Enhanced visceromotor emotional reactivity in dyslexia and its relation to salience network connectivity

Elevated unanticipated acoustic startle reactivity in dyslexia

People with dyslexia, a neurodevelopmental disorder of reading, are highly attuned to the emotional world. Compared with their typically developing peers, children with dyslexia exhibit greater autonomic nervous system reactivity and facial behaviour to emotion- and empathy-inducing film clips. Affective symptoms, such as anxiety, are also more common in children with dyslexia than in those without. Here, we investigated whether the startle response, an automatic reaction that lies at the interface of emotion and reflex, is elevated in dyslexia. We measured facial behaviour, electrodermal reactivity (a sympathetic nervous system measure) and emotional experience in response to a 100 ms, 105 dB unanticipated acoustic startle task in 30 children with dyslexia and 20 comparison children without dyslexia (aged 7-13) who were matched on age, sex and nonverbal reasoning. Our results indicated that the children with dyslexia had greater total facial behaviour and electrodermal reactivity to the acoustic startle task than the children without dyslexia. Across the sample, greater electrodermal reactivity during the startle predicted greater parent-reported anxiety symptoms. These findings contribute to an emerging picture of heightened emotional reactivity in dyslexia and suggest accentuated sympathetic nervous system reactivity may contribute to the elevated anxiety that is often seen in this population.

The gift of dyslexia: what is the harm in it?

Dyslexia, characterized by word reading and spelling deficits, has historically been viewed through a medical model of disability. However, a countermovement has emerged, emphasizing the strengths and abilities of neurodiverse individuals, including those with dyslexia. The concept of neurodiversity, which was initially introduced to help inform understanding of a mild form of autism, has expanded to include dyslexia. The expansion has occurred alongside a similar portrayal of dyslexia as an advantage that comes with specific gifts, creating a positive stereotype. While intended to empower individuals with dyslexia, the translation of the concept of neurodiversity to dyslexia in this way can inadvertently stigmatize and isolate those who do not fit this positive stereotype of dyslexia. This review, following a perspective review article format, synthesizes existing literature on the purported gifts of dyslexia and the implications of both negative and positive stereotypes on the well-being of individuals with dyslexia. The findings of this review underscore the importance of dispelling myths about dyslexia and advocating against the use of stereotypes, both negative and positive, in portraying dyslexia. Doing so will help remove the harmful effects of stigmatization, stereotype threat, and the potential of a fixed mindset inherent to being stereotyped.

Towards a dynamic, comprehensive conceptualization of dyslexia

Here we build from the central strength of the existing definition of dyslexia-its emphasis on neurobiological origins-and proffer a set of seven core principles for a new, more comprehensive conceptualization of dyslexia. These principles derive from two major research directions: (1) the still evolving history of attempts to explain dyslexia, including in varied writing systems; and (2) the study of the reading brain circuit, its development, and its genetic and environmental influences. What emerges from connecting these two directions is a dynamic conceptualization of dyslexia that incorporates the extensive research on the heterogeneity of dyslexia and the interdependent contributions of multiple biological and socio-cultural risk and preventive factors. A new definition of dyslexia, therefore, needs to transcend both past unitary characterizations and past assumptions based largely on the English orthography. Such a conceptualization references the ways that different languages interact with the reading brain circuit to produce different sources of reading failure. Similarly, the characteristics and consequences of dyslexia that have been considered as secondary sequela (e.g., reduced reading comprehension, social-emotional issues) should be part of a more comprehensive narrative. Of critical importance, any definition of dyslexia should clarify persisting misconceptions that associate dyslexia with a lack of intelligence, potential to learn, or talents. Thus, the overall purpose of such a definition should serve as an instrument of knowledge and an enduring reason for pursuing growth in reading for the individual, the educator, and the public.

Elevated levels of mixed-hand preference in dyslexia: Meta-analyses of 68 studies

Since almost a hundred years, psychologists have investigated the link between hand preference and dyslexia. We present a meta-analysis to determine whether there is indeed an increase in atypical hand preference in dyslexia. We included studies used in two previous meta-analyses (Bishop, 1990; Eglinton & Annett, 1994) as well as studies identified through PubMed MEDLINE, PsycInfo, Google Scholar, and Web of Science up to August 2022. K = 68 studies (n = 4660 individuals with dyslexia; n = 40845 controls) were entered into three random effects meta-analyses using the odds ratio as the effect size (non-right-handers; left-handers; mixed-handers vs. total). Evidence of elevated levels of atypical hand preference in dyslexia emerged that were especially pronounced for mixed-hand preference (OR = 1.57), although this category was underdefined. Differences in (direction or degree) of hand skill or degree of hand preference could not be assessed as no pertinent studies were located. Our findings allow for robust conclusions only for a relationship of mixed-hand preference with dyslexia.

