•Adolescent idiopathic scoliosis (AIS) shows altered electrocortical dynamics during balance control.•Cortical dynamics assessment seems sensitive to detect sensorimotor dysfunction.•Participants ...with AIS adapt their electrocortical dynamics to maintain balance control.
This study aims at examining the cortical dynamics of sensorimotor information processing related to balance control in participants with adolescent idiopathic scoliosis (AIS) and in age-matched controls (CTL).
Cortical dynamics during standing balance control were assessed in 13 girls with AIS and 13 age-matched controls using electroencephalography. Time-frequency analysis were used to determine frequency power during ankle proprioception alteration (ankle tendons co-vibration interval) or reintegration of ankle proprioception (post-vibration interval) with or without vision.
Balance control did not differ between groups. In the co-vibration interval, a significant suppression in alpha (8–12 Hz) and beta (13–30 Hz) band power and a significant increase in theta (4–7 Hz) band power were found respectively in the vision and non-vision condition in the AIS group compared to the CTL group. In the post-vibration interval, significant suppressions in beta (13–30 Hz) and gamma (30–50 Hz) band power were observed in the AIS group in the non-vision condition.
Participants with AIS showed brain oscillations differences compared to CTL in the sensorimotor cortex while controlling their balance in various sensory conditions.
Future study using evaluation of cortical dynamics could serve documenting whether rehabilitation programs have an effect on sensorimotor function in AIS.
•FXS patients show specific alterations in AEPs that exceed immaturity.•VEPs appear immature in FXS.•AEPs are more disrupted than VEPs in FXS.•Deficient synaptic pruning and neuronal inhibition might ...account for altered AEP/VEPs.
Fragile X Syndrome (FXS) is the most common monogenic form of intellectual disability and one of the few known monogenic causes of autism. It is caused by a trinucleotide repeat expansion in the FMR1 (‘Fragile X Mental Retardation 1’) gene, which prevents expression of the ‘Fragile X Mental Retardation Protein’ (FMRP). In FXS, the absence of FMRP leads to altered structural and functional development of the synapse, while preventing activity-based synapse maturation and synaptic pruning, which are essential for normal brain development and cognitive development. Possible impairments in information processing can be non-invasively investigated using electrophysiology.
We compared auditory (AEP) and visual (VEP) evoked potentials in twelve adolescents and young adults (10–22 years) affected by FXS to healthy controls matched by chronological age (N=12) and developmental age of cognitive functioning (N=9; 5–7 years), using analysis of variance.
In the visual modality, the N70 and N2 amplitude have been found increased in FXS in comparison to the chronological, but not the developmental control group at occipital sites, whereas in the auditory modality N1, P2 and N2 amplitude as well as N2 latency have been found increased in FXS, relative to both chronological and developmental control groups at mid-central sites.
The AEP/VEP profile suggests disruptions in sensory processing specific to FXS that exceed immaturity of physiological activity. In addition, the auditory modality seems to be more affected than the visual modality. Results are discussed in light of possible underlying neuronal mechanisms, including deficits in synaptic pruning and neuronal inhibition that might account for a hyperreactive nervous system in FXS.
For newborns and neonates, ultrasound (US) is the most common imaging modality used for examinations due to its accessibility and ease of use. However, precise volume measurements remain limited in ...2D, while MRI in newborns is typically avoided because of immobilization issues which may require sedation. The objective of this study is to assess and validate the lateral ventricular and total brain volumes obtained with an automatic segmentation method using cerebral trans-fontanelle 3D US. Infants aged between 2 and 8.5 months old were recruited, with both MRI and 3D US acquired on the same day was used to validate ventricular and brain volume measurements in comparison to MRI. Lateral ventricles were segmented on both the US (manually and with a proposed automatic fusion-based approach) and MRI, while brain volumes were estimated with an automatic segmentation method. Volumetric 3D US measurements were then evaluated with respect to age distribution. For the comparison between MRI and 3D US, strong inter-class correlations (ICC) were found for the ventricle volumes (manual: 5.9% ± 2.5% difference (ICC = 0.99); automatic: 6.0% ± 2.6% difference (ICC = 0.98)), as well as the total brain size, with a 3.0% ± 1.3% difference (ICC = 0.98). There was no statistically significant difference based on t-test and f-test for the lateral ventricles volume (t-test: p = 0.542) and (f-test: p = 0.738) and for the total brain volume (t-test: p = 0.412) and (f-test: p = 0.685) between MRI and 3D US. This study demonstrates that 3D US can be used to automatically assess lateral ventricular and total brain volumes with no significant difference to the MRI acquisitions. The highest correlations were obtained for infants under 8 months when the fontanelle is open.
