The effect of meals of varying nutritional composition on subjective and physiological markers of nausea in response to optokinetic motion.

BACKGROUND: Protein ingestion has been shown to decrease subjective and physiological markers of nausea. AIM: To elucidate the importance of drink palatability and nutritional composition in preventing subjective symptoms of nausea, decreased normal gastric electrogastrographic activity, and withdrawal of vagal tone in response to optokinetic motion. METHODS: Participants received a liquid high protein/low carbohydrate, moderate protein/high carbohydrate, low protein/high carbohydrate or water meal 30 min prior to exposure to an optokinetic drum. Subjective symptoms of nausea, electrogastrograms and cardiac vagal tone were measured during the 30-min post-drink rest period, a 10-min baseline period in the stationary drum, and during a 16-min drum rotation period. RESULTS: Regardless of nutritional composition, a pleasant taste predicted a reduction of the subjective experience of nausea. Subjective symptoms were significantly more severe in the moderate protein/high carbohydrate and water groups compared to the high protein/low carbohydrate and low protein/high carbohydrate groups. Electrogastrographic indicators of nausea were reduced in the high protein/low carbohydrate and low protein/high carbohydrate groups versus water, while cardiac vagal tone was reduced in the high protein/low carbohydrate and moderate protein/high carbohydrate groups versus the low protein/high carbohydrate and water groups. CONCLUSIONS: Palatability and high protein meals appear to be important factors in attenuating the nausea associated with exposure to optokinetic motion.

Electrogastrographic biofeedback: a technique for enhancing normal gastric activity.

Biofeedback has been used effectively for approximately 40 years as a technique to help individuals learn to control muscle activity, brain waves, certain autonomic nervous system responses such as heart rate and blood pressure, and, more recently, constipation and fecal and urinary incontinence. In the present study, biofeedback of electrogastrographic (EGG) activity was used to determine the extent to which healthy subjects could increase normal 3 cpm gastric myoelectric activity. Thirteen experimental participants were provided with biofeedback of their EGG activity on a computer screen, and instructed to try to make their own EGG signal match a simulated 3 cpm signal that was also present on the screen. Subjects were told to relax using various forms of imagery, and to heighten their awareness of their stomach activity. Thirteen control participants did not receive any biofeedback but were otherwise given the same instructions. Both groups showed an increase in 3 cpm activity while relaxing. However, over four trials separated by 2-7 days, experimental participants showed an increased percentage of 3 cpm activity during biofeedback sessions, while control participants showed a decrease in 3 cpm activity during the corresponding sessions. In conclusion, we have demonstrated that healthy subjects can increase their normal gastric 3 cpm activity with the use of EGG biofeedback.

Protein-predominant meals inhibit the development of gastric tachyarrhythmia, nausea and the symptoms of motion sickness.

BACKGROUND: Meal ingestion has been suggested to reduce susceptibility to the development of gastric tachyarrhythmia, the abnormal activity of the stomach that frequently accompanies nausea. AIM: To determine the types of meal that are most effective in preventing the development of gastric tachyarrhythmia, nausea and the symptoms of motion sickness provoked by a rotating optokinetic drum. METHOD: Participants received a carbohydrate beverage, a protein-predominant beverage or nothing immediately before exposure to the rotating drum. Subjective symptoms of motion sickness and electrogastrograms were collected during a 6-min baseline period and a subsequent 16-min drum rotation period. RESULTS: Subjective symptoms of motion sickness scores were significantly more severe during the no-meal condition than during either the protein or carbohydrate condition. Central, peripheral and, to some extent, gastrointestinal symptoms were more severe during the carbohydrate condition than during the protein condition. Gastric tachyarrhythmia increased significantly less from baseline to drum rotation during both the protein and carbohydrate conditions than during the no-meal condition. CONCLUSIONS: Liquid protein-predominant meals were most effective in suppressing both the development of gastric tachyarrhythmia and the entire spectrum of motion sickness symptoms, including nausea.

The psychophysiology of nausea.

