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Handwriting difficulties are common in children with Attention-Deficit/Hyperactivity Disorder (ADHD), and they have been associated with lower academic achievement and self-esteem. Our aim in this study was to determine if training coordination of the head, eyes, and arm and engaging in the necessary visual concentration associated with table tennis would improve executive functions and school-based handwriting among children with ADHD. We designed a randomized controlled trial to explore the therapeutic efficacy of this table tennis training and recruited 48 children with ADHD that we randomly assigned to one of three equal-sized training groups: (a) actual table tennis, (b) simulated table tennis (exergame), or (c) a control group receiving no additional training. The training intervention lasted 12-weeks in which the two different table tennis trainings (i.e., actual or simulated) were scheduled for three one-hour sessions per week. Outcome measures included a computerized handwriting evaluation, the Stroop test, and the Wisconsin Card Sorting Test (WCST). Participants in each table tennis training group showed significant improvements in handwriting performance, response time, and required time to achieve automation. Both intervention groups also showed significant improvements on the Stroop Color-Word test, but only the actual table tennis training group showed a significant improvement on the WCST. This study provided evidence of at least short-term improvements in executive functions and handwriting problems in children with ADHD through their participation in table tennis motor coordination activities.

In this paper, we introduce a newly developed multi-scale wavelet model for the interpretation of surface electromyography (SEMG) signals and validate the model’s capability to characterize changes in neuromuscular activation in cases with myofascial pain syndrome (MPS) via machine learning methods. The SEMG data collected from normal (N = 30; 27 women, 3 men) and MPS subjects (N = 26; 22 women, 4 men) were adopted for this retrospective analysis. SMEGs were measured from the taut-band loci on both sides of the trapezius muscle on the upper back while he/she conducted a cyclic bilateral backward shoulder extension movement within 1 min. Classification accuracy of the SEMG model to differentiate MPS patients from normal subjects was 77% using template matching and 60% using K-means clustering. Classification consistency between the two machine learning methods was 87% in the normal group and 93% in the MPS group. The 2D feature graphs derived from the proposed multi-scale model revealed distinct patterns between normal subjects and MPS patients. The classification consistency using template matching and K-means clustering suggests the potential of using the proposed model to characterize interference pattern changes induced by MPS.

This study examined the psychometric properties of motor praxis using a large school-based sample of children (n = 239). We developed and evaluated the construct validity of a motor praxis assessment using confirmatory factor analysis (CFA). A model with four latent variables was evaluated for goodness of fit. CFA established that the scale was multifactorial and supported the four-factor model (motor imagery, verbal gesture production, imitative gesture production and knowledge of object-use). The internal consistency, inter-rater reliability and concurrent validity of the praxis assessment mostly demonstrated good to excellent results for the full scale and the subscales. The motor praxis demonstrated an ontogenic progression in 6-, 7- and 8-year-olds, suggesting a developmental trend during these ages, but with the exception of gestural representation on imitation. Implications for motor development and clinical evaluation are discussed herein in relation to the four instruments.

The aim of this study was to determine an appropriate frequency and location of binaural electrostimulation to ensure the treatment effect. Twenty-three healthy participants were recruited to receive 15 min of electrostimulation at two different frequencies (i.e., 1 vs. 25 Hz), and the same procedure was performed at two locations (tragus vs. earlobe). This study observed fluctuations in heart rate variability to reflect the autonomic activity. Repeated measures ANOVA was carried out to determine the differences. Results showed that the activities of parasympathetic and total power increased after stimulation in both tragus and earlobe trials. However, the effect of 25 Hz stimulation to increase total power was significantly higher than that of 1 Hz. No significant difference in stimulating the earlobes or tragus was observed. Therefore, binaural electrostimulation might be cardioprotective and useful as a complement to medical treatment.

Background: People experiencing strong feelings of fatigue during exercise sometimes subconsciously yell to refocus their efforts and, thus, maintain exercise performance. The present study examined the influence of yelling during high-intensity exercise by analysing cardiorespiratory reactions and integrated electromyography (iEMG) changes in the vastus lateralis during a cycle ergometer test. Methods: A total of 23 moderately trained people were recruited. The cycling test began with a resistance of 25 W/min, which was gradually increased. During the experimental trial, the participants were required to yell at least 3 times when they felt exhausted; during the controlled trial, they were not allowed to produce any yelling sounds. The testing order was randomly assigned and the 2 trials were completed within an interval between 3–10 days. Two-way repeated measures ANOVA was applied to analyse the differences within and between the trials, and interaction of trial and time. Results: The peak power and time to exhaustion (p

