Predictors of quantitative and qualitative Halstead finger-tapping scores in low socioeconomic status school-age children.

Two hundred and thirteen low socioeconomic school-age children in grades 1 through 8 were administered the Halstead Finger Oscillation (or Tapping) Test (HFTT). All children were age appropriate for their grade in school and were not requiring special education services. Hierarchical multiple regression analysis revealed that a composite age/grade classification score, gender, and estimated level of intelligence accounted for approximately 40% of the variability in dominant and nondominant hand scores for these children (multiple R = .627, R(2) = +.393 for the dominant and multiple R = +.607, R(2) = +.368 for the nondominant hand). Only the age/grade level of the child (R(2) = .168) predicted the ability to inhibit adjacent finger movements when performing the HFTT task. Regional normative data for low socioeconomic school-age children are presented. Neurodevelopmental changes in the cortical and subcortical systems underlying finger movement may account for some of the variability observed in children when performing the HFTT.     

Asymmetric control of force and symmetric control of timing in bimanual finger tapping

An experiment was conducted to examine the control of force and timing in bimanual finger tapping. Participants were trained to produce both unimanual (left or right hand) and bimanual finger-tapping sequences with a peak force of 200 g and an intertap interval (ITI) of 400 ms. During practice, visual force feedback was provided pertaining to the hand performing the unimanual tapping sequences and to either the dominant or the nondominant hand in the bimanual tapping sequences. After practice, the participants produced the learned unimanual and bimanual tapping sequences in the absence of feedback. In those trials the force produced by the dominant (right) hand was significantly larger than that produced by the nondominant (left) hand, in the absence of a significant difference between the ITIs produced by both hands. Furthermore, after unilateral feedback had been provided of the force produced by the nondominant hand, the force output of the dominant hand was significantly more variable than that of the nondominant hand. In contrast, after feedback had been provided of the force produced by the dominant hand, the variability of the force outputs of the two hands did not differ significantly. These results were discussed in the light of both neurophysiological and anatomical findings, and were interpreted to imply that the control of timing (in bimanual tasks) may be more tightly coupled in the motor system than the control of force.     

Effects of an Occupational Therapy Hand Dominance Transfer Intervention for Soldiers With Crossed Hand-Eye Dominance

Crossed dominance (CD) is defined as an individual's dominant hand and dominant eye being on opposite sides of the body. CD negatively impacts an individual's ability to accurately aim and fire long-barreled guns. The authors developed and evaluated a hand dominance transfer (HDT) intervention to improve the M16 rifle shooting accuracy, efficiency, and skill transfer. Twenty-four U.S. Army soldiers with CD were taught how to handle and fire an M16 rifle using the nondominant hand. Training was conducted at a military, indoor laser-equipped weapons simulator. Accuracy for shooting 40 rounds at baseline with the nondominant eye and dominant hand (NDE/DH) was 22.12 compared to shooting 30.46 with the dominant eye and nondominant hand (DE/NDH). This difference was statistically significant with p = .000. The transfer of shooting accuracy skill (retention) following the HDT intervention was 33.42 with a comparative p value of .100. Efficiency of shooting 10 rounds at baseline with the NDE/DH was 6.3 compared to shooting 7.3 with the DE/NDH. This difference was not statistically significant (p = .107). The transfer of shooting efficiency skill (retention) was 7.96 with a comparative p value of .349. This study supports shooting with the DE/NDH. HDT could be further developed to address the soldiering skill of shooting an M16.     

The interaction of respiration and visual feedback on the control of force and neural activation of the agonist muscle

The purpose of this study was to compare force variability and the neural activation of the agonist muscle during constant isometric contractions at different force levels when the amplitude of respiration and visual feedback were varied. Twenty young adults (20–32 years, 10 men and 10 women) were instructed to accurately match a target force at 15% and 50% of their maximal voluntary contraction (MVC) with abduction of the index finger while controlling their respiration at different amplitudes (85%, 100% and 125% normal) in the presence and absence of visual feedback. Each trial lasted 22 s and visual feedback was removed from 8–12 and 16–20 s. Each subject performed three trials with each respiratory condition at each force level. Force variability was quantified as the standard deviation of the detrended force data. The neural activation of the first dorsal interosseus (FDI) was measured with bipolar surface electrodes placed distal to the innervation zone. Relative to normal respiration, force variability increased significantly only during high-amplitude respiration (∼63%). The increase in force variability from normal- to high-amplitude respiration was strongly associated with amplified force oscillations from 0 to 3 Hz (R² ranged from .68 to .84, p < .001). Furthermore, the increase in force variability was exacerbated in the presence of visual feedback at 50% MVC (vision vs. no-vision: .97 vs. .87 N) and was strongly associated with amplified force oscillations from 0 to 1 Hz (R² = .82) and weakly associated with greater power from 12 to 30 Hz (R² = .24) in the EMG of the agonist muscle. Our findings demonstrate that high-amplitude respiration and visual feedback of force interact and amplify force variability in young adults during moderate levels of effort.     