Genomic copy number variants (CNVs) are routinely identified and reported back to patients with neuropsychiatric disorders, but their quantitative effects on essential traits such as cognitive ...ability are poorly documented. We have recently shown that the effect size of deletions on cognitive ability can be statistically predicted using measures of intolerance to haploinsufficiency. However, the effect sizes of duplications remain unknown. It is also unknown if the effect of multigenic CNVs are driven by a few genes intolerant to haploinsufficiency or distributed across tolerant genes as well. Here, we identified all CNVs > 50 kilobases in 24,092 individuals from unselected and autism cohorts with assessments of general intelligence. Statistical models used measures of intolerance to haploinsufficiency of genes included in CNVs to predict their effect size on intelligence. Intolerant genes decrease general intelligence by 0.8 and 2.6 points of intelligence quotient when duplicated or deleted, respectively. Effect sizes showed no heterogeneity across cohorts. Validation analyses demonstrated that models could predict CNV effect sizes with 78% accuracy. Data on the inheritance of 27,766 CNVs showed that deletions and duplications with the same effect size on intelligence occur de novo at the same frequency. We estimated that around 10,000 intolerant and tolerant genes negatively affect intelligence when deleted, and less than 2% have large effect sizes. Genes encompassed in CNVs were not enriched in any GOterms but gene regulation and brain expression were GOterms overrepresented in the intolerant subgroup. Such pervasive effects on cognition may be related to emergent properties of the genome not restricted to a limited number of biological pathways.
•Cortisol concentrations are associated with EEG repetition suppression in infants.•Cortisol concentrations influence vigilance and the orienting response in infants.•Vigilance and the orienting ...response in infants change with age.
Over activation of the hypothalamo–pituitary–adrenal (HPA) axis in stress situations is known to influence learning and memory. In adults, an inverted-U shape relationship between acute stress, and learning and memory has been demonstrated. Whether this model fits learning performances in infants is unknown. In this study, we used EEG repetition suppression as physiological measure of learning and salivary cortisol in response to a stressor to investigate the relationship between acute stress and learning in infants. We hypothesized that EEG repetition suppression would be modulated by acute stress following an inverted-U shape relationship. Saliva samples were collected during an EEG experiment before, during and after EEG net installation in 37 healthy infants (18 males) aged between 6 and 26 months. The effect of variation in stress hormones on repetition suppression were modeled using a linear mixed model, with cortisol, age and sex as predictors. Results indicated that in healthy infants, elevations in stress hormones within the normal range are associated with a higher repetition suppression response and an increased response to the first presentation of the stimulus. The later increase could be related to vigilance. Considering that early childhood is a critical period of development, future studies should keep investigating the influence of stress on learning processes in infants.
•We found abnormal brain activity to a habituation paradigm after complex FS.•Children with prolonged FS show brain hyperactivity to a habituation paradigm.•Children with multiple and focal FS show ...impaired neural habituation.•Opposite patterns depending on FS type suggests different underlying mechanisms.•Abnormal activity could impact FS characteristics, including cognitive prognosis.
Studies have identified mild but persistent cognitive and functional deficits, which could be linked to each other, in children with complex febrile seizures (FS). Our aim was to investigate differences in brain activity in children with a history of complex FS, through a study paradigm notably associated with the development of learning capacities and using electroencephalographic (EEG) signal. To further increase our understanding of these differences, complex FS were studied separately depending on their type.
