Alexandra P. Key

'Hungry Eyes': visual processing of food images in adults with Prader-Willi syndrome.

BACKGROUND Prader-Willi syndrome (PWS) is a genetic disorder associated with intellectual disabilities, compulsivity, hyperphagia and increased risks of life-threatening obesity. Food preferences in people with PWS are well documented, but research has yet to focus on other properties of food in PWS, including composition and suitability for consumption. It is also unclear how food perceptions differ across the two major genetic subtypes of PWS. METHODS This study examined neural responses to food stimuli in 17 adults with PWS, nine with paternal deletions and eight with maternal uniparental disomy (UPD), and in nine age-matched typical controls. Visual event-related potentials (ERPs) were recorded in response to food images varying in food composition and suitability for consumption during a passive viewing paradigm. RESULTS Group differences were observed for the N1 and P3 responses reflecting perceptual categorisation and motivational relevance respectively. The deletion group categorised food stimuli in terms of composition while the UPD group performed more similar to the controls, and focused on the suitability of food for consumption. Individual differences in N1 amplitude correlated with body mass index and scores on the Hyperphagia Questionnaire. CONCLUSION Differences are seen in how people with PWS because of deletion or UPD perceive visual food stimuli even within the first milliseconds of stimuli exposure. Implications are discussed for in vivo food behaviours and for future ERP or neuroimaging studies on hunger, satiety and food perception in PWS.

Cortical speech sound differentiation in the neonatal intensive care unit predicts cognitive and language development in the first 2 years of life.

Neurodevelopmental delay in childhood is common in infants born preterm, but is difficult to predict before infants leave the neonatal intensive care unit (NICU). We hypothesized that event‐related potential (ERP) methodology characterizing the cortical differentiation of speech sounds in hospitalized infants would predict cognitive and language outcomes during early childhood.

Social and emotional processing in Prader-Willi syndrome: genetic subtype differences.

BackgroundPeople with Prader-Willi syndrome (PWS) demonstrate social dysfunction and increased risk of autism spectrum disorder, especially those with the maternal uniparental disomy (mUPD) versus paternal deletion genetic subtype. This study compared the neural processing of social (faces) and nonsocial stimuli, varying in emotional valence, across genetic subtypes in 24 adolescents and adults with PWS.MethodsUpright and inverted faces, and nonsocial objects with positive and negative emotional valence were presented to participants with PWS in an oddball paradigm with smiling faces serving as targets. Behavioral and event-related potential (ERP) data were recorded.ResultsThere were no genetic subtype group differences in accuracy, and all participants performed above chance level. ERP responses revealed genetic subtype differences in face versus object processing. In those with deletions, the face-specific posterior N170 response varied in size for face stimuli versus inverted faces versus nonsocial objects. Persons with mUPD generated N170 of smaller amplitude and showed no stimulus differentiation. Brain responses to emotional content did not vary by subtype. All participants elicited larger posterior and anterior late positive potential responses to positive objects than to negative objects. Emotion-related differences in response to faces were limited to inverted faces only in the form of larger anterior late positive potential amplitudes to negative emotions over the right hemisphere. Detection of the target smiling faces was evident in the increased amplitude of the frontal and central P3 responses but only for inverted smiling faces.ConclusionPersons with the mUPD subtype of PWS may show atypical face versus object processes, yet both subtypes demonstrated potentially altered processing, attention to and/or recognition of faces and their expressions.

