Efficacy of Sensory Interventions on School Participation of Children With Sensory Disorders: A Systematic Review.

Research demonstrates lower school participation in children with sensory disorders. However, the scientific body of evidence supporting existing sensory intervention modalities is difficult to tackle. More specifically, the literature appears poorly organized, with a highly variable terminology, often with nonoverlapping definitions and lack of good keywords classification that would help organize the diversity of approaches. This systematic review organizes the body of evidence for 3 specific approaches (sensory based, sensorimotor, and sensory integration) and questions their efficacy in improving school participation for children with sensory disorders. Two methods were compared: first, a standard systematic review of the literature in 3 databases using appropriate keywords and descriptors, then an original method based on forward and backward citation connections. A total of 28 studies were retrieved, of which only 7 used the standard method for systematic reviews. For sensory-based approaches, the efficacy of weighted-vest varies according to different factors such as the protocol of use. For sensorimotor approaches, the efficacy of therapy balls, air cushions, platform swing, and physical exercise varies according to the child's sensory characteristics. The efficacy of the sensory integration approach remains mixed across studies.

Children's Emotional Self-Regulation in the Context of Adversity and the Association with Academic Functioning.

The aims of this study were to study reciprocal interactions between emotion regulation skills, association of these skills with children's school functioning and how these underlying skills develop in children in the context of adversity. 48 children (mean age = 5 years 8.2 months) were divided into an adversity risk group and a low-risk group. Emotional regulation was assessed via an emotion identification task, a Stroop task and near-infrared spectroscopy. School functioning was documented using the Social Skills Improvement System with parents and teachers. During the Stroop task, there was a difference in the activation of the right Brodmann area 8 in both groups. During the emotion regulation tasks, BA8L and BA9R showed activation and an association with school functioning. These results contribute to the accuracy of cerebral mapping associated with emotion regulation and support its potential contribution in preventive programs aimed at the functioning of children at risk of school difficulties.

Effect of pain on deafferentation-induced modulation of somatosensory evoked potentials.

There is a large body of evidence showing substantial sensorimotor reorganizations after an amputation. These reorganizations are believed to contribute to the development of phantom limb pain, but alternatively, pain might influence the plasticity triggered by the deafferentation. The aim of this study was to test whether pain impacts on deafferentation-induced plasticity in the somatosensory pathways. Fifteen healthy subjects participated in 2 experimental sessions (Pain, No Pain) in which somatosensory evoked potentials (SSEPs) associated with electrical stimulation of the ulnar nerve were assessed before and after temporary ischemic deafferentation induced by inflation of a cuff around the wrist. In the Pain session capsaicin cream was applied on the dorsum of the hand 30 minutes prior to cuff inflation. Results show that pain decreased the amplitude of the N20 (main effect of condition, p = 0.033), with a similar trend for the P25. Temporary ischemic deafferentation had a significant effect on SSEPs (main effect of time), with an increase in the P25 (p = 0.013) and the P45 amplitude (p = 0.005), together with a reduction of the P90 amplitude (p = 0.002). Finally, a significant time x condition interaction, reflecting state-dependent plasticity, was found for the P90 only, the presence of pain decreasing the reduction of amplitude observed in response to deafferentation. In conclusion, these results show that nociceptive input can influence the plasticity induced by a deafferentation, which could be a contributing factor in the cortical somatosensory reorganization observed in chronic pain populations.

At-home and in-group delivery of constraint-induced movement therapy in children with hemiparesis: A systematic review.

BACKGROUND: Constraint-induced movement therapy (CIMT) is increasingly recognized as an effective therapy for children with hemiparesis. However, the effectiveness of CIMT outside the standard rehabilitation protocol in clinical settings is less known. The aim of this systematic review was to investigate the effectiveness of CIMT conducted at home or in a group. METHODS: We searched CINAHL, PubMed and ScienceDirect in August 2017 to select articles of studies investigating the impact of CIMT performed at home and in a group on affected upper-limb ability, occupational performance, and quality of life of children. Quality was evaluated with the PEDro scale. RESULTS: Among 374 reports of studies, 30 met the criteria; 15 examined CIMT at home and 15 in a group. CIMT with the 2 delivery models, at home or in a group, had a positive effect on the affected upper-limb ability and occupational performance. The quality of evidence was high for both these outcomes. However, the evidence was weaker and the results too limited to conclude on the impact on quality of life. The data also suggested that the glove may not be the best type of constraint. CONCLUSIONS: CIMT performed at home or in a group may be a promising intervention for rehabilitation for children with hemiparesis, but more studies on the impact on quality of life are warranted.