Nausea is an unpleasant sensation usually referred to the stomach and sometimes followed by vomiting. Little is known about the subjective aspects of nausea because like pain and fatigue, it is a private sensation. We conceive of nausea as a complex control mechanism that signals us when not to eat. Our research in the areas of motion sickness and chemotherapy has led us to propose that we each have a dynamic threshold for nausea, which depends on the interaction of inherent factors and more changeable psychological factors, and that this threshold effects the individual's cognitive appraisal of both the nauseogenic stimulus and his/her bodily change in response to the nauseogenic stimulus. Inherent factors that are described are age, gender and race; psychological factors that are included are anxiety, expectation, anticipation and adaptation. The physiological responses that have been found to accompany nausea include an increase in sympathetic nervous system activity, a decrease in parasympathetic activity, an increase of abnormal dysrhythmic gastric activity, and an increase in plasma vasopressin. It is concluded that beneficial selective reduction of nausea will depend on a greater knowledge of the interaction of the psychological and physiological variables.

Acupressure relieves the symptoms of motion sickness and reduces abnormal gastric activity.

CONTEXT: Acupuncture at the P6 or Neiguan point to treat nausea and vomiting has been practiced in China for many years. More recently, acupressure at P6 has been used successfully to decrease the symptoms of pregnancy sickness and with mixed results to decrease motion sickness. OBJECTIVE: To determine whether an Acuband, a commercially available acupressure wristband, would relieve the symptoms of motion sickness. METHOD: 25 healthy subjects, aged 18 to 22 years, prescreened for susceptibility to motion sickness, were tested on 3 separate occasions in a rotating optokinetic drum with the following conditions: wearing an Acuband on the wrist, wearing an Acuband on the arm, and wearing no Acuband. MAIN OUTCOME MEASURES: Subjective symptoms of motion sickness and abnormal gastric activity, as recorded via electrogastrography, were obtained throughout the procedure. RESULTS: Subjects reported significantly fewer symptoms of motion sickness on days when wearing the Acuband on the wrist or the arm than they did on control days (when they wore no Acuband). Subjects also showed less abnormal gastric activity on the days when wearing an Acuband than they did on control days. CONCLUSION: An Acuband worn on the wrist or forearm decreases the symptoms of motion sickness and the gastric activity that usually accompanies motion sickness.

Gastric myoelectrical and autonomic cardiac reactivity to laboratory stressors.

We evaluated the effects of two laboratory stressors (speech preparation and isometric handgrip) on gastric myoelectrical and autonomic cardiac activity, and the extent to which autonomic responses to these stressors and somatization predict reports of motion sickness during exposure to a rotating optokinetic drum. Both stressors prompted a decrease in preejection period (PEP) and respiratory sinus arrhythmia (RSA), and an increase in a dysrhythmic pattern of gastric myoelectrical activity, termed gastric tachyarrhythmia. Stressor-induced decreases in RSA and higher somatization scores predicted increased reports of motion sickness during drum rotation. These results demonstrate that laboratory stressors concurrently affect gastric myoelectrical activity and autonomic control of the heart, and that stressor-induced decreases in RSA and higher levels of somatization predict motion sickness susceptibility.

Relationship of gastric myoelectrical and cardiac parasympathetic activity to chemotherapy-induced nausea.

OBJECTIVES: We evaluated (a) whether pretreatment levels of gastric tachyarrhythmia, a dysrhythmic pattern of gastric myoelectrical activity, or cardiac parasympathetic activity are associated with the development of chemotherapy-induced nausea and (b) whether chemotherapy-induced nausea is preceded by an increase in gastric tachyarrhythmia and a decrease in cardiac parasympathetic activity, as has been observed during motion sickness. METHODS: Electrogastrograms and estimates of respiratory sinus arrhythmia (RSA) were obtained from cancer chemotherapy patients before treatment and for approximately 24 hours after treatment. RESULTS: Higher levels of pretreatment gastric tachyarrhythmia were observed on chemotherapy sessions that were followed by posttreatment reports of nausea. Pretreatment levels of RSA, however, did not differ between chemotherapy treatments that were and were not followed by nausea. No statistically significant changes in gastric tachyarrhythmia or RSA were observed prior to first reports of nausea following chemotherapy. CONCLUSIONS: In contrast to motion sickness, chemotherapy-induced nausea may not be related to an increase in dysrhythmic gastric myoelectrical activity; however, higher levels of pretreatment gastric tachyarrhythmia may be related to posttreatment reports of chemotherapy-induced nausea.

