Hydrocephalic Group Research Articles

Quantitative follow-up analysis by computed tomographic imaging in neonatal hydrocephalus

We sought a simple and accurate method to monitor neonatal hydrocephalic infants using standard computed tomographic scans. Volume measurements were made by means of pixel counting using a personal computer and a drawing device, as a graphic tablet system, over computed tomographic scans of six infants with neonatal hydrocephalus and four age-matched control infants. The mean value (763.9 ± 83.3 cm 3) of the volume of the cranium in the hydrocephalic group was two times higher than that in the age-matched control infants (360.4 ± 41.4 cm 3), P < 0.00001. Sequential changes of the ventricular/intracranial volume ratio steadily decreased after cerebrospinal fluid diversion by means of a “two-step procedure” as early in postnatal life as feasible. The mean value (0.67 ± 0.12) of the lateral ventricle/intracranial volume ratio at birth improved to 12 months of age (0.26 ± 0.14), P < 0.05. This study has documented, by means of quantitative analysis of serial scans, a statistically significant increase in the neonatal hydrocephalic brain volume after cerebrospinal fluid shunting.

Impaired Motor Learning in Children with Hydrocephalus

Hydrocephalic (n = 19) and normal (n = 20) children in two age groups (averaged at 10 and 14 years old) were asked to learn 5 predetermined timing rhythm interval tasks (including timing duration and relative timing pattern) by pressing keys on a computer keyboard. In the acquisition phase, visual and auditory goal timing intervals, as well as visualized feedback were presented to all participants before and after their key presses, respectively. A retention test without the auditory information and visualized feedback was administered 1 day later. By using the computerized timing test, we demonstrated in this study that the hydrocephalic group had significantly (ANOVA analysis) increased relative timing errors; this function depends on the formation of an internal model or a motor program related to long-term memory disorders. These findings could lead to the formulation of training procedures with simplified movements that may help hydrocephalic children improve their motor skill learning.

Posttraumatic ventriculomegaly: hydrocephalus or atrophy? A new approach for diagnosis using CSF dynamics.

Cerebrospinal fluid (CSF) dynamics were correlated to the changes in ventricular size during the first 3 months posttrauma in patients with severe head injury (Glasgow Coma Scale score < or = 8, 75 patients) to distinguish between atrophy and hydrocephalus as the two possible causes of posttraumatic ventriculomegaly. Using the bolus injection technique, the baseline intracranial pressure (ICP), pressure volume index, and resistance for CSF absorption (R0) provided a three-dimensional profile of CSF dynamics that was correlated with ventricular size and Glasgow Outcome Scale (GOS) score at 3, 6, and 12 months posttrauma. Patients were separated into five different groups based on changes in ventricular size, presence of atrophy, and CSF dynamics. Group 1 (normal group, 41.3%) demonstrated normal ventricular size and normal ICP. Group 2 (benign intracranial hypertension group, 14.7%) showed normal ventricular size and elevated ICP. Group 3 (atrophy group, 24%) displayed ventriculomegaly, normal ICP, and normal R0. Group 4 (normal-pressure hydrocephalus group, 9.3%) had ventriculomegaly, normal ICP, and high R0. Group 5 (high-pressure hydrocephalus group, 10.7%) showed ventriculomegaly and elevated ICP with or without high R0. The GOS score in the nonhydrocephalic groups (Groups 1, 2, and 3) was better than in the hydrocephalic groups (Groups 4 and 5). It is concluded from these results that 44% of head injury survivors may develop posttraumatic ventriculomegaly. Posttraumatic hydrocephalus, as identified by abnormal CSF dynamics, was diagnosed in 20% of survivors and their outcome was significantly worse. This study demonstrates the importance of using CSF dynamics as an aid in diagnosis of posttraumatic hydrocephalus and identifying those patients who may benefit from shunt placement.

Reduced local cerebral blood flow in periventricular white matter in experimental neonatal hydrocephalus-restoration with CSF shunting.

