Neuro-physiological correlates of sluggish cognitive tempo (SCT) symptoms in school-aged children

Bibliometric Trends and Thematic Areas in Research on Cognitive Disengagement Syndrome in Children: A Comprehensive Review

This study aims to explore trends and principal research areas in the literature on Cognitive Disengagement Syndrome (CDS) in children aged 0-17 from a macro perspective. A total of 236 studies, selected based on inclusion and exclusion criteria from the Web of Science and Scopus databases, formed the data source for this research. We conducted a bibliometric analysis to examine the growth of CDS literature and to identify the most productive countries, relevant journals and publications, and trending topics. Additionally, through content analysis, we identified general research themes, sample trends, and methodologies used in these studies. Our findings reveal that the relatively new field of CDS research is expanding. Our thematic analysis shows that the literature on CDS covers a broad spectrum of research topics, addressing various facets of the syndrome and identifying current research themes. The existing studies highlight the complex nature of CDS and its diverse cognitive, psychological, and neurological impacts. Our results also suggest that while research is more prevalent in certain age groups, there is a need to encompass a wider demographic range, considering CDS's potential impact across different life stages. This bibliometric analysis offers a comprehensive review of the current knowledge in the CDS field, providing a valuable resource for researchers. Our analyses and findings can guide future research in this area and suggest approaches for broader study frameworks. It is anticipated that ongoing and future research in the CDS field will incorporate these insights to more effectively address the syndrome's varied aspects and consequences.

The prevalence of SCT in China, its comorbidity with ADHD and its association with life events and parental-rearing behaviors

Although sluggish cognitive tempo (SCT) symptoms are often observed in children with attention deficit hyperactivity disorder (ADHD), an increasing number of studies have highlighted its uniqueness. Nevertheless, no national survey on SCT among children and adolescents has been conducted in China. Hence, this research aims to study SCT in China and to evaluate the differences between SCT and ADHD symptoms by comparing their risk factors in terms of life events (LE) and parental rearing behaviors (PRB). This cross-sectional study used data from a survey on 71,929 children and adolescents in 5 province-level regions in China to study the incidence and demographic information of SCT in the Chinese population. Subsequently, the study investigated the comorbidity of ADHD and SCT, and conducted three logistic regressions on the LE and PRB scores to predict whether participants develop symptoms of ADHD or SCT, or neither symptom. 6658 participants were allocated into the SCT group, and the weighted point prevalence of SCT was 9.78%. 36.34% of participants with ADHD (n = 676) were found to demonstrate SCT symptoms, whereas no statistically significant difference was observed in its comorbidity to the three ADHD subtypes (χ2 = 1.668, p > 0.05, Δ = 2). The regression results on the presence or absence of ADHD revealed paternal excessive-interference and rejection, and maternal favoring were associated with ADHD diagnosis, whereas paternal punishment and favoring and maternal emotional warmth was related to the absence of ADHD symptoms. Academic stress and maternal excessive-interference were associated with SCT symptoms, and maternal emotional warmth associated with SCT absence. Concerning the presence of ADHD-only or SCT-only symptoms, LE adaptation was found to relate to SCT-only symptoms, while PRB paternal rejection and maternal favoring were associated with ADHD-only symptoms. While evidencing the high prevalence of SCT in China, our findings supported that although ADHD and SCT were highly comorbid, they may be considered two independent disorders with different risk factors. Specifically, participants with SCT symptoms are more vulnerable to stress from LE and tend to face more maladjustment than ADHD and normally-developing participants, and maternal rearing behaviours are the key factors to SCT symptoms. SCT brings global challenges in its diagnosis and treatment, and the challenge is more severe in a mentally stressful environment. Therefore, stress management and SCT etiology studies are recommended.

Physical and Extracurricular Activity in Adolescents With and Without ADHD: Examining Group Differences and the Role of Cognitive Disengagement Syndrome Symptoms

OBJECTIVE

This study examined extracurricular and physical activity related to ADHD (diagnosis and symptoms) and cognitive disengagement syndrome (CDS) symptoms.

