

Methods

We enrolled 22 inpatients with MPS and 20 healthy control subjects (HC) from Nanjing Brain Hospital. The Unified Parkinson’s Disease Rating Scale was used to evaluate motor symptoms. Acute levodopa challenge test was performed to explore the effects of levodopa on the gait performance of MPS. The instrumented stand and walk test was conducted for each participant and the JiBuEn gait analysis system was used to collect gait data.

Results

For spatiotemporal parameters: Compared with HC, the state before taking levodopa/benserazide in MPS group (meds-off) demonstrated a decrease in stride length (SL) (p≤0.001), an increase in SL variability (p≤0.001), and swing phase time variability (p=0.016). Compared with meds-off, the state after 1 hour of taking levodopa/benserazide in MPS group (meds-on) exhibited an increase in SL (p≤0.001), a decrease in SL variability (p≤0.001). For kinematic parameters: Compared with HC, meds-off demonstrated a decrease in heel strike angle (p=0.008), range of motion (ROM) of knee joint (p=0.011) and ROM of hip joint (p=0.007). Compared with meds-off, meds-on exhibited an increase in HS (p≤0.001). Bradykinesia and rigidity scores were significantly correlated with gait parameters.

Conclusion

Although the clinical symptoms of the MPS group are mild, their gait damage is obvious and they exhibited a decreased SL and joints movement, and a more variable gait pattern. Levodopa had little effect on the gait performance of those individuals.

Deep Brain Stimulation Selection Criteria for Parkinson's Disease: Time to Go beyond CAPSIT-PD

Despite being introduced in clinical practice more than 20 years ago, selection criteria for deep brain stimulation (DBS) in Parkinson's disease (PD) rely on a document published in 1999 called 'Core Assessment Program for Surgical Interventional Therapies in Parkinson's Disease'. These criteria are useful in supporting the selection of candidates. However, they are both restrictive and out-of-date, because the knowledge on PD progression and phenotyping has massively evolved. Advances in understanding the heterogeneity of PD presentation, courses, phenotypes, and genotypes, render a better identification of good DBS outcome predictors a research priority. Additionally, DBS invasiveness, cost, and the possibility of serious adverse events make it mandatory to predict as accurately as possible the clinical outcome when informing the patients about their suitability for surgery. In this viewpoint, we analyzed the pre-surgical assessment according to the following topics: early versus delayed DBS; the evolution of the levodopa challenge test; and the relevance of axial symptoms; patient-centered outcome measures; non-motor symptoms; and genetics. Based on the literature, we encourage rethinking of the selection process for DBS in PD, which should move toward a broad clinical and instrumental assessment of non-motor symptoms, quantitative measurement of gait, posture, and balance, and in-depth genotypic and phenotypic characterization.

Striatal Dopamine Deficit and Motor Impairment in Idiopathic Normal Pressure Hydrocephalus

BACKGROUND

Idiopathic normal pressure hydrocephalus can present with parkinsonism. However, abnormalities of the striatal dopamine reuptake transporter are unclear.

OBJECTIVES

To explore presence and features of striatal dopaminergic deficit in subjects with idiopathic normal pressure hydrocephalus as compared to Parkinson's disease (PD) patients and healthy controls.

METHODS

We investigated 50 subjects with idiopathic normal pressure hydrocephalus, 25 with PD, and 40 healthy controls. All participants underwent [¹²³ I]-N-ω-fluoropropyl-2β-carbomethoxy-3β-(4-iodophenyl)nortropane and single-photon emission computed tomography to quantify the striatal dopamine reuptake transporter binding. All subjects with idiopathic normal pressure hydrocephalus underwent a levodopa (l-dopa) challenge test and magnetic resonance imaging to evaluate ventriculomegaly and white matter changes. Gait, cognition, balance, and continence were assessed with the Idiopathic Normal Pressure Hydrocephalus Rating Scale, and parkinsonism with the motor section of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale. All patients completed a 2-year follow-up.

RESULTS

A total of 62% of patients with idiopathic normal pressure hydrocephalus featured a reduced striatal dopamine reuptake transporter binding, which correlated with the severity of parkinsonism but not with features of ventriculomegaly or white matter changes. Unlike PD, this dopaminergic deficit in idiopathic normal pressure hydrocephalus was more symmetric and prominent in the caudate nucleus.