The Dual Nature of Early-Life Experience on Somatosensory Processing in the Human Infant Brain

Every year, 15 million preterm infants are born, and most spend their first weeks in neonatal intensive care units (NICUs) [1]. Although essential for the support and survival of these infants, NICU sensory environments are dramatically different from those in which full-term infants mature and thus likely impact the development of functional brain organization [2]. Yet the integrity of sensory systems determines effective perception and behavior [3, 4]. In neonates, touch is a cornerstone of interpersonal interactions and sensory-cognitive development [5-7]. NICU treatments used to improve neurodevelopmental outcomes rely heavily on touch [8]. However, we understand little of how brain maturation at birth (i.e., prematurity) and quality of early-life experiences (e.g., supportive versus painful touch) interact to shape the development of the somatosensory system [9]. Here, we identified the spatial, temporal, and amplitude characteristics of cortical responses to light touch that differentiate them from sham stimuli in full-term infants. We then utilized this data-driven analytical framework to show that the degree of prematurity at birth determines the extent to which brain responses to light touch (but not sham) are attenuated at the time of discharge from the hospital. Building on these results, we showed that, when controlling for prematurity and analgesics, supportive experiences (e.g., breastfeeding, skin-to-skin care) are associated with stronger brain responses, whereas painful experiences (e.g., skin punctures, tube insertions) are associated with reduced brain responses to the same touch stimuli. Our results shed crucial insights into the mechanisms through which common early perinatal experiences may shape the somatosensory scaffolding of later perceptual, cognitive, and social development.

Attentional disengagement in adults with Williams syndrome

Williams syndrome (WS) is a neurodevelopmental disorder characterized by a distinctive behavioral and cognitive profile, including widespread problems with attention. However, the specific nature of their attentional difficulties, such as inappropriate attentional allocation and/or poor attentional disengagement abilities, has yet to be elucidated. Furthermore, it is unknown if there is an underlying difficulty with the temporal dynamics of attention in WS or if their attentional difficulties are task-dependent, because previous studies have examined attention in established areas of deficit and atypicality (specifically, visuospatial and face processing). In this study, we examined attentional processing in 14 adults with WS (20-59 years) and 17 typically developing controls (19-39 years) using an attentional blink (AB) paradigm. The AB is the decreased ability to detect a second target when it is presented in close proximity to an initial target. Overall, adults with WS had an AB that was prolonged in duration, but no different in magnitude, compared with typically developing control participants. AB performance was not explained by IQ, working memory, or processing speed in either group. Thus, results suggest that the attention problems in WS are primarily due to general attentional disengagement difficulties rather than inappropriate attentional allocation.

A Step towards EEG-based brain computer interface for autism intervention.

Autism Spectrum Disorder (ASD) is a prevalent and costly neurodevelopmental disorder. Individuals with ASD often have deficits in social communication skills as well as adaptive behavior skills related to daily activities. We have recently designed a novel virtual reality (VR) based driving simulator for driving skill training for individuals with ASD. In this paper, we explored the feasibility of detecting engagement level, emotional states, and mental workload during VR-based driving using EEG as a first step towards a potential EEG-based Brain Computer Interface (BCI) for assisting autism intervention. We used spectral features of EEG signals from a 14-channel EEG neuroheadset, together with therapist ratings of behavioral engagement, enjoyment, frustration, boredom, and difficulty to train a group of classification models. Seven classification methods were applied and compared including Bayes network, naïve Bayes, Support Vector Machine (SVM), multilayer perceptron, K-nearest neighbors (KNN), random forest, and J48. The classification results were promising, with over 80% accuracy in classifying engagement and mental workload, and over 75% accuracy in classifying emotional states. Such results may lead to an adaptive closed-loop VR-based skill training system for use in autism intervention.

Early childhood constraint therapy for sensory/motor impairment in cerebral palsy: a randomised clinical trial protocol

