Joint and individual effectiveness of galvanic cutaneous stimulation and tactile stimulation at decreasing Simulator Adaptation Syndrome.

This research was focused on investigating the effectiveness of galvanic cutaneous stimulation and tactile stimulation jointly and individually at mitigating Simulator Adaptation Syndrome. Forty drivers (mean age = 23.1 ± 3.4 years old, twenty women) participated in a driving simulation experiment. Total scores of the Simulator Sickness Questionnaire, head movements (an index of body balance), and driving performance variables were compared across four different stimulation conditions: i) baseline (where no stimulation was presented), ii) galvanic cutaneous stimulation and iii) tactile stimulation deployed individually, and iv) both techniques deployed jointly. The results showed that both techniques presented in conjunction alleviate Simulator Adaptation Syndrome and improve driving performance more effectively than when they are presented in isolation. Importantly, reduced head movements were only revealed when galvanic cutaneous stimulation was applied. We concluded that the reduction of this syndrome is due to an improvement of body balance (elicited by galvanic cutaneous stimulation), and a distraction from the symptoms (elicited by tactile stimulation). We encourage the use of both techniques simultaneously to decrease Simulator Adaptation Syndrome.

Effect of exposure to short-wavelength light on susceptibility to motion sickness.

This randomized cross-over study tested the hypothesis that exposure to short-wavelength light induces symptoms of motion sickness (MS). The study participants were 28 healthy adults (14 women; mean age±SD, 25.96±3.11 years). Two stimuli oscillating within a range of 0.4-0.6 Hz were used to induce MS: a blue wave stimulus with short-wavelength light (460 nm) and a green wave stimulus with middle-wavelength light (555 nm). All participants were exposed to both stimuli throughout two separate periods. After a baseline period, participants were exposed to each stimulus three times for 4 min. The Simulator Sickness Questionnaire, a self-report checklist composed of three subscales (Oculomotor, Disorientation, and Nausea), heart rate variability, and electrogastrography were used to measure the degree of symptoms related to MS. A linear mixed-effects model was used for statistical analysis. The results showed significant main effects for Period (P<0.01), Color (P<0.01), and Time Point (P<0.01) scores on the Simulator Sickness Questionnaire Nausea subscale. A post-hoc test indicated that scores on the Nausea subscale were significantly higher after the third exposure to blue light than after the first and second exposures. The linear mixed-effects model showed significant main effects for Color (P<0.01) with respect to the normogastria/tachygastria ratio. These findings suggest that short-wavelength light induces symptoms of MS, especially gastrointestinal symptoms.

Sea State Green.

The series objective is to review various clinical conditions/ presentations, including the latest evidence on management, and to dispel common myths. In the process, core knowledge and management principles are enhanced. A clinical case will be presented. Cases will be drawn from real life but phrased in a context that is applicable to the Special Operations Forces (SOF) or tactical emergency medical support (TEMS) environment. Details will be presented in such a way that the reader can follow along and identify how they would manage the case clinically depending on their experience and environment situation. Commentary will be provided by currently serving military medical technicians. The medics and author will draw on their SOF experience to communicate relevant clinical concepts pertinent to different operational environments including SOF and TEMS. Commentary and input from active special op.

[Modern means of statokinetic improvement and vestibular rehabilitation].

The article presents the results of studying the effectiveness of the complex vestibular workouts based on non-invasive neuromodulation technology in 37 healthy patients aged 18-20 years who have symptoms of aerial sickness in 5 or less minutes. Non-invasive neuromodulation wire-familiarize with the apparatus for vestibular rehabilitation "Brain-Port" (USA), performing electric tactile stimulation of the tongue with biofeedback. An indicator of statokinetic stability was considered from time to tolerance to the vestibular load up to development of vegetative manifestations of aerial sickness. 'Improvement of statokinetic tolerability vestibular training confirmed by computed posturography and gait analysis. Increase of statokinetic stability accompanied not only by an increase in exposure, necessary for motion sickness, but also a decrease in autonomic manifestations, which are the main obstacle to the operator's military activities. Improving balance and gait performance after the swipe-of vestibular training course demonstrates the possible realization of two mechanisms of compensatory and restorative processes: sensory substitution equilibrium function and induction of neuroplasticity in short time.

