Metabolic Profile in Rats during Long-Term Restriction of Motor Activity.

We performed a comprehensive study of protein (total protein, medium-molecular-weight peptides, creatinine, and urea), purine (uric acid), and lipid (cholesterol, triglycerides) metabolism, activity of AST, ALT, and acid phosphatase in blood plasma of white male rats under conditions of restriction of motor activity up to 28 days. Patterns of changes in metabolic profile during hypokinesia were established: prevalence of catabolic processes and atherogenic shifts in the lipid spectrum with maximum manifestation on 14-21 days of the experiment.

Deep learning of Parkinson's movement from video, without human-defined measures.

BACKGROUND: The core clinical sign of Parkinson's disease (PD) is bradykinesia, for which a standard test is finger tapping: the clinician observes a person repetitively tap finger and thumb together. That requires an expert eye, a scarce resource, and even experts show variability and inaccuracy. Existing applications of technology to finger tapping reduce the tapping signal to one-dimensional measures, with researcher-defined features derived from those measures. OBJECTIVES: (1) To apply a deep learning neural network directly to video of finger tapping, without human-defined measures/features, and determine classification accuracy for idiopathic PD versus controls. (2) To visualise the features learned by the model. METHODS: 152 smartphone videos of 10s finger tapping were collected from 40 people with PD and 37 controls. We down-sampled pixel dimensions and videos were split into 1 s clips. A 3D convolutional neural network was trained on these clips. RESULTS: For discriminating PD from controls, our model showed training accuracy 0.91, and test accuracy 0.69, with test precision 0.73, test recall 0.76 and test AUROC 0.76. We also report class activation maps for the five most predictive features. These show the spatial and temporal sections of video upon which the network focuses attention to make a prediction, including an apparent dropping thumb movement distinct for the PD group. CONCLUSIONS: A deep learning neural network can be applied directly to standard video of finger tapping, to distinguish PD from controls, without a requirement to extract a one-dimensional signal from the video, or pre-define tapping features.

Differential components of bradykinesia in Parkinson's disease revealed by deep brain stimulation.

Bradykinesia is a term describing several manifestations of movement disruption caused by Parkinson's disease (PD), including movement slowing, amplitude reduction, and gradual decrease of speed and amplitude over multiple repetitions of the same movement. Deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves bradykinesia in patients with PD. We examined the effect of DBS on specific components of bradykinesia when applied at two locations within the STN, using signal processing techniques to identify the time course of amplitude and frequency of repeated hand pronation-supination movements performed by participants with and without PD. Stimulation at either location increased movement amplitude, increased frequency, and decreased variability, though not to the range observed in the control group. Amplitude and frequency showed decrement within trials, which was similar in PD and control groups and did not change with DBS. Decrement across trials, by contrast, differed between PD and control groups, and was reduced by stimulation. We conclude that DBS improves specific aspects of movement that are disrupted by PD, whereas it does not affect short-term decrement that could reflect muscular fatigue.NEW & NOTEWORTHY In this study, we examined different components of bradykinesia in patients with Parkinson's disease (PD). We identified different components through signal processing techniques and their response to deep brain stimulation (DBS). We found that some components of bradykinesia respond to stimulation, whereas others do not. This knowledge advances our understanding of brain mechanisms that control movement speed and amplitude.

Differential Responses to Low- and High-Frequency Subthalamic Nucleus Deep Brain Stimulation on Sensor-Measured Components of Bradykinesia in Parkinson's Disease.