The extent to which the reduction in CBF occurring in hydrocephalus is a primary or secondary event in the pathogenesis of the brain injury that ensues has not been clearly established. This is particularly true in neonatal hydrocephalus, where the disorder is most common, and where timing of the treatment of the developing nervous system is so important. We investigated the changes in local CBF (lCBF) in an animal model of severe progressive neonatal hydrocephalus before and after CSF shunting. Hydrocephalus was induced in 27 1-week-old kittens by percutaneous injection of 0.05 ml of 25% kaolin into the cisterna magna. Fourteen littermates acted as controls. The lCBF was measured by 14C-iodoantipyrine quantitative autoradiography after 1 week in 15 animals (8 hydrocephalic, 7 controls) and after 3 weeks in 26 animals (19 hydrocephalic, 7 controls) following induction of hydrocephalus. Twelve of the 3-week hydrocephalic group received a ventriculoperitoneal shunt 10 days following kaolin injection. At 1 week following induction of hydrocephalus, lCBF was globally reduced in cortical gray matter and white matter as well as deep subcortical structures. The maximum reduction was in the parietal white matter, to 37% of control levels. At 3 weeks a significant reduction in lCBF persisted only in the white matter (parietal, occipital, and corpus callosum; average, 42% of control levels), whereas cortical gray and deep subcortical structures had returned to normal levels spontaneously.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcranial Doppler ultrasonography in hydrocephalic children with tuberculous meningitis.

Studies have shown a close correlation between congenital hydrocephalus (CH) and the Gosling pulsatility index (PI) determined by transcranial Doppler ultrasonography (TCD). There have not previously been similar studies in children with hydrocephalus from tuberculous meningitis (TBM), and in particular where arteritis is a prominent feature. Fifteen children from each of these two groups were prospectively examined by TCD before and after CSF diversion. Fifteen children without hydrocephalus were similarly evaluated as controls. The fall in PI following surgery was compared. The mean fall in PI in the congenital hydrocephalic group was 0.723 (SD, 0.42) as compared with 0.089 (SD, 0.16) in the TBM group (p = 0.0001). Ten of the 15 children in the TBM group had infarcts revealed by CT. In these, the PI significantly postoperatively (p = 0.004), (0.014; SD, 0.12) when compared with values obtained (0.24; SD, 0.11) in five children without infarcts. These findings indicate that the clinically relevant fall in PI following CSF diversion in children with congenital hydrocephalus does not necessarily occur in children with hydrocephalus secondary to TBM, especially when complicated by cerebral infarcts.

Cognitive and motor abilities in preschool hydrocephalics

The neuropsychological performance of three groups of preschool children was evaluated: (a) one with hydrocephalus associated with myelomeningocele; (b) one with hydrocephalus associated with intraventricular hemorrhage and very low birth weight; and (c) a nonhydrocephalic normal comparison group. Multivariate profile analysis revealed lower levels of performance on measures of verbal and nonverbal cognitive skills for both groups of hydrocephalic children relative to normals. Comparison of group profiles on tasks requiring figure copying as opposed to figure matching and analysis of specific gross and fine motor skills revealed that both hydrocephalic groups had impaired visual-motor integration in the presence of average visual perceptual matching. In addition, different patterns of motor skill deficits were found for each hydrocephalic group. The results of this study suggest that decreased visual-motor integration and etiology-specific motor deficits are major sequelae of these forms of hydrocephalus in the preschool years.

The uptake of [ 14C]deoxyglucose into brain of young rats with inherited hydrocephalus

The effect of hydrocephalus on cerebral glucose utilization as reflected by deoxyglucose uptake has been examined in rats with inherited hydrocephalus at 10, 20, and 28 days after birth using a semiquantitative method. Injection of [ 14C]deoxyglucose intraperitoneally was followed by freezing the brain, sectioning, and quantitative autoradiography of 10 brain regions. Brain [ 14C] concentration, cortical thickness, and plasma glucose concentrations were measured. Maximal thinning of the cerebral cortex had already occurred by 10 days after birth, although obvious symptoms such as gait disturbance developed after 20 days. In control rats, the cerebral isotope concentration was lower and more homogeneous at 10 days than at 20 or 28 days, which may be a reflection of the use of metabolic substrates other than glucose in younger animals. In order to make comparisons between control and hydrocephalic groups, tissue isotope concentrations were normalized to cerebellar cortex which was not affected by the hydrocephalus at any age. In hydrocephalic rats at 10 and 20 days, the concentration of [ 14C] was lower in all areas except the inferior colliculi and pons but the reduction was only significant in the sensory-motor cortex at 10 days and in the caudate nuclei at 20 days. By 28 days after birth, all areas except the cerebellum (six cortical regions, inferior colliculi, pons, and caudate) had significantly lower isotope concentrations in the hydrocephalic group. It is concluded that cerebral glucose metabolism is significantly reduced by 28 days after birth in H-Tx rats with congenital hydrocephalus and that less marked reductions occur prior to 28 days.

