Olga Laporta-Hoyos

Measuring intellectual ability in cerebral palsy: The comparison of three tests and their neuroimaging correlates.

Standard intelligence scales require both verbal and manipulative responses, making it difficult to use in cerebral palsy and leading to underestimate their actual performance. This study aims to compare three intelligence tests suitable for the heterogeneity of cerebral palsy in order to identify which one(s) could be more appropriate to use. Forty-four subjects with bilateral dyskinetic cerebral palsy (26 male, mean age 23 years) conducted the Ravens Coloured Progressive Matrices (RCPM), the Peabody Picture Vocabulary Test-3rd (PPVT-III) and the Wechsler Nonverbal Scale of Ability (WNV). Furthermore, a comprehensive neuropsychological battery and magnetic resonance imaging were assessed. The results show that PPVT-III gives limited information on cognitive performance and brain correlates, getting lower intelligence quotient scores. The WNV provides similar outcomes as RCPM, but cases with severe motor impairment were unable to perform it. Finally, the RCPM gives more comprehensive information on cognitive performance, comprising not only visual but also verbal functions. It is also sensitive to the structural state of the brain, being related to basal ganglia, thalamus and white matter areas such as superior longitudinal fasciculus. So, the RCPM may be considered a standardized easy-to-administer tool with great potential in both clinical and research fields of bilateral cerebral palsy.

White matter integrity in dyskinetic cerebral palsy: Relationship with intelligence quotient and executive function

Background Dyskinetic cerebral palsy (CP) is one of the most disabling motor types of CP and has been classically associated with injury to the basal ganglia and thalamus. Although cognitive dysfunction is common in CP, there is a paucity of published quantitative analyses investigating the relationship between white matter (WM) microstructure and cognition in this CP type. Aims This study aims (1) to compare brain WM microstructure between people with dyskinetic CP and healthy controls, (2) to identify brain regions where WM microstructure is related to intelligence and (3) to identify brain regions where WM microstructure is related to executive function in people with dyskinetic CP and (4) to identify brain regions where the correlations are different between controls and people with CP in IQ and executive functions. Patients and methods Thirty-three participants with dyskinetic CP (mean ± SD age: 24.42 ± 12.61, 15 female) were age and sex matched with 33 controls. Participants underwent a comprehensive neuropsychological battery to assess intelligence quotient (IQ) and four executive function domains (attentional control, cognitive flexibility, goal setting and information processing). Diffusion weighted MRI scans were acquired at 3T. Voxel-based whole brain groupwise analyses were used to compare fractional anisotropy (FA) and of the CP group to the matched controls using a general lineal model. Further general linear models were used to identify regions where white matter FA correlated with IQ and each of the executive function domains. Results White matter FA was significantly reduced in the CP group in all cerebral lobes, predominantly in regions connected with the parietal and to a lesser extent the temporal lobes. There was no significant correlation between IQ or any of the four executive function domains and WM microstructure in the control group. In participants with CP, lower IQ was associated with lower FA in all cerebral lobes, predominantly in locations that also showed reduced FA compared to controls. Attentional control, goal setting and information processing did not correlate with WM microstructure in the CP group. Cognitive flexibility was associated with FA in regions known to contain connections with the frontal lobe (such as the superior longitudinal fasciculus and cingulum) as well as regions not known to contain tracts directly connected with the frontal lobe (such as the posterior corona radiata, posterior thalamic radiation, retrolenticular part of internal capsule, tapetum, body and splenium of corpus callosum). Conclusion The widespread loss in the integrity of WM tissue is mainly located in the parietal lobe and related to IQ in dyskinetic CP. Unexpectedly, executive functions are only related with WM microstructure in regions containing fronto-cortical and posterior cortico-subcortical pathways, and not being specifically related to the state of fronto-striatal pathways which might be due to brain reorganization. Further studies of this nature may improve our understanding of the neurobiological bases of cognitive impairments after early brain insult.

