Association of indoor dust microbiota with cognitive function and behavior in preschool-aged children

BACKGROUND

Childhood cognitive development depends on neuroimmune interactions. Immunomodulation by early-life microbial exposure may influence neuropsychological function. In this study, we investigate the association between residential indoor microbiota and cognition and behavior among preschoolers.

RESULTS

Indoor-settled dust bacterial and fungal characteristics were assessed using 16S and ITS amplicon sequencing (microbial diversity) and qPCR measurements (microbial loads). Child behavior was assessed using four scales: peer relationship, emotional, conduct, and hyperactivity was assessed by the Strengths and Difficulties Questionnaire (SDQ). Cognitive function was assessed using four tasks of the Cambridge Neuropsychological Test Automated Battery (CANTAB) software. The first two tasks were designed to assess attention and psychomotor speed (Motor Screening (MOT) and Big/Little Circle (BLC)) and the last two to evaluate the child's visual recognition/working memory (Spatial Span (SSP) and Delayed Matching to Sample (DMS)). Among the 172 included children (age 4-6 years), we observed a 51% (95%CI;75%;9%) lower odds of children scoring not normal for hyperactivity and a decrease of 3.20% (95%CI, -6.01%; -0.30%) in BLC response time, for every IQR increase in fungal Shannon diversity. Contrarily, microbial loads were directly associated with SDQ scales and response time. For example, a 2-fold increase in Gram-positive bacterial load was associated with 70% (95%CI 18%; 156%) higher odds of scoring not normal for hyperactivity and an increase of 5.17% (95%CI 0.87%; 9.65%) in DMS response time.

CONCLUSIONS

Our findings show that early-life exposure to diverse indoor fungal communities is associated with better behavioral and cognitive outcomes, whereas higher indoor microbial load was associated with worse outcomes. Video Abstract.

Early life exposure to residential green space impacts cognitive functioning in children aged 4 to 6 years

INTRODUCTION

During early childhood, neuronal networks are highly susceptible to environmental factors. Previous research suggests that green space exposure is beneficial for cognitive functioning. Here, we investigate the associations between residential green space exposure and behavioral problems and cognitive development in children aged four to six years.

METHOD

We included children participating in the ENVIRONAGE birth cohort. Residential green spaces were calculated based on high-resolution land cover data within several buffers (50-1,000 m) around the residence. The children's behavior was assessed with the Strengths and Difficulties Questionnaire (SDQ) among 411 children. In addition, to evaluate cognitive function, 456 children completed four tasks of the Cambridge Neuropsychological Test Automated Battery (CANTAB). We used multivariate logistic and linear regression models while accounting for potential confounders and covariables.

RESULTS

An interquartile (IQR) increase of residential green space within 50 m was associated with a 38% (95% CI: 56;14) lower odds of a child having hyperactivity problems. Additionally, we found a beneficial influence of residential green space in close proximity (50-100 m) on the attention and psychomotor speed, represented by the Motor Screening Task. For example, we found a decrease of 0.45 (95% CI: -0.82;-0.09) pixel units from target center with an IQR increase of residential green space in a 50 m buffer. In addition, we observed an improved visual recognition/working memory, represented by the Delayed Matching to Sample Task within all included buffers (50-1000 m). For example, we observed a decrease of 4.91% (95 %CI: -7.46;-2.36) probability of an error occurring if the previous trial was correct and a 2.02% (95 %CI: 0.08; 3.97) increase of correct trials with an IQR increase of green space within a 100 m buffer.

CONCLUSION

This study provides additional indications for a beneficial influence of green space exposure on the development of behavioral problems and cognitive function as young as four years of age.

Deep brain stimulation for treatment-resistant major depressive disorder: a comparison of two targets and long-term follow-up

