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- Dahlman, Joakim, 1974-, et al.
(författare)
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Could sound be used as a strategy for reducing symptoms of perceived motion sickness?
- 2008
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Ingår i: Journal of NeuroEngineering and Rehabilitation. - : Springer Science and Business Media LLC. - 1743-0003. ; 5:35
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Tidskriftsartikel (refereegranskat)abstract
- Background: Working while exposed to motions, physically and psychologically affects a person. Traditionally, motion sickness symptom reduction has implied use of medication, which can lead to detrimental effects on performance. Non-pharmaceutical strategies, in turn, often require cognitive and perceptual attention. Hence, for people working in high demand environments where it is impossible to reallocate focus of attention, other strategies are called upon. The aim of the study was to investigate possible impact of a mitigation strategy on perceived motion sickness and psychophysiological responses, based on an artificial sound horizon compared with a non-positioned sound source.Method: Twenty-three healthy subjects were seated on a motion platform in an artificial sound horizon or in non-positioned sound, in random order with one week interval between the trials. Perceived motion sickness (Mal), maximum duration of exposure (ST), skin conductance, blood volume pulse, temperature, respiration rate, eye movements and heart rate were measured continuously throughout the trials.Results: Mal scores increased over time in both sound conditions, but the artificial sound horizon, applied as a mitigation strategy for perceived motion sickness, showed no significant effect on Mal scores or ST. The number of fixations increased with time in the non-positioned sound condition. Moreover, fixation time was longer in the nonpositioned sound condition compared with sound horizon, indicating that the subjects used more time to fixate and, hence, assumingly made fewer saccades.Conclusion: A subliminally presented artificial sound horizon did not significantly affect perceived motion sickness, psychophysiological variables or the time the subjects endured the motion sickness triggering stimuli. The number of fixations and fixation times increased over time in the non-positioned sound condition.
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| 2. |
- Dahlman, Joakim, 1974-, et al.
(författare)
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Effects of Motion Sickness on Encoding and Retrieval
- 2010
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Tidskriftsartikel (refereegranskat)abstract
- Objective: In this study, possible effects of motion sickness on encoding and retrieval of words were investigated. Background: The impact of motion sickness on human performance has been studied with regards to psychomotor functions and over learned skills, as well as to novel situations requiring encoding and retrieval skills through the use of short term memory. In this study, possible effects of motion sickness on encoding and retrieval of words were investigated. Method: Forty healthy participants, half of them males, performed a continuous recognition task (CRT) during exposure to a motion sickness triggering optokinetic drum. The CRT was employed as a measurement of performance and consisted of encoding and retrieval of words. The task consisted of three consecutive phases 1) encoding of familiar words; 2) encoding and retrieval of words under the influence of motion sickness; 3) retrieval of words after exposure. Results: Data analysis revealed no significant differences in the ability to encode or retrieve words during motion sickness compared with a control condition. In addition, there were no significant correlations between the level of motion sickness and performance of the CRT. Conclusion: The results indicate that encoding and retrieval of words are not affected by moderate levels of motion sickness. Application: This research has implications for operational settings where professionals experience moderate levels of motion sickness.
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| 3. |
- Dahlman, Joakim, 1974-, et al.
(författare)
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Performance and Autonomic Responses during Motion Sickness
- 2009
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Ingår i: Human Factors. - : SAGE Publications. - 0018-7208 .- 1547-8181. ; 51:1, s. 56-66
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of the study was to investigate how motion sickness, triggered by an optokinetic drum, affects short term memory performance and to explore autonomic responses to perceived motion sickness. Background: Previous research has found motion sickness to decrease performance, but it is not known how short term memory in particular is affected. Method: Thirty-eight healthy participants performed a listening span test while seated in a rotating optokinetic drum. Measurements of motion sickness, performance, heart rate, skin conductance, blood volume pulse, and pupil size were performed simultaneously throughout the experiment. Results: A total of 16 participants terminated the trial due to severe nausea, while the other 22 endured the full 25 minutes. Perceived motion sickness increased over time in both groups, but less among those who endured the trial. Short term memory performance decreased towards the end for those who terminated, while it increased for the other group. Results from the measured autonomic responses were ambiguous. Conclusion: The present study concludes that performance, measured as short term memory, declines as perceived motion sickness progresses. Application: This research has potential implications for command and control personnel in risk of developing motion sickness.
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| 4. |
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| 5. |
- Sjörs, Anna, 1981-, et al.
(författare)
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Effects of motion sickness on encoding and retrieval performance and on psychophysiological responses
- 2010
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Tidskriftsartikel (refereegranskat)abstract
- Motion sickness has previously been found to deteriorate performance, e.g., regarding psychomotor functions and short term memory. Sustained ability to perform, despite motion sickness, is crucial in complex working environments. This study focuses on effects of motion sickness on encoding and retrieval of words through the use of long term memory. In addition, the temporal development of different psychophysiological responses and their relationship with perceived motion sickness were investigated. Forty healthy participants performed an encoding and retrieval task during exposure to an optokinetic drum. The results were compared with data from 20 controls that performed the task without motion sickness exposure. Measurements of heart rate, heart rate variability, skin conductance, blood volume pulse, respiration rate, and skin temperature were made throughout optokinetic drum exposure. Data analyses revealed no significant effects of moderate levels of motion sickness on the ability to encode or retrieve words. We found positive relationships between subjective motion sickness ratings and heart rate, blood volume pulse and skin temperature whereas respiration rate was negatively related to perceived motion sickness. The psychophysiological measurements did not show consistent patterns of sympathetic activation and parasympathetic withdrawal, as could be expected. Hence, they are not recommended as predictors of motion sickness.
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| 6. |
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| 7. |
- Donlau, Marie, et al.
