Jerzy Jurkiewicz

Analysis of postural sway in patients with normal pressure hydrocephalus: effects of shunt implantation

Poor postural balance is one of the major risk factors for falling in normal pressure hydrocephalus (NPH). Postural instability in the clinic is commonly assessed based upon force platform posturography. In this study we focused on the identification of changes in sway characteristics while standing quiet in patients with NPH before and after shunt implantation. Postural sway area and sway radius were analyzed in a group of 9 patients and 46 controls of both genders. Subjects spontaneous sway was recorded while standing quiet on a force platform for 30-60 s, with eyes open and then closed. Both analyzed sway descriptors identified between-group differences and also an effect of shunt implantation in the NPH group. Sway radius and sway area in patients exhibited very high values compared with those in the control group. Importantly, the effect of eyesight in patients was not observed before shunt implantation and reappeared after the surgical treatment. The study documents that static force platform posturography may be a reliable measure of postural control improvement due to shunt surgery.

Effect of dotarizine on CO2-dependent cerebrovascular reactivity

SummaryDotarizine is chemically related to calcium antagonist cinnarizine and flunarizine. The study presented investigates the influence of the drug on the diameter of cortical arteries and cerebral blood velocity measured in the MCA in two groups of anaesthetized cats. Changes of vessel diameter were measured indirectly using photographs of the cerebral cortex during experiments, and flow velocity was measured using transcranial Doppler sonography. Dotarizine was administrated by 20 minute intravenous infusion in a dose of 0.05 mg/kg/min. In the first group of animals the infusion was started during normoventilation, in the next group the infusion started during 30th minute of hyperventilation.The most conspicuous data were obtained in experiments conducted in hyperventilated animals where dotarizine abolished the vasoconstrictive effect of hyperventilation. The results suggest that dotarizine has a pronounced effect on basal as well as cortical arteries of the brain.

Posturography in Differential Diagnosis of Normal Pressure Hydrocephalus and Brain Atrophy

Differentiation between normal pressure hydrocephalus (NPH) and brain atrophy is difficult in clinical practice. The purpose of this paper was to apply two advanced statistical, pattern recognition methods: discriminant analysis (DA) and k-nearest neighbour (K-NN) for the classification of NPH and atrophy patients to approach computer aided differential diagnosis. The classification is based on a few measures of the center of foot pressure (COP) movements (radius, area, and length). The posturography method gives a measure of current postural stability by a quantitative evaluation of postural sways. Measurements have been performed in the standing upright position in two conditions: with eyes open (EO) and closed (EC). The study comprises 18 patients (mean age 64 ±13 years) diagnosed as normal pressure hydrocephalus and qualifying for shunt implantation. The patients were evaluated by static posturography twice: before and after surgery. The NPH patients were compared with 36 atrophy patients (mean age 64±13 years) and 47 healthy persons (mean age 60 ±7 years). There were two basic dissimilarities in the NPH patients before surgery in comparison with the other groups: very large sways and their independence from vision. Over 90% of the NPH cases both before and after surgery were correctly classified. There also were over 90% of correctly classified patients if we compared the before surgery NPH and atrophy patients. Further posturographic measurements and data collection are needed to verify these results.

Regional differences of cerebrovascular reactivity effected by calcium channel blocker - dotarizine.

Dotarizine, a novel antimigraine prophylactic drug, is chemically related to Diphenylbutylpiperazines, which are known to have Ca(2+)-antagonistic, alpha-adrenolytic and antihistaminic properties. Additionally, Dotarizine exhibits strong 5-HT2 receptor-specific antiserotoninergic properties. The vasostabilizing effect of Dotarizine on cerebrovascular reactivity during different ventilation conditions was demonstrated in various in vitro and in vivo studies. In the presented study, the effect of chronic oral administration of the drug on vascular reactions of different areas of cerebral vessels following hyperventilation was investigated. The experiments were carried out on two groups of experimental animals (rabbits). In the first group (6) 25 mg/kg of Dotarizine dissolved in 0.25% agar was administered orally for 5 days twice daily. The control group of animals (6) was fed with agar of the same concentration according to the same time schedule. During the experiment, 15 min hyperventilation was performed and blood flow velocity (BFV) in the middle cerebral artery (MCA) and the basilar artery (BA) was recorded using Transcranial Doppler apparatus (TCD) before and after hyperventilation state. The obtained results revealed a strong antivasoconstrictive effect of Dotarizine on cerebral vessels reactivity during hyperventilation. In the control experimental group, the 15 min hyperventilation caused a decrease in the mean BFV in MCA and BA by 36 and 14%, respectively, and in the drug-treated group under the same ventilation conditions the decrease of the mean BFV in BA was only 6% and even a slight increase (8% as compared with control values) of BFV in MCA was observed. Comparison of the pulsatility index (PI) values demonstrated a significant decrease of vascular resistance in MCA in the Dotarizine-treated group of animals (P<0.1). From the obtained results it can be concluded that chronic oral administration of a novel compound (Dotarizine) diminishes the vasoconstrictive effect of hyperventilation on cerebral vessels in rabbits. The influence of this drug demonstrates regional differences in the cerebrovascular reactivity and it appears to change the vascular resistance in the small arteries of the cerebrovascular system. Thus, it can be recommended as a good prophylactic antimigraine compound due its vasostabilizing properties.