CONCLUSIONS

Subjects with idiopathic normal pressure hydrocephalus can present a reduction of striatal dopamine reuptake transporter binding, which is consistent with the severity of parkinsonism and qualitatively differs from that found in PD patients. Longitudinal interventional studies are needed to prove a role for striatal dopamine reuptake transporter deficit in the pathophysiology of idiopathic normal pressure hydrocephalus. © 2020 International Parkinson and Movement Disorder Society.

Intraoperative Neurophysiologic Assessment in Deep Brain Stimulation Surgery and its Impact on Lead Placement

OBJECTIVES

 While the efficacy of deep brain stimulation (DBS) to treat various neurological disorders is undisputed, the surgical methods differ widely and the importance of intraoperative microelectrode recording (MER) or macrostimulation (MS) remains controversially debated. The objective of this study is to evaluate the impact of MER and MS on intraoperative lead placement.

PATIENTS AND METHODS

 We included 101 patients who underwent awake bilateral implantation of electrodes in the subthalamic nucleus with MER and MS for Parkinson's disease from 2009 to 2017 in a retrospective observational study. We analyzed intraoperative motor outcomes between anatomically planned stimulation point (PSP) and definite stimulation point (DSP), lead adjustments and Unified Parkinson's Disease Rating Scale Item III (UPDRS-III), levodopa equivalent daily dose (LEDD), and adverse events (AE) after 6 months.

RESULTS

 We adjusted 65/202 leads in 47/101 patients. In adjusted leads, MS results improved significantly when comparing PSP and DSP (p < 0.001), resulting in a number needed to treat of 9.6. After DBS, UPDRS-III and LEDD improved significantly after 6 months in adjusted and nonadjusted patients (p < 0.001). In 87% of leads, the active contact at 6 months still covered the optimal stimulation point during surgery. In total, 15 AE occurred.

CONCLUSION

 MER and MS have a relevant impact on the intraoperative decision of final lead placement and prevent from a substantial rate of poor stimulation outcome. The optimal stimulation points during surgery and chronic stimulation strongly overlap. Follow-up UPDRS-III results, LEDD reductions, and DBS-related AE correspond well to previously published data.

Parkinson's Disease: Available Clinical and Promising Omics Tests for Diagnostics, Disease Risk Assessment, and Pharmacotherapy Personalization

Parkinson's disease is the second most frequent neurodegenerative disease, representing a significant medical and socio-economic problem. Modern medicine still has no answer to the question of why Parkinson's disease develops and whether it is possible to develop an effective system of prevention. Therefore, active work is currently underway to find ways to assess the risks of the disease, as well as a means to extend the life of patients and improve its quality. Modern studies aim to create a method of assessing the risk of occurrence of Parkinson's disease (PD), to search for the specific ways of correction of biochemical disorders occurring in the prodromal stage of Parkinson's disease, and to personalize approaches to antiparkinsonian pharmacotherapy. In this review, we summarized all available clinically approved tests and techniques for PD diagnostics. Then, we reviewed major improvements and recent advancements in genomics, transcriptomics, and proteomics studies and application of metabolomics in PD research, and discussed the major metabolomics findings for diagnostics and therapy of the disease.

Levodopa challenge test: indications, protocol, and guide

A drug challenge test in Parkinson's disease, such as the levodopa challenge test (LCT), is an easy and generally safe procedure, which has been used by clinicians for various indications. The results of the test have significant implications in the management of patients, from preoperative evaluation for deep brain stimulation to providing the basis for medication adjustments to address motor or non-motor fluctuations and dyskinesias. This paper reviews the different indications and protocols commonly used in an acute LCT. Potential complications of the procedure and an overview of levodopa responsiveness and unresponsiveness are also discussed.

Orofacial Strength and Voice Quality as Outcome of Levodopa Challenge Test in Parkinson Disease

OBJECTIVE

To assess the usefulness of orofacial strength and voice quality as assessment of response to levodopa challenge test (LCT) used in the diagnosis of early idiopathic Parkinson disease (IPD).

STUDY DESIGN

Controlled Prospective Study.

METHODS

From January 2014 to April 2019, patients with early IPD and healthy individuals were recruited and evaluated for clinical findings (Hoehn and Yahr scale; Unified Parkinson's Disease Rating Scale); Voice Handicap Index (VHI); grade of dysphonia, roughness, breathiness, asthenia, and strain and instability (GRBASI); maximal phonation time; phonation quotient; acoustic parameters; and orofacial muscle strength Oral Performance Instrument (IOPI; IOPI Medical, Woodinville, WA, USA) t) at baseline and 45 minutes after the levodopa intake (LCT).