A Medical Food Formulation of Griffonia simplicifolia/Magnesium for Childhood Periodic Syndrome Therapy: An Open-Label Study on Motion Sickness.

Motion sickness (MS) is a disabling condition dominated by disagreement between visually perceived movement and the vestibular system's sense of movement, with symptoms like dizziness, fatigue, and nausea, and other autonomic disabling symptoms. Preparations of Griffonia simplicifolia, containing high concentrations of 5-HTP, might be effective for serotonin-related disorders, including MS. Therefore, the aim of the present study is to assess the efficacy and safety of the G. simplicifolia/magnesium complex in a pediatric population with MS. The Griffonia/magnesium complex (50 and 200 mg, respectively) was orally administered as a prophylactic therapy for MS twice a day for 3 months to group A, and no therapy for MS was administered to group B. The MS clinical signs were recorded by parents or, where possible, directly from children by a specific module, which included validated questions for the diagnoses that were administered to all subjects and parents of both groups. Two study groups were matched for age (P=.224), sex (P=.801), and z-score body-mass index (P=.173). At T0, all recruited subjects in both groups complained about MS. After 3 months (T1), group A showed an MS prevalence of 36%, significantly lower than MS prevalence in group B (73%) (P<.001). The findings of the present study suggest the role of the Griffonia/magnesium complex as a potential treatment with middle-term efficacy even for MS.

Demonstrating the potential for dynamic auditory stimulation to contribute to motion sickness.

Auditory cues can create the illusion of self-motion (vection) in the absence of visual or physical stimulation. The present study aimed to determine whether auditory cues alone can also elicit motion sickness and how auditory cues contribute to motion sickness when added to visual motion stimuli. Twenty participants were seated in front of a curved projection display and were exposed to a virtual scene that constantly rotated around the participant's vertical axis. The virtual scene contained either visual-only, auditory-only, or a combination of corresponding visual and auditory cues. All participants performed all three conditions in a counterbalanced order. Participants tilted their heads alternately towards the right or left shoulder in all conditions during stimulus exposure in order to create pseudo-Coriolis effects and to maximize the likelihood for motion sickness. Measurements of motion sickness (onset, severity), vection (latency, strength, duration), and postural steadiness (center of pressure) were recorded. Results showed that adding auditory cues to the visual stimuli did not, on average, affect motion sickness and postural steadiness, but it did reduce vection onset times and increased vection strength compared to pure visual or pure auditory stimulation. Eighteen of the 20 participants reported at least slight motion sickness in the two conditions including visual stimuli. More interestingly, six participants also reported slight motion sickness during pure auditory stimulation and two of the six participants stopped the pure auditory test session due to motion sickness. The present study is the first to demonstrate that motion sickness may be caused by pure auditory stimulation, which we refer to as "auditorily induced motion sickness".

Galvanic vestibular stimulation: a novel modulatory countermeasure for vestibular-associated movement disorders.

Motion sickness or kinetosis is the result of the abnormal neural output originated by visual, proprioceptive and vestibular mismatch, which reverses once the dysfunctional sensory information becomes coherent. The space adaptation syndrome or space sickness relates to motion sickness; it is considered to be due to yaw, pith, and roll coordinates mismatch. Several behavioural and pharmacological measures have been proposed to control these vestibular-associated movement disorders with no success. Galvanic vestibular stimulation has the potential of up-regulating disturbed sensory-motor mismatch originated by kinetosis and space sickness by modulating the GABA-related ion channels neural transmission in the inner ear. It improves the signal-to-noise ratio of the afferent proprioceptive volleys, which would ultimately modulate the motor output restoring the disordered gait, balance and human locomotion due to kinetosis, as well as the spatial disorientation generated by gravity transition.

