Disease Tremor Research Articles

Vision-based estimation of MDS-UPDRS scores for quantifying Parkinson's disease tremor severity.

Parkinson's disease (PD) is a common neurodegenerative movement disorder among older individuals. As one of the typical symptoms of PD, tremor is a critical reference in the PD assessment. A widely accepted clinical approach to assessing tremors in PD is based on part III of the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS). However, expert assessment of tremor is a time-consuming and laborious process that poses considerable challenges to the medical evaluation of PD. In this paper, we proposed a novel model, Global Temporal-difference Shift Network (GTSN), to estimate the MDS-UPDRS score of PD tremors based on video. The PD tremor videos were scored according to the majority vote of multiple raters. We used Eulerian Video Magnification (EVM) pre-processing to enhance the representations of subtle PD tremors in the videos. To make the model better focus on the tremors in the video, we proposed a special temporal difference module, which stacks the current optical flow to the result of inter-frame difference. The prediction scores were obtained from the Residual Networks (ResNet) embedded with a novel module, the Global Shift Module (GSM), which allowed the features of the current segment to include the global segment features. We carried out independent experiments using PD tremor videos of different body parts based on the scoring content of the MDS-UPDRS. On a fairly large dataset, our method achieved an accuracy of 90.6% for hands with rest tremors, 85.9% for tremors in the leg, and 89.0% for the jaw. An accuracy of 84.9% was obtained for postural tremors. Our study demonstrated the effectiveness of computer-assisted assessment for PD tremors based on video analysis. The latest version of the code is available at https://github.com/199507284711/PD-GTSN.

Pharmacological Treatment of Tremor in Parkinson's Disease Revisited.

The pathophysiology of Parkinson's disease (PD) tremor remains incompletely understood and there is a lack of clinical trials specifically addressing its pharmacological treatment. Levodopa is the most efficacious drug for most patients and should be used as primary approach to control troublesome tremor. While the efficacy of oral dopamine agonists on PD tremor has been demonstrated in controlled trials, there is no evidence of greater antitremor efficacy compared to levodopa. The magnitude of the antitremor effect of anticholinergics is generally lower than that of levodopa. Due to their adverse effects, anticholinergics have a limited role in selected young and cognitively intact patients. Propranolol may improve resting and action tremor and may be considered as an adjunct in patients with insufficient tremor response to levodopa and this also applies to clozapine, despite its unfavorable adverse effect profile. Treating motor fluctuations with MAO-B and COMT inhibitors, dopamine agonists, amantadine, or on-demand treatments such as subcutaneous or sublingual apomorphine and inhaled levodopa as well as with continuous infusions of levodopa or apomorphine will improve off period tremor episodes. For patients with drug-refractory PD tremor despite levodopa optimization deep brain stimulation and focused ultrasound are first-line considerations. Surgery can also be highly effective for the treatment medication-refractory tremor in selected patients without motor fluctuations. The present review highlights the clinical essentials of parkinsonian tremor, critically examines available trial data on the effects of medication and surgical approaches and provides guidance for the choice of treatments to control PD tremor in clinical practice.

Analysis of Adaptive Algorithms Based on Least Mean Square Applied to Hand Tremor Suppression Control

The increase in life expectancy, according to the World Health Organization, is a fact, and with it rises the incidence of age-related neurodegenerative diseases. The most recurrent symptoms are those associated with tremors resulting from Parkinson’s disease (PD) or essential tremors (ETs). The main alternatives for the treatment of these patients are medication and surgical intervention, which sometimes have restrictions and side effects. Through computer simulations in Matlab software, this work investigates the performance of adaptive algorithms based on least mean squares (LMS) to suppress tremors in upper limbs, especially in the hands. The signals resulting from pathological hand tremors, related to PD, present components at frequencies that vary between 3 Hz and 6 Hz, with the more significant energy present in the fundamental and second harmonics, while physiological hand tremors, referred to ET, vary between 4 Hz and 12 Hz. We simulated and used these signals as reference signals in adaptive algorithms, filtered-x least mean square (Fx-LMS), filtered-x normalized least mean square (Fx-NLMS), and a hybrid Fx-LMS–NLMS purpose. Our results showed that the vibration control provided by the Fx-LMS–LMS algorithm is the most suitable for physiological tremors. For pathological tremors, we used a proposed algorithm with a filtered sinusoidal input signal, Fsinx-LMS, which presented the best results in this specific case.

