AB064. Two case reports & review of literature: perioperative surgical management of symptomatic large non-functioning pituitary masses in early pregnancy.

BACKGROUND: Pituitary masses during pregnancy pose many challenges, requiring inputs from multidisciplinary teams. Where surgery is required, such as in cases of impending pituitary apoplexy, timing must be carefully selected. Several case reports have suggested good outcome with surgery in later trimesters or postpartum. However, insufficient data exists on surgical strategies for such patients with severe visual symptoms in early pregnancy. We report two patients with pituitary masses requiring surgical excision. METHODS: Review of patients' notes and imaging, with literature review. RESULTS: A 35-year-old gravida 2 para 1 female at 9 weeks gestational age (GA) presented with chronic bitemporal hemianopia, with acute left eye blurring of vision, identified during a pre-employment screening test. Imaging revealed a 38 mm × 29 mm × 33 mm sellar mass with compression onto the optic chiasm. She had no significant hormonal imbalances other than hyperprolactinemia and newly diagnosed Hashimoto's thyroiditis. She underwent transsphenoidal resection, with histology showing pituitary adenoma with blood clots. Similarly, our second patient was a 37-year-old gravida 4 para 2 female at 12 weeks GA with worsening bitemporal hemianopia with a 25 mm × 21 mm × 18 mm sellar mass displacing and compressing the optic chiasm. After resection she had marked objective improvement in her vision, but developed diabetes insipidus, and final histology revealed pituicytoma. Preoperative considerations for timing of surgery include pituitary apoplexy or acutely worsening visual field deficit. The pituitary physiologically increases in size during pregnancy, which can compress the optic chiasm and worsen visual deficit. In the case of apoplexy, delayed identification can have devastating consequences. However, major surgery in the first trimester may increase spontaneous miscarriage. The effects of imaging investigations from radiation, or gadolinium contrast administration, are also uncertain. While surgical positioning remains unaffected, other intraoperative considerations include strictly avoiding hypotension and using pregnancy-safe agents. Postoperative considerations include correcting hormonal deficiencies of hypopituitarism, including acute central hypocortisolism, diabetes insipidus and interruption of gonadotrophin production which could negatively affect pregnancy. Fetal heart rate must also be assessed. CONCLUSIONS: Determining timing of surgery to ensure well-being of both mother and fetus involves a difficult balance of risks. In our two cases, a thorough discussion with multidisciplinary input was required to achieve good outcomes.

The application of eXplainable artificial intelligence in studying cognition: A scoping review.

The rapid advancement of artificial intelligence (AI) has sparked renewed discussions on its trustworthiness and the concept of eXplainable AI (XAI). Recent research in neuroscience has emphasized the relevance of XAI in studying cognition. This scoping review aims to identify and analyze various XAI methods used to study the mechanisms and features of cognitive function and dysfunction. In this study, the collected evidence is qualitatively assessed to develop an effective framework for approaching XAI in cognitive neuroscience. Based on the Joanna Briggs Institute and preferred reporting items for systematic reviews and meta-analyses extension for scoping review guidelines, we searched for peer-reviewed articles on MEDLINE, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and Google Scholar. Two reviewers performed data screening, extraction, and thematic analysis in parallel. Twelve eligible experimental studies published in the past decade were included. The results showed that the majority (75%) focused on normal cognitive functions such as perception, social cognition, language, executive function, and memory, while others (25%) examined impaired cognition. The predominant XAI methods employed were intrinsic XAI (58.3%), followed by attribution-based (41.7%) and example-based (8.3%) post hoc methods. Explainability was applied at a local (66.7%) or global (33.3%) scope. The findings, predominantly correlational, were anatomical (83.3%) or nonanatomical (16.7%). In conclusion, while these XAI techniques were lauded for their predictive power, robustness, testability, and plausibility, limitations included oversimplification, confounding factors, and inconsistencies. The reviewed studies showcased the potential of XAI models while acknowledging current challenges in causality and oversimplification, particularly emphasizing the need for reproducibility.

Application of a Standardized Treatment Paradigm as a Strategy to Achieve Optimal Onco-Functional Balance in Glioma Surgery.

