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Biomedical subjects

W J Oosterveld

Publications and source records attributed to W J Oosterveld.

At least 19 recordsLinked to original sources
PubMed1999

The effectiveness of piracetam in vertigo.

Vertigo is a sensation of altered orientation in space and may be defined as an illusion of movement. It is a subjective symptom and therefore difficult to assess. Examination and diagnosis remain difficult. Although treatment should be directed at the underlying cause or disorder, the origin of vertigo is frequently unknown or untreatable. Pharmacotherapy is required for symptomatic treatment. Piracetam has been shown to be effective in vertigo of both central and peripheral origin. It is thought to act on vestibular and oculomotor nuclei in the brain stem and thus on the central control of balance enhancing mechanisms of compensation and habituation. This review of double-blind trials shows that piracetam alleviates vertigo after head injury, vertigo of central origin as, for example, in vertebrobasilar insufficiency and in peripheral vestibular disorders, especially in middle-aged and elderly subjects. Piracetam decreases the frequency but probably not the severity of exacerbations in patients with chronic or recurrent vertigo. The usual dosage of piracetam in vertigo is 2.4-4.8 g daily. Tolerability of piracetam is good and adverse effects have been mild and infrequent.

Controlled Clinical Trials as Topic↗
PubMed1999

Behaviour of adult hamsters subjected to hypergravity.

We studied vestibular function in 20 adult hamsters (3 months old) subjected to either prolonged hypergravity (n = 10) or normal gravity (n = 10) for 2 months. Locomotion and swimming of the hypergravity hamsters under light conditions were normal. Equilibrium maintenance was severely disturbed; only 6 of 10 hypergravity hamsters managed to walk on the small tube after 2 months, whereas all 10 controls were able to walk on the tube. The air-righting reflex was severely disturbed; the hypergravity hamsters made 30% correct air-righting responses, while the control hamsters made 88% correct responses. Finally, 5 of 8 hypergravity hamsters had to be saved from drowning when swimming in total darkness. Histological examination of the utricular otoconial layers afterwards, using energy dispersive X-ray element (EDAX) analysis and scanning electron microscopy, did not reveal any differences in calcium content, shape and size distribution of the otoconia between hypergravity hamsters and controls. We suggest that adult hamsters adapt to hypergravity, leading to problems in normal functioning when tested in 1 G, especially in tasks in which sensory input of the vestibular system is important for spatial orientation. These disturbances were more severe in adult hamsters than in young ones, tested in previous experiments. Therefore, we assume that age is a factor for adaptation to altered gravity conditions.

Adaptation, Physiological↗
PubMed1998

Behavioural changes in hamsters with otoconial malformations.

For a period of 10 months, the perceptive-motor skills of golden hamsters were tested as part of an experiment to investigate vestibular controlled behaviour. We found that four out of 40 hamsters had more difficulties with swimming and equilibrium maintenance than the rest of the group. These disturbances either were apparent during the first months of testing or developed at a later period. In three hamsters the disturbances persisted over time while in one hamster performance in perceptive-motor skills increased. Histological examination with scanning electron microscopy revealed otoconial abnormalities in the saccule and/or the utricle. The otoconia were either malformed or replaced by spherulites. We conclude that the observed behavioural disturbances were caused by a defective peripheral vestibular organ. The results show similarities with data from pathology in other animals as well as in the human inner ear.

Animals↗
PubMed1997

Altered behaviour in hamsters conceived and born in hypergravity.

We studied vestibular function in 37 hamsters (1 month old) conceived and born in either hypergravity (n = 21) or normal gravity (n = 16). Four groups were made: (1) HL group: 20 weeks in 2.5 G and 14 weeks in 1 G; (2) HS group: 4 weeks in 2.5 G and 30 weeks in 1 G; (3) CON group: 34 weeks in 1 G; and (4) ROT group: 4 weeks in 1 G, 16 weeks in rotation in 1 G, at the centre of the centrifuge and 14 weeks 1 G. When the hamsters were 4 weeks old, their locomotor activity, swimming ability, and air-righting was assessed. We found that HL and HS hamsters had no disturbances during locomotion in 1 G but their swimming ability was disturbed (swimming underwater, circling, and decreased speed of swimming). The HL hamsters showed less activity during 2.5 G and showed fewer correct air-rightings than the other groups. Differences between groups in swimming ability and the number of correct air-righting responses remained even after 3 months of normal gravity. Based on these findings, we suggest that the persistent behavioural disturbances are caused by the embryonal development of the hamsters in a hypergravity environment. Furthermore, hypergravity and rotation each have a different effect on behaviour.

Age Factors↗
PubMed1996

Otoconial alterations after embryonic development in hypergravity.

