Search

Objective: Main clinical features of vascular parkinsonism (VP) are rigidity, fixed face, and short stepping gait. VP remains difficult to diagnose based on clinical features from patients with Parkinson’s disease (PD) without rest tremor. Olfactory dysfunction is a non-motor symptom in idiopathic PD. We investigated whether olfactory function can distinguish VP from PD. Method: Participants were comprised of 13 patients with VP, 40 non-demented patients with akinetic-type PD, and 40 age-matched controls. Olfactory function was examined using the Odor Stick Identification Test for Japanese (OSIT-J), which evaluates the detection of 12 odorants familiar to Japanese participants. Results: Corrected odor identification scores in OSIT-J were 8.2 ± 1.5 (mean ± SD) points in patients with VP, 3.2 ± 2.5 in PD patients, and 7.1 ± 3.0 in normal subjects. These were significantly higher in VP than those in PD patients (p

Self-similar stochastic processes and broad probability distributions are ubiquitous in Nature and in many man-made systems. The brain is a particularly interesting example of (natural) complex system where those features play a pivotal role. In fact, the controversial yet experimentally validated “criticality hypothesis” explaining the functioning of the brain implies the presence of scaling laws for correlations. Recently, we have analyzed a collection of rest tremor velocity signals recorded from patients affected by Parkinson’s disease, with the aim of determining and hence exploiting the presence of scaling laws. Our results show that multiple scaling laws are required in order to describe the dynamics of such signals, stressing the complexity of the underlying generating mechanism. We successively extracted numeric features by using the multifractal detrended fluctuation analysis procedure. We found that such features can be effective for discriminating classes of signals recorded in different experimental conditions. Notably, we show that the use of medication (L-DOPA) can be recognized with high accuracy.

SUMMARY Parkinson’s disease (PD) is characterized clinically by the hallmark motor signs of bradykinesia, rest tremor and rigidity. Current pharmacological management goals include control of motor symptoms as well as prevention and management of motor complications including motor fluctuations and dyskinesias. While the use of levodopa revolutionized the pharmacological management of PD, multiple other agents and strategies have emerged with many demonstrable, albeit sometimes controversial, advantages to a ‘levodopa’ only approach. Despite these developments, the progressive nature of PD requires vigilance and creativity from clinicians as both motor and nonmotor complications grow in number and severity over time.

This paper aims to investigate the effect of continuous sensory electrical stimulation (SES) on the suppression of a Parkinsonian rest tremor. Fourteen patients with Parkinson’s disease participated in this study. Three wrist muscles were electrically stimulated on sensory level under motor threshold. Intensity of stimulation was determined for each muscle of each patient as the maximum tolerable current amplitude that does not induce muscle contraction. Tri-axial gyro sensors were attached to three upper limb segments. The angular velocity of each segment was measured for each of the three sessions, i.e., PRE-, ON- and POST- stimulations. Outcome measures were the tremor amplitude and main frequency of each axis in the power spectrum. Decrease in tremor amplitude was significant at ON and POST sessions in finger and at POST session in hand and forearm. Decrease in main frequency was significant mainly at ON session. About one-third of patients showed reduction in tremor power at ON-stimulation and at POST-stimulation. Subjects with suppression of tremor showed greater initial tremor amplitude than those without suppression. Continuous SES suppressed the Parkinsonian rest tremor. The results suggest that the properties of tremor-generating loop may be altered by continuous SES and the effect lasts temporarily.

Dirkx et al.1 studied 73 patients with tremor-dominant Parkinson disease (PD) and recorded their tremor before and after levodopa using forearm EMG. They concluded that there were 2 types of postural tremor in these patients: reemergent tremor, noted in 81% of the patients, and pure postural tremor, present in 19%. They noted that reemergent tremor is a “continuation of resting tremor.” This confirms our report in which we coined the term “reemergent tremor” to draw attention to this type of postural tremor, often more troublesome in patients with PD than the typical rest tremor, and to differentiate it from essential tremor (ET).2

Lower leg rest tremor is an uncommon symptom of neurological disease. Review of the files of 16 patients who presented with lower leg tremor (average age 58 ± 16 years; average disease duration 6.8 ± 8.5 years) yielded a diagnosis of Parkinson's disease (PD) in 5 and probable multiple system atrophy (MSA) in 3. In 4 patients with an indeterminate diagnosis, cardiac MIBG SPECT was positive in 3, indicating PD, and negative in one, suggesting MSA. Two patients each had psychogenic tremor and drug-induced parkinsonism. Although lower leg tremor is considered an unusual presentation of PD, it should raise suspicions of MSA and other neurodegenerative disorders. © 2010 Movement Disorder Society

Essential tremor is a well-defined syndrome of postural and kinetic tremor in a characteristic distribution. In some patients, impaired tandem walking, intention tremor, and rest tremor are also seen. An increasing body of clinical, neuropathological, and epidemiologic evidence suggests that essential tremor is a heterogeneous disorder. The evidence is discussed in this update. Recent advances in the treatment of this condition are also reviewed.

