Discriminating mild parkinsonism: methods for epidemiological research

Associations of a toenail metal mixture with attention and memory in the Gulf long-term follow-up (GuLF) study

BACKGROUND

Research on metal-associated neurodegeneration has largely focused on single metals. Since metal exposures typically co-occur as combinations of both toxic and essential elements, a mixtures framework is important for identifying risk and protective factors. This study examined associations between toenail levels of an eight-metal mixture and attention and memory in men living in US Gulf states.

METHODS

We measured toenail concentrations of toxic (arsenic, chromium, lead, and mercury) and essential (copper, manganese, selenium, and zinc) metals in 413 non-smoking men (23-69 years, 46 % Black) from the Gulf Long-Term Follow-Up (GuLF) Study. Sustained attention and working memory were assessed at the time of toenail sample collection using the continuous performance test (CPT) and digit span test (DST), respectively. Associations between toenail metal concentrations and performance on neurobehavioral tests were characterized using co-pollutant adjusted general linear models and Bayesian Kernel Machine Regression.

RESULTS

Adjusting for other metals, one interquartile range (IQR) increase in toenail chromium was associated with a 0.19 (95 % CI: -0.31, -0.07) point reduction in CPT D Prime score (poorer ability to discriminate test signals from noise). One IQR increase in toenail manganese was associated with a 0.20 (95 % CI, -0.41, 0.01) point reduction on the DST Reverse Count (fewer numbers recalled). Attention deficits were greater among Black participants compared to White participants for the same increase in toenail chromium concentrations. No evidence of synergistic interaction between metals or adverse effect of the overall metal mixture was observed for either outcome.

CONCLUSIONS

Our findings support existing studies of manganese-related memory deficits and are some of the first to show chromium related attention deficits in adults. Longitudinal study of cognitive decline is needed to verify chromium findings. Research into social and chemical co-exposures is also needed to explain racial differences in metal-associated neurobehavioral deficits observed in this study.

Parkinsonian Hand or Clinician's Eye? Finger Tap Bradykinesia Interrater Reliability for 21 Movement Disorder Experts

BACKGROUND

Bradykinesia is considered the fundamental motor feature of Parkinson's disease (PD). It is central to diagnosis, monitoring, and research outcomes. However, as a clinical sign determined purely by visual judgement, the reliability of humans to detect and measure bradykinesia remains unclear.

OBJECTIVE

To establish interrater reliability for expert neurologists assessing bradykinesia during the finger tapping test, without cues from additional examination or history.

METHODS

21 movement disorder neurologists rated finger tapping bradykinesia, by Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and Modified Bradykinesia Rating Scale (MBRS), in 133 videos of hands: 73 from 39 people with idiopathic PD, 60 from 30 healthy controls. Each neurologist rated 30 randomly-selected videos. 19 neurologists were also asked to judge whether the hand was PD or control. We calculated intraclass correlation coefficients (ICC) for absolute agreement and consistency of MDS-UPDRS ratings, using standard linear and cumulative linked mixed models.

RESULTS

There was only moderate agreement for finger tapping MDS-UPDRS between neurologists, ICC 0.53 (standard linear model) and 0.65 (cumulative linked mixed model). Among control videos, 53% were rated >  0 by MDS-UPDRS, and 24% were rated as bradykinesia by MBRS subscore combination. Neurologists correctly identified PD/control status in 70% of videos, without strictly following bradykinesia presence/absence.

CONCLUSION

Even experts show considerable disagreement about the level of bradykinesia on finger tapping, and frequently see bradykinesia in the hands of those without neurological disease. Bradykinesia is to some extent a phenomenon in the eye of the clinician rather than simply the hand of the person with PD.

Wearable sensor-based gait analysis to discriminate early Parkinson's disease from essential tremor

BACKGROUND

Differentiating early-stage Parkinson's disease (PD) from essential tremor (ET) is challenging since they have some overlapping clinical features. Since early-stage PD may present with slight gait impairment and ET generally does not, gait analysis could be used to differentiate PD from ET using machine learning.

OBJECTIVE

To differentiate early-stage PD from ET via machine learning using gait and postural transition parameters calculated using the raw kinematic signal captured from inertial measurement unit (IMU) sensors.

METHODS

Gait and postural transition parameters were collected from 84 early-stage PD and 80 ET subjects during the Time Up and Go (TUG) test. We randomly split our data into training and test data. Within the training data, we separated the TUG test into four components: standing, straight walk, turning, and sitting to build weighted average ensemble classification models. The four components' weight indices were trained using logistic regression. Several ensemble models' leave-one-out cross-validation (LOOCV) performances were compared. Independent test data were used to evaluate the model with the best LOOCV performance.

RESULTS

The best weighted average ensemble classification model LOOCV results included an accuracy of 84%, Kappa of 0.68, sensitivity of 85.9%, specificity of 82.1%, and AUC of 0.912. Thirty-three gait and postural transition parameters, such as Arm-Symbolic Symmetry Index and 180° Turn-Max Angular Velocity, were included in Feature Group III. The independent test data achieved a 75.8% accuracy.

CONCLUSIONS

Our findings suggest that gait and postural transition parameters obtained from wearable sensors combined with machine learning had the potential to distinguish between early-stage PD and ET.

A Systematic Review of Physical Examination Components Adapted for Telemedicine

Introduction: The COVID-19 pandemic ushered in a rapid, transformative adoption of telemedicine to maintain patient access to care. As clinicians made the shift from in-person to virtual practice, they faced a paucity of established and reliable clinical examination standards for virtual care settings. In this systematic review, we summarize the accuracy and reliability of virtual assessments compared with traditional in-person examination tools. Methods: We searched PubMed, Embase, Web of Science, and CINAHL from inception through September 2019 and included additional studies from handsearching of reference lists. We included studies that compared synchronous video (except allowing for audio-only modality for cardiopulmonary exams) with in-person clinical assessments of patients in various settings. We excluded behavioral health and dermatological assessments. Two investigators abstracted data using a predefined protocol. Results: A total of 64 studies were included and categorized into 5 clinical domains: neurological (N = 41), HEENT (head, eyes, ears, nose, and throat; N = 5), cardiopulmonary (N = 5), musculoskeletal (N = 8), and assessment of critically ill patients (N = 5). The cognitive assessment within the neurological exam was by far the most studied (N = 19) with the Mini-Mental Status Exam found to be highly reliable in multiple settings. Most studies showed relatively good reliability of the virtual assessment, although sample sizes were often small (<50 participants). Conclusions: Overall, virtual assessments performed similarly to in-person exam components for diagnostic accuracy but had a wide range of interrater reliability. The high heterogeneity in population, setting, and outcomes reported across studies render it difficult to draw broad conclusions on the most effective exam components to adopt into clinical practice. Further work is needed to identify virtual exam components that improve diagnostic accuracy.

