The human vestibulo-ocular reflex (VOR) stabilizes gaze during head movement. The reflex is typically tested in a clinic or laboratory using passive rotations or artificial stimuli which measure the amount of damage the vestibular apparatus has suffered. However, during everyday activities the vestibular system is stimulated by active, self generated head movements. Head movements are often rapid and associated with the goal of achieving either gaze-fixation or re-fixation. Patients who complain of on-going symptoms will typically identify a particular position or movement that aggravates their symptoms in their everyday life. There is a need to identify objective parameters which correlate with the subjective complaints of patients whose symptoms persist after vestibular damage. In the first study, a gaze-refixation task, patients who complain of ongoing symptoms (poorly-compensated), during rapid head turns, after unilateral vestibular de-afferentation (uVD) were compared with those who did not have the same complaints (well-compensated) and normal subjects. Well- and poorly-compensated groups were sorted according to responses on a standardized questionnaire. All subjects were then located in a real-world, non-laboratory environment in which poorly-compensated subjects reported experiencing symptoms. Each subject’s head, eye and gaze displacement and velocity, head rotation frequency and blink or eye-lid closure were measured and analysed and compared between ipsi- and contra-lesional head rotations within and between subject groups. When subjects are able to generate their own active head rotations it has been suggested that a number of vestibular and extra-vestibular strategies might be employed to compensate for an impaired VOR. In subsequent studies, high resolution scleral search coils were used to identify the compensatory mechanisms used during active head rotations during a gaze-fixation task. A corrective saccade is typically observed during passive ipsilesional head rotations or “impulses” and might be potentiated during rapid, active or self-generated head rotations. The conditions which predict or contribute to the generation of the rapid, corrective eye movement were investigated. The results were compared with responses to passive head impulses of matched velocity and acceleration to determine if active head impulses could be used to identify a lesioned vestibular apparatus as is routinely clinically achieved with passive head impulses.

The human vestibulo-ocular reflex (VOR) stabilizes gaze during head movement. The reflex is typically tested in a clinic or laboratory using passive rotations or artificial stimuli which measure the amount of damage the vestibular apparatus has suffered. However, during everyday activities the vestibular system is stimulated by active, self generated head movements. Head movements are often rapid and associated with the goal of achieving either gaze-fixation or re-fixation. Patients who complain of on-going symptoms will typically identify a particular position or movement that aggravates their symptoms in their everyday life. There is a need to identify objective parameters which correlate with the subjective complaints of patients whose symptoms persist after vestibular damage. In the first study, a gaze-refixation task, patients who complain of ongoing symptoms (poorly-compensated), during rapid head turns, after unilateral vestibular de-afferentation (uVD) were compared with those who did not have the same complaints (well-compensated) and normal subjects. Well- and poorly-compensated groups were sorted according to responses on a standardized questionnaire. All subjects were then located in a real-world, non-laboratory environment in which poorly-compensated subjects reported experiencing symptoms. Each subject’s head, eye and gaze displacement and velocity, head rotation frequency and blink or eye-lid closure were measured and analysed and compared between ipsi- and contra-lesional head rotations within and between subject groups. When subjects are able to generate their own active head rotations it has been suggested that a number of vestibular and extra-vestibular strategies might be employed to compensate for an impaired VOR. In subsequent studies, high resolution scleral search coils were used to identify the compensatory mechanisms used during active head rotations during a gaze-fixation task. A corrective saccade is typically observed during passive ipsilesional head rotations or “impulses” and might be potentiated during rapid, active or self-generated head rotations. The conditions which predict or contribute to the generation of the rapid, corrective eye movement were investigated. The results were compared with responses to passive head impulses of matched velocity and acceleration to determine if active head impulses could be used to identify a lesioned vestibular apparatus as is routinely clinically achieved with passive head impulses.

