Assessing motor competence in kicking in individuals with Down syndrome through wearable motion sensors.

BACKGROUND: Kicking a ball is a very frequent action in sport and leisure time activities and a low proficiency in this skill could limit the participation in recreational sport activities. This issue is emphasised in individuals with Down syndrome (IDS) for which data about motor competence in kicking are limited to children. Here, we aim at evaluating the kicking competence of IDS combining a qualitative and a quantitative method. METHODS: Twenty-three adult IDS and 21 typically developed individuals (ITD) volunteered to participate in the study. Peak-to-peak 3D linear acceleration and angular velocity were recorded at 200 samples/s using two inertial measurement units placed on the lower back and lateral malleolus of the dominant limb during kicking. Motor competence in kicking was assessed according to the criteria proposed in the test of gross motor development version 3 (TGMD-3). RESULTS: Individuals with Down syndrome showed lower motor competence (ITD: 5.9 ± 1.2; IDS: 3.2 ± 2.0) and lower angular velocities about the cranio-caudal (ITD: 3.0 ± 1.8; IDS: 2.1 ± 1.1 rad/s) and medio-lateral axes (ITD: 4.5 ± 1.5; IDS: 3.0 ± 1.1 rad/s) of the trunk compared with ITD. Shank angular velocity about the medio-lateral axis was lower in IDS (ITD: 14.3.6 ± 4.0; IDS: 9.9 ± 2.8 rad/s). CONCLUSIONS: The lower trunk angular velocity in IDS may limit the possibility to rely on the proximal-to-distal sequencing commonly observed in kicking and generate high shank angular velocity upon ball impact. The lower trunk angular velocity may result from orthopaedic features of the pelvic girdle and possibly from a poorer neuromuscular control of core muscles.

Effect of task complexity on motor and cognitive preparatory brain activities.

In the present study, we investigated scalp-recorded activities of motor and cognitive preparation preceding stimulus presentation in relatively simple and complex visual motor discriminative response tasks (DRTs). Targets and non-targets were presented (with equal probability) in both tasks, and the complexity of the task depended on the discrimination and categorization processing load, which was based on the number of stimuli used (two stimuli in the simple- and four in the complex-DRT, respectively). We recorded event-related potentials (ERPs) in 16 participants in simple-DRT and 16 participants in complex-DRT. At the behavioral level, the performance was faster and more accurate in simple-DRT. Two pre-stimulus ERPs were considered: the central Bereitschaftspotential (BP) and the prefrontal negativity (pN). Both components showed earlier onset and larger amplitude in the complex-DRT. Overall, the simple-DRT required less motor and cognitive preparation in premotor and prefrontal areas compared to the complex-DRT. Present findings also suggest that the pN component was not reported in previous studies, likely because most ERP literature focusing on pre-stimulus ERP used simple-DRTs, and with such a task the pN amplitude is small and can easily go undetected.

Females are more proactive, males are more reactive: neural basis of the gender-related speed/accuracy trade-off in visuo-motor tasks.

In the present study, we investigated neural correlates associated with gender differences in a simple response task (SRT) and in a discriminative response task (DRT) by means of event-related potential (ERP) technique. 120 adults participated in the study, and, based on their sex, were divided into two groups matched for age and education level. Behavioral performance was assessed with computing response speed, accuracy rates and response consistency. Pre- and post-stimulus ERPs were analyzed and compared between groups. Results indicated that males were faster than females in all tasks, while females were more accurate and consistent than males in the more complex tasks. This different behavioral performance was associated with distinctive ERP features. In the preparation phase, males showed smaller prefrontal negativity (pN) and visual negativity (vN), interpreted as reduced cognitive preparation to stimulus occurrence and reduced reliance on sensory proactive readiness, respectively. In the post-stimulus phase, gender differences were present over occipital (P1, N1, P2 components) and prefrontal (pN1, pP1, pP2 components) areas, suggesting allocation of attentional resources at distinct stages of information processing in the two groups. Overall, the present data provide evidence in favor of a more proactive and cautious cognitive processing in females and a more reactive and fast cognitive processing in males. In addition, we confirm that (1) gender is an important variable to be considered in ERP studies on perceptual processing and decision making, and (2) the pre-stimulus component analysis can provide useful information concerning neural correlates of upcoming performance.

Modality-specific sensory readiness for upcoming events revealed by slow cortical potentials.

Human brain activity allows to anticipate future events and to prepare the next action accordingly; consistently, event-related potential (ERP) studies found action preparatory brain activities in the premotor and prefrontal cortex. In the present study, we investigated the preparatory activity in the sensory cortical regions. Slow cortical potentials were recorded during passive tasks, i.e., subjects expected for a sensory stimulus and no motor or cognitive response were required. In particular, we tested the hypothesis that perceptual anticipatory cortical mechanisms were modality specific. Three groups of 21 young adults underwent passive perceptual tasks in different sensory modalities (visual, auditory, or somatosensory). We confirmed the presence of a visual negativity (vN) component for the visual modality starting about 800 ms before stimulus with source in extrastriate areas and we found novel modality-specific sensory readiness components for the auditory and somatosensory modalities. The auditory positivity (aP) started about 800 ms before stimulus with source in bilateral auditory cortices and the somatosensory negativity (sN) started about 500 ms before stimulus with source in the somatosensory secondary cortex, contralateral to the stimulated hand. The scalp topography and intracranial sources of these three slow preparatory activities were mirrored with inverted polarity at early post-stimulus stage evoking the well-known visual P1, auditory N1, and somatosensory P100 components. Present findings contribute to widening the family of slow wave preparatory components, providing evidence about the relationship between top-down and bottom-up processing in sensory perception.