The stomach's response to unappetizing food: cephalic-vagal effects on gastric myoelectric activity.

The aim of this investigation was to determine the effects of sham feeding food that was perceived as unappetizing on the cephalic-vagal reflex as measured by changes in gastric myoelectric activity. Thirty-eight healthy human participants experienced one of two conditions: (i) an appetizing sham feeding condition in which participants chewed and expectorated two cooked frankfurters, and (ii) an unappetizing sham-feeding condition in which participants chewed and expectorated two cold tofu frankfurters. All participants were asked to chew each mouth-full of food 6-7 times and to be very careful not to swallow any of the food. Electrogastrograms (EGGs) were recorded for 10 min prior to, during, and for 15 min after sham feeding. A questionnaire was given to each participant after the procedure as a manipulation check and to assess food palatability. Results from the questionnaire showed, as expected, that the cooked frankfurters were significantly more appetizing than the cold tofu frankfurters (P < 0.01). In the group sham fed appetizing food, 3 cycles per minute (cpm) power increased during sham feeding, but the change was not significant; however, 3 cpm power decreased in the group sham fed unappetizing food. This difference was significant (P < 0.05). In conclusion, we have demonstrated that the cephalic-vagal reflex, as measured by power in the 3 cpm frequency region of the EGG, is sensitive to the subjective palatability of the food.

A questionnaire for the assessment of the multiple dimensions of motion sickness.

BACKGROUND: A limited number of attempts have been made to develop a questionnaire that assesses the experience of motion sickness. Further, many available questionnaires quantify motion sickness as a unidimensional construct. METHOD: Exploratory and confirmatory factor analyses of motion sickness descriptors were used to derive and verify four dimensions of motion sickness, which were defined as gastrointestinal, central, peripheral, and sopite-related. These dimensions of motion sickness were then used to construct a motion sickness assessment questionnaire (MSAQ) that was administered to individuals who were exposed to a rotating optokinetic drum. RESULTS: Total scores from the MSAQ correlated strongly with overall scores from the Pensacola Diagnostic Index (r = 0.81, p < 0.001) and the Nausea Profile (r = 0.92, p < 0.001). CONCLUSIONS: The MSAQ is a valid instrument for the assessment of motion sickness. In addition, the MSAQ may be used to assess motion sickness as a multidimensional rather than unidimensional construct.

The effects of serotonin (5-HT3) receptor antagonists on gastric tachyarrhythmia and the symptoms of motion sickness.

BACKGROUND: The purpose of this study was to determine the effects of the serotonin (5-HT3) receptor-antagonist antiemetics ondansetron and granisetron on the development of gastric tachyarrhythmia, nausea, and other symptoms of motion sickness. METHODS: In a double-blind, counterbalanced, repeated measures design, 12 motion sickness susceptible college students participated in 3 sessions with an intersession interval of 1 wk. Participants received either 8 mg of ondansetron, 2 mg of granisetron, or placebo 1 h before exposure to a rotating optokinetic drum. Electrogastrograms (EGGs) were recorded during a 6-min baseline period and a subsequent 16-min drum rotation period. Subjective symptoms of motion sickness (SSMS) were obtained every 3 min during drum rotation. RESULTS: During drum rotation, gastric tachyarrhythmia increased significantly more during the placebo condition than during either of the serotonin (5-HT3) receptor antagonist conditions. However, maximum SSMS scores were not different among conditions. CONCLUSIONS: The serotonin (5-HT3) receptor antagonists inhibited the development of tachyarrhythmia, but did not prevent the development of nausea and other symptoms of motion sickness. The antiemetics ondansetron and granisetron may act as gastric anti-dysrhythmics, but their ability to arrest the development of gastric tachyarrhythmia was not sufficient for the prevention of nausea.

Nausea and vomiting remain a significant clinical problem: trends over time in controlling chemotherapy-induced nausea and vomiting in 1413 patients treated in community clinical practices.