In this study, we explored the relationship between the clinical features and motor impairments related to the graphomotor function of individuals with Parkinson's disease (PD) and essential tremor (ET). We recruited 46 participants: 12 with PD, 13 with ET, and 21 controls. All participants were asked to perform six graphomotor tasks on a digitizer tablet: drawing straight lines, cursive-connected loops, discrete circles, and continuous circles, and making goal-aimed movements with a stylus in two different directions with three different accuracy constraints. The results showed that although participants with PD were able to draw straight lines slightly faster than controls, they produced cursive-connected loops much slower than controls. In addition, in contrast to controls and individuals with ET, PDs also drew the cursive loops progressively smaller. In the aiming task, we found that equivalent movements with high accuracy constraints were drawn slower by individuals with ET or PD than by controls. However, when performing the equivalent movements with moderate or low accuracy constraints, PDs performed similarly to controls. In contrast to the equivalent movements, PD and ET participants both performed nonequivalent movements slower than controls, no matter the demands arising from the accuracy constraints. The present study shows that simple graphic tasks can differentiate impairments in fine motor function resulting from ET and PD.

Since wrist-joint position affects finger muscle length and grip strength, we studied its biomechanical relevance in prolonged handwriting. We recruited participants from young adults, aged 18–24, and separated them into control ( n = 22) and in-pain ( n = 18) groups, based whether or not they experience pain while handwriting. The participants then performed a writing task for 30 min on a computerized system which measured their wrist-joint angle and documented their handwriting kinematics. The in-pain group perceived more soreness and had a less-extended wrist joint, longer on-paper time, and slower stroke velocity compared to control group. There was no significant difference in handwriting speed and quality between the two groups. The wrist extension angle significantly correlated with perceived soreness. Ergonomic and biomechanical analyses provide important information about the handwriting process. Knowledge of pen tip movement kinematics and wrist-joint position can help occupational therapists plan treatment for individuals with handwriting induced pain.

This study proposed a new technology to assess the accuracy of Chinese handwriting by comparing every stroke movement between a template model and a handwritten script. It tested the feasibility of a computerized evaluation in the parameterization of the handwriting deterioration caused by impaired cognitive function. This study recruited 22 participants with Alzheimer's disease (AD) and 14 with amnestic mild cognitive impairment (aMCI); 18 age- and gender-matched healthy elderly individuals made up the health control. The graphomotor tasks included drawing four straight lines (vertical, horizontal, and two diagonal) as well as writing Chinese words with simple vertical, horizontal and diagonal strokes. The temporal and spatial data were calculated to measure the motor coordination. The results in geographic drawing tests reveal significant differences among the three groups in task accuracy and movement fluency, especially in nonequivalent and wrist movements. The accuracy control of the graphic drawing in the AD and aMCI groups was significantly lower than that for the subjects in the normal group. These two groups also showed longer pauses in stroke movement with the handwriting tasks. The handwriting accuracy in the AD and aMCI groups was found to be significantly different from that of the subjects in the normal group. The results of this study can be used as an indicative reference for early detection of AD or aMCI, an objective evaluation for the effectiveness of interventions, and an assessment of disease progression.

The objective of this study was to compare the effect of computer-assisted practice with the sensorimotor approach on the remediation of handwriting problems in children with dysgraphia. In a randomized controlled trial, experiments were conducted to verify the intervention effect. Forty two children with handwriting deficit were assigned to computer-assisted instruction, sensorimotor training, or a control group. Handwriting performance was measured using the elementary reading/writing test and computerized handwriting evaluation before and after 6 weeks of intervention. Repeated-measures ANOVA of changed scores were conducted to show whether statistically significant differences across the three groups were present. Significant differences in the elementary reading/writing test were found among the three groups. The computer group showed more significant improvements than the other two groups did. In the kinematic and kinetic analyses, the computer group showed promising results in the remediation of handwriting speed and fluency. This study provided clinical evidence for applying a computer-assisted handwriting program for children with dysgraphia. Clinicians and school teachers are provided with a systematic intervention for the improvement of handwriting difficulties.

Dysgraphia of sufficient severity to interfere with the school work has been recognized as representing a distinct deficit; characterization of its movement problem is a necessary step toward offering improved intervention. From among children aged 6-8, 69 children with dysgraphic characteristics (study group) and 69 matched proficient hand-writers (control group) were recruited into this study. Four copying tests of differing complexity levels were administered using a digital tablet. The acquired data included direct measure (axial pen tip force) and derived parameters (stroke velocity, pause time, number of velocity peaks and ratio of In Air to On Paper measures). The major finding is that children with dysgraphic characteristics had increased pause time per stroke and an increased number of directional changes in velocity. Significant differences were also found between students in two different grades, especially in the control group. The parameters extracted and observed in this study can further differentiate and characterize the handwriting problems originating from fine motor deficits.