Potential of Whole-Body Vibration in Parkinson’s Disease: A Systematic Review and Meta-Analysis of Human and Animal Studies

Simple Summary

Exercise has shown to have a positive impact on both motor and non-motor functions in Parkinson’s Disease patients. However, particularly in later stages of the disease, reduced cognitive function and motor capacity may lead to an inability to stay physically active. Therefore, alternative strategies for patients with Parkinson’s Disease are necessary to minimize burden for patients, their families and public health care. Whole-Body Vibration could be such an alternative. Whole-Body Vibration is an exercise or treatment method in which subjects are exposed to a mechanical vibration while sitting, standing or exercising on a vibrating platform. Whole-Body Vibration is currently used for physiotherapy, sports and rehabilitation purposes. Whole-Body Vibration treatment is interesting because it affects both the body and brain. The potential of Whole-Body Vibration for, specifically, Parkinson’s Disease patients should be clarified for further application. For this purpose, we conducted an extensive systematic review of the articles investigating the effects of Whole-Body Vibrations (1) on animals and humans with Parkinson’s Disease and (2) on neuropathological Parkinson’s Disease mechanisms. The results show some potential of Whole-Body Vibration for Parkinson’s Disease patients. The recommendations provided by this review can be used by researchers and rehabilitative practitioners implementing Whole-Body Vibration as a treatment for Parkinson’s Disease patients.

Abstract

(1) Background: When the severity of Parkinson’s Disease (PD) increases, patients often have difficulties in performing exercises. Whole-Body Vibration (WBV) may be a suitable alternative. This systematic review aims to clarify if WBV shows potential as rehabilitative therapy for PD patients. (2) Methods: We searched several databases for controlled trials investigating the effects of WBV (1) on PD populations and (2) PD neuropathological mechanisms. We included both human and animal studies and performed meta-analyses. (3) Results: The studies on PD populations (14 studies) show an overall significant, but small, effect in favor of WBV (Hedges’ g = 0.28), for which the effects on stability (Hedges’ g = 0.39) and balance (Hedges’ g = 0.30) are the most prominent. The studies on the neuropathological mechanisms (18 studies) show WBV effects on neuroinflammation (Hedges’ g = –1.12) and several specific WBV effects on neurotransmitter systems, growth factors, neurogenesis, synaptic plasticity and oxidative stress. (4) Conclusions: The effects of WBV on human PD patients remains inconclusive. Nevertheless, WBV protocols with sufficient duration (≥3 weeks), session frequency (≥3 sessions/week) and vibration frequency (≥20 Hz) show potential as a treatment method, especially for motor function. The potential of WBV for PD patients is confirmed by the effects on the neuropathological mechanisms in mostly non-PD populations. We recommend high-quality future studies on both PD patients and PD mouse models to optimize WBV protocols and to examine the neuropathological mechanisms in PD populations.

Combined effects of virtual reality techniques and motor imagery on balance, motor function and activities of daily living in patients with Parkinson's disease: a randomized controlled trial

Background

Parkinson's disease (PD) is the second most prevalent neurodegenerative disorder, impairing balance and motor function. Virtual reality (VR) and motor imagery (MI) are emerging techniques for rehabilitating people with PD. VR and MI combination have not been studied in PD patients. This study was conducted to investigate the combined effects of VR and MI techniques on the balance, motor function, and activities of daily living (ADLs) of patients with PD.

Methods

This study was a single-centered, two-armed, parallel-designed randomized controlled trial. A total of 44 patients of either gender who had idiopathic PD were randomly allocated into two groups using lottery methods. Both groups received Physical therapy (PT) treatment, while the experimental group (N: 20) received VR and MI in addition to PT. Both groups received assigned treatment for three days a week on alternate days for 12 weeks. The Unified Parkinson’s Disease Rating Scale (UPDRS) (parts II and III), Berg Balance Scale (BBS), and Activities-specific Balance Confidence (ABC) Scale were used as outcome measures for motor function, balance, and ADLs. The baseline, 6^th, and 12^th weeks of treatment were assessed, with a 16^th week follow-up to measure retention. The data was analysed using SPSS 24.

Results

The experimental group showed significant improvement in motor function than the control group on the UPDRS part III, with 32.45±3.98 vs. 31.86±4.62 before and 15.05±7.16 vs. 25.52±7.36 at 12-weeks, and a p-value < 0.001. At 12 weeks, the experimental group's BBS scores improved from 38.95±3.23 to 51.36±2.83, with p-value < 0.001. At 12 weeks, the experimental group's balance confidence improved considerably, from 59.26±5.87to 81.01±6.14, with a p-value of < 0.001. The experimental group's ADL scores improved as well, going from 22.00±4.64 to 13.07±4.005 after 12 weeks, with a p-value of < 0.001.

Conclusion

VR with MI techniques in addition to routine PT significantly improved motor function, balance, and ADLs in PD patients compared to PT alone.

Trial registration

IRCT20200221046567N1. Date of registration: 01/04/2020

Mechanomyography and acceleration show interlimb asymmetries in Parkinson patients without tremor compared to controls during a unilateral motor task

The mechanical muscular oscillations are rarely the objective of investigations regarding the identification of a biomarker for Parkinson's disease (PD). Therefore, the aim of this study was to investigate whether or not this specific motor output differs between PD patients and controls. The novelty is that patients without tremor are investigated performing a unilateral isometric motor task. The force of armflexors and the forearm acceleration (ACC) were recorded as well as the mechanomyography of the biceps brachii (MMGbi), brachioradialis (MMGbra) and pectoralis major (MMGpect) muscles using a piezoelectric-sensor-based system during a unilateral motor task at 70% of the MVIC. The frequency, a power-frequency-ratio, the amplitude variation, the slope of amplitudes and their interlimb asymmetries were analysed. The results indicate that the oscillatory behavior of muscular output in PD without tremor deviates from controls in some parameters: Significant differences appeared for the power-frequency-ratio (p = 0.001, r = 0.43) and for the amplitude variation (p = 0.003, r = 0.34) of MMGpect. The interlimb asymmetries differed significantly concerning the power-frequency-ratio of MMGbi (p = 0.013, r = 0.42) and MMGbra (p = 0.048, r = 0.39) as well as regarding the mean frequency (p = 0.004, r = 0.48) and amplitude variation of MMGpect (p = 0.033, r = 0.37). The mean (M) and variation coefficient (CV) of slope of ACC differed significantly (M: p = 0.022, r = 0.33; CV: p = 0.004, r = 0.43). All other parameters showed no significant differences between PD and controls. It remains open, if this altered mechanical muscular output is reproducible and specific for PD.

Technologies Assessing Limb Bradykinesia in Parkinson's Disease

Background: The MDS-UPDRS (Movement Disorders Society – Unified Parkinson’s Disease Rating Scale) is the most widely used scale for rating impairment in PD. Subscores measuring bradykinesia have low reliability that can be subject to rater variability. Novel technological tools can be used to overcome such issues.

Objective: To systematically explore and describe the available technologies for measuring limb bradykinesia in PD that were published between 2006 and 2016.

Methods: A systematic literature search using PubMed (MEDLINE), IEEE Xplore, Web of Science, Scopus and Engineering Village (Compendex and Inspec) databases was performed to identify relevant technologies published until 18 October 2016.

