Weber (Slope) Analyses of Timing Variability in Tapping and Drawing Tasks

Handwriting: Hand–pen contact force synergies in circle drawing tasks

Dual task performance in children: Generalized and lateralized effects of memory encoding upon the rate and variability of concurrent finger tapping

The influence of dominant versus non-dominant hand on event and emergent motor timing

This paper investigates how visual cues affect human performance at a line drawing task. Line drawing is a primitive and fundamental task using tools such as pens, (soldering) irons, and cutters. Many situations (for example, home, office, studio, and workshop) require drawing lines with tools. Assistive tools for improving performance might be especially useful for unskilled people. As a first step, we focus on visual cues as assistive tools and determine the kinds of visual cues that are effective for good performance. We asked subjects to draw a line on a displayed dotted line while the spacing and shape of the dots is changed, and we then analyzed the data. The results indicate that the cue that should be displayed for good performance should change according to subjects' performance: for good performers the cue whose geometrical center is easy to detect, and for not-good performers the cues whose occupied area is large. We also discussed the possibility of controlling performance in line drawing, and presented a strategy for displaying visual cues for good line drawing performance.

The Wing-Kristofferson (WK) model of movement timing emphasises the separation of central timer and motor processes. Several studies of repetitive timing have shown that increase in variability at longer intervals is attributable to timer processes; however, relatively little is known about the way motor aspects of timing are affected by task movement constraints. In the present study, we examined timing variability in finger tapping with differences in interval to assess central timer effects, and with differences in movement amplitude to assess motor implementation effects. Then, we investigated whether effects of motor timing observed at the point of response (flexion offset/tap) are also evident in extension, which would suggest that both phases are subject to timing control. Eleven participants performed bimanual simultaneous tapping, at two target intervals (400, 600 ms) with the index finger of each hand performing movements of equal (3 or 6 cm) or unequal amplitude (left hand 3, right hand 6 cm and vice versa). As expected, timer variability increased with the mean interval but showed only small, non-systematic effects with changes in movement amplitude. Motor implementation variability was greater in unequal amplitude conditions. The same pattern of motor variability was observed both at flexion and extension phases of movement. These results suggest that intervals are generated by a central timer, triggering a series of events at the motor output level including flexion and the following extension, which are explicitly represented in the timing system.

There is increasing evidence that the cerebellum has a role in the pathophysiology of primary focal hand dystonia and might provide an intervention target for non-invasive brain stimulation to improve function of the affected hand. The primary objective of this study was to determine if cerebellar transcranial direct current stimulation (tDCS) improves handwriting and cyclic drawing kinematics in people with hand dystonia, by reducing cerebellar-brain inhibition (CBI) evoked by transcranial magnetic stimulation (TMS). Eight people with dystonia (5 writer’s dystonia, 3 musician’s dystonia) and eight age-matched controls completed the study and underwent cerebellar anodal, cathodal and sham tDCS in separate sessions. Dystonia severity was assessed using the Writer’s Cramp Rating Scale (WRCS) and the Arm Dystonia Disability Scale (ADDS). The kinematic measures that differentiated the groups were; mean stroke frequency during handwriting and fast cyclic drawing and average pen pressure during light cyclic drawing. TMS measures of cortical excitability were no different between people with FHD and controls. There was a moderate, negative relationship between TMS-evoked CBI at baseline and the WRCS in dystonia. Anodal cerebellar tDCS reduced handwriting mean stroke frequency and average pen pressure, and increased speed and reduced pen pressure during fast cyclic drawing. Kinematic measures were not associated with a decrease in CBI within an individual. In conclusion, cerebellar anodal tDCS appeared to improve kinematics of handwriting and circle drawing tasks; but the underlying neurophysiological mechanism remains uncertain. A study in a larger homogeneous population is needed to further investigate the possible therapeutic benefit of cerebellar tDCS in dystonia.