METHODS

Participants were 302 adolescents (ages 12-14) with and without ADHD and primary caregivers. ADHD diagnosis was determined with parent interview. Questionnaires provided information on parent-reported demographic characteristics, ADHD symptoms, and extracurricular activity involvement; and adolescent-reported ADHD and CDS symptoms and indices of physical activity.

RESULTS

Although ADHD diagnosis and symptom dimensions were correlated with less extracurricular and physical activity involvement, CDS symptoms were most often independently associated with these outcomes. Females and adolescents from lower income homes also often had less involvement in extracurricular and physical activity.

CONCLUSIONS

Findings point to the need for more research in this area, careful assessment of risk factors (i.e., CDS symptoms, economic burden), and interventions that address inactivity in adolescents with ADHD, including those that address inequity related to income and sex.

Report of a Work Group on Sluggish Cognitive Tempo: Key Research Directions and a Consensus Change in Terminology to Cognitive Disengagement Syndrome

OBJECTIVE

The aim of this work was 2-fold: (1) to evaluate current knowledge and identify key directions in the study of sluggish cognitive tempo (SCT); and (2) to arrive at a consensus change in terminology for the construct that reflects the current science and may be more acceptable to researchers, clinicians, caregivers, and patients.

METHOD

An international Work Group was convened that, in early 2021, compiled an online archive of all research studies on SCT and summarized the current state of knowledge, noted methodological issues, and highlighted future directions, and met virtually on 10 occasions in 2021 to discuss these topics and terminology.

RESULTS

Major progress has been made over the last decade in advancing our understanding of SCT across the following domains of inquiry: construct measurement and stability; genetic, environmental, pathophysiologic, and neuropsychological correlates; comorbid conditions; functional impairments; and psychosocial and medication interventions. Findings across these domains are summarized, and potential avenues to pursue in the next generation of SCT-related research are proposed. Following repeated discussions on terminology, the Work Group selected "cognitive disengagement syndrome" (CDS) to replace "SCT" as the name for this construct. This term was deemed to best satisfy considerations that should apply when selecting terms for a condition or syndrome, as it does not overlap with established terms for other constructs, is not offensive, and reflects the current state of the science.

CONCLUSION

It is evident that CDS (SCT) has reached the threshold of recognition as a distinct syndrome. Much work remains to further clarify its nature (eg, transdiagnostic factor, separate disorder, diagnostic specifier), etiologies, demographic factors, relations to other psychopathologies, and linkages to specific domains of functional impairment. Investigators are needed with interests and expertise spanning basic, clinical, and translational research to advance our understanding and to improve the lives of individuals with this unique syndrome.

Abnormal physiological responses toward sensory stimulus are related to the attention deficits in children with sluggish cognitive tempo

Previous studies have found that sluggish cognitive tempo (SCT) is often associated with difficulties in real-life functioning, such as social problems, emotional difficulties, and academic learning difficulties. However, the underlying mechanisms contributing to the SCT symptoms and its associated real-life difficulties have still not been clearly understood. A previous study has found that SCT symptoms were associated with hypoarousal and hyperarousal toward the sensory stimulus. However, it is still unclear whether such abnormal arousal regulation is related to sustained attention difficulties that have been found to be related to social difficulties and withdrawn behavior in children with SCT. In this study, arousal regulation deficit in SCT is examined by the physiological responses quantified by HRV and EEG in the sensory challenge paradigm. This study aimed to establish a linkage between arousal regulation reflected by HRV and EEG and attention difficulties in children with SCT. The results of this study showed that higher theta power in the auditory stimulation condition than in the resting condition was associated with higher omission errors in sustained attention tasks in the SCT group. It was also found that higher parasympathetic activities during sensory stimulation conditions were associated with higher commission errors in the SCT group. These results reflected that hypersensitivity toward stressful sensitivity toward a stressful sensory stimulus is associated with attention difficulties in children with SCT. This further supported the notion that SCT should be conceptualized as a condition characterized by multiple deficits in different biological systems, such as the cognitive system, the negative valence system, and the arousal regulatory system.

