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Coming theses from other universities

  • Cognition Seen Through the Eyes of Hearing Aid Users : Working Memory Resource Allocation for Speech Perception and Recall Author: Andreea Micula Link: Publication date: 2021-12-22 07:30

    This thesis investigates how hearing aid users allocate working (WM) memory resources under various task demands when listening to and storing speech in memory for later recall. This was done by combining an auditory recall task, the Sentence-final Word Identification and Recall (SWIR) test, with pupillometry. Different pupillary responses were used to obtain insights into momentary WM resource allocation and overall WM resource allocation over time. The task demands were manipulated by varying hearing aid noise reduction settings, as well as by varying the task difficulty of the SWIR test and the task difficulty predictability.

    The findings from the first two studies showed that recall performance in competing speech was better, and baseline pupillary responses were higher when noise reduction was activated compared to when it was not. This indicates that attenuating background noise frees up WM resources to be used for storing speech in memory rather than speech processing. While unpredictable task difficulty elicited higher baseline pupillary responses than predictable task difficulty, it did not have any effect on recall performance. This finding suggests that task difficulty predictability does not affect WM resource allocation. Instead, unpredictable task difficulty may lead to increased alertness in anticipation of the end of the SWIR test list. The findings of the third study showed that increased transient task-evoked pupillary responses, which reflect the momentary intensity of attention during encoding, were associated with a higher likelihood of subsequent recall. Moreover, higher WM capacity was also linked to higher likelihood of subsequent recall, presumably due to the ability to allocate more attentional resources during encoding. Lastly, the findings from the fourth study indicated that the combination of the SWIR test and pupillometry is suitable for capturing WM resource allocation. Although arousal decreased over time, recall performance remained stable, suggesting that participants did not reach the point of disengagement.

    Overall, a novel learning from this thesis is that increased pupillary responses may be a marker of “successful effort” when additional WM resources are allocated to achieve a better recall performance in the SWIR test. Furthermore, this thesis gives insights into which factors affect WM resource allocation and how to reduce the amount of processing resources required to understand speech, which may contribute to optimizing auditory rehabilitation in the future.

  • The extent of gynaecological cancer : Evaluation, outcome and quality of life Author: Björg Jónsdottir Link: Publication date: 2021-12-21 12:11

    The overall aim of this thesis was to enhance treatment planning for gynaecological cancer patients and identify women that are more likely to have impaired quality of life (QoL) after treatment. 

    In a retrospective cohort study on ovarian cancer, the peritoneal cancer index (PCI) was examined in relation to incomplete cytoreductive surgeries (CRS) and surgical complications (n=167). The PCI was found to be an excellent predictor of incomplete CRS (AUC 0.94). Complete CRS was obtained for only 67.2% of the patients with a PCI score higher than 24, who also experienced an increased rate of complications (p = 0.008). In a prospective study, radiologic PCI assessed with integrated PET/MRI and DW-MRI was compared with the surgical PCI as the gold standard (n=34). The median total PCI for PET/MRI (21.5) was closer to the surgical PCI (24.5) (p = 0.6) than to DW-MRI (20.0, p = 0.007). PET/MRI was more accurate (p = 0.3) for evaluating patients at primary diagnosis and for evaluating high tumour burden in inoperable patients.

    In a nationwide study, endometrial cancer patients included in the Swedish Quality Registry for Gynaecologic Cancer 2017-2019 (n=1401) were analysed with the aim of describing methods of evaluating myometrial invasion (MI). The main methods for the MI assessment were transvaginal sonography (59%) and MRI (28%). The sensitivity of transvaginal sonography (65.6%) was lower than for the other methods.

    In a longitudinal questionnaire-study, QoL in women with advanced gynaecological cancer was compared to women with local disease (n=372). No difference in QoL was found at the one-year follow-up. With multiple regression analyses, previous psychiatric illness, high BMI and comorbidities were identified as risk factors for impaired QoL.

    In conclusion, the PCI is an excellent predictor of incomplete CRS, and PCI ≥24 is a possible cut-off. PET/MRI is superior to DW-MRI for estimating total PCI. The assessment of MI in endometrial cancer in Sweden is usually performed with transvaginal sonography, but the sensitivity is lower than for other methods. Women with advanced gynaecological cancer have equally good QoL one year after diagnosis as women with limited disease, and psychiatric illness, high BMI, and comorbidities are risk factors for impaired mental health.

  • Surgical treatment of spinal metastasis Author: Christian Carrwik Link: Publication date: 2021-12-21 08:37

    The aim of this thesis was to study surgical treatment of spinal metastasis from several points of view, with a focus on predictive tools and survival after surgery. 

    Study I includes 315 patients treated surgically at Uppsala University Hospital 2006-2012 due to spinal metastatic disease. Based on the data known at the time of surgery, predictive scores were calculated using four different scoring systems (Tokuhashi, revised Tokuhashi, Tomita and modified Bauer scores). The predictions were then compared with true survival data. All of the scores had a statistically significant correlation to survival but all of them tended to underestimate rather than overestimate survival. 

    Study II focused on patients with an unknown primary tumour (UPT). We reviewed 393 cases treated at Uppsala University Hospital, where 122 (31%) had an unknown primary tumour at the time of surgery. A survival analysis showed that the patients with an UPT had a longer estimated survival compared to the group with a known primary tumour (KPT). The estimated median survival time in the UPT group was 15.6 months, compared to 7.4 months in the KPT group. The mean estimated survival time was 48.1 months in the UPT group and 21.6 months in the KPT group. The difference was statistically significant (p=0.001).

    Study III is a retrospective multi-registry study linking the Swedish spine surgery database Swespine with the Swedish Cause of Death (CoD) Register. The analysis included 1820 patients who underwent surgery due to spinal metastatic disease at 19 hospitals in Sweden 2006-2016. The study showed that both the mean and the median estimated survival time after surgery are well above the recommended three months threshold for surgery, suggesting that surgical treatment could be indicated in even more cases. 

    In study IV, prognostic tools were revisited with a validation study of PathFx 3.0, an online open-source tool to estimate survival for patients with skeletal metastases. A cohort of 668 patients treated at Uppsala University Hospital and Karolinska University Hospital were included in the study and the results indicate that PathFx 3.0 could predict survival after treatment with good reliability, especially for patients with long expected survival. As PathFx can be updated to reflect advancements in oncological treatment, this type of tool is probably more useful than the rigid point-based scoring systems evaluated in study I.