The objective was to design, build, and assess Kinesia, a wireless system for automated assessment of Parkinson's disease (PD) tremor. The current standard in evaluating PD is the Unified Parkinson's Disease Rating Scale (UPDRS), a qualitative ranking system typically completed during an office visit. Kinesia integrates accelerometers and gyroscopes in a compact patient-worn unit to capture kinematic movement disorder features. Objectively quantifying PD manifestations with increased time resolution should aid in evaluating efficacy of treatment protocols and improve patient management. In this study, PD subjects performed the tremor subset of the UPDRS motor section while wearing Kinesia. Quantitative kinematic features were processed and highly correlated to clinician scores for rest tremor (r(2) = 0.89), postural tremor (r(2) = 0.90), and kinetic tremor (r(2) = 0.69). The quantitative features were used to develop a mathematical model that predicted tremor severity scores for new data with low errors. Finally, PD subjects indicated high clinical acceptance.

Objectives - To test new electronic equipment, TREMOR, for quantitative registration of rest tremor and kinetic tremor of the extremities. Patients and methods - The tremor intensity of rest tremor and kinetic tremor was studied in 14 multiple sclerosis (MS) patients. Clonazepam was used in an open study in 11 MS patients to evaluate the sensitivity of TREMOR, compared to the clinical observations. Results - We found no diurnal variations in tremor. Five patients discontinued the trial because of side effects due to clonazepam. Clonazepam significantly reduced clinically rest tremor in all 6 patients and clinically kinetic tremor in 5 patients. Tested by TREMOR all patients showed significant reduction in rest tremor and kinetic tremor. Correlation between electronic assessment of kinetic tremor, clinical score and Peg board test were good. Conclusion - TREMOR was found useful for assessment of the severity of tremor in patients with kinetic tremor and thereby avoid intra- and interobserver variation.

The physiology differs in the many forms of human tremor. Tremors may derive from mechanical oscillations, mechanical reflex oscillations, normal central oscillators, and pathologic central oscillators. Methods of studying tremor include accelerometry and electromyography (EMG). An excellent method consists of accelerometry and EMG combined with spectral analysis and weighting of the body part, which allows separation of tremors coming from mechanical reflex and central oscillators. Physiologic tremor is a mechanical tremor with a possible contribution of the normal 8-12 Hz central oscillator; exaggerated physiologic tremor is a mechanical reflex tremor. Essential tremor (ET) comes from a central oscillator that can be easily influenced with sensory input. The classic rest tremor of Parkinson's disease (PD) comes from a central oscillator that seems less easily influenced with sensory input but can be affected by transcranial magnetic stimulation. Other tremors with central oscillators are palatal tremor and orthostatic tremor. Other tremors whose physiology involves central loops includes cerebellar tremor and cortical tremor. Neuropathic tremors may be a result of delays in peripheral loops, but central oscillators play a role in some.

When levodopa (L-dopa) is administered intravenously to patients with severe Parkinson's disease, a therapeutic response may be seen within a 1/2 hour. However, when the drug is administered orally in lower doses to less disabled patients, a delay of 1–2 weeks often occurs before motor deficits start to improve. Recent data from the Early versus Late Levodopa study suggest that maximum improvement at a fixed dosage may take ≤3 months to develop. A nonspecific feeling of well-being and reduced tiredness are often the first benefits to occur, followed by greater alacrity and less stiffness. Rest tremor is slower to improve, but may eventually disappear altogether and remain well controlled throughout the rest of the course of the malady. Gait, balance, and speech may also improve, but the effect is usually more modest and a decline is common after several years of sustained treatment.

Classical Parkinsonian rest tremor typically fluctuates over time and can be provoked by stressful situations. We quantified and compared the influence of different provocation methods on classical rest tremor severity. The effect of counting backwards from 100, tapping of the contralateral foot and a Stroop test on the Unified Parkinson's Disease Rating Scale (UPDRS) III rest tremor scores and the accelerometrically measured tremor amplitudes (total power) were analyzed in 18 patients with Parkinson's disease and a Type I tremor. Each of the three provocation methods increased the UPDRS III rest tremor score by 1-2 and the total power by 1-2 orders of magnitude compared with baseline (P < 0.001). The maximal effect was reached on average after 2-3 minutes of provocation. The effects were not significantly different. Provocations clearly influence the result of clinical rest tremor ratings, with the kind of provocation being of minor importance. We therefore suggest that each assessment of Parkinsonian rest tremor should include a systematic provocation and this should be formally included in future versions of the UPDRS.

Keywords: re-emergent tremor; emergent tremor; basal ganglia infarction; moyamoya disease

Parkinson’s disease (PD) is a complex neurodegenerative disorder that encompasses both motor and non-motor symptoms. These symptoms and their severity are typically assessed by scale based measures in a clinical setting. Scale- based assessments of PD patients undergoing bilateral subthalamic nucleus deep brain stimulation surgery (STN-DBS) such as the Unified Parkinson Disease Rating Scale (UPDRS) are commonly used in a clinical setting to assess symptom severity and progression. However, the subjective nature of these and other clinical scales call into question both the sensitivity and accuracy of patient assessment over time. An objective quantification of rest and postural tremor of PD patients who have undergone STN-DBS has never been conducted. Furthermore, objective technologies that quantitatively assess the effects of STN-DBS programming on full body rest and postural tremor have not yet been fully explored. The study employed the use of a full body kinematic Inertial Motion Unit (IMU) based technology in order to study the short term and long term effects of Deep Brain Stimulation (DBS) on idiopathic PD patients. Not surprisingly both whole body rest and upper postural tremor reduced by six months following DBS surgery. An average best setting was identified for tremor reduction.

