Finger Tapping Frequency Research Articles

Age- and sex-related changes in motor functions: a comprehensive assessment and component analysis.

Age-related motor impairments often cause caregiver dependency or even hospitalization. However, comprehensive investigations of the different motor abilities and the changes thereof across the adult lifespan remain sparse. We, therefore, extensively assessed essential basic and complex motor functions in 444 healthy adults covering a wide age range (range 21 to 88 years). Basic motor functions, here defined as simple isolated single or repetitive movements in one direction, were assessed by means of maximum grip strength (GS) and maximum finger-tapping frequency (FTF). Complex motor functions, comprising composite sequential movements involving both proximal and distal joints/muscle groups, were evaluated with the Action Research Arm Test (ARAT), the Jebsen-Taylor Hand Function Test (JTT), and the Purdue Pegboard Test. Men achieved higher scores than women concerning GS and FTF, whereas women stacked more pins per time than men during the Purdue Pegboard Test. There was no significant sex effect regarding JTT. We observed a significant but task-specific reduction of basic and complex motor performance scores across the adult lifespan. Linear regression analyses significantly predicted the participants' ages based on motor performance scores (R2 = 0.502). Of note, the ratio between the left- and right-hand performance remained stable across ages for all tests. Principal Component Analysis (PCA) revealed three motor components across all tests that represented dexterity, force, and speed. These components were consistently present in young (21-40 years), middle-aged (41-60 years), and older (61-88 years) adults, as well as in women and men. Based on the three motor components, K-means clustering analysis differentiated high- and low-performing participants across the adult life span. The rich motor data set of 444 healthy participants revealed age- and sex-dependent changes in essential basic and complex motor functions. Notably, the comprehensive assessment allowed for generating robust motor components across the adult lifespan. Our data may serve as a reference for future studies of healthy subjects and patients with motor deficits. Moreover, these findings emphasize the importance of comprehensively assessing different motor functions, including dexterity, force, and speed, to characterize human motor abilities and their age-related decline.

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.

Kinect-based objective evaluation of bradykinesia in patients with Parkinson's disease.

To quantify bradykinesia in Parkinson's disease (PD) with a Kinect depth camera-based motion analysis system and to compare PD and healthy control (HC) subjects. Fifty PD patients and twenty-five HCs were recruited. The Movement Disorder Society-Sponsored Revision of the Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS III) was used to evaluate the motor symptoms of PD. Kinematic features of five bradykinesia-related motor tasks were collected using Kinect depth camera. Then, kinematic features were correlated with the clinical scales and compared between groups. Significant correlations were found between kinematic features and clinical scales (P < 0.05). Compared with HCs, PD patients exhibited a significant decrease in the frequency of finger tapping (P < 0.001), hand movement (P < 0.001), hand pronation-supination movements (P = 0.005), and leg agility (P = 0.003). Meanwhile, PD patients had a significant decrease in the speed of hand movements (P = 0.003) and toe tapping (P < 0.001) compared with HCs. Several kinematic features exhibited potential diagnostic value in distinguishing PD from HCs with area under the curve (AUC) ranging from 0.684-0.894 (P < 0.05). Furthermore, the combination of motor tasks exhibited the best diagnostic value with the highest AUC of 0.955 (95% CI = 0.913-0.997, P < 0.001). The Kinect-based motion analysis system can be applied to evaluate bradykinesia in PD. Kinematic features can be used to differentiate PD patients from HCs and combining kinematic features from different motor tasks can significantly improve the diagnostic value.

Long-term Physical Exercise Improves Finger Tapping of Patients with Alzheimer's Disease.