Difference in Cortical Relay Time Between Intrinsic Muscles of Dominant and Nondominant Hands

The authors aimed to calculate and compare cortical relay time (CRT) between intrinsic hand muscles and between homonymous muscles of dominant and nondominant hands. The participants comprised 22 healthy volunteers. The CRT for long-latency reflexes (LLRs) was calculated by subtracting the peak latency of somatosensory evoked potentials of component N20 and the onset latency of motor evoked potentials from the onset latency of LLRs. CRT was significantly shorter for the first dorsal interosseous muscle than for the abductor pollicis brevis muscle, regardless of hand dominance. CRT for the abductor pollicis brevis muscle was significantly shorter in the dominant hand than in the nondominant hand. Evaluation of CRT for intrinsic muscles might be beneficial in the understanding of individuated finger functions.     

Control of oscillatory force tasks: Low-frequency oscillations in force and muscle activity

Force variability during steady force tasks is strongly related to low-frequency oscillations (<0.25 Hz) in force. However, it is unknown whether low-frequency oscillations also contribute to the variability of oscillatory force tasks. To address this, twelve healthy young participants (21.08 ± 2.99 years, 6 females) performed a sinusoidal force task at 15% MVC at two different frequencies (0.5 and 1 Hz) with isometric abduction of the index finger. We recorded the force from the index finger and surface EMG from the first dorsal interosseous muscle and quantified the following outcomes: 1) trajectory variability and accuracy; 2) power spectrum of force and EMG bursting below 2 Hz; 3) power spectrum of the interference EMG from 4 to 60 Hz. The trajectory variability and error significantly increased from 0.5 to 1 Hz task (P < 0.01). Increased force oscillations <0.25 Hz contributed to greater trajectory variability and error for both the 0.5 and 1 Hz oscillatory task (R² > 0.33; P < 0.05). The <0.25 Hz oscillations in force were positively associated with greater power in the <0.25 Hz for EMG bursting (R² > 0.52; P < 0.01). The modulation of the interference EMG from 35 to 60 Hz was a good predictor of the <0.25 Hz force oscillations for both the 0.5 Hz task and 1 Hz task (R² > 0.66; P < 0.01). These results provide novel evidence that, similar to steady contractions, low-frequency oscillations of the motor neuron pool appear to be a significant mechanism that controls force during oscillatory force tasks.     

Contralateral Transfer of the Phenomenon of Repeated Bout Rate Enhancement in Unilateral Index Finger Tapping

Abstract

These hypotheses were tested: (1) Freely chosen frequency in unilateral index finger tapping is correlated between the two index fingers, and (2) A 3-min bout of unilateral index finger tapping followed by 10?min rest results in an increase of the freely chosen tapping frequency performed by the contralateral index finger in a second bout. Thirty-two adults participated. Freely chosen tapping frequencies from first bouts were 167.2?±?79.0 and 161.5?±?69.4 taps/min for the dominant and non-dominant hand, respectively (p=.434). These variables correlated (R=.86, p<.001). When bout one and two were performed with the dominant and non-dominant hand, respectively, the frequency increased by 8.1%±17.2% in bout two (p=.011). In opposite order, the frequency increased by 14.1%±17.5% (p<.001), which was not different from the ～8% (p=.157).     

Relationships among age, sex, and lateral dominance for 3- to 6-year-old children performing unilateral stance

To assess influence of age, sex, and lateral dominance on children's unilateral stance, from 6 Houston area preschools and day-care centers, 121 subjects were randomly selected and judged by teachers as normal 3- to 6-yr-old children. The children were tested for eye, hand, and foot preference and were then classified on over-all dominance. Maximal duration of unilateral stance, or up to 60 sec., was tested on each foot. Means over age groups show progressive increase in duration of unilateral stance with increasing age. No sex differences were found. A stepwise multiple correlation-regression showed stance on the nondominant foot and age as the only significant variables in stance on the dominant foot. Clinically, this study can help in evaluating children for neurodevelopmental disorders.     