Background Tremor in dystonia has been described as a postural or kinetic abnormality. In recent series, however, patients with idiopathic adult-onset dystonia also displayed rest tremor. Methods The frequency and distribution of rest tremor were studied in a cohort of 173 consecutive Italian patients affected by various forms of idiopathic adult-onset dystonia attending our movement disorder clinic over 8 months. Results Examination revealed tremor in 59/173 patients (34%): 12 patients had head tremor, 34 patients had arm tremor, whilst 13 patients presented tremor in both sites. Head tremor was postural in all patients, whereas arm tremor was postural/kinetic in 28 patients, only at rest in one and both postural/kinetic and at rest in 18 patients. Patients with tremor were more likely to have segmental/multifocal dystonia. Patients who had rest tremor (either alone or associated with action tremor) had a higher age at dystonia onset and a greater frequency of dystonic arm involvement than patients with action tremor alone or without tremor. Conclusions Both action and rest tremor are part of the tremor spectrum of adult-onset dystonia and are more frequently encountered in segmental/multifocal dystonia. The higher age at dystonia onset and the greater frequency of arm dystonia in patients with rest tremor may have pathophysiological implications and may account, at least in part, for the previous lack of identification of rest tremor as one possible type of tremor present in dystonia.

Essential tremor (ET) is amongst the most commonly encountered neurological disorders. Its hallmark feature is kinetic tremor. However, other tremors may also occur in ET patients, creating considerable diagnostic confusion amongst treating physicians. Hence, characterizing the prevalence and clinical accompaniments of these other tremors is of value. Surprisingly, there are few data on the prevalence of rest tremor in ET patients, and even fewer data on the clinical correlates of such tremor.Eight hundred and thirty-one patients in four distinct settings (population, genetics study, study of environmental epidemiology, brain bank) underwent a detailed videotaped neurological examination that was reviewed by a senior movement disorders neurologist. Rest tremor was evaluated in several positions (seated, standing, lying down).The prevalence of rest tremor whilst seated or standing was lowest in the population-based setting (1.9%), highest in the brain bank study (46.4%) and intermediate in the remaining two settings (9.6% and 14.7%, respectively). Rest tremor was restricted to the arms and was not observed in the legs. Rest tremor was associated with older age, longer disease duration (in some studies), greater tremor severity and, to some extent, the presence of cranial tremors.Rest tremor can be a common clinical feature of ET. Its prevalence is highly dependent on the setting in which patients are evaluated, ranging from as low as 1% to nearly 50%. Rest tremor seems to emerge as a clinical feature with advancing disease. The anatomical substrates for this type of tremor remain unknown at present.

Tremor is an involuntary rhythmic oscillation of a body part, mediated by alternating contractions of reciprocally acting muscles. While tremor can be classified in many ways, categorizing tremor based on its positional properties (resting vs. action) is the most clinically helpful. This chapter discusses how to describe patients with different tremors.

Various clinical tests have been advocated to differentiate psychogenic tremor (PT) from organic tremor (OT). These include, for example, the change of tremor characteristics upon distraction, entrainment, co-activation or loading [1–3]. The “pointing test” was introduced more recently. In an elegant study, subjects with various types of tremor were instructed to perform a rapid unilateral ballistic movement towards a switch following a visual cue, while tremor was observed in the contralateral hand [4]. Subjects included 11 patients with resting tremor caused by Parkinson’s disease (PD), 10 patients with essential tremor (ET), seven with psychogenic tremor, and 10 normal volunteers who purposely imitated tremors. In all patients with psychogenic tremor and in all normal volunteers, the ballistic movement of one hand led to a transient cessation of tremor within the contralateral hand. This clinical observation was supported by polymyography. In contrast, the tremor did not cease in the two groups with organic tremor (patients with PD or ET). The authors suggested that this pointing test might have a relevant role for identifying psychogenic tremor [4]. Schwingenschuh et al. used a variant of the pointing test in their study- which was one test in a test battery- and partially reproduced these findings, showing a clear tremor pause during the pointing test in 5 of 12 patients with psychogenic tremor [5]. None of 25 patients with organic tremor showed such a tremor pause (test specificity: 100% ), although a decreased amplitude during contralateral ballistic movements was noted in four of these 25 patients. Such amplitude reductions during contra-lateral ballistic movements can also occur in PD patients [6], but complete tremor cessation during the pointing test has never been described for organic tremors. Here, we report an abnormal pointing test in a PD patient with a classic rest tremor, confirmed both clinically and using accelerometry, suggesting that the clinical utility of this test is imperfect.

Low frequency rest tremor is one of the cardinal signs of Parkinson's disease and some of its animal models. Current physiological studies and models of the basal ganglia differ as to which aspects of neuronal activity are crucial to the pathophysiology of Parkinson's disease. There is evidence that neural oscillations and synchronization play a central role in the generation of the disease. However, parkinsonian tremor is not strictly correlated with the synchronous oscillations in the basal ganglia networks. Rather, abnormal basal ganglia output enforces abnormal thalamo-cortical processing leading to akinesia, the main negative symptom of Parkinson's disease. Parkinsonian tremor has probably evolved as a downstream compensatory mechanism.