INTRODUCTION: The current approach to assessing bradykinesia in Parkinson's Disease relies on the Unified Parkinson's Disease Rating Scale (UPDRS), which is a numeric scale. Inertial sensors offer the ability to probe subcomponents of bradykinesia: motor speed, amplitude, and rhythm. Thus, we sought to investigate the differential effects of high-frequency compared to low-frequency subthalamic nucleus (STN) deep brain stimulation (DBS) on these quantified facets of bradykinesia. METHODS: We recruited advanced Parkinson's Disease subjects with a chronic bilateral subthalamic nucleus (STN) DBS implantation to a single-blind stimulation trial where each combination of medication state (OFF/ON), electrode contacts, and stimulation frequency (60 Hz/180 Hz) was assessed. The Kinesia One sensor system was used to measure upper limb bradykinesia. For each stimulation trial, subjects performed extremity motor tasks. Sensor data were recorded continuously. We identified STN DBS parameters that were associated with improved upper extremity bradykinesia symptoms using a mixed linear regression model. RESULTS: We recruited 22 subjects (6 females) for this study. The 180 Hz STN DBS (compared to the 60 Hz STN DBS) and dopaminergic medications improved all subcomponents of upper extremity bradykinesia (motor speed, amplitude, and rhythm). For the motor rhythm subcomponent of bradykinesia, ventral contacts yielded improved symptom improvement compared to dorsal contacts. CONCLUSION: The differential impact of high- and low-frequency STN DBS on the symptoms of bradykinesia may advise programming for these patients but warrants further investigation. Wearable sensors represent a valuable addition to the armamentarium that furthers our ability to conduct objective, quantitative clinical assessments.

Rapid Voluntary Blinking as a Clinical Marker of Parkinson's Disease.

Reduced spontaneous blinking is a recognized Parkinson's disease (PD) feature. In contrast, voluntary blinking has been less studied and might serve as a measurable marker of facial bradykinesia. We tested 31 PD patients and 31 controls. Participants were filmed during conversation and a rapid blinking task. Both tasks were videorecorded to count the number of blinks per second. PD patients had lower blink rates. Rapid blinking accurately discriminated between groups with 77% sensitivity and 71% specificity. To conclude, rapid blinking may be a simple and quantifiable task of facial bradykinesia.

Decreased blinking without conscious effort is a well-known characteristic of Parkinson's disease (PD). However, voluntary blinking, which is blinking on purpose, has not been studied as much and could be a sign of slower facial movements. We studied a group of people with PD and another one without the disease. We recorded videos of them talking and doing a task where they blinked quickly. Then, we counted how many times they blinked per second in each video. We found that people with PD blinked less often. The rapid blinking task accurately distinguished between those with PD and those without it, being correct about 77% of the time for spotting PD and 71% for spotting non-PD. In conclusion, the rapid blinking task could be a simple and measurable way to identify slower facial movements in PD.

Characterizing Disease Progression in Parkinson's Disease from Videos of the Finger Tapping Test.

INTRODUCTION: Parkinson's disease (PD) is characterized by motor symptoms whose progression is typically assessed using clinical scales, namely the Movement Disorder Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS). Despite its reliability, the scale is bounded by a 5-point scale that limits its ability to track subtle changes in disease progression and is prone to subjective interpretations. We aimed to develop an automated system to objectively quantify motor symptoms in PD using Machine Learning (ML) algorithms to analyze videos and capture nuanced features of disease progression. METHODS: We analyzed videos of the Finger Tapping test, a component of the MDS-UPDRS, from 24 healthy controls and 66 PD patients using ML algorithms for hand pose estimation. We computed multiple movement features related to bradykinesia from videos and employed a novel tiered classification approach to predict disease severity that employed different features according to severity. We compared our video-based disease severity prediction approach against other approaches recently introduced in the literature. RESULTS: Traditional kinematics features such as amplitude and velocity changed linearly with disease severity, while other non-traditional features displayed non-linear trends. The proposed disease severity prediction approach demonstrated superior accuracy in detecting PD and distinguishing between different levels of disease severity when compared to existing approaches.

Why so slow? Models of parkinsonian bradykinesia.