Finger gnosia: a predictor of numerical abilities in children?

This paper aimed to test the specificity of predicting power of finger gnosia on later numerical abilities in school-age children and to contribute to the understanding of this effect. Forty-one children were tested in the beginning of Grade 1 on finger gnosia, left–right orientation (another sign of the Gerstmann “syndrome”), and global development. Fifteen months later, numerical and reading abilities were assessed. Analyses of the results indicated that, contrary to the general measures of cognitive development, performance in the finger gnosia test was a good predictor of numerical skills 1 year later but not of reading skills, which proves the specificity of that predictor. The same conclusion was also true for the left–right orientation. However, finger gnosia could equally predict performance in numerical tasks that do or do not rely heavily on finger representation or on magnitude representation. Results are discussed in terms of the localizationist and the functional hypotheses.     

Friendship Quality and School Achievement: A Longitudinal Analysis During Primary School

This study examined the longitudinal relationship between friendship quality (positive and negative) and school achievement among 228 school-age children (51% girls, M = 8.09, SD = 0.41). A three-wave cross-lagged analysis was used to determine the direction of influence between these domains across school years. Findings revealed that: (a) school achievement in second grade decreased negative friendship quality in third grade; (b) school achievement in second grade predicted positive friendship quality in third grade; (c) positive friendship quality in third grade predicted school achievement in fourth grade. The protective role of school achievement against peer relationship impairment and the reciprocal relationship between positive friendship quality and school achievement were underlined. Implications for educational practices for Italian primary schools are discussed.     

Ezekiel’s classic estimator of the population squared multiple correlation coefficient: Monte Carlo-based extensions and refinements

Abstract

Ezekiel’s adjusted R² is widely used in linear regression analysis. The present study examined the statistical properties of Ezekiel’s measure through a series of Monte Carlo simulations. Specifically, we examined the bias and root mean squared error (RMSE) of Ezekiel’s adjusted R² relative to (a) the sample R² statistic, and (b) the sample R² minus the expected value of R². Simulation design factors consisted of sample sizes (N?=?50, 100, 200, 400), number of predictors (2, 3, 4, 5, 6), and population squared multiple correlations (ρ² = 0, .10, .25, .40, .60). Factorially crossing these design factors resulted in 100 simulation conditions. All populations were normal/Gaussian, and for each condition, we drew 10,000 Monte Carlo samples. Regarding systematic variation (bias), results indicated that with few exceptions, Ezekiel’s adjusted R² demonstrated the lowest bias. Regarding unsystematic variation (RMSE), the performance of Ezekiel’s measure was comparable to the other statistics, suggesting that the bias-variance tradeoff is minimal for Ezekiel’s adjusted R². Additional findings indicated that sample size-to-predictor ratios of 66.67 and greater were associated with low bias and that ratios of this magnitude were accompanied by large sample sizes (N?=?200 and 400), thus suggesting that researchers using Ezekiel’s adjusted R² should aim for sample sizes of 200 or greater in order to minimize bias when estimating the population squared multiple correlation coefficient. Overall, these findings indicate that Ezekiel’s adjusted R² has desirable properties and, in addition, these findings bring needed clarity to the statistical literature on Ezekiel’s classic estimator.     

Effects of speaking upon the rate and variability of concurrent finger tapping in children

Tapping rate and variability were measured as 73 normal, right-handed children in Grades 1–4 engaged in speeded unimanual finger tapping with and without concurrent recitation. Speaking reduced the rate of tapping and increased its variability to a greater extent in younger children than in older children. Developmental changes in variability but not rate were attributable to a greater number of lengthy (>500 ms) pauses in the tapping of younger children. Speaking slowed the right hand more than the left, and the degree of this asymmetry was constant across grade levels. The right-hand effect for tapping rate was not attributable to lengthy pauses. In contrast, asymmetric increases in tapping variability occurred only among children in Grade 1 and only when lengthy pauses were included in the data. The results implicate three mechanisms of intertask interference: one involving capacity limitations, a second involving cross-talk between motor control mechanisms for speech and finger movement, respectively, and a third factor involving occasional diversion of attention from tapping to speaking. These mechanisms are discussed in relation to developmental changes in mental capacity.     