EEG was recorded in 43 children with past FS. Brain activity associated with auditory learning was investigated using a habituation paradigm, in which repetition suppression (RS) is typically found following stimulus repetition. Auditory stimuli were repeated three times, and each presentation were analysed separately in the time-frequency (TF) domain. A mixed-analysis of variance was used to assess differences in spectral power between stimulus repetition and FS type (simple vs complex prolonged; CP vs complex unprolonged; CUP).
Repetition effects were found in the 3–6 Hz during 150–600 ms time window after stimulus onset at frontal sites (F(2, 40) = 5.645, p = 0.007, η2p = 0.220). Moreover, an interaction effect between stimulus repetition and FS type (F(4, 80) = 2.607, p = 0.042, η2p = 0.115) was found. Children with CP FS showed greater increase in spectral power in response to the first stimulus presentation, while children with CUP FS failed to show a RS pattern.
Our results show distinct abnormalities in brain activity to a habituation paradigm. We argue that these changes suggest children with CP FS may be hyperexcitable, while children with CUP FS show impaired habituation processes. Still, these differences may be associated with other clinical features linked to complex FS as well. Hence, the role of these differences in complex FS incidence and prognosis should be the subject of future studies.
Nighttime in Dreams Schredl, Michael; Knoth, Inga Sophia
Perceptual and motor skills,
04/2012, Letnik:
114, Številka:
2
Journal Article
Recenzirano
Based on the continuity hypothesis of dreaming, a study was designed to examine whether time of day within the dream was related to dream emotions. A sample of 1,612 dreams reported by 444 ...participants was analyzed. As predicted, dream scenarios set at nighttime were associated with less positive and more negative emotions compared to dream scenarios set at other times of the day. In order to pursue this line of research, it would be fruitful to study the dreams of persons with specific nighttime fears.
Objective. Our goal was to assess development, cognition and behaviour following an initial complex febrile seizure (FS), at onset and school age, in the context of known risk factors for cognitive ...development.
Methods. Two cohorts were recruited. Thirty‐five infants with an initial complex FS were assessed within the first year post‐seizure and compared to 30 controls (simple FS) based on measures of cognitive, motor and language development, behaviour and emotions. Additionally, 19 school‐age children with previous complex FS (11 multiple, eight prolonged) were assessed and compared to 19 controls (simple FS) based on measures of intelligence, learning/memory, executive functioning, behaviour and emotions.
Results. Within the first year post‐onset, infants with complex FS did not significantly differ from controls based on developmental measures. Seizure duration and age at seizure onset did not impact developmental outcome. School‐age children with complex FS showed unaltered global intelligence, but lower executive functioning, compared to controls. Children with prolonged FS also showed evidence of a lower level of learning and memory abilities. Neuropsychological scores correlated with seizure duration. Children with complex FS showed more attentional problems and anxious/depressed symptomatology at onset and school age, and more hyperactivity at school age.
Significance. Infants with complex FS seemed to show normal development within the first year post‐seizure onset. However, challenges in executive functioning, learning and memory at school age were found in children with a history of FS. Hence, at school age, cognitive challenges cannot be excluded based on undifferentiated early cognitive development, and may occur even in the absence of the most severe form of FS (i.e., FSE). Beyond the limits of this study (i.e., small sample size, use of parental questionnaires for emotional/behavioural outcome, absence of focal cases in the school‐age cohort), our results suggest that a follow‐up is necessary beyond the early preschool years in order to understand the long‐term outcome.
Studies suggest that the relationship between seizures and stress starts early in life. However, evidence of long-term altered stress reactivity following early-life seizures is lacking. Our ...objectives were to assess alterations in stress hormone reactivity in children with past febrile seizures (FS) and investigate how these alterations relate to clinical characteristics.