RESULTS

A total of 32 IPD patients and 20 healthy individuals completed the study. Healthy individuals exhibited better VHI, grade of dysphonia, breathiness, asthenia, strain, instability, and acoustic measurements (noise-related, tremor, F0 short- and mid-term and intensity short-term parameters) than healthy subjects. The mean values of muscle strength of lips, cheeks, fundamental frequency (F0), highest F0, and shimmer significantly improved from pre- to post-LCT in IPD patients. Healthy individuals did not exhibit significant changes of orofacial strength and voice quality assessment from pre- to post-LCT. Significant associations were found between clinical, orofacial strength, and some aerodynamic and acoustic measurements.

CONCLUSION

Orofacial strength and acoustic voice quality measurements may be used as objective outcomes of the LCT responsiveness in patients with early IPD.

LEVEL OF EVIDENCE

3A. Laryngoscope, 2020.

Prediction of the Levodopa Challenge Test in Parkinson's Disease Using Data from a Wrist-Worn Sensor

The response to levodopa (LR) is important for managing Parkinson’s Disease and is measured with clinical scales prior to (OFF) and after (ON) levodopa. The aim of this study was to ascertain whether an ambulatory wearable device could predict the LR from the response to the first morning dose. The ON and OFF scores were sorted into six categories of severity so that separating Parkinson’s Kinetigraph (PKG) features corresponding to the ON and OFF scores became a multi-class classification problem according to whether they fell below or above the threshold for each class. Candidate features were extracted from the PKG data and matched to the class labels. Several linear and non-linear candidate statistical models were examined and compared to classify the six categories of severity. The resulting model predicted a clinically significant LR with an area under the receiver operator curve of 0.92. This study shows that ambulatory data could be used to identify a clinically significant response to levodopa. This study has also identified practical steps that would enhance the reliability of this test in future studies.

The Parkinson's Disease Composite Scale Is Adequately Responsive to Acute Levodopa Challenge

Background

The Parkinson's Disease Composite Scale (PDCS) is a recently developed easy-to-use tool enabling a timely but comprehensive assessment of Parkinson's disease (PD)-related symptoms. Although the PDCS has been extensively validated, its responsiveness to acute levodopa challenge has not been demonstrated yet.

Objective

To investigate the correlation between changes in the motor examination part of the Movement Disorder Society-sponsored Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and the PDCS motor scores during acute levodopa challenge and calculate a cutoff range on the PDCS indicating clinically relevant improvement.

Methods

A consecutive series of 100 patients with parkinsonism were assessed using the motor examination sections of the MDS-UPDRS and the PDCS at least 12 hours after the last levodopa dose and after the administration of a single dose of a suprathreshold immediate formulation of levodopa/benserazide reaching the "best ON." Results. There was a high correlation between changes in the MDS-UPDRS and the PDCS motor scores (Spearman's rho = 0.73, p < 0.001). Receiver operating characteristic analysis revealed that a 14.6%-18.5% improvement in the PDCS motor scores corresponds to a 20-30% improvement in the MDS-UPDRS motor examination.

Conclusions

The PDCS can reliably and adequately respond to an acute levodopa challenge. Any improvements in PDCS motor scores exceeding the 14.6-18.5% threshold could represent a clinically relevant response to levodopa.

Diagnostic biomarkers for Parkinson's disease at a glance: where are we?

Parkinson's disease (PD) is a neurodegenerative disorder whose aetiology remains unclear: degeneration involves several neurotransmission systems, resulting in a heterogeneous disease characterized by motor and non-motor symptoms. PD causes progressive disability that responds only to symptomatic therapies. Future advances include neuroprotective strategies for use in at-risk populations before the clinical onset of disease, hence the continuing need to identify reliable biomarkers that can facilitate the clinical diagnosis of PD. In this evaluative review, we summarize information on potential diagnostic biomarkers for use in the clinical and preclinical stages of PD.

Subjective Perceived Motor Improvement after Acute Levodopa Challenge in Parkinson's Disease

BACKGROUND

Previous studies found a poor association between parkinsonian patient's reported subjective improvement after commencing dopaminergic treatment and improvements in objective measures of motor impairment by clinician.

OBJECTIVE

To compare PD patient's subjective perceived motor improvement after acute levodopa challenge test with objective motor improvement assessed by the clinician using the UPDRS part III. To analyze clinical characteristics, i.e. age, disease duration, cognitive performance or severity of axial features, that may have influenced patient's perception.

