Facial responsiveness to odours in normal and pervasively developmentally disordered children

Odor hedonic responses in children and young people with profound intellectual and multiple disabilities

Introduction

Odors are closely linked to emotions, play an important role in the well-being of individuals and can influence mood. Despite these crucial properties, the hedonic responses to odors of people with profound intellectual and multiple disabilities (PIMD) remain little explored.

Aim

This within-subjects study aims to examine whether children and young people with PIMD react in a differentiated way to odors evaluated as pleasant or unpleasant by neurotypical adults and, if so, with which behaviors. The influence of their global mood on their emotional responses to odors is also examined.

Method

Twenty children and young people (7-18 years old) with PIMD were exposed to four pairs of hedonically contrasted odors. A control stimulus was presented before each odorant. Five emotional responses, one physiological reaction (nausea reactions), and three responses reflecting approach toward or avoidance of the stimulus were recorded throughout the duration of the stimulus exposure. The participants' global mood status was measured before the start of the research with the French version of the Mood, Interest and Pleasure Questionnaire (Ross and Oliver, 2003).

Results

The results show that when exposed to pleasant odorants, participants kept their heads aligned with the odorant source longer, smiled longer, and produced more positive vocalizations. In contrast, unpleasant odorants elicit more pouts and grimaces. Nausea reactions occurred in the presence of unpleasant odorants. The hedonic responses were more marked during the second presentation of the stimuli. Participants with a higher MIPQ score showed significantly more emotional reactions to odors.

Conclusion

The results confirm the presence of olfactory preferences in participants with PIMD and the existence of a link between their mood, emotions and olfactory hedonic processing. They prompt the use of odors to support not only the cognitive development of this population, but also their mood and their emotional regulation abilities.

Neurobiology of sensory processing in autism spectrum disorder

Altered sensory processing and perception has been one of the characteristics of autism spectrum disorder (ASD). In this chapter, we review the neural underpinnings of sensory abnormalities of ASD by examining the literature on clinical, behavioral and neurobiological evidence that underlies the main patterns of sensory integration function and dysfunction. Furthermore, neural differences in anatomy, function and connectivity of different regions underlying sensory processing are also discussed. We conclude that sensory integration intervention is built on the premise of neuroplasticity to improve function and behavior for individuals with ASD.

Emotional responses to odors in children with high-functioning autism: autonomic arousal, facial behavior and self-report

Although emotional functioning is impaired in children with autism, it is unclear if this impairment is due to difficulties with facial expression, autonomic responsiveness, or the verbal description of emotional states. To shed light on this issue, we examined responses to pleasant and unpleasant odors in eight children (8-14 years) with high-functioning autism and 8 age-matched typically developing controls. Despite subtle differences in the facial actions of the children with autism, children in both groups had similar facial and autonomic emotional responses to the odors. However, children with autism were less likely than controls to report an emotional reaction to the odors that matched their facial expression, suggesting difficulties in the self report of emotional states.

Orofacial reactivity to the sight and smell of food stimuli. Evidence for anticipatory liking related to food reward cues in overweight children

Whether food liking may be a risk factor of overconsumption and overweight/obesity remains a controversial issue. So far, most studies used subjective reports to assess consummatory behavior, approaches that might overlook subtle or implicit hedonic changes to sensory properties of foods. Therefore, we used a cue-exposure approach by recording different measures of hedonic processes (orofacial reactivity, self-rated pleasantness, food preference) in 6-11 years old overweight (n=20) and normal-weight (n=20) children. Children were exposed to the smell and sight of high and low-energy density food stimuli and to non-food stimuli during pre- and post-prandial states. Their facial and verbal responses were videotaped and parent's reports of children's eating styles and appetitive traits were collected using the Children's Eating Behavior Questionnaire (CEBQ). Results showed that orofacial reactivity, as an objective measure of anticipatory liking, was more discriminative than self reports, with overweight children displaying more lip sucking than normal-weight children when exposed to high energy food pictures and to food odorants. Orofacial reactivity to food cues was also associated with BMI and children's eating styles (food responsiveness, emotional overeating, and desire to drink). Finally, overweight children classified more frequently non-food odorants as members of the food category during the pre-prandial state than during the post-prandial state, suggesting a possible influence of affective/motivational bias on odor categorization. Our findings suggest that orofacial responsiveness may be relevant to assess the sensitivity to energy-dense food reward cues in overweight children and for signaling, as an index of anticipatory liking, a potential risk for the development of overweight/obesity.

[Postoperative pain assessment in special patient groups: part II. Children with cognitive impairment]

Postoperative pain assessment in children with cognitive impairment poses major challenges to healthcare professionals.Children with moderate to severe cognitive impairment are generally unable to communicate effectively and to self-report the level of pain. Difficulties assessing pain have led to their exclusion from clinical trials and rendered them vulnerable to insufficient treatment of pain.The realization of pain is a particularly important step forward for a better care of children with cognitive impairment.Scales based on a child's own perception of pain and its severity play a limited role in this vulnerable population and pain assessment tools which rely on observing pain behavior are essential. The r-FLACC, which is reliable and valid, includes specific behavioral descriptors and can be used simply and effectively postoperatively in clinical practice. Our task has to be assessing pain as a routine procedure in cognitively impaired children as a keystone for an improved and successful pain management in this very sensitive patient population.