Tremor rating scales (TRSs) are used commonly in the clinical assessment of tremor, but the relationship of a TRS to actual tremor amplitude has never been quantified. Consequently, the resolution of these scales is unknown, and the clinical significance of a 1-point change in TRS is uncertain. We therefore sought to determine the change in tremor amplitude that corresponds to a 1-point change in a typical 5-point TRS. Data from five laboratories were analysed, and 928 patients with various types of hand tremor were studied. Hand tremor was quantified with a graphics tablet in three different labs, an accelerometer in three labs and a mechanical-linkage device in one lab. Tremor in writing, drawing, horizontal posture, rest and finger-nose testing was graded using a variety of TRSs. The relationship between TRS scores and tremor amplitude was computed for each task and laboratory. A logarithmic relationship between a 5-point (0-4) TRS and tremor amplitude (T, measured in centimetres) was found in all five labs, despite widely varying rating scales and transducer methodology. Thus, T2/T1 = 10(alpha(TRS2-TRS1)). The value of alpha ranged from 0.414 to 0.441 for writing, 0.355-0.574 for spiral drawing, 0.441 to 0.488 for rest tremor, 0.266-0.577 for postural tremor and 0.306 for finger-nose testing. For alpha = 0.3, 0.4, 0.5, 0.6 and 0.7, the ratios T2/T1 for a 1-point decrease in TRS are 0.501, 0.398, 0.316, 0.251 and 0.200. Therefore, a 1-point change in TRS represents a substantial change in tremor amplitude. Knowledge of the relationship between TRS and precise measures of tremor is useful in interpreting the clinical significance of changes in TRS produced by disease or therapy.

The objective of this study is to evaluate the responsiveness of items of the Activities of Daily Living (ADL) and Motor section of the Unified Parkinson's Disease Rating Scale (UPDRS) in patients with Parkinson's Disease (PD). A standardized Response Mean (SRM) per item was calculated using data of four trials (n=376) that randomised patients with early PD to dopamine agonist (DA) monotherapy or placebo. In the ADL section, the SRMs ranged from −0.04 (no effect) to −0.50 (moderate effect). Hand functions were the most responsive ADL items with ‘handwriting’ showing the largest response. Self-assessed symptoms were the least responsive. In the Motor section, SRMs ranged from −0.09 to −0.60 with bradykinesia items showing the largest response, especially the item ‘finger taps’. The tremor items showed the smallest response, however, rest tremor arms was much more responsive than rest tremor of the head and legs or postural tremor. SRMs in the placebo group ranged from 0.08 to −0.21 in the ADL section and from 0.03 to −0.35 in the Motor section. ADL and motor items have comparable and mostly small effect sizes. The most responsive items are in the ADL section hand functions and in the Motor section bradykinesia items. A more responsive ADL section would omit the self-assessed symptoms and the Motor section would retain only rest tremor arms of the tremor items.

A 78-year-old man presented with a 15-year history of chronic constipation. At age 68, he experienced a nearcomplete loss of his sense of smell. Recently, he has developed an unusual sleep disorder, characterized by abrupt and at times combative behavior during the night that has resulted in injury to his spouse on two separate occasions; he is referred to a sleep disorders clinic. For most physicians, this medical history would not immediately bring Parkinson’s disease (PD) to mind. Yet, accumulating clinical and pathological evidence suggests it should. The traditional “textbook” description of PD defines the disease as a progressive disorder characterized by the triad of rigidity, bradykinesia, and rest tremor. A large body of evidence suggests that these features are due to degeneration of the dopaminergic nigrostriatal system. Although these clinical features typically lead a patient to the door of the neurologist, it is now increasingly clear that parkinsonism is only one aspect of a multifaceted and complex disorder. Furthermore, it is increasing clear that at least some of these nonparkinsonian features can precede the onset of parkinsonism by years and perhaps even decades. This essay argues that parkinsonism represents the disease as seen through the somewhat myopic lens of the neurologist, whereas in reality, parkinsonism only represents the tip of the iceberg that makes up this diverse disease (Fig 1). If one accepts this view, then the time has come to radically rethink the complex of features that constitute the disorder, which might be better viewed as a “centrosympathomyenteric neuronopathy.” The implications of this thesis are of more than academic importance. A failure to reevaluate how we view this disease at a time when our knowledge about its clinical and pathological features is expanding rapidly will adversely affect not only efforts to improve the diagnosis and management of the patients that we care for, but also is likely to impede research into the cause of the disease and attempts to slow or halt its progression.

A 62-year-old man presents with an intermittent tremor in his left hand and some vague discomfort in the left arm. Physical examination shows a minimal rest tremor in the left hand that disappears with use of the limb, mild rigidity at the left wrist and elbow, slowness of finger tapping with the left hand, and decreased arm swing on the left while walking. How should he be evaluated and treated?

Tremorine-induced tremors model is used to evaluate antiparkinsonian drugs because rest tremor is a sign that distinguishes Parkinson's disease (PD) from other diseases. The effects of crude ethanolic extract (CEE) and total acetate fraction (TAF) of Plumbago scandens were investigated at several doses. These extracts at doses of 125 and 250 mg/kg i.p. failed to reduce tremors in tremorine-treated mice. TAF showed significant effects only at a dose of 500 mg/kg. Both CEE and TAF at doses of 1000 and 2000 mg/kg i.p. suppressed the tremors in a dose-dependent fashion for 60 min. Biperiden, an anticholinergic drug, was used as standard at a dose of 3 mg/kg i.p. This study suggests that P. scandens is a plant with possible therapeutic value for PD.