METHODS

Fifty-seven consecutive PD patients (23 women, 34 men; mean age, 63.4±7.7 years) (Hoehn and Yahr off score, 2.5±0.7; mean disease duration, 11.4±4.1 years) completed the acute levodopa challenge. The percentage of improvement in motor disability, i.e. objective motor improvement, was determined with respect to the off-drug condition.

RESULTS

Bland & Altman visual analysis reveals a high degree of correlation between objective and subjective perceived motor improvement. Both the axial sub-scores in the off- and on-state (respectively, P = 0.006 and P = 0.024) and the presence of peak-dose dyskinesia (P = 0.043) significantly influence the difference between objective and subjective perceived motor improvement.

CONCLUSIONS

This is the first study reporting on how PD patients assessed their motor improvement after acute levodopa challenge. These findings suggest a strong correlation between objective motor improvement assessed by the clinician using the UPDRS part III and subjective perceived motor improvement reported by the patient.

[Deep brain stimulation in parkinsonian patients with dopa intolerance]

Deep brain stimulation (DBS) is at present, a useful treatment for patients with advanced Parkinson's disease and motor complications. The crucial step toward consistent DBS outcomes remains careful patient selection; several conditions must be fulfilled including excellent levo dopa response. We report two cases of early onset Parkinson's disease with severe intolerance to levo dopa but excellent and sustained response to DBS. DBS can be a useful alternative for parkinsonian patients with severe intolerance to levo dopa, provided a positive acute response to levo dopa or apomorphine is obtained.

Diagnostic Value of Combined Acute Levodopa Challenge and Olfactory Testing to Predict Parkinson's Disease

BACKGROUND

The diagnosis of Parkinson's disease (PD) can be challenging early in the disease course, when motor features are subtle. The objective of this study was to explore the diagnostic value of combining acute levodopa challenge and olfactory testing to predict PD.

METHODS

Data from 210 patients with a recent onset of parkinsonism who had at least 2 years of follow-up and underwent acute levodopa challenge for the clinical prediction of long-term dopaminergic response and had olfactory testing with Sniffin' Sticks Test were evaluated. Single and combined diagnostic measures were analyzed.

RESULTS

After 2 years of follow-up, a PD diagnosis was confirmed in 157 patients who fulfilled United Kingdom Parkinson's Disease Society Brain Bank criteria and was ruled out in 53. Sensitivity and specificity of acute levodopa challenge to predict PD diagnosis were 0.71 and 0.94, respectively. Sensitivity and specificity of olfactory tests were calculated according to the total olfactory score for hyposmia (0.61 and 0.77 respectively), the hyposmia identification subscore (0.63 and 0.74, respectively), and the anosmia score (0.40 and 0.85, respectively). The best combination identified was response to acute levodopa challenge together with hyposmia according to the total olfactory score (sensitivity, 0.90; specificity, 0.74; positive predictive value, 0.91; negative predictive value, 0.72; accuracy, 0.86).

CONCLUSION

The combination of response to acute levodopa challenge with hyposmia according to the total olfactory score improved sensitivity for the early diagnosis of PD.

Acute Levodopa Challenge Test in Patients with de novo Parkinson's Disease: Data from the DeNoPa Cohort

Background

The precise clinical diagnosis of Parkinson's disease (PD) can be difficult in the early stages. Diagnostic criteria include the response of key motor features to levodopa as a supportive prospective criterion. Data are sparse on the diagnostic value of the acute levodopa challenge test (LDCT) in patients with de novo PD. The objective of this study was to validate the LDCT as a tool in the early clinical diagnosis of PD.

Methods

We performed the standardized LDCT with 250 mg levodopa in the prospective longitudinal cohort study "DeNoPa," comprising 159 patients with de novo PD, and carried out longitudinal clinical follow-up for 24 months. Motor assessments at baseline using the motor part (part III) of the Unified Parkinson's Disease Rating Scale before and 1 hr after drug administration were documented. The optimal cutoff score on the LDCT was calculated using the Youden index.

Results

Clinical reassessment of 144 patients who returned for follow-up confirmed the diagnosis of PD in 120 patients (83%). In 24 patients (17%), the initial diagnoses were revised and classified as other neurologic disorders. The optimal cutoff at 33% improvement of motor symptoms on the part 3 of the Unified Parkinson's Disease Rating Scale during the LDCT reached a sensitivity of 70% a specificity of 71%. The positive and negative predictive values were 92% and 32%, respectively. Sensitivity (91%), specificity (79%), and positive/negative (96%/63%) predictive values improved with the addition of further clinical information (urinary incontinence, fainting, asymmetric tremor, and amount of further drug-intake).