Results: 47 technologies assessing bradykinesia in PD were identified, 17 of which offered home and clinic-based assessment whilst 30 provided clinic-based assessment only. Of the eligible studies, 7 were validated in a PD patient population only, whilst 40 were tested in both PD and healthy control groups. 19 of the 47 technologies assessed bradykinesia only, whereas 28 assessed other parkinsonian features as well. 33 technologies have been described in additional PD-related studies, whereas 14 are not known to have been tested beyond the pilot phase.

Conclusion: Technology based tools offer advantages including objective motor assessment and home monitoring of symptoms, and can be used to assess response to intervention in clinical trials or routine care. This review provides an up-to-date repository and synthesis of the current literature regarding technology used for assessing limb bradykinesia in PD. The review also discusses the current trends with regards to technology and discusses future directions in development.

Optical Hand Tracking: A Novel Technique for the Assessment of Bradykinesia in Parkinson's Disease

Background

Evaluation of therapies for Parkinson's disease (PD) may benefit from objective quantification of the separate movement components of bradykinesia (i.e., velocity, amplitude, and rhythm). This study evaluated the sensitivity and reliability of parameters derived from recently available optical hand tracking techniques for patient-friendly, automated quantification of bradykinesia of the upper extremity in PD.

Methods

Fifty-seven patients with PD and 57 healthy individuals (controls) performed repetitive finger tapping (RFT), alternating hand movements (AHM), and alternating forearm movements (AFM). Movement components of bradykinesia (i.e., velocity, frequency, amplitude, hesitations, and halts) were quantified using optical hand tracking. Reliability was quantified using intraclass correlation coefficients in a subgroup of 12 patients with PD and 12 controls (test-retest) and in all 57 controls (intra-trial).

Results

RFT and AHM were successfully recorded in 94% of all participants. Movement components differed between patients with PD and controls and were correlated with clinical ratings. Velocity and halt duration appeared to be most useful (i.e., the largest difference between the PD and control groups, good reliability) for the quantification of RFT, whereas frequency appeared to be most useful for the quantification of AHM. Other variables, such as frequency and amplitude of RFT, showed poor test-retest reliability, because they were susceptible to changes in movement strategy. AFM was excluded from the analysis because of problems with hand recognition.

Conclusion

Novel optical hand tracking techniques yield promising results for patient-friendly quantification of bradykinesia of the upper extremity in PD. Future work should aim to optimize optical hand tracking and reduce susceptibility to changes in strategy.

Parkinsonian signs are a risk factor for falls

BACKGROUND

Parkinsonian signs are common, non-specific findings in older adults and associated with increased rates of dementia and mortality. It is important to understand which motor outcomes are associated with parkinsonian signs.

OBJECTIVES

To determine the role of parkinsonian signs on fall rates among older adults.

METHODS

We conducted a longitudinal study of primary care patients from the University of Pennsylvania Health System. Adults over 55 years were assessed at baseline through surveys and a neurological examination. We recorded falls over the following 2 years. Parkinsonian signs were defined as the presence of 2 of 4 cardinal signs. Incident falls were compared between subjects with and without parkinsonian signs, and modified Poisson regression used to adjust for potential confounders in the relationship between parkinsonian signs and falls.

RESULTS

982 subjects with a mean age of 68 (s.d. 8.8) years participated. 29% of participants fell and 12% exhibited parkinsonian signs at baseline. The unadjusted RR for falls among individuals with parkinsonian signs was 1.36 (95% CI 1.05-1.76, p=0.02). After adjusting for age, cognitive function, urinary incontinence, depression, diabetes, stroke and arthritis, individuals with parkinsonian signs were still 38% more likely to fall than those without parkinsonian signs (RR 1.38, 95% CI 1.04-1.82; p=0.03). Falls among those with parkinsonian signs were more likely to lead to injury (53% vs 37%; p=0.04).

CONCLUSIONS

Parkinsonian signs are a significant, independent risk factor for falls. Early detection of this clinical state is important in order to implement fall prevention programs among primary care patients.

The Isothiocyanate Isolated from Moringa oleifera Shows Potent Anti-Inflammatory Activity in the Treatment of Murine Subacute Parkinson's Disease

The present study was aimed at estimating a possible neuroprotective effect of glucomoringin (GMG) [4-(α-L-rhamnopyranosyloxy)benzyl glucosinolate] bioactivated with the enzyme myrosinase to form the corresponding isothiocyanate [4-(α-L-rhamnopyranosyloxy)benzyl C; moringin] in the treatment or prevention of Parkinson's disease (PD). In this study, the beneficial effects of moringin were compared with those of pure GMG, not enzymatically activated, in an in vivo experimental mouse model of subacute PD. Subacute PD was induced in C57BL/6 mice by administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Mice were pretreated daily for 1 week with moringin (10 mg/kg +5 μL myrosinase/mouse) and with GMG (10 mg/kg). Behavioral evaluations were also performed to assess motor deficits and bradykinesia in MPTP mice. Besides, assuming that pretreatment with moringin could modulate the triggering of inflammatory cascade with a correlated response, we tested its in vitro anti-inflammatory activity by using a model of RAW 264.7 macrophages stimulated with lipopolysaccharide. Achieved results in vivo showed a higher efficacy of moringin compared with GMG not only to modulate the inflammatory pathway but also oxidative stress and apoptotic pathways. In addition, the greater effectiveness of moringin in countering mainly the inflammatory pathway has been corroborated by the results obtained in vitro. The relevance and innovation of the present study lie in the possible use of a safe formulation of a bioactive compound, resulting from exogenous myrosinase hydrolysis of the natural phytochemical GMG, which can be used in clinical practice as a useful drug for the treatment or prevention of PD.

Neuroprotective effects of Eucommia ulmoides Oliv. and its bioactive constituent work via ameliorating the ubiquitin-proteasome system

BACKGROUND

Parkinson's disease (PD) is a chronic neurodegenerative disorder characterized by a loss of dopaminergic neurons in the substantia nigra, decreased striatal dopamine levels, and consequent extrapyramidal motor dysfunction. The purpose of this study was to investigate potential in vivo protective effects of Duzhong against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), as well as the bioactive constituents against 1-methyl-4-phenylpyridinium (MPP(+)) toxicity in vitro.

METHODS

Male C57BL/6 mice were intraperitoneally administrated five consecutive injections of MPTP every 24 h at a dose of 30 mg/kg to induce an in vivo PD model. Pole and traction tests were performed in mice to evaluate motor deficits and bradykinesia after the final MPTP administration. The striatal levels of dopamine and its metabolites, 3,4-dihydroxyphenylacetic acid and homovanilic acid, were measured using a High-performance liquid chromatography-electrical conductivity detector. To further explore the bioactive constituents and protective mechanisms of Duzhong, seven compounds from Duzhong were tested on MPP(+)-treated SH-SY5Y cell lines in vitro. A proteasome enzymatic assay and Cell Counting Kit-8 were performed to examine proteasomal activity and cell viability of Duzhong-treated cells, respectively, after exposure to MPP(+) and proteasome inhibitor MG132.

RESULTS

Duzhong antagonized the loss of striatal neurotransmitters and relieved the associated anomaly in ambulatory locomotor activity in PD mice after a 3-day pre-treatment of Duzhong crude extract. The five Duzhong compounds attenuated MPP(+)-induced dysfunction of protease activity and reduced MG132-induced cytotoxicity.