Parkinsonian signs are present in 40% of older people. Factor analysis of the motor section of the Unified Parkinson's Disease Rating Scale (UPDRS) in patients with Parkinson's disease (PD) has identified several principal domains, including rigidity, axial function, and rest tremor. We hypothesized that if Parkinsonian signs in the elderly were due to basal ganglia dysfunction that this same constellation of factors (rigidity, axial function, rest tremor) would emerge in a factor analysis. We carried out factor analysis, using the principal component method with orthogonal (varimax) rotation, on motor UPDRS scores in community-dwelling elderly without PD. A modified (10-item) version of the motor portion of the UPDRS was administered to 1,339 older adults living in the Washington Heights-Inwood community and it was found that Parkinsonian signs were present in 537 (40.1%). Three factors (rigidity, axial function. and rest tremor) were obtained from the factor analysis and, together, explained 67.4% of the variance. A second factor analysis was carried out excluding the 26 participants with rest tremor, and two factors (rigidity, axial function) emerged. These data support the view that Parkinsonian signs in older adults might be due to basal ganglia dysfunction, a possibility that requires further exploration. © 2004 Movement Disorder Society

Although rest tremor is the typical form of tremor associated with Parkinson's disease (PD), particularly the tremor-dominant subtype,1 parkinsonian patients may also exhibit postural tremor. In many parkinsonian patients, this postural tremor emerges after a latency of a few seconds or even minutes. In our original description, we coined the term "re-emergent tremor" to differentiate this postural tremor from essential tremor, which occurs without any latency, and to link it to PD rest tremor that is "reset" after some latency when a new holding posture is assumed.2 The relationship of this re-emergent tremor to the typical rest tremor is supported by the observation that this tremor shares many characteristics with the typical rest tremor, such as the same, 3 to 5-Hz frequency, occasional supinating-pronating component, and relatively good response to dopaminergic therapy. Rarely, postural tremor, occurring after a brief (2-4 seconds) latency can be seen even without observable rest tremor.3 In most patients with PD, it is the postural (re-emergent) tremor that is more troublesome for them than the typical rest tremor, because this re-emergent tremor interferes with their ability to hold objects, such as newspapers, against gravity and results in spilling of liquids. Postural tremor of PD is often misdiagnosed as essential tremor, and this diagnostic challenge can be further confounded when both conditions coexist.4 When that occurs, the postural tremor is present without latency, although the amplitude may gradually increase as the underlying re-emergent tremor becomes more evident.

Parkinson disease is a slowly progressive neurodegenerative disorder with a varied clinical picture and a variable rate of progression. Recently, there have been some studies conducted to assess the diagnostic accuracy and other clinical aspects of the disease. In the absence of a biomarker the clinical diagnosis is imprecise. This leads to a significant number of misdiagnoses, especially in early disease. Assessment of the clinical features suggests that an accuracy of 90% may be the highest that can be expected using current diagnostic criteria. In addition to bradykinesia, which is a core symptom, different types of tremors occur. Whereas the rest tremor is characteristic, action tremor, re-emergent tremor and orthostatic tremor may occur in Parkinson disease. Symptomatic treatments are quite effective in early disease but clinical course is complicated by the appearance of motor fluctuations and dyskinesias in more advanced disease. Non-motor complications, such as cognitive, psychiatric and autonomic problems, become bothersome and disabling in some patients.

The progression of mild parkinsonian signs in the absence of idiopathic Parkinson’s disease in aging is unclear. This study aims to identify predictors of the evolution of mild parkinsonian signs in non-demented older adults. Two hundred ten participants (76.25 ± 7.10 years, 57 % women) were assessed at baseline and 1-year follow-up. Mild parkinsonian signs were defined as the presence of bradykinesia, rigidity and/or rest tremor. Depending upon the presence of these features at baseline and follow-up, participants were divided into one of four groups (no, transient, persistent or new-onset mild parkinsonian signs). Physical function was assessed using gait velocity. Ninety-five participants presented with mild parkinsonian signs at baseline. At 1-year follow-up, 59 demonstrated persistent mild parkinsonian signs, while 36 recovered (i.e., transient). Participants with persistent mild parkinsonian signs were older (79.66 ± 7.15 vs. 75.81 ± 7.37 years, p = 0.01) and evidenced slower gait velocity (90.41 ± 21.46 vs. 109.92 ± 24.32 cm/s, p < 0.01) compared to those with transient mild parkinsonian signs. Gait velocity predicted persistence of mild parkinsonian signs, even after adjustments (OR: 0.96, 95 % CI: 0.94–0.98). Fifty-five participants demonstrated new-onset of mild parkinsonian signs. In comparison to participants without mild parkinsonian signs, presence of cardiovascular but not cerebrovascular disease at baseline was associated with new-onset mild parkinsonian signs. Our study reveals that gait velocity was the main predictor of persistent mild parkinsonian signs, whereas cardiovascular disease was associated with new-onset mild parkinsonian signs. These findings suggest a vascular mechanism for the onset of mild parkinsonian signs and a different mechanism, possibly neurodegenerative, for the persistence of mild parkinsonian signs.