Alzheimer's disease (AD) is a chronic neurodegenerative disease that has been characterized by progressive development of long onset early disease with complicated etiology and may cause memory loss, cognitive impairment, and behavioral changes. Physical exercise may play a preventive role in AD. In the present study, we investigated the impact of longer-term physical exercise on the finger tapping of AD patients by comparing the finger tapping of AD patients and healthy controls. In this study, 140 subjects aged ≥ 60 years were enrolled. Group A consisted of 70 subjects (27 males and 43 females) without exercise habits who were selected from Yangpu District (Shanghai, China). Group B consisted of 70 subjects (27 males and 43 females) who were selected from Minxing District (Shanghai, China). All the subjects were right-handed as well. The subjects' data, including subjects' age, weight, height, Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), and finger tapping frequency, were measured. The subjects were matched in age, weight, and height. The AD subjects' MoCA and MMSE scores were noticeably lower than healthy subjects' scores (P<0.001); besides, AD patients with exercise had significantly lower MoCA and MMSE scores than healthy controls with exercise (P<0.001). The finger tapping of AD subjects' left hands was significantly lower than that of healthy subjects without AD (P<0.01), and AD subjects with exercise tapped significantly slower with their left hand than healthy subjects with exercise (P<0.01). Meanwhile, AD subjects with exercise tapped significantly faster with the left hand than AD subjects (P<0.05). The right hands of AD subjects tapped remarkably less than healthy subjects (P<0.01) with or without exercise. Meanwhile, subjects with exercise tapped significantly faster with their right hand than healthy subjects (P<0.05), and AD subjects with exercise tapped significantly faster with their right hand than AD subjects (P<0.05). Long-term physical exercises can improve finger tapping frequency, especially in patients with AD. Finger tapping frequency may be used as an index to monitor the cognitive decline in ageing AD patients.

Digitomotography in children with oro-facial dysfunction (OFD, oro-facial myofunctional disorders) and childhood apraxia of speech (CAS).

Oro-facial dysfunctions (OFDs; oro-facial myofunctional disorders) in children and childhood apraxia of speech (CAS) often cause severe problems in articulation, chewing, swallowing and oral posture. Pathognomonic symptoms could yet not be identified, but central problems in planning, programming, timing and automating oro-facial, as well as other fine motor skills, are assumed to be affected. To investigate the nature of motor and coordinative deficits in OFD and CAS, digitomotography was applied. The testing focused on recording frequency, force, rhythm and regularity of the index finger including speeded and metronome tapping tasks. 25 children with OFD (7 girls and 18 boys, age 7.9±2.3) and 5 children with CAS (0 girls and 5 boys, age 7.6±2.3), and 31 healthy controls (12 girls and 19 boys, age 9.3±2.2) were tested. Statistical significance was accepted at α = 0.05. ANOVA test, non-parametric Mann-Whitney U test, Kruskal-Wallis test and Spearman's rank correlation coefficient were used. Cross-sectional data revealed consistent significant differences between children with OFD and healthy controls concerning frequency, force, rhythm and regularity of index finger tapping. Individuals with CAS showed particularly low results. Tapping results correlated with disease burden. These findings support that underlying superordinated sensorimotor deficits exist. This may help phenotyping and influence diagnostical and therapeutical approaches.

Immediate effects of treadmill walking in individuals with Lewy body dementia and Huntington’s disease

BackgroundTreadmill training may improve gait disorders associated with neurodegenerative diseases. In Parkinson’s disease (PD), treadmill training alters gait patterns after one session, and long-term training improves gait parameters, fall risk, and quality of life. Research questionWhat is the feasibility and safety of using this intervention for people with Lewy body dementia (LBD) or Huntington’s disease (HD)? MethodsIn this observational study, 10 individuals with HD, 8 individuals with LBD, and 10 control individuals walked for 20 min on a treadmill using a speed dependent protocol starting at a slow comfortable speed and increasing incrementally toward their normal overground speed. Feasibility was determined by compliance to protocol and safety by no incidents of abnormal vital signs or expressions of distress. Changes in gait measures, Timed Up and Go (TUG) scores and quantitative motor function measures (Q-Motor; precision grasp force variability, finger and foot tapping frequency) before and after treadmill walking were analyzed using linear models. ResultsTreadmill training is feasible and safe in LBD and HD; although, participants could not initiate treadmill walking at their comfortable overground speeds, and only 3 participants with HD were able to achieve their overground walking speed within the 20-minute session. No changes in gait measures, TUG times, and Q-Motor measures were found among LBD and HD participants after treadmill walking, although control participants demonstrated significant increases in several gait measures, and foot tap frequency (estimated difference = 0.290; p = 0.026). SignificanceLonger and more frequent treadmill sessions may be needed to see gait and motor function effects in LBD and HD. Motor and cognitive impairments associated with these diseases may make them less amenable to the effects of treadmill training.