Cognitive facilitation following intentional odor exposure

This paper reviews evidence that, in addition to incidental olfactory pollutants, intentional odor delivery can impact cognitive operations both positively and negatively. Evidence for cognitive facilitation/interference is reviewed alongside four potential explanations for odor-induced effects. It is concluded that the pharmacological properties of odors can induce changes in cognition. However, these effects can be accentuated/attenuated by the shift in mood following odor exposure, expectancy of cognitive effects, and cues to behavior via the contextual association with the odor. It is proposed that greater consideration is required in the intentional utilization of odors within both industrial and private locations, since differential effects are observed for odors with positive hedonic qualities.

Subliminal fear priming potentiates negative facial reactions to food pictures in women with anorexia nervosa

BACKGROUND

To investigate hedonic reactivity and the influence of unconscious emotional processes on the low sensitivity to positive reinforcement of food in anorexia nervosa (AN).

METHOD

AN and healthy women were exposed to palatable food pictures just after a subliminal exposure to facial expressions (happy, disgust, fear and neutral faces), either while fasting or after a standardized meal (hunger versus satiety). Both implicit [facial electromyographic (EMG) activity from zygomatic and corrugator muscles, skin conductance, heart rate, and videotaped facial behavior] and explicit (self-reported pleasure and desire) measures of affective processes were recorded.

RESULTS

In contrast to healthy women, the AN patients did not display objective and subjective indices of pleasure to food pictures when they were in the hunger states. Pleasure to food cues (liking) was more affected than the desire to eat (wanting) in AN patients. Subliminal 'fear faces' increased corrugator muscle reactivity to food stimuli in fasting AN patients, as compared to controls.

CONCLUSIONS

The results suggest that unconscious fear cues increase the negative appraisal of alimentary stimuli in AN patients and thus contribute to decreased energy intake.

Autism: tactile perception and emotion

BACKGROUND

For many years, and especially since Waynbaum and Wallon, psychology and psychopathology have dealt with cognitive perception, but have had little to do with the affective qualities of perception. Our aim was to study the influence of the sensory environment on people with autism.

METHOD

Several experiments were carried out using different forms of tactile stimulation (passive and active subjects).

RESULTS

Our data showed specific responses in children with autism and intellectual disability. These children displayed a strong (positive) valence to the stimulation provided.

CONCLUSION

They were very attracted to the stimulation and were excited by it.

Facial and affective reactions to tastes and their modulation by sadness and joy

This study examined adults' affective and facial reactions to tastes which differ in quality and valence, and the impact of sadness and joy on these reactions. Thirty-six male and female subjects participated voluntarily. Subjects each tasted 6 ml of a sweet chocolate drink, a bitter quinine solution (0.0015 M) and a bitter-sweet soft drink. Following a baseline period, either joy or sadness was induced using film clips before the same taste stimuli were presented for a second time. Subjects rated the drinks' pleasantness and intensity of taste immediately after each stimulus presentation. Facial reactions were videotaped and analysed using the Facial Action Coding System (FACS [P. Ekman, W.V. Friesen, Facial Action Coding System: Manual. Palo Alto, CA: Consulting Psychologists Press; 1978., P. Ekman, W. Friesen, J. Hager, Facial Action Coding System. Salt Lake City, Utah: Research Nexus; 2002.]). The results strongly indicated that the tastes produced specific facial reactions that bear strong similarities to the facial reactivity patterns found in human newborns. The data also suggest that some adults' facial reactions serve additional communicative functions. Emotions modulated taste ratings, but not facial reactions to tastes. In particular, ratings of the sweet stimulus were modulated in congruence with emotion quality, such that joy increased and sadness decreased the pleasantness and sweetness of the sweet stimulus. No emotion-congruent modulation was found for the pleasantness and intensity ratings of the bitter or the bitter-sweet stimulus. This 'robustness' of bitter taste ratings may reflect a biologically meaningful mechanism.

Expression of Pain in Children With Autism

OBJECTIVES

Reduced pain sensitivity is widely reported to be a common feature of children with autism, yet this conclusion frequently has been based on anecdotal observations and questionable measures of pain. The aims of the study were to (1) characterize the behavioral response of children with autism experiencing a venepuncture using objective observational measures of pain and distress, (2) examine parents' assessments of pain behavior in children with and without autism, including comparison of the relationship of parental reports with behavioral measures, and (3) compare the behavioral reactions and parental assessments of children with autism with children without autism undergoing venepuncture.