The aim of this article is to point out that an incongruity of gait disorder (either in relation to the presenting movement disorder or incongruity with any type of organic gait disorder) is a useful clue in diagnosing psychogenic movement disorders. To illustrate this, we present a case series of patients with various types of psychogenic movement disorders (rest tremor, myoclonus, dystonia, and chorea). Incongruity of the walking pattern with the presenting movement disorder was a revealing diagnostic clue in all cases. "Incongruity" is currently a main plank in the diagnosis of psychogenic conditions. Our series emphasizes that incongruity of the gait pattern may be the most important sign in a patient where it is otherwise difficult to establish whether the movement disorder is congruous or incongruous with an organic disorder.

by Vrutang Kumar Shah and Harish Palanthandalam-Madapusi

Mild parkinsonian signs (MPS) and gait abnormalities are common in aging, but the association between MPS and objective gait measures is not established in the elderly. This study aims to identify the link between MPS and quantitative gait measures, as well as to determine the pathogenesis of MPS in non-demented community-dwelling older adults without idiopathic Parkinson’s disease or other parkinsonian syndromes. Three hundred seventy-four non-demented older adults (mean age, 76.44 ± 6.71 years, 57 % women) participated in this study, where comprehensive neurological and medical assessments were conducted. We defined MPS based on the presence of any one of bradykinesia, rigidity, or rest tremor. Velocity and spatial, temporal, and variability gait parameters were recorded using an instrumented walkway. The associations of MPS and gait parameters as well as the relationship of individual MPS with medical illnesses were assessed with linear regressions controlling for key covariates. Participants with MPS walked slower and with disturbed spatial and variability components of gait compared to those without MPS. Bradykinesia was associated with worse spatial and variability gait parameters. This association was only significant for axial bradykinesia, but not for the presence of bradykinesia in the limbs. Cerebrovascular disease (β = .20, p

The effect of chronic high frequency deep brain stimulation (DBS) on rest tremor was investigated in subjects with Parkinson’s disease (PD). Eight PD subjects with high amplitude tremor (Group 1) and eight PD subjects with low amplitude tremor (Group 2, used as a reference group) were examined by a clinical neurologist and tested with a velocity laser to quantify time and frequency domain characteristics of tremor. Possible rebound effects in rest tremor when DBS was stopped for 60 min were also explored. Participants received DBS of the internal globus pallidus (GPi) (n=7), the subthalamic nucleus (STN) (n=6) or the ventrointermediate nucleus of the thalamus (Vim) (n=3). Tremor was recorded with a velocity laser under two conditions of DBS (on–off) and two conditions of medication ( l -Dopa on–off). Correlations between clinical and experimental results for tremor amplitude was 0.70 with no medication and no stimulation. In Group 1, DBS decreased tremor amplitude but also increased spectral concentration and median frequency significantly. Under medication, the changes in tremor with and without stimulation were not statistically significant (Group 1). When stimulation was stopped for 60 min, a rebound in tremor amplitude was observed and median frequency remained stable in Group 1. None of the comparisons examined produced significant effects in Group 2. Taken together, these results suggest that beyond its effect on tremor amplitude DBS acted also on tremor frequency and did not modify tremor characteristics in subjects with low amplitude tremor.

In this paper, we present two modular systems for Parkinson's disease diagnosis. Also, we compare the frequency and chaotic behavior of rest tremor velocity in the index finger of some parkinsonian and healthy subjects. The proposed methods consist of two different modules, first, high-dimensional features are compressed by local linear and nonlinear principal component analysis (PCA) techniques and then, the features are classified by neural classifiers. The results indicate the efficiency of modular systems in Parkinson's disease diagnosis.

Tremor is a common symptom of Parkinson's disease (PD). The underlying pathophysiology of parkinsonian rest tremor is not well understood. Rest tremor is less responsive to dopaminergic therapy than are symptoms of bradykinesia and rigidity. This paper reviews the effects of 1 mg daily oral rasagiline, as monotherapy and as adjunct therapy, on parkinsonian tremor. A literature search of the EMBASE database was conducted to identify relevant articles in English published between 2000 and October, 2012 using the search terms "rasagiline," or "Azilect®," or "Agilect®," and refined using the terms "Parkinson's disease" and "clinical trial." Of 22 identified publications, two large placebo-controlled trials of rasagiline monotherapy (TEMPO and ADAGIO) and two large placebo-controlled trials of rasagiline as adjunctive therapy with levodopa (PRESTO and LARGO) specifically evaluated the effect of rasagiline on tremor using the Unified Parkinson's Disease Rating Scale (UPDRS) motor examination. Prospective and post-hoc analyses from these phase III studies show rasagiline monotherapy significantly improved tremor symptoms in early PD, independent of disease duration, compared with placebo. In levodopa-treated patients with motor fluctuations who were already receiving optimized dopaminergic treatment, the addition of rasagiline adjunct therapy significantly improved tremor symptoms. Significant improvement was evident as early as 10 weeks from treatment initiation. Tremor symptoms also improved in a subset of patients with severe tremor when rasagiline was added to their existing PD treatment regimen. These data suggest that rasagiline used as monotherapy and as adjunctive therapy is effective for reducing tremor severity in patients with PD.

