Minor neurological dysfunction and IQ in 9-year-old children born at term

Neurological and Cognitive Performance After Childhood Encephalitis

Background: Children with encephalitis have increased risk for long-term neurological sequelae. We investigated minor neurological dysfunction (MND) and cognitive performance as a measurement for long-term outcome of encephalitis in childhood. Materials and Methods: Children with encephalitis (n = 98) treated in Turku University Hospital during the years 1995-2016 were retrospectively identified. We included the patients without severe developmental delay before the encephalitis and without recorded neurological disability caused by encephalitis. MND was assessed using the Touwen examination. Age-appropriate Wechsler Intelligence Scale was used to determine the full-scale intelligence quotient (IQ). Residual symptoms in everyday life were evaluated using a questionnaire. Results: Forty-two subjects participated in the study and returned the questionnaire regarding residual symptoms. The median age was 4.3 years at the time of encephalitis, and 11.3 years at the time of the Touwen examination (n = 41) and the cognitive assessment (n = 38). The Touwen examination indicated MND in 29 of 41 participants (71%; simple MND in 16 and complex MND in 13 patients). The median full-scale IQ was lower in participants with MND compared with participants without MND (98 vs. 110, p = 0.02). Participants with IQ < 85 (n = 5) had lower median age at acute encephalitis compared to participants with IQ ≥ 85 (n = 33) (1.8 vs. 5.3 years, p = 0.03). Problems in daily performance were reported in participant with MND (p = 0.2) and low full-scale IQ (p = 0.008). Conclusions: The prevalence of MND was high and it was related to lower cognitive performance after childhood encephalitis. Younger age at acute encephalitis was a risk factor for lower cognitive performance.

Analysis of neurodevelopmental outcomes of preadolescents born with extremely low weight revealed impairments in multiple developmental domains despite absence of cognitive impairment

BACKGROUND AND AIMS

Children with extremely low-birth weight (ELBW) have a high risk for cognitive, motor, and attention impairments and learning disabilities. Longitudinal follow-up studies to a later age are needed in order to increase understanding of the changes in neurodevelopmental trajectories in targeting timely intervention. The aims of this study were to investigate cognitive and motor outcomes, attention-deficit hyperactivity (ADHD) behaviour, school performance, and overall outcomes in a national cohort of ELBW children at preadolescence, and minor neuromotor impairments in a subpopulation of these children and to compare the results with those of full-term controls. The additional aim was to report the overall outcome in all ELBW infants born at 22 to 26 gestational weeks.

METHODS

This longitudinal prospective national cohort study included all surviving ELBW (birth weight <1000 g) children born in Finland in 1996 to 1997. No children were excluded from the study. Perinatal, neonatal, and follow-up data up to the age of 5 years of these children were registered in the national birth register. According to birth register, the study population included all infants born at the age under 27 gestational weeks. At 11 years of age general cognitive ability was tested with the Wechsler Intelligence Scale for Children, ADHD behavior evaluated with a report from each child's own teacher (ADHD Rating Scale IV), and school performance with a parental questionnaire. An ELBW subpopulation consisting of a cohort representative children from the two university hospitals from two regions (n = 63) and the age-matched full-term born controls born in Helsinki university hospital (n = 30) underwent Movement Assessment Battery for Children and Touwen neurological examination comprising developmental coordination disorder (DCD) and minor neurological dysfunction (MND), respectively.

RESULTS

Of 206 ELBW survivors 122 (73% of eligible) children and 30 (100%) full-term control children participated in assessments. ELBW children had lower full-scale intellectual quotient than controls (t-test, 90 vs 112, P < .001), elevated teacher- reported inattention scores (median = 4.0 vs 1.0, P = .021, r = .20) and needed more educational support (47% vs 17%, OR 4.5, 95% CI 1.6-12.4, P = .02). In the subpopulation, the incidences of DCD were 30% in ELBW and 7% in control children (P = .012, OR 6.0 CI 1.3-27.9), and complex MND 12.5% and 0%, (P = .052; RR 1.1 95% CI 1.04-1.25), respectively. Of survivors born in 24 to 26 gestational weeks, 29% had normal outcome.