Bradykinesia, or slowness of movement, is a defining feature of Parkinson disease (PD) and a major contributor to the negative effects on quality of life associated with this disorder and related conditions. A dominant pathophysiological model of bradykinesia in PD has existed for approximately 30 years and has been the basis for the development of several therapeutic interventions, but accumulating evidence has made this model increasingly untenable. Although more recent models have been proposed, they also appear to be flawed. In this Perspective, I consider the leading prior models of bradykinesia in PD and argue that a more functionally related model is required, one that considers changes that disrupt the fundamental process of accurate information transmission. In doing so, I review emerging evidence of network level functional connectivity changes, information transfer dysfunction and potential motor code transmission error and present a novel model of bradykinesia in PD that incorporates this evidence. I hope that this model may reconcile inconsistencies in its predecessors and encourage further development of therapeutic interventions.

Short-term effects of Pilates-based exercise on upper limb strength and function in people with Parkinson's disease.

BACKGROUND: People with Parkinson's disease (PD) have impaired upper limb motor coordination, limiting the execution of activities of daily living. This study investigated the feasibility and safety of a short-term Pilates-based exercise program in the treatment of upper limb motor coordination for people with PD. METHODS: Fifteen patients - n (%) 4 women/11 men (27/73), median [interquartile range] age 66 [9] years - participated in this quasi-experimental (before-and-after) clinical trial. Patients underwent a 6-week (30 min/day, 3 days/week) Pilates exercise program using Reformer, Cadillac, Chair, and Barrel equipment. Feasibility was evaluated by adherence to the program and the ability to perform the exercises including progressions on difficulty. Safety was evaluated based on self-reported adverse events. Clinical and functional trends before and after the intervention were also computed regarding handgrip strength (HGS), fine motor coordination (9 Hole Peg Test; 9HPT), bradykinesia (Movement Disorder Society - Unified Parkinson's disease Rating Scale; MDS-UPDRS), and upper limb functionality (Test D'évaluation des Membres Supérieurs des Personnes Âgées, TEMPA). RESULTS: Of the 18 Pilates sessions, exercise adherence was 100%. The only adverse event observed was mild muscle pain. Pre-post differences were observed only for body bradykinesia and hypokinesia (1.0 [0.0] vs. 0.0 [1.0] s, adjusted p = 0.048). CONCLUSIONS: A short-term Pilates-based exercise program in the treatment of upper limb muscle strength, manual dexterity, bradykinesia, and functionality is feasible and safe for people with PD. Changes in upper limb bradykinesia encourage randomized clinical trials.

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.

Disentangling Bradykinesia and Rigidity in Parkinson's Disease: Evidence from Short- and Long-Term Subthalamic Nucleus Deep Brain Stimulation.

OBJECTIVE: Bradykinesia and rigidity are considered closely related motor signs in Parkinson disease (PD), but recent neurophysiological findings suggest distinct pathophysiological mechanisms. This study aims to examine and compare longitudinal changes in bradykinesia and rigidity in PD patients treated with bilateral subthalamic nucleus deep brain stimulation (STN-DBS). METHODS: In this retrospective cohort study, the clinical progression of appendicular and axial bradykinesia and rigidity was assessed up to 15 years after STN-DBS in the best treatment conditions (ON medication and ON stimulation). The severity of bradykinesia and rigidity was examined using ad hoc composite scores from specific subitems of the Unified Parkinson's Disease Rating Scale motor part (UPDRS-III). Short- and long-term predictors of bradykinesia and rigidity were analyzed through linear regression analysis, considering various preoperative demographic and clinical data, including disease duration and severity, phenotype, motor and cognitive scores (eg, frontal score), and medication. RESULTS: A total of 301 patients were examined before and 1 year after surgery. Among them, 101 and 56 individuals were also evaluated at 10-year and 15-year follow-ups, respectively. Bradykinesia significantly worsened after surgery, especially in appendicular segments (p < 0.001). Conversely, rigidity showed sustained benefit, with unchanged clinical scores compared to preoperative assessment (p > 0.05). Preoperative motor disability (eg, composite scores from the UPDRS-III) predicted short- and long-term outcomes for both bradykinesia and rigidity (p < 0.01). Executive dysfunction was specifically linked to bradykinesia but not to rigidity (p < 0.05). INTERPRETATION: Bradykinesia and rigidity show long-term divergent progression in PD following STN-DBS and are associated with independent clinical factors, supporting the hypothesis of partially distinct pathophysiology. ANN NEUROL 2024;96:234-246.