Data from 1413 outpatients in community-based clinical practices were collected in order to characterize the use and effectiveness of 5-HT(3) receptor antagonists for control of chemotherapy-induced nausea and vomiting (NV). Patients were divided by treatment starting date into six cohorts for trend analysis. In addition, NV symptoms were compared in 252 patients treated prior to the commercial introduction of the 5-HT(3) receptor antagonist antiemetics, and an equal number of patients treated after their introduction. A comparison of cohorts revealed a significant (P = 0. 027) downward trend over time for the frequency of post-treatment vomiting episodes, but not for frequency of post-treatment nausea (P = 0.69). The average duration of nausea following treatment increased significantly over time (P = 0.003). Although the introduction of 5-HT(3) receptor antagonist antiemetics has apparently led to a significant reduction in the frequency of post-treatment vomiting, there has been an accompanying increase in the duration of post-treatment nausea.

Significance of autonomic nervous system activity in functional dyspepsia.

The purpose of this study was to examine if patients with functional dyspepsia could be separated into meaningful groups based on their autonomic function. Subjects were divided into two groups, and symptoms, gastric myoelectrical activity, gastric emptying, and psychological factors were compared. Group 1 had less autonomic variability but more cardiac reactivity than group 2. Symptom reports did not differ between groups. Group 1 had higher neuroticism scores than group 2, while group 2 showed greater tachyarrhythmia in response to drinking water than group 1. The relatively low autonomic variability in group 1 is consistent with higher sympathetic activity and may be associated with the group's greater neuroticism. The relative lack of cardiac reactivity in group 2 is consistent with lack of autonomic flexibility and may be related to the tachyarrhythmia observed in that group. The results of this study suggest that autonomic function may play a significant role in functional dyspepsia.

Slow deep breathing prevents the development of tachygastria and symptoms of motion sickness.

BACKGROUND: The purpose of this study was to see if slow deep breathing, a non-pharmacological procedure known to increase parasympathetic nervous system (PNS) activity, would prevent the development of gastric dysrhythmias and symptoms of motion sickness when subjects were exposed to a rotating optokinetic drum. METHODS: Participating in this study were 46 healthy males and females aged 17-26 who were pre-tested in the rotating drum and found to be susceptible to motion sickness. They were randomly placed into one of the following three conditions: Slow Deep Breathing (n = 18), Counting Breaths (subjects were asked to count their breaths and asked for the count every 3 min, n = 16), and Control (subjects breathed normally, n = 12). Electrogastrograms were recorded from all subjects during a 6-min baseline and a 16-min rotation period. Subjects were asked about their symptoms every 3 min. RESULTS: A significant difference in percent tachygastria from baseline to rotation was found between the three conditions. Percent tachygastria increased during rotation for the Counting Breaths group and the Control group, but remained the same as baseline for the Slow Deep Breathing group. The Slow Deep Breathing group (5.3) reported significantly fewer symptoms than the Counting Breaths group (9.0), but not the Control group (7.8). CONCLUSION: In conclusion, slow deep breathing in a situation previously demonstrated to provoke tachygastria prevented the development of gastric dysrhythmias and decreased symptoms of motion sickness.

Effects of gender of subjects and experimenter on susceptibility to motion sickness.

BACKGROUND: It has been reported that females are more susceptible to motion sickness than males, but these reports have failed to take into account the possible effects of the gender of the experimenter and the subjective nature of reports of symptoms of motion sickness. To deal with the first possible confound, we used male and female experimenters. To deal with the second issue, we recorded gastric myoelectric activity so as to be able to quantify gastric tachyarrhythmia, an objective measure that has been shown previously to correlate highly with severity of symptoms. METHOD: There were 34 male and 34 female participants were assigned to either a male or female experimenter. Symptoms of motion sickness were induced by placing participants in an optokinetic drum for an 8-min baseline period followed by a 16-min rotation period. Electrogastrograms (EGGs) were continuously recorded, and reports of symptoms were obtained from the participants every 3 min during rotation. RESULTS: Comparison of male and female subjects' symptom scores revealed that females had higher symptom scores than males; however, no significant main effects for gender of the subject or experimenter were found. However, on a post-session questionnaire, females reported experiencing significantly more GI symptoms than males. Gender comparisons of the change in gastric tachyarrhythmia power from baseline to rotation yielded no significant differences. CONCLUSIONS: Females report more overall symptoms of motion sickness and significantly more GI symptoms than males, but do not show greater increases in gastric tachyarrhythmia during exposure to a rotating drum.

