Vocal emotion recognition in attention-deficit hyperactivity disorder: a meta-analysis.

There is debate within the literature as to whether emotion dysregulation (ED) in Attention-Deficit Hyperactivity Disorder (ADHD) reflects deviant attentional mechanisms or atypical perceptual emotion processing. Previous reviews have reliably examined the nature of facial, but not vocal, emotion recognition accuracy in ADHD. The present meta-analysis quantified vocal emotion recognition (VER) accuracy scores in ADHD and controls using robust variance estimation, gathered from 21 published and unpublished papers. Additional moderator analyses were carried out to determine whether the nature of VER accuracy in ADHD varied depending on emotion type. Findings revealed a medium effect size for the presence of VER deficits in ADHD, and moderator analyses showed VER accuracy in ADHD did not differ due to emotion type. These results support the theories which implicate the role of attentional mechanisms in driving VER deficits in ADHD. However, there is insufficient data within the behavioural VER literature to support the presence of emotion processing atypicalities in ADHD. Future neuro-imaging research could explore the interaction between attention and emotion processing in ADHD, taking into consideration ADHD subtypes and comorbidities.

Development of the neural processing of vocal emotion during the first year of life.

Human infants are "wired" to respond to social information, an important capacity for survival. The ability to discriminate vocal emotion in others is likely to play a key role in successful social interactions with caregivers, which facilitate the rapid social-communicative development that infants typically undergo in the latter half of their first year. Infants have voice-sensitive brain regions that have been shown previously to be responsive to emotional prosody by 7 months. This study aimed to investigate the developmental trajectory of vocal emotion processing in temporal regions using functional near-infrared spectroscopy (fNIRS) to measure brain sensitivity to angry, happy, and neutral vocalizations in the same infant at 6, 9, and 12 months. We found significant and increasing temporal cortical activation in response to vocal emotional stimuli over the three time points, suggesting consistent enhanced responses for happy compared to angry vocalizations, and vocal anger sensitivity is developing incrementally. The findings suggest that the neural processing of angry and happy prosody may follow distinct developmental pathways and is gradually "tuned" to become specialized between 6 and 12 months. This first longitudinal study of vocal emotion brain processing between 6 and 12 months highlights the need for more research to understand what drives typical and atypical social cognitive development across infancy and for follow-up into the second year.

The reinforcing value of delay escape in attention deficit/hyperactivity disorder: An electrophysiological study.

The delay aversion hypothesis argues that the tendency for impulsive choice (preference for smaller sooner over larger later rewards) is motivated by the escape of negative affective states associated with delay. This model predicts that individuals with ADHD find the imposition of delay before an outcome or event especially aversive and its escape reinforcing. Consistent with this, fMRI studies show that ADHD is associated with amygdala hyper-sensitivity to cues of delay. However, evidence that delay escape is reinforcing is lacking. Here we extend fMRI research by using electrophysiological methods to study the reinforcing properties of delay-escape in ADHD. Thirty controls and 25 adolescents with ADHD aged 10-15 years performed the Escape Delay Incentive (EDI) task- in which pre-target cues indicated three conditions: i) CERTAIN DELAY: delay would follow a response irrespective of response speed ii) CONDITIONAL DELAY: delay would only follow if the response was too slow and iii) NO DELAY: delay would follow the response whatever the speed. We focused on the Contingent Negative Variation (CNV), a cue-evoked marker of motivated response preparation, across two time windows (CNV1 and CNV2). We took measures of parent, teacher and self-rated ADHD symptoms, task performance (RT) and self-rated delay aversion. We isolated CNV components and compared these between ADHD and controls. Adolescents with ADHD displayed a larger CNV2 to the CONDITIONAL DELAY than the CERTAIN DELAY cues compared to controls. However, this effect was not mirrored at the performance level and was unrelated to self-reported delay aversion. Our study provides the first ERP evidence that delay escape differentially reinforcers neural activation of attention preparation in ADHD cases. Future studies should examine the impact of varying cognitive load on task EDI performance.

Is infant neural sensitivity to vocal emotion associated with mother-infant relational experience?

An early understanding of others' vocal emotions provides infants with a distinct advantage for eliciting appropriate care from caregivers and for navigating their social world. Consistent with this notion, an emerging literature suggests that a temporal cortical response to the prosody of emotional speech is observable in the first year of life. Furthermore, neural specialisation to vocal emotion in infancy may vary according to early experience. Neural sensitivity to emotional non-speech vocalisations was investigated in 29 six-month-old infants using near-infrared spectroscopy (fNIRS). Both angry and happy vocalisations evoked increased activation in the temporal cortices (relative to neutral and angry vocalisations respectively), and the strength of the angry minus neutral effect was positively associated with the degree of directiveness in the mothers' play interactions with their infant. This first fNIRS study of infant vocal emotion processing implicates bilateral temporal mechanisms similar to those found in adults and suggests that infants who experience more directive caregiving or social play may more strongly or preferentially process vocal anger by six months of age.