CONCLUSION

Duzhong could serve as a potential candidate for PD treatment, and its mechanism involves the amelioration of the ubiquitin-proteasome system.

Clinician versus machine: reliability and responsiveness of motor endpoints in Parkinson's disease

BACKGROUND

Enhancing the reliability and responsiveness of motor assessments required to demonstrate therapeutic efficacy is a priority for Parkinson's disease (PD) clinical trials. The objective of this study is to determine the reliability and responsiveness of a portable kinematic system for quantifying PD motor deficits as compared to clinical ratings.

METHODS

Eighteen PD patients with subthalamic nucleus deep-brain stimulation (DBS) performed three tasks for evaluating resting tremor, postural tremor, and finger-tapping speed, amplitude, and rhythm while wearing a wireless motion-sensor unit (Kinesia) on the more-affected index finger. These tasks were repeated three times with DBS turned off and at each of 10 different stimulation amplitudes chosen to yield small changes in treatment response. Each task performance was video-recorded for subsequent clinician rating in blinded, randomized order. Test-retest reliability was calculated as intraclass correlation (ICC) and sensitivity was calculated as minimal detectable change (MDC) for each DBS amplitude.

RESULTS

ICCs for Kinesia were significantly higher than those for clinician ratings of finger-tapping speed (p < 0.0001), amplitude (p < 0.0001), and rhythm (p < 0.05), but were not significantly different for evaluations of resting or postural tremor. Similarly, Kinesia scores yielded a lower MDC as compared with clinician scores across all finger-tapping subscores (p < 0.0001), but did not differ significantly for resting and postural tremor.

CONCLUSIONS

The Kinesia portable kinematic system can provide greater test-retest reliability and sensitivity to change than conventional clinical ratings for measuring bradykinesia, hypokinesia, and dysrhythmia in PD patients.

PEP-1-PEA-15 protects against toxin-induced neuronal damage in a mouse model of Parkinson's disease

BACKGROUND

PEA-15 is abundantly expressed in both neurons and astrocytes throughout the brain. It is a multifunctional protein with the ability to increase cell survival via anti-apoptotic and anti-proliferative properties. However, the function of PEA-15 in neuronal diseases such as Parkinson's disease (PD) remains unclear. In this study, we investigated the protective effects of PEA-15 on neuronal damage induced by MPP(+) in neuroblastoma SH-SY5Y and BV2 microglia cells and in a MPTP-induced PD mouse model using cell-permeable PEP-1-PEA-15.

METHODS

PEP-1-PEA-15 was purified using affinity chromatography. Cell viability and DNA fragmentation were examined by MTT assay and TUNEL staining. Dopaminergic neuronal cell death in the animal model was examined by immunohistochemistry.

RESULTS

PEP-1-PEA-15 transduced into the SH-SY5Y and BV2 cells in a time- and dose-dependent manner. Transduced PEP-1-PEA-15 protected against MPP(+)-induced toxicity by inhibiting intracellular ROS levels and DNA fragmentation. Further, it enhanced the expression levels of Bcl-2 and caspase-3 while reducing the expression levels of Bax and cleaved caspase-3. We found that PEP-1-PEA-15 transduced into the substantia nigra and prevented dopaminergic neuronal cell death in a MPTP-induced PD mouse. Also, we showed the neuroprotective effects in the model by demonstrating that treatment with PEP-1-PEA-15 ameliorated MPTP-induced behavioral dysfunctions and increased dopamine levels in the striatum.

CONCLUSIONS

PEP-1-PEA-15 can efficiently transduce into cells and protects against neurotoxin-induced neuronal cell death in vitro and in vivo.

GENERAL SIGNIFICANCE

These results demonstrate the potential for PEP-1-PEA-15 to provide a new strategy for protein therapy treatment of a variety of neurodegenerative diseases including PD.

Rest tremor suppression may separate essential from parkinsonian rest tremor

Rest tremor at 4-6 Hz is typical for classical rest tremor (PT) of Parkinson's disease (PD). But rest tremor also appears in other tremor syndromes and may therefore cause a misdiagnosis. In this study we evaluated if suppression of tremor during movement onset is a characteristic feature of Parkinsonian Tremor distinguishing PT from Essential tremor (ET) and if this sign can be reliably diagnosed. Clinically diagnosed patients with PT (n = 44) and ET (n = 22) with rest tremor were included. Video sequences were recorded according to a standardized protocol focusing on the change of tremor amplitude during transition from rest to posture (test 1) or to a target-directed movement (test 2). These videos were assessed for rest tremor suppression by 4 reviewers (2 specialists and 2 residents) blinded to the clinical diagnosis and were compared to the personal assessment of an unblinded movement disorder specialist. Rest tremor suppression was found in 39/44 PD patients and in 2/22 patients with ET during the personal assessment. Rest tremor suppression showed a high sensitivity (0.92-1.00) and an acceptable specificity (0.69-0.95) for PD tremor in both tests. The interrater-reliability of the video-sequences was good to very good (κ 0.73-0.91). Less than 3% of the video sequences were misclassified. We conclude that the assessment of the suppression of rest tremor during movement initiation is a simple and reliable tool to separate PT from rest tremor in ET also suggesting that the mechanisms of rest tremor in these two diseases are different.

Neuroprotective Effects of San-Huang-Xie-Xin-Tang in the MPP(+)/MPTP Models of Parkinson's Disease In Vitro and In Vivo

San-Huang-Xie-Xin-Tang (SHXT), composed of Coptidis rhizoma, Scutellariae radix, and Rhei rhizoma, is a traditional Chinese medicine used for complementary and alternative therapy of cardiovascular and neurodegenerative diseases via its anti-inflammatory and antioxidative effects. The aim of this study is to investigate the protective effects of SHXT in the 1–methyl–4–phenylpyridinium (MPP⁺)/1–methyl–4–phenyl–1,2,3,6–tetrahydropyridine (MPTP) models of Parkinson's disease. Rat primary mesencephalic neurons and mouse Parkinson disease model were used in this study. Oxidative stress was induced by MPP⁺ in vitro and MPTP in vivo. In MPP⁺-treated mesencephalic neuron cultures, SHXT significantly increased the numbers of TH-positive neurons. SHXT reduced apoptotic signals (cytochrome and caspase) and apoptotic death. MPP⁺-induced gp91^phox activation and ROS production were attenuated by SHXT. In addition, SHXT increased the levels of GSH and SOD in MPP⁺-treated neurons. In MPTP animal model, SHXT markedly increased TH-positive neurons in the substantia nigra pars compacta (SNpc) and improved motor activity of mice. In conclusion, the present results reveal the evidence that SHXT possesses beneficial protection against MPTP-induced neurotoxicity in this model of Parkinson's disease via its antioxidative and antiapoptotic effects. SHXT might be a potentially alternative and complementary medicine for neuroprotection.