Intracranial volume reserve determination using CT images, numerical analysis and lumbar infusion tests. An experimental study

SummaryThe epidural balloon compression model in the cat was used in intracranial volume reserve studies. The evaluation of the intracranial volume-pressure relations was based on the lumbar infusion test data: intracranial pressure, CSF outflow resistance, volume-pressure response and on CT images numerical analysis (CTINA) values. Two methods were applied and compared in the study: lumbar infusion test and CT images numerical analysis. The determinations were performed at the balloon volumes of 0.5 ml, 1.0 ml, and 1.5 ml. First statistically significant changes were found at the balloon volume of 0.5 ml i.e. the increase of CSF outflow resistance and volume-pressure response (data obtained in lumbar infusion test) and the decrease in CTINA values. The rise of intracranial pressure was less informative as it was observed at the balloon volume of 1.5 ml. Therefore CTINA seems to be a very useful noninvasive screening method in clinical studies of intracranial volume reserve.

Cerebrovascular reactivity evaluated by transcranial doppler sonography in patients after aneurysmal subarachnoid haemorrhage treated with microsurgical clipping or endovascular coiling technique

Abstract Objective: To examine cerebrovascular reactivity in patients after subarachnoid haemorrhage (SAH) during long-term follow-up, using Acetazolamide test and transcranial Doppler (TCD) monitoring of blood flow velocities (BFVs), to compare of CO2 reactivity between patients after SAH treated with three different methods: surgical (clipping), endovasculary (coiling) and conservative. Methods: The study was performed in a group of 24 patients treated for SAH. Cerebrovascular reactivity (CVR) has been evaluated after intravenous administration of 1000 mg of Acetazolamide. Studied patients were divided into three groups: group I (n = 10) treated with clipping, group II (n = 8) treated with coiling and group III (n = 6) - patients with negative angiography treated conservatively. Results: Results of this study have shown that: (1) BFVs were normal in cerebral arteries and did not differ between right and left head sides, (2) CVR was normal in all studied patients, (3) method of aneurysm treatment as well as its localization had no influence on BFV and CVR, and (4) occurrence of vasospasm in early days after SAH did not result in permanent disturbances of CO2 arterial reactivity. Conclusion: BFV values in cerebral arteries were in normal range and did not differ on the left and right head sides. CVR was normal in all examinated patients. A method of the ruptured aneurysm treatment and its localization had no influence on CBFV and CRV. Vasospasm in early period after SAH did not provoke a persistent impairment of CO2 reactivity.

Effects of the calcium channel blockers Dotarizine and Flunarizine on cerebrovascular reactivity

Dotarizine and Flunarizine are piperazine derivatives considered to be effective compounds for the treatment of various cerebrovascular disorders. In the present study the influence of these two drugs on changes in cerebral vessel diameter and blood flow velocity were measured and compared utilising transcranial Doppler sonography during hyperventilation in anaesthetized cats. Drugs were administered in 15 min intravenous infusions at a dose of 0.05 mg/kg/min. This investigation revealed that the 15 min intravenous administration of both compounds abolished the cerebral vasoconstrictor effects of hyperventilation and due to vasodilator effects they increased blood flow velocity to initial values. No statistically significant differences were found between the vasodilator effects of Dotarizine and Flunarizine. Results obtained suggest that Dotarizine, a novel piperazine derivative, has similar vasodilator and Ca2+ channel blocking effects on cerebrovascular reactivity compared to the widely clinically applied Flunarizine.

Effect of haemodilution on experimental cerebral oedema in cats

The effect of haemodilution with Dextran 60 on experimental cerebral oedema produced by the modified method of Ishii, Hayner, Kelly & Evans (1959) is described. The intracranial pressure was measured from the cisterna magna or epidurally in the parieto-occipital region. In the group of cats subjected to haemodilution, with a haematocrit of 27.20 +/- 1.48%, the intracranial pressure first increased by 500% and, after 1.5 h, began to fall gradually so that at the end of the experiment it was only 160% of initial value. In the other experimental group in which haemodilution with a haematocrit of 27.40 +/- 1.14% was started after 6 h of the experiment, the intracranial pressure gradually fell for the next 6 h from 350% of initial value of 200% of initial value after 12 h. It was concluded that haemodilution slows down the development of cerebral oedema, and can be employed in the treatment of fully developed oedema.

The Effect of Hypocapnia on Normal and Increased Intracranial Pressure in Cats and Rabbits

Hyperventilation (HV) is very frequently employed to lower increased intracranial pressure (ICP) (1,2). The beneficial effect of HV is the result of vasoconstriction. This, however, may lead to hypoxia.

Effect of haemodilution on the cerebral blood flow and blood--brain barrier in experimental cerebral oedema in cats.

Abstract The effect was studied of normovolaemic haemodilution with Dextran 60 to a haematocrit of 25.9 ± 3.5% on the cerebral blood flow and on the blood-brain barrier during experimental oedema produced in cats by the modified method of Ishi, Hayner, Kelly & Evans (1959). The cerebral blood flow was measured by the intracarotid 133 Xe method. The extent of disturbances of the blood-brain barrier was evaluated on the basis of extravasation of intravenously administered Evans blue. In the control group, comprising cats which had not been subjected to haemodilution, the cerebral blood flow dropped gradually during epidural compression and was 49% of the control value after 6 h of compression. At the same time, disturbances of the blood-brain barrier were observed in the cortex of the compressed hemisphere and in the subcortical nuclei of both hemispheres. Haemodilution increased the cerebral blood flow by 34% of control value. The decrease in cerebral blood flow during epidural compression produced after haemodilution began later and appeared to be smaller than in the control group. After 6 h of compression the cerebral blood flow fell by only 26% of the control value. In this group of animals the blood-brain barrier in the cerebral cortex of the compressed hemisphere was affected in the immediate neighbourhood of the compression site. It was concluded that haemodilution has a beneficial effect in diminishing the effects of oedema on the brain.