Virtual Reality Social Prediction Improvement and Rehabilitation Intensive Training (VR-SPIRIT) for paediatric patients with congenital cerebellar diseases: study protocol of a randomised controlled trial

New Insights into the Neuropsychological Profile and Intellectual Quotient Variability in Joubert Syndrome Compared to Other Congenital Cerebellar Malformations

The neuropsychological characteristics of the cerebellar cognitive affective syndrome (CCAS) in congenital, non-progressive malformations of the cerebellum have been scarcely investigated, and even less is known for Joubert syndrome (JS), an inherited, non-progressive cerebellar ataxia characterized by the so-called molar tooth sign. The few studies on this topic reported inconsistent results about intellectual functioning and specific neuropsychological impairments. The aim of this research is to examine the neuropsychological profile of JS compared to other congenital cerebellar malformations (CM), considering individual variability of intellectual quotient (IQ) in the two groups. Fourteen patients with JS and 15 patients with CM aged 6-25 years were tested through a comprehensive, standardized neuropsychological battery. Their scores in the neuropsychological domains were inspected through descriptive analysis and compared by mean of MANOVA and ANOVA models, then replicated inserting IQ as covariate. The two groups showed a largely overlapping neuropsychological profile, consistent with CCAS. However, the JS group showed worse performance in visual-spatial memory compared to CM patients, although this difference was mitigated when considering IQ. These findings highlight a divergence between JS and other CM in visual-spatial memory, which might suggest a critical role of the cerebellum in recalling task-relevant memories and might inform rehabilitative interventions.

Excitatory cerebellar transcranial direct current stimulation boosts the leverage of prior knowledge for predicting actions

The cerebellum causally supports social processing by generating internal models of social events based on statistical learning of behavioral regularities. However, whether the cerebellum is only involved in forming or also in using internal models for the prediction of forthcoming actions is still unclear. We used cerebellar transcranial Direct Current Stimulation (ctDCS) to modulate the performance of healthy adults in using previously learned expectations in an action prediction task. In a first learning phase of this task, participants were exposed to different levels of associations between specific actions and contextual elements, to induce the formation of either strongly or moderately informative expectations. In a following testing phase, which assessed the use of these expectations for predicting ambiguous (i.e. temporally occluded) actions, we delivered ctDCS. Results showed that anodic, compared to sham, ctDCS boosted the prediction of actions embedded in moderately, but not strongly, informative contexts. Since ctDCS was delivered during the testing phase, that is after expectations were established, our findings suggest that the cerebellum is causally involved in using internal models (and not just in generating them). This encourages the exploration of the clinical effects of ctDCS to compensate poor use of predictive internal models for social perception.

Neurorestorative effects of cerebellar transcranial direct current stimulation on social prediction of adolescents and young adults with congenital cerebellar malformations

BACKGROUND

Converging evidence points to impairments of the predictive function exerted by the cerebellum as one of the causes of the social cognition deficits observed in patients with cerebellar disorders.

OBJECTIVE

We tested the neurorestorative effects of cerebellar transcranial direct current stimulation (ctDCS) on the use of contextual expectations to interpret actions occurring in ambiguous sensory sceneries in a sample of adolescents and young adults with congenital, non-progressive cerebellar malformation (CM).

METHODS

We administered an action prediction task in which, in an implicit-learning phase, the probability of co-occurrence between actions and contextual elements was manipulated to form either strongly or moderately informative expectations. Subsequently, in a testing phase, we probed the use of these contextual expectations for predicting ambiguous (i.e., temporally occluded) actions. In a sham-controlled, within-subject design, participants received anodic or sham ctDCS during the task.

RESULTS

Anodic ctDCS, compared to sham, improved patients' ability to use contextual expectations to predict the unfolding of actions embedded in moderately, but not strongly, informative contexts.