Introduction Cerebral palsy (CP) is the most common physical disability in childhood. It is a disorder resulting from sensory and motor impairments due to perinatal brain injury, with lifetime consequences that range from poor adaptive and social function to communication and emotional disturbances. Infants with CP have a fundamental disadvantage in recovering motor function: they do not receive accurate sensory feedback from their movements, leading to developmental disregard. Constraint-induced movement therapy (CIMT) is one of the few effective neurorehabilitative strategies shown to improve upper extremity motor function in adults and older children with CP, potentially overcoming developmental disregard. Methods and analysis This study is a randomised controlled trial of children 12–24 months corrected age studying the effectiveness of CIMT combined with motor and sensory-motor interventions. The study population will comprise 72 children with CP and 144 typically developing children for a total of N=216 children. All children with CP, regardless of group allocation will continue with their standard of care occupational and physical therapy throughout the study. The research material collected will be in the form of data from high-density array event-related potential scan, standardised assessment scores and motion analysis scores. Ethics and dissemination The study protocol was approved by the Institutional Review Board. The findings of the trial will be disseminated through peer-reviewed journals and scientific conferences. Trial registration number NCT02567630.

Examining the relationship between face processing and social interaction behavior in children with and without autism spectrum disorder

BackgroundChildren with autism spectrum disorder (ASD) show impairment in reciprocal social communication, which includes deficits in social cognition and behavior. Since social cognition and social behavior are considered to be interdependent, it is valuable to examine social processes on multiple levels of analysis. Neuropsychological measures of face processing often reveal deficits in social cognition in ASD including the ability to identify and remember facial information. However, the extent to which neuropsychological measures are associated with or predictive of real-world social behavior is unclear.MethodsThe study investigated 66 children (ASD 34, typically developing (TD) 32) using neuropsychological measures of face processing (identity, affect, and memory). Children also participated in a peer interaction paradigm, which allowed observation and coding of natural social interaction behaviors during play with peers (e.g., Self-Play, Cooperative Play, Verbal Bout). ANCOVA, regression, and correlation models analyzed between-group differences, the ability of neuropsychological measures to predict social behavior, and the strength of the associations.ResultsBetween-group differences were shown on Memory for Faces Delayed and the peer interaction variables Self-Play and Verbal Bout. Regression models indicated that Memory for Faces Delayed predicted the amount of Self-Play, Equipment use alone, and Cooperative Play with peers on the playground. Autism symptomology only predicted verbal exchange with peers.ConclusionsFace memory strongly predicts relevant social engagement patterns in both children with and without ASD. Impairment in facial memory is associated with reduced ‘real-world’ social interaction and more self-play, whereas higher performance in face memory predicts more cooperative play. Results highlight the strong connection between face memory and reciprocal social interaction, suggesting that improvement in one may benefit the other.

Feasibility of event-related potential methodology to evaluate changes in cortical processing after rehabilitation in children with cerebral palsy: A pilot study

This study examined the feasibility of using event-related potentials (ERPs) to measure changes in cortical processing following an established rehabilitative intervention (constraint-induced movement therapy, CIMT) for children with cerebral palsy (CP). Sixteen participants with a diagnosis of hemiparetic CP, with a median age of 6 years, were assessed pre and immediately post CIMT and at 6-month follow-up, using a picture–word match/mismatch discrimination task and standard neurobehavioral measures. Intervention effects were evident in improved performance on behavioral tests of sensory and motor function and the increased mean ERP amplitude of the N400 match/mismatch response on the side ipsilateral to the lesion. These effects were maintained 6 months after the intervention. No such changes were observed on the side contralateral to the lesion. This research suggests that ERPs can measure rehabilitation-induced changes in neural function in children with CP.

ERP Responses to Face Repetition During Passive Viewing: A Nonverbal Measure of Social Motivation in Children With Autism and Typical Development

This study examined whether individual differences in social motivation affect the extent of processing of social versus nonsocial information. Event-related potentials were recorded in 13 children with autism spectrum disorder and 11 typically developing children during passive viewing of unfamiliar faces and houses. One image in each category was presented repeatedly, the rest were shown once. Analyses indicated no group differences in the early perceptual responses. Only typical children evidenced larger P600 for the repeated faces. These results were replicated during a retest session. Individual differences in memory for the repeated faces correlated with standardized behavioral assessments of social skills.