Transcranial direct current stimulation over multiple days enhances motor performance of a grip task.

BACKGROUND: Recovery of handgrip is critical after stroke since it is positively related to upper limb function. To boost motor recovery, transcranial direct current stimulation (tDCS) is a promising, non-invasive brain stimulation technique for the rehabilitation of persons with stroke. When applied over the primary motor cortex (M1), tDCS has been shown to modulate neural processes involved in motor learning. However, no studies have looked at the impact of tDCS on the learning of a grip task in both stroke and healthy individuals. OBJECTIVE: To assess the use of tDCS over multiple days to promote motor learning of a grip task using a learning paradigm involving a speed-accuracy tradeoff in healthy individuals. METHODS: In a double-blinded experiment, 30 right-handed subjects (mean age: 22.1±3.3 years) participated in the study and were randomly assigned to an anodal (n=15) or sham (n=15) stimulation group. First, subjects performed the grip task with their dominant hand while following the pace of a metronome. Afterwards, subjects trained on the task, at their own pace, over 5 consecutive days while receiving sham or anodal tDCS over M1. After training, subjects performed de novo the metronome-assisted task. The change in performance between the pre and post metronome-assisted task was used to assess the impact of the grip task and tDCS on learning. RESULTS: Anodal tDCS over M1 had a significant effect on the speed-accuracy tradeoff function. The anodal tDCS group showed significantly greater improvement in performance (39.28±15.92%) than the sham tDCS group (24.06±16.35%) on the metronome-assisted task, t(28)=2.583, P=0.015 (effect size d=0.94). CONCLUSIONS: Anodal tDCS is effective in promoting grip motor learning in healthy individuals. Further studies are warranted to test its potential use for the rehabilitation of fine motor skills in stroke patients.

The Effects of Acute Intense Physical Exercise on Postural Stability in Children With Cerebral Palsy.

This study evaluated the effects of intense physical exercise on postural stability of children with cerebral palsy (CP). Center of pressure (CoP) was measured in 9 typically developing (TD) children and 8 with CP before and after a maximal aerobic shuttle-run test (SRT) using a single force plate. Anteroposterior and mediolateral sway velocities, sway area, and sway regularity were calculated from the CoP data and compared between pre- and postexercise levels and between groups. Children with CP demonstrated significantly higher pre-SRT CoP velocities than TD children in the sagittal (18.6 ± 7.6 vs. 6.75 1.78 m/s) and frontal planes (15.4 ± 5.3 vs. 8.04 ± 1.51 m/s). Post-SRT, CoP velocities significantly increased for children with CP in the sagittal plane (27.0 ± 1.2 m/s), with near-significant increases in the frontal plane (25.0 ± 1.5m/s). Similarly, children with CP evidenced larger sway areas than the TD children both pre- and postexercise. The diminished postural stability in children with CP after short but intense physical exercise may have important implications including increased risk of falls and injury.

Feeling but not caring: empathic alteration in narcissistic men with high psychopathic traits.