Design and efficiency evaluation of a new wearable device for multi-degree suppression of hand pathological tremor

Sufferers of onset upper limb tremors find difficulty performing daily tasks due to rapid involuntary movements. Traditional treatments being offered help alleviate symptoms but are costly and can be invasive. Wearable technology advancements have introduced the applications of tremor suppression devices. A low-cost wearable bracelet was developed for sufferers of Parkinson’s disease and essential tremors to target rest and active tremors. Real-life measured tremor spectrums were used as input signals to design a dynamic vibration absorber. An innovative multiple-slot design allowed for multiple frequency suppression in the range of 3–8 Hz. A finite element analysis simulated the response of the upper limb with and without the bracelet. The results showed an overall suppression decreased tremors by up to 68% and targeted suppression decreased tremors by up to 98.2%.

Investigation of Phase Shifts Using AUC Diagrams: Application to Differential Diagnosis of Parkinson's Disease and Essential Tremor.

This study was motivated by the well-known problem of the differential diagnosis of Parkinson's disease and essential tremor using the phase shift between the tremor signals in the antagonist muscles of patients. Different phase shifts are typical for different diseases; however, it remains unclear how this parameter can be used for clinical diagnosis. Neurophysiological papers have reported different estimations of the accuracy of this parameter, which varies from insufficient to 100%. To address this issue, we developed special types of area under the ROC curve (AUC) diagrams and used them to analyze the phase shift. Different phase estimations, including the Hilbert instantaneous phase and the cross-wavelet spectrum mean phase, were applied. The results of the investigation of the clinical data revealed several regularities with opposite directions in the phase shift of the electromyographic signals in patients with Parkinson's disease and essential tremor. The detected regularities provide insights into the contradictory results reported in the literature. Moreover, the developed AUC diagrams show the potential for the investigation of neurodegenerative diseases related to the hyperkinetic movements of the extremities and the creation of high-accuracy methods of clinical diagnosis.

An Institutional Experience of Directional Deep Brain Stimulation and a Review of the Literature

IntroductionDirectional deep brain stimulation (dDBS) has been suggested to have a similar therapeutic effect when compared with the traditional omnidirectional DBS, but with an improved therapeutic window that yields optimized clinical effect owing to the ability to better direct, or “steer,” electric current. We present our single-center, retrospective analysis of our experience in the use of dDBS in patients with movement disorders and provide a review of the literature. Materials and MethodsWe identified all patients with Parkinson disease (PD) and essential tremor (ET) who received a dDBS system between 2018 and 2022 and retrospectively examined characteristics of their longitudinal treatment. A total of 70 leads were identified across 42 patients (28 PD, 14 ET). ResultsThree types of systems were implemented (single-segment activation, 45.2% of patients; multiple independent current control, 50.0%; and local field potential sensing-enabled, 4.7%). The subthalamic nucleus or globus pallidus internus was targeted in PD, and the ventral intermediate nucleus of the thalamus in ET. Across the entire cohort (n = 70 leads), at initial programming, 54.2% of leads (n = 38) were programmed using directional stimulation. At the most recent reprogramming, 58.6% of leads (n = 41) implemented directionality. In patients with PD, the average decrease in levodopa-equivalent daily dose at six months after implantation was 35.4% ± 39.2%. Despite the ability to steer current to relieve stimulation-induced side effects, ten leads in six patients required surgical revision owing to electrode malposition. ConclusionsWe show wide adaptability and implementation of directional stimulation, adding to the growing compendium of real-world uses of dDBS therapy. We used directionality to improve clinical response in both patients with PD and patients with ET and found that its programming flexibility was used at high rates long after implantation and initial programming. In patients with PD, dDBS led to a significant reduction in dopaminergic medication, suggesting sustained clinical improvement. Nonetheless, accurate surgical placement remains necessary to ensure optimal clinical outcomes.