Quantitative Assessment of Motor Response to a Low Subacute Levodopa Dose in the Differential Diagnosis of Parkinsonisms at Disease Onset: Data from the BoProPark Cohort.

Background:Differential diagnosis between Parkinson’s disease (PD) and atypical parkinsonisms (APs) may be difficult at disease onset. The response to levodopa (LD) is a key supportive feature but its definition is largely empirical. Studies evaluating this issue by quantitative tests are scanty.Objective:We aimed to assess the utility of a subacute low LD dose kinetic-dynamic test in the differential diagnosis between PD and APs. It was applied at the baseline of a prospective follow-up in patients with parkinsonian signs within three years of disease motor onset (“BoProPark” cohort) and eventually diagnosed as PD or APs according to consensus criteria.Methods:Patients under at least 3-month LD therapy received a first morning fasting dose of LD/benserazide or carbidopa (100/25 mg) and underwent simultaneous serial assessments of plasma LD concentration and alternate finger tapping frequency up to 3 h. The main outcome was the extent of LD motor response, calculated by the area under the 3 h tapping effect–time curve (AUC_ETap). A receiver operating characteristic (ROC) curve analysis was performed to establish the optimal AUC_ETap cut-off to differentiate PD and APs.Results:The first 100 consecutive “BoProPark” patients were analyzed. Forty-seven patients were classified as possible, 37 as probable PD and 16 as APs. AUC_ETap medians were similar in the PD subgroups but reduced to a third in APs (p < 0.001). The optimal AUC_ETap cut-off value was >2186 [(tap/min) x min], with a sensitivity of 92% and a specificity of 75%. Accuracy of the test was 0.85 (95% CI 0.74–0.95), p < 0.0001.Conclusion:The estimation of 3 h AUC_ETap after a subacute low LD dose proved a reliable, objective tool to assess LD motor response in our cohort of patients. AUC_ETap value rounded to ≥2200 supports PD diagnosis, while lower values may alert to AP diagnoses.

Mathematical modeling and parameter estimation of levodopa motor response in patients with parkinson disease

Parkinson disease (PD) is characterized by a clear beneficial motor response to levodopa (LD) treatment. However, with disease progression and longer LD exposure, drug-related motor fluctuations usually occur. Recognition of the individual relationship between LD concentration and its effect may be difficult, due to the complexity and variability of the mechanisms involved. This work proposes an innovative procedure for the automatic estimation of LD pharmacokinetics and pharmacodynamics parameters, by a biologically-inspired mathematical model. An original issue, compared with previous similar studies, is that the model comprises not only a compartmental description of LD pharmacokinetics in plasma and its effect on the striatal neurons, but also a neurocomputational model of basal ganglia action selection. Parameter estimation was achieved on 26 patients (13 with stable and 13 with fluctuating LD response) to mimic plasma LD concentration and alternate finger tapping frequency along four hours after LD administration, automatically minimizing a cost function of the difference between simulated and clinical data points. Results show that individual data can be satisfactorily simulated in all patients and that significant differences exist in the estimated parameters between the two groups. Specifically, the drug removal rate from the effect compartment, and the Hill coefficient of the concentration-effect relationship were significantly higher in the fluctuating than in the stable group. The model, with individualized parameters, may be used to reach a deeper comprehension of the PD mechanisms, mimic the effect of medication, and, based on the predicted neural responses, plan the correct management and design innovative therapeutic procedures.