The importance of "accessory" outflow pathways in hydrocephalus after experimental subarachnoid hemorrhage.

This study evaluated the changes in pathways of cerebrospinal fluid (CSF) outflow that accompanied acute and compensated hydrocephalus in the rabbit. Intraventricularly injected 99mTc antimony sulfide was used as a tracer of outflow pathways, and specified structures were counted 12 to 24 hours after injection. Fifteen rabbits were divided into three groups: 1) an acutely hydrocephalic group in which 3 cisternal injections of blood were followed by a study of CSF pressure, ventricular size, and CSF outflow pathways 1 week after the last injection; 2) a control group treated according to the same protocol, except that sterile saline was injected instead of blood; and 3) a chronic group also treated according to the same protocol but in which the animals were maintained an average of 4 weeks after the last blood injection. Ventricular size was measured by computed digitation and expressed as an area ratio of ventricle to brain (VBR). In control animals, 11.8% of the injected colloid dosage was found in cranial perineural lymphatic channels, and 4.8% appeared in the spinal cord. The mean CSF pressure was 149 +/- 20.2 mm H20 (mean +/- SE) and the mean VBR was 0.040 +/- 0.003. In animals evaluated 1 week after subarachnoid injection, accessory cranial perineural lymphatic outflow decreased significantly to 3.4%, and spinal cord activity increased to 9.8% (P less than 0.05, two-tailed t-test). These animals were hydrocephalic and had CSF pressure of 247 +/- 25.1 mm H20 (mean +/- SE) and VBR of 0.083 +/- 0.009.(ABSTRACT TRUNCATED AT 250 WORDS)

CEREBROSPINAL FLUID MYELIN BASIC PROTEIN IMMUNOREACTIVITY AS AN INDICATOR OF BRAIN DAMAGE IN CHILDREN

Cerebrospinal fluid (CSF) myelin basic protein (MBP) was measured blind by double antibody competitive inhibition radioimmunoassay (RIA) in 20 children who had seizures and 17 children with hydrocephalus. MBP values correlated with clinical outcome and mean maximum intracranial pressure (ICP) in the hydrocephalic group, and with type of convulsion in the epileptic group. A value of 20ng/ml or more was regarded as significantly raised. A significant rise in MBP levels could be demonstrated in those with ICP alone and in patients with additional problems, whose levels tended to be even higher. Hydrocephalic children with normal ICP and children with seizures had similar normal MBP levels, and in the latter group clinical outcome was not related to MBP levels. For individual patients CSF MBP is of little value as a prognostic indicator, or as a method of quantifying cerebral damage.

Experimental feline hydrocephalus. The role of biomechanical changes in ventricular enlargement in cats.

In a craniectomy-durectomy model of kaolin-induced feline hydrocephalus, the pressure-volume index (PVI) technique of bolus manipulations of cerebrospinal fluid (CSF) was used to study the biomechanical changes associated with hydrocephalus. Steady-state intracranial pressure (ICP), PVI, and the resistance to the absorption of CSF were determined acutely and 3 to 5 weeks later in hydrocephalic cats and time-matched control cats. Steady-state ICP was 11.0 +/- 2.1 mm Hg (+/- standard deviation) in the hydrocephalic cats, compared to 10.8 +/- 2.2 mm Hg in the chronic control group (p greater than 0.1). The ICP in both the chronic hydrocephalic and chronic control groups was significantly higher (p less than 0.001) than after acute durectomy (mean ICP 8.5 +/- 1.2 mm Hg). Immediately after dural opening, the mean PVI was 3.6 +/- 0.2 ml (+/- standard error of the mean); over time, it decreased to 1.3 +/- 0.1 ml in the chronic control group (p less than 0.001), but remained elevated in the hydrocephalic group at 3.5 +/- 0.4 ml (p less than 0.001). Resistance to CSF absorption was 9.1 +/- 1.4 mm Hg/ml/min immediately after dural opening and increased to 28.8 +/- 4.5 mm Hg/ml/min (p less than 0.001) in the hydrocephalic cats; it increased even further in the chronic measurements in control cats, to 82.3 +/- 9.2 mm Hg/ml/min (p less than 0.001). Ventricular size was moderate to severely enlarged in all hydrocephalic cats, and normal in the control group. These results indicate that the biomechanical profile of the altered brain container model of kaolin-induced feline hydrocephalus resembles that described in hydrocephalic infants. As shown in the control subjects, an absorptive defect alone is not sufficient to cause progressive ventricular enlargement. Increased volume-buffering capacity coupled with a moderate increase of CSF absorption resistance facilitates volume storage in the ventricles.