To solve the limitations in using the conventional parametric measures to define myofascial pain, a 3-D multi-scale wavelet energy variation graph is proposed as a way to inspect the pattern of surface electromyography (SEMG) variation between the dominant and nondominant sides at different frequency scales during a muscle contraction cycle and the associated changes with the upper-back myofascial pain. The model was developed based on the property of the wavelet energy of the SEMG signal revealing the degree of correspondence between the shape of the motor unit action potential and the wavelet waveform at a certain scale in terms of the frequency band. The characteristic pattern of the graph for each group (30 normal and 26 patient subjects) was first derived and revealed the dominant-hand effect and the changes with myofascial pain. Through comparison of individual graphs across subjects, we found that the graph pattern reveals a sensitivity of 53.85% at a specificity of 83.33% in the identification of myofascial pain. The changes in these patterns provide insight into the transformation between different fiber recruitment, which cannot be explored using conventional SEMG features. Therefore, this multi-scale analysis model could provide a reliable SEMG features to identify myofascial pain.

Aim The purpose of this study was to characterize handwriting deficits in children with developmental coordination disorder (DCD) using computerized movement analyses. Method Seventy-two children (40 females, 32 males; mean age 7y, SD 7mo; range 6y 2mo to 7y 11mo) with handwriting deficits (33 with DCD, 39 without DCD); and 22 age- and sex-matched children without handwriting deficits were asked to perform handwriting tasks on a digital tablet for the collection of kinematic and kinetic data. Practice times required to achieve automation of movement when writing an unfamiliar character were used to assess the motor learning of handwriting. The children were asked to copy three simple and three complex characters, and the velocity and axial pen force used for corresponding strokes were compared. Results The attainment of automated handwriting was markedly slower in children with handwriting deficits and DCD, who used a faster stroke velocity to write simple characters (1.22 times those without handwriting deficits), but when writing complex characters, their stroke velocity and pen force were lower (0.85 and 0.89 times those without handwriting deficits, respectively). Interpretation By linking the results with neuromotor control theories, it was determined that children with DCD have difficulties performing the open-loop and closed-loop movements required for fluent handwriting.

To examine the discriminant validity of the Visual Motor Integration test in screening children with handwriting dysfunction, 599 children in Grade 2, including 41 children with handwriting dysfunction identified by their teachers and 558 typically developing children, were assessed. The Visual Motor Integration test, with an area under the receiver operating characteristic curve (0.894), showed high accuracy regarding screening purposes. Judging from the values for sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, hit rate, Youden's index, and odds ratio, a standard score of 85 was the best cutoff point for screening children for handwriting dysfunction.

This paper describes a pilot study investigating an assessment for Chinese handwriting performance. In an attempt to computerize the existing Tseng Handwriting Problem Checklist (Tseng Checklist), this study employed MATLAB to develop a computer program entitled the Chinese Handwriting Assessment Program (CHAP) to be used for the evaluation of handwriting performance. Through a template-matching approach, the program processed each character by using size-adjustable standard models to calculate the two-dimensional cross-correlation coefficient of a template and a superimposed handwritten character. The program measured the size control, spacing, alignment, and the average resemblance between standard models and handwritten characters. The results of the CHAP's test-retest reliability showed that the high correlation coefficients (from .81 to .94) were statistically significant. Correlations between each CHAP and Tseng Checklist item were statistically significant. As these assessment tools for handwriting performance are required for quantitative and qualitative aspects, the integration of the two tools is a promising means for accomplishing a handwriting performance assessment.

The praxis test is a less well-documented method to determine functional manifestations of childhood dyspraxia. For this study, children aged 6-8years were recruited as follows: 17 children with DCD, 18 at risk of DCD and 35 without obvious problems in motor coordination. The Movement Assessment Battery for Children (MABC-2) was used to measure motor performance and identify the motor incoordination. This study developed a battery of tests to assess limb praxis using a praxis imagery questionnaire, gesture representation, and questions about knowledge of object use. In the comparison of subtests within the praxis test, significant differences were observed across groups on the praxis imagery questionnaire and gesture representation tests but not on knowledge of object use. Similar results were observed in the correlation analyses, in which a weak relationship between MABC-2 and praxis tests was observed. The DCD group had lower scores on the praxis imagery questionnaire, whereas the group at risk of DCD had lower scores on most gesture production tests. Our study provides a better understanding of the nature of the childhood dyspraxia and sheds light on its effect on motor coordination to identify praxis tests with specific clinical meanings in children with movement disorders.

