Cognitive profile in young adults born preterm at very low birthweight

Aim The aim of this study was to assess cognitive function at the age of 19 years in individuals of very low birthweight (VLBW; ≤1500g) and in term‐born comparison individuals. Method In this hospital‐based follow‐up study, 55 VLBW participants (30 males, 25 females; mean birthweight 1217g, SD 233g; mean gestational age 29.1wks, SD 2.5wks) and 81 comparison individuals (42 males, 39 females; mean birthweight 3707g, SD 433g; mean gestational age 39.7wks, SD 1.2wks) were examined with a standardized IQ test (Wechsler Adult Intelligence Scale III) to assess general cognitive ability. Results Over half (53%) of the VLBW participants achieved a low IQ score (defined as >1SD below the mean in the comparison group; odds ratio 6.4 vs comparison individuals; 95% confidence interval 2.8–14.4; p<0.001). None of the VLBW group, compared with 22% of the comparison individuals, achieved a high IQ score (>1SD above the comparison mean). VLBW participants scored lower than comparison individuals on full, verbal, and performance IQ, as well as on all four indices (p≤0.001). The subtest profile indicated problems on all subtests, but especially on those related to arithmetic and visual–perceptual tasks. Interpretations Few studies have undertaken a comprehensive assessment of general cognitive outcome (IQ) among young adults of VLBW. Our results indicate that VLBW seems to have a global and lasting impact on cognitive ability. Full‐scale IQ assessment may reveal important learning problems in young adults of VLBW, and should be performed to inform appropriate assistance to enhance academic achievement and the chances of permanent employment as adults.     

Stuttering as a trait or state – an ALE meta‐analysis of neuroimaging studies

Stuttering is a speech disorder characterised by repetitions, prolongations and blocks that disrupt the forward movement of speech. An earlier meta‐analysis of brain imaging studies of stuttering (Brown et al., 2005) revealed a general trend towards rightward lateralization of brain activations and hyperactivity in the larynx motor cortex bilaterally. The present study sought not only to update that meta‐analysis with recent work but to introduce an important distinction not present in the first study, namely the difference between ‘trait’ and ‘state’ stuttering. The analysis of trait stuttering compares people who stutter (PWS) with people who do not stutter when behaviour is controlled for, i.e., when speech is fluent in both groups. In contrast, the analysis of state stuttering examines PWS during episodes of stuttered speech compared with episodes of fluent speech. Seventeen studies were analysed using activation likelihood estimation. Trait stuttering was characterised by the well‐known rightward shift in lateralization for language and speech areas. State stuttering revealed a more diverse pattern. Abnormal activation of larynx and lip motor cortex was common to the two analyses. State stuttering was associated with overactivation in the right hemisphere larynx and lip motor cortex. Trait stuttering was associated with overactivation of lip motor cortex in the right hemisphere but underactivation of larynx motor cortex in the left hemisphere. These results support a large literature highlighting laryngeal and lip involvement in the symptomatology of stuttering, and disambiguate two possible sources of activation in neuroimaging studies of persistent developmental stuttering.     

White matter alterations of the corticospinal tract in adults born very preterm and/or with very low birth weight

White matter (WM) injury, either visible on conventional magnetic resonance images (MRI) or measurable by diffusion tensor imaging (DTI), is frequent in preterm born individuals and often affects the corticospinal tract (CST). The relation between visible and invisible white mater alterations in the reconstructed CST of preterm subjects has so far been studied in infants, children and up to adolescence. Therefore, we probabilistically tracked the CST in 53 term‐born and 56 very preterm and/or low birth weight (VP/VLBW, < 32 weeks of gestation and/or birth weight < 1,500 g) adults (mean age 26 years) and compared their DTI parameters (axial, radial, mean diffusivity—AD, RD, MD, fractional anisotropy—FA) in the whole CST and slice‐wise along the CST. Additionally, we used the automatic, tract‐based‐spatial‐statistics (TBSS) as an alternative to tractography. We compared control and VP/VLBW and subgroups with and without CST WM lesions visible on conventional MRI. Compared to controls, VP/VLBW subjects had significantly higher diffusivity (AD, RD, MD) in the whole CST, slice‐wise along the CST, and in multiple regions along the TBSS skeleton. VP/VLBW subjects also had significantly lower (TBSS) and higher (tractography) FA in regions along the CST, but no different mean FA in the tracked CST as a whole. Diffusion changes were weaker, but remained significant for both, tractography and TBSS, when excluding subjects with visible CST lesions. Chronic CST injury persists in VP/VLBW adults even in the absence of visible WM lesions, indicating long‐term structural WM changes induced by premature birth. Hum Brain Mapp 37:289–299, 2016. © 2015 Wiley Periodicals, Inc.     

Hyperactivity in adolescents born very preterm is associated with decreased caudate volume.

