Insight into the Relationship Between Motor and Cognitive Symptoms in Essential Tremor.

Essential tremor (ET) is a heterogeneous disorder characterized by bilateral upper limbs action tremor and, possibly, neurological signs of uncertain significance, including voluntary movement abnormalities and cognitive disturbances, i.e., the so-called 'soft' signs configuring the ET-plus definition. While motor and cognitive disturbances often coexist in ET, their interrelationship remains largely unexplored. Here we aim to further investigate the relationship between motor symptoms, objectively assessed through kinematic analysis, and cognitive dysfunctions in ET. Seventy ET patients underwent clinical examination, as well as kinematic recordings of tremor and finger tapping and a thorough cognitive assessment. We then tested clinic-demographic and kinematic differences between patients with and without cognitive abnormalities, i.e., with mild cognitive impairment (MCI). Correlation analysis served to explore potential associations between kinematic and cognitive data. Forty-three ET patients (61.42%) had MCI. ET-MCI patients exhibited reduced movement velocity during finger tapping compared to those with normal cognition (p < 0.001). Lower movement velocity during finger tapping was associated with poorer cognitive performance. Namely, we observed a correlation between movement velocity and performance on the Babcock Story Immediate and Delayed Recall Test (r = 0.52 and r = 0.45, both p < 0.001), as well as the interference memory task at 10 and 30 s (r = 0.3, p = 0.008 and r = 0.2, p = 0.03). In this study, we have provided data for a better pathophysiological interpretation of motor and cognitive signs in ET, including the role played by the cerebellum or extra-cerebellar areas, which possibly underpin both signs.

The Role of Cerebellum and Basal Ganglia Functional Connectivity in Altered Voluntary Movement Execution in Essential Tremor.

Substantial evidence highlights the role of the cerebellum in the pathophysiology of tremor in essential tremor (ET), although its potential involvement in altered movement execution in this condition remains unclear. This study aims to explore potential correlations between the cerebellum and basal ganglia functional connectivity and voluntary movement execution abnormalities in ET, objectively assessed with kinematic techniques. A total of 20 patients diagnosed with ET and 18 healthy subjects were enrolled in this study. Tremor and repetitive finger tapping were recorded using an optoelectronic kinematic system. All participants underwent comprehensive 3T-MRI examinations, including 3D-T1 and blood-oxygen-level dependent (BOLD) sequences during resting state. Morphometric analysis was conducted on the 3D-T1 images, while a seed-based analysis was performed to investigate the resting-state functional connectivity (rsFC) of dorsal and ventral portions of the dentate nucleus and the external and internal segments of the globus pallidus. Finally, potential correlations between rsFC alterations in patients and clinical as well as kinematic scores were assessed. Finger tapping movements were slower in ET than in healthy subjects. Compared to healthy subjects, patients with ET exhibited altered FC of both dentate and globus pallidus with cerebellar, basal ganglia, and cortical areas. Interestingly, both dentate and pallidal FC exhibited positive correlations with movement velocity in patients, differently from that we observed in healthy subjects, indicating the higher the FC, the faster the finger tapping. The findings of this study indicate the possible role of both cerebellum and basal ganglia in the pathophysiology of altered voluntary movement execution in patients with ET.

Clinical and kinematic characterization of parkinsonian soft signs in essential tremor.

BACKGROUND: Subtle parkinsonian signs, i.e., rest tremor and bradykinesia, are considered soft signs for defining essential tremor (ET) plus. OBJECTIVES: Our study aimed to further characterize subtle parkinsonian signs in a relatively large sample of ET patients from a clinical and neurophysiological perspective. METHODS: We employed clinical scales and kinematic techniques to assess a sample of 82 ET patients. Eighty healthy controls matched for gender and age were also included. The primary focus of our study was to conduct a comparative analysis of ET patients (without any soft signs) and ET-plus patients with rest tremor and/or bradykinesia. Additionally, we investigated the asymmetry and side concordance of these soft signs. RESULTS: In ET-plus patients with parkinsonian soft signs (56.10% of the sample), rest tremor was clinically observed in 41.30% of cases, bradykinesia in 30.43%, and rest tremor plus bradykinesia in 28.26%. Patients with rest tremor had more severe and widespread action tremor than other patients. Furthermore, we observed a positive correlation between the amplitude of action and rest tremor. Most ET-plus patients had an asymmetry of rest tremor and bradykinesia. There was no side concordance between these soft signs, as confirmed through both clinical examination and kinematic evaluation. CONCLUSIONS: Rest tremor and bradykinesia are frequently observed in ET and are often asymmetric but not concordant. Our findings provide a better insight into the phenomenology of ET and suggest that the parkinsonian soft signs (rest tremor and bradykinesia) in ET-plus may originate from distinct pathophysiological mechanisms.