This study compares the amplitude and temporal features of stimulus-evoked electromyography (EMG) of paralyzed muscle, rectus femoris (RF), in both lengthened and shortened positions of six spinal cord injured (SCI) subjects during an electrically elicited fatigue process. The torque output and evoked EMG were fitted by hyperbolic tangent functions from which their amplitude residual levels and temporal inflection times can be extracted. Furthermore, a structural EMG model of Fuglevand et al (1992 Biol. Cybern. 67 143-53) was modified to include type I (slow twitch) and type II (fast twitch) of motor unit (MU) fibers with viable parameters obtained from paralyzed muscles to observe their amplitude and temporal changes. Our results showed that the amplitude of stimulus-evoked EMG decreased earlier in the lengthened muscle with a shorter inflection time (48.53 +/- 8.7 s versus 55.13 +/- 4.03 s) than that of the shortened position during 120 s of stimulation time (p0.05). Similarly, the peak-to-peak duration (PTPd) of the evoked EMG increased faster at an earlier time to a higher asymptotical value in lengthened muscle (2.23 +/- 0.74 versus 1.77 +/- 0.54), compared to that of a shortened one (p0.05). These observations coincided with the higher rising rate and larger final value of the temporal coefficients, i.e., longer duration, in both type I and II MUs of lengthened muscles. From the observation of all parameters, the fatigue process in lengthened muscle proceeds faster than that in shortened muscle.

This study developed a functional cycling system for home use by paraplegics. It is a hybrid system with functional electrical stimulation (FES). In an earlier study, three tasks were completed: (1) determine user needs and potential problems in interface design, (2) interviews with therapists, and (3) questionnaires to the patients. These findings were converted to functional elements (for design of the FES cycling ergometer) and design criteria (for evaluation of the FES-cycling device). The FES device has both hardware and software features. Hardware includes: arm-crank, leg-cycling, guarded thigh holders, protective paddleboard, easy-access battery box and easy wheelchair height adjustment. The wheelchair can roll into a U-shaped track so the patient can exercise while in the wheelchair. A pocket PC-based controller was used for stimulation control of the patient and data acquisition. A better controller was used to adjust the stimulation based on a pre-defined stimulation pattern. The data recorded was wired to a clinic for evaluation of cycling smoothness as well as to redesign the training protocol. Relevance to industry FES has demonstrated many physiological and psychological benefits for patients with spinal cord injuries. This study offers an improved design of the FES-cycling system, including hybrid exercise modes, an improved controller and wireless transmission of data and training protocol, all of which can be used at home to better serve patients with paraplegia.

We investigated a visual–perceptual and haptic–perceptual training program to enhance motor skills and Chinese handwriting performance among children with handwriting difficulties. The participants were 28 first- and second-grade children with handwriting difficulties. They were matched according to age and then randomly assigned into a control group or an experimental group. Participants in the experimental group received 12 sessions of a training program, whereas those in the control group received conventional handwriting training. The Test of Visual Perceptual Skills—Third Edition (TVPS–3), Tactual Performance Test (TPT), and Battery of Chinese Basic Literacy (BCBL) were all administered before and after 6 wk of intervention. Repeated-measures analysis of variance revealed that the experimental group showed significant improvement on the TVPS–3 but not on the TPT. Along with the improved visual–perceptual skills, the experimental group showed a significant difference in far-point copy speed and handwriting accuracy, as reflected in the BCBL.

Functional electrical stimulation (FES) standing system can enable the paraplegics to achieve the standing position for functional activities in daily living. FES standing system is usually applied by stimulating the knee extensor muscles. The hip joints are in hyperextension and the ankle joints remain free. Therefore, the knee joint control is the key point of the FES standing control system. Traditional open-loop control often induces high knee end-velocity (KEV) when the subject reaches the upright position. In this work, the reducing of KEV by closed-loop control was addressed. An on/off feedback control based on mechanical energy conservation was developed to control the knee extensors and flexors. The result was compared to the open loop controlled standing up in a mechanically simulative experiment. It is concluded that the on/off control strategy can reduce the KEV more efficiently when compared to the open-loop control. Proportional-integral-derivative (PID) position controlled standing up was also studied and compared with the on/off control system. The PID controller was found to be capable of reducing KEV to a level lower than that of the on/off control, whereas its instability for knee control was also found.