Finger Tapping Outperforms the Traditional Scale in Patients With Peripheral Nerve Damage.

Objective: This study aimed to investigate whether there exist the limits of finger tapping frequency in the peripheral nerve injury detection in upper limb, and the effects of rehabilitation treatment on upper limb with peripheral nerve injury through finger tapping.Methods: Here, 54 patients with peripheral nerve injury in upper limb were selected. We conducted finger tapping frequency test and Lind-mark hand function assessment score on the 54 subjects, and recorded the data 2-week before and after rehabilitation treatment.Results: Finger tapping frequency and Lind-mark hand function assessment score have a high positive correlation regardless of the side of upper limb with peripheral nerve injury before and after the rehabilitation treatment. Finger tapping frequency of the right affected hand after treatment is significantly higher than that of before treatment (male: P < 0.05; female: P < 0.01), while finger tapping frequency of the left affected hand after treatment shows no significant difference compared to before treatment. Meanwhile, finger tapping frequency of the female subjects' unaffected hand after treatment is significantly higher than before treatment (left: P < 0.01; right: P < 0.05), however, this was not observed in male subjects. Based on data analysis, there is a high-correlation between finger tapping frequency and Lind-mark score of the patients' affected hand with brachial plexus nerve injury. A trend of the patients' affected hand with radial nerve injury is similar with brachial plexus nerve injury.Conclusion: Compared with Lind-mark score, finger tapping frequency outperformed in the aspect of speed of neural impulse conduction in patients with peripheral nerve damage.

Can Long-Term Regular Practice of Physical Exercises Including Taichi Improve Finger Tapping of Patients Presenting With Mild Cognitive Impairment?

Background: Mild cognitive impairment (MCI) is a brain disease with both anatomical and functional alterations. There is clear evidence that individuals that are diagnosed with MCI have a high risk to develop dementia in the next 2–5 years compared to an age-matched population with a non-MCI diagnosis. The present study aimed to investigate whether the finger tapping frequency of patients with MCI was different from that of healthy individuals without MCI, and whether Tai Chi, a traditional Chinese movement discipline, could improve the finger tapping frequency of MCI patients.Methods: The study population consisted of subjects of ≥50 years of age. Group one included 40 subjects without exercise habits from communities of Yangpu District in Shanghai, and group two included 60 subjects from a Tai Chi class in Shanghai Elderly University of Huangpu District. The Montreal Cognitive Assessment (MoCA) and a finger tapping test were conducted to assess the finger tapping frequency of all subjects.Results: The MoCA score of MCI subjects was significantly lower compared to subjects without MCI (P < 0.01), and was not influenced by age, weight, or height. The finger tapping frequency of MCI subjects’ left hands was significantly lower compared to that of healthy subjects without MCI (P < 0.01), and a similar trend was observed for the subjects’ right hand. The MoCA score of MCI subjects in the Tai Chi class was significantly lower than that of healthy subjects without MCI (P < 0.01), which was not influenced by age, weight or height. The finger tapping frequency of MCI subjects’ right hands was lower compared to that of healthy subjects in the Tai Chi class without MCI (P < 0.05), but no significant difference regarding the finger tapping frequency of the left hand was observed.Conclusion: These findings suggested that finger tapping frequency of MCI subjects was significantly lower compared to normal subjects without MCI, and long-term Tai Chi exercise could reduce this significant difference. Moreover, there was no significant difference between groups for the subjects’ non-dominant (left) hand.

Repeated Bout Rate Enhancement Is Elicited by Various Forms of Finger Tapping.

