Bradykinesia and Its Progression Are Related to Interhemispheric Beta Coherence.

OBJECTIVE: Bradykinesia is the major cardinal motor sign of Parkinson disease (PD), but its neural underpinnings are unclear. The goal of this study was to examine whether changes in bradykinesia following long-term subthalamic nucleus (STN) deep brain stimulation (DBS) are linked to local STN beta (13-30 Hz) dynamics or a wider bilateral network dysfunction. METHODS: Twenty-one individuals with PD implanted with sensing neurostimulators (Activa® PC + S, Medtronic, PLC) in the STN participated in a longitudinal 'washout' therapy study every three to 6 months for an average of 3 years. At each visit, participants were withdrawn from medication (12/24/48 hours) and had DBS turned off (>60 minutes) before completing a repetitive wrist-flexion extension task, a validated quantitative assessment of bradykinesia, while local field potentials were recorded. Local STN beta dynamics were investigated via beta power and burst duration, while interhemispheric beta synchrony was assessed with STN-STN beta coherence. RESULTS: Higher interhemispheric STN beta coherence, but not contralateral beta power or burst duration, was significantly associated with worse bradykinesia. Bradykinesia worsened off therapy over time. Interhemispheric STN-STN beta coherence also increased over time, whereas beta power and burst duration remained stable. The observed change in bradykinesia was related to the change in interhemispheric beta coherence, with greater increases in synchrony associated with further worsening of bradykinesia. INTERPRETATION: Together, these findings implicate interhemispheric beta synchrony as a neural correlate of the progression of bradykinesia following chronic STN DBS. This could imply the existence of a pathological bilateral network contributing to bradykinesia in PD. ANN NEUROL 2023;93:1029-1039.

Bradykinesia in Neurodegenerative Disorders: A Blinded Video Analysis of Pathology-Proven Cases.

BACKGROUND: Bradykinesia is a cardinal feature in parkinsonisms. No study has assessed the differential features of bradykinesia in patients with pathology-proven synucleinopathies and tauopathies. OBJECTIVE: We examined whether bradykinesia features (speed, amplitude, rhythm, and sequence effect) may differ between pathology-proven synucleinopathies and tauopathies. METHODS: Forty-two cases who underwent autopsy were included and divided into synucleinopathies (Parkinson's disease and dementia with Lewy bodies) and tauopathies (progressive supranuclear palsy). Two raters blinded to the diagnosis retrospectively scored the Movement Disorders Society-Unified Parkinson's Disease Rating Scale Part III and Modified Bradykinesia Rating Scale on standardized videotaped neurological examinations. Bradykinesia scores were compared using the Mann-Whitney test and logistic regression models to adjust for disease duration. RESULTS: Demographic and clinical parameters were similar between synucleinopathies and tauopathies. There were no differences between speed, amplitude, rhythm, and sequence effect in synucleinopathies and tauopathies in unadjusted comparisons and adjusted models (all P > 0.05). CONCLUSIONS: Clinical bradykinesia features do not distinguish the underlying neuropathology in neurodegenerative parkinsonisms. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Modulation of beta bursts in subthalamic sensorimotor circuits predicts improvement in bradykinesia.

No biomarker of Parkinson's disease exists that allows clinicians to adjust chronic therapy, either medication or deep brain stimulation, with real-time feedback. Consequently, clinicians rely on time-intensive, empirical, and subjective clinical assessments of motor behaviour and adverse events to adjust therapies. Accumulating evidence suggests that hypokinetic aspects of Parkinson's disease and their improvement with therapy are related to pathological neural activity in the beta band (beta oscillopathy) in the subthalamic nucleus. Additionally, effectiveness of deep brain stimulation may depend on modulation of the dorsolateral sensorimotor region of the subthalamic nucleus, which is the primary site of this beta oscillopathy. Despite the feasibility of utilizing this information to provide integrated, biomarker-driven precise deep brain stimulation, these measures have not been brought together in awake freely moving individuals. We sought to directly test whether stimulation-related improvements in bradykinesia were contingent on reduction of beta power and burst durations, and/or the volume of the sensorimotor subthalamic nucleus that was modulated. We recorded synchronized local field potentials and kinematic data in 16 subthalamic nuclei of individuals with Parkinson's disease chronically implanted with neurostimulators during a repetitive wrist-flexion extension task, while administering randomized different intensities of high frequency stimulation. Increased intensities of deep brain stimulation improved movement velocity and were associated with an intensity-dependent reduction in beta power and mean burst duration, measured during movement. The degree of reduction in this beta oscillopathy was associated with the improvement in movement velocity. Moreover, the reduction in beta power and beta burst durations was dependent on the theoretical degree of tissue modulated in the sensorimotor region of the subthalamic nucleus. Finally, the degree of attenuation of both beta power and beta burst durations, together with the degree of overlap of stimulation with the sensorimotor subthalamic nucleus significantly explained the stimulation-related improvement in movement velocity. The above results provide direct evidence that subthalamic nucleus deep brain stimulation-related improvements in bradykinesia are related to the reduction in beta oscillopathy within the sensorimotor region. With the advent of sensing neurostimulators, this beta oscillopathy combined with lead location could be used as a marker for real-time feedback to adjust clinical settings or to drive closed-loop deep brain stimulation in freely moving individuals with Parkinson's disease.