(författare)
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Children and youth with myelomeningoceles independence in managing clean intermittent catheterization in familiar settings
- 2011
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Ingår i: ACTA PAEDIATRICA. - : Wiley-Blackwell. - 0803-5253 .- 1651-2227. ; 100:3, s. 429-438
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Tidskriftsartikel (refereegranskat)abstract
- Aim: To examine the ability of children and youth with myelomeningocele to independently manage clean intermittent catheterization. Methods: There were 50 participants with myelomeningocele (5-18 years); 13 of them had also participated in a previous hospital-based study. Their abilities and interest in completing the toilet activity were examined at home or in school using an interview and the Canadian Occupational Performance Measure (COPM). Actual performance was observed and rated. Background variables were collected from medical records and KatAD+E tests. Results: In total, 48% were observed to perform the toilet activity independently, in comparison with 74% who self-reported independence. Univariate analyses found KatAD+E could predict who was independent. COPM failed to do so. Ability to remain focused and ambulation were predictors of independence, but age, sex and IQ were not. Multivariable analysis found time to completion to be the strongest predictor of independence. Four children were independent in their familiar environment, but not in the hospital setting, and six of 13 children maintained focus only in their familiar environment. Conclusions: Interviews were not sufficiently accurate to assess independence in the toilet activity. Instead, observations including time to completion are recommended. The execution of the toilet activity is influenced by the environmental context.
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| 8. |
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| 9. |
- Forsman, Fredrik, et al.
(författare)
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Eye tracking during high speed naviation at sea : Field trial in search of navigational gaze behaviour
- 2012
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Ingår i: Journal of Transportation Technologies. - : Scientific Research Publishing. - 2160-0473 .- 2160-0481. ; 2, s. 277-283
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Professional high speed sea navigational procedures are based on turn points, courses, dangers and steering cues in the environment. Since navigational aids have become less expensive and due to the fact that electronic sea charts can be integrated with both radar and transponder information, it may be assumed that traditional navigation by using paper based charts and radar will play a less significant role in the future, especially among less experienced navigators. Possible navigational differences between experienced and non-experienced boat drivers is thus of interest with regards to their use of navigational aids. It may be assumed that less experienced navigators rely too much on the information given by the electronic sea chart, despite the fact that it is based on GPS information that can be questioned, especially in littoral waters close to land.Method: This eye tracking study investigates gaze behaviour from 16 experi- enced and novice boat drivers during high speed navigation at sea.Results: The results show that the novice drivers look at objects that are close to themselves, like instrumentation, while the experienced look more at objects far away from the boat. This is in accordance with previous research on car drivers. Further, novice boat drivers used the elec-tronic navigational aids to a larger extent than the experienced, especially during high speed conditions. The experienced drivers focused much of their attention on objects outside the boat.Conclusions: The findings verify that novice boat drivers tend to rely on electronic navigational aids. Experienced drivers presumably use the navigational aids to verify what they have observed in the surrounding environment and further use the paper based sea chart to a larger extent than the novice drivers.
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| 10. |
- Sjörs, Anna, 1981-
(författare)
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I feel terrible! Can you measure that? : Exploring psychophysiological stress responses and their interactions with performance, subjective reports and health status
- 2010
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Despite recent research advances, there are still several common medical conditions whose underlying mechanisms are poorly understood. In conditions with few or diffuse physical findings, it can be difficult to diagnose and determine the state of the condition and its effects on working ability or performance, and the health care practitioners have to rely on the patient’s self-reports. Identification of objective measurements that are sensitive enough to aid in diagnosis or determination of the state of these conditions would thus be valuable. Psychophysiological measurements are generally non-invasive and have the potential to serve as such diagnostic or prognostic tools. In this thesis, psychophysiological reactions to different stressors were recorded in two selected medical conditions; namely motion sickness and chronic trapezius myalgia (musculoskeletal pain). These subjective conditions are unpleasant, unwanted and apparently serve no survival purpose. It is therefore important to elucidate any physical findings associated with them to, eventually, find new means to prevent the development of these conditions or to ameliorate symptoms.The overall aim of the thesis was to explore the development of psychophysiological responses to stressors in relation to performance and subjective reports in healthy individuals and in women with chronic trapezius myalgia. More in detail, the purpose was to identify psychophysiological responses that could provide information about the mechanisms behind, or serve as candidates for characterization of motion sickness and chronic trapezius myalgia, respectively.Responses to motion sickness, triggered by optokinetic stimulation, were studied in healthy individuals, whereas responses to repetitive low-force work and psychosocial stress were studied in women with chronic trapezius myalgia and in pain-free controls. In both medical conditions, the psychophysiological responses were accompanied by subjective reports. The effects of motion sickness on two different aspects of memory performance were tested during exposure to optokinetic stimulation. In the studies of chronic trapezius myalgia, psychophysiological responses were also related to health status, i.e., being a patient or a pain-free control and measurements of pain intensity, psychological symptoms, sleep-related problems and quality of life.The psychophysiological responses to optokinetic stimulation were inconclusive. Moderate levels of motion sickness did not affect memory performance, whereas decreased short term memory performance was seen in subjects reporting high levels of motion sickness. The autonomic responses and stress hormone secretion in response to low-force repetitive work and psychosocial stress in the chronic trapezius myalgia group were similar to those of the pain-free controls. However, muscle activity in the trapezius muscle was generally higher in the chronic trapezius myalgia group. There were indications of negative psychological states being related to a slower response and lower circadian variations of stress hormone secretion.With the present methods, it was possible to measure general stress responses but none of the measurements showed sufficient specificity to serve as predictors or indicators of motion sickness and chronic musculoskeletal pain, respectively. Summarizing, I cannot objectively measure how you feel; I still have to rely on your description of your condition.
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