CONCLUSIONS

These findings corroborate the role of the cerebellum in using previously learned contextual associations to predict social events and document the efficacy of ctDCS to boost social prediction in patients with congenital cerebellar malformation. The study encourages the further exploration of ctDCS as a neurorestorative tool for the neurorehabilitation of social cognition abilities in neurological, neuropsychiatric, and neurodevelopmental disorders featured by macro- or micro-structural alterations of the cerebellum.

Contextual Priors Shape Action Understanding before and beyond the Unfolding of Movement Kinematics

Previous studies have shown that contextual information may aid in guessing the intention underlying others' actions in conditions of perceptual ambiguity. Here, we aimed to evaluate the temporal deployment of contextual influence on action prediction with increasing availability of kinematic information during the observation of ongoing actions. We used action videos depicting an actor grasping an object placed on a container to perform individual or interpersonal actions featuring different kinematic profiles. Crucially, the container could be of different colors. First, in a familiarization phase, the probability of co-occurrence between each action kinematics and color cues was implicitly manipulated to 80% and 20%, thus generating contextual priors. Then, in a testing phase, participants were asked to predict action outcome when the same action videos were occluded at five different timeframes of the entire movement, ranging from when the actor was still to when the grasp of the object was fully accomplished. In this phase, all possible action-contextual cues' associations were equally presented. The results showed that for all occlusion intervals, action prediction was more facilitated when action kinematics deployed in high- than low-probability contextual scenarios. Importantly, contextual priors shaped action prediction even in the latest occlusion intervals, where the kinematic cues clearly unveiled an action outcome that was previously associated with low-probability scenarios. These residual contextual effects were stronger in individuals with higher subclinical autistic traits. Our findings highlight the relative contribution of kinematic and contextual information to action understanding and provide evidence in favor of their continuous integration during action observation.

Virtual reality and augmented reality as strategies for teaching social skills to individuals with intellectual disability: A systematic review

Virtual reality (VR) and augmented reality (AR) programs have proliferated significantly in recent years and they are finding their way into different educational and therapeutic purposes. This systematic review aims at analyzing the virtual reality and augmented reality programs designed to promote the development of social skills in individuals with intellectual disability. Searches were carried out in the Scopus, Science Direct, Springer and Web of Science databases in the period from 2005 to 2020. A total of six articles met the inclusion criteria. A descriptive data analysis was performed. The results show that the clinical profile of the individuals who participated in the interventions is diverse. It can be concluded that there is some scientific evidence that points to the usefulness of VR and AR in the development of intervention programs to improve the social skills of individuals diagnosed with developmental deficits. However, it is necessary to acknowledge methodological limitations such as the lack of control groups, follow-up measures and of generalization of the results.

Cognitive predictors of Social processing in congenital atypical development

According to current accounts of social cognition, the emergence of verbal and non-verbal components of social perception might rely on the acquisition of different cognitive abilities. These components might be differently sensitive to the pattern of neuropsychological impairments in congenital neurodevelopmental disorders. Here, we explored the association between social and non-social cognitive domains by administering subtests of the NEPSY-II battery to 92 patients with Intellectual and Developmental Disability (IDD). Regardless the level of intellectual functioning and presence of congenital brain malformations, results revealed that visuospatial skills predicted emotion recognition and verbal component of Theory of Mind, whereas imitation predicted the non-verbal one. Future interventions might focus on spatial and sensorimotor abilities to boost the development of social cognition in IDD.

Remote cognitive training for children with congenital brain malformation or genetic syndrome: a scoping review

Increased attention is arising on the delivery of remote cognitive interventions, which allow performing exercises in everyday settings, favouring rehabilitation continuity. The present study offers an overview of remote cognitive training programs for children with congenital brain malformation or genetic syndrome affecting the central nervous system, included in papers published in the time period 2011-2021. A total of 13 records was found and discussed including efficacy studies, feasibility studies and study protocols. Many studies have focused on a specific diagnosis, such as cerebral palsy, Down Syndrome, Fragile X Syndrome, while no or little evidence has been gathered on more rare diseases or brain malformations. Interventions were found to generate benefits on some cognitive functions, but problems with adherence were highlighted, especially due to excessive cognitive load from the training or clinical comorbidities. Conclusions remain tentative due to heterogeneity in training, study and patients characteristics, and methodological limitations of studies.