Voluntary rhythmic movements, such as, for example, locomotion and other cyclic tasks, are fundamental during everyday life. Patients with impaired neural or motor function often take part in rehabilitation programs, which include rhythmic movements. Therefore, it is imperative to have the best possible understanding of control and behaviour of human voluntary rhythmic movements. A behavioural phenomenon termed repeated bout rate enhancement has been established as an increase of the freely chosen index finger tapping frequency during the second of two consecutive tapping bouts. The present study investigated whether the phenomenon would be elicited when the first bout consisted of imposed passive finger tapping or air tapping. These two forms of tapping were applied since they can be performed without descending drive (passive tapping) and without afferent feedback related to impact (air tapping) – as compared to tapping on a surface. Healthy individuals (n = 33) performed 3-min tapping bouts separated by 10 min rest. Surface electromyographic, kinetic, and kinematic data were recorded. Supportive experiments were made to measure, for example, the cortical sensory evoked potential (SEP) response during the three different forms of tapping. Results showed that tapping frequencies in the second of two consecutive bouts increased by 12.9 ± 14.8% (p < 0.001), 9.9 ± 6.0% (p = 0.001), and 16.8 ± 13.6% (p = 0.005) when the first bout had consisted of tapping, passive tapping, and air tapping, respectively. Rate enhancement occurred without increase in muscle activation. Besides, the rate enhancements occurred despite that tapping, as compared with passive tapping and air tapping, resulted in different cortical SEP responses. Based on the present findings, it can be suggested that sensory feedback in an initial bout increases the excitability of the spinal central pattern generators involved in finger tapping. This can eventually explain the phenomenon of repeated bout rate enhancement seen after a consecutive bout of finger tapping.

Vertical Finger Displacement Is Reduced in Index Finger Tapping During Repeated Bout Rate Enhancement.

The present study analyzed (a)whether a recently reported phenomenon of repeated bout rate enhancement in finger tapping (i.e., a cumulating increase in freely chosen finger tapping frequency following submaximal muscle activation in the form of externally unloaded voluntary tapping) could be replicated and (b)the hypotheses that the faster tapping was accompanied by changed vertical displacement of the fingertip and changed peak force during tapping. Right-handed, healthy, and recreationally active individuals (n = 24) performed two 3-min index finger tapping bouts at freely chosen tapping frequency, separated by 10-min rest. The recently reported phenomenon of repeated bout rate enhancement was replicated. The faster tapping (8.8 ± 18.7taps/min, corresponding to 6.0 ± 11.0%, p = .033) was accompanied by reduced vertical displacement (1.6 ± 2.9mm, corresponding to 6.3 ± 14.9%, p = .012) of the fingertip. Concurrently, peak force was unchanged. The present study points at separate control mechanisms governing kinematics and kinetics during finger tapping.

Time-dependent functional role of the contralesional motor cortex after stroke.

After stroke, movements of the paretic hand rely on altered motor network dynamics typically including additional activation of the contralesional primary motor cortex (M1). The functional implications of contralesional M1 recruitment to date remain a matter of debate.We here assessed the role of contralesional M1 in 12 patients recovering from a first-ever stroke using online transcranial magnetic stimulation (TMS): Short bursts of TMS were administered over contralesional M1 or a control site (occipital vertex) while patients performed different motor tasks with their stroke-affected hand.In the early subacute phase (1–2 weeks post-stroke), we observed significant improvements in maximum finger tapping frequency when interfering with contralesional M1, while maximum grip strength and speeded movement initiation remained unaffected. After > 3 months of motor recovery, disruption of contralesional M1 activity did not interfere with performance in any of the three tasks, similar to what we observed in healthy controls.In patients with mild to moderate motor deficits, contralesional M1 has a task- and time-specific negative influence on motor performance of the stroke-affected hand. Our results help to explain previous contradicting findings on the role of contralesional M1 in recovery of function.

A Mathematical Model of Levodopa Medication Effect on Basal Ganglia in Parkinson's Disease: An Application to the Alternate Finger Tapping Task.