Psychopathy is a personality disorder characterized by specific interpersonal-affective deficits and social deviance often marked by reduced empathy and decreased affective response to the suffering of others. However, recent findings in community samples suggest that the somatosensory resonance to other's pain measured with electroencephalography (EEG) is increased by psychopathic traits. This study aimed at comparing both the response to physical pain and the observation of pain being inflicted to another person in individuals with clinically significant psychopathic traits, namely patients with severe narcissistic personality disorder (NPD, n=11), and community controls (CC, n=13). The gating of somatosensory responses to a tactile steady-state stimulation (25 Hz) during the observation of pain-evoking and non-painful visual stimuli of hands was measured using EEG. Pain thresholds were assessed with a quantitative sensory testing (QST) battery. NPD compared with CC subjects showed similar thermal pain thresholds, but significantly higher pain pressure thresholds (PPT). Significantly greater somatosensory gating (SG) during the anticipation and the observation of pain in others was observed in NPD compared with CC subjects, but this difference was not associated with differences in self-pain perception. SG to pain observation was positively correlated with the Impulsivity-Egocentricity (IE) dimension of psychopathy. These findings demonstrated a stronger somatosensory resonance in the high psychopathic trait NPD group that suggests an increased somatic representation of observed pain despite lower dispositional empathy.

Haptic two-dimensional angle categorization and discrimination.

This study examined the extent to which haptic perception of two-dimensional (2-D) shape is modified by the design of the perceptual task (single-interval categorization vs. two-interval discrimination), the orientation of the angles in space (oblique vs. horizontal), and the exploration strategy (one or two passes over the angle). Subjects (n = 12) explored 2-D angles using the index finger of the outstretched arm. In the categorization task, subjects scanned individual angles, categorizing each as "large" or "small" (2 angles presented in each block of trials; range 80° vs. 100° to 89° vs. 91°; implicit standard 90°). In the discrimination task, a pair of angles was scanned (standard 90°; comparison 91-103°) and subjects identified the larger angle. The threshold for 2-D angle categorization was significantly lower than for 2-D angle discrimination, 4° versus 7.2°. Performance in the categorization task did not vary with either the orientation of the angles (horizontal vs. oblique, 3.9° vs. 4°) or the number of passes over the angle (1 vs. 2 passes, 3.9° vs. 4°). We suggest that the lower threshold with angle categorization likely reflects the reduced cognitive demands of this task. We found no evidence for a haptic oblique effect (higher threshold with oblique angles), likely reflecting the presence of an explicit external frame of reference formed by the intersection of the two bars forming the 2-D angles. Although one-interval haptic categorization is a more sensitive method for assessing 2-D haptic angle perception, perceptual invariances for exploratory strategy and angle orientation were, nevertheless, task-independent.

The influence of visual perspective on the somatosensory steady-state response during pain observation.

The observation and evaluation of other's pain activate part of the neuronal network involved in the actual experience of pain, including those regions subserving the sensori-discriminative dimension of pain. This was largely interpreted as evidence showing that part of the painful experience can be shared vicariously. Here, we investigated the effect of the visual perspective from which other people's pain is seen on the cortical response to continuous 25 Hz non-painful somatosensory stimulation (somatosensory steady-state response: SSSR). Based on the shared representation framework, we expected first-person visual perspective (1PP) to yield more changes in cortical activity than third-person visual perspective (3PP) during pain observation. Twenty healthy adults were instructed to rate a series of pseudo-dynamic pictures depicting hands in either painful or non-painful scenarios, presented either in 1PP (0-45° angle) or 3PP (180° angle), while changes in brain activity was measured with a 128-electode EEG system. The ratings demonstrated that the same scenarios were rated on average as more painful when observed from the 1PP than from the 3PP. As expected from previous works, the SSSR response was decreased after stimulus onset over the left caudal part of the parieto-central cortex, contralateral to the stimulation side. Moreover, the difference between the SSSR was of greater amplitude when the painful situations were presented from the 1PP compared to the 3PP. Together, these results suggest that a visuospatial congruence between the viewer and the observed scenarios is associated with both a higher subjective evaluation of pain and an increased modulation in the somatosensory representation of observed pain. These findings are discussed with regards to the potential role of visual perspective in pain communication and empathy.

The modulation of somatosensory resonance by psychopathic traits and empathy.