The retention of adaptation to motion sickness eliciting stimulation.

PURPOSE: This study compared the retention of adaptation to motion sickness eliciting stimulation after 1 mo and 1 yr. METHOD: A total of 34 subjects who developed nausea to an optokinetic rotating drum in a preliminary session repeatedly viewed the same rotation with an interval of 48 h between sessions until they had no feelings of nausea. For each session, subjects' electrogastrograms (EGGs) at 4-9 cycles per minute (cpm) were also recorded as a physiological index of the severity of motion sickness. Subjects were re-exposed to the optokinetic drum either after 1 mo or 1 yr. RESULTS: The mean ratings of nausea for the subjects who were re-exposed to the optokinetic drum after 1 mo were 9.23 for the initial exposure and 0.94 for the re-exposure session. EGG indicators of motion sickness were 6.65 for the initial exposure and 1.03 for the re-exposure session. The mean ratings of nausea for the subjects who were re-exposed to the optokinetic drum after 1 yr were 8.94 for the initial exposure and 6.88 for the re-exposure session. EGG indicators of motion sickness were 5.97 for the initial exposure and 4.05 for the re-exposure session. CONCLUSION: These results indicated that adaptation to the motion sickness eliciting stimulation of optokinetic rotation is almost completely retained for 1 mo and partially retained for 1 yr.

Use of 5-HT3 receptor antagonists to prevent nausea and emesis caused by chemotherapy for patients with breast carcinoma in community practice settings.

BACKGROUND: Although 5-HT3 receptor antagonists are clinically more effective in controlling emesis, particularly that caused by high dose cisplatin, than previously available agents, they appear to be less effective against nausea. This report focuses on the effectiveness of these agents against nausea and emesis in patients receiving two moderately emetogenic combination chemotherapy regimens as treatment for breast carcinoma in community practice settings. METHODS: Six hundred ninety-two breast carcinoma patients (688 female, 4 male; mean age, 51 years) enrolled in a nonrandomized study completed the Morrow Assessment of Nausea and Emesis (MANE) following 4 consecutive chemotherapy treatments. The frequency, duration, and severity of postchemotherapy nausea (PN) and postchemotherapy emesis (PE) were compared by type of antiemetic (5-HT3 receptor antagonist vs. other) and chemotherapy regimen (cyclophosphamide and doxorubicin with or without 5-fluorouracil [CA/CAF] vs. cyclophosphamide, methrotrexate, and 5-fluorouracil [CMF]). RESULTS: Within each regimen, the mean duration of PN was significantly longer for patients who received a 5-HT3 receptor antagonist than for those who were not given an antiemetic of that type (CA: 40.3 hours vs. 29.6 hours, P < 0.05; CMF: 37.6 hours vs. 30.2 hours, P < 0.05). There were no significant differences in the frequency or severity of nausea or in the frequency, severity, or duration of emesis by type of antiemetic for patients receiving either regimen. CONCLUSIONS: The results of this observational study suggest that 5-HT3 receptor antagonists are no more effective than other commonly used medications in controlling postchemotherapy nausea and emesis in women with breast carcinoma who are treated with moderately emetogenic chemotherapy in community practice settings. In fact, they may be associated with significant prolongation of the course of postchemotherapy nausea.

Effect of autonomic nervous system manipulations on gastric myoelectrical activity and emotional responses in healthy human subjects.