Syfte och frågeställningar: Syftet med studien var att i) undersöka validiteten i befolkningens skattning av stillasittande (SED) respektive måttlig till kraftig fysisk aktivitet (MVPA) samt ii) beskriva eventuella skillnader mellan de som under-, över- respektive korrekt skattar sitt beteende. Följande frågeställningar utformades: 1) Förekommer diskrepans mellan deltagarnas subjektiva skattning av SED och MVPA jämfört med objektivt mätt fysisk aktivitet med accelerometer? 2) Skiljer sig de deltagare som under-, över- respektive korrekt skattar sitt beteende avseende kön, socioekonomisk status, BMI, konditionsvärde respektive självskattad hälsa? Metod: Studien använder data från the Swedish CArdioPulmonary bioImage Study (SCAPIS) pilotstudie där deltagarna besvarade ett frågeformulär samt bar en accelerometer i sju på varandra följande dagar (N = 652). I denna studie har fyra frågor använts ur SCAPIS deltagarenkät för att mäta deltagarnas subjektiva nivå av fysiska aktivitet. Diskrepans av SED respektive MVPA räknades fram som subjektivt skattad tid (enkätfrågorna) minus accelerometerns registrerade tid. Data beskrivs deskriptivt där populationen har kategoriserats i kvintiler utefter medianskillnaden mellan subjektivt skattad och objektivt mätt tid. Resultat: Medianvärdet för diskrepans av SED och MVPA var -180,2 min/dag (under-) respektive 18,6 min/dag (överskattning). Avseende diskrepans av SED föreligger signifikanta skillnader mellan kvintilerna för diskrepans av SED (p = 0,000), accelerometermätt tid i SED (p = 0,000) samt totalt antal registrerade minuter (p = 0,000). Inga signifikanta skillnader ses för kön (p = 0,744), socioekonomisk status (p = 0,986), BMI (p = 0,806), konditionsvärde (p = 0,727) eller självskattad hälsa (p = 0,385). Avseende diskrepans av MVPA föreligger signifikanta skillnader för diskrepans av MVPA (p = 0,000), accelerometer-mätt tid i både SED (p = 0,000) och MVPA (p = 0,000), antal registrerade minuter totalt (p = 0,001), socioekonomisk status (p = 0,001) samt självskattad hälsa (p = 0,009). Slutsats: Resultaten visar att det är en stor diskrepans mellan hur svenska medelålders män och kvinnor skattar SED respektive MVPA om man jämför med objektivt accelerometermätt tid. Det verkar dock inte finnas en viss kategori människor som under- eller överskattar SED mer än andra avseende de undersökta variablerna. Beträffande diskrepans av MVPA ses dock en tendens till ökad diskrepans för de som bor i socioekonomiska högstatusområden samt att de med god självskattad hälsa överskattar mer. Studiens resultat tyder även på att mer registreringstid med accelerometern medför ökad diskrepans av SED respektive MVPA. Mer forskning kring hur olika registreringstider påverkar utfallen är därför önskvärt. / Aim: The aim of this study was to i) examine the validity of the population estimates of sedentary behaviour (SED) and moderate to vigorous physical activity (MVPA) and ii) describe possible differences between groups that are under-, over- and correctly classifying their behaviour. The following questions were designed to answer the above aim: 1. Are there discrepancies between the participants self-reported SED and MVPA compared to objective measurement by accelerometer? 2. Do the participants who under-, over- and correctly classify their behaviour differ with respect to gender, socioeconomic status, fitness factor and self-rated health? Method: This study used data from the Swedish CArdioPulmonary bioImage pilot Study  (SCAPIS) where participants answered a questionnaire and wore an accelerometer for seven subsequent days (N = 652). Four questions were used to measure the participants’ physical activity level. Discrepancy of SED and MVPA was calculated as the difference between subjectively and objectively measured time. The data is descriptively presented