The development of cross-cultural recognition of vocal emotion during childhood and adolescence.

Humans have an innate set of emotions recognised universally. However, emotion recognition also depends on socio-cultural rules. Although adults recognise vocal emotions universally, they identify emotions more accurately in their native language. We examined developmental trajectories of universal vocal emotion recognition in children. Eighty native English speakers completed a vocal emotion recognition task in their native language (English) and foreign languages (Spanish, Chinese, and Arabic) expressing anger, happiness, sadness, fear, and neutrality. Emotion recognition was compared across 8-to-10, 11-to-13-year-olds, and adults. Measures of behavioural and emotional problems were also taken. Results showed that although emotion recognition was above chance for all languages, native English speaking children were more accurate in recognising vocal emotions in their native language. There was a larger improvement in recognising vocal emotion from the native language during adolescence. Vocal anger recognition did not improve with age for the non-native languages. This is the first study to demonstrate universality of vocal emotion recognition in children whilst supporting an "in-group advantage" for more accurate recognition in the native language. Findings highlight the role of experience in emotion recognition, have implications for child development in modern multicultural societies and address important theoretical questions about the nature of emotions.

The Moderating Effect of Self-Reported State and Trait Anxiety on the Late Positive Potential to Emotional Faces in 6-11-Year-Old Children.

Introduction: The emergence of anxiety during childhood is accompanied by the development of attentional biases to threat. However, the neural mechanisms underlying these biases are poorly understood. In addition, previous research has not examined whether state and trait anxiety are independently associated with threat-related biases. Methods: We compared ERP waveforms during the processing of emotional faces in a population sample of 58 6-11-year-olds who completed self-reported measures of trait and state anxiety and depression. Results: The results showed that the P1 was larger to angry than neutral faces in the left hemisphere, though early components (P1, N170) were not strongly associated with child anxiety or depression. In contrast, Late Positive Potential (LPP) amplitudes to angry (vs. neutral) faces were significantly and positively associated with symptoms of anxiety/depression. In addition, the difference between LPPs for angry (vs. neutral) faces was independently associated with state and trait anxiety symptoms. Discussion: The results showed that neural responses to facial emotion in children with elevated symptoms of anxiety and depression were most evident at later processing stages characterized as evaluative and effortful. The findings support cognitive models of threat perception in anxiety and indicate that trait elements of anxiety and more transitory fluctuations in anxious affect are important in understanding individual variation in the neural response to threat in late childhood.

An electrophysiological investigation of reinforcement effects in attention deficit/hyperactivity disorder: Dissociating cue sensitivity from down-stream effects on target engagement and performance.

OBJECTIVE: Neural hypo-sensitivity to cues predicting positive reinforcement has been observed in ADHD using the Monetary Incentive Delay (MID) task. Here we report the first study using an electrophysiological analogue of this task to distinguish between (i) cue related anticipation of reinforcement and downstream effects on (ii) target engagement and (iii) performance in a clinical sample of adolescents with ADHD and controls. METHODS: Thirty-one controls and 32 adolescents with ADHD aged 10-16 years performed the electrophysiological (e)-MID task - in which preparatory cues signal whether a response to an upcoming target will be reinforced or not - under three conditions; positive reinforcement, negative reinforcement (response cost) and no consequence (neutral). We extracted values for both cue-related potentials known to be, both, associated with response preparation and modulated by reinforcement (Cue P3 and Cue CNV) and target-related potentials (target P3) and compared these between ADHD and controls. RESULTS: ADHD and controls did not differ on cue-related components on neutral trials. Against expectation, adolescents with ADHD displayed Cue P3 and Cue CNV reinforcement-related enhancement (versus neutral trials) compared to controls. ADHD individuals displayed smaller target P3 amplitudes and slower and more variable performance - but effects were not modulated by reinforcement contingencies. When age, IQ and conduct problems were controlled effects were marginally significant but the pattern of results did not change. DISCUSSION: ADHD was associated with hypersensitivity to positive (and marginally negative) reinforcement reflected on components often thought to be associated with response preparation - however these did not translate into improved attention to targets. In the case of ADHD, upregulated CNV may be a specific marker of hyper-arousal rather than an enhancement of anticipatory attention to upcoming targets. Future studies should examine the effects of age, IQ and conduct problems on reinforcement sensitivity in ADHD.