Evolving concepts on bradykinesia.

Bradykinesia is one of the cardinal motor symptoms of Parkinson's disease and other parkinsonisms. The various clinical aspects related to bradykinesia and the pathophysiological mechanisms underlying bradykinesia are, however, still unclear. In this article, we review clinical and experimental studies on bradykinesia performed in patients with Parkinson's disease and atypical parkinsonism. We also review studies on animal experiments dealing with pathophysiological aspects of the parkinsonian state. In Parkinson's disease, bradykinesia is characterized by slowness, the reduced amplitude of movement, and sequence effect. These features are also present in atypical parkinsonisms, but the sequence effect is not common. Levodopa therapy improves bradykinesia, but treatment variably affects the bradykinesia features and does not significantly modify the sequence effect. Findings from animal and patients demonstrate the role of the basal ganglia and other interconnected structures, such as the primary motor cortex and cerebellum, as well as the contribution of abnormal sensorimotor processing. Bradykinesia should be interpreted as arising from network dysfunction. A better understanding of bradykinesia pathophysiology will serve as the new starting point for clinical and experimental purposes.

Listen to your patient: A fiddler's tale.

A professional violinist reported increasing difficulties playing the violin. He executed the initial half of the musical piece well, but produced an increasing number of mistakes during the second half. Neurological examination was remarkable for bradykinesia and tremor. Formal acoustic analysis of finger taps and pronation-supination showed a decrement in sound intensity and number of taps over time. Oscillations in performance correlated with a parkinsonian tremor. We interpret these findings as the audible equivalent of bradykinesia and tremor. Listening to bradykinesia and quantifying its decrement using acoustic analysis may offer a simple, objective, and reliable supplement to the neurological examination. Ann Neurol 2018;84:931-933.

Combined Effects of Hypokinesia and Ambient Temperature on Heart Remodeling in Normotensive and Hypertensive Rats.

We studied the effect of hypokinesia combined with cold exposure on morphological parameters of the heart in Wistar-Kyoto rats and rats with spontaneous genetically determined hypertension (SHR). The pathological processes developing in the heart of white laboratory rats significantly affected cardiac function and manifested in the deterioration of the morphological structure of the heart: reduction of heart weight, thinning of the free wall of the left ventricle. These changes indicate transition to a lower energy level of functioning. At the same time, hypertrophy of the right free wall develops in both rat lines. Combined effect of hypokinesia and cold is probably a factor indirectly promoting the development of pulmonary heart.

A systematic review of mobility/immobility in thromboembolism risk assessment models for hospitalized patients.

Hospitalized patients are at risk of venous thromboembolism (VTE) and prophylaxis is often suboptimal due to difficulty in identifying at-risk patients. Simple and validated risk-assessment models (RAMs) are available to assist clinicians in identifying patients who have a high risk for developing VTE. Despite the well-documented association of immobility with increased risk of thrombosis, immobility is not consistently defined in clinical studies. We conducted a systematic review of published VTE RAMs and used objective criteria to determine how the term immobility is defined in RAMs. We identified 17 RAMs with six being externally validated. The concept of immobility is vaguely described in different RAMs, impacting the validity of these models in clinical practice. The wide variability in defining mobility in RAMs precluded its accurate clinical application, further limiting generalization of published RAMs. Externally validated RAMs with clearly defined qualitative or quantitative terms of immobility are needed to assess VTE risk in real-time at the point-of-care.

Regulation of parkinsonian motor behaviours by optogenetic control of basal ganglia circuitry.

