Monday, July 14, 2008

Spatial cognition and motor development: a study of children with spina bifida.

Jansen-Osmann P, Wiedenbauer G, Heil M.
Spatial cognition and motor development: a study of children with spina bifida.
Perceptual and Motor Skills. 2008 Apr;106(2):436-46.

The purpose of this study was to examine the relation between motor development and spatial cognition. The sample was 20 children with Spina bifida (M age: 11.4 yr., SD = 1.7) and 20 healthy children as controls (M age: 11.8, SD = 1.8 yr.). An experimental assessment of motor development in spatial cognition in a simulated virtual maze by school-age children is lacking. In this study children with Spina bifida, who were impaired in walking since birth, completed four visuospatial tasks in a small-scale space (Mental Rotation, Water-Level Task, Embedded Figures Test, Visual Short-term Memory Test), and a spatial behaviour and knowledge task in a virtual maze. These children showed poorer performance than children in the control group on most measures. The results are discussed with respect to theoretical implications and further research.

PMID: 18556900

White matter microstructural abnormalities in children with spina bifida myelomeningocele and hydrocephalus: a diffusion tensor tractography study of

Hasan KM, Eluvathingal TJ, Kramer LA, Ewing-Cobbs L, Dennis M, Fletcher JM.
White matter microstructural abnormalities in children with spina bifida myelomeningocele and hydrocephalus: a diffusion tensor tractography study of the association pathways.
Journal of Magnetic Resonance Imaging: JMRI. 2008 Apr;27(4):700-9.

PURPOSE: To quantify microstructural abnormalities in the major association pathways of children affected by spina bifida myelomeningocele (SBM) and shunted hydrocephalus using whole-brain diffusion tensor imaging (DTI).

MATERIALS AND METHODS: The institutional review board approved this Health Insurance Portability and Accountability Act (HIPAA)-compliant study and written informed consent/assent were obtained prior to the study. The 69 participants included 38 children with SBM and shunted hydrocephalus (age mean +/- SD = 12.30 +/- 2.10 years; 22 boys; 10 left-handed) and 31 age- and sex-matched normally-developing children (11.56 +/- 2.72 years; 15 boys, four left-handed). Diffusion tensor tractography (DTT) was performed to delineate and quantify bilaterally four major association pathways (arcuate, inferior longitudinal, inferior fronto-occipital, and uncinate fasciculi).

RESULTS: The group with SBM did not exhibit the pattern of age-related decreases in the diffusivities observed in the controls. The transverse and axial diffusivities were significantly elevated in most of the white matter pathways of the participants with SBM. The fractional anisotropy (FA) was significantly lower in most of the association pathways. Many of the association pathways were not traceable in some participants with SBM compared to the controls at the selected FA thresholds.

CONCLUSION: DTT revealed diffusion tensor characteristics of abnormal development (nonvisualization/poor visualization of tracts, downward arrow FA, upward arrow diffusivities), impairment in myelination (upward arrow transverse diffusivity) as well as abnormalities in intrinsic axonal characteristics and extraaxonal/extracellular space (upward arrow axial diffusivity) in the association pathways of the SBM children. The differences in the diffusion metrics observed in the children with SBM are suggestive of abnormal white matter development and persistent degeneration with increased age. (c) 2008 Wiley-Liss, Inc.

PMID: 18302204

Quantitative diffusion tensor imaging and intellectual outcomes in spina bifida: laboratory investigation

Hasan KM, Sankar A, Halphen C, Kramer LA, Ewing-Cobbs L, Dennis M, Fletcher JM.
Quantitative diffusion tensor imaging and intellectual outcomes in spina bifida: laboratory investigation.
Journal of Neurosurgery: Pediatrics. 2008 Jul;2(1):75-82.

OBJECT: Patients with spina bifida (SB) have variable intellectual outcomes. The authors used diffusion tensor (DT) imaging to quantify whole-brain volumes of gray matter, white matter, and cerebrospinal fluid (CSF), and perform regional quantitative microstructural assessments of gray matter nuclei and white matter tracts in relation to intellectual outcomes in patients with SB.

METHODS: Twenty-nine children with myelomeningoceles and 20 age- and sex-matched children with normal neural tube development underwent MR imaging with DT image acquisition and assessments of intelligence. The DT imaging-derived metrics were the fractional anisotropy (FA), axial (parallel), and transverse (perpendicular) diffusivities. These metrics were also used to segment the brain into white matter, gray matter, and CSF. A region-of-interest analysis was conducted of the white and gray matter structures implicated in hydrocephalus.

