Neuropsychological and neurophysiological evaluation of cognitive deficits related to the severity of traumatic brain injury.

OBJECTIVES: Cognitive impairment is a common permanent sequela of traumatic brain injury (TBI). Its objectivization is based on neuropsychological and neurophysiological assessment. Neuropsychological evaluation requires a test battery, whereas for neurophysiological assessment the most significant is application of P300 Event-Related Potentials (ERPs). The aim of the study was to determine whether it is possible to differentiate between degrees of severity of TBI on the basis of neuropsychological and neurophysiological parameters. PATIENTS AND METHODS: A total of 90 patients with closed TBI were evaluated at least one year after trauma. Subjects were classified into three groups according to severity of TBI: mild, moderate and severe. In all subjects the Intelligence Test, the Wisconsin Card Sorting Test (WCST) and P300 ERPs were performed. RESULTS: General intelligence measures did not prove sensitivity enough to differentiate levels of severity of TBI, whereas the number of achieved categories on the WCST significantly discerned patients with mild and moderate TBI from patients with severe TBI. Perseverative errors significantly separated patients with mild TBI from patients with moderate and severe TBI. Non-perseverative errors significantly differentiated only patients with mild TBI from patients with severe TBI. Finally, P300 latency (EPLAT) significantly differentiated patients with mild TBI from patients with moderate and severe TBI. The results show that the applied test battery can discriminate between different levels of severity of TBI and emphasize the importance of P300 ERP in the evaluation of patients with brain injury. CONCLUSIONS: Our findings indicate that the WCST and ERP P300 latency have a significant role in the assessment of cognitive deficit related to TBI.

Forensic aspect of late subjective complaints after traumatic brain injury.

BACKGROUND: The subjective complaints in patients with TBI (Traumatic Brain Injury) may persist for years. The most frequent complaints are headache, dizziness, drowsiness, mood disturbances, and memory and concentration disturbances. It is assumed that these complaints are caused by injury itself on one hand and psychological, emotional and motivation factors on the other. AIM: Evaluation of late posttraumatic complaints in patients with TBI more than a year after the trauma, and establishing their correlations to the severity of TBI and involvement in the lawsuits for financial compensation (litigation). MATERIALS AND METHODS: Ninety patients with the diagnosis of TBI were divided, according to the severity of the injury, in two groups: mild and with moderate-to-severe. The second classification criterion was litigation. A subjective complaints scale has been designed for the purpose of this research taking into consideration both anamnesis and hetero-anamnesis data. RESULTS: Cognitive disturbance, aggressiveness and sleep disturbance are more frequently reported by the subgroup of moderate-to-severe TBI patients, and they have not been related to the litigation. Posttraumatic headache (PTH) turned out to be a distinctive complaint regarding both classification criteria. Vegetative disturbances are significantly related to litigation, but not to the degree of injury. CONCLUSIONS: Predictive complaints reflecting the severity of TBI are memory deficit, concentration problems, and aggressiveness and sleep disturbance. Vegetative disturbances are predictive in relation to compensation claims. PTH is important from the forensic point of view for the patients with moderate to severe TBI.

Healthcare technology and technology assessment.

New technology is one of the primary drivers for increased healthcare costs in the United States. Both physician and industry play important roles in the development, adoption, utilization and choice of new technologies. The Federal Drug Administration regulates new drugs and new medical devices, but healthcare technology assessment remains limited. Healthcare technology assessment originated in federal agencies; today it is decentralized with increasing private sector efforts. Innovation is left to free market forces, including direct to consumer marketing and consumer choice. But to be fair to the consumer, he/she must have free knowledge of all the risks and benefits of a new technology in order to make an informed choice. Physicians, institutions and industry need to work together by providing proven, safe, clinically effective and cost effective new technologies, which require valid pre-market clinical trials and post-market continued surveillance with national and international registries allowing full transparency of new products to the consumer--the patient.