Deep brain stimulation of symptom-specific networks in Parkinson's disease.

Deep Brain Stimulation can improve tremor, bradykinesia, rigidity, and axial symptoms in patients with Parkinson's disease. Potentially, improving each symptom may require stimulation of different white matter tracts. Here, we study a large cohort of patients (N = 237 from five centers) to identify tracts associated with improvements in each of the four symptom domains. Tremor improvements were associated with stimulation of tracts connected to primary motor cortex and cerebellum. In contrast, axial symptoms are associated with stimulation of tracts connected to the supplementary motor cortex and brainstem. Bradykinesia and rigidity improvements are associated with the stimulation of tracts connected to the supplementary motor and premotor cortices, respectively. We introduce an algorithm that uses these symptom-response tracts to suggest optimal stimulation parameters for DBS based on individual patient's symptom profiles. Application of the algorithm illustrates that our symptom-tract library may bear potential in personalizing stimulation treatment based on the symptoms that are most burdensome in an individual patient.

Hyperkinetic and Hypokinetic Movement Disorders in SSPE: A Systematic Review of Case Reports and Case Series.

Background: Subacute Sclerosing Panencephalitis (SSPE) typically presents with periodic myoclonus; however, a spectrum of movement disorders including dystonia, chorea, tremor, and parkinsonism have also been described. This review aims to evaluate the array of movement disorders in SSPE, correlating them with neuroimaging findings, disease stages, and patient outcomes. Methods: A comprehensive review of published case reports and case series was conducted on patients with SSPE exhibiting movement disorders other than periodic myoclonus. PRISMA guidelines were followed, and the protocol was registered with PROSPERO (2023 CRD42023434650). A comprehensive search of multiple databases yielded 37 reports detailing 39 patients. Dyken's criteria were used for SSPE diagnosis, and the International Movement Disorders Society definitions were applied to categorize movement disorders. Results: The majority of patients were male, with an average age of 13.8 years. Approximately, 80% lacked a reliable vaccination history, and 39% had prior measles infections. Dystonia was the most common movement disorder (49%), followed by parkinsonism and choreoathetosis. Rapid disease progression was noted in 64% of cases, with a disease duration of ≤6 months in 72%. Neuroimaging showed T2/FLAIR MR hyperintensities, primarily periventricular, with 26% affecting the basal ganglia/thalamus. Brain biopsies revealed inflammatory and neurodegenerative changes. Over half of the patients (56%) reached an akinetic mute state or died. Conclusion: SSPE is associated with diverse movement disorders, predominantly hyperkinetic. The prevalence of dystonia suggests basal ganglia dysfunction.

Impaired performance of rapid grip in people with Parkinson's disease and motor segmentation.