BACKGROUND: Gliomas, characterized by their invasive persistence and tendency to affect critical brain regions, pose a challenge in surgical resection due to the risk of neurological deficits. This study focuses on a personalized approach to achieving an optimal onco-functional balance in glioma resections, emphasizing maximal tumor removal while preserving the quality of life. METHODS: A retrospective analysis of 57 awake surgical resections of gliomas at the National University Hospital, Singapore, was conducted. The inclusion criteria were based on diagnosis, functional boundaries determined by direct electrical stimulation, preoperative Karnofsky Performance Status score, and absence of multifocal disease on MRI. The treatment approach included comprehensive neuropsychological evaluation, determination of suitability for awake surgery, and standard asleep-awake-asleep anesthesia protocol. Tumor resection techniques and postoperative care were systematically followed. RESULTS: The study included 53 patients (55.5% male, average age 39 years), predominantly right-handed. Over half reported seizures as their chief complaint. Tumors were mostly low-grade gliomas. Positive mapping of the primary motor cortex was conducted in all cases, with awake surgery completed in 77.2% of cases. New neurological deficits were observed in 26.3% of patients at 1 month after operation; most showed significant improvement at 6 months. CONCLUSION: The standardized treatment paradigm effectively achieved an optimal onco-functional balance in glioma patients. While some patients experienced neurological deficits postoperatively, the majority recovered to their preoperative baseline within 3 months. The approach prioritizes patient empowerment and customized utilization of functional mapping techniques, considering the challenge of preserving diverse languages in a multilingual patient population.

Hyperbaric oxygen for the treatment of carbon monoxide-induced delayed neurological sequelae: a case report and review of the literature.

Introduction: Hyperbaric oxygen treatment (HBOT) remains a recognised treatment for acute carbon monoxide (CO) poisoning, but the utility of HBOT in treating CO-induced delayed neurological sequelae (DNS) is not yet established. Case description: A 26-year old woman presented with reduced consciousness secondary to CO exposure from burning charcoal. She underwent a single session of HBOT with US Navy Treatment Table 5 within six hours of presentation, with full neurological recovery. Eight weeks later, she represented with progressive, debilitating neurological symptoms mimicking Parkinsonism. Magnetic resonance imaging of her brain demonstrated changes consistent with hypoxic ischaemic encephalopathy. The patient underwent 20 sessions of HBOT at 203 kPa (2 atmospheres absolute) for 115 minutes, and received intravenous methylprednisolone 1 g per day for three days. The patient's neurological symptoms completely resolved, and she returned to full-time professional work with no further recurrence. Discussion: Delayed neurological sequelae is a well-described complication of CO poisoning. In this case, the patient's debilitating neurocognitive symptoms resolved following HBOT. Existing literature on treatment of CO-induced DNS with HBOT consists mainly of small-scale studies and case reports, many of which similarly suggest that HBOT is effective in treating this complication. However, a large, randomised trial is required to adequately determine the effectiveness of HBOT in the treatment of CO-induced DNS, and an optimal treatment protocol.

Endovascular coiling versus neurosurgical clipping in the management of aneurysmal subarachnoid haemorrhage in the elderly: a multicenter cohort study.

The comparability of endovascular coiling over neurosurgical clipping has not been firmly established in elderly patients with aneurysmal subarachnoid haemorrhage (aSAH). Data were obtained from all patients with aSAH aged ≥60 across three tertiary hospitals in Singapore from 2014 to 2019. Outcome measures included modified Rankin Scale (mRS) score at 3 and at 6 months, and in-hospital mortality. Of the 134 patients analyzed, 84 (62.7%) underwent coiling and 50 (37.3%) underwent clipping. The endovascular group showed a higher incidence of good mRS score 0-2 at 3 months (OR = 2.45 [95%CI:1.16-5.20];p = 0.018), and a lower incidence of in-hospital mortality (OR = 0.31 [95%CI:0.10-0.91];p = 0.026). There were no significant difference between the two treatment groups in terms of good mRS score at 6 months (OR = 1.98 [95%CI:0.97-4.04];p = 0.060). There were no significant differences in the incidence of complications, such as aneurysm rebleed, delayed hydrocephalus, delayed ischemic neurological deficit and venous thromboembolism between the two treatment groups. However, fewer patients in the coiling group developed large infarcts requiring decompressive craniectomy (OR = 0.32 [95%CI:0.12-0.90];p = 0.025). Age, admission WFNS score I-III, and coiling were independent predictors of good functional outcomes at 3 months. Only age and admission WFNS score I-III remained significant predictors of good functional outcomes at 6 months. Endovascular coiling, compared with neurosurgical clipping, is associated with significantly better short term outcomes in carefully selected elderly patients with aSAH. Maximal intervention is recommended for aSAH in the young elderly age group and those with favorable WFNS scores.

Outcomes after surgical revascularization for adult Moyamoya disease: A Southeast Asian tertiary centre experience.