Screening questionnaires for parkinsonism: a systematic review

Parkinson's disease (PD) is a common, treatable movement disorder that often remains undiagnosed despite clinically manifest symptoms. Screening for parkinsonism could lead to improved detection and earlier treatment, and facilitate research studies of PD prevalence. In order to determine the feasibility of screening, this study evaluated the validity of previously developed screening questionnaires. We systematically searched online databases PubMed and EMBASE for English-language studies published between 1980 and 2009. In each database a "Parkinson(s) disease" or "parkinsonism" term was combined with a screening term ("screening instrument," "screening questionnaire," "screen" or "prevalence survey") and a validity term ("validation," "sensitivity" and "specificity"). Included studies reported the psychometric properties of at least one self-report questionnaire for parkinsonism. Twenty-seven studies met the inclusion criteria. From these studies, 9 screening questionnaires were identified. Sensitivity and specificity estimates varied widely. Sensitivity estimates were as high as 100% when questionnaires were tested among previously diagnosed PD patients and included a high number of parkinsonism specific items, but were as low as 48% when tested among early cases in a community-based sample. Specificity estimates were lower, ranging from 22 to 100%. An older sample, presence of multiple co-morbid conditions and lower literacy led to lower specificity estimates. Higher specificity estimates were seen when the screening questionnaires were administered by a physician. Screening questionnaires can detect symptomatic parkinsonism. However, the performance of these questionnaires varied based on the individual items, study sample, and method of administration. The performance of screening questionnaires in the detection of early or mild parkinsonism was modest.

The modified bradykinesia rating scale for Parkinson's disease: reliability and comparison with kinematic measures

Bradykinesia encompasses slowness, decreased movement amplitude, and dysrhythmia. Unified Parkinson's Disease Rating Scale-based bradykinesia-related items require that clinicians condense abnormalities in speed, amplitude, fatiguing, hesitations, and arrests into a single score. The objective of this study was to evaluate the reliability of a modified bradykinesia rating scale, which separately assesses speed, amplitude, and rhythm and its correlation with kinematic measures from motion sensors. Fifty patients with Parkinson's disease performed Unified Parkinson's Disease Rating Scale-directed finger tapping, hand grasping, and pronation-supination while wearing motion sensors. Videos were rated blindly and independently by 4 clinicians. The modified bradykinesia rating scale and Unified Parkinson's Disease Rating Scale demonstrated similar inter- and intrarater reliability. Raters placed greater weight on amplitude than on speed or rhythm when assigning a Unified Parkinson's Disease Rating Scale score. Modified bradykinesia rating scale scores for speed, amplitude, and rhythm correlated highly with quantitative kinematic variables. The modified bradykinesia rating scale separately captures bradykinesia components with interrater and intrarater reliability similar to that of the Unified Parkinson's Disease Rating Scale. Kinematic sensors can accurately quantify speed, amplitude, and rhythm to aid in the development and evaluation of novel therapies in Parkinson's disease.

Timed motor tests can detect subtle motor dysfunction in early Parkinson's disease

Early diagnosis of Parkinson's disease (PD) is important for putative neuroprotective therapies to be initiated in the earliest stage of the disease. We investigated whether a previously validated timed motor test (TMT) battery could detect subtle motor dysfunction in early PD patients and even in clinically unaffected limbs of strictly hemiparkinsonian patients. We assessed 107 PD patients (symptom duration <or=2 years; dopa-naive) and 100 healthy, age-matched controls with eight simple TMTs based on aspects of (a) walking, (b) writing, (c) single and double-handed pegboard performance, (d) finger tapping, and (e) diadochokinesis. We evaluated the ability of individual and combined TMTs to discriminate patients from controls using ROC curves. Second, we investigated whether these TMTs could identify motor dysfunction of the clinically unaffected limb in 42 strictly hemiparkinsonian patients. The pegboard dexterity test had the best ROC curve (AUC 0.97; 95% sensitivity, 89% specificity) for patients versus controls. It retained reasonable accuracy when testing the clinically unaffected limb of hemiparkinsonian patients versus the mean of right and left-hand scores in controls (AUC 0.73). The pegboard dexterity test is a sensitive and inexpensive instrument to detect motor dysfunction in early PD. Therefore, it may be worth evaluating as a diagnostic tool in everyday clinical practice to assess patients with early symptomatic PD, or as part of a more elaborate screening battery in a defined population at risk.

Fucoidan protects against dopaminergic neuron death in vivo and in vitro

Parkinson's disease is a neurodegenerative disorder of uncertain pathogenesis characterized by a loss of dopaminergic neurons in substantia nigra pars compacta, and can be modeled by the neurotoxin 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP). Oxidative stress may contribute to MPTP- and Parkinson's disease-related neurodegeneration. Fucoidan is a sulfated polysaccharide extracted from brown seaweeds which possesses a wide variety of biological activities including potent antioxidative effects. Here we investigated the effect of fucoidan treatment on locomoter activities of animals, striatal dopamine and its metabolites and survival of nigral dopaminergic neurons in MPTP-induced animal model of Parkinsonism in C57/BL mice in vivo and on the neuronal damage induced by 1-methyl-4-phenylpyridinium (MPP(+)) in vitro, and to study the possible mechanisms. When administered prior to MPTP, fucoidan reduced behavioral deficits, increased striatal dopamine and its metabolites levels, reduced cell death, and led to a marked increase in tyrosine hydroxylase expression relative to mice treated with MPTP alone. Furthermore, we found that fucoidan inhibited MPTP-induced lipid peroxidation and reduction of antioxidant enzyme activity. In addition, pre-treatment with fucoidan significantly protected against MPP(+)-induced damage in MN9D cells. Taken together, these findings suggest that fucoidan has protective effect in MPTP-induced neurotoxicity in this model of Parkinson's disease via its antioxidative activity.

Substantia nigra hyperechogenicity in depressive subjects relates to motor asymmetry and impaired word fluency

BACKGROUND

Substantia nigra hyperechogenicity (SNH) is a characteristic transcranial sonography (TCS) finding in Parkinson's disease (PD). SNH, found also in about 10% of healthy adults, was related to a subclinical malfunction of the nigrostriatal dopaminergic system on positron emission tomography studies. Both, liability for developing PD and frequency of SNH were found to be increased in depressed subjects. Here, we investigated whether SNH in depression is related to motor or cognitive abnormalities resembling early PD.

METHODS

Fourty-one patients with major depressive disorder and 15 with adjustment disorder with depressed mood were studied clinically and with TCS.

RESULTS

Frequency of SNH was similar in both groups (39, 33%; Chi-square test, P = 0.70). Larger SN echogenic size correlated with larger right-to-left asymmetry of finger tapping (Spearman test, r = 0.37, P = 0.009) and lower verbal fluency (r = -0.35, P = 0.038). These correlations were stronger in patients at ages >/= 50 years (r = 0.52, P = 0.007; r = -0.50, P = 0.020), and, independently from age, in patients with reduced echogenicity of brainstem raphe suggested to reflect alteration of the serotonergic system (r = 0.40, P = 0.045; r = -0.51, P = 0.044). Whereas bilateral sum score of finger tapping was negatively correlated with severity of depression on the beck depression inventory (r = -0.50, P = 0.001) and the Hamilton depression rating scale (r = -0.34, P = 0.019), no correlation was found between depression severity and tapping asymmetry, or between depression severity and verbal fluency.