Using of MRI-guided focused ultrasound treatment for Parkinson’s disease tremor. Clinical case and literature review

MRI-guided high-intensity focused ultrasound (MRgFUS) is a new emerging and promising procedure applied in a wide range of clinical fi elds in modern medicine. This innovative treatment method follows is an important step towards the ideal surgery of the future: non-invasive, targeted, safe, controlled, eff ective and ambulatory. Randomized studies show high effi cacy in the treatment of tremor for Parkinson disease and essential tremor. Safety is also having similar profi le with other surgical procedures and has a mostly transient character of complications. Such advantages as a non-invasive treatment, controlled eff ect and the safety profi le of the procedure made it popular in the treatment of movement disorders. This article demonstrates a clinical case of the fi rst using of MRgFUS for the treatment of Parkinson’s disease tremor at the Federal Center for Brain Research and Neurotechnologies of the Federal Medical and Biological Agency of Russia in Moscow. The 54-year-old patient with Parkinson disease, 2 Hoehn–Yahr, admitted to our hospital. Severe tremor of right upper extremity impaired his life. Neurosurgical procedure was considered due to medication failed. Patient underwent focused ultrasound thalamotomy with totally tremor relief. No additional neurological impairment was noted, only bradykinesia and rigidity were improved. Patient discharged on 3rd day after the procedure.Conclusions. MRgFUS is an innovative surgical procedure. Advantages of these methods such as non-invasive manner, controlled, safety allowed to be priority procedure for patients with unilateral tremor.

A Wearable Multi-segment Upper Limb Tremor Assessment System for Differential Diagnosis of Parkinson's Disease versus Essential Tremor.

Upper limb tremor is a prominent symptom of both Parkinson's disease and essential tremor. Its kinematic parameters overlap substantially for these two pathological conditions, thus leading to high rate of misdiagnosis, especially for community doctors. Several groups have proposed various methods for improving differential diagnosis. These prior studies have attempted to identify better kinematic parameters, however they have mainly focused on single limb features including tremor intensity, tremor frequency, and tremor variability. In this paper, we propose a wearable system for multi-segment assessment of upper limb tremor and differential diagnosis of Parkinson's disease versus essential tremor. The proposed system collected tremor data from both wrist and fingers simultaneously. From this data, we extracted multi-segment features in the form of phase relationships between limb segments. Using support vector machine classifiers, we then performed differential diagnosis from the extracted features. We evaluated the performance of the proposed system on 19 Parkinson's disease patients and 12 essential tremor patients. Moreover, we also assessed the performance cost associated with reducing task load and sensor array size. The proposed system reached perfect accuracy in leave-one-out cross validation. Task reduction and sensor array reduction were associated with penalties of 2% and 9-10% respectively. The results demonstrated that the proposed system could be simplified for clinical applications, and successfully applied to the differential diagnosis of Parkinson's disease versus essential tremor in real-world setting.

Model Predictive Control for Tremor Suppressing Exoskeleton

This paper focuses on the application of model-based predictive control (MPC) for a full wrist exoskeleton designed for the alleviation of tremors in patients suffering from Parkinson's Disease and Essential Tremor. The main motivation for using MPC here relies on its ability to incorporate state and input constraints, which are crucial for the user's safety. The forearm-exoskeleton model is successively linearized at each time sample to obtain a linear state space model. The optimal input is then generated by minimizing a convex quadratic cost function. Finally, simulation cases are provided to demonstrate the effectiveness of the control scheme.

Unveiling the Impact of Outpatient Physiotherapy on Specific Motor Symptoms in Parkinson's Disease: A Prospective Cohort Study.

Understanding how outpatient physiotherapy impacts on specific motor symptoms in Parkinson's disease (PD) is important for multidisciplinary care, but these points have not been clarified. We investigated the impact of outpatient physiotherapy on individual motor symptoms in PD patients. Fifty-five PD patients participated in the prospective cohort study, which examined the changes in motor symptoms after 90 min of outpatient physiotherapy program (1×/week for 10 weeks) and at 3 months follow-up. Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) motor score and tremor, rigidity, bradykinesia, and axial scores were assessed and compared pre-intervention, post-intervention, and at follow-up. Significant level was set at 0.05. Their MDS-UPDRS motor score and axial score significantly decreased post-intervention and at the follow-up. In the analysis differentiating effects based on the severity of motor symptoms according to the MDS-UPDRS motor score, only the moderate-severe group showed significant decreases in their MDS-UPDRS motor score, bradykinesia, and axial scores post-intervention, as well as in their MDS-UPDRS motor score, rigidity, bradykinesia, and axial scores at the follow-up. These findings suggest the outpatient physiotherapy might provide benefits, particularly in managing axial symptoms and bradykinesia, for community dwelling PD patients with moderate-severe motor symptoms within a multidisciplinary care framework.