Facial emotion expressivity in patients with Parkinson's and Alzheimer's disease.

Parkinson's disease (PD) and Alzheimer's disease (AD) are neurodegenerative disorders with some overlapping clinical features. Hypomimia (reduced facial expressivity) is a prominent sign of PD and it is also present in AD. However, no study has experimentally assessed hypomimia in AD and compared facial expressivity between PD and AD patients. We compared facial emotion expressivity in patients with PD, AD, and healthy controls (HCs). Twenty-four PD patients, 24 AD patients and 24 HCs were videotaped during neutral facial expressions and while posing six facial emotions (anger, surprise, disgust, fear, happiness, and sadness). Fifteen raters were asked to evaluate the videos using MDS-UPDRS-III (item 3.2) and to identify the corresponding emotion from a seven-forced-choice response format. We measured the percentage of accuracy, the reaction time (RT), and the confidence level (CL) in the perceived accuracy of the raters' responses. We found the highest MDS-UPDRS 3.2 scores in PD, and higher in AD than HCs. When evaluating the posed expression captures, raters identified a lower percentage of correct answers in the PD and AD groups than HCs. There was no difference in raters' response accuracy between the PD and AD. No difference was observed in RT and CL data between groups. Hypomimia in patients correlated positively with the global MDS-UPDRS-III and negatively with Mini Mental State Examination scores. PD and AD patients have a similar pattern of reduced facial emotion expressivity compared to controls. These findings hold potential pathophysiological and clinical implications.

Relationship between the interlimb transfer of a visuomotor learning task and interhemispheric inhibition in healthy humans.

The "interlimb transfer" phenomenon consists of improved performance of the trained and untrained contralateral limbs after unilateral motor practice. We here assessed whether a visuomotor learning task can be transferred from one hemisphere to the other, whether this occurs symmetrically, and the cortical neurophysiological correlates of this phenomenon, focusing on interhemispheric connectivity measures. We enrolled 33 healthy subjects (age range: 24-73 years). Participants underwent two randomized sessions, which investigated the transfer from the dominant to the nondominant hand and vice versa. Measures of cortical and intracortical excitability and interhemispheric inhibition were assessed through transcranial magnetic stimulation before and after a visuomotor task. The execution of the visuomotor task led to an improvement in motor performance with the dominant and nondominant hands and induced a decrease in intracortical inhibition in the trained hemisphere. Participants were also able to transfer the visuomotor learned skill. The interlimb transfer, however, only occurred from the dominant to the nondominant hand and positively correlated with individual learning-related changes in interhemispheric inhibition. We here demonstrated that the "interlimb transfer" of a visuomotor task occurs asymmetrically and relates to the modulation of specific inhibitory interhemispheric connections. The study results have pathophysiological, clinical, and neuro-rehabilitative implications.

Objective assessment of the effects of opicapone in Parkinson's disease through kinematic analysis.

BACKGROUND: Opicapone (OPC) is a third-generation, selective peripheral COMT inhibitor that improves peripheral L-DOPA bioavailability and reduces OFF time and end-of-dose motor fluctuations in Parkinson's disease (PD) patients. OBJECTIVES: In this study, we objectively assessed the effects of adding OPC to L-DOPA on bradykinesia in PD through kinematic analysis of finger movements. METHODS: We enrolled 20 treated patients with PD and motor fluctuations. Patients underwent two experimental sessions (L-DOPA, L-DOPA + OPC), separated by at least 1 week. In each session, patients were clinically evaluated and underwent kinematic movement analysis of repetitive finger movements at four time points: (i) before their usual morning dose of L-DOPA (T0), (ii) 30 min (T1), (iii) 1 h and 30 min (T2), and (iv) 3 h and 30 min after the L-DOPA intake (T3). RESULTS: Movement velocity and amplitude of finger movements were higher in PD patients during the session with OPC compared to the session without OPC at all the time points tested. Importantly, the variability of finger movement velocity and amplitude across T0-T3 was significantly lower in the L-DOPA + OPC than L-DOPA session. CONCLUSIONS: This study is the first objective assessment of the effects of adding OPC to L-DOPA on bradykinesia in patients with PD and motor fluctuations. OPC, in addition to the standard dopaminergic therapy, leads to significant improvements in bradykinesia during clinically relevant periods associated with peripheral L-DOPA dynamics, i.e., the OFF state in the morning, delayed-ON, and wearing-OFF periods.