Bradykinesia, or slow movement, is a defining symptom of Parkinson's disease (PD), but the underlying neuromechanical deficits that lead to this slowness remain unclear. People with PD often have impaired rates of motor output accompanied by disruptions in neuromuscular excitation, causing abnormal, segmented, force-time curves. Previous investigations using single-joint models indicate that agonist electromyogram (EMG) silent periods cause motor segmentation. It is unknown whether motor segmentation is evident in more anatomically complex and ecologically important tasks, such as handgrip tasks. Aim 1 was to determine how handgrip rates of force change compare between people with PD and healthy young and older adults. Aim 2 was to determine whether motor segmentation is present in handgrip force and EMG measures in people with PD. Subjects performed rapid isometric handgrip pulses to 20-60% of their maximal voluntary contraction force while EMG was collected from the grip flexors and extensors. Dependent variables included the time to 90% peak force, the peak rate of force development, the duration above 90% of peak force, the number of segments in the force-time curve, the number of EMG bursts, time to relaxation from 90% of peak force, and the peak rate of force relaxation. People with PD had longer durations and lower rates of force change than young and older adults. Six of 22 people with PD had motor segmentation. People with PD had more EMG bursts compared to healthy adults and the number of EMG bursts covaried with the number of segments. Thus, control of rapid movement in Parkinson's disease can be studied using isometric handgrip. People with PD have impaired rate control compared to healthy adults and motor segmentation can be studied in handgrip.

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.

Shrew's venom quickly causes circulation disorder, analgesia and hypokinesia.

Multiple representatives of eulipotyphlan mammals such as shrews have oral venom systems. Venom facilitates shrews to hunt and/or hoard preys. However, little is known about their venom composition, and especially the mechanism to hoard prey in comatose states for meeting their extremely high metabolic rates. A toxin (BQTX) was identified from venomous submaxillary glands of the shrew Blarinella quadraticauda. BQTX is specifically distributed and highly concentrated (~ 1% total protein) in the organs. BQTX shares structural and functional similarities to toxins from snakes, wasps and snails, suggesting an evolutional relevancy of venoms from mammalians and non-mammalians. By potentiating thrombin and factor-XIIa and inhibiting plasmin, BQTX induces acute hypertension, blood coagulation and hypokinesia. It also shows strong analgesic function by inhibiting elastase. Notably, the toxin keeps high plasma stability with a 16-h half-life in-vivo, which likely extends intoxication to paralyze or immobilize prey hoarded fresh for later consumption and maximize foraging profit.

Long-Term Persistence of Increased Number of γH2AX+ Peripheral Blood Lymphocytes in Monkeys Exposed to Negative Factors of Space Flights: Ionizing Radiation and Simulated Hypogravity.

We studied the influence of ionizing radiation and hypogravity as negative factors of space flights on DNA damage in peripheral blood lymphocytes of rhesus monkeys at different times after exposure (from 1 to 446 days). The proportion of cells with high numbers of DNA double-strand breaks (DSB), positive for the surrogate DSB marker-protein γH2AX, was monitored using flow cytometry. Some animals were exposed to 7-day antiorthostatic hypokinesia simulating hypogravity, the others to a combined effect of antiorthostatic hypokinesia, whole-body γ-irradiation (2.34 cGy/h, dose 1 Gy), and irradiation of the head with 12C ions (450 MeV, dose 1 Gy). Exposure to antiorthostatic hypokinesia led to a significant increase in the proportion of γH2AX+ lymphocytes only on the first day after exposure, whereas after combined exposure, increased numbers of damaged lymphocytes were recorded up to 42 days after exposure.

Bradykinesia in motoneuron diseases.

OBJECTIVE: Only few studies investigated voluntary movement abnormalities in patients with motoneuron diseases (MNDs) or their neurophysiological correlates. We aimed to kinematically assess finger tapping abnormalities in patients with amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS), as compared to healthy controls (HCs), and their relationship with motoneuron involvement. METHODS: Fourteen ALS and 5 PLS patients were enrolled. Finger tapping was assessed by a motion analysis system. Patients underwent a central motor conduction time assessment, a motor nerve conduction study, and needle electromyography. Data were compared to those of 79 HCs using non-parametric tests. Possible relationships between clinical, kinematic, and neurophysiological data were assessed in patients. RESULTS: As a major finding, ALS and PLS patients performed finger tapping slower than HCs. In both conditions, movement slowness correlated with muscle strength. In ALS, movement slowness also correlated with the amplitude of the compound muscle action potential recorded from the muscles involved in the task and with denervation activity. No correlations were found between slowness, measures of upper motoneuron involvement, and other clinical and neurophysiological data. CONCLUSIONS: This study provides novel information on voluntary movement abnormalities in MNDs. SIGNIFICANCE: The results highlight the pathophysiological role of motoneurons in generating movement slowness.