A large number of neuroimaging studies have shown neural overlaps between first-hand experiences of pain and the perception of pain in others. This shared neural representation of vicarious pain is thought to involve both affective and sensorimotor systems. A number of individual factors are thought to modulate the cerebral response to other's pain. The goal of this study was to investigate the impact of psychopathic traits on the relation between sensorimotor resonance to other's pain and self-reported empathy. Our group has previously shown that a steady-state response to non-painful stimulation is modulated by the observation of other people's bodily pain. This change in somatosensory response was interpreted as a form of somatosensory gating (SG). Here, using the same technique, SG was compared between two groups of 15 young adult males: one scoring very high on a self-reported measure of psychopathic traits [60.8 ± 4.98; Levenson's Self-Report Psychopathy Scale (LSRP)] and one scoring very low (42.7 ± 2.94). The results showed a significantly greater reduction of SG to pain observation for the high psychopathic traits group compared to the low psychopathic traits group. SG to pain observation was positively correlated with affective and interpersonal facet of psychopathy in the whole sample. The high psychopathic traits group also reported lower empathic concern (EC) scores than the low psychopathic traits group. Importantly, primary psychopathy, as assessed by the LSRP, mediated the relation between EC and SG to pain observation. Together, these results suggest that increase somatosensory resonance to other's pain is not exclusively explained by trait empathy and may be linked to other personality dimensions, such as psychopathic traits.

I am touched by your pain: limb-specific modulation of the cortical response to a tactile stimulation during pain observation.

UNLABELLED: The observation of pain in other individuals is known to impact the cerebral activity in regions dedicated to one's nociception, as well as the behavior toward the person in pain. However, it remains unclear whether this shared representation for pain modulates somatosensory processing to nonpainful stimuli and whether this modulation is limb specific. Twenty right-handed healthy participants viewed a series of pictures depicting right hands or right feet in painful or nonpainful situations while light repetitive (25 Hz) mechanical stimuli were applied to the hand. The cortical excitability to these nonpainful stimuli was measured through the energy in the 25-Hz frequency band of electroencephalographic data. Following picture onset, a combination of nonspecific and specific modulation of cortical excitability was found. The former was widespread over the parieto-central region and likely related to factors such as attention. The latter was mostly restricted to 3 electrodes over the parietal cortex contralateral to the stimulation of the hand, and was specifically associated with the observation of others' hand in painful scenarios. This result confirms that the observation of pain can modulate somatosensory cortical excitability in an effector-specific way. The findings add to the accumulating evidence that other people's somatic pain is mapped onto the observer's sensori-motor system and offers a new paradigm to investigate potential neurophysiological changes in care providers who are often overexposed to others' pain. PERSPECTIVE: This electroencephalography study demonstrates with a quick, easily implementable, and noninvasive paradigm that the change in cortical somatosensory excitability during pain observation is limb-specific, and confirms from a neuroscience perspective that being exposed to others' pain implies more than the sharing of an affective experience.

Is somatosensory excitability more affected by the perspective or modality content of motor imagery?

Beneficial effects of mental practice likely arise because motor imagery involves largely similar neural networks as physical execution of the same movement. While it is known that the involvement of the motor system is favoured by focusing on the kinaesthetic modality and by the first person perspective, little is known about the impact of these factors on the somatosensory system. The present paper examines the effects on the somatosensory excitability of both perspective (the point of view of the person imagining a motor act) and modality (visual versus kinaesthetic) during mental practice. Seventeen healthy subjects participated. Quality of mental practice was controlled using chronometric tests and a subjective questionnaire. Excitability of the somatosensory system was assessed through the steady-state electroencephalographical response to a continuous train of electrical stimuli applied to the radial nerve, at the same time subjects were instructed to perform one of five tasks designed to separate the effects of perspective, modality and motor versus non-motor imagery. Kinaesthetic motor imagery exerts the largest effect on somatosensory excitability whereas visual motor imageries (1st and 3rd person perspectives) produce the same lower effect that static visual imagery does. Strikingly, specific effect of kinaesthetic motor imagery correlates with the selfselected speed to imagine and execute the same movement. These findings suggest a key role of the kinaesthetic content of motor imagery in recruiting the sensorimotor system.

Modulation of the response to a somatosensory stimulation of the hand during the observation of manual actions.