We previously found that electrical stimulation in the anterior limb of the internal capsule/bed nucleus of the stria terminalis (IC/BST) alleviates depressive symptoms in severe treatment-resistant obsessive-compulsive disorder (OCD) patients. Here we tested the hypothesis that electrical stimulation in either IC/BST or in the inferior thalamic peduncle (ITP) effectively reduces depressive symptoms in treatment-resistant major depressive disorder (TRD). In a double-blind crossover design, the effects of electrical stimulation at both targets were compared in TRD patients. The 17-item Hamilton Depression Rating scale (HAM-D) was the primary outcome measure. During the first crossover, patients received IC/BST stimulation versus no stimulation in random order (2 × 1 weeks). During the second crossover (3 × 2 months), patients received IC/BST versus ITP versus no stimulation. Patients and evaluators were blinded for stimulation conditions. All patients (n=7) were followed up for at least 3 years (3-8 years) after implantation. Six patients completed the first crossover and five patients completed the second. During the first crossover, mean (s.d.) HAM-D scores were 21.5 (2.7) for no stimulation and 11.5 (8.8) for IC/BST stimulation. During the second crossover, HAM-D scores were 15.4 (7.5) for no stimulation, 7.6 (3.8) for IC/BST stimulation and 11.2 (7.5) for ITP stimulation. The final sample size was too small to statistically analyze this second crossover. At last follow-up, only one patient preferred ITP over IC/BST stimulation. Two patients, with a history of suicide attempts before implantation, committed suicide during the follow-up phases of this study. Our data indicate that, in the long term, both ITP and IC/BST stimulation may alleviate depressive symptoms in patients suffering from TRD.

Long-term electrical stimulation of bed nucleus of stria terminalis for obsessive-compulsive disorder

We previously reported that bilateral electrical stimulation in the anterior limb of the internal capsule/bed nucleus of the stria terminalis (IC/BST) effectively reduces symptoms in severe treatment-resistant obsessive-compulsive disorder (OCD) patients. Here we used a linear mixed model to investigate the evolution of symptomatic and functional status of our patients (n=24) and examined if baseline variables could predict this evolution. Data were collected during routine, clinical psychiatric visits. Our analysis showed a long-term, sustained effect of electrical stimulation in the IC/BST. After a fast initial decline of OCD symptoms, these symptoms remain relatively stable. In addition, we found a strong ON/OFF effect of stimulation (e.g., due to battery depletion). Our data also show that it is not the surgical procedure but rather the electrical stimulation that drives the improvement in Yale-Brown Obsessive-Compulsive Scale (Y-BOCS) scores. The Beck Depression Inventory (BDI) at baseline was the only predictor significantly related to the evolution of the Y-BOCS. A higher BDI at baseline seemed to be related to a smaller decrease of the Y-BOCS over time. In conclusion, electrical stimulation in the IC/BST has a fast and sustained effect on OCD and comorbid symptoms and functional status of patients.

Deep brain stimulation and anterior capsulotomy: The question of autonomy

Introduction

In carefully selected treatment-refractory patients with obsessive compulsive disorder (OCD), deep brain stimulation (DBS) or anterior capsulotomy (AC) might be considered as a possible treatment. However, the direct intervention in the brain can raise questions about autonomy. Do patients still feel like they are in control of their actions when their behavior is changed by a surgical intervention?

Objective/aims

To examine in both AC and DBS patients whether these intervention influenced perception of autonomy. We aimed to discover any differences in these perceptions when comparing AC and DBS patients.

Methods

We conducted semi-structured interviews with AC and DBS patients. Interviews were recorded digitally and transcribed verbatim. We analyzed interviews in an iterative process based on grounded theory principles.

Results

We interviewed 10 DBS patients and 6 AC patients. Sense of agency (the awareness that one is the author of his/her own actions) did not seem to be diminished by AC or DBS. However, especially DBS patients are aware of their dependency on a device for their well-being. Another important theme is authenticity (in how far patients perceive their actions and thoughts as matching their self-concept). Feelings of authenticity can be disturbed especially in cases of induced hypomania (for DBS) or apathy (for AC). OCD itself also has an impact on autonomy as patients describe a lack of freedom due to their disorder.

Conclusion

Despite extensive changes in emotions, behavior and even personal identity after DBS or AC surgery, perceived autonomy was not greatly altered in these OCD patients.

Disclosure of interest

Medtronic provided grants for research, education, and traveling to B. Nuttin and L. Gabriëls, who hold the Medtronic Chair for Stereotactic Neurosurgery in Psychiatric Disorders at KU Leuven. S. Raymaekers is supported by this Chair. B. Nuttin co-owns a patent on DBS in OCD.

Electrical stimulation in the bed nucleus of the stria terminalis alleviates severe obsessive-compulsive disorder

In 1998, we proposed deep brain stimulation as a last-resort treatment option for patients suffering from severe, treatment-resistant obsessive-compulsive disorder (OCD). Here, 24 OCD patients were included in a long-term follow-up study to evaluate the effects of electrical stimulation in the anterior limbs of the internal capsule (ALIC) and bed nucleus of the stria terminalis (BST). We find that electrical stimulation in the ALIC/BST area is safe and significantly decreases obsessions, compulsions, and associated anxiety and depressive symptoms, and improves global functioning in a blinded crossover trial (n=17), after 4 years (n=18), and at last follow-up (up to 171 months, n=24). Moreover, our data indicate that BST may be a better stimulation target compared with ALIC to alleviate OCD symptoms. We conclude that electrical stimulation in BST is a promising therapeutic option for otherwise treatment-resistant OCD patients.

