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Biomedical subjects

R H Gooskens

Publications and source records attributed to R H Gooskens.

At least 37 records · Page 2Linked to original sources
PubMed1995

Monitoring intracranial dynamics by transcranial Doppler--a new Doppler index: trans systolic time.

Since the introduction of transcranial Doppler sonography (TCD) several investigators have described the relationship between raised intracranial pressure (ICP) and Doppler waveform. This waveform has been expressed by several indices, such as the pulsatility index (PI) and the resistance index (RI). These indices are used to demonstrate the presence of raised ICP. In childhood hydrocephalus this information can be used to indicate the need for shunt implantation. However, PI and RI do prove to have certain disadvantages as both are strongly influenced by the heart rate. Moreover, both indices have a broad range of reference values, especially in children. Therefore, they are not very reliable for detecting insidious changes in the ICP. These drawbacks are due to the fact that these indices are composed of blood flow velocity measurements and do not embody the slope of the TCD waveform itself. An ideal TCD waveform analysis should be performed concerning the time-related changes of the velocities. We present a hydrodynamic model, with its electrical analogue, which shows the effects of raised ICP on the intracranial hemodynamic system. Based on these physical findings we define a new Doppler index, the Trans Systolic Time, reflecting specific changes in the TCD waveform induced by changes in the mean ICP. The applicability of this index, compared with PI and RI, is illustrated by consecutive simultaneous TCD and AFP measurements in three children with hydrocephalus.

Blood Flow Velocity↗
PubMed1995

Intramedullary rodding in type III osteogenesis imperfecta. Effects on neuromotor development in 10 children.

We studied retrospectively gross motor development and the impact of intramedullary rodding in 10 children with type III osteogenesis imperfecta (OI). There was a pronounced delay in motor development and the order in achieving gross motor milestones differed from the normal developmental sequence. Static milestones developed at an earlier stage than dynamic milestones. Intramedullary rodding of the lower extremities prior to the age of 3.5 years enhanced neuromotor development, especially regarding the milestones supported standing, rolling from prone to supine and crawling with abdomen on the floor. The different sequence in achieving gross motor milestones should have implications for future rehabilitation programs and for orthopedic surgery.

Body Height↗
PubMed1991

Hereditary motor and sensory neuropathy of neuronal type with onset in early childhood.

Eighteen cases of a chronic progressive motor and sensory neuropathy of neuronal type with early onset are described. Based on the presented data and literature reports a condition is distinguished, which is in clinical, genetic and morphological aspects different from autosomal dominant HMSN type II. The condition corresponds to that described by Ouvrier et al. (1981). It shows a congenital or early childhood onset and causes a severe disability usually with wheelchair dependency already in puberty or later in adult life. The condition is probably transmitted by an autosomal recessive gene. Morphological features of biopsied nerves are an extensive loss of large diameter fibres with a shift to smaller diameters in the histogram. Regenerative features are almost absent in contrast to the distinct cluster formation in autosomal dominant HMSN type II. A maturation disturbance of peripheral motor and sensory neurons with a concomitant or secondary process of chronic neuronal degeneration is suggested. One dominantly inherited case in our group with an infantile onset exhibits clinical and morphological features consistent with an autosomal dominant HMSN type II.

Electrophysiology↗
PubMed1991

Visuomotor performance of normal and clumsy children. II: Arm-tracking with and without visual feedback.

Tracking performance was investigated in normal and clumsy children in two age-groups, six to seven and 10 to 11 years. Target signals moving unpredictably along a straight line had to be tracked, both with and without visual feedback. Performance was described in three ways: (1) performance in the low-frequency range (LF); (2) the delay between target signal and tracking movement (DL); and (3) a measure of tracking quality or over-all similarity in the shape of target signal and tracking movement (Q). Clumsy children in both age-groups had a lower tracking quality (Q) and longer delay (DL) than the normal children. Disturbances in the regulation of attention seemed to affect tracking performance, particularly of the six- to seven-year-old clumsy children. There was no significant difference between normal and clumsy children in the effect of visual feedback on tracking performance. This suggests that clumsiness is not linked to disturbance of integration of visual feedback information and motor processes.

Attention↗
PubMed1991

Visuomotor performance of normal and clumsy children. I: Fast goal-directed arm-movements with and without visual feedback.