Sluggish Cognitive Tempo in Pediatric Sickle Cell Disease

Background

Sickle cell disease (SCD) imparts risk for a range of neurodevelopmental and neurocognitive disorders. Sluggish cognitive tempo (SCT) is a distinct syndrome that often co-occurs with attention-deficit/hyperactivity disorder (ADHD) but has not been described in SCD. We investigated the reliability and validity of a SCT measure in SCD and examined associations with biopsychosocial risk factors and functional outcomes.

Materials and Methods

Caregivers (n = 85) of children with SCD ages 7-16 reported on socio-demographics and the Kiddie-Sluggish Cognitive Tempo (K-SCT) measure, Behavior Rating Inventory of Executive Function, and Conners 3. Disease-related characteristics were extracted from health records.

Results

The K-SCT demonstrated excellent internal consistency (α = 0.92) and test-retest reliability (r = 0.82, p < 0.001). K-SCT scores were correlated with ADHD-Inattention (r = 0.64, p < 0.001) and ADHD-Hyperactive/Impulsive (r = 0.46, p < 0.001) scores, as well as functional outcomes, including learning problems (r = 0.69, p < 0.001). In multivariate analyses controlling for ADHD symptoms, SCT accounted for unique variance in learning (b = 9.67, p < 0.01) and executive functioning (b = 5.93, p < 0.01). Nearly all participants (93%) with elevated levels of co-occurring SCT and ADHD-Inattention symptoms had significant learning problems.

Conclusion

The K-SCT is a reliable and valid measure of SCT in SCD. SCT symptoms are associated with learning difficulties even after controlling for ADHD symptoms. Further research is needed to understand the biopsychosocial factors that lead to SCT symptoms in SCD and examine long-term implications of SCT.

Relationship between sluggish cognitive tempo, IQ and academic achievement test scores, and academic impairment in autism, ADHD, and elementary school samples

Sluggish cognitive tempo (SCT) is of renewed interest. The relationship between SCT, IQ and achievement scores, and academic impairment ratings was investigated in 218 students with autism and 676 with ADHD (6-16 years) and 549 elementary school students (IQ ≥ 80). Mothers rated their children on the Pediatric Behavior Scale. Children in the autism/ADHD sample were also rated by teachers. Correlations between SCT and IQ and achievement scores (Verbal Comprehension, Perceptual Reasoning, Working Memory, Processing Speed, reading, math, and written expression) were all negative and were nonsignificant in the total autism/ADHD and elementary school samples, except for small correlations with Processing Speed and a timed math test. In contrast, mother and teacher SCT ratings were significantly related to mother and teacher academic and cognitive impairment ratings. SCT was not a significant predictor of achievement scores or academic impairment ratings in regression analysis. The strongest predictor of achievement test scores was IQ, and the strongest predictors of academic impairment were mother and teacher cognitive impairment ratings. Teacher inattention ratings predicted teacher academic impairment ratings in autism/ADHD and mother inattention ratings predicted mother academic impairment ratings in elementary school children. Therefore, inattention was more predictive of academic functioning than was SCT. Research shows a weak link between SCT and processing speed (contrary to what is implied by the term sluggish cognitive tempo), and other neuropsychological test scores are not consistently associated with SCT. It remains to be determined if neuropsychological tests can be developed to measure and further our understanding of SCT.

Systematic Review: Assessment of Sluggish Cognitive Tempo Over the Past Decade

OBJECTIVE

To conduct a systematic review of the measures designed to assess sluggish cognitive tempo (SCT) since the first SCT scale using careful test-construction procedures was published in 2009.

METHOD

MEDLINE (PubMed), Embase, PsychINFO, and Web of Science databases were searched from September 2009 through December 2019. Articles reporting on reliability (internal consistency, test-retest, and interrater reliability), structural validity (an aspect of construct validity focused on items' convergent and discriminant validity), concurrent and longitudinal external validity, invariance, or intervention/experimental findings were included.