The fatigue characteristics of paralyzed muscles were investigated during dynamic cycling movement induced by functional electrical stimulation (FES). The peak-to-peak (PTP) amplitude of stimulus-evoked electromyogram (EMG), after suppression of stimulus artifact, was adopted as fatigue indicator. Compared to static contraction, the effects of dynamic movement factors on the stimulus-evoked EMG, such as the intermittent stimulation, joint angle, and contraction speed, were first evaluated in separate experiments. The results of isolated tests laid the foundation for interpreting the data obtained in two FES-cycling experiments, performed under maximum stimulation or in controlled cycling speeds. The effects of intermittent stimulation and joint angle caused periodic changes in PTP amplitude which can be alleviated by averaging the PTP amplitude of one cycle. Under the same stimulation intensity, the authors' results indicated that slower muscle contraction speed would have larger PTP amplitude and vice versa. For the limited number of subjects with paraplegia studied, the authors' results showed that the use of EMG PTP as reliable muscle fatigue indicator during dynamic movement is only valid at the same cycling speed or corresponding contraction speed. The decline of the PTP amplitude decreased with the decay of muscle force can be observed during cycling movement; however, reduction of cycling speed had the opposite effect on PTP amplitude. Observations from the hyperbolic modeling of fatigue process demonstrated that the EMG PTP of a fatigued muscle under dynamic movement decreased at a slower rate.

The objective of this study was to test how advanced digital technology enables a more effective training on the handwriting of children with handwriting deficit. This study implemented the graphomotor apparatuses to a computer-assisted instruction system. In a randomized controlled trial, the experiments for verifying the intervention effect were conducted. Forty two children with handwriting deficit were assigned to computer-assisted instruction, sensorimotor training or control (no intervention) group. Handwriting performance was measured using the Elementary reading/writing test and computerized handwriting evaluation before and after 6 weeks of intervention. Analysis of variance of change scores were conducted to show whether statistically significant difference across the three groups. Significant difference was found among three groups. Computer group shows significant difference from the other two groups. Significance was denoted in near-point, far-point copy, dictation test, and writing from phonetic symbols. Writing speed and mean stroke velocity in near-, far-point and short paragraph copy were found significantly difference among three groups. Computer group shows significant improvement from the other groups. For clinicians and school teachers, the results of this study provide a motor control based insight for the improvement of handwriting difficulties., {"references":["I. Phelps, L. Stemple, & G. Speck, G. \"The children's handwriting scale: \nA new diagnostic scale\", Journal of Educational Research, vol. 79, pp. \n46-50, 1985.","M. J. Weil & S. J. C. Amundson, \"Relationships between visuomotor and \nhandwriting skills of children in kindergarten. American Journal of \nOccupational Therapy, vol. 48, pp. 982-988, 1994.","K. McHale & S. A. Cermak, \"Fine motor activities in elementary school: \npreliminary findings and provisional implications for children with fine \nmotor problems\", American Journal of Occupational Therapy, vol. 46, pp. \n898-903, 1992.","M. H. Tseng & S. A. Cermak, \"The influence of ergonomic factors and \nperceptual-motor abilities on handwriting performance\", American \nJournal of Occupational Therapy, vol. 47, pp. 919-926, 1993.","M. H. Tseng & E. A. Murray, \"Differences in perceptual-motor measures \nbetween good and poor writers. American Journal of Occupational \nTherapy, vol. 14, 19-36, 1994.","M. J. M. Volman, B. M. Van Schendel, M. J. Jongmans, \"Handwriting \ndifficulties in primary school children: a search for underlying \nmechanisms. American Journal of Occupational Therapy, vol. 60, pp. \n451-460, 2006.","M. D. Levine, F. Oberklaid, & L. Meltzer, \"Developmental output failure: \nA study of low productivity in school-based children\", Pediatrics, vol. 67, \npp. 18-25, 1981.","J. I. Laszlo & P. J. Bairstow, \"Handwriting difficulties and possible \nsolutions\", School Psychology International, vol. 5, pp. 207-213, 1984.","P. Sudsawad, C. A. Trombly, A. Henderson, & L. Tickle-Degnen, \n\"Testing the effect of kinesthetic training on handwriting performance in \nfirst-grade students\", Am J Occup Ther, vol. 56, pp. 26-33, 2002. \n[10] R. Karlsdottir & T. Stefansson, \"Problems in developing functional \nhandwriting\", Percept Mot Skills, vol. 94, pp. 623-662, 2002. \n[11] M. J. Jongmans, E. Linthorst-Bakker, Y. Westenberg, B. C. M. \nSmits-Engelsman, \"Use of a task-oriented self-instruction method to \nsupport children in primary school with poor handwriting quality and \nspeed\", Hum Mov Sci, vol. 22, pp. 549–566, 2003. \n[12] M. Lally, \"Computer-assisted handwriting instruction and \nvisual/kinaesthetic feedback processes\", Applied Research in Mental \nRetardation, vol. 3, no. 4, pp. 397-405, 1982. \n[13] P. L. Denton, S. Cope, & C. Moser, C. \"The effect of Sensorimotor-Based \nintervention versus Therapeutic practice on improving handwriting \nperformance in 6- to 11-year-old Children\", Am J Occup Ther, vol. 60, pp. \n16-27, 2006. \n[14] S. H. Chang & N. Y. Yu, \"Evaluation and classification of types of \nChinese handwriting deficits in elementary schoolchildren\", Perceptual \nand Motor Skills, 101, 631-647, 2005. \n[15] L. Hung, Y. W. Chang, S. F. Chen, C. S. Chen, & Y. D. Lee, Elementary \nReading and Writing test, Taipei: Psychological Co., Taipei, 2003. \n[16] G. P. van Galen, S. J. Portier, B. C. M. Smits-Engelsman, & L. R. \nSchomaker, \"Neuromotor noise and poor handwriting in children\", Acta \nPsychol, vol. 82, pp. 161-178, 1993. \n[17] B. C. M. Smits-Engelsman, A. S. Niemeijer, & G. P. van Galen, \"Fine \nmotor deficiencies in children diagnosed as DCD based on poor \ngrapho-motor ability\", Human Movement Science, vol. 20, pp. 161-182, \n2001. \n[18] S. H. Chang & N. Y. Yu, \"Characterization of motor control in handwriting difficulties in children with or without developmental \ncoordination disorder\", Developmental Medicine & Child Neurology, vol. \n52, no. 3, pp. 244-250, 2010. \n[19] S. Rosenblum & M. Livneh-Zirinski, \"Handwriting process and product \ncharacteristics of children diagnosed with developmental coordination \ndisorder\", Hum Mov Sci, vol. 27, pp. 200-214, 2008."]}