Rapid automatized naming (RAN) in children with ADHD: An ex-Gaussian analysis

Children with ADHD demonstrate increased frequent “lapses” in performance on tasks in which the stimulus presentation rate is externally controlled, leading to increased variability in response times. It is less clear whether these lapses are also evident during performance on self-paced tasks, e.g., rapid automatized naming (RAN), or whether RAN inter-item pause time variability uniquely predicts reading performance. A total of 80 children aged 9 to 14 years—45 children with attention-deficit/hyperactivity disorder (ADHD) and 35 typically developing (TD) children—completed RAN and reading fluency measures. RAN responses were digitally recorded for analyses. Inter-stimulus pause time distributions (excluding between-row pauses) were analyzed using traditional (mean, standard deviation [SD], coefficient of variation [CV]) and ex-Gaussian (mu, sigma, tau) methods. Children with ADHD were found to be significantly slower than TD children (p < .05) on RAN letter naming mean response time as well as on oral and silent reading fluency. RAN response time distributions were also significantly more variable (SD, tau) in children with ADHD. Hierarchical regression revealed that the exponential component (tau) of the letter-naming response time distribution uniquely predicted reading fluency in children with ADHD (p < .001, ΔR² = .16), even after controlling for IQ, basic reading, ADHD symptom severity and age. The findings suggest that children with ADHD (without word-level reading difficulties) manifest slowed performance on tasks of reading fluency; however, this “slowing” may be due in part to lapses from ongoing performance that can be assessed directly using ex-Gaussian methods that capture excessively long response times.     

Production of successive force impulses by the left and right hands

Right-handed participants made ballistic force impulses with the index finger of their left or right hand to match the amplitude of 2 successive visual targets whose onset was separated by 600-850 ms. The targets specified either low- (10% of maximum voluntary contraction; MVC) or high- (25% MVC) force level and were presented in all combinations (low-low, low-high, high-low, high-high). The amplitude of the 1st force impulse affected that of the 2nd, forming an effect that was greatest at the shortest interresponse intervals and that decayed with increasing intervals. This effect was smaller with a shorter time course in the dominant hand than the nondominant hand, suggesting a greater ability of the dominant hand to make successive independent responses.     

Optional shift behavior as a function of age and dimensional dominance

An optional reversal-nonreversal shift task for which the relevant color or form cues were either dominant or nondominant was presented to 320 Ss, 6 through 20 years of age. Dominance, as defined in terms of relative cue similarity, was related to initial learning and shift behavior for kindergarten and third-grade Ss; but not for sixth-grade and college Ss. The speed of initial learning and percentage of reversal shifts was related to age when the nondominant dimension was relevant. There were no developmental differences when the dominant dimension was relevant.     

Characteristics of finger force production during one- and two-hand tasks

Relations among finger forces were studied during one-hand and two-hand isometric maximal force production tasks in right- and left-handers. We particularly focused on the phenomena of force deficit during one-hand multi-finger tasks and of bilateral force deficit during two-hand tasks. Ten healthy subjects (five of them left-handed) performed maximal voluntary force production tasks with different finger combinations involving fingers of one of the hands or of both hands together. In one-hand tasks, finger enslaving (forces produced by fingers that were not instructed to produce force) was larger in the dominant hand, while force deficit (drop in individual finger peak force during multi-finger tasks) showed no differences between the hands. An additional drop in finger forces was seen in two-hand tests (bilateral deficit). The magnitude of the bilateral deficit for a hand was larger for tasks involving fewer fingers within the hand and more fingers in the other hand, with a ceiling effect. Smaller bilateral deficit was seen in tasks involving symmetrical finger combinations. In two-hand tasks that could potentially lead to the generation of large total moments in the frontal plane, the hand that was expected to generate larger moments showed larger bilateral deficit, so that the magnitude of the total moment was reduced. These observations suggest that force deficit within a hand and bilateral deficit have different origins but their effects are combined at a certain level of the multi-finger control hierarchy. Bilateral deficit may display task dependence reflecting, in particular, the principle of minimization of secondary moments. A double-representation, mirror-image hypothesis is suggested to provide a neurophysiological basis for the observed patterns of bilateral deficit.     

Lateralized brain injury and behavior problems in children

This study investigated the types of behavior problems found in children with lateralized brain lesions. Children referred for neuropsychological assessment were assigned to dominant (DH) or nondominant (NDH) groups on the basis of history of neurological disease or injury, findings on neurological examination, functional and structural laboratory findings, and neuropsychological assessment. Over two-thirds fell into the clinical range of behavior problems by parental report on the Achenbach Child Behavior Checklist. Degrees of pathology were nearly equal. DH children showed more externalizing than internalizing symptomatology. NDH children showed more internalizing than externalizing behavior problems. Results are discussed in terms of symptom formation based on lateralization of lesion.     