The relation between prolonged hypergravity and structural adaptation of otoconia was studied in hamsters (n = 56). Three groups of hamsters (n = 27), were conceived and born in a centrifuge: group 1 (n = 10) 1 month under 2.5 G, group 2 (n = 9) 5 months under 2.5 G and 4 months under 1 G, group 3 (n = 8) 1 month under 2.5 G and 8 months under 1 G. Control hamsters (n = 29) were conceived and born under 1 G (1 month old, n = 7; 9 months old, n = 22). Histological study of the otoconial layers (energy dispersive x-ray element analysis and scanning electron microscopy) showed similar calcium content, size, and shape in utricular and saccular otoconia in all groups. Different were the utricular otoconial size classes, large, medium-sized, and small. The area with small otoconia increased in group 1 (p = 0.002). In group 2, the large otoconial area decreased (p = 0.001) and the medium-sized one increased (p < 0.001). In group 3, the large otoconial area decreased (p = 0.003) and the medium-sized one increased (p = 0.007). For age-related effects we found group 1 with an increased area of large otoconia (p = 0.001) and a decreased medium-sized one compared to groups 2 (p < 0.001) and 3 (p = 0.02). Hypergravity during formation of otoconia does not affect calcium content, size, or shape, but changes relative size of the areas with large, medium-sized, or small otoconia and the development of these areas. This resulted in a structural adaptation to hypergravity.

Animals↗
PubMed1996

Altered behaviour of hamsters by prolonged hypergravity: adaptation to 2.5 G and re-adaptation to 1 G.

We studied the functional adaptation process in 40 hamsters subjected to either prolonged hypergravity to normal gravity. Subadult golden hamsters (n = 20) exposed to a hypergravity condition of 2.5 G for 6 months were tested to investigate the effect of hyper gravity on the perceptive motor skills and compared with control hamsters (n = 20). The motor coordination of the hypergravity hamsters hardly changed; locomotion was normal and swimming was possible. Equilibrium maintenance was disturbed during the first 3 months as was shown by the higher crossing time (p < 0.001) and higher fall frequency (p < 0.001) for the hypergravity group. Significant differences were also found in orientation during swimming (p = 0.007) and turning behaviour in the rotation task (p < 0.001) and in the no-rotation task (p = 0.029). After 6 months, 10 hamsters of both groups were tested for another 4 months, also the hypergravity hamsters were living at 1 G. Differences in orientation in the two groups did not change during swimming and turning behaviour during the rotation task (p = 0.026). Based on our findings, we conclude that the hamsters functionally adapted to hypergravity, which led to an altered performance of several tasks. The condition continued after 4 months of normal gravity.

Animals↗
PubMed1996

Swimming behavior of fish during short periods of weightlessness.

BACKGROUND: Birds and fish show tumbling and spinning movements when subjected to short periods of weightlessness during parabolic flight. The reason for this behavior is not clear. HYPOTHESIS: The semicircular canal system is a rotation-detecting device; however, it seems that linear accelerations have an influence, too. Microgravity induces rotatory sensations which leads to a compensatory behavior (e.g., rotatory movements). METHODS: The swimming behavior of goldfish was studied with the fish in four different conditions: normal fish (group I); fish with one eye recently removed (group II); fish with both eyes recently removed (group III); and fish with both eyes removed 10 months previously (group IV). Further, a group of naturally blind (e.g., not surgically treated) cavefish (group V) were involved in the study also. All procedures conformed to the guiding principles as required in the Dutch Law on Care and Use of Animals. RESULTS: Three main different patterns of abnormal swimming behavior could be observed: tumbling (pitch), corkscrew movements (pitch and roll), and spinning movements (roll). NF did not shown any special swimming pattern. One-eyed fish (group II): mostly corkscrew movements (62%). Blind fish (group III): a mixture of the three movements (17, 22 and 25%). Blind fish (group IV): mostly spinning movements (20%). Cavefish (group V): tumbling (21%), corkscrew movements (12%) and spinning movements (58%). CONCLUSION: Vision is the dominant cue, explaining the behavior of normal goldfish. When vision is absent, the fish relies on vestibular information with respect to orientation. The swimming behavior is presumably caused by an attempt to compensate rotatory illusions. As all movements were shown in the planes of the vertical canals, we conclude that these canals play a dominant role when fish are deprived from proper otolith information.

Animals↗
PubMed1995

Effects of sustained acceleration on the morphological properties of otoconia in hamsters.

We investigated the effect of prolonged hypergravity on the otoconial layer of the maculae utriculi and the maculae sacculi in hamsters. The animals were placed in a centrifuge under conditions of 2.5 G, and remained there for 6 months. We then determined the calcium contents of the otoconia with energy dispersive X-ray element analysis, and recorded the size, shape and distribution of the otoconia. Scanning electron microscopy was used to make photos to determine the effects of hypergravity on the shape and size of the otoconia, and on the distribution of smaller and larger otoconia. No differences were found in the calcium content, shape, size or distribution of otoconia between centrifuged hamsters and control animals. Our findings indicate that structural adaptation to hypergravity does not take place at the otoconial level, at least not in animals subjected to hypergravity after the vestibular system was fully matured.

Animals↗
PubMed1994

[Otoneurologic disorders after cervical whiplash trauma].

An extensive vestibular examination was conducted in 462 patients suffering from the after-effects of a cervical whiplash trauma. Vertigo and dizziness were mentioned by 318 (68%) of the subjects, among a variety of other complaints. The examination revealed the existence of central-vestibular lesions in 258 (56%) of the patients.