Mechanical testing of bioresorbable implants for use in metacarpal fracture fixation.

The purpose of this study was to evaluate the mechanical properties of a bioresorbable plate and screw system that was developed for the treatment of unstable metacarpal fractures and to compare the strength and stiffness of this system with those of conventional titanium plates and screws. Using a 4-point bending test, we measured the strength and stiffness of these implants over a 12-week period of in vitro degradation. Our data suggest that these implants provide stable bending strength and stiffness for 8 weeks and gradually lose their strength over a period of 12 weeks. Further research is necessary to determine whether this level of fixation is adequate to stabilize unstable metacarpal fractures.

[Manifestations of visceral and ocular symptoms of toxocariasis in a 6-year-old boy]. / Pojava visceralne i okularne klinicke slike toksokarijaze kod sestogodisnjeg decaka.

In the past 10 years we have examined 137 cases of toxocariasis, predominantly in children. Three cases were with unilateral ocular involvement. The article reviews a 6-year-old boy with left side strabismus and granulomatous chorioretinitis. Laboratory examinations revealed blood eosinophylia 24% and IgG against Toxocara canis larvae in titer 1:320 by indirect immunofluorescent assay. In epidemiologic anamnesis we concluded that about 4, 5-year-long geophagia was the source of infection.

In vivo evaluation of coralline hydroxyapatite and direct current electrical stimulation in lumbar spinal fusion.

STUDY DESIGN: An animal model of posterolateral intertransverse process lumbar spinal fusion using autologous bone, coralline hydroxyapatite, and/or direct current electrical stimulation. OBJECTIVES: To evaluate the effect of an osteoconductive bone graft substitute and direct-current electrical stimulation on the rate of pseudarthrosis in a rabbit spinal fusion model. SUMMARY OF BACKGROUND DATA: Conventional techniques for the surgical treatment of degenerative conditions in the lumbar spine have a substantial failure rate and associated morbidity. Bone graft substitutes and electrical stimulation are alternative techniques to enhance fusion rates and limit the morbidity associated with posterolateral intertransverse process fusion using autologous iliac crest bone graft. METHODS: Fifty-three adult female New Zealand White rabbits underwent single-level lumbar posterolateral intertransverse process fusion. Animals were assigned to one of four groups using either autologous bone (Group I), coralline hydroxyapatite with autologous bone marrow aspirate (Group II), coralline hydroxyapatite with a 40-microA implantable direct current electrical stimulator and bone marrow aspirate (Group III), or coralline hydroxyapatite with a 100-microA implantable direct current electrical stimulator and bone marrow aspirate (Group IV). Animals were killed at 8 weeks, and fused motion segments were subjected to manual palpation, mechanical testing, and radiographic and histologic analysis to assess the fusion mass. RESULTS: Successful fusion was achieved in 57% (8/14) of animals in Group I, 25% (3/12) in Group II, 50% (6/12) in Group III, and 87% (13/15) in Group IV. Mean stiffness and ultimate load to failure were significantly higher in Group IV than in all other groups (P < 0.05). Histologic analysis demonstrated a qualitative increase in fusion mass in Group IV versus all other groups. CONCLUSIONS: Direct-current electrical stimulation increased fusion rates in a dose-dependent manner in a rabbit spinal fusion model. Coralline hydroxyapatite is an osteoconductive bone graft substitute, and thus requires an osteoinductive stimulus to ensure reliable fusion rates. Furthermore, coralline hydroxyapatite and direct current electrical stimulation can be used together to increase fusion rates in a rabbit spinal fusion model while avoiding the morbidity associated with harvesting iliac crest bone.

Survivorship analysis of hips treated with core decompression for nontraumatic osteonecrosis of the femoral head.