Event-Related Potentials and Emotion Processing in Child Psychopathology.

In recent years there has been increasing interest in the neural mechanisms underlying altered emotional processes in children and adolescents with psychopathology. This review provides a brief overview of the most up-to-date findings in the field of event-related potentials (ERPs) to facial and vocal emotional expressions in the most common child psychopathological conditions. In regards to externalizing behavior (i.e., ADHD, CD), ERP studies show enhanced early components to anger, reflecting enhanced sensory processing, followed by reductions in later components to anger, reflecting reduced cognitive-evaluative processing. In regards to internalizing behavior, research supports models of increased processing of threat stimuli especially at later more elaborate and effortful stages. Finally, in autism spectrum disorders abnormalities have been observed at early visual-perceptual stages of processing. An affective neuroscience framework for understanding child psychopathology can be valuable in elucidating underlying mechanisms and inform preventive intervention.

Atypical neural responses to vocal anger in attention-deficit/hyperactivity disorder.

BACKGROUND: Deficits in facial emotion processing, reported in attention-deficit/hyperactivity disorder (ADHD), have been linked to both early perceptual and later attentional components of event-related potentials (ERPs). However, the neural underpinnings of vocal emotion processing deficits in ADHD have yet to be characterised. Here, we report the first ERP study of vocal affective prosody processing in ADHD. METHODS: Event-related potentials of 6-11-year-old children with ADHD (n = 25) and typically developing controls (n = 25) were recorded as they completed a task measuring recognition of vocal prosodic stimuli (angry, happy and neutral). Audiometric assessments were conducted to screen for hearing impairments. RESULTS: Children with ADHD were less accurate than controls at recognising vocal anger. Relative to controls, they displayed enhanced N100 and attenuated P300 components to vocal anger. The P300 effect was reduced, but remained significant, after controlling for N100 effects by rebaselining. Only the N100 effect was significant when children with ADHD and comorbid conduct disorder (n = 10) were excluded. CONCLUSION: This study provides the first evidence linking ADHD to atypical neural activity during the early perceptual stages of vocal anger processing. These effects may reflect preattentive hyper-vigilance to vocal anger in ADHD.

The development of emotion recognition from facial expressions and non-linguistic vocalizations during childhood.

Sensitivity to facial and vocal emotion is fundamental to children's social competence. Previous research has focused on children's facial emotion recognition, and few studies have investigated non-linguistic vocal emotion processing in childhood. We compared facial and vocal emotion recognition and processing biases in 4- to 11-year-olds and adults. Eighty-eight 4- to 11-year-olds and 21 adults participated. Participants viewed/listened to faces and voices (angry, happy, and sad) at three intensity levels (50%, 75%, and 100%). Non-linguistic tones were used. For each modality, participants completed an emotion identification task. Accuracy and bias for each emotion and modality were compared across 4- to 5-, 6- to 9- and 10- to 11-year-olds and adults. The results showed that children's emotion recognition improved with age; preschoolers were less accurate than other groups. Facial emotion recognition reached adult levels by 11 years, whereas vocal emotion recognition continued to develop in late childhood. Response bias decreased with age. For both modalities, sadness recognition was delayed across development relative to anger and happiness. The results demonstrate that developmental trajectories of emotion processing differ as a function of emotion type and stimulus modality. In addition, vocal emotion processing showed a more protracted developmental trajectory, compared to facial emotion processing. The results have important implications for programmes aiming to improve children's socio-emotional competence.

Emotion-recognition abilities and behavior problem dimensions in preschoolers: evidence for a specific role for childhood hyperactivity.

Facial emotion-recognition difficulties have been reported in school-aged children with behavior problems; little is known, however, about either this association in preschool children or with regard to vocal emotion recognition. The current study explored the association between facial and vocal emotion recognition and behavior problems in a sample of 3 to 6-year-old children. A sample of 57 children enriched for risk of behavior problems (41 were recruited from the general population while 16 had been referred for behavior problems to local clinics) were each presented with a series of vocal and facial stimuli expressing different emotions (i.e., angry, happy, and sad) of low and high intensity. Parents rated children's externalizing and internalizing behavior problems. Vocal and facial emotion recognition accuracy was negatively correlated with externalizing but not internalizing behavior problems independent of emotion type. The effects with the externalizing domain were independently associated with hyperactivity rather than conduct problems. The results highlight the importance of using vocal as well as facial stimuli when studying the relationship between emotion-recognition and behavior problems. Future studies should test the hypothesis that difficulties in responding to adult instructions and commands seen in children with attention deficit/hyperactivity disorder (ADHD) may be due to deficits in the processing of vocal emotions.