Weak proactive cognitive/motor brain control accounts for poor children's behavioral performance in speeded discrimination tasks.

BACKGROUND: Motor and inhibitory control rely on frontal cortex activity, which is known to reach full maturation only in late adolescence. The development of inhibitory control has been studied using event-related potentials (ERP), focusing on reactive processing (i.e. the N2 and the P3 components). Scarce information exists concerning pre-stimulus activity as that represented by the Bereinshafstpotential (BP) and by the prefrontal negativity (pN). Further, no literature exists concerning the post-stimulus components originating within the anterior insula (pN1, pP1, pP2). This study aims at associating children performance with these motor-cognitive processing in frontal brain areas. METHODS: High-resolution EEG recordings were employed to measure ERPs from 18 children (12 years old) and 18 adults (28 years old) during a visuo-motor discriminative response task. Response time (RT), commission (CE) and omission errors, and RT variability were compared between groups. At brain level, two pre-stimulus (BP and pN) and seven post-stimulus (P1; pN1; N1; pP1; N2; pP2; P3) ERP components were compared between groups. RESULTS: Children showed slower and more variable RTs and poorer inhibition (higher CEs) than adults. At electrophysiological level, children presented smaller BP and pN. After stimulus onset, children showed lower amplitude of N1, pP1, P3, and pP2 components. The P1, pP1, N2 and P3 were delayed compared to adults. CONCLUSIONS: Our results demonstrate that children are characterized by less intense task-related proactive activities in frontal cortex, which may account for subsequent poor and delayed reactive processing and, thus, for inaccurate and slow performance.

Exercise-related cognitive effects on sensory-motor control in athletes and drummers compared to non-athletes and other musicians.

Both playing a musical instrument and playing sport produce brain adaptations that might affect sensory-motor functions. While the benefits of sport practice have traditionally been attributed to aerobic fitness, it is still unknown whether playing an instrument might induce similar brain adaptations, or if a specific musical instrument like drums might be associated to specific benefits because of its high energy expenditure. Since the aerobic costs of playing drums was estimated to be comparable to those of average sport activities, we hypothesized that these two groups might show both behavioral and neurocognitive similarities. To test this hypothesis, we recruited 48 young adults and divided them into four age-matched groups: 12 drummers, 12 athletes, 12 no-drummer musicians and 12 non-athletes. Participants performed a visuo-motor discriminative response task, namely the Go/No-go, and their cortical activity was recorded by means of a 64-channel electroencephalography (EEG). Behavioral performance showed that athletes and drummers were faster than the other groups. Electrophysiological results showed that the pre-stimulus motor preparation (i.e. the Bereitschaftspotential or BP) and attentional control (i.e., the prefrontal negativity or pN), and specific post-stimulus components like the P3 and the pP2 (reflecting the stimulus categorization process) were enhanced in the athletes and drummers' groups. Overall, these results suggest that playing sport and drums led to similar benefits at behavioral and cognitive level as detectable in a cognitive task. Explanations of these findings, such as on the difference between drummers and other musicians, are provided in terms of long-term neural adaptation mechanisms and increased visuo-spatial abilities.

Cardio-respiratory and electromyographic responses to ergometer and on-water rowing in elite rowers.

The aim of this study was to compare muscle activation and cardio-respiratory response during ergometer and on-water rowing. Nine internationally competitive rowers (five Olympic Games medal winners, age 25.6 ± 4.8 years) were requested to perform a 1,000 m race simulation test in the two conditions. Surface electromyographic (sEMG) signals from trapezius superior (TRS), latissimus dorsi (LD), biceps brachii (BB), rectus femoris (RF), vastus medialis (VAM), vastus lateralis (VAL), biceps femoris (BF) and tibialis anterior (TA) muscles were recorded continuously during the tests together with other cardio-respiratory parameters: heart rate (HR), ventilation (VE), oxygen consumption (VO2). On-water, subjects covered the same distance in a longer time (218.4 ± 3.8 s vs. 178.1 ± 5.6 s during ergometer test). TRS, LD, BB, RF, VAM and VAL muscle activation on-water was lower than off-water during the rowing race. VO2 and VE responses were similar between the two conditions even if the time to complete the 1,000 m race simulation test was higher on-water. The results indicate that for most of the analyzed muscles EMG activation on the ergometer is higher than on-water with the maximal activity at the beginning of the on-water test due reasonably to overcome the forces opposing the forward motion, while the ergometer task elicited increasing muscle activation over time. The present data may be considered by coaches when choosing a rowing ergometer in substitution for the training on-water or when relying on the indoor tests to select the crew.