Ross Hetherington

Functional outcome in young adults with spina bifida and hydrocephalus

IntroductionQuality of life was studied in 31 adult survivors of spina bifida, each with Verbal or Performance IQ score over 70.MethodsInstruments measured physical and occupational function, cognitive/psychological function, somatic sensation, and social interaction in the context of the ability to live independently.ResultsDomain group means except motor independence were in the average range (±1 standard deviation). Variability within the group with respect to physical phenotype (high spinal lesions were associated with poorer motor independence) and medical history [a greater number of shunt revisions (>4) were associated with poorer functional numeracy] was predictive of quality of life. Both spinal lesion level and number of shunt revisions influenced occupational status.DiscussionThere was a relation between everyday mathematics, reading skills, and quality of life. The consequences of the physical, medical, and cognitive effects of spina bifida extend into young adulthood and have an impact on quality of life.

Object-based and action-based visual perception in children with spina bifida and hydrocephalus

Children with spina bifida and hydrocephalus (SBH) have long been known to have difficulties with visual perception. We studied how children with SBH perform 12 visual perception tasks requiring object identification, multistable representations of visual space, or visually guided overt actions. Four tasks required object-based processing (visual constancy illusions, face recognition, recognition of fragmented objects, line orientation). Four tasks required the representation of visual space in egocentric coordinates (stereopsis, visual figure-ground identification, perception of multistable figures, egocentric mental rotation). Four tasks required the coupling of visual space to overt movement (visual pursuit, figure drawing, visually guided route finding, visually guided route planning). Effect sizes, measuring the magnitude of the difference between SBH children and controls, were consistently larger for action-based than object-based visual perception tasks. Within action-based tasks, effect sizes were large and roughly comparable for tasks requiring the representation of visual space and for tasks requiring visually guided action. The results are discussed in terms of the physical and brain problems of children with SBH that limit their ability to build effective situation models of space.

Motor function profile in children with early onset hydrocephalus

A test of motor development (McCarron, 1976) was administered to 42 children between the ages of 5 and 15 who had been diagnosed with hydrocephalus in the 1 st year of life and treated with the placement of a shunt. Four domains of motor function were assessed: (a) persistent motor control; (b) strength; (c) balance, gait, and posture; and (d) fine motor skills. As a group, these children were impaired on measures of balance, gait, and posture, and upper and lower extremity strength. Performance on measures of fine motor skills and persistent motor control were significantly below average. The motor function profile of the group of children with hydrocephalus resulting from myelomeningocele and aqueduct stenosis, etiologies with a congenital onset (n = 23), differed from that of the group of children with hydrocephalus resulting from intraventricular hemorrhage and infections or adhesions, etiologies with an infantile onset (n = 19). Although their individual contribution is yet to be established, handed‐...

Reading and writing skills in young adults with spina bifida and hydrocephalus.

Reading and writing were studied in 31 young adults with spina bifida and hydrocephalus (SBH). Like children with this condition, young adults with SBH had better word decoding than reading comprehension, and, compared to population means, had lower scores on a test of writing fluency. Reading comprehension was predicted by word decoding and listening comprehension. Writing was predicted by fine motor finger function, verbal intelligence, and short-term and working memory. These findings are consistent with cognitive models of reading and writing. Writing, but not reading, was related to highest level of education achieved and writing fluency predicted several aspects of functional independence. Reading comprehension and writing remain deficient in adults with SBH and have consequences for educational attainments and functional independence.

Perception and estimation of time in long-term survivors of childhood posterior fossa tumors

We examined short duration perception (400 ms), long duration estimation (30 and 60 min), and spatiotemporal estimation in long-term survivors of childhood cerebellar tumors with a mean time since diagnosis of 14.2 years. Groups of individuals with tumors treated with surgery only (astrocytoma, N = 20) were compared to those with tumors treated with surgery, focal radiation, and craniospinal radiation (medulloblastoma, N = 20), and to age-matched controls (N = 40). Childhood lesions of the cerebellum produced enduring deficits in short-duration perception, but spared the ability to functionally estimate long durations, regardless of the pathology or treatment of the tumor. Evidence did not support any functional recovery over time of the cerebellar system that underlies short-duration perception. Younger age at treatment was not a protective factor. Although no group differences were present in the functional measures of long-duration estimation, tumor-related prospective memory deficits interfered with the ability to produce long-duration prospective estimates. The utilization of sensory and somatomotor information to refine real-world spatiotemporal estimates was compromised in the medulloblastoma group only.