Whole-brain structural connectivity in dyskinetic cerebral palsy and its association with motor and cognitive function

Dyskinetic cerebral palsy (CP) has long been associated with basal ganglia and thalamus lesions. Recent evidence further points at white matter (WM) damage. This study aims to identify altered WM pathways in dyskinetic CP from a standardized, connectome‐based approach, and to assess structure‐function relationship in WM pathways for clinical outcomes. Individual connectome maps of 25 subjects with dyskinetic CP and 24 healthy controls were obtained combining a structural parcellation scheme with whole‐brain deterministic tractography. Graph theoretical metrics and the network‐based statistic were applied to compare groups and to correlate WM state with motor and cognitive performance. Results showed a widespread reduction of WM volume in CP subjects compared to controls and a more localized decrease in degree (number of links per node) and fractional anisotropy (FA), comprising parieto‐occipital regions and the hippocampus. However, supramarginal gyrus showed a significantly higher degree. At the network level, CP subjects showed a bilateral pathway with reduced FA, comprising sensorimotor, intraparietal and fronto‐parietal connections. Gross and fine motor functions correlated with FA in a pathway comprising the sensorimotor system, but gross motor also correlated with prefrontal, temporal and occipital connections. Intelligence correlated with FA in a network with fronto‐striatal and parieto‐frontal connections, and visuoperception was related to right occipital connections. These findings demonstrate a disruption in structural brain connectivity in dyskinetic CP, revealing general involvement of posterior brain regions with relative preservation of prefrontal areas. We identified pathways in which WM integrity is related to clinical features, including but not limited to the sensorimotor system. Hum Brain Mapp 38:4594–4612, 2017.

Does Verbal and Gestural Expression Ability Predict Comprehension Ability in Cerebral Palsy

Some people with cerebral palsy have motor and associated impairments that may hinder verbal and gestural expression to various extents. This study explores whether the ability to produce verbal or gestural expressions may be related to the comprehension of verbal communications and gestures. The influence of severity of motor impairment, general cognitive performance, and age on comprehension ability was also explored. Forty people with cerebral palsy were assigned to different groups according to their verbal and gestural expression abilities. A neuropsychological assessment of comprehension abilities and general cognitive performance was carried out. Multiple linear regression analysis was applied to identify the possible influence of expression abilities on comprehension abilities and also to detect the possible contribution of severity of motor impairment, general cognitive performance, and age. Results indicate that verbal and gestural comprehension was mainly predicted by general cognitive performance. Severity of motor impairment and age did not contribute to predicting comprehension abilities. Only verbal grammar comprehension was significantly predicted by verbal expression ability. Verbal expression ability may be an important marker for cerebral palsy therapies. In non-ambulant patients with bilateral cerebral palsy, impaired gestural expression should not be taken as an indicator of impaired gestural comprehension.

Brain lesion scores obtained using a simple semi-quantitative scale from MR imaging are associated with motor function, communication and cognition in dyskinetic cerebral palsy

Purpose To characterise brain lesions in dyskinetic cerebral palsy (DCP) using the semi-quantitative scale for structural MRI (sqMRI) and to investigate their relationship with motor, communication and cognitive function. Materials and methods Thirty-nine participants (19 females, median age 21y) with DCP were assessed in terms of motor function, communication and a variety of cognitive domains. Whole-head magnetic resonance imaging (MRI) was performed including T1-MPRAGE, T2 turbo spin echo (axial plane), and fluid attenuated inversion recovery images (FLAIR). A child neurologist visually assessed images for brain lesions and scored these using the sqMRI. Ordinal, Poisson and binomial negative regression models identified which brain lesions accounted for clinical outcomes. Results Brain lesions were most frequently located in the ventral posterior lateral thalamus and the frontal lobe. Gross (B = 0.180, p < .001; B = 0.658, p < .001) and fine (B = 0.136, p = .003; B = 0.540, p < .001) motor function were associated with global sqMRI score and parietal involvement. Communication functioning was associated with putamen involvement (B = 0.747, p < .028). Intellectual functioning was associated with global sqMRI score and posterior thalamus involvement (B = −0.018, p < .001; B = −0.192, p < .001). Selective attention was associated with global sqMRI score (B = −0.035, p < .001), parietal (B = −0.063, p = .023), and corpus callosum involvement (B = −0.448, p < .001). Visuospatial and visuoperceptive abilities were associated with global sqMRI score (B = −0.078, p = .007) and medial dorsal thalamus involvement (B = −0.139, p < .012), respectively. Conclusions Key clinical outcomes in DCP are associated with specific observable brain lesions as indexed by a simple lesion scoring system that relies only on standard clinical MRI.