Reading anxiety modulates the functional connectivity of the reading-related network during adult reading

Researchers have studied cognitive and linguistic skills in predicting reading abilities, but the impact of affective factors such as anxiety on reading at the neurobiological level is not well understood. Here, we used functional magnetic resonance imaging to investigate the neural correlates of reading anxiety in adult readers performing a semantic judgment task. The results showed that reading anxiety was significantly correlated with response time but not with accuracy. Neurobiologically, functional connectivity strength rather than activation level of semantic-related areas significantly predicted reading anxiety. Activation of regions (i.e., the right putamen and right precentral gyrus) external to the semantic-related areas positively correlated with reading anxiety levels. These findings suggest that reading anxiety influences adult reading by modulating functional connections of semantic-related areas and brain activation of semantic-unrelated areas. This study provides insights into the neural mechanisms underlying reading anxiety experienced by adult readers.

Functional connectivity gradients of the cingulate cortex

Heterogeneity of the cingulate cortex is evident in multiple dimensions including anatomy, function, connectivity, and involvement in networks and diseases. Using the recently developed functional connectivity gradient approach and resting-state functional MRI data, we found three functional connectivity gradients that captured distinct dimensions of cingulate hierarchical organization. The principal gradient exhibited a radiating organization with transitions from the middle toward both anterior and posterior parts of the cingulate cortex and was related to canonical functional networks and corresponding behavioral domains. The second gradient showed an anterior-posterior axis across the cingulate cortex and had prominent geometric distance dependence. The third gradient displayed a marked differentiation of subgenual and caudal middle with other parts of the cingulate cortex and was associated with cortical morphology. Aside from providing an updated framework for understanding the multifaceted nature of cingulate heterogeneity, the observed hierarchical organization of the cingulate cortex may constitute a novel research agenda with potential applications in basic and clinical neuroscience.

Associations between dyslexia and children's mental health: Findings from a follow-up study in China

Dyslexia is a common learning difficulty that can lead to adverse health outcomes and socioeconomic difficulties. Evidence from longitudinal studies on the association between dyslexia and psychological symptoms in children is limited. Moreover, the psychological trends of children with dyslexia are unclear. In this study, we enrolled 2,056 students in Grades 2 to 5, including 61 dyslexic children, who participated in three mental health surveys and dyslexia screening. All the children were surveyed for symptoms of stress, anxiety and depression. We used generalized estimating equation models to estimate changes in psychological symptoms of children with dyslexia over time and the association between dyslexia and psychological symptoms. The results showed that dyslexia was associated with stress and depressive symptoms in children in both crude (β = 3.27, 95% confidence interval [CI] [1.89∼4.65], β=1.20, 95%CI: [0.45∼1.94], respectively) and adjusted models (β = 3.32, 95%CI: [1.87∼4.77], β=1.31, 95%CI: [0.52∼2.10], respectively). In addition, we found no significant differences in the emotional status of dyslexic children in either survey. Dyslexic children are at risk for mental health issues, and persistent emotional symptoms. Therefore, interventions regarding not only reading ability but also psychological conditions should be pursued.

Dynamic autonomic nervous system states arise during emotions and manifest in basal physiology

The outflow of the autonomic nervous system (ANS) is continuous and dynamic, but its functional organization is not well understood. Whether ANS patterns accompany emotions, or arise in basal physiology, remain unsettled questions in the field. Here, we searched for brief ANS patterns amidst continuous, multichannel physiological recordings in 45 healthy older adults. Participants completed an emotional reactivity task in which they viewed video clips that elicited a target emotion (awe, sadness, amusement, disgust, or nurturant love); each video clip was preceded by a pre-trial baseline period and followed by a post-trial recovery period. Participants also sat quietly for a separate 2-min resting period to assess basal physiology. Using principal components analysis and unsupervised clustering algorithms to reduce the second-by-second physiological data during the emotional reactivity task, we uncovered five ANS states. Each ANS state was characterized by a unique constellation of patterned physiological changes that differentiated among the trials of the emotional reactivity task. These ANS states emerged and dissipated over time, with each instance lasting several seconds on average. ANS states with similar structures were also detectable in the resting period but were intermittent and of smaller magnitude. Our results offer new insights into the functional organization of the ANS. By assembling short-lived, patterned changes, the ANS is equipped to generate a wide range of physiological states that accompany emotions and that contribute to the architecture of basal physiology.