This study explores the clinical features of neurodegenerative disease patients with tremor. We study the motor impairments in patients with Parkinson’s disease (PD) and essential tremor (ET). Since uncertainty exists on whether Parkinson's disease (PD) and essential tremor (ET) patients have similar degree of impairment during motor tasks, this study based on the self-developed computerized handwriting movement analysis to characterize motor functions of these two impairments. The recruited subjects were diagnosed and confirmed one of neurodegenerative diseases. They were undergone general clinical evaluations by physicians in the first year. We recruited 8 participants with PD and 10 with ET. Additional 12 participants without any neuromuscular dysfunction were recruited as control group. This study used fine motor control of penmanship on digital tablet for sensorimotor function tests. The movement speed in PD/ET group is found significant slower than subjects in normal control group. In movement intensity and speed, the result found subject with ET has similar clinical feature with PD subjects. The ET group shows smaller and slower movements than control group but not to the same extent as PD group. The results of this study contribute to the early screening and detection of diseases and the evaluation of disease progression., {"references":["E. D. Louis, \"Essential tremor\". Lancet Neurol, vol. 4, pp.100-110, 2005.","E. D. Louis, G. Levy, L. J. Cote, H. Mejia, S. Fahn S, and K. Marder, \n\"Clinical correlates of action tremor in Parkinson disease\", Arch \nNeurol,vol. 58, pp. 1630-1634, 2001.","R. J. Elble, \"Essential tremor is a monosymptomatic disorder\", Mov \nDisord, vol. 17, pp. 633-637, 2002.","J. Jankovic, \"Essential tremor: a heterogenous disorder\", Mov Disord, vol. \n17, pp. 638-644, 2002.","R. J. Elble, C. Higgins, and L. Hughes, \"Essential tremor entrains rapid \nvoluntary movements. Exp Neurol, vol. 126, pp. 138-143, 1994.","S. Ozekmekci, G. Kiziltan, M. Vural, S. Ertan, H. Apaydin, and E. \nErginoz, \"Assessment of movement time in patients with essential tremor. \nJ Neurol, vol. 252, pp. 964-967, 2005.","E. B. Montgomery, Jr, K. B. Baker, K. Lyons, and W. C. Koller, \"Motor \ninitiation and execution in essential tremor and Parkinson's disease\", Mov \nDisord, vol. 15, pp. 511-515, 2000.","C. Duval, A. F. Sadikot, and M. Panisset, \"Bradykinesia in patients with \nessential tremor\", Brain Res, vol. 1115, pp. 213-216, 2006.","Z. Farkas, I. Szirmai, and A. Kamondi, \"Impaired rhythm generation in \nessential tremor\", Mov Disord, vol. 21, pp. 1196-1199, 2006. \n[10] Heroux ME, Parisi SL, Larocerie-Salgado J, Norman KE. (2006) Upper \nextremity disability in essential tremor. Arch Phys Med Rehabil, 87, \n661-670, 2006. \n[11] F. J. Jimenez-Jimenez, L. Rubio, H. Alonso-Navarro, M. Calleja, B. \nPilo-de-la-Fuente, J. F. Plaza-Nieto, J. Benito-Leon, P. J.Garcia-Ruiz, and \nJ. A. Agundez, \"Impairment of rapid repetitive finger movements and \nvisual reaction time in patients with essential tremor. European Journal of \nNeurology, vol. 17, no. 1, pp. 152-159, 2010. \n[12] E. K. Tan, S. S. Lee, S. Fook-Chong , and S. Y. Lum, \"Evidence of \nincreased odds of essential tremor in Parkinson's disease\", Mov Disord, \nvol. 23, pp. 993-997, 2008. \n[13] E. D. Louis and S. J. Frucht, \"Prevalence of essential tremor in patients \nwith Parkinson's disease vs. Parkinson-plus syndromes\", Mov Disord, vol. \n22, pp. 1402-1407, 2007. \n[14] P. Hedera, J. Y. Fang, F. Phibbs, M. K. Cooper, P. D. Charles, and T. L. \nDavis, \"Positive family history of essential tremor influences the motor \nphenotype of Parkinson's disease\", Mov Disord, vol. 24, pp. 2285-2288, \n2009. \n[15] J. Benito-Leon and E. D. Louis, \"Essential tremor: emerging views of a \ncommon disorder\", Nat Clin Pract Neurol, vol. 2, pp. 666-678, 2006. \n[16] C. Duval, A. F. Sadikot, and M. Panisset, \"The detection of tremor during \nslow alternating movements performed by patients with early Parkinson's \ndisease\", Exp Brain Res, 154, pp. 395-398, 2004. \n[17] R. Nakamura, H. Nagasaki, and H. Narabayashi, \"Disturbances of rhythm \nformation in patients with Parkinson's disease. I. Characteristics of \ntapping response to the periodic signals\", Percept Mot Skills, vol. 46, pp. \n63-75, 1978. \n[18] G. E. Stelmach, and C. J. Worringham, \"The preparation and production \nof isometric force in Parkinson's disease\", Neuropsychologia, vol. 26, pp. \n93-104, 1988.\n[19] P. Viviani, and C. Terzuolo, \"Trajectory determines movement \ndynamics\", Neuroscience, vol. 7. pp. 431-437, 1982.\n[20] F. Lacquaniti, C. Terzuolo, and P. Viviani, \"The law relating the \nkinematic and figural aspects of drawing movements\", Acta Psychol, vol. \n54, pp. 115-130, 1983."]}