Conclusions

The LDCT is a reliable tool in the early diagnosis of PD. The accuracy of this test can be further improved by additional, easy-to-acquire clinical information provided by patients. © 2017 International Parkinson and Movement Disorder Society.

Frailty phenotype and the role of levodopa challenge test in geriatric inpatients with mild parkinsonian signs

Deficiency in dopaminergic system function may be one of the hypothetical reasons of the frailty syndrome but its role still remains unclear. The aim of our study was to assess the frailty phenotype prevalence in geriatric inpatients with mild parkinsonian signs (MPS) and to investigate levodopa test in the frail patients with MPS. We examined 118 participants: 90 with MPS and 28 in control group (without MPS). The frailty syndrome presence was evaluated by the Fried criteria. Deficiency in dopaminergic system function was assessed by one of the modifications of an acute levodopa challenge test (LCT): in MPS group every patient was examined by performing Up and Go Test and also Step Test before and 3 h after taking 125 mg of Madopar (levodopa + benserazide). Sixty-nine study subjects (58%) met criteria for frailty. Fifty-five participants in MPS group (61.1% of MPS group) and fourteen (50%) in control group. All of the patients that scored positive in walk speed criterion of frailty were frail. When all MPS patients were considered, the number of components scored positive for frailty was directly related to the walk speed (r = -0.70, p < 0.0001). In MPS group LCT scores were significantly higher for frailty patients compared to non-frailty (p = 0.0027). When all MPS patients were considered, the number of components scored positive for frailty was directly related LCT score (r = 0.37, p = 0.0004). There was a relationship between LCT and walk speed (r = -0.31, p = 0.0032). Our observations provide new information about the relationship between frailty and MPS, suggest the need for increased awareness of frailty in MPS patients and conversely. Our study provides data for a discussion on pathophysiological background of the frailty syndrome (FS), emphasizing the theories of the important impact of dopaminergic system deficit and encourages further research on the role of LCT in measuring it.

Homovanillic acid in CSF of mild stage Parkinson's disease patients correlates with motor impairment

In Parkinson's disease (PD), several efforts have been spent in order to find biochemical parameters able to identify the progression of the pathological processes at the basis of the disease. It is already known that advanced PD patients manifesting dyskinesia are featured by the high homovanillic acid (HVA)/dopamine (DA) ratio, suggesting the increased turnover of DA in these patients. Less clear is whether similar changes affect mild and moderate stages of the disease (between 1 and 2.5 of Hoehn & Yahr -H&Y- stage). Hence, here we tested whether cerebrospinal fluid (CSF) concentrations of DA and its major metabolites, either 3,4-dihydroxyphenylacetic acid (DOPAC) or HVA, correlate with motor performance in mild and moderate PD patients. CSF samples were collected after 2 days of anti-PD drugs washout, via lumbar puncture (LP) performed 130 min following administration of oral levodopa (LD) dose (200 mg). LP timing was determined in light of our previous tests clarifying that 2 h after oral LD administration CSF DA concentration reaches a plateau, which was un-respective of PD stage or duration. DA, DOPAC and HVA were assayed by high performance liquid chromatography in a group of 19 patients, distributed in two groups on the basis of the H&Y stage with a cut-off of 1.5. In these PD patients, HVA was correlated with DOPAC (R = 0,56, p < 0,01) and both HVA and DOPAC CSF levels increased in parallel with the motor impairment. More importantly, HVA correlated with motor impairment measured by the Unified Parkinson's Disease Score -III (UPDRS) (R = 0.61; p < 0.0001). The present findings showed the early alteration of the DA pre-synaptic machinery, as documented by the progressive increase of CSF HVA concentrations, which also correlated with PD motor impairment. Therefore, we suggest the potential use of measuring the CSF HVA level as a possible biomarker of PD stage changes in order to monitor the effectiveness of PD-modifying pharmacological therapies.

Facial tremors in patients with and without parkinsonism

Facial (lip and jaw) tremors can be an early sign of Parkinson's disease (PD), essential tremor and other parkinsonisms. Its response to acute dopaminergic therapy and further predictive clinical diagnosis has not been previously addressed. The aim of this study was to evaluate facial tremors response to acute dopaminergic therapy and further predictive value for clinical diagnosis. A retrospective review of medical records from patients with recent onset of facial tremor, with or without parkinsonism, submitted to acute levodopa challenge for clinical prediction of sustained long-term dopaminergic response was conducted. Twenty-eight out of 559 patients (5 %) had facial tremors, which responded to levodopa in 46 % of patients. Facial tremors response to acute levodopa challenge showed 92 % sensitivity and 93 % specificity to predict a final PD diagnosis. In PD patients, facial tremor magnitude of response to levodopa was not different from that of hand rest tremor (p = 0.8). Facial tremors, although infrequent, can be an early sign of PD. Positive response to acute levodopa challenge predicts long-term PD diagnosis.

