Investigating the structure of the restricted, repetitive behaviours and interests domain of autism

BACKGROUND: The Restricted, Repetitive Behaviours and Interests (RRBIs) are represented in the DSM-IV and measured by the Autism Diagnostic Interview-Revised (ADI-R) as one of the three homogeneous symptom categories of Pervasive Developmental Disorders. Although this conceptualisation is well accepted in the field, the grouping of symptoms is based primarily on clinical judgment rather than on empirical evidence. METHODS: The objective of this study was to examine the factor structure of the RRBI domain of autism. Eleven items from this domain of the ADI-R were used in a Principal Components Analysis (PCA). Our sample consisted of 339 individuals with a Best Estimate diagnosis of Pervasive Developmental Disorder (PDD). RESULTS: Findings indicate that the RRBI domain is composed of two distinct factors or dimensions: Insistence on Sameness (IS) and Repetitive Sensory and Motor Behaviours (RSMB). RSMB is negatively correlated with adaptive skills; that is, lower functioning individuals tend to have higher levels of repetitive sensory and motor behaviours. On the other hand, IS is positively correlated with autistic symptoms in the communication and language domain. Further analyses suggest moderate familial aggregation among affected sibling pairs within the IS but not the RSMB factor. CONCLUSIONS: These results provide evidence for the heterogeneity of the RRBI domain of the ADI-R in terms of both clinical presentation and other correlates. In addition, the IS factor seems to be under familial (presumably genetic) control, while RSMB appears to simply reflect variation in developmental level.     

Factor Structure of Repetitive Behaviors Across Autism Spectrum Disorder and Attention-Deficit/Hyperactivity Disorder

Journal of Autism and Developmental Disorders - Restricted interests and repetitive behaviors (RRBs) are core symptoms of autism spectrum disorder (ASD), and commonly occur in...     

Subthalamic Nucleus Activity during Cognitive Load and Gait Dysfunction in Parkinson's Disease

Background

Gait freezing is a common, disabling symptom of Parkinson's disease characterized by sudden motor arrest during walking. Adaptive deep brain stimulation devices that detect freezing and deliver real-time, symptom-specific stimulation are a potential treatment strategy. Real-time alterations in subthalamic nucleus firing patterns have been demonstrated with lower limb freezing, however, whether similar abnormal signatures occur with freezing provoked by cognitive load, is unknown.

Methods

We obtained subthalamic nucleus microelectrode recordings from eight Parkinson's disease patients performing a validated virtual reality gait task, requiring responses to on-screen cognitive cues while maintaining motor output.

Results

Signal analysis during 15 trials containing freezing or significant motor output slowing precipitated by dual-tasking demonstrated reduced θ frequency (3–8 Hz) firing compared to 18 unaffected trials.

Conclusions

These preliminary results reveal a potential neurobiological basis for the interplay between cognitive factors and gait disturbances including freezing in Parkinson's disease, informing development of adaptive deep brain stimulation protocols. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.     

Editorial Perspective: Longitudinal research in autism – introducing the concept of ‘chronogeneity’

Autism Spectrum Disorder (ASD or autism) is a heterogeneous neurodevelopmental disorder. We are now at a critical juncture in autism research where we have the knowledge base and expertise to begin to think about studies that view heterogeneity, not as ‘statistical noise’ that can be ‘accounted for’ using data‐reduction techniques (such as group trajectories), but rather as ‘informative variance’ that can help form a more precise and dynamic picture of autism. In this Editorial we coin a new term and introduce the concept of ‘chronogeneity’ for the study of autism heterogeneity in relation to the dimension of time (chrono). Using examples of ongoing research and analytical advances we build the case for the potential utility of the concept of ‘chronogeneity’ and argue that a refined approach to the longitudinal investigation of autism (and other neurodevelopmental disorders) may move us closer to more precise and adaptive models of care for the children and youth affected by these disorders.     

Exercise and weight loss reduce blood pressure in men and women with mild hypertension: effects on cardiovascular, metabolic, and hemodynamic functioning

BACKGROUND: Lifestyle modifications have been recommended as the initial treatment strategy for lowering high blood pressure (BP). However, evidence for the efficacy of exercise and weight loss in the management of high BP remains controversial. METHODS: One hundred thirty-three sedentary, overweight men and women with unmedicated high normal BP or stage 1 to 2 hypertension were randomly assigned to aerobic exercise only; a behavioral weight management program, including exercise; or a waiting list control group. Before and following treatment, systolic and diastolic BPs were measured in the clinic, during daily life, and during exercise and mental stress testing. Hemodynamic measures and metabolic functioning also were assessed. RESULTS: Although participants in both active treatment groups exhibited significant reductions in BP relative to controls, those in the weight management group generally had larger reductions. Weight management was associated with a 7-mm Hg systolic and a 5-mm Hg diastolic clinic BP reduction, compared with a 4-mm Hg systolic and diastolic BP reduction associated with aerobic exercise; the BP for controls did not change. Participants in both treatment groups also displayed reduced peripheral resistance and increased cardiac output compared with controls, with the greatest reductions in peripheral resistance in those in the weight management group. Weight management participants also exhibited significantly lower fasting and postprandial glucose and insulin levels than participants in the other groups. CONCLUSIONS: Although exercise alone was effective in reducing BP, the addition of a behavioral weight loss program enhanced this effect. Aerobic exercise combined with weight loss is recommended for the management of elevated BP in sedentary, overweight individuals.     

Prevalence and Correlates of Physical-mental Multimorbidity in Outpatient Children From a Pediatric Hospital in Canada

ObjectiveThe aim of this study was to estimate the six-month prevalence of mental illness in children with chronic physical illness (multimorbidity), examine agreement between parent and child reports of multimorbidity, and identify factors associated with child multimorbidity.MethodThe sample included 263 children aged 2–16 years with a physician-diagnosed chronic physical illness recruited from the outpatient clinics at a pediatric hospital. Children were categorized by physical illness according to the International Statistical Classification of Diseases and Related Health Problems (ICD)-10. Parent and child-reported six-month mental illness was based on the Mini International Neuropsychiatric Interview for Children and Adolescents (MINI-KID).ResultsOverall, 101 (38%) of children had a parent-reported mental illness; 29 (25%) children self-reported mental illness. There were no differences in prevalence across ICD-10 classifications. Parent-child agreement on the MINI-KID was low (κ = 0.18), ranging from κ = 0.24 for specific phobia to κ = 0.03 for attention-deficit hyperactivity. From logistic regression modeling (odds ratio [OR] and 95% confidence interval), factors associated with multimorbidity were: child age (OR = 1.16 [1.04, 1.31]), male (OR = 3.76 [1.54, 9.22]), ≥$90,000 household income (OR = 2.57 [1.08, 6.22]), parental symptoms of depression (OR = 1.09 [1.03, 1.14]), and child disability (OR = 1.21 [1.13, 1.30]). Similar results were obtained when modeling number of mental illnesses.ConclusionsFindings suggest that six-month multimorbidity is common and similar across different physical illnesses. Level of disability is a robust, potentially modifiable correlate of multimorbidity that can be assessed routinely by health professionals in the pediatric setting to initiate early mental health intervention to reduce the incidence of multimorbidity in children.