The mechanisms underlying accuracy in fast goal-directed arm-movements were investigated in normal and clumsy children in two age-groups, six to seven and 10 to 11 years. Clumsy children in both age-groups had a longer movement time than normal children; this difference increased slightly when there was visual feedback. For both normal and clumsy children, the relative variability of the total distance moved was smaller than that of the distance moved during acceleration, indicating a variability reduction mechanism in the course of a movement. In the six- to seven-year-old group, the relative variability of the distance moved during acceleration and of the total distance was larger for clumsy than for normal children; this did not reach significance in the 10- to 11-year-old group. It is suggested that motor difficulties are linked to inaccuracy in open-loop control processes and to less efficient use of visual feedback.

Age Factors↗
PubMed1991

Myelination as an expression of the functional maturity of the brain.

A prospective cross-sectional study was performed on hydrocephalic infants and children. MRI was used to assess the state of myelination and to quantify the intracranial cerebrospinal fluid (CSF) volume repeatedly in all children. At the same time, neurodevelopmental testing was performed. A positive correlation was found between the progress of myelination and psychomotor development, but there were no significant correlations between CSF volume and myelination or between CSF volume and psychomotor development. This study provides strong evidence in favour of Flechsig's thesis that myelination expresses the functional maturity of the brain. The interdependency of neuronal maturation and progress of myelination are discussed.

Brain↗
PubMed1990

Mechanisms underlying accuracy in fast goal-directed arm movements in man.

This study investigated how accuracy is attained in fast goal-directed arm movements. Subjects were instructed to make arm extension movements over three different distances in random order, with and without visual feedback. Target width was varied proportionally with distance. Movement time was kept as short as possible, but there were well-defined limits with respect to accuracy. There appeared to be a large relative variability (variation coefficient [VC]) in the initial acceleration. The VC in the distance the hand moved during the acceleration phase was much smaller. This reduction was accompanied by a strong negative correlation between the initial acceleration and the duration of the acceleration phase. Further, the VC in the total distance moved was less than the VC in the distance moved during acceleration. This result indicates asymmetry between the acceleration and the deceleration phase. This is confirmed by the negative correlation between the distance the hand moved during acceleration and the distance it moved during deceleration. Withdrawal of visual feedback had a significant effect on movement accuracy. No differences were found in the parameters of the acceleration phase in the two feedback conditions, however. our results point to the existence of a powerful variability compensating mechanism within the acceleration phase. This mechanism seems to be independent of visual feedback; this suggests that efferent information (efference copies) and/or proprioceptive information is/are responsible for the timing of agonist and antagonist activation. The asymmetry between the acceleration and deceleration phase contributes to a reduction in the relative variability in the total distance moved. The fact that the withdrawal of visual feedback affected movement variability only during the deceleration phase indicates that visual information is used in the adjustment of antagonist activity.

Journal Article↗
PubMed1990

Arm-tracking performance with and without visual feedback in children and adults: developmental changes.

Tracking performance was investigated in children (aged 6-7 and 10-11) and in adult subjects. Target signals, moving unpredictably along a straight line, were tracked with the preferred arm, alternately with and without visual feedback. Qualitative observations indicate that tracking is based on continuous adjustments of the ongoing response to the continuously changing target position. No step-and-hold strategy could be detected in any of the three age groups. Tracking performance was described with four simple parameters, derived from linear systems analysis: (a) the delay between target signal and tracking movement (DL); (b) performance at the low-frequency range (LF), (c) performance at the high-frequency range (HF); and (d) a measure of tracking quality or overall similarity in the shape of target signal and tracking movement (Q). There was a considerable improvement in tracking performance with age, even after the age of 10-11, which was mainly demonstrated by a decrease in DL and increases in HF and Q. Tracking performance decreased only to a small extent when visual feedback was withdrawn. Age-related differences in the contribution of visual feedback to tracking performance could not be demonstrated.

Journal Article↗
PubMed1990

Cranial nerve palsy as a delayed complication of attempted infanticide by insertion of a stylet through the fontanel. Case report.

A child suffered a sixth and seventh cranial nerve palsy due to intracerebral insertion of a stylet. The stylet was introduced through the anterior fontanel, most probably in an attempt at infanticide. The migration of the stylet through the brain was monitored because the child was first examined 6 years earlier. At operation the cranial part of the stylet lay in the fourth ventricle, compressing the facial nerve as well as the nucleus of the abducens nerve. The lower part of the stylet had reached the C-5 level.

Abducens Nerve Injury↗
PubMed1989

Macrocephalies--a differentiated approach.