Since the original description of the health effects of inhaled occupational manganese (Mn) by Couper in 1837, an extensive literature details the clinical syndrome and pathophysiology of what was thought to be a rare condition. In the last decade, conventional wisdom regarding the clinicopathological effects of Mn has been challenged. Past exposures to Mn were an order of magnitude higher than modern exposures in developed countries; therefore, the clinical syndrome seen in the time of Couper is no longer typical of modern Mn exposed workers. Parkinsonism (rigidity, bradykinesia, rest tremor, and postural instability) is present in 15% of Mn-exposed workers in welding industries, and these parkinsonian signs are associated with reduced health status and quality of life. These parkinsonian signs also overlap considerably with the clinical findings seen in early stages of Parkinson's disease (PD); although, molecular imaging suggests that Mn-exposed workers have dopaminergic dysfunction in a pattern unique from PD. Furthermore, geographic information system studies demonstrate that regions of the US with high industrial Mn emissions have an increased incidence of PD and increased PD associated mortality. This review will contrast historical, descriptive human studies in Mn-exposed subjects with more recent data and will suggest a research agenda for the 21st century.

A 71-year-old man presented with a 6-month history of rest tremor and slowness in his left hand. Apart from mild left parkinsonism, neurologic examination was unremarkable. Because response to l-dopa, up to 600 mg/d, was lacking, [123I]FP-CIT (123I- N -ω-fluoropropyl-2β-carbomethoxy-3β-[4-iodophenyl]nortropane) SPECT was prescribed with unexpected results: transverse and coronal slices showed the right striatum to be moved upward and medially, suggesting a structural compression rather than degenerative damage (figure). Brain MRI revealed the presence of a frontal meningioma. Caution is required when interpreting DaTscan findings,1,2 and morphologic imaging should always be performed first.

The diagnosis of adult-onset primary dystonia (AOPD) is mainly clinical, but requires the exclusion of any secondary causes. AOPD is characterised by sustained involuntary muscle contraction resulting in one or more body parts moved away from their neutral position. No other neurological sign is observed, apart from tremor. The 1998 Movement Disorder Society Consensus on Tremor states indeed that tremor and dystonia can be associated, defining the tremor affecting a dystonic body part as ‘dystonic tremor’, and the tremor affecting a non-dystonic body part as ‘tremor associated …

Background Observation of the signals recorded from the extremities of Parkinson’s disease patients showing rest and/or action tremor reveal a distinct high power resonance peak in the frequency band corresponding to tremor. The aim of the study was to investigate, using quantitative measures, how clinically effective and less effective deep brain stimulation protocols redistribute movement power over the frequency bands associated with movement, pathological and physiological tremor, and whether normal physiological tremor may reappear during those periods that tremor is absent. Methods The power spectral density patterns of rest and action tremor were studied in 7 Parkinson’s disease patients treated with (bilateral) deep brain stimulation of the subthalamic nucleus. Two tests were carried out: 1) the patient was sitting at rest; 2) the patient performed a hand or foot tapping movement. Each test was repeated four times for each extremity with different stimulation settings applied during each repetition. Tremor intermittency was taken into account by classifying each 3-second window of the recorded angular velocity signals as a tremor or non-tremor window. Results The distribution of power over the low frequency band (7.5 Hz – normal physiological tremor) revealed that rest and action tremor show a similar power-frequency shift related to tremor absence and presence: when tremor is present most power is contained in the tremor frequency band; when tremor is absent lower frequencies dominate. Even under resting conditions a relatively large low frequency component became prominent, which seemed to compensate for tremor. Tremor absence did not result in the reappearance of normal physiological tremor. Conclusion Parkinson’s disease patients continuously balance between tremor and tremor suppression or compensation expressed by power shifts between the low frequency band and the tremor frequency band during rest and voluntary motor actions. This balance shows that the pathological tremor is either on or off, with the latter state not resembling that of a healthy subject. Deep brain stimulation can reverse the balance thereby either switching tremor on or off.

Rest tremor was quantified in the index finger tip of 16 patients with Parkinson’s disease (PD) receiving deep brain stimulation (DBS) of the ventro-intermediate nucleus (Vim) of the thalamus, the subthalamic nucleus (STN), or the internal part of the globus pallidus (GPi) while being off l -dopa for 12 h. Clinically, without DBS, tremor amplitude varied from absent to high. Tremor was recorded continuously for about 5 min under three conditions of DBS repeated twice, namely, effective frequency (E), ineffective frequency (I), and no DBS (O). No changes in tremor were observed across conditions in subjects with little or no tremor. However, in subjects with moderate to large amplitude tremor, DBS decreased tremor amplitude to near normal values within a few seconds. Generally, transitions were progressive and occurred with a varying time delay. Occasionally, tremor escaped from control regardless of the stimulation condition considered. In some cases tremor amplitude in one condition appeared to depend on the preceding condition. Finally, the results were reproducible on two consecutive days. We conclude that tremor control with DBS follows specific dynamical rules, which must be compatible with the hypotheses proposed regarding the underlying mechanisms of DBS.

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.