CONCLUSION

Data suggest that TCS detects a subgroup of patients with depression characterized by symptoms of early parkinsonism who are possibly at an elevated risk of later developing definite PD.

Variability of EMG patterns: a potential neurophysiological marker of Parkinson's disease?

OBJECTIVE

This study evaluated whether changes in the electromygraphic (EMG) pattern during rapid point-to-point movements in individuals diagnosed with PD can: (1) distinguish PD subjects from healthy subjects and (2) determine if differences in the EMG pattern reflect disease severity in PD.

METHODS

Three groups of 10 PD subjects and 10 age/sex-matched healthy subjects performed rapid 72 degree point-to-point elbow flexion movements. PD subjects were divided, a priori, into three groups based upon off medication motor UPDRS score.

RESULTS

Measures related to the EMG pattern distinguished all PD subjects and 9 out of 10 healthy subjects, resulting in 100% sensitivity. Further, significant correlations were shown between EMG measures and the motor UPDRS score. After 30 months, the one healthy subject whose EMG pattern was abnormal was reexamined. The EMG measures remained abnormal and the motor UPDRS score went from 0 to 10. Parkinson's disease was diagnosed.

CONCLUSION

Measures related to the variability of the EMG pattern during rapid point-to-point movements provide neurophysiological measures that objectively distinguish PD subjects from healthy subjects. These measures also correlate with disease severity.

SIGNIFICANCE

EMG measures may provide a non-invasive measure that is sensitive and specific for identifying individuals with PD.

Catalpol attenuates nitric oxide increase via ERK signaling pathways induced by rotenone in mesencephalic neurons

Catalpol has been shown to rescue neurons from kinds of damage in vitro and in vivo in previous reports. However, the effect of catalpol on the nitric oxide (NO) system via MAPKs signaling pathway of mesencephalic neurons largely remains to be verified. The current study examined that whether catalpol modulated NO and iNOS increase by rotenone in primary mesencephalic neurons and investigated its underlying signaling pathways. Present results indicated that catalpol inhibited primary mesencephalic neurons from apoptosis by morphological assay, immunocytochemistry and flow cytometric evaluation. Moreover, the ERK signaling pathway plays an important role in NO-mediated degeneration of neuron. The current results suggest that catalpol is a potential agent for the prevention of neurons apoptosis by regulating NO and iNOS increase in ERK-mediated neurodegenerative disorders.

Diagnostic performance of clinical motor and non-motor tests of Parkinson disease: a matched case-control study

BACKGROUND AND PURPOSE

The diagnosis of Parkinson disease (PD) is made typically on the basis of motor abnormalities. PD is now recognized to have both motor and non-motor manifestations, indicating a need for the development of reliable non-motor diagnostic tests for PD. The aim of the present study was to compare the accuracy of various clinical motor and non-motor tests for the diagnosis of PD.

METHODS

Forty-five PD patients (Hoehn and Yahr stages 1-3; mean age 59.5 +/- 10.0 years) and 45 healthy controls matched for gender and age completed a clinimetric motor test battery to assess limb bradykinesia, tremor and balance. Non-motor tests consisted of depression, anxiety and smell identification ratings. Area under the receiver operator characteristic curve (AUC) analysis was used.

RESULTS

We found that smell identification was the most accurate predictor of the presence of PD within the overall group of patients and matched control subjects (AUC = 0.886) and also in the subgroups of mild severity (Hoehn and Yahr stages 1-1.5; AUC = 0.923), young-onset (AUC = 0.888) and female PD patients (AUC = 0.797). The second best diagnostic test was the grooved pegboard test for the clinically most affected body side.

CONCLUSIONS

We conclude that olfactory function is the most accurate diagnostic predictor within a heterogeneous sample of patients with PD.

Planning and control of sequential rapid aiming in adults with Parkinson's disease

Eight people with Parkinson's disease (PD), 8 age-matched older adults, and 8 young adults executed 3-dimensional rapid aiming movements to 1, 3, 5, and 7 targets. Reaction time, flight time, and time after peak velocity to the 1st target indicated that both neurologically healthy groups implemented a plan on the basis of anticipation of upcoming targets, whereas the PD group did not. One suggested reason for the PD group's deficiency in anticipatory control is the greater variability in their initial force impulse. Although the PD group scaled peak velocity and time to peak velocity similarly to the other groups, their coefficients of variation were greater, making consistent prediction of the movement outcome difficult and thus making it less advantageous to plan too far in advance. A 2nd finding was that the PD group exhibited increased slowing in time after peak velocity in the final segments of the longest sequence, whereas the other 2 groups did not. The increased slowing could be the result of a different movement strategy, increased difficulty modulating the agonist and antagonist muscle groups later in the sequence, or both. The authors conclude that people with PD use more segmented planning and control strategies than do neurologically healthy older and young adults when executing movement sequences and that the locus of increased bradykinesia in longer sequences is in the deceleration phase of movement.

Unified Parkinson's disease rating scale motor examination: are ratings of nurses, residents in neurology, and movement disorders specialists interchangeable?

The Unified Parkinson's Disease Rating Scale (UPDRS) is widely used for the clinical evaluation of Parkinson's disease (PD). We assessed the rater variability of the UPDRS Motor examination (UPDRS-ME) of nurse practitioners, residents in neurology, and a movement disorders specialist (MDS) compared to a senior MDS. We assessed the videotaped UPDRS-ME of 50 PD patients. Inter-rater and intra-rater variability were estimated using weighted kappa (kappa(w)) and intraclass correlation coefficients (ICC). Additionally, inter-rater agreement was quantified by calculation of the mean difference between 2 raters and its 95% limits of agreement. Intra-rater agreement was also estimated by calculation of a 95% repeatability limits. The kappa(w) and ICC statistics indicated good to very good inter-rater and intra-rater reliability for the majority of individual UPDRS items and the sum score of the UPDRS-ME in all raters. However, for inter-rater agreement, it appeared that both nurses, residents, and the MDS consistently assigned higher scores than the senior MDS. Mean differences ranged between 1.7 and 5.4 (all differences P < 0.05), with rather wide 95% limits of agreement. The intra-rater 95% repeatability limits were rather wide. We found considerable rater difference for the whole range of UPDRS-ME scores between a senior MDS and nurse practitioners, residents in neurology, and the MDS. This finding suggests that the amount by which raters may disagree should be quantified before starting longitudinal studies of disease progression or clinical trials. Finally, evaluation of rater agreement should always include the assessment of the extent of bias between different raters.

Learning and retention of movement sequences in Parkinson's disease

The purpose of this study was to examine motor learning and retention given extensive practice in two fundamentally different movement sequences. One sequence was a memory-driven task (performing a series of whole body positions from memory) and the other a context-driven task (buttoning). Practice took place over 3 weeks, with performance measured weekly; retention was measured weekly for 3 weeks after practice. There were 7 people with Parkinson's disease (PD) and 7 age-matched neurologically healthy people who participated in this study. Both groups improved performance on both tasks with practice, with the majority of the change for the PD group occurring between 1 and 2 weeks of practice. Although those with PD did not necessarily perform as well as age-matched controls, they learned both sequences in a manner similar to age-matched controls, and exhibited retention across the 3-week retention interval. If people with PD are given sufficient practice they can learn and retain both memory-based and context-driven movement sequences as well as age-matched controls. The results provide support for maintaining physical activity and for intervention through movement therapy.