CONCLUSION

As the majority of the extremely preterm born children had some problems, long-term follow-up is warranted to identify those with special needs and to design individual multidisciplinary support programs.

Neurological condition assessed with the Hempel examination and cognition and behaviour at 4years

AIM

To investigate associations between neurological condition, assessed with the Hempel examination, in terms of minor neurological dysfunction (MND) and neurological optimality, and cognition and behaviour at 4years.

STUDY DESIGN

Cross-sectional analyses within a prospective, assessor-blinded follow-up study.

SUBJECTS

Four-year-old singletons born to subfertile parents (n=235; 120 boys).

OUTCOME MEASURES

Outcome parameters were complex minor neurological dysfunction (complex MND) and the neurological optimality score (NOS). Cognitive outcome was evaluated with the Kaufman Assessment Battery for Children, resulting in a total intelligence quotient (IQ). Behavioural outcome was evaluated with the Child Behavior Checklist, resulting in a total problem T-score.

RESULTS

Fifty-seven (24.3%) children had complex MND. None of the children showed fine motor dysfunction, suggesting a ceiling effect of the Hempel assessment. Complex MND was not correlated with IQ or total problem T-score. Nevertheless, a higher NOS was correlated with a higher IQ and a lower total problem T-score (adjusted mean estimate [95% confidence interval]: cognition: 0.445 [0.026; 0.865], p=0.038; behaviour: -0.458 [-0.830; -0.087], p=0.016).

INTERPRETATION

At age 4, complex MND assessed with the Hempel assessment was not associated with cognition and behaviour, presumably due to a ceiling effect in the Hempel domain of fine motor function. A more optimal neurological condition was associated with higher IQ and better behaviour.

Minor neurological dysfunction in five year old very preterm children is associated with lower processing speed

BACKGROUND

Minor neurological dysfunction (MND) is present in one quarter to one third of children born very preterm (VP). The more severe form, complex (c)-MND has been associated with learning disabilities, behavioural and motor problems.

OBJECTIVE

To study the association between c-MND and neurocognitive and motor disabilities at age five in VP children without CP.

METHODS

Ninety-four children born with gestational age<30weeks and/or a birth weight<1000g were assessed at five years corrected age. MND was classified according to Touwen. The Wechsler Preschool and Primary School Scale of Intelligence (WPPSI-III-NL) was used to measure intelligence. Simple reaction time, focused attention and visuomotor coordination were measured using the Amsterdam Neuropsychological Tasks, and working memory using a Digit Span Task. For motor skills the Movement Assessment Battery for children (M-ABC2) was used.

RESULTS

Eighty-one percent was classified as 'normal' (no or simple (s-)-MND) and 19% as 'abnormal'(c-MND or mild CP). The abnormal group had a significantly lower processing speed quotient (PSQ), M-ABC percentile score and slower simple Reaction Time than the normal group. Verbal IQ, Performance IQ, working memory, focused attention and visuomotor coordination did not differ between groups. Exclusion of the mild CP cases (n=4) led to similar results.

CONCLUSIONS

Five year old VP children with c-MND have lower PSQ, slower reaction time, and poorer motor skills, than those without c-MND. Neurological examination should include identification of MND to help identify children at risk for neurocognitive disabilities.

Minor neurological dysfunction and behaviour in 9-year-old children born at term: evidence for sex dimorphism

AIM

The aim of the study was to assess associations between minor neurological dysfunction (MND) and behaviour, with specific attention to sex differences.

METHOD

This was an observational cohort study in which 341 9-year-old children (177 male, 164 female) without perinatal risk were neurologically assessed, with attention to severity and type of MND. Eight domains of dysfunction were distinguished, including posture and muscle tone, fine manipulative ability and coordination. Severity of MND was based on the number of dysfunctional domains. Behaviour was assessed by parents and teachers using the Child Behavior Checklist and Teacher's Report Form (TRF); outcomes were internalizing and externalizing behaviour and total score of behavioural problems.