The main problem of tremor is the damage caused to the quality of the life of patients, especially those at more advanced ages. There is not a consensus yet about the origins of this disorder, but it can be examined in the correlations between the biological signs of aging and the tremor characteristics. This work sought correlations between the osmotic fragility of erythrocytes and features extracted from electromyographic (EMG) activity resulting from physiological tremor in healthy patients (N=44) at different age groups (24-87 years). The osmotic fragility was spectrophotometrically evaluated by the dependence of hemolysis, provided by the absorbance in 540 nm (A 540 ), on the concentration of NaCl. The data were adjusted to curves of sigmoidal regression and characterized by the half transition point (H 50 ), amplitude of lysis transition ( dx ) and values of A 540 in the curve regions that characterize the presence of lysed (A 1 ) and preserved erythrocytes (A 2 ). The approximate entropy was estimated from EMG signals detected from the extensor carpi ulnaris muscle during the movement of the hand of subjects holding up a laser pen towards an Archimedes spiral, fixed in a whiteboard, and from an acelerometer fixed at the pen. The evaluations were carried out with the laser pen at rest, at the center of the spiral, and in movement from the center to the outside and from outside to the center. The correlations among the parameters of osmotic fragility, tremor, gender and age were tested. Negative correlations with age were found for A 1 and dx. With the hand at rest, a positive correlation with H 50 was found for the approximate entropy. Negative correlations with H 50 were found for the entropy with the hand in movement, as from the center to the outside or from the outside to the center of the spiral. In neurological healthy individuals, the increase in the erythrocyte osmotic fragility was associated with a decrease in the approximate entropy for rest tremor and with an increase of the entropy for movement tremor. This suggests that the neuromuscular degeneration associated with tremor entails also the mechanisms involved in the breakdown of structural homeostasis of the erythrocyte membrane.

We analyzed rest tremor, one of the etiologically most elusive hallmarks of Parkinson disease(PD), in 12 consecutive PD patients during a specific task activating the locus coeruleus (LC) to investigate a putative role of noradrenaline (NA) in tremor generation and suppression. Clinical diagnosis was confirmed in all subjects by reduced dopamine reuptake transporter (DAT) binding values investigated by single photon computed tomography imaging (SPECT) with [\(^{123}\)I] N-\(\omega\)-fluoropropyl-2 \(\beta\)-carbomethoxy-3 \(\beta\)-(4-iodophenyl) tropane (FP-CIT). The intensity of tremor (i.e., the power of Electromyography [EMG] signals), but not its frequency, significantly increased during the task. In six subjects, tremor appeared selectively during the task. In a second part of the study, we retrospectively reviewed SPECT with FP-CIT data and confirmed the lack of correlation between dopaminergic loss and tremor by comparing DAT binding values of 82 PD subjects with bilateral tremor (n = 27), unilateral tremor (n = 22), and no tremor (n = 33). This study suggests a role of the LC in Parkinson tremor.

Rest tremor is generally regarded as the characteristic tremor which is associated with Parkinson’s disease (PD). However, some patients with PD also experience a postural tremor which may be unilateral or bilateral and may be more severe and disabling than their rest tremor. If other signs of PD are not yet present, a misdiagnosis of essential tremor (ET) is often made. The postural tremor of ET occurs immediately after the upper limbs are raised to a horizontal position, while the postural tremor of PD occurs after a latency of about 5 s and has the same frequency as the patient’s rest tremor.

Background: The possible relationship between essential tremor (ET) and Parkinson’s disease (PD) remains controversial since the first description of PD. However, there is increasing evidence suggesting the overlap between these two disorders. The aim of this review is to examine the relationship between PD and ET, focusing on clinical, epidemiologic, genetic, neuroimaging and neuropathological data, and the presence of cardinal symptoms of parkinsonism in ET. Methods: We conducted a PubMed search from 1966 until November 2011 on the relationship between ET and PD and the presence of postural tremor in PD patients, and the presence of rest tremor, rigidity and slowed movements in ET patients are reviewed. Results: Clinical series, follow-up studies of ET patients, and case-control and genetic epidemiological studies indicate that ET is associated with increased risk for PD. Some neuroimaging studies and neuropathological reports suggest association between the two diseases. ET patients have shown a high prevalence of rest tremor and at least 7 studies showed slowed movements (possibly related with cerebellar dysfunction and/or bradykinesia) in patients with ET. Conclusions: There is reasonable epidemiological and clinical evidence to support a link between ET and PD, although it is not clear what factors could predict the risk of developing PD in ET patients (or more rarely, of developing ET in PD patients). Future multicentric and multidisciplinary studies including epidemiological, clinical, neuroimaging, genetic and neuropathological assessment would be required to understand these associations., Tremor and Other Hyperkinetic Movements, Tremor and Other Hyperkinetic Movements

A novel fiber-optic accelerometer has been developed for the quantitative assessment of parkinsonian tremor at rest. The transducers is based on a fiber-optic sensing technique, that reduce some important drawbacks of biomedical applications, such as patient electrical safety and electromagnetic interference, and allows a non-invasive solution for monitoring of human movement, due to their limited mass. The sensing principle is based on the measurement of the transversal displacement of an emitting optical fiber cantilever due to the acceleration, conducted by means of a photodiode array: the detection of the light intensity profile makes the developed measurement system less sensitive to the light intensity variations independent from acceleration than intensity-based sensors. A dynamic calibration of the optical fiber accelerometer has been performed and a linear relationship between the lateral displacement of the fiber cantilever and acceleration has been experimentally evaluated. Moreover, a flat frequency response function between 3 Hz and 7 Hz (i.e. typical frequency range in which tremor at rest occurs in parkinsonian patients) and an high sensitivity in this frequency range (about 14 pixel/m.s-2) have been experimentally derived. These metrological features confirm that the proposed measurement system is particularly suitable for the quantitative assessment of parkinsonian tremor at rest.