Neural circuits of the basal ganglia are critical for motor planning and action selection. Two parallel basal ganglia pathways have been described, and have been proposed to exert opposing influences on motor function. According to this classical model, activation of the 'direct' pathway facilitates movement and activation of the 'indirect' pathway inhibits movement. However, more recent anatomical and functional evidence has called into question the validity of this hypothesis. Because this model has never been empirically tested, the specific function of these circuits in behaving animals remains unknown. Here we report direct activation of basal ganglia circuitry in vivo, using optogenetic control of direct- and indirect-pathway medium spiny projection neurons (MSNs), achieved through Cre-dependent viral expression of channelrhodopsin-2 in the striatum of bacterial artificial chromosome transgenic mice expressing Cre recombinase under control of regulatory elements for the dopamine D1 or D2 receptor. Bilateral excitation of indirect-pathway MSNs elicited a parkinsonian state, distinguished by increased freezing, bradykinesia and decreased locomotor initiations. In contrast, activation of direct-pathway MSNs reduced freezing and increased locomotion. In a mouse model of Parkinson's disease, direct-pathway activation completely rescued deficits in freezing, bradykinesia and locomotor initiation. Taken together, our findings establish a critical role for basal ganglia circuitry in the bidirectional regulation of motor behaviour and indicate that modulation of direct-pathway circuitry may represent an effective therapeutic strategy for ameliorating parkinsonian motor deficits.

Infection as cause of immobility and occurrence of venous thromboembolism: analysis of 1635 medical cases from the RIETE registry.

Several risk assessment models include infection and immobility among the items to be considered for venous thromboembolism (VTE) prevention. However, information on patients with infection leading to immobility and developing VTE are limited, as well as on the role of specific types of infection. Data were collected from the worldwide RIETE registry, including patients with symptomatic objectively confirmed VTE, and followed-up for at least 3 months. The overall population of RIETE at June 2013 (n = 47,390) was considered. Acute infection leading to immobility was reported in 3.9 % of non-surgical patients. Compared with patients immobilized due to dementia, patients with infection had a shorter duration of immobilization prior to VTE (less than 4 weeks in 94.2 vs. 25.9 % of cases; p < 0.001). During the 3-month follow-up, VTE patients with infection versus those with dementia had a lower rate of fatal bleeding (0.5 vs. 1.1 %; p < 0.05) or fatal PE (1.7 vs. 3.5 %; p < 0.01). Patients with respiratory tract infections had more likely PE as initial VTE presentation than other types of infection (62.3 vs. 37.7 %; p < 0.001). Significantly more patients with pneumonia than those with other respiratory infections had received VTE prophylaxis (50.2 vs. 30.6 %; p < 0.001). Following VTE, patients with sepsis showed a significantly higher risk of fatal bleeding. Based on our real-world data, infection seems to contribute to the pathogenesis of VTE by accelerating the effects of immobility. Its role as VTE risk factor probably deserves further attention and specific assessment in order to optimize VTE prophylaxis and treatment.

Parkinson's Disease Case Ascertainment in the EPIC Cohort: The NeuroEPIC4PD Study.

BACKGROUND/AIMS: Large epidemiological prospective studies represent an important opportunity for investigating risk factors for rare diseases such as Parkinson's disease (PD). Here we describe the procedures we used for ascertaining PD cases in the EPIC (European Prospective Investigation into Cancer and Nutrition) study. METHODS: The following three-phase procedure was used: (1) elaboration of a NeuroEPIC4PD template for clinical data collection, (2) identification of all potential PD cases via record linkage and (3) validation of the diagnosis through clinical record revision, in a population of 220,494 subjects recruited in 7 European countries. All cases were labelled with the NeuroEPIC4PD diagnoses of 'definite', 'very likely', 'probable', or 'possible' PD. RESULTS: A total of 881 PD cases were identified, with over 2,741,780 person-years of follow-up (199 definite, 275 very likely, 146 probable, and 261 possible). Of these, 734 were incident cases. The mean age at diagnosis was 67.9 years (SD 9.2) and 458 patients (52.0%) were men. Bradykinesia was the most frequent presenting motor sign (76.5%). Tremor-dominant and akinetic rigid forms of PD were the most common types of PD. A total of 289 patients (32.8%) were dead at the time of the last follow-up. CONCLUSIONS: This exercise proved that it is feasible to ascertain PD in large population-based cohort studies and offers a potential framework to be replicated in similar studies.

Automatic Spiral Analysis for Objective Assessment of Motor Symptoms in Parkinson's Disease.