The golden hour in shock management: do a lot, do it quickly.

Cardiogenic shock can be defined as a state of inadequate organ perfusion linked primarily to cardiac pump dysfunction. The two predominant causes of this condition are acute myocardial infarction and acutely decompensated heart failure (ADHF). In recent years, a significant increase in cases of cardiogenic shock from ADHF has been described. Recent evidence has defined that the factors with the greatest impact on the prognosis in this context are the early clinical assessment, the definition of the aetiology, the timely application of pharmacological therapies, or individualized mechanical supports for the circulation. Haemodynamic monitoring can help in the phenotyping of cardiogenic shock and therefore guide therapeutic choices, especially if implemented with the aid of advanced monitoring tools such as the Swan-Ganz catheter. Finally, the presence of a dedicated shock team in the 'hub' centres is fundamental, which facilitates the choice of the best therapeutic strategy on a case-by-case basis.

Longitudinal study of clinical and neurophysiological features in essential tremor.

BACKGROUND AND PURPOSE: Essential tremor (ET) is a common and heterogeneous disorder characterized by postural/kinetic tremor of the upper limbs and other body segments and by non-motor symptoms, including cognitive and psychiatric abnormalities. Only a limited number of longitudinal studies have comprehensively and simultaneously investigated motor and non-motor symptom progression in ET. Possible soft signs that configure the ET-plus diagnosis are also under-investigated in follow-up studies. We aimed to longitudinally investigate the progression of ET manifestations by means of clinical and neurophysiological evaluation. METHODS: Thirty-seven ET patients underwent evaluation at baseline (T0) and at follow-up (T1; mean interval ± SD = 39.89 ± 9.83 months). The assessment included the clinical and kinematic evaluation of tremor and voluntary movement execution, as well as the investigation of cognitive and psychiatric disorders. RESULTS: A higher percentage of patients showed tremor in multiple body segments and rest tremor at T1 as compared to T0 (all p-values < 0.01). At T1, the kinematic analysis revealed reduced finger-tapping movement amplitude and velocity as compared to T0 (both p-values < 0.001). The prevalence of cognitive and psychiatric disorders did not change between T0 and T1. Female sex, absence of family history, and rest tremor at baseline were identified as predictive factors of worse disease progression. CONCLUSIONS: ET progression is characterized by the spread of tremor in multiple body segments and by the emergence of soft signs. We also identified possible predictors of disease worsening. The results contribute to a better understanding of ET classification and pathophysiology.

The role of laboratory investigations in the classification of tremors.

INTRODUCTION: Tremor is the most common movement disorder. Although clinical examination plays a significant role in evaluating patients with tremor, laboratory tests are useful to classify tremors according to the recent two-axis approach proposed by the International Parkinson and Movement Disorders Society. METHODS: In the present review, we will discuss the usefulness and applicability of the various diagnostic methods in classifying and diagnosing tremors. We will evaluate a number of techniques, including laboratory and genetic tests, neurophysiology, and neuroimaging. The role of newly introduced innovative tremor assessment methods will also be discussed. RESULTS: Neurophysiology plays a crucial role in tremor definition and classification, and it can be useful for the identification of specific tremor syndromes. Laboratory and genetic tests and neuroimaging may be of paramount importance in identifying specific etiologies. Highly promising innovative technologies are being developed for both clinical and research purposes. CONCLUSIONS: Overall, laboratory investigations may support clinicians in the diagnostic process of tremor. Also, combining data from different techniques can help improve understanding of the pathophysiological bases underlying tremors and guide therapeutic management.

Acute heart failure: differential diagnosis and treatment.

Acute heart failure is a heterogeneous clinical syndrome and is the first cause of unplanned hospitalization in people >65 years. Patients with heart failure may have different clinical presentations according to clinical history, pre-existing heart disease, and pattern of intravascular congestion. A comprehensive assessment of clinical, echocardiographic, and laboratory data should aid in clinical decision-making and treatment. In some cases, a more accurate evaluation of patient haemodynamics via a pulmonary artery catheter may be necessary to undertake and guide escalation and de-escalation of therapy, especially when clinical, echo, and laboratory data are inconclusive or in the presence of right ventricular dysfunction. Similarly, a pulmonary artery catheter may be useful in patients with cardiogenic shock undergoing mechanical circulatory support. With the subsequent de-escalation of therapy and haemodynamic stabilization, the implementation of guideline-directed medical therapy should be pursued to reduce the risk of subsequent heart failure hospitalization and death, paying particular attention to the recognition and treatment of residual congestion.