BACKGROUND: Several studies have associated preterm birth with impaired behavioral functioning and attention problems. In addition, preterm individuals have an increased risk of brain injury in the neonatal period. Such early lesions have the potential to disrupt subsequent neurodevelopment. This study explored behavioral functioning, particularly externalizing behavior, in a group of adolescents who were born very preterm and its relationship with volume of the caudate, a brain region particularly vulnerable to damage in the preterm neonate. METHODS: We studied 72 adolescents born before 33 weeks and 50 age- and gender-matched full-term control subjects. Behavioral assessment included the Rutter Behavioural Scale and a social adjustment scale. Bilateral caudate volumes were quantified by stereologic methods. RESULTS: Preterm adolescents scored significantly higher than control subjects on the Rutter hyperactivity score, and boys scored higher than girls. In preterm boys only, left caudate volume was negatively correlated with hyperactivity score (r = -.43, p = .018) and social adjustment score in childhood (r = -.40, p = .028). CONCLUSIONS: Our data suggest that boys born very preterm are more likely to experience nonclinical behavioral problems in adolescence compared with full-term control subjects. Our results indicate that behavioral problems in this group might be associated with reductions in volume of the left caudate nucleus.     

Vermis and lateral lobes of the cerebellum in adolescents born very preterm

Adolescents born before 33 weeks' gestation have reduced cerebellar volume compared with term-born controls, and this is related to their cognitive performance. We wished to determine whether this relationship is regionally specific. We measured midline and lateral cerebellar volumes in magnetic resonance imaging scans from 67 very preterm adolescents and 50 term-born controls at 14-15 years. Volumes of vermis and lateral lobes were reduced in the preterm group, after controlling for whole-brain volume. Lateral cerebellar volume decrease was associated with reduced cerebral white matter volume, and with reduced executive, visuo-spatial and language function. Vermis volume was less strongly related to cognitive function. Volume decrement of the lateral lobes, rather than the vermis, is associated with neuropsychological dysfunction in very preterm individuals.     

Seizures in patients with Alzheimer’s disease or vascular dementia: A population‐based nested case–control analysis

Purpose: Patients with Alzheimer’s disease (AD) have an increased risk of developing seizures or epilepsy. Little is known about the role of risk factors and about the risk of developing seizures/epilepsy in patients with vascular dementia (VD). The aim of this study was to assess incidence rates (IRs) of seizures/epilepsy in patients with AD, VD, or without dementia, and to identify potential risk factors of seizures or epilepsy. Methods: We conducted a follow‐up study with a nested case–control analysis using the United Kingdom–based General Practice Research Database (GPRD). We identified patients aged ≥65 years with an incident diagnosis of AD or VD between 1998 and 2008 and a matched comparison group of dementia‐free patients. Conditional logistic regression was used to estimate the odds ratio (OR) with a 95% confidence interval (CI) of developing seizures/epilepsy in patients with AD or VD, stratified by age at onset and duration of dementia as well as by use of antidementia drugs. Key Findings: Among 7,086 cases with AD, 4,438 with VD, and 11,524 matched dementia‐free patients, we identified 180 cases with an incident diagnosis of seizures/epilepsy. The IRs of epilepsy/seizures for patients with AD or VD were 5.6/1,000 person‐years (py) (95% CI 4.6–6.9) and 7.5/1,000 py (95% CI 5.7–9.7), respectively, and 0.8/1,000 py (95% CI 0.6–1.1) in the dementia‐free group. In the nested case–control analysis, patients with longer standing (≥3 years) AD had a slightly higher risk of developing seizures or epilepsy than those with a shorter disease duration, whereas in patients with VD the contrary was observed. Significance: Seizures or epilepsy were substantially more common in patients with AD and VD than in dementia‐free patients. The role of disease duration as a risk factor for seizures/epilepsy seems to differ between AD and VD.     

Cerebral palsy among children born moderately preterm or at moderately low birthweight between 1980 and 1998: a European register-based study

Aim The aim of this study was to describe trends in prevalence, subtypes, and severity among children with cerebral palsy (CP) born moderately preterm (MPT; (gestational age 32–36wks) or at moderately low birthweight (MLBW; 1500–2499g) in Europe. Method We conducted trend analyses of data from 903 children with CP born between 1980 and 1998 who were MPT (gestational age 32–36wks), taken from 11 registers in the Surveillance of Cerebral Palsy in Europe database and from 1835 children with CP who were born at moderately low birthweight (1500–2499g), taken from 14 registers in the Surveillance of Cerebral Palsy in Europe database. Results The overall annual prevalence of CP in children born MPT varied between 12.2 (95% confidence interval [CI] 8.5–17.1) per 1000 live births in 1983 and 4.5 (95% CI 3.2–6.3) per 1000 in 1997. There was a significant decrease in the prevalence over time adjusted for register, with an annual change in prevalence of −3% (95% CI −5 to −2%). This was due to a decrease in the prevalence of bilateral spastic CP (annual change −5%; 95% CI −7 to −3%). Interpretation There was a trend towards a decrease in the prevalence of CP among children born MPT, but no difference in prevalence among children born at MLBW. Both results may represent an improvement in perinatal and neonatal care.