METHODS

Pain reactions to the invasive procedure of venepuncture were videotaped, systematically described and compared in 21 children with autism (3-7 years old) and 22 nonimpaired children, the latter providing a chronological age and gender equivalent comparison group. Parents provided observer reports of pain, and facial activity was used as an objective behavioral measure of pain.

RESULTS

The children with autism displayed a significant facial pain reaction in response to the venepuncture procedure. There was a lack of concordance between parental reports of pain and observed pain responses for the children with autism. Behavioral responses of the children with autism were generally similar to the comparison group, except the substantial facial pain reactivity instigated by the venepuncture in the children with autism exceeded that displayed by the nonimpaired comparison children. Parent reports of pain severity did not differ between the autism and comparison groups. The degree of concordance between parental report and observed pain responses was consistently better for the comparison group.

DISCUSSION

The findings demonstrate that children with autism display a significant behavioral reaction in response to a painful stimulus, and these findings are in sharp contrast to the prevailing beliefs of pain insensitivity described in the literature to date. The findings also raise questions about the appropriateness of parental global report as an assessment tool for pain in children with autism.

Effects of pleasant and unpleasant ambient odors on human voice pitch

The perception of odors is well identified as having strong emotional correlates. It is also well known that the acoustic characteristics of the voice differ according to the emotional state. This study compared some acoustic features of the voice of 18 subjects reading the same text in pleasant (lavender) and unpleasant (pyridine) ambient odor conditions. The results revealed that the pitch of the voice was higher in the pleasant than in the unpleasant condition. These findings are consistent with the hypothesis of local and functional convergences of encoding vocal emotion and hedonic perception of odors.

Olfactory alliesthesia in human neonates: prandial state and stimulus familiarity modulate facial and autonomic responses to milk odors

This study examines the effects of a shift in the motivational state (from hunger to satiety) of human neonates on their behavioral and autonomic responsiveness to artificial and food-related odors as a function of stimulus familiarity. In Experiment 1, videotaped facial movements and autonomic (respiration rate: RR, heart rate: HR) responses to five olfactory stimuli (familiar regular formula, unfamiliar regular formula, protein hydrolysate formula, vanillin, control) are recorded in 3-day-old neonates (n = 14) during episodes of irregular sleep. The infants are tested on average 50 min. before and after bottle feeding. RR discriminates the odor stimuli from the control stimulus, indicating clear olfactory detection. Furthermore, neonates react with higher HR change only when exposed to their familiar formula milk during the postprandial condition. The measurement of facial movements with the Baby-Facial Action Coding System indicates that disgust and aversive actions are more often evoked by the odor of regular formulas (familiar or unfamiliar) than by the other olfactory stimuli during the postprandial condition. In Experiment 2, untrained adult observers, presented with the videotapes of the infants' facial responses to the odors, are able to decode differential hedonic signals from the sender faces as a function of the infants' motivational states. The present findings are in line with the concept of olfactory alliesthesia as defined in adults.

Correspondence of emotional self-rating with facial expression

Emotional processing abilities are difficult to measure psychometrically. Ultimately their quantification has to rely on 'subjective' judgment thereby leaving open the problem of response biases. Assessments of autonomic arousal similarly provide a mere unspecified measurement of a specific emotion. A standardized mood induction procedure capable of obtaining reliable happy and sad mood changes in healthy subjects was used to demonstrate the effectiveness of this procedure. We performed a two-part experiment using a rater-based analysis of facial expressions. This entailed analyzing the emotion portrayed in the faces. The faces of 24 healthy subjects were videotaped during the mood induction procedure of happiness and sadness, respectively. A group of 20 raters naive to the experimental task and conditions rated the facial expressions on six basic emotions. Results showed that ratings corresponded with the facial expressions, which were reflecting the mood of the task condition. Subjects' facial expressions together with self-ratings demonstrate the successful applicability of this standardized mood induction procedure for eliciting happy and sad mood.

Facial and autonomic responses to biological and artificial olfactory stimuli in human neonates: re-examining early hedonic discrimination of odors

Responses of awake and asleep 3-day-old human neonates were recorded to the presentation of artificial (vanillin, butyric acid, formula milks) and biological (breast milk, amniotic fluid) odorants matched on subjective intensity and trigeminal dimensions. The responses included behavioral (facial and oral movements) and autonomic (respiration, differential skin temperature) measures. The neonates reacted with significant facial and respiratory changes to low concentrations of olfactory stimuli during the various behavioral states. The analysis of olfacto-facial configurations revealed that behavioral markers of disgust (nose wrinkling, upper lip raising) discriminated between some odors judged as being pleasant and unpleasant by adult raters (vanillin vs. butyric acid). However, although some early predisposition to process the affective significance of stimuli may be suggested, no convincing evidence was obtained that neonates discriminated the hedonic valence of odors within the same perceptual space as adults. Finally, neonates evinced a differential pattern of respiratory responding to the presentation of milk odors according to the mode of feeding (breast vs. bottle feeding), suggesting that early olfactory discrimination may be mediated by stimuli with high ecological salience.