A translational application of music for preschool cognitive development: RCT evidence for improved executive function,self-regulation,and school readiness

The benefits of active music participation and training for cognitive development have been evidenced in multiple studies, with this link leveraged in music therapy approaches with clinical populations. Although music, rhythm, and movement activities are widely integrated into children's play and early education, few studies have systematically translated music therapy-based approaches to a nonclinical population to support early cognitive development. This study reports the follow-up effects of the Rhythm and Movement for Self Regulation (RAMSR) program delivered by generalist preschool teachers in low socioeconomic communities. This randomized control trial (RCT) involved 213 children across eight preschools in disadvantaged communities in Queensland, Australia. The intervention group received 16–20 sessions of RAMSR over 8 weeks, while the control group undertook usual preschool programs. Primary outcome measures included executive function (child assessment of shifting, working memory, and inhibition) and self-regulation (teacher report), with secondary outcomes of school readiness and visual-motor integration. Data were collected pre- and post-intervention, and again 6 months later once children had transitioned into school. Results demonstrated significant intervention effects across the three time points for school readiness (p = 0.038, η_p² = 0.09), self-regulation (p < 0.001, η_p² = 0.08), and inhibition (p = 0.002 η_p² = 0.23). Additionally, the feasibility of building capacity in teachers without any music background to successfully deliver the program was evidenced. These findings are important given that children from low socioeconomic backgrounds are more likely to need support for cognitive development yet have inequitable access to quality music and movement programs.

Research Highlights

• Initial effects of self-regulation from a rhythm and movement program were sustained following transition into school for children from disadvantaged backgrounds.
• Delayed effects of inhibition and school readiness from a rhythm and movement program appeared 6 months post-intervention as children entered school.
• Generalist teachers can successfully implement a rhythm and movement program, which boosts critical developmental cognitive skills.

     

What children know about the source of their knowledge without reporting it as the source

We tested the development of attentional functions within Syrian and German children of pre-school and school age (n = 562, 5–12 years), using the Test of Attentional Performance for Children (KITAP). After controlling the intelligence (IQ) and socioeconomic status (SES), age-related improvements were found in all the attentional functions, with rapid improvements between 8 and 10 years. Gender differences were also found in some attention performances. More importantly, cultural differences were also evident. The performance in the activation functions “Alertness” and “Vigilance” were independent from cultural background, whereas performances in Sustained Attention, in functions of visuospatial orienting (Visual Scanning) and executive systems (Divided Attention, Flexibility and Distractibility) revealed cultural differences. In general, the Syrian children showed slower performances, higher variability of responses and more errors compared with German children. The overall results of the study supports the universal development of attention functions during school age, and show that attention performances could be influenced by characteristics of the cultural background (Arabic-Syrian: collectivistic–dependent; and Western German: individualistic–independent).     

An examination of practice and laterality effects on the Purdue Pegboard and Moving Beans with Tweezers

The purpose of this study was to examine the relation of practice or learning and laterality on the Purdue Pegboard and the Moving Beans with Tweezers test. The subjects were 30 right-handed, healthy young male adults (age: M = 21.1, SD = 1.9 yr.). The subjects performed both tests five times with each hand. A two-way analysis of variance (hand x trial) for scores on the Purdue Pegboard showed that Trial 1 had a significantly lower mean than Trials 4 and 5 with the dominant hand, and scores on Trials 1 and 3 were lower than that on Trial 5 for the nondominant hand. For the Moving Beans with Tweezers test, Trial 1 had a significantly lower score than Trial 5 with the nondominant hand. The dominant hand produced significantly higher values on all trials of both tests. Intraclass correlation coefficients of Trials 2 and 3 were high, and means were significantly higher for the dominant hand. A correlation between other tests was not high (r = .37-.46) for both hands. All correlations among five trials on both tests were significant and high (Purdue Pegboard-Dominant: average r =.72, [r] = .60-.80, Purdue Pegboard-Nondominant: average r = .59, [r] = .43-.76), (Moving Beans-Dominant: average r = .74, [r] = .57-.81, Moving Beans-Nondominant: average r =.71, [r] = .55-.87). Correlations among five trials for the ratio of dominant:nondominant hand on both tests were significant and moderate (Moving Beans: average r = .28, [r] = .08-.57, Purdue Pegboard: average r = .41, [r] = .19.56). Performance with the dominant hand is superior to that of the nondominant hand on both tests. Practice effects are found for both tests across five trials. The Moving Beans with Tweezers test also showed laterality of practice effects. The two tests may measure different abilities.