[Assessment of idiopathic Parkinson's disease in physical medicine and rehabilitation]

Parkinson's disease (PD) is a chronic disease associated with motor impairments (bradykinesia, rigidity, tremor and postural disorders), cognitive disorders and dysautonomia. Most symptoms are greatly improved by dopatherapy during the first stages, then signs of treatment ineffectiveness or intolerance occur that signal the beginning of motor and cognitive decline. This evolution signified the need to develop an effective tool to measure the effectiveness of drugs or surgery in PD and has had the Movement Disorder Society to propose 20 years ago a tool to assess such patients: the Unified Parkinson's Disease Rating Scale (UPDRS). This scale has a good internal consistency and a good interrater reliability. Yet, some impairments, especially of cognitive origin, are evaluated too succinctly and need complementary scales. As well, other disorders such as bladder disorders are not included, nor is quality of life studied despite the impact of PD on daily life. Specific scales have been proposed. UPDRS may be well-adapted to PD follow-up in the physical medicine and rehabilitation context by measuring treatment effectiveness, detecting Dopa ineffectiveness or complications and assessing patients' handicap in daily activities. The evolution of UPDRS will improve the qualities of the scale and contribute to better determining the various stages of the disease.

The SCOPA–Motor Scale for assessment of Parkinson's disease is a consistent and valid measure

OBJECTIVE

The SCOPA-Motor Scale (S-MS) for assessment of Parkinson's disease (PD), contains 21 items in three domains: Motor examination, Disability, and Complications. Our objective was to validate the S-MS Spanish version.

STUDY DESIGN AND SETTING

This validation study was based on a multicenter, cross-sectional, one-point-in-time evaluation design. The applied measures were: Unified Parkinson's Disease Rating Scale-3.0 (UPDRS); S-MS; PD Global Evaluation (PDGE); and Clinical Global Impression of severity (CGI). Completeness of data collection, floor and ceiling effect, internal consistency, precision, and construct and discriminative validity were analyzed in 151 PD patients.

RESULTS

Scores from S-MS were fully computable. Floor effect was high for Complications (43.7%). Cronbach's alpha was > 0.90 for every domain, and item-total correlation was > 0.70 except for Examination. Standard error of measurement (SEM) ranged from 0.40 to 2.4. Convergent validity with corresponding UPDRS sections yielded coefficients > 0.90. Discriminative validity across Hoehn and Yahr (HY) and CGI stages was significant (Kruskal-Wallis, P < .0001). Insofar as internal consistency was concerned, alpha-values of the Examination sections were marginally higher for the UPDRS than for the S-MS (a finding perhaps accounted for by redundancy in this part of the UPDRS).

CONCLUSION

The S-MS is a consistent and valid scale, shorter by almost half than the UPDRS.

An intermittent, controlled-rate, slow progressive degeneration model of Parkinson's disease: antiparkinson effects of Sinemet and protective effects of methylphenidate

The causes of nigrostriatal neuron degeneration in Parkinson's disease (PD) are not known, but it has been suggested that exogenous or endogenous factors or neurotoxins may play a role. The degree of vulnerability to neurotoxins or other potential mediators of nigral dopamine cell death is thought to be important in understanding Parkinson's disease. In most animal models, the rate of terminal degeneration and corresponding functional impairment is too rapid to investigate effectively either cell vulnerability or the potential benefits of some neuroprotective treatments. In the present study, a new model of Parkinson's disease is described that might help in addressing the issue of nigral cell vulnerability and to evaluate interventions with clinical potential. 6-Hydroxydopamine (6-OHDA) was infused in escalating, intrastriatal doses over several weeks. Control animals received multiple infusions of vehicle at the same volume. Behavioral testing was carried out between each infusion, including forelimb-use and somatosensory function. A symptomatic threshold was established for each animal, indicating the amount of neurotoxin required to induce a stable deficit. Oral administration of L-DOPA (Sinemet) ameliorated limb-use asymmetries acutely. An immunocytochemical assay for tyrosine hydroxylase, a dopamine cell marker, revealed a partial loss of immunoreactive cells in the substantia nigra. Animals that were co-administered methylphenidate (MPH), a dopamine transport inhibitor, along with the 6-OHDA were spared from the behavioral and neurochemical effects of 6-OHDA, despite receiving more than twice as much neurotoxin as controls. These data suggest that establishing a symptomatic threshold preclinically may help researchers evaluate potential treatments and model individual and group resistance to nigrostriatal insults.

Analysis of the course of Parkinson's disease under dopaminergic therapy: Performance of ?fast tapping? is not a suitable parameter

In addition to clinical rating scales, instrumental methods are employed frequently for assessment of performance or motor deficits in Parkinson's disease (PD). Many studies have analyzed such parameters in cross-sectional studies. We employed a battery of tests to investigate fine motor performance over a period of 4 years in 411 de novo parkinsonian patients from the Prado study. Specifically, tapping and pegboard testing ("plugging") were evaluated and performance on these tests compared with clinical ratings. Plugging scores correlated well with tapping scores and clinical rating at each assessment timepoint. Both tests also showed significant differences to healthy controls. Nevertheless "fast tapping" was found to be less impaired than was plugging in de novo patients. Over time, it was observed that plugging scores, but not tapping scores, exhibited changes that paralleled movements in clinical score. Plugging scores exhibited a marked response to dopaminergic therapy whereas fast tapping showed no therapeutic response. Fast tapping is certainly not suitable for assessment of bradykinesia or hypokinesia, and does not respond to dopaminergic therapy.

Olfaction and Parkinson's syndromes: its role in differential diagnosis

PURPOSE OF REVIEW

Marked olfactory dysfunction (hyposmia) is a frequent and early abnormality in Parkinson's disease. We review recent advances related to its cause and its clinical relevance with respect to the differential diagnosis of Parkinsonian syndromes.

RECENT FINDINGS

Marked olfactory dysfunction occurs in Parkinson's disease and dementia with Lewy bodies but is not found in progressive supranuclear palsy and corticobasal degeneration. In multiple system atrophy, the deficit is mild and indistinguishable from cerebellar syndromes of other aetiologies, including the spino-cerebllar ataxias. This is in keeping with evidence of cerebellar involvement in olfactory processing, which may also help to explain recent findings of mild olfactory dysfunction in essential tremor. Smell testing remains, however, a clinically relevant tool in the differential diagnosis of indeterminate tremors. Intact olfaction has also been reported recently in Parkin disease (PARK 2) and vascular Parkinsonism. The relevance of sniffing ability to olfaction and a possible role of increased tyrosine hydroxylase and dopamine in parts of the olfactory bulb are issues of current interest with respect to pathophysiology. The early or 'pre-clinical' detection of Parkinson's disease is increasingly recognized as an area in which olfactory testing may be of value.