Observation of hand movements has been repeatedly demonstrated to increase the excitability of the motor cortical representation of the hand. Little attention, however, has been devoted to its effect on somatosensory processing. Movement execution is well known to decrease somatosensory cortical excitability, a phenomenon termed 'gating'. As executed and observed actions share common cortical representations, we hypothesized that action observation (hand movements) should also modulate the cortical response to sensory stimulation of the hand. Seventeen healthy subjects participated in these experiments in which electroencephalographic (EEG) recordings of the somatosensory steady-state response (SSSR) were obtained. The SSSR provides a continuous measure of somatosensory processing. Recordings were made during a baseline condition and five observation conditions in which videos showed either a: (1) hand action; (2) passive stimulation of a hand; (3) static hand; (4) foot action; or (5) static object. The method employed consisted of applying a continuous 25 Hz vibratory stimulation to the index finger during the six conditions and measuring potential gating effects in the SSSR within the 25 Hz band (corresponding to the stimulation frequency). A significant effect of condition was found over the contralateral parietal cortex. Observation of hand actions resulted in a significant gating effect when compared to baseline (average gating of 22%). Observation of passive touch of the hand also gated the response (17% decrease). In conclusion, the results show that viewing a hand performing an action or being touched interferes with the processing of somatosensory information arising from the hand.

Listening in silence activates auditory areas: a functional magnetic resonance imaging study.

Directing attention to some acoustic features of a sound has been shown repeatedly to modulate the stimulus-induced neural responses. On the contrary, little is known about the neurophysiological impact of auditory attention when the auditory scene remains empty. We performed an experiment in which subjects had to detect a sound emerging from silence (the sound was detectable after different durations of silence). Two frontal activations (right dorsolateral prefrontal and inferior frontal) were found, regardless of the side where sound was searched for, consistent with the well established role of these regions in attentional control. The main result was that the superior temporal cortex showed activations contralateral to the side where sound was expected to be present. The area extended from the vicinity of Heschl's gyrus to the surrounding areas (planum temporale/anterior lateral areas). The effect consisted of both an increase in the response to a sound delivered after attention was directed to detect its emergence and a baseline shift during the silent period. Thus, in absence of any acoustic stimulus, the search for an auditory input was found to activate the auditory cortex.

Listening to a walking human activates the temporal biological motion area.

A vivid perception of a moving human can be evoked when viewing a few point-lights on the joints of an invisible walker. This special visual ability for biological motion perception has been found to involve the posterior superior temporal sulcus (STSp). However, in everyday life, human motion can also be recognized using acoustic cues. In the present study, we investigated the neural substrate of human motion perception when listening to footsteps, by means of a sparse sampling functional MRI design. We first showed an auditory attentional network that shares frontal and parietal areas previously found in visual attention paradigms. Second, an activation was observed in the auditory cortex (Heschl's gyrus and planum temporale), likely to be related to low-level sound processing. Most strikingly, another activation was evidenced in a STSp region overlapping the temporal biological motion area previously reported using visual input. We thus propose that a part of the STSp region might be a supramodal area involved in human motion recognition, irrespective of the sensory modality input.

Haptic shape discrimination in humans: insight into haptic frames of reference.

This study investigates how a change in the physical relation between objects (two-dimensional, 2-D, angles) and a subject, as well as scanning conditions, modify the ability to discriminate small changes in 2-D shape. Subjects scanned pairs of angles (90 masculine standard; 91 masculine-103 masculine comparison angles) with the right index finger of the out-stretched arm, identifying the larger of each pair. When joint rotation was restricted to the shoulder, the discrimination threshold significantly increased when the angles were explored with the shoulder in a more eccentric position rather than closer to the midline (60 masculine versus 30 masculine to the right). This result was attributed to changes in proprioceptive sensitivity, since explorations restricted to distal joints (wrist/second metacarpophalangeal joint) showed no change with shoulder position. The results showed, moreover, that discrimination threshold was similar for distal and proximal joints when the delay between scanning the pairs of angles was long (15 s). This observation suggests that regional variations in proprioceptive acuity (proximal>distal) may reflect an adaptation to generate an invariant central representation of haptic shape. Using a shorter interscan delay (5 s), a position-dependent increase in discrimination threshold was revealed for distal explorations, an effect that disappeared when the head was turned in the direction of the unseen angle (vision occluded). We suggest that these results can be explained by the existence of two competing egocentric frames of reference with different time courses, one of short duration that is centred on the arm/hand, and a second of longer duration centred on the head. At the short delay, the reference frames interacted to distort the haptic representation when they were misaligned. This distortion was resolved at the long delay, possibly through suppression of the arm/hand-centred reference frame.