An electrophysiological monetary incentive delay (e-MID) task: a way to decompose the different components of neural response to positive and negative monetary reinforcement.

BACKGROUND: The ability to anticipate and then secure future rewards and avoid future punishments by responding effectively to environmental demands is at the core of successful decision making. Disruptions to these processes have been shown to be implicated in a number of psychiatric conditions. In the current paper we use the electrophysiological monetary incentive delay task (e-MID) to decompose the neural response to (i) reinforcement anticipation, (ii) reinforcement-contingent target processing and (iii) reinforcement-related feedback. METHODS: Thirty-eight adolescents and young adults performed an ERP-based analogue of the monetary incentive delay task. ERP components previously associated with motivationally salient cue (cue-P3 and contingent negative variation, CNV), target (P3) and feedback (success vs. failure; feedback-related negativity; FRN and the late positive potential; LPP) stimuli were examined. RESULTS: Response times were shorter and less variable in the monetary gain and loss conditions. Distinctive ERP components were observed for each phase of reinforcement processing. First, cue-P3 was enhanced to monetary gain cues. Predicted alterations in cue-P3 following monetary loss cues and the CNV following cues of either monetary loss or gain were not observed. Target P3 was enhanced in both incentive conditions. The FRN was greater following monetary loss feedback. LPP amplitude was enhanced following feedback denoting monetary gain and the avoidance of monetary loss. CONCLUSION: Although behaviourally the effects of monetary loss and gain were similar, the e-MID task differentiated neural processing in terms of anticipation and feedback-related brain potentials. The e-MID task and the results of the current study provide a valuable complement to fMRI-based approaches to studying normal and abnormal brain correlates of reinforcement processing.

Isolating N400 as neural marker of vocal anger processing in 6-11-year old children.

INTRODUCTION: Vocal anger is a salient social signal serving adaptive functions in typical child development. Despite recent advances in the developmental neuroscience of emotion processing with regard to visual stimuli, little remains known about the neural correlates of vocal anger processing in childhood. This study represents the first attempt to isolate a neural marker of vocal anger processing in children using electrophysiological methods. METHODS: We compared ERP wave forms during the processing of non-word emotional vocal stimuli in a population sample of 55 6-11-year-old typically developing children. Children listened to three types of stimuli expressing angry, happy, and neutral prosody and completed an emotion identification task with three response options (angry, happy and neutral/'ok'). RESULTS: A distinctive N400 component which was modulated by emotional content of vocal stimulus was observed in children over parietal and occipital scalp regions-amplitudes were significantly attenuated to angry compared to happy and neutral voices. DISCUSSION: Findings of the present study regarding the N400 are compatible with adult studies showing reduced N400 amplitudes to negative compared to neutral emotional stimuli. Implications for studies of the neural basis of vocal anger processing in children are discussed.

Electrophysiological markers of the motivational salience of delay imposition and escape.

BACKGROUND: The ubiquitous tendency to choose immediate over delayed rewards can, in extremis, lead to maladaptive preferences for smaller sooner over larger later rewards (i.e., impulsive choice) in certain pathological groups. The delay aversion hypothesis provides one possible account of impulsive choice and argues that this tendency is motivated by the avoidance of the negative affective states associated with delay imposed prior to the delivery of a large reward. This model also predicts that on non-choice tasks individuals will be motivated to work harder and more efficiently, when given the opportunity to avoid delay. In the current paper we studied the neural markers of the motivational salience of the imposition and escape from delay using a simple reaction time task under two conditions: First where fast responses were expected to lead to delay escape and second where delay was inescapable. METHODS: Forty participants performed the Escape Delay Incentive (EDI) task during which they were asked to respond as quickly as they could to a target stimulus. The EDI task included two conditions: first, a Delay Escape condition where fast responses led to the avoidance of delay and a Delay No-Escape condition in which a delay was presented on every trial irrespective of response speed. EEG was recorded from 66 equidistant electrode sites across the scalp. The neural response in these two conditions was compared in terms of contingent negative variation (CNV; preparation of motivated responses) and late positive potential, LPP; evaluation of performance feedback). RESULTS: As predicted individuals responded more quickly and showed enhanced CNV amplitude to Delay Escape compared with Delay No-Escape trials. Enhanced LPP amplitude was also observed when participants were not able to avoid the delay in the Delay Escape condition. ADHD symptoms were associated with larger CNV differences between Delay Escape and Delay No-Escape conditions. An association between ADHD symptoms and the LPP in the Delay Escape condition did not reach significance. CONCLUSION: The results of the current study suggest that delay escape is a potent reinforcer at both behavioural and neural levels. Future research should extend this analysis to clinical samples using a broader range of delays and across imaging modalities.