SUMMARY

Research findings have confirmed a role for olfactory testing in the differential diagnosis of movement disorders, and suggest that this approach is currently underused in clinical practice. Validated test batteries are now available that may prove to be of practical use in the differential diagnosis of Parkinsonian syndromes and indeterminate tremors.

Development of the Behavioral Assessment and Research System (BARS) to detect and characterize neurotoxicity in humans

The Behavioral Assessment and Research System (BARS) is a computer-based testing system designed to assess neurobehavioral function in humans. It was developed to provide a series or battery of neurobehavioral tests optimized for the detection of neurotoxicity in non-mainstream human populations, specifically people with limited education or literacy. Key to meeting this goal were simply-stated instructions divided into an elemental series of steps, a 9BUTTON response unit to replace the computer keyboard for responding, and spoken instructions. Modifications all underwent serial testing in target populations to successively hone the changes to be more effective. A similar process was followed when developing adjustable parameters, test reliability assessments, and when implementing these tests with populations from different cultural groups and children. The principles and experiences that guided the development of BARS should inform the development of future testing systems to ensure that the new tests can be used with non-mainstream populations, which may be increasingly subject to neurotoxic exposures.

The Unified Parkinson's Disease Rating Scale (UPDRS): status and recommendations

The Movement Disorder Society Task Force for Rating Scales for Parkinson's Disease prepared a critique of the Unified Parkinson's Disease Rating Scale (UPDRS). Strengths of the UPDRS include its wide utilization, its application across the clinical spectrum of PD, its nearly comprehensive coverage of motor symptoms, and its clinimetric properties, including reliability and validity. Weaknesses include several ambiguities in the written text, inadequate instructions for raters, some metric flaws, and the absence of screening questions on several important non-motor aspects of PD. The Task Force recommends that the MDS sponsor the development of a new version of the UPDRS and encourage efforts to establish its clinimetric properties, especially addressing the need to define a Minimal Clinically Relevant Difference and a Minimal Clinically Relevant Incremental Difference, as well as testing its correlation with the current UPDRS. If developed, the new scale should be culturally unbiased and be tested in different racial, gender, and age-groups. Future goals should include the definition of UPDRS scores with confidence intervals that correlate with clinically pertinent designations, "minimal," "mild," "moderate," and "severe" PD. Whereas the presence of non-motor components of PD can be identified with screening questions, a new version of the UPDRS should include an official appendix that includes other, more detailed, and optionally used scales to determine severity of these impairments.

Detection of behavioral impairments correlated to neurochemical deficits in mice treated with moderate doses of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine

Overt behavioral symptoms of Parkinson's disease (PD) do not occur until over 80% of the striatal dopamine content has been lost. Diagnosis of the disorder relies on identifying clinical symptoms including akinesia, resting tremor, and rigidity. In retrospect, behavioral deficits are observed several years prior to diagnosis. Behavioral manifestations in the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of PD, such as changes in general locomotor activity and rotorod performance, require large doses of MPTP and are often transient. We hypothesized that, as in PD, subtle behavioral changes also occur in the MPTP model. In this paper, we demonstrate that mice treated with moderate doses of the dopaminergic toxin MPTP display deficits in behavioral parameters that are significantly correlated with the loss of striatal dopamine. In addition, these behavioral measures are correlated to dopamine transporter, vesicular monoamine transporter, and tyrosine hydroxylase expression and are improved following L-DOPA administration. Detection of dopamine-modulated behavioral changes in moderately depleted MPTP mice will allow for more efficacious use of this model in PD research.

Practice effects in three-dimensional sequential rapid aiming in Parkinson's disease

One hypothesized role of the basal ganglia, based largely on findings in Parkinson's disease (PD) patients, is the control of movement sequences. We examined changes in performance with practice of a movement sequence in PD patients and age-matched controls (n = 8 per group). Subjects practiced a complex three-dimensional sequential aiming task over 2 days, completing 180 trials, with the goal to minimize response time within specified accuracy limits. The results indicated that both groups became faster in planning the movement, and both groups moved more quickly through the sequence with practice. The PD group's decrease in movement time occurred primarily within the first 45 trials, whereas the control group continued to improve through the first 150 trials. Flight time (time between targets) to a small target decreased with practice in both groups, but flight time to a large target decreased only in the control group. This finding indicates that error corrective processes are more amenable to practice than ballistic processes in people with PD. There was little evidence that either group improved their performance by planning shorter (lower) trajectories, but rather increased mean velocity. Contact time (time on target) decreased with practice in both groups, and there were no group differences. These data indicate that practice can improve performance, both in planning and in specific execution processes.

Parkinsonian syndromes and differential diagnosis

PURPOSE OF REVIEW

Physicians are becoming more astute at diagnosing the various parkinsonian syndromes but in clinical practice it is still often difficult to make the correct diagnosis. This review discusses new evidence that may aid physicians in correctly identifying parkinsonian syndromes.

RECENT FINDINGS

We will review the newest developments in the areas of clinical features, electrophysiologic tests, autonomic tests, neuropsychologic tests, imaging, and biochemical markers which may be of value in differentiating these syndromes.

SUMMARY

Accurate diagnosis of the parkinsonian syndromes has important implications for patients, in terms of both prognosis and management. Investigations reported during the last year provide new insight into the distinguishing features of these syndromes and may help clinicians and researchers define these disorders more precisely.

Diagnosing Parkinson's disease using videotaped neurological examinations: validity and factors that contribute to incorrect diagnoses

Field work is commonly required in movement disorders research. Sending neurologists into the field can be logistically challenging and costly. Alternatively, neurological examinations may be videotaped and reviewed later. There is little knowledge of the validity of the videotaped neurological examination in the diagnosis of Parkinson's disease (PD). We examined the validity of the videotaped Unified Parkinson's Disease Rating Scale (UPDRS) motor examination in the diagnosis of PD, and sought to determine which factors are associated with incorrect diagnoses. PD patients and controls were enrolled in a familial aggregation study between August of 1998 and June of 2000, and as part of that study each was examined by a physician who performed an in-person UPDRS motor examination. Each also underwent a second, videotaped UPDRS motor examination. Based on the review of this videotape, a neurologist, who was blinded to the previous clinical diagnosis, assigned a diagnosis of PD or normal. A total of 211 of 231 PD patients (sensitivity = 91.3%), and 170 of 172 controls (specificity = 98.8%) were correctly identified based on the videotape. True positives had a higher mean rest tremor score (1.7 vs. 0.3; P < 0.001), action tremor score (0.9 vs. 0.3; P < 0.001), bradykinesia score (11.2 vs. 7.4; P = 0.02), and disease of longer mean duration (8.9 vs. 5.8 years; P = 0.001) than false negatives. False negatives did not differ from true positives in terms of age, total dose of levodopa, Hoehn and Yahr score, or rigidity, gait and posture, or facial masking scores (each assessed during the in-person examination). The videotaped UPDRS motor examination is a useful means of diagnosing PD and provides an alternative approach for the diagnosis of PD in field studies. A limitation is that patients with milder PD of shorter duration may not be recognized as PD.