RESULTS

Full criteria for data extraction and inclusion were met by 76 studies. Nine measures for assessing SCT were identified (7 assessing parent report, teacher report, and/or self-report in children and 2 assessing self-report and/or collateral informant report in adults). Each measure demonstrated acceptable to excellent reliability. All or at least the majority of SCT items on each measure also had structural validity (high loadings on an SCT factor and low loadings on an attention-deficit/hyperactivity disorder [ADHD] inattention factor). Studies have supported the invariance of SCT across sex and time, and there is initial evidence of invariance across informants, youths with ADHD and youths without ADHD, and ADHD presentations. The Child and Adolescent Behavior Inventory (CABI), Child Concentration Inventory, Second Edition (CCI-2), and Barkley Adult ADHD Rating Scale-IV (BAARS-IV) have particularly strong support for assessing parent/teacher-reported, youth self-reported, and adult self-reported SCT, respectively.

CONCLUSION

The SCT measures included in this review share numerous positive properties, have promising psychometric support, and have proven useful for examining the external correlates of SCT across the life span. Although substantial progress has been made over the last decade, work remains to be done to further improve the assessment of SCT and key directions for future research are provided.

Sluggish Cognitive Tempo and Neuropsychological Functioning

Sluggish cognitive tempo (SCT) is marked by impairments across social, emotional, and academic functioning, but few studies have examined the association between SCT and neuropsychological functioning. The present study examined the associations between SCT and measures of processing speed, executive function, attention, and reaction time. From a larger sample of 8,238 children and adolescents, a subsample of 928 children were overselected for symptoms of SCT or attention-deficit/hyperactivity disorder (ADHD) and compared to a matched control sample of 652 individuals without elevations of ADHD or SCT (age range = 5.9-15.4 years). Multiple regression analyses revealed that symptoms of SCT were independently associated with deficits in nearly all domains assessed by a battery of neuropsychological assessments, including slower processing speed, poorer working memory, decreased inhibition, poorer vigilance, and increased reaction time. Further, weaknesses in all five of these domains remained significant even after symptoms of ADHD-inattention, anxiety, and depression were controlled. These findings add to literature that supports the validity of SCT as a symptom profile separate from ADHD-inattention symptoms.

Examining the Role of Attention Deficits in the Social Problems and Withdrawn Behavior of Children With Sluggish Cognitive Tempo Symptoms

Previous studies have found that sluggish cognitive tempo (SCT) symptoms are often associated with social problems and withdrawn behavior. However, the possible neuropsychological mechanism underlying this relationship remains unclear. Some studies have also found that SCT symptoms are related to deficits in sustained attention and selective attention. However, no study has examined whether attention deficits are related to social problems and withdrawn behavior in children with SCT. This study was the first to examine the neuropsychological correlates of social problems and withdrawn behavior among children with SCT symptoms. The results showed that sustained attention measure (omission) predicted the severity of social problems and withdrawn behavior in children with SCT even after controlling for symptoms of attention-deficit hyperactivity disorder. Selective attention measure (response latency mean) was also found to predict the severity of social problems. These results suggest that the social problems commonly exhibited by children with SCT are related to deficits in sustained attention and attentional control. Thus, our results provide an initial support to the link between attention deficits and social problems among children with SCT.

Physiological Correlates of Sluggish Cognitive Tempo in Children: Examining Autonomic Nervous System Reactivity during Social and Cognitive Stressor Tasks