The current study aimed to investigate the impact of recreational gymnastics on executive function in Chinese preschoolers, with a focus on gymnastics potential to enhance core components of executive function. A total of 63 preschool children who received full-time education were randomly assigned to either an intervention group (N = 31, mean age = 66.27 months, SD = 3.12 months) or a control group (N = 32, mean age = 66.79 months, SD = 3.34 months). The intervention group engaged in recreational gymnastics for 60 min, three times a week for 12 weeks. Meanwhile, the control group continued with their typical outdoor activities at kindergarten and did not participate in any organized sports. The intervention program was primarily conducted through group play and was facilitated by teachers who underwent standardized training. Various simple and complex tasks were utilized to evaluate delay gratification (Snack delay and Wrapped gift), inhibitory control (Stop signal task and Circle drawing task), working memory (Letter memory task and Keep track task), and cognitive flexibility (Go/No-Go task and Dots task). The analysis of covariance revealed that the children who participated in the intervention outperformed the control group on most simple and complex executive function tasks. Specifically, these children demonstrated an enhanced ability to regulate persistent responses, process and update information, and manage high cognitive conflict. The findings of this investigation lend support to the hypothesis that moderate-intensity recreational gymnastics is an efficacious means of enhancing executive function in early childhood. Future research should employ a larger sample size, incorporate a long-term follow-up design, and utilize a multi-method approach to further substantiate the impact of moderate-intensity gymnastics on the executive function of young children, as well as to investigate its underlying mechanism and generalizability.

Sensorimotor timing deficits are considered central to attention-deficit/hyperactivity disorder (ADHD). However, the tasks establishing timing impairments often involve interconnected processes, including low-level sensorimotor timing and higher level executive processes such as attention. Thus, the source of timing deficits in ADHD remains unclear. Low-level sensorimotor timing can be isolated from higher level processes in a finger-tapping task that examines the motor response to unexpected shifts of metronome onsets. In this study, adults with ADHD and ADHD-like symptoms (n=25) and controls (n=26) performed two finger-tapping tasks. The first assessed tapping variability in a standard tapping task (metronome-paced and unpaced). In the other task, participants tapped along with a metronome that contained unexpected shifts (±15, 50ms); the timing adjustment on the tap following the shift captures pre-attentive sensorimotor timing (i.e., phase correction) and thus should be free of potential higher order confounds (e.g., attention). In the standard tapping task, as expected, the ADHD group had higher timing variability in both paced and unpaced tappings. However, in the pre-attentive task, performance did not differ between the ADHD and control groups. Together, results suggest that low-level sensorimotor timing and phase correction are largely preserved in ADHD and that some timing impairments observed in ADHD may stem from higher level factors (such as sustained attention).

Comfortable synchronization of cyclic drawing movements with a metronome

IntroductionPrevious transcranial magnetic stimulation (TMS) studies have revealed that the activity of the primary motor cortex ipsilateral to an active hand (ipsi-M1) plays an important role in motor control. The aim of this study was to investigate whether the ipsi-M1 excitability would be influenced by goal-directed movement and laterality during unilateral finger movements.MethodTen healthy right-handed subjects performed four finger tapping tasks with the index finger: (1) simple tapping (Tap) task, (2) Real-word task, (3) Pseudoword task, and (4) Visually guided tapping (VT) task. In the Tap task, the subject performed self-paced simple tapping on a touch screen. In the real-word task, the subject tapped letters displayed on the screen one by one to create a Real-word (e.g., apple). Because the action had a specific purpose (i.e., creating a word), this task was considered to be goal-directed as compared to the Tap task. In the Pseudoword task, the subject tapped the letters to create a pseudoword (e.g., gdiok) in the same manner as in the Real-word task; however, the word was less meaningful. In the VT task, the subject was required to touch a series of illuminated buttons. This task was considered to be less goal-directed than the Pseudoword task. The tasks were performed with the right and left hand, and a rest condition was added as control. Single- and paired-pulse TMS were applied to the ipsi-M1 to measure corticospinal excitability and short- and long-interval intracortical inhibition (SICI and LICI) in the resting first dorsal interosseous (FDI) muscle.ResultsWe found the smaller SICI in the ipsi-M1 during the VT task compared with the resting condition. Further, both SICI and LICI were smaller in the right than in the left M1, regardless of the task conditions.DiscussionWe found that SICI in the ipsi-M1 is smaller during visual illumination-guided finger movement than during the resting condition. Our finding provides basic data for designing a rehabilitation program that modulates the M1 ipsilateral to the moving limb, for example, for post-stroke patients with severe hemiparesis.