This case–control study compared a convenience sample of children with simple FS (n = 24), complex FS (n = 18), and matched healthy controls (n = 42). Stress was induced by electrode placement for an electroencephalography (EEG) exam. Salivary cortisol to stress, using three samples collected before and after the stressor, was compared between groups and sex. The relationship between stress reactivity and clinical characteristics (i.e., FS duration, age at first FS, time since the last FS) was investigated.
Cortisol reactivity to stress was significantly different depending on study groups, F(1, 78) = 6.415, p = 0.003, η2p = 0.141, but not sex nor was there a significant interaction between group and sex (p ≥ 0.581). Participants with simple FS showed higher cortisol reactivity to stress (M = 14.936, Standard deviation (SD) = 26.852) compared with those with complex FS (M = −4.663, SD = 18.649, p = 0.015) and controls (M = −3.817, SD = 18.907, p = 0.003). There was no significant difference between participants with complex FS and controls (p > 0.999). Stress reactivity was not linked to clinical characteristics.
Children with past simple FS showed greater changes in salivary cortisol following stress, suggesting enhanced stress sensitivity. As similar results were not found in a population with complex FS, our study shows that stress alterations are not caused by seizure severity. Future studies are needed to investigate whether stress sensitivity may be premorbid to simple FS and may contribute to simple FS incidence.
•Human studies showing a seizure–stress relationship in early childhood are lacking.•History of simple febrile seizures is associated with increased stress sensitivity.•Increased stress sensitivity is not a cause of febrile seizure severity.
Le syndrome du X fragile (SXF) est la première cause héréditaire de déficience intellectuelle et également la première cause monogénique d’autisme. Le SXF est causé par l'expansion de la répétition ...du nucléotide CGG sur le gène FMR1, ce qui empêche l’expression de la protéine FMRP. L’absence du FMRP mène à une altération du développement structurel et fonctionnel de la synapse, ce qui empêche la maturation des synapses induite par l’activité et l’élagage synaptique, qui sont essentiels pour le développement cérébral et cognitif. Nous avons investigué les potentiels reliés aux événements (PRE) évoqués par des stimulations fondamentales auditives et visuelles dans douze adolescents et jeunes adultes (10-22) atteints du SXF, ainsi que des participants contrôles appariés en âge chronologique et développemental. Les résultats indiquent un profil des PRE altéré, notamment l’augmentation de l’amplitude de N1 auditive, par rapport aux deux groupes contrôle, ainsi que l’augmentation des amplitudes de P2 et N2 auditifs et de la latence de N2 auditif. Chez les patients SXF, le traitement sensoriel semble être davantage perturbé qu’immature. En outre, la modalité auditive semble être plus perturbée que la modalité visuelle. En combinaison avec des résultats anatomique du cerveau, des mécanismes biochimiques et du comportement, nos résultats suggèrent une hyperexcitabilité du système nerveux dans le SXF.
We investigated early auditory and visual information processing in Fragile X Syndrome (FXS), the most common form of X-linked Intellectual Disability (ID) and the only known monogenetic cause of autism. FXS is caused by a trinucleotide repeat expansion in the FMR1 (‘Fragile X mental retardation 1’) gene, which prevents expression of the ‘fragile X mental retardation protein’ (FMRP). FMRP absence leads to altered structural and functional development of the synapse, while also preventing activity-based synapse maturation and synaptic pruning, which are essential for cerebral and cognitive development. We review the contribution of electrophysiological signal studies for the understanding of information processing in FXS and compare event-related potential (ERP) findings to those concerning other clinical populations that share symptoms with FXS. In our research project, we investigated ERPs evoked by basic auditory and visual stimulation in twelve adolescents and young adults (10-22) with FXS, as well as healthy chronological- and developmental- age matched controls. We found an altered ERP profile in FXS, including increased auditory N1 amplitude, relative to both control groups, as well as increased auditory P2 and N2 amplitudes and increased auditory N2 latencies. Rather than being immature, sensory processing appears to be specifically disrupted in FXS. Furthermore, the auditory modality seems to be more affected than the visual modality. In combination with brain anatomical, biochemical and behavioural findings, our results suggest a hyperexcitable nervous system in FXS.
PDF