A challenge for the clinical management of advanced Parkinson's disease (PD) patients is the emergence of fluctuations in motor performance, which represents a significant source of disability during activities of daily living of the patients. There is a lack of objective measurement of treatment effects for in-clinic and at-home use that can provide an overview of the treatment response. The objective of this paper was to develop a method for objective quantification of advanced PD motor symptoms related to off episodes and peak dose dyskinesia, using spiral data gathered by a touch screen telemetry device. More specifically, the aim was to objectively characterize motor symptoms (bradykinesia and dyskinesia), to help in automating the process of visual interpretation of movement anomalies in spirals as rated by movement disorder specialists. Digitized upper limb movement data of 65 advanced PD patients and 10 healthy (HE) subjects were recorded as they performed spiral drawing tasks on a touch screen device in their home environment settings. Several spatiotemporal features were extracted from the time series and used as inputs to machine learning methods. The methods were validated against ratings on animated spirals scored by four movement disorder specialists who visually assessed a set of kinematic features and the motor symptom. The ability of the method to discriminate between PD patients and HE subjects and the test-retest reliability of the computed scores were also evaluated. Computed scores correlated well with mean visual ratings of individual kinematic features. The best performing classifier (Multilayer Perceptron) classified the motor symptom (bradykinesia or dyskinesia) with an accuracy of 84% and area under the receiver operating characteristics curve of 0.86 in relation to visual classifications of the raters. In addition, the method provided high discriminating power when distinguishing between PD patients and HE subjects as well as had good test-retest reliability. This study demonstrated the potential of using digital spiral analysis for objective quantification of PD-specific and/or treatment-induced motor symptoms.

Symptom Analysis of Early Parkinson's Disease and its Correlation with High Sensitivity C-reactive Protein.

Parkinson's disease is a debilitating neurodegenerative disease for which there is no cure. It is characterized by bradykinesia, resting tremor, rigidity and postural instability, due to impairment of function of the basal ganglia which is involved in the coordination of body movement. Neuro-inflammation is pathogenesis of development in early Parkinson's disease. High-sensitivity C-reactive protein level is a useful non-specific biochemical marker of inflammation. Objective of this study was to analyze the symptoms of Parkinson disease and it's correlation with high sensitive CRP. Seventy-six Parkinson's disease patients were enrolled in this Cross-sectional observational study that was attended in the Department of Neurology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Bangladesh from September 2014 to March 2016. Analysis of the symptoms of Parkinson disease and it's correlation with high sensitive CRP were done among these patients. This study was performed on 76 Parkinson disease patients with presented early with symptoms. a positive and highly significant correlation were seen in between duration of tremor and High sensitivity CRP (r=0.430, p<0.001) and between duration of bradykinesia and High sensitivity CRP (r=0.426, p<0.001) which indicate increase duration causes increase level of high-sensitivity C-reactive protein value. The neuro-inflammation plays a significant role in the pathogenesis of symptoms development in early Parkinson's disease.

Better global and cognitive functioning in choreatic versus hypokinetic-rigid Huntington's disease.

BACKGROUND: Understanding the relation between predominantly choreatic and hypokinetic-rigid motor subtypes and cognitive and general functioning may contribute to knowledge about different motor phenotypes in Huntington's disease. METHODS: In the European Huntington's Disease Network Registry study, 1882 subjects were classified as being predominantly choreatic (n=528) or hypokinetic-rigid (n=432), according to their scores on items of the total motor score a priori labeled as choreatic or hypokinetic-rigid; the other 922 patients were of a mixed type. The relationship between motor type and cognitive (verbal fluency, symbol digit modalities, Stroop color, word and interference tests) and functional (total functional capacity) capacity was investigated using multiple linear regression. RESULTS: Motor subtype contributed significantly to the total functional capacity score (partial r(2) : 7.8%; P<.001) and to the 5 cognitive scores (partial r(2) ranged from 2.0% to 8.4%; all P<.001). CONCLUSIONS: Patients with a predominantly choreatic motor phenotype performing better in all areas than patients with a hypokinetic-rigid motor phenotype.

Comparing kinematic changes between a finger-tapping task and unconstrained finger flexion-extension task in patients with Parkinson's disease.