Locus coeruleus and substantia nigra neuromelanin magnetic resonance imaging differentiates Parkinson’s disease and essential tremor

BackgroundDifferential diagnosis of essential tremor (ET) and Parkinson’s disease (PD) can still be a challenge in clinical practice. These two tremor disorders may have different pathogenesis related to the substantia nigra (SN) and locus coeruleus (LC). Characterizing neuromelanin (NM) in these structures may help improve the differential diagnosis. MethodsForty-three subjects with tremor-dominant PD (PDTD), 31 subjects with ET, and 30 age- and sex-matched healthy controls were included. All subjects were scanned with NM magnetic resonance imaging (NM-MRI). NM volume and contrast measures for the SN and contrast for the LC were evaluated. Logistic regression was used to calculate predicted probabilities by using the combination of SN and LC NM measures. The discriminative power of the NM measures in detecting subjects with PDTD from ET was assessed with a receiver operative characteristic curve, and the area under the curve (AUC) was calculated. ResultsThe NM contrast-to-noise ratio (CNR) of the LC, the NM volume, and CNR of the SN on the right and left sides were significantly lower in PDTD subjects than in ET subjects or healthy controls (all P < 0.05). Furthermore, when combining the best model constructed from the NM measures, the AUC reached 0.92 in differentiating PDTD from ET. ConclusionThe NM volume and contrast measures of the SN and contrast for the LC provided a new perspective on the differential diagnosis of PDTD and ET, and the investigation of the underlying pathophysiology.

Neuromelanin-Sensitive Magnetic Resonance Imaging as a Measure for Differential Diagnosis of Essential Tremor and Parkinson's Disease.

We sought to evaluate whether the neuromelanin-sensitive magnetic resonance imaging (NM-MRI) features of the substantia nigra (SN) have utility in the differential diagnosis of Parkinson's disease (PD) and essential tremor (ET). This study enrolled 23 patients with PD, 20 patients with ET, and 18 healthy participants. All subjects underwent clinical examination, motor and cognitive assessments, and NM-MRI scans. The area and contrast-to-noise ratio (CNR) values of SN were defined according to NM-MRI images. Then, receiver operating characteristic (ROC) analysis was conducted to characterize the diagnostic power of the SN area and CNR values of SN. Compared with ET and control groups, the PD group showed a significant reduction of the area of SN (P = 0.003, PD vs. ET; P = 0.001, PD vs. control) and in the SN to midbrain area ratio in the same layer (P = 0.006, PD vs. ET; P = 0.005, PD vs. control). The SN area had a sensitivity of 65% and a specificity of 87% for distinguishing ET from PD, with an area under the curve (AUC) of 0.7630 and a Youden index of 0.5200, whereas the ratio of the SN area to midbrain area in the same layer had a sensitivity of 60% and a specificity of 87% for distinguishing ET from PD, with an AUC of 0.7478 and a Youden index of 0.4700. Compared with the ET group, the mean CNR value of the SN and the respective CNR values of the three subregions were all weakened in the PD group, and only the CNR in the middle part was significantly different from the control group (P = 0.006). The sensitivity of the CNR value of the middle part of the SN for differentiating ET from PD was 65%, the specificity was 87%, the AUC was 0.7500, and the Youden index was 0.5200.Based on our findings, we conclude that NM-MRI can improve diagnostic accuracy in PD and can be used as a specific and sensitive potential diagnostic biomarker for PD.

Digitising tremor

The nervous system speaks a digital language. A heathy nervous system orchestrates a vast array of action potentials to produce a repertoire of voluntary movements. Neurological diseases such as parkinson's disease and essential tremor (ET), however, disrupt the execution of smooth voluntary movements and hinder the performance of even simple tasks, like holding a cup of coffee. ET, the most common movement disorder, affects an estimated 5% of people aged 60 years and older globally. Although the complete set of neurological mechanisms that cause ET are yet to be elucidated, oscillatory signalling within the ventral intermediate nucleus of the thalamus (VIM) has a key role. Two insights are opening the door to developing improved diagnostics and therapies for people with ET.

Retracted: Task-Oriented Intelligent Solution to Measure Parkinson's Disease Tremor Severity.

[This retracts the article DOI: 10.1155/2021/9624386.].