Effect of Age and Disease Duration on the Levodopa Response in Patients with Advanced Parkinson's Disease for Deep Brain Stimulation of the Subthalamic Nucleus

Background

Deep brain stimulation (DBS) has become a preferred option for the treatment of motor symptoms in patients with advanced Parkinson’s disease (PD). A good levodopa response (LR) is considered the most important criterion in determining the suitability of a patient for DBS. However, the effect of age and disease duration (DD) on the LR is still a subject of discussion.

Objective

Here, we investigated the effect of age and DD on the preoperative LR in PD patients to be selected for DBS.

Methods

From August 2011 to May 2015, 54 consecutive patients (29 men and 25 women) with advanced PD were evaluated for DBS of the STN and included in this retrospective study.

Results

Thirty-seven patients were found suitable for DBS of the STN and 29 of them underwent bilateral surgery. We found no significant correlation between DD and the LR. However, there was a significant negative correlation between the patients’ age and the LR.

Conclusion

The results indicate that the patients’ age, rather than DD, has a negative effect on the LR. The study, therefore, indicates that PD patients with an advanced age and with a poor LR are not good candidates for DBS of the STN.

Motor features in Parkinson's disease with normal olfactory function

BACKGROUND

Normosmic Parkinson's disease (PD) might be a unique clinical phenotype with a more benign course when compared with hyposmic PD.

OBJECTIVE

The objective of this study was to evaluate motor features and the acute levodopa response according to olfactory function.

METHODS

A total of 169 de novo PD patients that underwent olfactory testing and acute levodopa challenge for clinical prediction of sustained long-term dopaminergic response were evaluated.

RESULTS

The overall frequency of normosmia was 33%. Normosmic PD patients scored nonsignificantly different to hyposmic/anosmic patients on motor scale and on degree of improvement with levodopa. Motor scores at follow-up were comparable among groups.

CONCLUSIONS

Normal olfactory function is common in early PD and was not associated with a different motor phenotype when compared with PD patients with olfactory dysfunction. © 2016 International Parkinson and Movement Disorder Society.

The BioFIND study: Characteristics of a clinically typical Parkinson's disease biomarker cohort

BACKGROUND

Identifying PD-specific biomarkers in biofluids will greatly aid in diagnosis, monitoring progression, and therapeutic interventions. PD biomarkers have been limited by poor discriminatory power, partly driven by heterogeneity of the disease, variability of collection protocols, and focus on de novo, unmedicated patients. Thus, a platform for biomarker discovery and validation in well-characterized, clinically typical, moderate to advanced PD cohorts is critically needed.

METHODS

BioFIND (Fox Investigation for New Discovery of Biomarkers in Parkinson's Disease) is a cross-sectional, multicenter biomarker study that established a repository of clinical data, blood, DNA, RNA, CSF, saliva, and urine samples from 118 moderate to advanced PD and 88 healthy control subjects. Inclusion criteria were designed to maximize diagnostic specificity by selecting participants with clinically typical PD symptoms, and clinical data and biospecimen collection utilized standardized procedures to minimize variability across sites.

RESULTS

We present the study methodology and data on the cohort's clinical characteristics. Motor scores and biospecimen samples including plasma are available for practically defined off and on states and thus enable testing the effects of PD medications on biomarkers. Other biospecimens are available from off state PD assessments and from controls.