Galvanic vestibular stimulation: a novel modulatory countermeasure for vestibular-associated movement disorders / Estimulacao galvanica vestibular para corrigir transtornos neurologicos associados a disfuncao vestibular

Motion sickness or kinetosis is the result of the abnormal neural output originated by visual, proprioceptive and vestibular mismatch, which reverses once the dysfunctional sensory information becomes coherent. The space adaptation syndrome or space sickness relates to motion sickness; it is considered to be due to yaw, pith, and roll coordinates mismatch. Several behavioural and pharmacological measures have been proposed to control these vestibular-associated movement disorders with no success. Galvanic vestibular stimulation has the potential of up-regulating disturbed sensory-motor mismatch originated by kinetosis and space sickness by modulating the GABA-related ion channels neural transmission in the inner ear. It improves the signal-to-noise ratio of the afferent proprioceptive volleys, which would ultimately modulate the motor output restoring the disordered gait, balance and human locomotion due to kinetosis, as well as the spatial disorientation generated by gravity transition.

A cinetose ou doença do movimento resulta de uma resposta neural anormal originada do desequilíbrio entre estímulos visuais, proprioceptivos e vestibulares, que melhora quando esse desequilíbrio é corrigido. A síndrome de adaptação espacial ou doença do espaço está relacionada à doença do movimento e é desencadeada por mudanças bruscas de direção, inclinação e rotação da cabeça. Têm sido propostas várias medidas comportamentais e farmacológicas para controlar esses transtornos do movimento associados com o sistema vestibular, mas sem sucesso. A estimulação galvânica vestibular pode regular o desequilíbrio sensitivo-motor causado pela cinetose e pela doença do espaço modulando os canais iônicos GABA, relacionados à transmissão de impulsos nervosos no ouvido interno. Essa estimulação melhora a relação sinal-ruído dos impulsos proprioceptivos que acabam modulando a resposta motora, restabelecendo o equilíbrio e a marcha, recuperando a desorientação espacial causada pelos diversos gradientes de gravidade.

Effects of transcutaneous electrical nerve stimulation on motion sickness induced by rotary chair: a crossover study.

OBJECTIVES: Motion sickness (MS) is evoked by the conflict among somatosensory, visual, and vestibular input. Some of the MS symptoms and signs are mediated by activation of the autonomic nervous system (ANS). Transcutaneous electrical nerve stimulation (TENS), a maneuver used for pain control, was found to influence cardiovascular responses through ANS reflex, and to enhance motor function, visuospatial abilities, postural control, and cognitive function. The purpose of the present study is to investigate the effects of TENS on MS. SUBJECTS AND DESIGN: Fifteen (15) healthy young men participated in a within-subjects crossover study. Each completed four test sessions (control, rotation, TENS, TENS+rotation) in randomized order. Rotary chair (120°/s) combined with pitch movement of the subject's head was used as a model to provoke MS. Whole rotation protocol consisted of 5 1-minute rotations, each separated by a 1-minute rest period. TENS protocol involved simultaneous electrical stimulation of posterior neck and Zusanli acupoint. OUTCOME MEASURES: Motion sickness susceptibility was rated on a standardized questionnaire (Motion Sickness Susceptibility Questionnaire). Motion sickness symptoms, blood pressure (BP), skin temperature, heart rate (HR), and heart rate variability (HRV) were measured. Saliva samples were collected to analyze the level of stress markers. Cognitive function was evaluated with d2 test prior to and after MS provocation. RESULTS: Spinning by itself significantly decreased task response speed and contraction. MS symptom scores, BP, as well as the sympathetic parameter of HRV increased progressively with MS provocation (p<0.05), but skin temperature decreased (p=0.023). Severity of MS symptoms significantly decreased with TENS intervention (p<0.05). After TENS treatment, subjects were able to concentrate better and showed fewer errors in a cognitive test. Salivary cortisol concentration significant decreased after TENS treatment. CONCLUSIONS: Sympathetic activity increased but parasympathetic activity decreased during MS. TENS was effective in reducing MS symptoms as well as alleviating cognitive impairment.