RESULTS: The amount of whole-brain gray matter was decreased in patients with SB, with a corresponding increase in CSF (p < 0.0001). Regional transverse diffusivity in the caudate nucleus was decreased (p < 0.0001), and the corresponding FA was increased (p < 0.0001), suggesting reduced dendritic branching and connectivity. Fractional anisotropy in the posterior limb of the internal capsule increased in the myelomeningocele group (p = 0.02), suggesting elimination of some divergent fascicles; in contrast, the FA in several white matter structures (such as the corpus callosum genu [p < 0.001] and arcuate fasciculus) was reduced, suggesting disruption of myelination. Diffusion tensor imaging-metrics involving gray matter volume and the caudate nucleus, but not other structures, predicted variations in IQ (r = 0.37-0.50; p < 0.05).

CONCLUSIONS: Diffusion tensor imaging-derived metrics provide noninvasive neuronal surrogate markers of the pathogenesis of SB and predict variations in general intellectual outcomes in children with this condition.


PMID: 18590401

Muscle strength, aerobic capacity and physical activity in independent ambulating children with lumbosacral spina bifida.

Schoenmakers MA, de Groot JF, Gorter JW, Hillaert JL, Helders PJ, Takken T.
Muscle strength, aerobic capacity and physical activity in independent ambulating children with lumbosacral spina bifida.
Disability and Rehabilitation. 2008 May 21:1-8.

Purpose. This cross-sectional study investigates deficits and associations in muscle strength, 6-minute walking distance (6MWD), aerobic capacity (VO(2peak)), and physical activity (PA) in independent ambulatory children with lumbosacral spina bifida. Method. Twenty-tree children participated (13 boys, 10 girls). Mean age (SD): 10.4 (+/-3.1) years. Muscle strength (manual muscle testing and hand-held dynamometry), 6MWD, VO(2peak) (maximal exercise test on a treadmill), and PA (quantity and energy expenditure [EE]), were measured and compared with aged-matched reference values. Results. Strength of upper and lower extremity muscles, and VO(2peak) were significantly lower compared to reference values. Mean Z-scores ranged from -1.2 to -2.9 for muscle strength, and from -1.7 to -4.1 for VO2peak. EE ranged from 73 - 84% of predicted EE. 6MWD was significantly associated with muscle strength of hip abductors and foot dorsal flexors. VO(2peak) was significantly associated with strength of hip flexors, hip abductors, knee extensors, foot dorsal flexors, and calf muscles. Conclusions. These children have significantly reduced muscle strength, 6MWD, VO(2peak) and lower levels of PA, compared to reference values. VO(2peak) and 6MWD were significantly associated with muscle strength, especially with hip abductor and ankle muscles. Therefore, even in independent ambulating children training on endurance and muscle strength seems indicated.

PMID: 18608426

Limiting factors in peak oxygen uptake and the relationship with functional ambulation in ambulating children with Spina Bifida.

De Groot JF, Takken T, Schoenmakers MA, Vanhees L, Helders PJ.
Limiting factors in peak oxygen uptake and the relationship with functional ambulation in ambulating children with Spina Bifida.
European journal of applied physiology. 2008 Jul 10.

The objective of this study is to interpret the outcomes of peak oxygen uptake (VO(2peak)) in children with SB and explore the relationship between VO(2peak) and functional ambulation using retrospective cross-sectional study. Twenty-three ambulating children with SB participated at Wilhelmina's Children's Hospital Utrecht, the Netherlands. VO(2peak) was measured during a graded treadmill-test. Eschenbacher's and Maninna's algorithm was used to determine limiting factors in reaching low VO(2peak) values. Energy expenditure during locomotion (both O(2) rate and O(2) cost) and percentage of VO(2peak) and HR(peak) were determined during a 6-min walking test (6MWT). Differences between community and normal ambulators were analyzed. VO(2peak), VO(2peak)/kg, HR(peak), RER(peak) and VE (peak) were significantly lower compared to reference values, with significant differences between normal and community ambulators. Limiting factors according to the algorithm were mostly "muscular and/or deconditioning" (47%) and ventilatory "gasexchange" (35%). Distance walked during 6MWT was 48.5% of predicted distance. Both O(2) rate and O(2) cost were high with significant differences between normal and community ambulators [17.6 vs. 21.9 ml/(kg min) and 0.27 vs 0.43 ml/(kg m)]. Also %HR(peak) and %VO(2peak) were significantly higher in community ambulators when compared to normal ambulators (resp. 97.6 vs. 75% and 90.2 vs. 55.9%). VO(2peak) seems to be mostly limited by deconditioning and/or muscular components and possible ventilatory factors. For both peak values and functional ambulation, community ambulators were significantly more impaired than normal ambulators. High energy expenditure, %VO(2peak) and %HR(peak) reflect high level of strain during ambulation in the community ambulators. Future exercise testing in children with SB should include assessment of ventilatory reserve. Exercise training in ambulatory children should focus on increasing both VO(2peak) and muscular endurance, as well as decreasing energy cost of locomotion.


PMID: 18618132