There are numerous studies on the natural history and outcomes of adult Moyamoya disease (MMD) in the literature, but limited data from Southeast Asian cohorts. Hence, we aimed to retrospectively review the clinical characteristics and outcomes after surgical revascularization for adult MMD in our Southeast Asian cohort. Patients were included if they were above 18 years old at the first surgical revascularization for MMD, and underwent surgery between 2012 and 2022 at the National University Hospital, Singapore. The outcomes were transient ischemic attack (TIA), ischemic stroke, intracerebral hemorrhage, and all-cause mortality during the postoperative follow-up period. In total, 26 patients who underwent 27 revascularization procedures were included. Most patients were of Chinese ethnicity, and the mean (SD) age at the time of surgery was 47.7 (12.6) years. The commonest clinical presentation was intracerebral hemorrhage, followed by TIA and ischemic stroke. Direct revascularization with superficial temporal artery-middle cerebral artery (STA-MCA) bypass was the most common procedure (24/27 surgeries, 88.9 %). The mean (SD) follow-up duration was 4.2 (2.5) years, during which the overall incidence of postoperative TIA/stroke was 25.9 % (7/27 surgeries), with most cases occurring within 7 days postoperatively. There were no mortalities during the postoperative follow-up period. Risk factors for 30-day postoperative TIA/stroke included a higher number of TIAs/strokes preoperatively (p = 0.044) and indirect revascularization (p = 0.028). Diabetes mellitus demonstrated a trend towards an increased risk of 30-day postoperative TIA/stroke, but this was not statistically significant (p = 0.056). These high-risk patients may benefit from more aggressive perioperative antithrombotic and hydration regimens.

An encryption-decryption framework to validating single-particle imaging.

We propose an encryption-decryption framework for validating diffraction intensity volumes reconstructed using single-particle imaging (SPI) with X-ray free-electron lasers (XFELs) when the ground truth volume is absent. This conceptual framework exploits each reconstructed volumes' ability to decipher latent variables (e.g. orientations) of unseen sentinel diffraction patterns. Using this framework, we quantify novel measures of orientation disconcurrence, inconsistency, and disagreement between the decryptions by two independently reconstructed volumes. We also study how these measures can be used to define data sufficiency and its relation to spatial resolution, and the practical consequences of focusing XFEL pulses to smaller foci. This conceptual framework overcomes critical ambiguities in using Fourier Shell Correlation (FSC) as a validation measure for SPI. Finally, we show how this encryption-decryption framework naturally leads to an information-theoretic reformulation of the resolving power of XFEL-SPI, which we hope will lead to principled frameworks for experiment and instrument design.

Optimizing the onco-functional balance in supratentorial brain tumour surgery: A single institution's initial experience with intraoperative cortico-subcortical mapping and monitoring in Singapore.

Intraoperative cortical mapping provides functional information that permits the safe and maximal resection of supratentorial lesions infiltrating the so-called eloquent cortex or subcortical white matter tracts. Primary and secondary brain tumours located in eloquent cortex can render surgical treatment ineffective if it results in new or worsening neurology. A cohort of forty-six consecutive patients with supratentorial tumours of variable pathology involving eloquent cortical regions and aided with intraoperative neurophysiology were included for retrospective analysis at a single-centre tertiary institution. Intraoperative neurophysiological data has been related to immediate post-operative neurologic status as well as 3-month follow-up in patients that underwent awake or asleep surgical resection. Patients that experienced new or worsening neurologic symptoms post-operatively demonstrated a high incidence of recovery at 3-months. Those without new neurologic symptoms post-operatively demonstrated little to no worsening at 3-months. Our study explored the extent to which cortical mapping permitted safe surgical resection whilst preserving neurologic function. To the authors' knowledge this is the first documented case series in Singapore that has incorporated a systematic and individually tailored multimodal workflow to cortico-subcortical mapping and monitoring for the safe resection of infiltrative lesions of the supratentorial region.

Changing Demographic Profiles of Patients With Traumatic Brain Injury: An Aging Concern.