No effect of glucose administration in a novel contextual fear generalization protocol in rats

The excessive transfer of fear acquired for one particular context to similar situations has been implicated in the development and maintenance of anxiety disorders, such as post-traumatic stress disorder. Recent evidence suggests that glucose ingestion improves the retention of context conditioning. It has been speculated that glucose might exert that effect by ameliorating hippocampal functioning, and may hold promise as a therapeutic add-on in traumatized patients because improved retention of contextual fear could help to restrict its generalization. However, direct data regarding the effect of glucose on contextual generalization are lacking. Here, we introduce a new behavioral protocol to study such contextual fear generalization in rats. In adult Wistar rats, our procedure yields a gradient of generalization, with progressively less freezing when going from the original training context, over a perceptually similar generalization context, to a markedly dissimilar context. Moreover, we find a flattening of the gradient when the training-test interval is prolonged with 1 week. We next examine the effect of systemic glucose administration on contextual generalization with this novel procedure. Our data do not sustain generalization-reducing effects of glucose and question its applicability in traumatic situations. In summary, we have developed a replicable contextual generalization procedure for rats and demonstrate how it is a valuable tool to examine the neurobiological correlates and test pharmacological interventions pertaining to an important mechanism in the etiology of pathological anxiety.

Long-term electrical stimulation of bed nucleus of stria terminalis for obsessive-compulsive disorder

Introduction

We previously reported that deep brain stimulation (DBS) in the anterior limb of the internal capsule/bed nucleus of the stria terminalis (IC/BST) is effective in reducing symptoms in severe treatment-resistant obsessive-compulsive disorder patients.

Objective

To examine the long-term evolution of obsessive compulsive disorder (OCD) symptoms in 24 patients treated with chronic electrical stimulation in IC/BST.

Aims

We aimed to examine the evolution of the Yale-Brown Obsessive Compulsive Scale (Y-BOCS) and to determine if a number of predictors assessed before surgery are significantly related to this evolution.

Methods

We used a linear mixed model to investigate the evolution of the Y-BOCS in 24 patients. Data was collected in a naturalistic manner. Seven hundred measurements, taken during a total of 1836 follow-up months, are included in this analysis.

Results

Our analysis showed a long-term, sustained effect of electrical stimulation in the IC/BST. After a fast initial decline of OCD symptoms, these symptoms stay relatively stable. In addition, results show a strong ON/OFF effect of stimulation (e.g., due to battery depletion). Beside the ON/OFF effect of stimulation, the surgery itself has no additional effect on OCD symptoms. The Beck Depression Inventory (BDI) at baseline was the only predictor significantly related to the evolution of the Y-BOCS. A higher BDI at baseline seemed to be related to a smaller decrease of the Y-BOCS over time.

Conclusion

Electrical stimulation in the IC/BST has a fast and sustained effect on OCD symptoms.

Disclosure of interest

The authors have not supplied their declaration of competing interest.

Task perception as a mediating variable: a contribution to the validation of instructional knowledge

BACKGROUND

From the perspective of the cognitive mediational paradigm, we focus in this study on students' conceptions of the relationship between instructional interventions and learning: 'instructional knowledge'.

AIMS

Task perception has been investigated as a procedural manifestation of instructional knowledge. Four research questions directed the study: (1) how do students perceive a task; (2) by which structure can the relations between categories of task perception be represented; (3) do students differ in their task perception; and (4) is there a significant relationship between students' task perception and the learning activities they plan and/or execute.

SAMPLE

The sample consisted of 149 university freshmen in educational sciences.

METHODS

Students were confronted with a concrete task in a natural setting. Correlations were searched for by phi coefficient. Hierarchical classes analysis was used to search for hierarchical relations and inter-individual differences. Goodman-Kruskal lambda was calculated to estimate the association between students' task perception and the learning activities they planned and executed. The questionnaire and the design of the coding systems were first tried out in a pilot study.

RESULTS

Students' task perception can be described in 11 categories. Correlations between those categories were low, but a simple hierarchical structure was discovered. Students can be distinguished according to their task perception into eight groups. Finally, the results indicate a statistically significant association between students' task perception and the learning activities they plan and execute.

CONCLUSIONS

The study provides additional evidence to involve 'instructional knowledge' and students' task perception as part of it, as mediating variables in future research.