CONCLUSION

Our cohort provides a valuable resource for biomarker discovery and validation in PD. Clinical data and biospecimens, available through The Michael J. Fox Foundation for Parkinson's Research and the National Institute of Neurological Disorders and Stroke, can serve as a platform for discovering biomarkers in clinically typical PD and comparisons across PD's broad and heterogeneous spectrum. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Ultrasound Strain Elastography in Assessment of Muscle Stiffness in Acute Levodopa Challenge Test: A Feasibility Study

To evaluate the feasibility of ultrasound strain elastography in assessing the response of muscle stiffness to the acute levodopa test, we prospectively performed strain elastography on the biceps brachii muscle (BBM) of 18 patients to diagnose Parkinson's disease. BBM and subcutaneous tissue strains (deformations) were produced by external compression with an ultrasound transducer and estimated using 2-D speckle tracking. We used the strain ratio (SR = BBM strain/reference strain) to assess BBM stiffness. The rate of increase in SR [rate = (SR after levodopa-SR before levodopa)/SR before levodopa] was used to assess the muscle stiffness response to levodopa. SR significantly increased after levodopa administration in 11 patients with Parkinson's disease (p = 0.02), whereas it did not in 7 patients with parkinsonian syndrome (from non-Parkinson's causes) (p = 0.14). The area under the receiver operating characteristic curve for the rate of increase in SR in determining Parkinson's disease was 0.96. The rate of increase in SR seems to be feasible in evaluating the effect of levodopa on muscle stiffness in the diagnosis of Parkinson's disease.

Biomarkers in Parkinson’s disease

Parkinson's disease (PD) is a common neurodegenerative disorder that is largely diagnosed and managed clinically. Biomarkers, as indicators of underlying biological processes, offer the potential to identify individuals at risk for PD, screen new therapies, assist in the diagnosis and help optimize management of PD. However, to date, biomarkers, despite their considerable promise, have had limited utility in clinical trials and practice.

Clinical utility of dopamine transporter single photon emission CT (DaT-SPECT) with (123I) ioflupane in diagnosis of parkinsonian syndromes

The diagnosis of movement disorders including Parkinson's disease (PD) and essential tremor is determined through clinical assessment. The difficulty with diagnosis of early PD has been highlighted in several recent clinical trials. Studies have suggested relatively high clinical diagnostic error rates for PD and essential tremor. This review was undertaken to clarify the utility of DaT-SPECT imaging with ((123)I)ioflupane (DaTSCAN or DaTscan or ((123)I)FP-CIT) in assisting practitioners in their clinical decision making by visualising the dopamine transporter in parkinsonian cases. In some patients with suspected parkinsonian syndromes, SPECT imaging with ((123)I)ioflupane is useful to assist in the diagnosis and to help guide prognosis and treatment decisions, including avoiding medications that are unlikely to provide benefit. Clinicians ordering ((123)I)ioflupane SPECT should be aware of its limitations and pitfalls and should order scans when there is diagnostic uncertainty or when the scan will be helpful in clinical decision making.

Levodopa challenge test and (123) I-metaiodobenzylguanidine scintigraphy for diagnosing Parkinson's disease

OBJECTIVES

To explore the possibility of a generally applicable tool for the immediate diagnosis of Parkinson's disease (PD) in its early stage, we compared the sensitivity and specificity of an acute levodopa challenge test with that of (123) I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy.

MATERIALS AND METHODS

A consecutive series of 45 patients with extrapyramidal symptoms were recruited to the acute levodopa challenge and evaluated for improvement by use of the Unified Parkinson's Disease Rating Scale motor scores. Of these patients, 32 of them were also examined by MIBG scintigraphy. The patients were followed up for at least 24 months, and 22 patients were diagnosed as having clinically definite PD.

RESULTS

The sensitivity and specificity of the acute levodopa challenge test to predict clinical diagnosis of PD were 81.8% and 81.8%, respectively, which were better than those obtained by MIBG scintigraphy (62.5% and 62.5%). In both early- and middle-stages of PD, the test gave better sensitivity than MIBG scintigraphy.

CONCLUSIONS

Considering that the well-established and frequently referred clinical diagnostic criteria require longitudinal observation for at least 24 months, the acute levodopa challenge test can be used as an immediate diagnostic tool for PD with sensitivity and specificity comparable to those of MIBG.

Evaluation of the objective posturo-locomotor-manual method in patients with parkinsonian syndromes

Objective methods for quantifying patients' movement capacity would be useful in evaluating progression and interventions in neurodegenerative diseases. The Posturo-Locomotor-Manual (PLM) test is a standardized automated movement test developed to measure hypokinetic movements in patients with Parkinsonism. Our hypotheses were that the PLM movement time (MT) correlates with the Unified Parkinson's disease rating scale (UPDRS III) motor section, and that the components of the PLM test correlate with the corresponding constructed domains of UPDRS III. We also evaluated the coherence between the results of the two assessment methods after a test dose of levodopa (l-DOPA). We assessed motor function using the PLM method and UPDRS III in parallel, in the absence of medication and after administration of 200 mg l-DOPA, in 73 patients with moderate to advanced Parkinsonism: 47 with Parkinson's disease (PD), 17 with multiple system atrophy (MSA), and 9 with progressive supranuclear palsy (PSP). There was a fair correlation between the two assessment tools in the PD patients but not in the MSA or PSP patients. In the full dataset, there was a fair to good correlation between UPDRS III and the PLM MT. At group level, the UPDRS III l-DOPA test differentiated PD from MSA/PSP, whereas the PLM l-DOPA test differentiated between all three diagnoses.