It is important to establish correlates of sluggish cognitive tempo (SCT) across units of analysis and to better understand how SCT may be conceptualized in models of psychopathology. The current study examined SCT symptoms in relation to automatic nervous system reactivity during social and cognitive stressor tasks. Participants were 61 children ages 8-12 years with a full range of attention-deficit/hyperactivity disorder (ADHD) symptom severity. Parents provided ratings of SCT and parents and teachers completed measures that were used to create composite indices of ADHD symptoms. Children were administered standardized peer rejection and impossible puzzle tasks, during which their respiratory sinus arrhythmia (RSA) and skin conductance level (SCL) reactivity were recorded. Regression analyses indicated that SCT symptoms were unassociated with RSA reactivity to either task. Greater SCT symptoms were significantly associated with greater SCL reactivity to peer rejection. Greater SCT symptoms were not significantly associated with SCL reactivity to the impossible puzzle task. The pattern of findings was unchanged in sensitivity analyses that controlled for ADHD symptoms, internalizing symptoms, medication status, or sex. This study provides the first evidence that SCT symptoms are associated with sympathetic nervous system reactivity. These findings suggest that SCT symptoms may be associated with greater behavioral inhibition system activation, and reactivity may be especially pronounced in social challenges.

Sluggish Cognitive Tempo and ADHD Symptoms in a Nationally Representative Sample of U.S. Children: Differentiation Using Categorical and Dimensional Approaches

A nationally representative sample of U.S. children was used to determine the empirical and clinical differentiation of sluggish cognitive tempo (SCT) and attention-deficit/hyperactivity disorder (ADHD) symptoms using both categorical and dimensional approaches. Mothers of children (N = 2,056, M± SD_age = 8.49 ± 2.15 years, 49.3% girls) completed measures of SCT, ADHD, oppositional defiant disorder (ODD), anxiety, depression, sleep difficulties, daily life executive functioning, conflicted shyness, friendship difficulties, and social and academic impairment. Scores greater than the top 5% on SCT and ADHD measures were used to create SCT-only (n = 53, 2.58%), ADHD-only (n = 93, 4.52%), SCT+ADHD (n = 49, 2.38%), and comparison (n = 1,861, 90.52%) groups. Fifty-two percent of the SCT group did not qualify for the ADHD group, whereas 65% of the ADHD group did not qualify for the SCT group. The SCT-only group had higher levels of anxiety, depression, conflicted shyness, and sleep difficulties than the ADHD-only group. In contrast, the ADHD-only group had greater executive functioning deficits and higher ODD than the SCT-only group. SCT-only and ADHD-only groups showed similar levels of friendship, social, and academic impairment. Similar findings emerged when using structural regression analyses to determine the unique clinical correlates of SCT and ADHD dimensions. This is only the second study to examine the distinction of clinically-elevated SCT from ADHD in a national sample of children and extends previous findings to a broader array of functional outcomes. Normative information on the SCT scale also provides a validated rating scale to advance research and clinical care.

Initial Examination of the Bidirectional Associations between Sluggish Cognitive Tempo and Internalizing Symptoms in Children

Few studies have examined the longitudinal association between sluggish cognitive tempo (SCT) symptoms and internalizing symptoms, and no study has examined the potentially bidirectional associations between SCT and internalizing symptoms. The present study used a short-term longitudinal design to examine the directionality of the associations between SCT, depressive, and anxious symptoms in children. Teachers of 188 children in 1st to 6th grades (6-13 years of age; 47% boys) provided ratings of children's SCT, anxiety, and depressive symptoms in the fall school semester (T1) and again 6 months later (T2). Children in 3rd to 6th grades (n = 133) provided ratings of anxiety and depressive symptoms at both time points. Cross-lagged panel models examining the longitudinal associations between SCT, anxiety, and depressive symptoms were conducted controlling for sex and grade, with separate models for teacher- and child-reported internalizing symptoms. SCT symptoms at Time 1 (T1) predicted increased depressive symptoms at T2, with findings consistent across teacher-rated depression and child-rated depression. Depression at T1 did not predict SCT at T2. SCT symptoms at T1 also predicted increased teacher-rated anxiety at T2 but not child-rated anxiety. Finally, child-rated anxiety at T1 predicted increased SCT at T2. Findings from this study provide the first evidence that SCT symptoms predict subsequent depressive symptoms and not the reverse. Associations between SCT and anxiety are more nuanced, with results differing based on the informant. Additional studies are needed to replicate and extend these findings across longer developmental periods with more time points and to examine mechanisms of the associations between SCT and internalizing symptoms in children.