Migraine, vertigo and migrainous vertigo: Links between vestibular and pain mechanisms.

This review develops the hypothesis that co-morbid balance disorders and migraine can be understood as additive effects of processing afferent vestibular and pain information in pre-parabrachial and pre-thalamic pathways, that have consequences on cortical mechanisms influencing perception, interoception and affect. There are remarkable parallel neurochemical phenotypes for inner ear and trigeminal ganglion cells and these afferent channels appear to converge in shared central pathways for vestibular and nociceptive information processing. These pathways share expression of receptors targeted by anti-migraine drugs. New evidence is also presented regarding the distribution of serotonin receptors in the planum semilunatum of the primate cristae ampullaris, which may indicate involvement of inner ear ionic homeostatic mechanisms in audiovestibular symptoms that can accompany migraine.

Effects of hypergravity on histamine H1 receptor mRNA expression in hypothalamus and brainstem of rats: implications for development of motion sickness.

CONCLUSION: The study findings suggest that histamine was released from the axon terminals in the hypothalamus and brainstem and the released histamine activated post-synaptic H1 receptors there, resulting in the development of motion sickness. OBJECTIVES: We first examined which subtype of post-synaptic histaminergic receptor was responsible for the development of motion sickness. We then examined whether H1 receptors were up-regulated in various areas of the rat brain after 2 G hypergravity load, because the stimulation of H1 receptor was reported to up-regulate the level of H1 receptor protein expression through augmentation of H1 receptor mRNA expression. MATERIALS AND METHODS: For this purpose, we used an animal model of motion sickness, using pica (eating non-nutritive substances such as kaolin), as a behavioral index in rats. RESULTS: After 2 G hypergravity load, rats ate a significant amount of kaolin, indicating that they suffered from motion sickness. The hypergravity-induced kaolin intake was suppressed by mepyramine, but not by terfinadine or zolantizine. This finding indicates that cerebral post-synaptic H1 but not H2 or peripheral H1 receptors play an important role in the development of motion sickness. The expression of H1 receptor mRNA was up-regulated in the hypothalamus and brainstem, but not in the cerebral cortex after 2 G hypergravity load in rats.

[Effect of swinging on EEG of rats of juvenile age in the wakefulness state].

Simultaneous recording of the EEG activity of superficial cortical and deep (caudate nucleus, dorsal hippocampus, anterior hypothalamus) brain parts has been performed for the first time after a 2-h swinging of frequency of 0.2 Hz in Wistar rats of juvenile age. Swinging was produced on a 4-bar parallel swing. Using a Neuron-Spectr electroencephalograph and a Diana program, normalized power spectra of wave EEG components, synchronization coefficients, and coefficients of cross-correlation between bioelectrical potentials of various brain structures were determined. After a 2-h swinging, the mean value of normalized power of slow waves of delta-diapason in hypothalamus and hippocampus was found to increase statistically significantly, while normalized power of fast waves of alpha- and beta1-diapasons in hippocampus decreased (p < 0.05). A statistically significant increase of synchronization coefficient was observed in hypothalamus and hippocampus. Changes of coefficients of cross-correlation between hypothalamus and hippocampus and other brain strictures were of the oppositely directed, individual character. In the parietal occipital brain cortex and in caudate nucleus, the changes of the EEG spectral composition also were of individual character. The obtained results on the whole correspond to data about an enhancement of the EEG low-frequency rhythms at swinging and agree with the resonance hypothesis of motion sickness.

Psychophysiological correlates of the inter-individual variability of head movement control in seated humans.