where misclassification has been categorized into quintiles and estimated as median differences. Results: The median time for discrepancy of SED was for the whole population -180,2 min/day (under-) and for MVPA 18,6 min/dag (overestimation). Regarding discrepancy of SED, there were significant differences between quintiles for discrepancy of SED (p = 0,000), accelerometer-registered time in SED (p = 0,000) and total number of minutes registered (p = 0,000). No significant differences existed for gender (p = 0,744), socioeconomic status (p = 0,986), BMI (p = 0,806), fitness factor (p = 0,727) or self-rated health (p = 0,385). Regarding discrepancy of MVPA there were significant differences for discrepancy of MVPA (p = 0,000), accelerometer-registered time in SED (p = 0,000) and MVPA (p = 0,000) and total number of minutes registered (p = 0,001). Significance also existed for socioeconomic status (p = 0,001) and self-rated health (p = 0,009). Conclusion: The results show that the population in this study misclassify SED and MVPA and the differences between the quintiles are large. However, there seems to be no particular category of people who misclassify SED more than others in regards to the examined variables. Concerning discrepancy of MVPA, the results suggest that the discrepancy is greater for those with high socioeconomic status and that those with good self-rated health tend to overestimate more. The results also suggest that more time registered with accelerometer entails greater discrepancy. More research examining how different recording times affect outcomes is warranted. / <p>Kursen Projektarbete.</p><p>SCAPIS-projektet</p>

過往關於同志與身心健康的研究，多著重在此身分所帶來的負面影響。本研究採取不同的觀點，探索同志族群可能的韌性，檢驗主／客觀因應彈性（韌性的行為面）以及自我清晰程度（韌性的內在面）對於正負向心理適應的影響，以及性傾向在此關係中所扮演的調節效果。兩個研究皆以調查法收集不同性傾向者（主觀與客觀）的因應彈性、自我清晰程度、憂鬱程度（負向心理適應指標）與生活滿意度（正向心理適應指標）。研究一的壓力事件為參與者自陳其近期壓力事件，研究二的壓力事件則是研究者指定給予參與者去做評量。兩個研究皆發現，客觀因應彈性與憂鬱程度、生活滿意度無關；自我清晰程度越高者，其憂鬱程度越低，且性傾向未調節以上結果。不過，性傾向則調節了自我清晰程度與生活滿意度間的關係。同志族群的自我清晰程度越高、生活滿意度也會越高；異性戀者則無此關係。研究二則發現主觀因應彈性越高，其憂鬱程度越低、生活滿意度越高；然而主觀因應彈性與正、負向心理適應之間的關係，不會受到不同性傾向的調節。兩個研究結果幫助我們瞭解主觀因應彈性、自我清晰程度與心理適應之間的關係，以及此關係在不同性傾向者身上的面貌為何。 / Lesbians, gay men, and bisexual (LGB) individuals are often observed to have poorer psychological adjustments than heterosexual individuals. I adopted a different approach to explore potential strengths in being LGB individuals by testing the impacts of objective/subjective coping flexibility and self-concept clarity on positive and negative psychological adjustments, as well as how sexual orientation may moderate these relationships. Two survey studies in this thesis measured objective/subjective coping flexibility, self-concept clarity, depression and life satisfaction among people with different sexual orientations. To measure objective coping flexibility, participants reported their recent stress events in Study 1, and were given specific stress events to respond in Study 2. The two studies showed that objective coping flexibility was not associated with depression, nor with life satisfaction, whereas self-concept clarity was associated with depression negatively. Sexual orientation did not moderate the above findings. Sexual orientation did moderate the relationship between self-concept clarity and life satisfaction: Self-concept clarity was associated with life satisfaction positively among LGB individuals, but this association was not significant among heterosexual individuals. Study 2 showed that subjective coping flexibility was associated with depression negatively and with life satisfaction positively. Again, sexual orientation did not moderate the above finding. These findings further our understanding regarding objective and subjective coping flexibility, self-concept clarity and psychological adjustments among people with different sexual orientations.