Biomedical subjects

Herman Kingma

Publications and source records attributed to Herman Kingma.

7 recordsLinked to original sources

PubMed2006

Function tests of the otolith or statolith system.

PURPOSE OF REVIEW: This review aims to provide an overview of recent advances in tests to evaluate otolith function over the last 2 years. RECENT FINDINGS: Over the last 2 years, many papers have focused on the application of the vestibular evoked myogenic potentials (VEMP). Several aspects are under survey: a search for optimal stimuli, search for normative data, search for which labyrinthine function losses and what kind of pathologies induce abnormal VEMPs. The review shows that some fundamental problems still have to be solved to improve reproducibility and to increase sensitivity. Other research and modelling is performed to find out how the brain distinguishes tilts from translations. Several papers support routine implementation of subjective visual vertical (SVV) measurements (in rest and during centrifugation) in the standard vestibular test battery. Interesting reports mention short latency vestibulo-ocular reflex induced by taps and short auditory stimuli. One report mentions the impact of otolith dysfunction upon spontaneous nystagmus and head shaking nystagmus. SUMMARY: Although validation is still needed and in progress, the state of the art laboratory should consider the following tests for an evaluation of otolith function as relevant: slow tandem gait, VEMP, SVV during centrifugation.

Animals↗

PubMed2004

Habituation to galvanic vestibular stimulation for analysis of postural control abilities in gymnasts.

The possible correlation between postural control abilities in gymnasts and the sensitivity for and the degree of short-term habituation to galvanic vestibular stimulation (GVS) was studied. Seven balance trained young girls (Dutch National Junior Gymnasts Championship) versus seven non-trained girls and twenty-five women underwent computer-controlled GVS using a monaural continuous 1-cosinusoidal stimulus of 0.5 Hz and 2 mA, repeated three times on each side [Balter, Stokroos, Boumans, Kingma, Acta Otolaryngol. (in press); Balter, Stokroos, Eterman, Paredis, Orbons, Kingma, Acta Otolaryngol. (in press)]. Results showed that mean total galvanic-induced body sway (GBS) gain was significantly lower in the trained and untrained girls compared to the adult women (P < 0.05). Mean habituation to GVS (learning abilities), however, showed no significant differences between the three groups. We suggest that the superior balance control in professional gymnasts is primarily achieved through motor training and not by learning abilities or a higher sensitivity of the vestibular system [Neurosci. Lett. 225 (1998) 155].

Adult↗

PubMed2004

Background on methods of stimulation in galvanic-induced body sway in young healthy adults.

The aim of this study was to develop a standardized procedure for reproducible quantification of galvanic-induced body sway (GBS). This was a prospective experimental study conducted in a tertiary referral centre. An exploratory study was first conducted to define the galvanic vestibular stimulation (GVS) method that resulted in the best reproducible responses. Ten subjects underwent computer-controlled GVS using five different types of monaural and binaural stimulation with 2-mA currents. Cosinusoidal stimulation gave the most reproducible responses. The frequency and current variability of this stimulus type were then tested in the same 10 subjects. A monaural continuous 1-cosinusoidal current of 0.5 Hz and 2 mA gave the most reproducible responses (< 20% test-retest variation) and the largest GBS amplitude. The other (sinusoidal) stimuli resulted in variabilities exceeding 50%. This stimulus was thus used for further testing in our normative study. In this study we measured GBS amplitude at 0.5 Hz in 60 subjects, with eyes closed and an inter-feet distance of 0 cm, using a force platform. In addition to body sway, responses included slight dizziness, taste sensations and a tingling sensation at the site of stimulation. Habituation to the applied stimulus was seen. Binaural prestimulation, performed in 50/60 test subjects, is necessary to reduce habituation and achieve optimal reproducibility in order to be able to compare the sensitivity of the left and right vestibular systems. The test-retest variability was determined in detail in 12 additional subjects. Prestimulation reduced habituation, but improved the sensitivity of the method; some test-retest variability persisted (< 20%).

Adult↗

PubMed2004

Galvanic-induced body sway in vestibular schwannoma patients: evidence for stimulation of the central vestibular system.

OBJECTIVE: To investigate the various possible sites of excitation by galvanic stimulation by comparing the galvanic-induced body sway (GBS) in vestibular schwannoma (VS) patients with that in healthy subjects. MATERIAL AND METHODS: This was a prospective experimental study conducted in a tertiary referral centre. In a previous study we developed a standardized procedure for reproducible quantification of GBS using a monaural continuous 1-cosinusoidal stimulus (0.5 Hz; 2 mA). In this study, 23 VS patients were tested before and 12 VS patients were also tested after surgical intervention (extirpation of tumour with concomitant vestibular neurectomy) and the results were compared with those obtained in 47 healthy subjects. RESULTS: There were no significant differences in mean total GBS gain between VS patients and healthy subjects (p>0.05) before surgical intervention. After vestibular neurectomy a significant difference in the mean total GBS gain was observed, but GBS was still present after surgery. CONCLUSION: These results prove that galvanic vestibular stimulation excites the central vestibular system even when conduction via the vestibular nerve is hampered.