Auditory brain-stem responses in hydrocephalic patients

Auditory brain-stem response (ABR) was measured in 40 patients (80 ears) with confirmed hydrocephalus. Eighty-eight percent of these patients showed some form of ABR abnormality. Responses indicative of brain-stem dysfunction consisted of prolonged I–V interwave latency (38%), reduced V/I amplitude ratio (33%), and abnormalities in wave-shape of components III (27%) and V (53%). In addition, 70% of the patients had elevated ABR thresholds; 45% had responses in excess of 20 dB HL and the remaining 25% had no ABR activity. The etiology of the hydrocephalus, head circumference and brain-stem symptoms were not associated with particular ABR abnormalities. Communicating hydrocephalus correlated significantly with both prolonged I–V conduction time and absence of ABR activity, compared with non-communicating hydrocephalus. Four of the 9 patients retested showed ABR improvement on follow-up; one patient showed deterioration. The results were compared to our prior studies of ABR in 60 post-meningitic patients and in 100 severely neurologically impaired institutionalized children in whom the incidence of intrinsic brain-stem abnormalities was one-third and two-thirds that of the hydrocephalic group, respectively. The results of this study suggest that ABR can be used to document clinically unsuspected brain-stem pathology that may accompany hydrocephalus. Auditory brain-stem dysfunction is likely to complicate the assessment of hearing sensitivity in hydrocephalic patients.

Apraxic Tendencies in Children with Meningomyelocele

The purpose of this study was to investigate the presence of an apraxic condition in children with meningomyelocele. Subjects were grouped according to the presence or absence of hydrocephalus as diagnosed by a computerized tomography scan. Subjects performed tasks of simple movements and motor sequences first to verbal command and then to imitation. For simple movements there was a significant Group by Cue interaction. The hydrocephalic group, significantly inferior on the verbal cue, were noticeably better on imitation. For those subjects without hydrocephalus, such was unlikely due to a ceiling effect to the verbal cue. For motor sequences, there was a significant Cue and Group effect. Both groups improved to the visual cue with the nonhydrocephalus group being consistently superior. The results are discussed in terms of patterns of response, and a cognitive or brainstem/cerebellar-based disorder.

Rhenium-188 therapy of experimental hydrocephalus

Chronic hydrocephalus was produced in adult mongrel cats by the intracisternal injection of kaolin. After 10 days, Rhenium-188 in doses of 0.75 to 1.80 mCi was given by lateral ventricle to lateral ventricle perfusion to one group of hydrocephalic cats. Another group received doses of 4.6 to 5.1 mCi Rhenium-188 by a single intraventricular injection. Neither group showed diminution in the rates of formation or absorption of CSF or in the ventricular volume, nor was there evidence of alteration in thickness of the cortical mantle as shown by air ventriculograms. T/M ratios with Na 125 I were performed using choroid plexuses of normal, hydrocephalic, and Rhenium-188 treated hydrocephalic groups. The tissue-to-medium ratios were identical in both the normal and the hydrocephalic groups but were significantly lower in the Rhenium-188 treated cats.

Tactile matching in children with hydrocephalus.

16 hydrocephalic and 16 age matched normal children were required to match shapes felt by one hand with similar shapes presented to the same or the different hand. Overall ability on this task was much lower for the hydrocephalic subjects. This shows that the difficulty in processing spatial information which occurs in hydrocephalus in the visual modality is also present in the tactile modality. In addition, the hydrocephalic group had greater difficulty with “crossed” than “uncrossed” matches. This suggests a partial “split brain” effect in hydrocephalus as might be predicted from pathological reports of stretching of the corpus callosum in this condition.