We present a clinical study of 43 macrocephalic children with a normal rate of headgrowth. The aims of the study were an evaluation of the usual criteria of macrocephaly and the drafting of a differentiated approach to the investigation of macrocephalics. Firstly, the value of head measurement in evaluating intracranial volume was assessed. As a golden standard for the intracranial volume the volume obtained by means of a CT-scan technique was used. It appeared that only about 30% of the variance of the intracranial volume was determined by the occipito-frontal circumference (OFC). A better estimation of the intracranial volume of the macrocephalic children was obtained by means of the "Utrecht Head Measure", the product of OFC-squared and the head height. Based on length measurements taken from CT-scans, the macrocephalic children were divided into three subgroups: megalencephaly (n = 15), extraventricular obstructive hydrocephalus (n = 5) and communicating hydrocephalus (n = 23). The clinical pictures of the megalencephalic and hydrocephalic children appeared to differ substantially. The megalencephalic subgroup had less neurological symptoms and physical abnormalities and showed a higher intelligence or a more advanced development or both. On the basis of our experience and theoretical considerations guidelines were developed for the assessment of patients with macrocephaly and a normal rate of head growth with a differentiated approach for megalencephalic and hydrocephalic patients.

Brain↗
PubMed1989

Magnetic resonance imaging of the cerebral aqueduct. Signal intensity time curves demonstrated by fast acquisition with multiple excitation (FAME).

Using cardiac-gated fast acquisition with multiple excitation (FAME), time curves of the cerebral aqueduct signals were derived in 19 healthy volunteers and 14 patients. A mean curve of the normal subjects was determined during systole. A relatively stable point of time was found at 270 msec after the R-wave supposed to be the reversal of the flow of cerebral-spinal fluid in the aqueduct. Different curves were noticed in complete aqueductal obstruction (n = 2); in other pathologic states, such as cerebral tumor (n = 3), normal pressure hydrocephalus (n = 3), and brain atrophy (n = 1), no different signal time curves were observed. Parameters such as aqueduct diameter, cerebro-spinal fluid volume and brain compliance are probably other important factors in aqueduct liquor flow.

Adolescent↗
PubMed1988

The value of estimating pressure-volume index in childhood macrocephaly. The relationship between pressure-volume index and the volumes of intracranial structures.

In this study on cerebrospinal fluid (CSF) dynamics in childhood macrocephaly, we investigated the relationship between the pressure volume index (PVI) and the volume of various brain structures. The most important variables of CSF dynamics are the outflow resistance (Ro) and the PVI. We applied a constant CSF infusion rate to measure the PVI. The volumes of intracranial structures were calculated by means of computed tomography. Our study revealed no significant correlation between PVI and CSF volume or between PVI and the intracranial volume, as suggested by earlier studies. We did, however, find a significant correlation between PVI and ventricle volume. These results indicate that in order to estimate PVI for clinical purposes, the ventricle volume rather than CSF volume or head circumference should be used.

Brain↗
PubMed1988

Megalencephaly: definition and classification.

The various definitions and classifications of megalencephaly are reviewed, and numerous diseases and syndromes associated with megalencephaly are listed. A new definition of megalencephaly based on quantitative radiographic features is proposed. We define megalencephaly as a brain volume which exceeds the mean by more than twice the standard deviation. Furthermore, a modified etiopathogenic classification of megalencephaly results in three main groups, viz anatomic, metabolic and dynamic megalencephaly. The clinical pictures in these main groups of megalencephaly, and the largest subgroup of anatomic megalencephaly, familial anatomic megalencephaly, appear to be quite different.

Brain↗
PubMed1988

Intracranial spaces in childhood macrocephaly: comparison of length measurements and volume calculations.

CT scanning was done to calculate the volume of intracranial spaces in children with the purpose of developing a reliable method of differentiating the various causes of macrocephaly. The technique has been applied to the CT scans of 60 apparently normal children, and the resulting graphs show the normal relationship between intracranial volumes and age from birth to 15 years. The measurements for 25 children with macrocephaly and normal rate of growth of head circumference were then compared with the reference values. It was possible to make accurate differentiations between megalencephaly, extraventricular hydrocephalus and communicating hydrocephalus. The advantage of this technique in relation to length measurements on CT scans is discussed. The authors advocate the estimation of the product of head circumference and head height as a much more reliable indication of normal and deviant head-size than head circumference alone.

Brain↗
PubMed1985

A cerebral cause of arthrogryposis: unilateral cerebral hypoplasia.

The authors describe a case of predominantly right-sided arthrogryposis in an infant with contralateral congenital cerebral hypoplasia and associated unilateral hydrocephalus. Diagnosis was made by prenatal ultrasonography and confirmed by postnatal cerebral CT-scanning. In addition to a variety of congenital neuromuscular disorders, arthrogryposis may be caused by disorders of the central nervous system. Hence, in the diagnostic approach of newborns with congenital contractures, cerebral malformations must be considered.

Abnormalities, Multiple↗