Background: Trauma continues to be a common cause of mortality in Singapore. By understanding the epidemiology of Traumatic Brain Injury (TBI), healthcare professionals can be better equipped to tackle the increasing socioeconomic burden of disease, adopting better strategies in healthcare planning. Methodology: A retrospective review of 367 patients admitted with TBI to a tertiary medical institution from January to December 2014 was performed, studying demographic profiles, injury details and outcomes of these patients. Data was retrieved from the National Trauma Registry and the institution's database. Results: Two hundred thirty-four of the 367 patients included in this study fell into two age groups--19 to 40 years and ≥65 years. 58% of the TBI population were aged >60. Predominant mechanism of injuries in these groups were road traffic accidents and unwitnessed falls respectively. 39% of the Elderly group were on antiplatelet/anticoagulant agents (p < 0.001). While aggressive surgical intervention was more common in younger patients (p < 0.001), the elderly group had significantly longer lengths of hospital stay (p < 0.001). Though Glasgow Outcome Scale (GOS) scores at discharge were not significantly different between the two groups, elderly patients showed greater percentages of post-injury improvement subsequently. Conclusion: The demographics of TBI patients appears to have shifted toward an older population as compared to a decade ago, with an increased incidence of falls, highlighting a huge healthcare concern. We hope that this study will drive further nationwide studies in future, looking at the incidence and prevalence of TBI, and with the focus on tackling preventable causes of TBI.

Minimal motor for powering particle motion from spin imbalance.

We introduce a minimalistic quantum motor for coupled energy and particle transport. The system is composed of two spins, each coupled to a different bath and to a particle which can move on a ring consisting of three sites. We show that the energy flowing from the baths to the system can be partially converted to perform work against an external driving, even in the presence of moderate dissipation. We also analytically demonstrate the necessity of coupling between the spins. We suggest an experimental realization of our model using trapped ions or quantum dots.

Converting heat into directed transport on a tilted lattice.

We present a self-contained engine, which is made of one or more two-level systems, each of which is coupled to a single bath, as well as to a common load composed of a particle on a tilted lattice. We show that an increase in time of energy and entropy in the system composed of the spins and the particle, due to the interaction with the bath, can set the particle into upward motion at an average constant speed, even when driven by a single spin connected to a single bath. When considering an ensemble of different spins, the velocity of the particle is larger when the tilt is on resonance with any of the spins' energy splitting. Interestingly, we find regimes where the spins' polarization enters periodic cycles with the oscillation period being determined by the tilt of the lattice.

Generation of single photons with highly tunable wave shape from a cold atomic ensemble.

The generation of ultra-narrowband, pure and storable single photons with widely tunable wave shape is an enabling step toward hybrid quantum networks requiring interconnection of remote disparate quantum systems. It allows interaction of quantum light with several material systems, including photonic quantum memories, single trapped ions and opto-mechanical systems. Previous approaches have offered a limited tuning range of the photon duration of at most one order of magnitude. Here we report on a heralded single photon source with controllable emission time based on a cold atomic ensemble, which can generate photons with temporal durations varying over three orders of magnitude up to 10 µs without a significant change of the readout efficiency. We prove the nonclassicality of the emitted photons, show that they are emitted in a pure state, and demonstrate that ultra-long photons with nonstandard wave shape can be generated, which are ideally suited for several quantum information tasks.

Penile cancer: a local case series and literature review.

INTRODUCTION: Penile cancer is an uncommon disease affecting only about one in 100,000 men worldwide in a year. The diagnosis of the condition is frequently delayed, and the disease and its treatment frequently result in significant morbidity in patients. METHODS: We herein describe seven cases of penile tumours: six cases of squamous cell carcinomas and one case of B-cell lymphoma that presented to our hospital's urology department between March 2011 and October 2012. We reviewed the literature to discuss the clinical presentation, natural history and current management of penile cancer. RESULTS: The patients were followed up for 1-24 months. They were managed according to their disease stage and lymph node status. Four out of seven patients showed disease progression during the follow-up period. CONCLUSION: The accurate staging of inguinal nodes in cases of low-risk disease is important to prescribe appropriate surgery for the inguinal nodes. Aggressive management of inguinal and pelvic lymph nodes remains the cornerstone in the treatment of high-risk disease cases.

Validity of the Personality Diagnostic Questionnaire-4 (PDQ-4+) among mentally ill prison inmates in Singapore.

We examined the validity of the Personality Diagnostic Questionnaire--4+ (PDQ-4+) as a screening instrument for personality disorders among mentally ill prison inmates in Singapore. A total of 313 prison inmates completed the PDQ-4+ and the Structured Clinical Interview for DSM-IV Axis II Disorders (SCID-II). The subjects were 303 (96.8%) males and 10 (3.2%) females with a mean (SD) age of 40.7 (8.8) years. Kappa agreement between PDQ-4+ and SCID-II for the presence at least one personality disorder was moderate with high sensitivity and low specificity. For specific personality disorders and clusters, we found that the PDQ-4+ diagnosed more subjects as having each of the personality disorders than SCID-II with high negative predictive values. The area under the curve indicated moderate discriminatory capabilities. Our results suggest that the PDQ-4+ could be used as a potential screening instrument for personality disorders in prison inmates.