Malfunctions in the neural circuitry of the basal ganglia (BG), induced by alterations in the dopaminergic system, are responsible for an array of motor disorders and milder cognitive issues in Parkinson's disease (PD). Recently Baston and Ursino (2015a) presented a new neuroscience mathematical model aimed at exploring the role of basal ganglia in action selection. The model is biologically inspired and reproduces the main BG structures and pathways, modeling explicitly both the dopaminergic and the cholinergic system. The present work aims at interfacing this neurocomputational model with a compartmental model of levodopa, to propose a general model of medicated Parkinson's disease. Levodopa effect on the striatum was simulated with a two-compartment model of pharmacokinetics in plasma joined with a motor effect compartment. The latter is characterized by the levodopa removal rate and by a sigmoidal relationship (Hill law) between concentration and effect. The main parameters of this relationship are saturation, steepness, and the half-maximum concentration. The effect of levodopa is then summed to a term representing the endogenous dopamine effect, and is used as an external input for the neurocomputation model; this allows both the temporal aspects of medication and the individual patient characteristics to be simulated. The frequency of alternate tapping is then used as the outcome of the whole model, to simulate effective clinical scores. Pharmacokinetic-pharmacodynamic modeling was preliminary performed on data of six patients with Parkinson's disease (both “stable” and “wearing-off” responders) after levodopa standardized oral dosing over 4 h. Results show that the model is able to reproduce the temporal profiles of levodopa in plasma and the finger tapping frequency in all patients, discriminating between different patterns of levodopa motor response. The more influential parameters are the Hill coefficient, related with the slope of the effect sigmoidal relationship, the drug concentration at half-maximum effect, and the drug removal rate from the effect compartment. The model can be of value to gain a deeper understanding on the pharmacokinetics and pharmacodynamics of the medication, and on the way dopamine is exploited in the neural circuitry of the basal ganglia in patients at different stages of the disease progression.

The effect of action observation/execution on mirror neuron system recruitment: an fMRI study in healthy individuals.

Action observation and execution activate regions that are part of the motor and mirror neuron systems (MNS). Using functional magnetic resonance (fMRI), we defined the presence and extent of MNS activation during three different motor tasks with the dominant, right-upper limb in healthy individuals. The influence of the modality of task administration (execution, observation, observation and execution) was also investigated. fMRI scans during the execution (E) of a motor task, the observation (O) of a video showing the same task performed by another person and the simultaneous observation and execution (OE) of the task were obtained from three groups of healthy subjects (15 subjects per group) randomized to perform: a simple motor (SM) task, a complex motor (CM) task and a finalistic motor (FM) task. Manual dexterity was assessed using the 9-hole peg test and maximum finger tapping frequency. MNS activation was higher during FM than SM or CM tasks, independently from the modality of administration (E, O, or OE). Inferior frontal gyrus recruitment was more significant during SM than CM tasks in the E and O conditions. Compared to SM and FM, CM task resulted in increased recruitment of brain regions involved in complex motor task performance. Compared to O and E, OE resulted in the recruitment of additional, specific, brain areas in the cerebellum, temporal and parietal lobes. The modality of administration and the type of task modulated MNS recruitment during motor acts. This might have practical implications for the set-up of individualized motor rehabilitation strategies.

Efficient neuroplasticity induction in chronic stroke patients by an associative brain-computer interface.