We reviewed the long-term results of core decompression for the treatment of nontraumatic osteonecrosis of the femoral head, performed in thirty-four patients (fifty-four hips) between January 1, 1981, and June 30, 1995. Twenty patients (59 percent) had bilateral involvement. The mean age of the patients at the time of presentation was thirty-eight years (range, twenty-two to eighty-three years). The presumed risk factors were use of corticosteroids (thirty-seven hips), excessive intake of alcohol (eight hips), and use of adrenocorticotropic hormone for the treatment of multiple sclerosis (two hips); the remaining seven hips had idiopathic osteonecrosis. According to a modification of the classification system of Ficat and Arlet in combination with the system of Steinberg et al., thirteen hips were stage I (normal radiographs) preoperatively; seven, stage IIA sclerotic; sixteen, stage IIA cystic or sclerocystic; ten, stage IIB (transitional stage, with a crescent sign); and eight, stage III (collapse). The mean duration of follow-up after the core decompression was 120 months (range, twenty-four to 196 months). The result was considered successful if the patient was asymptomatic, with no progression of the disease, and unsuccessful if there was radiographic failure (progression to stage III [collapse]) or clinical failure (the need for a subsequent operation), or both. The Kaplan-Meier product-limit method was used to estimate clinical and radiographic survival. Overall, twenty-six hips (48 percent) had a satisfactory clinical result and twenty (37 percent) survived according to radiographic criteria. Radiographic or clinical failure, or both, were seen in four of the thirteen stage-I hips, none of the seven stage-IIA sclerotic hips, thirteen of the sixteen stage-IIA cystic or sclerocystic hips, nine of the ten stage-IIB hips, and all eight stage-III hips. On the basis of the Cox proportional-hazards regression model, significant predictors of overall failure included an advanced preoperative radiographic stage (p < 0.0001), a shorter duration of symptoms (p < 0.05), and use of corticosteroids (p < 0.05). No association was found between age, gender, excessive intake of alcohol, or renal transplantation and the overall outcome. Two patients (two hips; 4 percent) had a postoperative complication. One patient had a fracture of the femoral neck, and the other had a hematoma. Our findings suggest that core decompression is a safe and effective procedure for the treatment of stage-I or stage-IIA sclerotic disease. These data also demonstrate the importance of differentiating between stage-IIA sclerotic disease and stage-IIA cystic or sclerocystic disease. We believe that core decompression has a limited role in the operative management of patients who have evidence of cystic changes in the femoral head on plain radiographs.

Radiographic appearance of the normal distal tibiofibular syndesmosis in children.

In adults, a tibiofibular clear space (i.e., distance from the incisura fibularis to the medial fibula) of > or = 6 mm or a loss of tibiofibular overlap has been reported to correlate with injury to the distal tibiofibular syndesmosis. We reviewed anteroposterior (AP), lateral, and mortise ankle radiographs from 106 children (50 boys, 56 girls) aged 1-15 years in an attempt to assess whether these criteria are applicable to children. The incisura was detectable at a mean age of 8.2 years for girls and 11.2 years for boys. The range of tibiofibular clear space among the 48 children with a detectable incisura was 2-8 mm; seven (23%) of these 48 children had a clear space of > or = 6 mm in one or more views. The mean age at which the tibiofibular overlap began to appear on the AP view was 5 years for both genders, whereas on the mortise view, it was 10 years for girls and 16 years for boys. The criteria used to evaluate the integrity of the distal tibiofibular syndesmosis in adults do not apply to children in this normal study population.

[Specific antiepileptic therapy in childhood]. / Specificnosti antiepilepticne terapije u razvojnom dobu.