A Review of Techniques Used to Suppress Tremor

The most frequent movement disorder is Tremor, which has an increased incidence and prevalence in people over 65 who have Parkinson's disease or essential tremors. Although not life-threatening, it prevents patients from performing their daily activities. An overview of different types of tremors and their treatment in medical and surgical views are discussed in this paper with a review of the stimulation nerves and muscles technique. Then a look at tremor detection and measurement methods are considered with a review of the medical devices' mechanism of action that is placed as a substitute treatment for patients that have a low response to medications and surgical treatment to provide effective and safe tremor suppression.

Noninvasive neuroimaging provides evidence for deterioration of the glymphatic system in Parkinson's disease relative to essential tremor

IntroductionGrowing evidence has demonstrated dysfunction of the glymphatic system in α-synucleinopathy and related diseases. In this study, we aimed to use diffusion tensor image analysis along the perivascular space (DTI-ALPS) and MRI-visible enlarged perivascular spaces (EPVS) to evaluate glymphatic system function quantitatively and qualitatively and its relationship to clinical scores of disease severity in Parkinson's disease (PD) and essential tremor (ET). MethodsOverall, 124 patients with PD, 74 with ET, and 106 healthy controls (HC) were enrolled. Two trained neurologists performed quantitative calculations of ALPS on DTI and visual ratings of EPVS on T2-weighted images in the centrum semiovale (CSO), basal ganglia (BG), midbrain, and cerebellum. ResultsThe ALPS index was lower in patients with PD than in patients with ET (p < 0.001) and HC (p < 0.001). Similarly, patients with PD showed a more severe EPVS burden in the CSO, BG, and midbrain compared to ET and HC. Moreover, the ALPS index was negatively correlated with disease severity in the PD subgroups; however, it did not differ within the ET subgroup. No differences in ALPS or EPVS were observed between the ET and HC groups. ConclusionIn conclusion, DTI-ALPS and EPVS both provide neuroimaging evidence of glymphatic system dysfunction in PD, which further supports that PD is an α-synucleinopathy disease, while ET is a cerebellar dysfunction-related disease.

IMPACT OF VIBRATION ON TREMOR IN OLDER ADULTS WITH PARKINSON’S DISEASE

Abstract This was a randomized trial to explore the safety and efficacy of the RMBand (Resonate Forward LLC, Delaware) device to alleviate Parkinson’s Disease (PD) tremors. The RMBand applies vibration to the proximal arm and was worn on the side of tremor dominance. Thirty subjects with PD and associated tremors were randomized to receive high vs. low-frequency vibration. Tremor assessments occurred for 20 minutes before, during 20 minutes of continuous vibration, and for 20 minutes immediately post-vibration in a single 60-minute session. Assessments (MDS-UPDRS part 3 and FTM tremor scale) were performed during each of the 3 phases by blinded raters. A quantitative assessment of tremor was performed throughout the session using wearable sensors on the distal arms. Linear mixed models were used for group comparisons. No significant difference was observed between the high and low dose groups in the MDS-UPDRS part 3 or FTM tremor scale (p=0.83 and 0.48 respectively), which may be due to the crude nature of these scales. Quantitative wearable sensor data were used to assess total time with tremors during the pre-vibration, vibration, and post-vibration periods. Time with tremor during the pre-vibration period was significantly greater than that during and post-vibration (p&amp;lt; 0.0001) for both dose groups, suggesting that vibration therapy applied to the proximal arm may suppress PD tremor. No significant adverse events related to vibration therapy occurred. In conclusion, the RMBand appears safe and possibly effective for suppressing PD tremor. Further study is warranted.

Analyses of correct responses and errors on measures of verbal fluency among Parkinson’s disease and essential tremor patients

