Prospective memory in adults with spina bifida.

INTRODUCTION: Individuals with neurodevelopmental disorders have been observed to show accelerated cognitive aging or even dementia as early as 30 and 40 years of age. Memory deficits are an important component of age-related cognitive loss. METHODS: In this study, we investigated prospective memory, which is often impaired in aging, in a group of 32 adults with spina bifida meningomyelocele (SBM), including members of the oldest living cohort successfully treated with shunts to divert excess cerebrospinal fluid, ventriculomegaly, and hydrocephalus, who are now around 50 years of age. Seventeen typically developing adults provided a comparison group. RESULTS: The SBM and comparison groups differed in the prospective memory total score as well as in both time-based and event-based subscores. Prospective memory was impaired in both older and younger individuals with SBM. However, the percentage of individuals with impaired or poor prospective memory was three times higher in the older SBM group than in the younger SBM group. The results are considered in relation to specific features of the complex brain reorganization in SBM.

Upper limb cerebellar motor function in children with spina bifida.

PURPOSE: To investigate upper limb cerebellar motor function in children with spina bifida myelomeningocele (SBM) and in typically developing controls. METHODS: Participants with SBM, who had either upper level spinal lesions (n = 23) or lower level spinal lesions (n = 65), and controls (n = 37) completed four upper limb motor function tasks (posture, rebound, limb dysmetria, and diadochokinesis) under four different physical and cognitive challenge conditions. Functional independence was assessed by parental questionnaire. RESULTS: Fewer SBM participants were able to complete the posture task, and they were less likely than controls to obtain a perfect rebound score. Participants with SBM showed impaired performance in either time, accuracy, or both, on the limb dysmetria and diadochokinesis tasks but responded like controls to physical and cognitive challenges. CONCLUSIONS: Because upper limb motor performance predicted aspects of functional independence, we conclude that upper limb impairments in children with SBM are significant and have direct implications for the level of independent functioning in children with SBM.

Verb generation in children with spina bifida.

We investigated verb generation in children with spina bifida meningomyelocele (SBM; n = 55) and in typically developing controls (n = 32). Participants completed 6 blocks (40 trials each) of a task requiring them to produce a semantically related verb in response to a target noun and an additional 40 trials on which they were simply required to read target nouns aloud. After controlling for reading response time, groups did not differ significantly in verb generation response time or learning. Children with SBM produced more non-verb errors than controls and tended to repeat their mistakes over blocks. Verb generation performance was associated with brain volume measures in participants with SBM. Congenital cerebellar dysmorphology is associated with impaired performance in verb generation accuracy, although not with increased response times to produce verbs

Infants' visual-proprioceptive intermodal perception with imperfect contingency information.

Two experiments explored 5-month-old infants' recognition of self-movement in the context of imperfect contingencies between felt and seen movement. Previous work has shown that infants can discriminate a display of another child's movements from an on-line video display of their own movements, even when featural information is removed. These earlier findings were extended by demonstrating self versus other discrimination when the visual information for movement was an unrelated object (a fluorescent mobile) directly attached to the child's leg, thus producing imperfect spatial and temporal contingency information. In contrast, intermodal recognition failed when the mobile was indirectly attached to infants' legs, thus eliminating spatial contingencies altogether and further weakening temporal contingencies. Together, these studies reveal that even imperfect contingency information can drive intermodal perception, given appropriate levels of spatial and temporal contingency information.

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.

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.