EFNS/MDS-ES/ENS [corrected] recommendations for the diagnosis of Parkinson's disease

BACKGROUND

A Task Force was convened by the EFNS/MDS-ES Scientist Panel on Parkinson's disease (PD) and other movement disorders to systemically review relevant publications on the diagnosis of PD.

METHODS

Following the EFNS instruction for the preparation of neurological diagnostic guidelines, recommendation levels have been generated for diagnostic criteria and investigations.

RESULTS

For the clinical diagnosis, we recommend the use of the Queen Square Brain Bank criteria (Level B). Genetic testing for specific mutations is recommended on an individual basis (Level B), taking into account specific features (i.e. family history and age of onset). We recommend olfactory testing to differentiate PD from other parkinsonian disorders including recessive forms (Level A). Screening for pre-motor PD with olfactory testing requires additional tests due to limited specificity. Drug challenge tests are not recommended for the diagnosis in de novo parkinsonian patients. There is an insufficient evidence to support their role in the differential diagnosis between PD and other parkinsonian syndromes. We recommend an assessment of cognition and a screening for REM sleep behaviour disorder, psychotic manifestations and severe depression in the initial evaluation of suspected PD cases (Level A). Transcranial sonography is recommended for the differentiation of PD from atypical and secondary parkinsonian disorders (Level A), for the early diagnosis of PD and in the detection of subjects at risk for PD (Level A), although the technique is so far not universally used and requires some expertise. Because specificity of TCS for the development of PD is limited, TCS should be used in conjunction with other screening tests. Conventional magnetic resonance imaging and diffusion-weighted imaging at 1.5 T are recommended as neuroimaging tools that can support a diagnosis of multiple system atrophy (MSA) or progressive supranuclear palsy versus PD on the basis of regional atrophy and signal change as well as diffusivity patterns (Level A). DaTscan SPECT is registered in Europe and the United States for the differential diagnosis between degenerative parkinsonisms and essential tremor (Level A). More specifically, DaTscan is indicated in the presence of significant diagnostic uncertainty such as parkinsonism associated with neuroleptic exposure and atypical tremor manifestations such as isolated unilateral postural tremor. Studies of [(123) I]MIBG/SPECT cardiac uptake may be used to identify patients with PD versus controls and MSA patients (Level A). All other SPECT imaging studies do not fulfil registration standards and cannot be recommended for routine clinical use. At the moment, no conclusion can be drawn as to diagnostic efficacy of autonomic function tests, neurophysiological tests and positron emission tomography imaging in PD.

CONCLUSIONS

The diagnosis of PD is still largely based on the correct identification of its clinical features. Selected investigations (genetic, olfactory, and neuroimaging studies) have an ancillary role in confirming the diagnosis, and some of them could be possibly used in the near future to identify subjects in a pre-symptomatic phase of the disease.

Diffusion tensor imaging in idiopathic Parkinson's disease and multisystem atrophy (Parkinsonian type)

BACKGROUND

Differentiation between Parkinson's disease (PD) and atypical Parkinson syndromes (AP) is usually based on clinical examination, but can be challenging especially at early stages of the diseases. Diffusion tensor imaging (DTI) allows for differentiation between PD and AP with good specificity. It is a promising tool for clinical application, but has not been elaborated completely with respect to methodology and validity.

OBJECTIVE

In this study we evaluated differences of the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) within white brain matter between patients with PD and multisystem atrophy of the parkinsonian type (MSAp).

MATERIALS AND METHODS

DTI data of 9 PD and 9 MSAp patients were compared by means of a hypothesis-free whole-brain analysis algorithm (TBSS) focusing on changes within white matter.

RESULTS

We found significantly higher values of the ADC in the MSAp group in the anterior limb of the inner capsule, superior parts of the corona radiata, and lateral periputaminal white matter. Group differences in FA values were not significant.

CONCLUSION

Changes of the ADC close to the putamen proved most consistent and seem to be promising for the ongoing clinical implementation of DTI for the differentiation of hypokinetic-rigid movement disorders.