In this paper we propose a methodology for objective evaluation and classification of repetitive finger tapping performance based solely on its spectral behavior. We used miniature sensor system with gyroscope placed over fingertip of index finger for finger tapping recording. The study included 20 subjects - 10 patients with Parkinson's disease (PD) and 10 age and gender matched healthy controls. Acquired data were preprocessed using continuous wavelet transformation (CWT), and their coefficients were used in further analysis. Based on cross-sections of CWT in time and frequency, we introduced parameters describing characteristic tapping frequencies and vigor of the performed movements, its decrement and isolated characteristic frequency areas. These parameters were further used in classification for distinction between PD patients and controls, achieving 95% classification accuracy.

Circle drawing may be a useful task to study upper-limb function in patient populations. However, previous studies rely on expensive and bulky robotics to measure performance. For clinics or hospitals with limited budgets and space, this may be unfeasible. Virtual reality (VR) provides a portable and low-cost tool with integrated motion capture. It offers potentially a more feasible medium by which to assess upper-limb motor function. Prior to use with patient populations, it is important to validate and test the capabilities of VR with healthy users. This study examined whether a VR-based circle drawing task, completed remotely using participant’s own devices, could capture differences between movement kinematics of the dominant and non-dominant hands in healthy individuals. Participants (n = 47) traced the outline of a circle presented on their VR head-mounted displays with each hand, while the positions of the hand-held controllers were continuously recorded. Although there were no differences observed in the size or roundness of circles drawn with each hand, consistent with prior literature our results did show that the circles drawn with the dominant hand were completed faster than those with the non-dominant hand. This provides preliminary evidence that a VR-based circle drawing task may be a feasible method for detecting subtle differences in function in clinical populations.

Brain activation during finger tapping and circle-drawing tasks measured by functional near-infrared spectroscopy (fNIRS)

In separate experiments, we studied the temporal accuracy and precision of self-paced, repetitive finger-tapping in two groups of 12 patients with Parkinson's disease and a group of 12 controls matched to the patients with respect to age and general cognitive state. One group (I) of patients was studied initially following 12-15 h abstinence from normal levodopa medication ('off') and again, subsequently, approximately 1 h after ingestion of a single normal dose ('on'). A second group (II) of patients, each of whom had bilaterally asymmetrical neurological signs, was tested using 'worse' and 'better' hands separately. Within each session, subjects were tested repeatedly on a tapping task during which they were required to produce a regular series of self-timed inter-tap intervals, the target duration (550 ms) of which had been established previously during an initial period of tapping in synchrony with the beats of a regular metronome. We employed Wing and Kristofferson's (1973) model of control of motor timing to partition the total variance (TV) about the mean inter-response interval (IRI) produced during the self-paced phase of each run into separate components ['clock' variance (CV) and 'motor-delay' variance (MDV)] attributable to hypothetical 'clock' and 'motor-implementation' processes. Although the mean self-paced IRI of parkinsonian patients was generally shorter than that of controls, only during the 'on' medication condition (Group I) was it significantly so. By comparison with control values, and those observed during the 'on' medication condition, values of TV, CV and MDV in Group I were all significantly higher when subjects were 'off' medication. During the 'on' medication condition, only CV was significantly higher than the control value. In Group II, values of TV, CV and MDV associated with use of the 'worse' hand were all significantly higher than both control values and those associated with use of the 'better' hand. Values of these variables when subjects used the 'better' hand did not, however, differ significantly from control values. The theoretical import of these results is discussed in the light of several important procedural, statistical and computational issues and we conclude that TV, CV, and MDV may all vary significantly as a function of the efficacy of dopaminergic transmission in the basal ganglia.

Circle drawing and tracing dataset for evaluation of fine motor control