INTRODUCTION: This paper deals with basic rational antiepileptic therapeutic procedures in children with special consideration of numerous specificities which occur in childhood: difficulties in establishing correct syndrome diagnosis, predominantly after the first or first few seizures which makes it difficult to decide about appropriate syndrome-specific therapy in regard to efficacy, mechanism of action and range of antiepileptic action; difficulties in assessment of subjective factors (their adverse effects and recognition of seizures with subjective symptoms), children's vulnerability in regard to drug toxicity; age-specific pharmacokinetics of these drugs. MATERIAL AND METHODS: The number of available antiepileptics today is great due to new drugs, but carbamazepine (CBZ) and valproate (VAL) are still basic antiepileptics, although carbamazepine's action is reduced to partial epilepsies. The paper describes range of action of available antiepileptics in regard to classification of epileptic seizures and most frequent epileptic syndromes. DISCUSSION: Adverse effects of antiepileptic agents depend on the age, so examples of age-dependent adverse effects are given considering conventional and new antiepileptics. It is well known that optimal control of seizures depends not only on correct choice of drug, but also on appropriate dosage; it is necessary to be informed about age-dependent characteristics of clinical pharmacokinetics: resorption, metabolism, elimination and half-life of antiepileptics. Although 70-80% of children may be well treated with monotherapy, 15% of children require combination of 2 or more drugs causing drug interactions in resorption, distribution, metabolism and elimination. Examples of antiepileptic interactions as well as interactions of other drugs and antiepileptics are given. The paper also deals with special importance of the psychosocial aspects of epilepsy. These children are often unaccepted by others, mostly because others are afraid of their disease, which contributes to poor quality of life of these children. Development of intellectual, emotional functions, physical development and socialization, apart from affecting the choice of drug, make epilepsy treatment in children more complex, with special emphasis on mental-hygienic aspects of complete management of children. CONCLUSION: Only a complex approach to child suffering from epilepsy may provide optimal development, quality of life improvement and complete social integration. Rational therapy of epilepsy in children requires good knowledge not only of age-specific syndromes, clinical pharmacology of anticonvulsants, their efficacy and range of action, but also specificity of their metabolism in children, profile of adverse effects as well as facing numerous nonmedical problems.

[Occurrence, causes and clinical characteristics of status epilepsy in adults]. / Ucestalost, uzroci i klinicke karakteristike epilepticnog statusa kod odraslih.

INTRODUCTION: Status epilepticus, particularly grand mal, is one of the gravest and most dramatic conditions in neurology requiring immediate attention. Status epilepticus can occur in epileptic patients, often with higher mortality rates in symptomatic than idiopathic, but also as an initial symptom of a number of neurological and systemic diseases. No data are available on the exact incidence rates of status epilepticus. According to some assessments, 10% of patients have at least one status epilepticus in their lifetime (3,6). The prognosis mostly depends on the main cause, time in which seizures are stopped and age of patients. Latest data available in literature suggest the mortality rate of 2-8%. MATERIALS AND METHODS: We analyzed frequency of hospital admissions, causes and clinical characteristics of status epilepticus in adults. The study was retrospective, based on case histories of epileptic patients from the Intensive Care Unit of the Neurology Clinic in Novi Sad in 1990, 1993 and 1995. Special emphasis was placed on differences in studied parameters between cases confirmed earlier and those with status epilepticus occurring as an initial symptom of some other illness or condition. RESULTS: Number of hospital admissions rose slightly in the interval observed in comparison with total admissions (0.68% in 1990, 1.24% in 1993, and 1.73% in 1995) (Tabs 1 and 2). During 1993, status epilepticus was more frequent in cases confirmed earlier (69%) compared with the years 1990 (56%) and 1995 (43%) (Graf.1). Epileptic patients were younger on the average than nonepileptic ones (Tab. 3). Status epilepticus occurred more often in male patients (Tab. 4). Irregular treatment was the prevailing cause in epileptic patients (Tab 5). Symptomatic status epilepticus was reported higher in 1990 and 1995, and stroke was definitely the predominant cause (Tab 6). Convulsive grand mal status prevailed in all patients (Graf 2). Focal status was a more frequent finding in nonepileptic patients (Graf 3). Every third in 16 patients died in 1993 and every fifth in 23 in 1995 probably due to the acute destructive brain damage rather than the status itself. No deaths occurred in 1990. DISCUSSION: According to research carried out by other authors, half of grand mal status cases occurred in confirmed epileptics (4). In our study the grand mal status was reported in 70.4% cases of epilepsy. Primary cause was abrupt withdrawal of antiepileptic treatment, infections, alcohol abuse and use of convulsive drugs. This is compatible with our results which confirm that grand mal status either primary or with secondary generalization prevail in both groups of patients (7,8,9). In terms of causes of status epilepticus in nonepileptic patients, literature data mainly suggest cerebral trauma, frontal brain tumors, cerebral arteriosclerosis or other vascular disorders and anaphylaxis (4). Our results point to stroke as the major cause of status epilepticus in nonepileptic patients, similar with data presented by Towne (10). There is no data in literature concerning the relation between sex of patients and occurrence of status. In our study status epilepticus occurred more frequently in male patients. CONCLUSION: The grand mal status was the major clinical type of status in all patients and was primarily caused by discontinued or irregular antiepileptic treatment in patients with confirmed epilepsy, and by stroke in nonepileptic patients.