We recently conducted experiments where 24 seated participants were subjected (with eyes closed) to small amplitude, high-jerk impulses of linear acceleration. Responses were distributed as a continuum between two extremes. The "stiff" participants showed little movement of the head relative to the trunk, whereas the "floppy" participants showed a large head rotation in the direction opposite the sled movement. We hypothesized that the stiff behavior resulted from the spontaneous use of an imagined visual frame of reference and undertook this larger-scale study to test that idea. The distribution along the "stiff-floppy" continuum was compared with the scores on psychophysiological tests measuring vividness of imagery, visual field-dependence and motion sickness susceptibility. Multivariate regression analysis revealed that the "stiffness" of individuals was loosely, but significantly related to the vividness of their imagery. However, "stiffness" was not linked to visual field-dependence or motion sickness susceptibility. Even if it explains only 20% of the variance of the data, the increase of "stiffness" with vividness of imagery fits our hypothesis. With eyes closed, stiff people may use imagined external visual cues to stabilize their head and trunk. Floppy people, who are poorer imagers, may rely more on "egocentric", proprioceptive and vestibular inputs.

P6 acupressure increases tolerance to nauseogenic motion stimulation in women at high risk for PONV.

PURPOSE: In a previous study we noticed that P6 acupressure decreased postoperative nausea and vomiting (PONV) more markedly after discharge. As motion sickness susceptibility is increased by, for example, opioids we hypothesized that P6 acu-pressure decreased PONV by decreasing motion sickness susceptibility. We studied time to nausea by a laboratory motion challenge in a group of volunteers, during P6 and placebo acupressure. METHODS: 60 women with high and low susceptibilities for motion sickness participated in a randomized and double-blind study with an active P6 acupressure, placebo acupressure, and a control group (n = 20 in each group). The risk score for PONV was over 50%. The motion challenge was by eccentric rotation in a chair, blindfolded and with chin to chest movements of the head. The challenge was stopped when women reported moderate nausea. Symptoms were recorded. RESULTS: Mean time to moderate nausea was longer in the P6 acu-pressure group compared to the control group. P6 acupressure = 352 (259-445), mean (95% confidence interval) in seconds, control = 151 (121-181) and placebo acupressure = 280 (161-340); (P = 0.006). No difference was found between P6 and placebo acupressure or placebo acupressure and control groups. Previous severity of motion sickness did not influence time to nausea (P = 0.107). The cumulative number of symptoms differed between the three groups (P < 0.05). Fewer symptoms were reported in the P6 acupressure compared to the control group P < 0.009. Overall, P6 acupressure was only marginally more effective than placebo acupressure on the forearms. CONCLUSION: In females with a history of motion sickness P6 acu-pressure increased tolerance to experimental nauseogenic stimuli, and reduced the total number of symptoms reported.

[Construction of the subtracted cDNA library in hypothalamus of the seasickness adaptive rats].

OBJECTIVE: To construct subtracted cDNA library in hypothalamus of the seasickness adaptive rats for providing theoretical basis for effective adaptive training against seasickness. METHODS: Suppression subtract hybridization technique was used, and forward and reverse hybridization was performed on the hypothalamus of seasickness adaptive rats and that of normal rats so that to construct subtracted cDNA library. Dot blot was used for differential screening the subtracted library. RESULTS: 23 fragments of differentially expressed genes was obtained including 10 up-regulating and 13 down-regulating fragments. CONCLUSION: Many played role in adaptability formation to seasickness such as SAM, vasopressin, and heme oxygenase.

Effects of intestinal electrical stimulation on intestinal dysrhythmia and symptoms in dogs.

The aim of this study was to investigate the effect of intestinal electrical stimulation on small intestinal dysrhythmia and motion sickness-like symptoms induced by vasopressin. Female dogs chronically implanted with two pairs of electrodes on jejunum serosa were used in a four-session study. Saline and vasopressin were infused in sessions 1 and 2, respectively. Sessions 3 and 4 were the same as session 2, except a long- or short-pulse intestinal electrical stimulation was applied on the proximal pair of electrodes. Intestinal slow waves and motion sickness-like symptoms were recorded in each session. Results were as follows. (1) Vasopressin induced intestinal dysrhythmia, uncoupling of slow waves, and vomiting and motion sickness-like symptoms (P < 0.05, ANOVA). (2) Intestinal electrical stimulation with long pulses, but not short pulses, was capable of preventing vasopressin-induced intestinal dysrhythmia. (3) Intestinal electrical stimulation with short pulses, but not long pulses, prevented vomiting and the motion sickness-like symptoms. It is concluded that vasopressin induces intestinal dysrhythmia. Long-pulse intestinal stimulation normalizes vasopressin-induced intestinal slow-wave abnormalities with no improvement in symptoms. Short-pulse stimulation prevents emetic symptoms induced by vasopressin but has no effect on slow waves. These data suggest different mechanisms involved with different methods of intestinal stimulation.