Neurophysiological assessment of juvenile parkinsonism due to primary monoamine neurotransmitter disorders.

No studies have investigated voluntary movement abnormalities and their neurophysiological correlates in patients with parkinsonism due to inherited primary monoamine neurotransmitter (NT) disorders. Nine NT disorders patients and 16 healthy controls (HCs) were enrolled. Objective measurements of repetitive finger tapping were obtained using a motion analysis system. Primary motor cortex (M1) excitability was assessed by recording the input/output (I/O) curve of motor-evoked potentials (MEP) and using a conditioning test paradigm for short-interval intracortical inhibition (SICI) assessment. M1 plasticity-like mechanisms were indexed according to MEPs amplitude changes after the paired associative stimulation protocol. Patient values were considered abnormal if they were greater or lower than two standard deviations from the average HCs value. Patients with aromatic amino acid decarboxylase, tyrosine hydroxylase, and 6-pyruvoyl-tetrahydropterin synthase defects showed markedly reduced velocity (5/5 patients), reduced movement amplitude, and irregular rhythm (4/5 patients). Conversely, only 1 out of 3 patients with autosomal-dominant GTPCH deficiency showed abnormal movement parameters. Interestingly, none of the patients had a progressive reduction in movement amplitude or velocity during the tapping sequence (no sequence effect). Reduced SICI was the most prominent neurophysiological abnormality in patients (5/9 patients). Finally, the I/O curve slope correlated with movement velocity and rhythm in patients. We provided an objective assessment of finger tapping abnormalities in monoamine NT disorders. We also demonstrated M1 excitability changes possibly related to alterations in motor execution. Our results may contribute to a better understanding of the pathophysiology of juvenile parkinsonism due to dopamine deficiency.

Clinical and Kinematic Features of Valproate-Induced Tremor and Differences with Essential Tremor.

Tremor is a common movement disorder that can be induced by medications, including valproate, which is used for the treatment of epilepsy. However, the clinical and neurophysiological features of valproate-induced tremor are still under-investigated. We performed a clinical and kinematic assessment of valproate-induced tremor by considering tremor body distribution and activation conditions. We investigated possible correlations between demographic and clinical data and kinematic features. Valproate-induced tremor results were also compared with those collected in a large sample of patients with essential tremor. Sixteen valproate-induced tremor patients and 93 essential tremor patients were enrolled. All participants underwent a standardised neurological examination and video recording. Patients also underwent an objective assessment of postural, kinetic and rest tremor of the upper limbs and head tremor through kinematic analysis. Nonparametric tests were used for statistical comparisons between the two groups. Clinical evaluation showed a higher occurrence of rest tremor as well as head or voice, and lower limb involvement in patients with valproate-induced tremor. Kinematic analysis showed a substantial variability in the tremor features of patients with valproate-induced tremor. Compared to essential tremor, we found a higher occurrence of rest tremor of the upper limbs and the involvement of more body segments in valproate-induced tremor patients. Valproate-induced tremor has distinctive clinical and kinematic features, which may suggest that valproate interferes with the cerebellar functions.

Tremor Distribution and the Variable Clinical Presentation of Essential Tremor.

In addition to having postural and kinetic tremor of the upper limbs, some patients with essential tremor (ET) may have head tremor as well as cognitive and psychiatric disorders. We aimed to investigate whether the variable clinical presentation in ET patients, including motor and non-motor symptoms, differs in patients with and without head tremor. We consecutively enrolled 70 patients with a diagnosis of ET. Tremor severity was assessed by means of clinical rating scales. Patients also underwent kinematic recordings of postural and kinetic tremor of the upper limbs based on an optoelectronic system. Several neuropsychological tests were also administered. Finally, we adopted the structured interviews for DSM-IV, SCID-I, and SCID-II to investigate psychiatric and personality disorders. ET patients with upper limb tremor plus head tremor exhibited more severe kinetic tremor of the upper limbs and a higher occurrence of axis I psychiatric disorders than ET patients with upper limb tremor only. Cognitive and other motor and psychiatric features did not differ significantly with respect to tremor distribution. The study findings support the hypothesis that body tremor distribution, i.e., the presence of head tremor, influences the variable clinical presentation of ET. The study results support the notion that cases with head tremor may represent a distinct ET subtype, characterized by a prominent cerebellar involvement, and that psychiatric disorders should be considered as a specific manifestation of ET.