Functional electrical stimulation (FES) has been adopted to induce muscle contraction to provide functionally useful movements in spinal cord injured (SCI) individuals. It was described as electrical stimulation of muscle deprived of nervous control with a view of providing muscular contraction and providing a functionally useful movement. The term FES is applied to systems which attempt to restore lost or impaired neuromuscular function, such as standing and walking in cases of paraplegia. By the application of electrical pulses to neural pathways or, but less often, directly to muscles. It is also sometimes known as Functional Neuromuscular Stimulation or FNS. Figure 1 shows the demonstration of general applications of FES for the restoration of limb functions. Among all the limiting factors in the application of FES, muscle fatigue that can directly discontinue the application is considered the most important [1]. Many researchers have studied electrically elicited muscle fatigue of paralyzed limb muscles from the biomechanical, metabolic and electrophysiological aspects [2, 3, 4]. During electrical stimulation, the decline of torque values during isometric contraction is usually observed which exhibited a sigmoid-like curve consisting of a main slope and two plateaus [5, 6, 7]. Researchers reported that the first plateau represents the status before fatigue and the major slope indicates the exhausted expenditure of easily-fatigued (type II) MUs. Following the quick fatigue process, the final plateau represents the activation of the residual fatigue-resistant (type I) MUs [8]. From the electrophysiological aspect, the evoked EMG or compound muscle action potential (CMAP) of the stimulated muscle has been studied during the fatiguing process. The close correlation between muscle force and stimulus-evoked EMG peak to peak (PTP) amplitude indicates that the stimulus EMG amplitude could directly provide information for monitoring FES-induced muscle force and as control signals for compensating the decrease of muscle force due to fatigue [9, 10]. In addition to PTP, the other characteristics of CMAP, such as temporal features including latency, rise time to peak (RTP), and PTP duration (PTPd) as well as frequency characteristics have also been used to quantify the muscle fatigue process [11, 12]. Both temporal and frequency features were presumably related to