Effects of ginger on motion sickness and gastric slow-wave dysrhythmias induced by circular vection.

Ginger has long been used as an alternative medication to prevent motion sickness. The mechanism of its action, however, is unknown. We hypothesize that ginger ameliorates the nausea associated with motion sickness by preventing the development of gastric dysrhythmias and the elevation of plasma vasopressin. Thirteen volunteers with a history of motion sickness underwent circular vection, during which nausea (scored 0-3, i.e., none to severe), electrogastrographic recordings, and plasma vasopressin levels were assessed with or without ginger pretreatment in a crossover-design, double-blind, randomized placebo-controlled study. Circular vection induced a maximal nausea score of 2.5 +/- 0.2 and increased tachygastric activity and plasma vasopressin. Pretreatment with ginger (1,000 and 2,000 mg) reduced the nausea, tachygastria, and plasma vasopressin. Ginger also prolonged the latency before nausea onset and shortened the recovery time after vection cessation. Intravenous vasopressin infusion at 0.1 and 0.2 U/min induced nausea and increased bradygastric activity; ginger pretreatment (2,000 mg) affected neither. Ginger effectively reduces nausea, tachygastric activity, and vasopressin release induced by circular vection. In this manner, ginger may act as a novel agent in the prevention and treatment of motion sickness.

Postural dynamics: clinical and empirical implications.

OBJECTIVE: To provide a rationale for the examination of posture from a dynamic (behavioral) perspective and to relate the vertebral subluxation to postural instability and motion sickness via inefficiency. DATA COLLECTION: A manual search of available reference texts and a computer search of literature from Index Medicus, PsycINFO, and ISI Science Citation Index Expanded were collected with an emphasis on postural dynamics, vertebral subluxation, and motion sickness. RESULTS: Evidence linking behavioral and health research has emerged from the study of posture and postural dynamics. Studies examining the relation between postural control and motion sickness have shown that motion sickness is preceded and predicted by postural instability. Motion sickness is characterized by maladaptive response to unusual motion events. The symptoms are nonspecific and variable. Although the Postural Instability theory of motion sickness predicted that instability should precede sickness, it did not make any claims regarding the symptoms associated with it. Chiropractic literature has emphasized the effects of vertebral subluxation on neurologic dysfunction. Vertebral subluxation is a condition that is postulated to interfere with neurologic processes and may influence organ system function and general health. As in the case of motion sickness, symptoms are nonspecific and variable (and in some instances the person may have no symptoms). So what do these disorders have in common? In each instance the disruptions lead to inefficiency in the system. CONCLUSION: Given this potential commonality, we propose that some of the methods used by behavioral researchers to study postural dynamics may also be of great utility to health care practitioners and psychologists alike. Furthermore we propose that this link will provide a framework that will allow scientists to address seemingly intractable problems such as motion sickness or subluxation.

Effects of Command and Control Vehicle (C2V) operational environment on soldier health and performance.

The purpose of this project was to use NASA technology to assist the US Army in the assessment of motion sickness incidences and effects on soldier performance and mood states within the Command and Control Vehicle (C2V). Specific objectives were (1) to determine if there was a significant difference between three internal configurations of the C2V and/or between seats within these vehicles; (2) to determine if there was a significant difference between the park, move, or short-halt field conditions; and (3) to validate a method of converging indicators developed by NASA to assess environmental impact of long duration spaceflight on crewmembers, using a large sample of subjects under ground-based operational conditions.