[Subjective syndrome after head injury]. / Subjektivni sindrom nakon povreda glave.

UNLABELLED: DEFINITION AND CLASSIFICATION PROBLEMS: Post-traumatic or post-commotion syndrome is one of the most controversial entities in studying consequences of craniocerebral trauma. Part of this problem arises from impossibility of adequate translation of the term brain concussion. Post-concussion syndrome is a broader concept than post-commotion and includes, if not a whole, than part of the post-contusion syndrome. There are also some other terms in the literature: post-traumatic syndrome, post head injury syndrome, post head injury syndrome or symptoms and the old term post-traumatic encephalopathy. Terminological imprecisions have not been solved yet, but the notion itself is determined by relative standard symptoms often associated with closed craniocerebral trauma, but without precise connection with the severity of the trauma. In the classification of mental disorders and behavior disorders, this syndrome is coded as FO7.2. ETIOLOGY: In regard to the etiology of this syndrome some authors speak in favor of psychogenic and some of organic etiology, while Levin considers symptoms of post-commotion syndrome to start as organic and persist as psychic. Wechsler classified subjective disorders after head injuries into 4 categories: simulation, traumatic hysteria, traumatic encephalopathy and traumatic neurosis. The author does not deal with the origin of symptoms, whereas the classification itself suggests priority of psychic to organic factors (11). Those who speak in favor of organic etiology, think that axon damage and neuron damage are organic substrate in mild brain injuries, while fibrous degenerations of the cerebral hemisphere and brain stem are the organic base in severe traumas. On the other hand, many scientists primarily point to psychic moments, especially to importance of aggravation and simulation as well as compensation or rental neurosis in persistent post-traumatic syndrome. Most scientists agree that personality characteristics influence the development of post-traumatic syndrome and can predispose aggravation and simulation, whereas these symptoms more often occur in neurotic persons. The latest investigations reveal that classification in regard to etiologic factors--organic and psychogenic--is an anachronism. Long and Novac state that 80% of persons with cerebral trauma spontaneously speak about symptoms of the post-traumatic syndrome, while by targeted evaluation the percentage rises to 90%, so that they think that universality of symptoms points to their common origin. CONCLUSION: If the post-traumatic syndrome is though of as a line with organic dementia at one end and traumatic neuroses at the other, then this syndrome can be placed at different positions. Some authors put it close to the neurotic syndrome or regard it to be the neurotic syndrome itself, while others, mostly due to homogenity of the clinical picture, believe that this syndrome has an organic cause.

[Evaluation of cognitive deficits after craniocerebral injury]. / Mogucnosti procene kognitivnog deficita nakon kraniocerebralne traume.