Short-term intellectual outcome after arterial ischemic stroke and sinovenous thrombosis in childhood and infancy.

Arterial ischemic stroke is approximately four times more prevalent than sinovenous thrombosis and has been associated with a worse neurologic outcome than sinovenous thrombosis; however, no data are available comparing intellectual outcome after pediatric arterial ischemic stroke and sinovenous thrombosis. We report the short-term intellectual outcome (mean 5.8 months since stroke) in a sample of 72 children, 47 with arterial ischemic stroke, and 25 with sinovenous thombosis. Intellectual outcome measures were the Full-Scale IQ of the age-appropriate Wechsler intelligence test for older children and the Mental Developmental Index of the Bayley Scales of Infant Development for younger children. Stroke type did not directly influence intellectual outcome. Intellectual outcome was in the normal range whether the children had suffered an arterial ischemic stroke or a sinovenous thrombosis. (J Child Neurol 2005;20:553—559).

Motor learning in children with spina bifida: Dissociation between performance level and acquisition rate

The cerebellum is part of a neural circuit involved in procedural motor learning. We examined how congenital cerebellar malformations affect mirror drawing performance, a procedural learning task that involves learning to trace the outline of a star while looking at the reflection of the star in a mirror. Participants were 88 children with spina bifida myelomeningocele, a neural tube defect that results in lesions of the spinal cord, dysmorphology of the cerebellum, and requires shunt treatment for hydrocephalus, and 35 typically developing controls. Participants completed 10 trials in the morning and 10 trials following a 3-hr delay. Although children with spina bifida myelomeningocele were initially slower at tracing and made more errors than controls, all participants improved their performance of the task, as demonstrated by increased speed and accuracy across trials. Moreover, degree of cerebellar dysmorphology was not correlated with level of performance, rate of acquisition, or retention of mirror drawing. The results suggest that congenital cerebellar dysmorphology in spina bifida does not impair motor skill learning as measured by acquisition and retention of the mirror drawing task.

Space-based inhibition of return in children with spina bifida

Inhibition of return (IOR) refers to an increase in time to react to a target in a previously attended location. Children with spina bifida meningomyelocele (SBM) and hydrocephalus have congenital dysmorphology of the midbrain, a brain region associated with the control of covert orienting in general and with IOR in particular. The authors studied exogenously cued covert orienting in 8- to 19-year-old children and adolescents (84 with SBM and 37 age-matched, typically developing controls). The exogenous cue was a luminance change in a peripheral box that was 50% valid for the upcoming target location. Compared with controls, children with SBM showed attenuated IOR in the vertical plane, a deficit that was associated with midbrain dysmorphology in the form of tectal beaking but not with posterior brain volume loss. The data add to the emerging evidence for SBM deficits in attentional orienting to salient information.

Motor learning in children with spina bifida: intact learning and performance on a ballistic task.

Learning and performance on a ballistic task were investigated in children with spina bifida meningomyelocele (SBM), with either upper level spinal lesions (n = 21) or lower level spinal lesions (n = 81), and in typically developing controls (n = 35). Participants completed three phases (20 trials each) of an elbow goniometer task that required a ballistic arm movement to move a cursor to one of two target positions on a screen, including (1) an initial learning phase, (2) an adaptation phase with a gain change such that recalibration of the ballistic arm movement was required, and (3) a learning reactivation phase under the original gain condition. Initial error rate, asymptotic error rate, and learning rate did not differ significantly between the SBM and control groups. Relative to controls, the SBM group had reduced volumes in the cerebellar hemispheres and pericallosal gray matter (the region including the basal ganglia), although only the pericallosal gray matter was significantly correlated with motor adaptation. Congenital cerebellar dysmorphology is associated with preserved motor skill learning on voluntary, nonreflexive tasks in children with SBM, in whom the relative roles of the cerebellum and basal ganglia may differ from those in the adult brain.

Prospective, declarative, and nondeclarative memory in young adults with spina bifida.

The consequences of congenital brain disorders for adult cognitive function are poorly understood. We studied different forms of memory in 29 young adults with spina bifida meningomyelocele (SBM), a common and severely disabling neural tube defect. Nondeclarative and semantic memory functions were intact. Working memory was intact with low maintenance and manipulation requirements, but impaired on tasks demanding high information maintenance or manipulation load. Prospective memory for intentions to be executed in the future was impaired. Immediate and delayed episodic memory were poor. Memory deficits were exacerbated by an increased number of lifetime shunt revisions, a marker for unstable hydrocephalus. Memory status was positively correlated with functional independence, an important component of quality of life.