OBJECTIVE: The aim of this study was to determine the gastric myoelectrical and emotional responses provoked by two psychophysiological stimuli known to cause in one case increased sympathetic nervous system activity and in the other increased parasympathetic nervous system activity. METHODS: Electrogastrograms (EGGs) were recorded, and interbeat intervals (IBIs) were obtained from electrocardiographic recordings from 20 subjects during baseline and in response to a shock avoidance task (shock stimulus) and forehead cooling (dive stimulus). After each experimental period, subjects reported their emotional experience by rating descriptors ranging from serenity to excitement. RESULTS: During the shock stimulus, IBIs decreased significantly (p < .05), gastric tachyarrhythmias increased (p < .05), and emotional arousal increased, as indexed by reports of increased interest, excitement, and activation. In contrast, during the dive stimulus, IBIs increased (p < .05), but there were no associated changes in gastric myoelectrical activity or emotional arousal. CONCLUSIONS: Acute stress can evoke arousal and dysrhythmic gastric myoelectrical activity, and these acute changes, which occur in healthy individuals, may provide insight into functional gastrointestinal disorders.

Absence of habituation to repeated exposures to a rotating optokinetic drum with brief intersession intervals.

The purpose of this study was to investigate whether participants would habituate to repeated exposures to a rotating drum with brief intersession intervals. Participants were 41 college students, divided into a High Susceptibility group and a Low Susceptibility group based on their subjective symptoms of motion sickness during the first exposure to the rotating drum. The study consisted of three 16-min. exposures to a rotating drum with intersession intervals of 30 min. Contrary to expectation, for the High Susceptibility group, the symptom score mean of the first session was significantly less than that of the second and third sessions; and the drum viewing time of the first session was longer than that of the second and third sessions. In the Low Susceptibility group, the symptom score and drum viewing time were not significantly different among the three sessions. In conclusion, participants did not habituate to three repeated exposures to a rotating drum with intersession intervals of 30 min. Instead, a sensitization response occurred for the participants high in susceptibility.

Optokinetic nystagmus correlates with severity of vection-induced motion sickness and gastric tachyarrhythmia.

PURPOSE: The present study investigated the relationship of the frequency of nystagmus to the severity of optokinetic rotation-induced motion sickness. METHODS AND RESULTS: Eighty-seven subjects viewed a vertically striped, rotating drum for 16 min. Subjects' electrooculograms, ratings of vection, and subjective symptoms of motion sickness (SSMS) were measured during the drum rotation period. Subjects' electrogastrograms (EGGs) were recorded throughout the baseline and drum rotation periods. The ratios of the spectral intensity of EGG 4-9 cycles per minute (cpm) between drum rotation and baseline periods were calculated. The results indicated that the frequency of nystagmus was positively correlated with the ratings of vection (r = 0.40, p < 0.0001), scores of SSMS (r = 0.61, p < 0.0001), and ratios of EGG 4-9 cpm spectral intensity between drum rotation and baseline periods (r = 0.54, p < 0.0001). CONCLUSION: These results demonstrated that more rapid eye movement indexed by higher frequency of optokinetic nystagmus are related to the development of symptoms of motion sickness and gastric tachyarrhythmia.

The effect of autonomic nervous system activity on gastric myoelectrical activity: does the spectral reserve hypothesis hold for the stomach?

Previous studies have associated changes in gastric myoelectrical activity during motion sickness, as indexed using the electrogastrogram (EGG), with changes in autonomic nervous system (ANS) activity. Subjects who did not report nausea in a rotating optokinetic drum were characterized by normal 3 cycles per minute (cpm) gastric myoelectrical activity, strong parasympathetic nervous system (PNS) activity, and low sympathetic nervous system (SNS) activity. The goals of this study were: (1) to determine whether tasks previously shown to alter ANS activity as indexed by changes in cardiac inter-beat intervals (IBIs) would result in systematic changes in gastric myoelectrical activity in accord with the findings from motion sickness studies; and (2) to determine whether the 'spectral reserve hypothesis' applies to gastric myoelectrical activity. EGGs and IBIs were collected from 24 healthy subjects during resting/baseline, reaction time/shock-avoidance (RT) and cold face stress (CF) tasks. Tachyarrhythmia was found to be significantly greater during the RT task than during the baseline and CF tasks. It was concluded that: (1) tasks that alter ANS activity do systematically alter gastric myoelectrical activity; and (2) gastric myoelectrical activity does not follow the cardiac model of health being associated with increased spectral complexity.