The study included 90 persons, one year after experiencing closed craniocerebral trauma. The purpose was to determine, by neuropsychological and neurophysiological methods, the presence of cognitive deficit as a result of cerebral trauma. It is possible to objectivize the organically conditioned cognitive deficit in case of a significant number of patients, and also, by the application of certain methodology, to grade the intensity of existing changes. When compared with other examined parameters, the presence of cognitive deficit was more often in patients of older ages and in those with more serious craniocerebral trauma. A special attention was made to the sensitivity of the used instruments for the verification of cognitive deficit. Among them, Wisconsin test and the method of cognitive evoked potential P-300 appeared to be the most reliable ones.

[Mechanisms of epileptogenesis and antiepileptic drugs]. / Mehanizmi epileptogeneze i antiepilepticki lekovi.

Contemporary data about the mechanisms of epileptogenesis are reviewed. The role of the neuronal membrane and synapsis in the neurons changed by epilepsy is particularly pointed out. The concept of "the paroxysmal depolarizational shift" is defined. Role of some neurotransmitters in the mechanisms of epileptogenesis and their classifications into excitatory and inhibitory ones are also presented. It is pointed to a great variety of receptors for neurotransmitters as well as the role of calcium ions in mechanisms of epileptogenesis. A review of "classical" and new antiepileptic drugs is created and possible mechanisms of their effect are stated. The same antiepileptic medicaments are listed in a special table depending on the type of epilepsy in which they have effect. It is certain that during the last two decades electrophysiologic, biochemic and pharmacologic researchers have significantly improved the knowledge of the main occurrences responsible for epileptogenesis. However, a lot of facts are still doubtful.

[Correlation of comprehensive diagnosis and functional results after cerebrovascular stroke]. / Korelacija kompleksne dijagnostike i funkcionalnog ishoda nakon cerebrovaskularnog insulta.

Cerebrovascular insult is a focal neurological disorder with sudden onset and fast development caused by pathological changes of the blood vessel and accompanied by functional disorder which requires rehabilitation. The program of rehabilitation differs from patient to patient depending on physical, emotional and social-economic factors. The aim of this paper was to underline the degree of sensibility of electroencephalography and somatosensory evoked potentials, which can serve, with other corresponding methods and clinical parameters, as criteria in prognosis of the further course of the disease, in planning rehabilitation and therapeutic treatment and functional result prognosis in hemiplegic patients.

Instrumentation of the cervicothoracic junction after destabilization.

STUDY DESIGN: The biomechanics of three different instrumentation constructs applied at the destabilized cervicothoracic junction were evaluated. OBJECTIVES: To find an efficient way in restoring stability of the cervicothoracic junction in cases with and without laminectomy. SUMMARY OF BACKGROUND DATA: Different instrumentation techniques have been evaluated biomechanically and used clinically for managing instabilities between the fourth and sixth cervical vertebrae. These constructs have not been evaluated at the cervicothoracic junction. METHODS: Six human spines were tested nondestructively in axial torsion, flexion, and extension with the C6-T2 motion segments left unconstrained. The three-dimensional displacements and rotations between C7 and T1 vertebrae were measured using a sonic digitizer. After intact testing, a distractive-flexion Stage 3 cervical spinal injury was simulated surgically between C7 and T1. The specimens underwent sequential instrumentation and mechanical testing with three constructs: posterior Synthes lateral mass plate, posterior pediatric Cotrel-Dubousset rod system with lamina hooks and a crosslink, and anterior Synthes cervical locking plate. RESULTS: Posterior stabilization techniques had statistically more stiffness than anterior plates. The Cotrel-Dubousset system offered the largest stiffness ratio (instrumented/intact) in flexion, extension, and rotation. There was no statistical difference between posterior plates and Cotrel-Dubousset instrumentation. The stiffness of the anterior plate did not differ significantly from the intact spine. CONCLUSION: Our data show that instability of the cervicothoracic junction can be efficiently restored by either anterior plates, posterior plates, or posterior hook-rod constructs (Cotrel-Dubousset). Posterior constructs showed increased stiffness over anterior plates.