Objective: Parkinson’s disease (PD) and essential tremor (ET) involve neuroanatomical circuitry that impact frontal lobe functioning, via the striatum and cerebellum, respectively. The aim of this exploratory study was to investigate quantitative and qualitative performance between and within these groups on measures of verbal fluency. Method: Sixty-three PD and 53 ET patients completed neuropsychological testing. Linear regression models with robust variance estimation compared verbal fluency performance between groups related to correct responses and errors. Paired t-tests investigated within group error rates. Results: PD patients gave more correct responses for phonological ( β ̂ =5.3, p=.01) and category fluency ( β ̂ =4.1, p=.01) than ET patients; however, when processing speed was added as a covariate, this attenuated performance on both measures and only phonological fluency remained significant ( β ̂ =4.0, p=.04). There were no statistical differences in error scores between groups. Error rates within groups suggested that PD patients had higher error rates in total errors and perseveration errors on phonological fluency (M = 2.6, p=.00; M = 1.6, p=.00) and higher total errors and set-loss error rates on category switching (M = 5.1, p<.001; M = 4.1, p<.001). ET patients had higher error rate with relation to total errors and set-loss errors on phonological fluency (M = 2.5, p=.00; M = 1.5, p=.02) and category switching (M = 3.9, p=,00; M = 3.9, p<.001). Conclusions: PD patients performed better than ET patients on phonological fluency. PD patients appear to make more perseveration errors on phonological fluency, while ET patients made more set-loss errors. Implications for frontal lobe dysfunction and clinical impact are discussed.

Zonisamide add-on in tremor-dominant Parkinson's disease- A randomized controlled clinical trial

Introductionand objective: Tremor is a disabling symptom of PD that usually responds poorly to available standard pharmacological agents. This study aimed to assess the effect of Zonisamide 25 mg on tremor in tremor-dominant PD patients as compared to placebo. MethodsThis was a randomized, placebo-controlled, double-blind study. Parkinson's disease patients were allocated either to the intervention group (standard treatment along with Zonisamide 25 mg add-on) or the placebo group (standard treatment along with placebo). Baseline Unified Parkinson's Disease Rating Scale (UPDRS) and Tremor Research Group Essential Tremor Rating Scale (TETRAS) scores, as well as accelerometric tremor analysis were done and follow-up assessments of the same were done after 12 weeks of intervention. Percentage change from baseline in the UPDRS tremor score was the primary outcome whereas percentage change from baseline of total UPDRS score, UPDRS rigidity and bradykinesia scores, TETRAS score, and accelerometric tremor analysis values were the secondary outcomes. ResultsThere was no significant difference in the percentage change from baseline UPDRS tremor scores between the two groups (placebo: 8.33 [-19.89–23.86] vs drug: 26.14 [-35.58 to −16.07], p-value: 0.164, CI: 0.157–0.171). Best-case analysis for missing values showed a significant improvement in the drug group, compared to the placebo group (p-value: < 0.001, CI: <0.001 - <0.001). ConclusionZonisamide at a dose of 25 mg per day did not improve tremor in tremor-dominant PD patients, however, a positive trend was seen as compared to Placebo in the UPDRS tremor score. Larger studies are required to confirm this finding.

Differential contributions of depression, apathy, and anxiety to neuropsychological performance in Parkinson’s disease versus essential tremor

ABSTRACT Introduction Mood symptoms are common features of Parkinson’s disease (PD) and essential tremor (ET) and have been linked to worse cognition. The goals of the present study were to compare the severity of anxiety, apathy, and depressive symptoms in PD, ET, and healthy controls (HC) and to examine differential relationships between mood and cognition. Method Older adults with idiopathic PD (N = 448), ET (N = 128), or HC (N = 136) completed a multi-domain neuropsychological assessment consisting of memory, executive function, and attention/working memory domains. Participants also completed self-reported mood measures. Between-group differences in mood and cognition were assessed, and hierarchical regression models were conducted to examine relationships between mood and cognition in each group. Results Relative to the HC group, the PD and ET groups reported more mood symptoms and scored lower across all cognitive measures. There were no differences between the two movement disorder groups. Mood variables explained 3.9–13.7% of the total variance in cognitive domains, varying by disease group. For PD, apathy was the only unique predictor of executive function (β = −.114, p = .05), and trait anxiety was the only unique predictor of attention/working memory (β = −.188, p < .05). For ET, there were no unique predictors, though the overall models significantly predicted performance in the executive function and attention/working memory domains. Conclusions In a large cohort of ET and PD, we observed that the two groups had similar self-reported mood symptoms. Mood symptoms were differentially associated with cognition in PD versus ET. In PD, increased apathy was associated with worse executive function and higher trait anxiety predicted worse attention/working memory. For ET, there were no unique predictors, though the overall mood symptom severity was related to cognition. Our study highlights the importance of considering the relationship between mood and neuropsychological performance in individuals with movement disorders.