RESULTS

Females with complex MND or dysfunctional posture and muscle tone had increased risk for externalizing behavioural problems (OR 4.52, 95% CI 1.01-20.2, and OR 4.05, 95% CI 1.06-15.5, respectively). In males, these associations were absent. However, males with simple MND had an increased risk for behavioural problems indicated by the total TRF-score (OR 7.52, 95% CI 1.36-41.4).

INTERPRETATION

In children without perinatal risk, associations between MND and behaviour are sex-specific. In females, dysfunction of complex neural networks, including the cerebellum, is associated with externalizing behaviour. In males, neurobehavioural relationships are limited, suggesting a larger role of psychosocial factors in the genesis of behavioural problems.

Minor neurological dysfunction and cognition in 9-year-olds born at term

BACKGROUND

In children with developmental disorders, motor problems often co-occur with cognitive difficulties. Associations between specific cognitive deficits underlying learning problems and minor neurological dysfunction (MND) are still unknown.

AIMS

To assess associations between specific types of MND as clinical markers of non-optimal brain function and performance in specific cognitive domains.

STUDY DESIGN

Part of a randomized controlled trial.

SUBJECTS

Three hundred and forty one 9-year-old children born at term (177 boys, 164 girls).

OUTCOME MEASURES

Children were neurologically assessed to detect eight types of MND: mild dysfunction in posture and muscle tone, reflexes, coordination, fine manipulative ability, sensory function, cranial nerve function, choreiform dyskinesia and excessive associated movements. Cognitive function in the domains of attention, memory and language was evaluated using the Test of Everyday Attention for Children (TEA-Ch), a developmental neuropsychological assessment (NEPSY) and the Children's Memory Scale.

RESULTS

Fine manipulative disability and coordination problems were associated with lower scores on attention, memory and learning and language, other types of MND were not. Girls with coordination problems performed significantly worse on attention/executive function than those without this dysfunction; however, in boys, such association was absent.

CONCLUSION

Particularly, fine manipulative disability and coordination problems were associated with worse cognitive function in the domains of attention, learning and memory and language. Previous and present data suggest a minor sex difference in neurocognitive associations: in girls dysfunction of the cerebello-thalamo-cortical pathways may be associated with cognitive deficits, while in boys cognitive impairment may be associated with dysfunction of cortico-striato-thalamo-cortical pathways.

Minor neurological dysfunction in children with autism spectrum disorder

AIM

The aim of this study was to improve the understanding of brain function in children with autism spectrum disorder (ASD) in relation to minor neurological dysfunctions (MNDs).

METHOD

We studied MNDs in 122 children (93 males, 29 females; mean age 8 y 1 mo, SD 2 y 6 mo) who, among a total cohort of 705 children (513 males, 192 females; mean age 9 y, SD 2 y 0.5 mo) referred to a regional outpatient non-academic psychiatric centre in the Netherlands, were diagnosed with ASD after an extensive multidisciplinary psychiatric assessment. Children with clear neurological abnormalities (e.g. cerebral palsy or spina bifida) were excluded from the study. MNDs were assessed in all 705 children using the Touwen examination method. Special attention was paid to the severity and type of MND. Data of the children with ASD were compared with neurological morbidity data of children with other psychiatric disorders and with children in the general population, who were born at Groningen University Hospital between 1975 and 1978.

RESULTS

Seventy-four percent of the children with ASD showed complex MNDs compared with 52% of the children with other psychiatric disorders and 6% of the reference group (χ(2) =18.0, p<0.001; χ(2) =937.5, p<0.001 respectively). Specific dysfunctions frequently encountered in ASD were dysfunctional posture and muscle tone, fine manipulative disability, dyscoordination, and excessive associated movements.

CONCLUSION

These findings suggest a contribution of dysfunctional supraspinal networks involving multiple parts of the brain in the pathogenesis of ASD. This is consistent with findings from neuroimaging studies, and highlights the importance of neurological examinations in paediatric psychiatric assessments.