[Occlusive hydrocephalus as a complication of von Recklinghausen's neurofibromatosis--case report]. / Okluzivni hidrocefalus kao komplikacija neurofibromatoze von Recklinghausen--prikaz slucaja.

Phacomatoses are hereditary disease caused by germinative matrix disorder. Apart from known proliferative and tumor processes on peripheral nerves and their roots which make up a familiar picture of this disease to all neurologist, other tissue and organ malformations of octo and mesodermal origin may occur. This is a case report of a girl with neurofibromatosis type I after Riccardi with occlusive hydrocephalus complication. We pointed to a great number of neurofibromatosis complications, their prompt detection and treatment.

[Cognitive deficits in alcoholics--significance of cognitive evoked potentials (P-300)]. / Kognitivni deficit kod alkoholicara--znacaj metode kognitivnog evociranog potencijala (P-300).

Method of event related potential has proved to be very useful in estimation of higher nerve functions damage, especially P-300 component as a precise indicator of cognitive and perceptual functioning. According to data available in literature, significant degree of correlation exists between evoked potential parameters (amplitude and latency) and deficit of psychic functions. The sample consisted of 37 patients (male and female) who had signs or alcohol-induced organic mental disorder (according to ICD-10). "Oddball" paradigm of P-300 was used. The results were compared with control group of 20 healthy persons. The results emphasized lower amplitude and prolonged latencies in the group of alcoholics. These findings were more significant in female subsample and may suggest that females are more vulnerable to alcohol than males. Our findings lead to the conclusion that method of event related potential (P-300) may help in estimating organic deficit in alcoholic patients.

Three-dimensional finite element modeling of a cervical vertebra: an investigation of burst fracture mechanism.

Finite element modeling was used to study the mechanical behavior of a cervical vertebra under axial compressive loading. A three-dimensional (3-D) finite element (FE) model of a mid-cervical vertebra using inhomogeneous material properties was generated from quantitative computed tomographic (CT) scan data. This model improved upon previous vertebral FE models by using a highly refined mesh to represent the 3-D variation in material properties of vertebral bone. Traumatic loading of the vertebra was simulated by applying an axial compressive displacement through linear spring elements. Bone strength was computed from the CT scan data and compared with predicted stress. Based on the maximum shear stress theory of failure, the model predicts initiation of failure in the central cancellous region of the vertebral body. The type of fracture pattern predicted by the model is consistent with the typical cervical burst fracture that is seen clinically after compressive loading of the cervical spine. As such, we have developed a tool that can be useful for validating proposed fracture mechanisms in the cervical spine.

[Leber's optic atrophy (case report of progressive hereditary amaurosis]. / Leberova opticka atrofija (prikaz slucaja progresivne hereditarne amauroze).

This paper presents clinical findings of Leber's optic atrophy, a hereditary disorder, characterized by a progressive lost of vision. It points out to the validity of complex clinical, laboratory and neurophysiological investigations and excludes other diseases which by differential diagnosis may be taken into account.

[The effect of homocarnosine on neuronal activity during satiation and starvation]. / Dejstvo homocarnosina na aktivnost neurona u stanjima sitosti i gladovanja organizma.

We investigated effects of homocarnosine (gamma-aminobutyric-histidine) dipeptid on neuron nucleus caudatus and hypocampus activity in small and hungry experimental animals--awake grown-up rabbits. In the given conditions, through glass microelectrodes having several channels, an extracellular registration of impulse discharge was performed as well as the microapplication of homocarnosine (HC) in the immediate surroundings of registered neurons. The obtained results show that the investigated different functional conditions of the organism are manifested in the neurons' activity of the investigated brain structures. Homocarnosine represses the activity of most registered neurons in both satiated and hungry experimental animals, while that effect is more manifested in satiated animals. The demonstrated effects of homocarnosine point to its probable neuromediator role.