Repetitive finger tapping is a well-established clinical test for the evaluation of parkinsonian bradykinesia, but few studies have investigated other finger movement modalities. We compared the kinematic changes (movement rate and amplitude) and response to levodopa during a conventional index finger-thumb-tapping task and an unconstrained index finger flexion-extension task performed at maximal voluntary rate (MVR) for 20 s in 11 individuals with levodopa-responsive Parkinson's disease (OFF and ON) and 10 healthy age-matched controls. Between-task comparisons showed that for all conditions, the initial movement rate was greater for the unconstrained flexion-extension task than the tapping task. Movement rate in the OFF state was slower than in controls for both tasks and normalized in the ON state. The movement amplitude was also reduced for both tasks in OFF and increased in the ON state but did not reach control levels. The rate and amplitude of movement declined significantly for both tasks under all conditions (OFF/ON and controls). The time course of rate decline was comparable for both tasks and was similar in OFF/ON and controls, whereas the tapping task was associated with a greater decline in MA, both in controls and ON, but not OFF. The findings indicate that both finger movement tasks show similar kinematic changes during a 20-s sustained MVR, but that movement amplitude is less well sustained during the tapping task than the unconstrained finger movement task. Both movement rate and amplitude improved with levodopa; however, movement rate was more levodopa responsive than amplitude.

Does motor dysfunction after cerebral infarction impede the development of angina symptoms? A comparison of coronary angiographic findings in patients with and without prior cerebral infarction.

Previous studies based on coronary angiography or computed tomography coronary angiography have demonstrated a high prevalence of coronary stenosis in patients with cerebral infarction and no prior history of coronary artery disease (CAD). The purpose of the present study was to compare the coronary angiographic findings of patients with prior cerebral infarction with those of patients with no prior cerebral infarction. Consecutive patients (n = 126) who underwent a first coronary angiography for suspected CAD but had no prior history of CAD were classified into 2 groups, those with a clinical history of cerebral infarction (cerebral infarction group) and those without a clinical history of cerebral infarction (noncerebral infarction group). The incidences of diabetes mellitus, peripheral artery disease, coronary stenosis, and multivessel disease were significantly higher in the cerebral infarction group than in the noncerebral infarction group. Multiple logistic regression analysis relating to coronary stenosis identifi ed prior cerebral infarction (P = 0.0027, odds ratio = 4.414) and diabetes mellitus (P = 0.0446, odds ratio = 2.619) as explanatory factors. Thirty-four of 78 patients (44%) with coronary stenosis did not have angina symptoms. Multiple logistic regression analysis regarding the lack of angina symptoms identified motor dysfunction (modified Rankin scale ≥ 2) (P = 0.0028, odds ratio = 8.323) as an explanatory factor. The results of the present study suggest that compared with patients without cerebral infarction those with the disorder have a high prevalence of coronary stenosis, and indicate that the development of angina symptoms is influenced by the severity of motor dysfunction.

A pilot study for testing a low-cost 3D design with an inertial sensor for the quantitative assessment of finger tapping in patients with Parkinson's Disease.

Parkinson's disease (PD) is one of the most common neurodegenerative disorders worldwide. Current identification and monitoring of its motor symptoms depends on the clinical expertise. Repetitive finger tapping is one of the most common clinical maneuvers to assess for bradykinesia. Despite the increasing use of technology aids to quantitatively characterize the motor symptoms of PD, there is still a relative lack of clinical evidence to support their widespread use, particularly in low-resource settings. In this pilot study, we used a low-cost design prototype coupled with an inertial sensor is coupled to quantify the frequency of the finger tapping movements in four participants with PD. Repetitive finger tapping was performed using both hands before and after taking levodopa as part of their clinical treatment. The proposed 3D design allowed repetitive movements to be performed without issues. The maximum frequency of finger tapping was in the range of 0.1 to 4.3 Hz. Levodopa was associated with variable changes in the maximum frequency of finger tapping. This pilot study shows the feasibility for low-cost technology to quantitatively characterize repetitive movements in people living with PD.Clinical relevance- In this pilot study, a low-cost inertial sensor coupled to a design prototype was feasible to characterize the frequency of repetitive finger tapping movements in four participants with PD. This method could be used to quantitatively identify and monitor bradykinesia in people living with PD.

Sleep like a bear.

Reduced expression of a platelet protein protects against thrombosis during chronic immobilization.

Immobility-associated thromboprotection is conserved across mammalian species from bear to human.