Adult↗

PubMed2004

Selective vestibular ablation by intratympanic gentamicin in patients with unilateral active Ménière's disease: a prospective, double-blind, placebo-controlled, randomized clinical trial.

OBJECTIVE: To establish the efficacy of intratympanic gentamicin treatment in patients with unilateral Ménière's disease. MATERIAL AND METHODS: This was a prospective, double-blind, randomized clinical trial of intratympanic gentamicin versus intratympanic buffer solution (placebo) in patients with established active Ménière's disease in the affected ear. Outcome measures included the number of vertiginous spells, degree of sensorineural hearing loss, labyrinthine function and labyrinthine asymmetry. RESULTS: Topical gentamicin provided a significant reduction in the number of vertiginous spells, although a "placebo effect" was also observed. Sensorineural hearing loss did not occur in the gentamicin group, although some deterioration occurred in the placebo group. CONCLUSIONS: Intratympanic gentamicin is a safe and efficient treatment for the vertiginous spells associated with Ménière's disease. When applied early in the course of the disease, it may prevent some of the sensorineural hearing deterioration associated with it.

Adult↗

PubMed2004

Habituation to galvanic vestibular stimulation for analysis of susceptibility to carsickness.

OBJECTIVE: In a previous study we developed a standardized procedure for a reproducible quantification of galvanic-induced body sway (GBS). In line with other reports, GBS shows short-term (fast) habituation upon stimulus repetition. The aim of this study was to evaluate whether the degree of short-term habituation to galvanic vestibular stimulation (GVS) is correlated with susceptibility to carsickness. MATERIAL AND METHODS: A total of 24 female subjects underwent computer-controlled GVS as part of a prospective experimental study conducted in a tertiary referral center. A binaural 1-cosinusoidal stimulus of 0.5 Hz and 1 mA was repeated five times. Binaural stimulation was chosen to obtain maximum responses, making possible habituation to repetitive GVS obvious. The groups consisted of 12 subjects suffering from carsickness and 12 healthy subjects. RESULTS: Analysis of the repeated measurements test showed that the GBS-gain curve for the carsickness group was always superimposed on that for the healthy subjects. However, the (absolute) first to fifth GBS gains showed no significant differences (p = 0.134 - 0.995). When comparing short-term habituation in subjects suffering from carsickness versus healthy subjects, the results showed no differences in the mean values of the first (30.534% vs 27.024%), final (42.637% vs 38.544%) and average (35.544% vs 33.644%) habituations (p = 0.875, 0.991 and 0.951, respectively). CONCLUSION: We did not observe any significant differences in sensitivity or habituation of the GBS in carsick subjects compared to healthy subjects. This implies that carsick subjects show a similar ability to discard an irrelevant, non-motion sickness-inducing galvanic stimulus as healthy subjects.

Adult↗

PubMed2004

Habituation to galvanic vestibular stimulation.

OBJECTIVE: To examine the response decline that occurs upon repetitive galvanic vestibular stimulation (GVS) and hampers long-term clinical evaluations. MATERIAL AND METHODS: This was a prospective experimental study conducted in a tertiary referral centre. In a previous study we developed a standardized procedure for reproducible quantification of galvanic-induced body sway (GBS). The most reproducible responses were found using a continuous 1-cosinusoidal stimulus (0.5 Hz; 2 mA) preceded by a pre-habituating stimulus. This binaural prestimulation reduced the short-term (<5 min) response decline to a non-significant level. The response decline without prestimulation was interpreted as habituation to the galvanic stimulation. In the present study we evaluated possible long-term habituation to GVS, which may hamper longitudinal clinical evaluations. Possible long-term habituation using the short-term habituating prestimulus concept was studied by quantifying GBS in 40 subjects at 5 consecutive time points. Subjects were subdivided into four equal groups who were tested with four different time intervals between the five measurements, ranging from 1 day to 2 weeks. RESULTS: The absolute test results did not vary with the time interval (p=0.217; repeated measurement test). Irrespective of the time interval between the tests, habituation occurred after the first stimulation and remained stable at all consecutive measurements. GVS habituation did not depend on either the degree of daily life activity (moderate practice of sport) or on gender. CONCLUSION: The current protocol, using a prehabituating binaural stimulus, showed that reproducible assessment of the GVS over a time course of days to weeks was possible starting from the second test.

Adult↗