White matter properties and reading in children born preterm: a step forward

Preterm birth seems to be increasing, with an estimated prevalence of 11% of all live births worldwide in 2010. Importantly, 31% of children born preterm present lifelong neurodevelopmental effects. Executive function and language/learning difficulties are common sequelae of preterm birth, and are associated with increased health care costs and educational needs. Reading skills are essential for educational progress, as they are the gateway to academic achievement and general knowledge. Together with previous work, the diffusion magnetic resonance study by Dodson et al. advances our understanding of the neural basis of this key learning difficulty in children born preterm. Firstly, their findings suggest that phonological awareness is similar in children born at term and preterm at the early stages of learning to read, and that in both groups this ability is supported by dorsal tracts. In view of their results, it would be interesting to explore the association between phonological awareness and white matter microstructure in tracts other than the left-hemisphere arcuate fasciculus in participants born preterm. Positive results might indicate the contribution of compensatory mechanisms that bring the performance of children born preterm up to the level of participants born at term. To address these questions, the use of a whole brain approach that does not require a priori selection of tracts of interest might provide new insights. Secondly, the authors report an association (which is moderated by prematurity) between fractional anisotropy of the right uncinate fasciculus and receptive and expressive language. Interestingly, the authors posit that the lack of association in their preterm sample might be because the uncinate fasciculus myelates late and is slow to develop. Given that participants were in the early stages of learning to read, it would be interesting to monitor their reading acquisition and its neural correlate to check this hypothesis. Additionally, to further understand the origin of reading difficulties in children born preterm and their neural basis, the results should be interpreted in light of studies reporting delayed event-related potentials and mismatch negativity responses to speech sounds in 3-month old children born preterm. It has been suggested that these measures can be used for the early identification of the risk of language impairment. One strength of this study is that both fractional anisotropy and mean diffusivity results are reported. These measures are related but different, and so reporting both gives a fuller picture of the neural bases underlying pre-reading skills. Another important strength is that results are controlled for non-verbal intellectual abilities. It might be argued, however, that the basic neuropsychological processes that have been reported to be impaired in children born preterm, such as visual perception and attention, may underlie reading difficulties as well. In particular, accurate signalling of shifts of attention by the visual system seem to be a key ability underlying reading performance. Thus, the fact that these functions were not directly assessed may represent a limitation. Overall, the study provides novel insights into the similarities and differences of the neurobiology of pre-reading skills in children born preterm and at term. These insights help to explain the previously reported variations observed by this research group in the neurobiology of reading in older participants born at term and preterm. Future studies including children born moderate/late preterm are also warranted as this seems to be the most frequent type of prematurity. Finally, we strongly encourage: further research with larger samples; an exploration into the effects of being a pre-reader/reader; the use of a whole brain approach; and ideally a longitudinal follow-up. The information provided by these studies could be used to assist reading acquisition in children born preterm.

O-073 Total And Regional Corpus Callosum Volumes Are Related To Intelligence And Motor Function In Dyskinetic Cerebral Palsy

Background The relationship between corpus callosum (CC) morphology and mainly motor outcomes has been studied in spastic cerebral palsy (CP) but not yet in dyskinetic CP, which has been recently related to a diffuse brain injury pattern. This study aims to analyse the relationship of total and regional CC volumes with intelligence and motor impairment severity in dyskinetic CP. Methods 15 subjects (age range, 12–34) with dyskinetic CP and signs of perinatal asphyxia underwent a MRI. CC total, anterior, central and posterior volumes were calculated (Figure 1). The intelligence and motor scales most commonly used in CP were administered. Abstract O-073 Figure 1 CC subdivisions generated by Freesurfer (in colour) Results The CC total volume and most of its parts were related to intelligence and motor measures (Table 1). Abstract O-073 Table 1 Partial correlation controlling for age Intelligence Motor Verbal1 Non-verbal2 GMFCS BFMF MACS TOTAL CC 0.773*** 0.775*** -0.641** -0.542* -0.634** ANTERIOR 0.612** 0.681** no significative CENTRAL 0.659** 0.637 ** -0.619** -0.587* -0.641** POSTERIOR 0.812*** 0.779*** -0.684** -0.517* -0.656** * <.05; ** <. 01; *** <. 001; GMFCS: Gross Motor Function Classification System; BFMF: Bimanual Fine Motor Function; MACS: Manual Ability Classification System; 1Peabody Picture Vocabulary Test-3rd; 2Raven’s Progressive Matrices. Conclusions Total CC volume may be indicative of intelligence and motor status in dyskinetic CP. Regionally, the posterior part is the most related to intelligence, in agreement with recent theories of intelligence. The anterior part of the CC is not found to be related to motor function. This result agrees with the fact that premotor and sensorimotor fibres are located more posteriorly than previously thought.