Triple network activation causes tinnitus in patients with sudden sensorineural hearing loss: A model-based volume-entropy analysis

Tinnitus can be defined as the conscious perception of phantom sounds in the absence of corresponding external auditory signals. Tinnitus can develop in the setting of sudden sensorineural hearing loss (SSNHL), but the underlying mechanism is largely unknown. Using electroencephalography, we investigated differences in afferent node capacity between 15 SSNHL patients without tinnitus (NT) and 30 SSNHL patients with tinnitus (T). Where the T group showed increased afferent node capacity in regions constituting a "triple brain network" [default mode network (DMN), central executive network (CEN), and salience network (SN)], the NT group showed increased information flow in regions implicated in temporal auditory processing and noise-canceling pathways. Our results demonstrate that when all components of the triple network are activated due to sudden-onset auditory deprivation, tinnitus ensues. By contrast, auditory processing-associated and tinnitus-suppressing networks are highly activated in the NT group, to overcome the activation of the triple network and effectively suppress the generation of tinnitus.

Association between developmental dyslexia and anxiety/depressive symptoms among children in China: The chain mediating of time spent on homework and stress

BACKGROUND

The relationship between dyslexia and anxiety/depressive symptoms among children in China is unclear. Besides, the pathways to explain the risks are also undefined.

METHODS

3993 primary school students from grade 2 to 6 were recruited in this study. The Dyslexia Checklist for Chinese Children and the Pupil Rating Scale-Revised Screening for Learning Disabilities were used to filter the dyslexic children. The Chinese perceived stress scale, the Screen for Child Anxiety Related Emotional Disorders, and the Children's Depression Inventory-Short Form were used separately to assess stress, anxiety symptoms, and depressive symptoms of the children. Time spent on homework was obtained by asking their parents: "How long does it take the children to complete the homework every day?". The chain mediation models were examined using SPSS PROCESS macro 3.3 software.

RESULTS

Dyslexic children spend more time on homework (2.61±1.15), and have higher scores for depression (4.75±3.60) and stress (26.55±7.40) compared to normal children (1.87±0.77, 3.25±3.32, and 23.20±8.43, respectively). The differences are statistically significant (all P<0.01). There is no direct association between dyslexia and anxiety symptoms, while dyslexia has a direct link with depressive symptoms. Dyslexia could affect anxiety/depressive symptoms via the independent mediating effect of stress and the chain mediating effect of time spent on homework and stress. The total indirect effect is 0.21 and 0.25, respectively.

LIMITATIONS

The data used in our study is self-reported and this is a cross-sectional study.

CONCLUSIONS

Time spent on homework and stress could mediate the association between dyslexia and anxiety/depressive symptoms.

Children with developmental dyslexia show elevated parasympathetic nervous system activity at rest and greater cardiac deceleration during an empathy task

Reading difficulties are the hallmark feature of dyslexia, but less is known about other areas of functioning. Previously, we found children with dyslexia exhibited heightened emotional reactivity, which correlated with better social skills. Whether emotional differences in dyslexia extend to the parasympathetic nervous system-an autonomic branch critical for attention, social engagement, and empathy-is unknown. Here, we measured autonomic nervous system activity in 24 children with dyslexia and 24 children without dyslexia, aged 7 - 12, at rest and during a film-based empathy task. At rest, children with dyslexia had higher respiratory sinus arrhythmia (RSA) than those without dyslexia. Cardiac deceleration during the empathy task was greater in dyslexia and correlated with higher resting RSA across the sample. Children with dyslexia produced more facial expressions of concentration during film-viewing, suggesting greater engagement. These results suggest elevated resting parasympathetic activity and accentuated autonomic and behavioral responding to others' emotions in dyslexia.