Venous thromboembolism (VTE) comprising deep venous thrombosis and pulmonary embolism is a major cause of morbidity and mortality. Short-term immobility-related conditions are a major risk factor for the development of VTE. Paradoxically, long-term immobilized free-ranging hibernating brown bears and paralyzed spinal cord injury (SCI) patients are protected from VTE. We aimed to identify mechanisms of immobility-associated VTE protection in a cross-species approach. Mass spectrometry-based proteomics revealed an antithrombotic signature in platelets of hibernating brown bears with heat shock protein 47 (HSP47) as the most substantially reduced protein. HSP47 down-regulation or ablation attenuated immune cell activation and neutrophil extracellular trap formation, contributing to thromboprotection in bears, SCI patients, and mice. This cross-species conserved platelet signature may give rise to antithrombotic therapeutics and prognostic markers beyond immobility-associated VTE.

Prolactin-Raising and Prolactin-Sparing Antipsychotic Drugs and the Risk of Fracture and Fragility Fracture in Patients With Schizophrenia, Dementia, and Other Disorders.

Patients who require antipsychotic drug treatment are at increased risk of fractures, including osteoporosis-related fragility fractures, for reasons related to demographics, illness-related factors, and treatment-related factors. As examples, patients with dementia may be vulnerable to falls due to cognitive and psychomotor impairment, patients with schizophrenia may be vulnerable to injury related to physical restlessness or physical aggression, and patients receiving antipsychotics may suffer falls related to sedation, psychomotor impairment, bradykinesia, or postural hypotension. Antipsychotics may also increase the risk of fracture through long-term hyperprolactinemia and resultant osteoporosis. A meta-analysis of 36 observational studies conducted in mostly elderly samples found that antipsychotic exposure was associated with an increased risk of hip fracture as well as increased risk of any fracture; the findings were consistent in almost all subgroup analyses. An observational study that controlled for confounding by indication and illness severity found that fragility fractures in patients with schizophrenia were associated with higher daily doses, higher cumulative doses, longer duration of treatment, and prolactin-raising rather than prolactin-sparing antipsychotics; in patients receiving prolactin-raising antipsychotics, the concurrent use of aripiprazole appeared protective. The absolute risks of fracture are unknown and could vary depending on patient age, patient sex, indication for antipsychotic use, nature of the antipsychotic (and associated risk of sedation, psychomotor impairment, bradykinesia, and postural hypotension), daily dose prescribed, duration of antipsychotic exposure, baseline risk of fracture, and other risk factors. Patients should therefore be individually evaluated for risk factors for falls and fractures related to sociodemographic, clinical, and treatment-related risk factors. Patients identified to be at risk should be advised about risk-mitigating strategies. If prolactin-raising antipsychotics are required in the long term, prolactin levels should be monitored and prolactin-lowering strategies should be considered. Osteoporosis should be investigated and managed, if identified, to prevent fragility fractures.

Mild cognitive impairment and cognitive-motor relationships in newly diagnosed drug-naive patients with Parkinson's disease.

BACKGROUND AND AIMS: (1) To establish the prevalence of mild cognitive impairment (MCI) in newly diagnosed drug-naive patients with Parkinson's disease adopting recently proposed and more conservative preliminary research criteria. (2) To investigate the relation between cognitive performances, MCI and motor dysfunction. METHODS: 132 consecutive newly diagnosed drug-naive PD patients and 100 healthy controls (HCs) underwent a neuropsychological evaluation covering different cognitive domains. Moreover, on the basis of the Unified Parkinson's Disease Rating Scale II/III, different motor scores were calculated and patients were classified in motor subtypes. 11 patients were excluded from the analysis during clinical follow-up which was continued at least 3 years from the diagnosis; therefore, the final sample included 121 patients. RESULTS: MCI prevalence was higher in PD (14.8%) patients than in HCs (7.0%). PD patients reported lower cognitive performances than HCs in several cognitive domains; HCs also outperformed cognitively preserved PD patients in tasks of episodic verbal memory and in a screening task of executive functions. MCI-PD patients presented a more severe bradykinesia score than non-MCI PD patients and patients mainly characterised by tremor had better performances in some cognitive domains, and specific cognitive-motor relationships emerged. CONCLUSIONS: Although the adoption of more conservative diagnostic criteria identified a lower MCI prevalence, we found evidence that newly diagnosed drug-naive PD patients present a higher risk of MCI in comparison with HCs. Axial symptoms and bradykinesia represent risk factors for MCI in PD patients and a classification of PD patients that highlights the presence/absence of tremor, as proposed in this study, is probably better tailored for the early stages of PD than classifications proposed for more advanced PD stages.