A Novel KCNQ2 Variant in a Patient with a Combined Tremor Syndrome.

Background: Tremor disorders have various genetic causes. Case report: A 60-year-old female with a family history of tremor presented a combined tremor syndrome, transient episodes of loss of contact and speech disturbances, as well as distal painful symptoms. Genetic screening revealed a novel heterozygous missense variant in the KCNQ2 gene. Discussion: The KCNQ2 protein regulates action potential firing, and mutations in its gene are associated with epilepsy and neuropathic pain. The identified variant, although of uncertain significance, may disrupt KCNQ2 function and also play a role in tremor pathogenesis. This case highlights the importance of genetic screening in combined tremor disorders.

Theta-tACS modulates cerebellar-related motor functions and cerebellar-cortical connectivity.

OBJECTIVE: To evaluate the effects of cerebellar transcranial alternating current stimulation (tACS) delivered at cerebellar-resonant frequencies, i.e., theta (θ) and gamma (γ), on upper limb motor performance and cerebellum-primary motor cortex (M1) connectivity, as assessed by cerebellar-brain inhibition (CBI), in healthy subjects. METHODS: Participants underwent cerebellar-tACS while performing three cerebellar-dependent motor tasks: (i) rhythmic finger-tapping, (ii) arm reaching-to-grasp ('grasping') and (iii) arm reaching-to-point ('pointing') an object. Also, we evaluated possible changes in CBI during cerebellar-tACS. RESULTS: θ-tACS decreased movement regularity during the tapping task and increased the duration of the pointing task compared to sham- and γ-tACS. Additionally, θ-tACS increased the CBI effectiveness (greater inhibition). The effect of θ-tACS on movement rhythm correlated with CBI changes and less tapping regularity corresponded to greater CBI. CONCLUSIONS: Cerebellar-tACS delivered at the θ frequency modulates cerebellar-related motor behavior and this effect is, at least in part, mediated by changes in the cerebellar inhibitory output onto M1. The effects of θ-tACS may be due to the modulation of cerebellar neurons that resonate to the θ rhythm. SIGNIFICANCE: These findings contribute to a better understanding of the physiological mechanisms of motor control and provide new evidence on cerebellar non-invasive brain stimulation.

Interhemispheric imbalance and bradykinesia features in Parkinson's disease.

In patients with Parkinson's disease, the connectivity between the two primary motor cortices may be altered. However, the correlation between asymmetries of abnormal interhemispheric connections and bradykinesia features has not been investigated. Furthermore, the potential effects of dopaminergic medications on this issue remain largely unclear. The aim of the present study is to investigate the interhemispheric connections in Parkinson's disease by transcranial magnetic stimulation and explore the potential relationship between interhemispheric inhibition and bradykinesia feature asymmetry in patients. Additionally, we examined the impact of dopaminergic therapy on neurophysiological and motor characteristics. Short- and long-latency interhemispheric inhibition was measured in 18 Parkinson's disease patients and 18 healthy controls, bilaterally. We also assessed the corticospinal and intracortical excitability of both primary motor cortices. We conducted an objective analysis of finger-tapping from both hands. Correlation analyses were performed to explore potential relationships among clinical, transcranial magnetic stimulation and kinematic data in patients. We found that short- and long-latency interhemispheric inhibition was reduced (less inhibition) from both hemispheres in patients than controls. Compared to controls, finger-tapping movements in patients were slower, more irregular, of smaller amplitudes and characterized by a progressive amplitude reduction during movement repetition (sequence effect). Among Parkinson's disease patients, the degree of short-latency interhemispheric inhibition imbalance towards the less affected primary motor cortex correlated with the global clinical motor scores, as well as with the sequence effect on the most affected hand. The greater the interhemispheric inhibition imbalance towards the less affected hemisphere (i.e. less inhibition from the less to the most affected primary motor cortex than that measured from the most to the less affected primary motor cortex), the more severe the bradykinesia in patients. In conclusion, the inhibitory connections between the two primary motor cortices in Parkinson's disease are reduced. The interhemispheric disinhibition of the primary motor cortex may have a role in the pathophysiology of specific bradykinesia features in patients, i.e. the sequence effect.