Accidents, Traffic↗
PubMed1993

Effectiveness of sensory integration therapy on smooth pursuits and organization time in children.

In this study the effect of sensory integration (SI) therapy on smooth pursuit eye movements, tracking and learning time was evaluated in 21 children diagnosed with sensory integration dysfunction. A control group of 11 normal children, matched for age and sex was also tested. Electrooculograph (EOG) recordings were inspected for number of saccadic intrusions during smooth pursuit movements. Prior to therapy the children in the SI treatment group exhibited significantly more saccadic intrusions during smooth pursuit movements and took significantly longer to perform the task than the normal control group. After 6-9 months of SI therapy one hour a week, there was a significant reduction in the number of saccades in the treatment group. The treatment group demonstrated a reduction in the time necessary to accomplish smooth pursuits and organizational time. The etiology of these improvements may be related to the subcortical substrated utilized in SI therapy as well as in the generation of smooth pursuit eye movements.

Child↗
PubMed1991

The caloric vestibular nystagmus during short lasting microgravity.

In human subjects the caloric vestibular test was conducted during parabolic flight. The ear irrigation was performed from 35 secs. till 5 secs. before the onset of microgravity. Nystagmography covered a 10-minutes period, including three parabolic manoeuvres of the aircraft. a. The slow phase velocity (SPV) of the caloric nystagmus increased proportionally with the value of the g-force. Introduction of microgravity induced an exponential decrease of the SPV decay. b. The nystagmus disappeared completely in microgravity, but SPV decay showed a specific time constant. c. The averaged time constant values of the caloric nystagmus SPV decay after sudden onset of microgravity and the averaged time constant of the SPV decay following a sudden stop after sustained rotation during 0-g appeared to be on the same level (10.2 s. and 10.6 s.). d. These two averaged time constant values obtained during short lasting microgravity proved to be on a lower level than those time constants (15.5 secs.; 15.9 secs.) found in ground-based conditions. e. Because of the similarities in the characteristics of both SPV decay's and their accompanying time constants, a common working mechanism of cupular stimulation is likely. Most probably a fluid movement (or pressure) provokes a cupula deflexion followed by a cupula reflexion, either caused by a sudden stop after a sustained rotation or by a sudden onset of microgravity after g-load calorization. The present results support the Barany convection theory with regard the endolymph stimulatory properties following the caloric test.

Adult↗
PubMed1991

Current diagnostic techniques in vestibular disorders.

Vestibular disorders provoke complaints in patients, affecting daily life sometimes seriously. A systematic approach to elicit a patient's medical history ensures a broad assessment of each individual since vertigo can be caused by a lesion in any part of the vestibular or nervous system. Vestibular test programmes date as far back as 1850. Both vestibulo-spinal and vestibulo-ocular tests have been developed since then. The most recent ones provide the investigator with extremely sophisticated information. Electron stagmography offers the opportunity of gaining insight into the visual pursuit system, which adds considerable value to the whole test battery. Current diagnostics of the vestibular system partly deals with neurophthalmology as far as all aspects of ocular motility are concerned.

Eye Movements↗
PubMed1991

Electronystagmographic findings following cervical whiplash injuries.

A group of 262 patients suffering from the after-effects of an acceleration trauma of the neck were subjected to an extensive vestibular examination. 85% of the patients complained of some type of vertigo. The visual suppression test conducted during rotation showed pathology in 37% of the cases. Visual pursuit movements were affected in 43% of the cases. In a group of 41 patients the results obtained respectively 1 and 2 years after the accident were compared. There was no significant improvement of the findings. No oculomotor system pathology was found in 99 cases (38%), and no electronystagmographic pathology at all in 55 cases (21%). The study emphasized the fact that nystagmographic examinations are able to detect central vestibular dysfunction and is therefore a suitable method to prove pathology.

Adolescent↗
PubMed1988

Vertical nystagmus provoked by locally applied calorization at the vertical semicircular canals: a study in pigeons.

Calorization of the vertical semicircular canals in pigeons was performed by irrigation of water through a polyethylene cannula, that was attached at a selected site to the bony wall of the anterior or posterior canal of the labyrinth. The temperature differences between the stimulated site and the corresponding location inside the contralateral mastoid were detected by two thermistors. (a) Calorization of an anterior or posterior canal evoked a dissociated vertical nystagmus in both eyes. (b) The direction of the nystagmus and of the vertical slow phase velocity proved to be temperature-dependent. (c) The vertical eye movements disappeared when the stimulated canal was placed horizontally during calorization. (d) During parabolic flight the vertical and horizontal eye movements, elicited by sustained calorization, disappeared during short periods of microgravity and proved to be dependent to the g load. (e) All vertical canal calorizations evoked eye movements in the plane parallel to the stimulated canal. Left and right eye moved in opposite vertical directions, depending on the selected site of calorization on the vertical canal. (f) The same mode (warm or cold) of calorization of an anterior canal provoked similar vertical movements of both eyes as compared to the vertical eye movements that were induced by calorization of the contralateral posterior canal. The results are discussed in view of the 'convection current' and the 'expansion/contraction' theory and they are compared to previously reported results of vestibular nerve stimulation.

Animals↗