Is Social Training Delivered with a Head-Mounted Display Suitable for Patients with Hereditary Ataxia?

Social cognition is fundamental in everyday life to understand "others' behavior", which is a key feature of social abilities. Previous studies demonstrated the efficacy of a rehabilitative intervention in semi-immersive virtual reality (VR) controlled by whole-body motion to improve the ability of patients with cerebellar disorders to predict others' intentions (VR-SPIRIT). Patients with severe ataxia that have difficulties at multiple levels of social processing could benefit from this intervention in terms of improving their social prediction skills, but they may have difficulties in controlling VR with whole-body movements. Therefore, we implemented VR-SPIRIT on a wearable, affordable, and easy-to-use technology, such as the Oculus Quest, a head-mounted display. The aim of this work was to evaluate the usability and tolerability of this VR application. We recruited 10 patients (37.7 ± 14.8 years old, seven males) with different types of hereditary ataxia who performed a single VR-SPIRIT session using the Oculus Quest viewer. After the session, patients answered a series of questionnaires to investigate the overall usability of the system and its potential effects in terms of cyber sickness. The preliminary results demonstrated system usability and tolerability. Indeed, only three patients did not complete the session due to different problems (dizziness, nausea, and boredom). In future studies, more patients will be enrolled to assess the effectiveness of the application, paving the way for the implementation of social training that can also be delivered at home.

Cognitive Dysfunction following Cerebellar Stroke: Insights Gained from Neuropsychological and Neuroimaging Research

Although the cerebellum has been consistently noted in the process of cognition, the pathophysiology of this link is still under exploration. Cerebellar stroke, in which the lesions are focal and limited, provides an appropriate clinical model disease for studying the role of the cerebellum in the cognitive process. This review article targeting the cerebellar stroke population (1) describes a cognitive impairment profile, (2) identifies the cerebellar structural alterations linked to cognition, and (3) reveals possible mechanisms of cerebellar cognition using functional neuroimaging. The data indicates the disruption of the cerebro-cerebellar loop in cerebellar stroke and its contribution to cognitive dysfunctions. And the characteristic of cognitive deficits are mild, span a broad spectrum, dominated by executive impairment. The consideration of these findings could contribute to deeper and more sophisticated insights into the cognitive function of the cerebellum and might provide a novel approach to cognitive rehabilitation. The goal of this review is to spread awareness of cognitive impairments in cerebellar disorders.

New Horizons on Non-invasive Brain Stimulation of the Social and Affective Cerebellum

The cerebellum is increasingly attracting scientists interested in basic and clinical research of neuromodulation. Here, we review available studies that used either transcranial magnetic stimulation (TMS) or transcranial direct current stimulation (tDCS) to examine the role of the posterior cerebellum in different aspects of social and affective cognition, from mood regulation to emotion discrimination, and from the ability to identify biological motion to higher-level social inferences (mentalizing). We discuss how at the functional level the role of the posterior cerebellum in these different processes may be explained by a generic prediction mechanism and how the posterior cerebellum may exert this function within different cortico-cerebellar and cerebellar limbic networks involved in social cognition. Furthermore, we suggest to deepen our understanding of the cerebro-cerebellar circuits involved in different aspects of social cognition by employing promising stimulation approaches that have so far been primarily used to study cortical functions and networks, such as paired-pulse TMS, frequency-tuned stimulation, state-dependent protocols, and chronometric TMS. The ability to modulate cerebro-cerebellar connectivity opens up possible clinical applications for improving impairments in social and affective skills associated with cerebellar abnormalities.