This study aimed to understand the myoelectric and mechanical characteristics of muscle recovering from electrically elicited fatigue. A modified Burke fatigue protocol was delivered to activate the tibialis anterior of 13 spinal cord injured subjects for 4 min. Before and after the fatigue protocol, a series of pulse trains was delivered to induce three twitches and a fused contraction at 0, 1, 3, and 5 min and then followed every 5 min for 60 min. The recovery processes of the ankle dorsiflexion torque and the evoked electromyography (EMG) parameters were analyzed and characterized by a first-order exponential equation. The recovery process was found to be faster in regard to tetanic muscle contraction. Factors relating to low-frequency fatigue, postfatigue potentiation, and the quickly normalized relaxation rate were taken into account for the discussion of this result. During the recovery process, the disassociation was found not only between twitch and tetanic contractions but also between mechanical and myoelectric activities. After the complete normalization of EMG parameters from about 15 min post fatigue, the tetanic force recovered incompletely to an asymptotic level.

The purpose of this study was to characterize handwriting deficits in children with developmental coordination disorder (DCD) using computerized movement analyses.Seventy-two children (40 females, 32 males; mean age 7 y, SD 7 mo; range 6 y 2 mo to 7 y 11 mo) with handwriting deficits (33 with DCD, 39 without DCD); and 22 age- and sex-matched children without handwriting deficits were asked to perform handwriting tasks on a digital tablet for the collection of kinematic and kinetic data. Practice times required to achieve automation of movement when writing an unfamiliar character were used to assess the motor learning of handwriting. The children were asked to copy three simple and three complex characters, and the velocity and axial pen force used for corresponding strokes were compared.The attainment of automated handwriting was markedly slower in children with handwriting deficits and DCD, who used a faster stroke velocity to write simple characters (1.22 times those without handwriting deficits), but when writing complex characters, their stroke velocity and pen force were lower (0.85 and 0.89 times those without handwriting deficits, respectively).By linking the results with neuromotor control theories, it was determined that children with DCD have difficulties performing the open-loop and closed-loop movements required for fluent handwriting.

The handwriting problems of elementary schoolchildren were investigated in this study. A questionnaire for evaluation of Chinese handwriting was developed and then administered to 165 children with handwriting deficits. Factor analysis indicated that the questionnaire has six major dimensions, including construction of characters, accuracy, developmental delay, pencil grip, gross movement, and emotional reaction. These six dimensions were utilized to search for subtypes of handwriting deficits. By further sampling, another 209 children were administered the handwriting evaluation questionnaire to classify their handwriting deficits. According to the severity of deficits on different dimensions of the questionnaire, K-means clustering was utilized to classify the children into four subtypes of mild, severe, motor-originated, and academic learning dysfunction subtypes. The classification by subtype might be helpful in planning interventions for children with handwriting deficits.

This study examines the design of a rational stimulation pattern for electrical stimulation and a robust closed-loop control scheme to improve cycling system efficacy for subjects with paraplegia. The stimulation patterns were designed by analyzing gravitation potential needed for the cycling movement of the lower limbs against a frictionless cycling ergometer and the response delay of electrically stimulated muscles. To simplify the cycling control system, the stimulation patterns were fixed and only the single gain of the stimulation patterns was adjusted via a feedback control algorithm. To circumvent the complexity involved with exactly modeling a stimulated muscle and cycling ergometer, a model-free fuzzy logic controller (FLC) was adopted herein for the authors' control scheme. Comparison between FLC and conventional proportional-derivative (PD) controllers demonstrated that the PLC with asymmetrical membership function enabled the subject with paraplegia to maintain varied desired cycling speeds, particularly at lower cycling speed. By incorporating the rational stimulation patterns, the FLC can produce a smooth and prolonged cycling movement deemed necessary for designing various training protocols.

The muscle fatigue characteristics was studied from biomechanical modelling analysis and stimulus EMG measurement during FES-induced cycling movement. The inverse dynamics method was used to calculate the knee joint torque which represents the muscle force generated during cycling movement. The peak-to-peak of stimulus EMG, after suppression of stimulus artifact, was adopted as a fatigue indicator during dynamic movement. Our observations from stimulus EMG and inverse dynamics indicate that the paralyzed muscles might not reach complete fatigue when the cycling movement cannot continue.