Brain-computer interfaces (BCIs) have the potential to improve functionality in chronic stoke patients when applied over a large number of sessions. Here we evaluated the effect and the underlying mechanisms of three BCI training sessions in a double-blind sham-controlled design. The applied BCI is based on Hebbian principles of associativity that hypothesize that neural assemblies activated in a correlated manner will strengthen synaptic connections. Twenty-two chronic stroke patients were divided into two training groups. Movement-related cortical potentials (MRCPs) were detected by electroencephalography during repetitions of foot dorsiflexion. Detection triggered a single electrical stimulation of the common peroneal nerve timed so that the resulting afferent volley arrived at the peak negative phase of the MRCP (BCIassociative group) or randomly (BCInonassociative group). Fugl-Meyer motor assessment (FM), 10-m walking speed, foot and hand tapping frequency, diffusion tensor imaging (DTI) data, and the excitability of the corticospinal tract to the target muscle [tibialis anterior (TA)] were quantified. The TA motor evoked potential (MEP) increased significantly after the BCIassociative intervention, but not for the BCInonassociative group. FM scores (0.8 ± 0.46 point difference, P = 0.01), foot (but not finger) tapping frequency, and 10-m walking speed improved significantly for the BCIassociative group, indicating clinically relevant improvements. Corticospinal tract integrity on DTI did not correlate with clinical or physiological changes. For the BCI as applied here, the precise coupling between the brain command and the afferent signal was imperative for the behavioral, clinical, and neurophysiological changes reported. This association may become the driving principle for the design of BCI rehabilitation in the future. Indeed, no available BCIs can match this degree of functional improvement with such a short intervention.

Pharmacodynamics of a low subacute levodopa dose helps distinguish between multiple system atrophy with predominant Parkinsonism and Parkinson's disease.

The differential diagnosis between multiple system atrophy with predominant parkinsonism (MSA-P) and Parkinson's disease (PD) may be challenging at disease onset. Levodopa responsiveness helps distinguish the two groups, but studies evaluating this issue using objective standardized tests are scanty. We retrospectively examined the extent of levodopa response by an objective kinetic-dynamic test in a series of patients prospectively followed up for a parkinsonian syndrome and eventually diagnosed as MSA-P or PD. Sixteen MSA-P and 31 PD patients under chronic levodopa therapy received a first morning fasting dose of levodopa/benserazide (100/25 mg) or levodopa/carbidopa (125/12.5 or 100/25 mg) and underwent simultaneous serial assessments of plasma levodopa concentration and alternate finger tapping frequency up to 3 h post dosing. The main levodopa pharmacodynamic variables were the maximum percentage increase in tapping frequency over baseline values (ΔTapmax %) and the area under the tapping effect-time curve (AUCTap). Levodopa pharmacokinetics did not show significant differences between MSA-P and PD, whereas both the magnitude and overall extent of levodopa tapping effect were markedly reduced in the MSA-P group (p < 0.001). The combined use of specific cut-off values for both the main pharmacodynamic variables, ΔTapmax % <20% and AUCTap <1900 [(tapping/min)·min], correctly discriminated 15 out of 16 MSA-P patients from PD patients. A combined estimation of these pharmacodynamic variables after a subacute low levodopa dose may be a simple and practical clinical tool to aid the differential diagnosis between MSA-P and PD.

P161. Manipulating motor performance in simple motor tasks by online-TMS: The role of ipsilateral M1