Comparison of the Parkinson's KinetiGraph to off/on levodopa response testing: Single center experience.

BACKGROUND AND OBJECTIVE: Levodopa off/on testing is frequently performed to assess medication response in patients with Parkinson's disease (PD) as an aid in determining best medical management or potential surgical candidacy. The Parkinson's Kinetigraph (PKG) is a wearable device which generates tremor, bradykinesia (BKS) and dyskinesia (DKS) scores representing motor symptoms over a six-day period. In this study, we compared off/on testing with PKG motor scores. METHODS: Patients were enrolled as part of an observational study: Assessing the Longitudinal Signs in PD, a three-year study evaluating clinical and biomarker evolution in patients with PD taking levodopa. Patients underwent off/on testing at baseline and 6-month visits. A greater than 30% improvement between off and on MDS-Unified Parkinson's Disease Rating Scale scores was considered a robust response. After each visit, patients wore the PKG for 6 days. A bradykinesia score (BKS) greater than 26 and dyskinesia score (DKS) greater than 9 were considered poorly controlled bradykinesia and dyskinesia, respectively. RESULTS: The median BKS at the baseline and 6-month visits were 27.15 and 27.55, respectively, despite a robust median off/on improvement at both visits. In addition, 10/18 (66%) and 7/13 (53.8%) patients with robust off/on improvement at the baseline and 6-month visits, respectively, demonstrated a BKS > 26 or DKS > 9. CONCLUSION: A robust off/on response during a clinic visit does not necessarily reflect adequately controlled motor symptoms. The PKG, by virtue of its continuous recording of motor movements, may provide additional clinically relevant data on motor symptoms which may be useful for prospective observational studies.

DNAJC6 mutation causing cranial-onset dystonia with tremor dominant levodopa non-responsive parkinsonism: A novel phenotype.

DNAJC6 mutation causes two types of phenotypes: slowly progressive parkinsonism with levodopa response and rapidly progressive parkinsonism with additional manifestations like intellectual disability, epilepsy etc. We report a new phenotype wherein an adolescent girl developed blepharospasm followed by jaw opening, lingual and cervical dystonia followed by tremors of limbs (rest and action) with rigidity, bradykinesia. The dystonia-parkinsonism phenotype has not been described. She had novel homozygous missense mutation in DNAJC6 gene.

Beta power and movement-related beta modulation as hallmarks of energy for plasticity induction: Implications for Parkinson's disease.

Extensive work on movement-related beta oscillations (~13-30 Hz) over the sensorimotor areas in both humans and animals has demonstrated that sensorimotor beta power decreases during movement and transiently increases after movement. This beta power modulation has been interpreted as reflecting interactions between sensory and motor cortical areas with attenuation of sensory afferents during movement and their subsequent re-activation for internal models updating. More recent studies in neurologically normal subjects have demonstrated that this movement-related modulation as well as mean beta power at rest increase with practice and that previous motor learning enhances such increases. Conversely, patients with Parkinson's disease (PD) do not show such practice-related increases. Interestingly, a 2-h inactivity period without sleep can restore beta power values to baseline in normal subjects. Based on these results and on those of biochemical and electrophysiological studies in animals, we expand the current interpretation of beta activity and propose that the practice-related increases of beta power over sensorimotor areas are local indices of energy used for engaging plasticity-related activity. This paper provides some preliminary evidence in this respect linking findings of biochemical and electrophysiological studies in both humans and animals. This novel interpretation may explain the high level of beta power at rest, the deficient modulation during movement as well as the decreased skill formation in PD as resulting from deficiency in energy consumption, availability and regulation that are altered in this disease.