Haptic discrimination of object shape in humans: two-dimensional angle discrimination.

The human ability to recognize objects on the basis of their shape, as defined by active exploratory movements, is dependent on sensory feedback from mechanoreceptors located both in the skin and in deep structures ( haptic feedback). Surprisingly, we have little information about the mechanisms for integrating these different signals into a single sensory percept. With the eventual aim of studying the underlying central neural mechanisms, we developed a shape discrimination test that required active exploration of objects, but was restricted to one component of shape, two-dimensional (2D) angles. The angles were machined from 1-cm-thick Plexiglas, and consisted of two 8-cm-long arms that met to form an angle of 90 degrees (standard) or 91 degrees to 103 degrees (comparison angles). Subjects scanned pairs of angles with the index finger of the outstretched arm and identified the larger angle of each pair explored. Discrimination threshold (75% correct) was 4.7 degrees (range 0.7 degrees to 12.1 degrees), giving a precision of 5.2% (0.8-13.4%: difference/standard). Repeated blocks of trials, either in the same session or on different days, had no effect on discrimination threshold. In contrast, the motor strategy was partly modified: scanning speed increased but dwell-time at the intersection did not change. Finally, 2D angle discrimination was not significantly modified by rotating the orientation of one of the angles in the pair (0 degrees, 4 degrees or 8 degrees rotation towards the midline, in the vertical plane), providing evidence that subjects evaluated each angle independently in each trial. Subject reports indicated that they relied on cutaneous feedback from the exploring digit (amount of compression of the finger at the angle) and mental images of the angles, most likely arising from proprioceptive information (from the shoulder) generated during the to-and-fro scans over the angle. In terms of shoulder angles, the mean discrimination threshold here was 0.54 degrees (range 0.08 degrees to 1.36 degrees). These values are lower than previous estimates of position sense at the shoulder. In light of the subjects' strategies, it therefore seems likely that both cutaneous and proprioceptive (including both dynamic and static position-related signals) feedback contributed to the haptic discrimination of 2D angles.

Haptic discrimination of object shape in humans: contribution of cutaneous and proprioceptive inputs.

Using two-dimensional (2D) angles composed of two straight, 8-cm-long arms that formed an angle, we investigated the importance of cutaneous feedback from the exploring index finger, and proprioceptive feedback from the shoulder (scanning movements made with the outstretched arm), to the human ability to discriminate small differences in the angles. Using a two-alternative forced-choice paradigm, subjects identified the larger angle in each pair explored (standard angle, 90 degrees; comparison angles, 91 degrees to 103 degrees). Subjects were tested under four experimental conditions: (1) active touch (reference condition); (2) active touch with digital anaesthesia; (3) passive touch (a computer-controlled device displaced the angle under the subject's immobile digit); and (4) passive touch with digital anaesthesia. When only proprioceptive feedback from the shoulder was available (condition 2), there was a significant increase in discrimination threshold, from 4.0 degrees in the reference condition (condition 1) to 7.2 degrees, indicating that cutaneous feedback from the exploring digit contributed to task performance. When only cutaneous feedback from the finger was available (condition 3), there was also a significant increase in threshold from 4.2 degrees in the active condition to 8.7 degrees. This suggested that proprioceptive feedback from the shoulder, potentially from a variety of deep (muscle and joint) but also cutaneous receptors, contributed to the ability to discriminate small changes in 2D angles. When both sources of feedback were eliminated (condition 4), subjects were unable to discriminate even the largest difference presented (13 degrees). The results suggest that this sensory task is truly an integrative task drawing on sensory information from two different submodalities and so, following the definition of Gibson, is haptic in nature. The results are discussed in relation to the potential neural mechanisms that might underlie a task that requires integration across two anatomically separate body parts and two distinct modalities.