Introduction Coordinated hand movements derive from fine-tuned interactions of various motor regions. Transcranial magnetic stimulation (TMS) allows to test the role of cortical motor areas. Disturbing the activity of the primary motor cortex (M1) ipsilateral to the moving hand via ‘online’ TMS, i.e., applied during task execution, has been shown to alter the recruitment of hand muscles in grip-lift-tasks ( Davare et al., 2007 ). Then again, similar stimulation had no effect on the performance of simple reaction-time tasks ( Nardone et al., 2013 ). Conflicting data might result from differences in stimulation parameters (e.g., stimulation intensity) or from motor task specific effect of online-TMS interference. We, here, applied online TMS to M1 while subjects performed motor-tasks of different complexities with the ipsilateral hand to further our insights into the exact role of the ipsilateral M1 in hand movement. Material and methods 16 healthy, right-handed subjects performed three different motor tasks with the right index finger (simple reaction-time and maximum finger-tapping task) or the right hand (maximum grip strength over one second). TMS Pulses were applied as 10 Hz-trains time-locked to motor task execution. Performance was measured for four different conditions. Real-stimulation was applied at three different intensities: (i) 70%, (ii) 80%, or (iii) 90% of the resting motor threshold (RMT) to the right M1. Sham-stimulation was applied at 90% RMT over parieto-occipital vertex. The order of stimulation blocks was pseudo-randomized across subjects. Results Online TMS applied to the right M1 differentially affected motor task performance with the right (ipsilateral) hand. Maximum finger-tapping frequency and the integrated grip strength time course were significantly reduced by real compared to sham stimulation. Of note, we found a stimulation intensity dependent effect with higher stimulation intensities leading to stronger reduction in motor performance. In contrast, performance in the simple reaction-time task was not affected by online TMS. Discussion We found online TMS applied to M1 to impact on the motor function of the ipsilateral hand. Importantly, the ‘virtual lesion’ effect induced by online TMS strongly depended on the intensity at which pulses were applied and the given motor task. Our results suggest M1 to functionally contribute to the repetitive and timely precise recruitment of ipsilateral hand muscles. Finally, our experimental approach also offers the opportunity to study the altered role of the ipsilateral M1 in disease, e.g., during motor network reorganization following stroke.

Structural brain plasticity modified by action observation training in healthy subjects

Methods: Using a 3T scanner, fMRI scans during the observation (O) of a video showing a task performed by another person and the simultaneous execution and observation (EO) of the same task were obtained from three groups of healthy subjects. Forty-five subjects were randomized into three groups of 15 subjects. Each group had to perform one of the following task: a simple motor task (SM) (flexionextension of the last four fingers of the right hand), a complex motor task (CM) (flexion-extension alternated to abductionadduction of the last four fingers of the right hand) and a transitive motor task (TM) (use of an object with the right hand). Manual dexterity was assessed using the 9-hole peg test (9HPT) and maximum finger tapping frequency (FT). fMRI data were analyzed using SPM8. Significant differences were consideredwith p< 0.05. The studywas approved by the local Ethical Committee and an informed consent was signed by each subject. Results: Demographic and manual dexterity data did not differ between groups. DuringO task, the SM and TMgroups had an increased activation of the bilateral inferior frontal gyrus compared toCM.DuringOandOE tasks, theTMgroup experienced a higher activation of the left inferior parietal lobe compared to SM and CM; whereas the CM group had higher activation of the superior parietal gyrus than the TM and SM ones. Conclusion(s): Both the modalities of administration (observation vs observation and execution) and the type of task (simple, complex or transitive) modulate MNS recruitment. Implications: In recent years, action observation (AO) namely the imitation ofmovement after their observation, has become a valuable tool for relearning motor tasks in rehabilitation approaches. The best strategy for AO administration is still an open question. It is reasonable to speculate that AO characteristics should also depend from the location of central nervous system (CNS) lesions. This study provides some novel pieces of information for planning AO strategies in subjects with CNS lesions.

Freely Chosen Index Finger Tapping Frequency Is Increased in Repeated Bouts of Tapping

ABSTRACTHealthy individuals (n = 40) performed index finger tapping at freely chosen frequency during repeated bouts and before and after near-maximal muscle action consisting of 3 intense flexions of the index finger metacarpal phalangeal joint. One experiment showed, unexpectedly, that a bout of tapping increased the tapping frequency in the subsequent bout. Thus, a cumulating increase of 8.2 ± 5.4% (p < .001) occurred across 4 bouts, which were all separated by 10 min rest periods. Follow-up experiments revealed that tapping frequency was still increased in consecutive bouts when rest periods were extended to 20 min. Besides, near-maximal muscle activation, followed by 5 min rest, did not affect the tapping frequency. In conclusion, freely chosen tapping frequency was increased in repeated bouts of tapping, which were separated by 10–20 min rest periods. The observed phenomenon is suggested to be termed repeated bout rate enhancement.