Quantitative measures of discrimination with application to appointment processes.

Bias and discrimination in appointment processes such as hiring decisions (and analogous selection procedures for performance evaluations, promotions, scholarships, and awards), are quantified statistically via the binomial distribution. These statistical measures are described and an easily used webapp for calculating them is provided. The measures considered include the likelihood that a given number of appointments arose from a fair process and the likelihood that an existing process would give rise to a fair outcome if it were repeated. These methods are illustrated by applying them to sex (including gender) discrimination and racial discrimination in senior appointments in the Australian university sector; both conscious and unconscious biases are included. Significant sex discrimination is found to have existed in the appointments of university chief executives (Vice Chancellors) who were in office in 2018, but with a moderate chance that current processes will yield fair outcomes in the future. However, there is no evidence of strong sex discrimination in the country's eight main research universities for senior appointments (i.e., Faculty Deans and members of their governing Boards or Senates) for those in office as of 2021. However, at the same dates, extreme racial discrimination was implicit in the selection procedures for both Vice Chancellors and senior appointments in all these universities. The University of Sydney's senior appointments were found to have had the most racially biased outcomes among the country's eight main research universities. Significantly, there is negligible statistical likelihood of achieving racially unbiased outcomes in the future in any of the contexts considered, unless the selection procedures are significantly modified.

Statistical and agent-based modelling of the transmissibility of different SARS-CoV-2 variants in England and impact of different interventions.

The English SARS-CoV-2 epidemic has been affected by the emergence of new viral variants such as B.1.177, Alpha and Delta, and changing restrictions. We used statistical models and the agent-based model Covasim, in June 2021, to estimate B.1.177 to be 20% more transmissible than the wild type, Alpha to be 50-80% more transmissible than B.1.177 and Delta to be 65-90% more transmissible than Alpha. Using these estimates in Covasim (calibrated 1 September 2020 to 20 June 2021), in June 2021, we found that due to the high transmissibility of Delta, resurgence in infections driven by the Delta variant would not be prevented, but would be strongly reduced by delaying the relaxation of restrictions by one month and with continued vaccination. This article is part of the theme issue 'Technical challenges of modelling real-life epidemics and examples of overcoming these'.

Changing demographics and immunity to vaccine preventable diseases in people with HIV in Ireland.

BACKGROUND: HIV infection is associated with an increased risk of morbidity and mortality from vaccine preventable infections. This research describes, in the context of changing patient demographics, the seroprevalence of vaccine preventable viral infections among attendees of the largest centre for HIV positive patients in Ireland. METHODS: Baseline serum IgG results for measles, mumps, rubella, varicella zoster virus (VZV) & hepatitis A, as well as hepatitis B sAg, cAb and sAb results, were retrieved for 2534 clinic attendees attending in 2018. Results were available for between 990 and 2363 attendees (39-93%), depending on the test, and were compared with 2013 clinic data. RESULTS: There was a 35% increase in attendees in 2018 when compared to 2013. The largest increase was in attendees of South American origin. In 2018, males accounted for 73% of the entire cohort and the HIV acquisition risk for 48% of attendees was MSM. 47% of attendees were originally from Ireland. Among those tested, 33% were susceptible to at least one component of the MMR vaccine. 5% were VZV non-immune (significantly associated with younger age and the acquisition risk status of injection drug use). 21% were hepatitis A non-immune (significantly associated with younger age and being of European or South American origin). 32% were hepatitis B cAb seropositive (significantly associated with older age, injection drug use status and being originally from Africa). 3% demonstrated hepatitis B sAg positivity. 64% had hepatitis B sAb ≥ 10mIU. CONCLUSION: In a cohort of attendees to an HIV clinic in a large urban setting, the susceptibility to several common vaccine preventable viral infections, in particular MMR and hepatitis A and B, was high. These results highlight the importance of proactive screening and immunisation to help protect this high risk patient group against vaccine preventable diseases.

Modelling the impact of reopening schools in the UK in early 2021 in the presence of the alpha variant and with roll-out of vaccination against SARS-CoV-2.

Following the resurgence of the COVID-19 epidemic in the UK in late 2020 and the emergence of the alpha (also known as B117) variant of the SARS-CoV-2 virus, a third national lockdown was imposed from January 4, 2021. Following the decline of COVID-19 cases over the remainder of January 2021, the question of when and how to reopen schools became an increasingly pressing one in early 2021. This study models the impact of a partial national lockdown with social distancing measures enacted in communities and workplaces under different strategies of reopening schools from March 8, 2021 and compares it to the impact of continual full national lockdown remaining until April 19, 2021. We used our previously published agent-based model, Covasim, to model the emergence of the alpha variant over September 1, 2020 to January 31, 2021 in presence of Test, Trace and Isolate (TTI) strategies. We extended the model to incorporate the impacts of the roll-out of a two-dose vaccine against COVID-19, with 200,000 daily vaccine doses prioritised by age starting with people 75 years or older, assuming vaccination offers a 95% reduction in disease acquisition risk and a 30% reduction in transmission risk. We used the model, calibrated until January 25, 2021, to simulate the impact of a full national lockdown (FNL) with schools closed until April 19, 2021 versus four different partial national lockdown (PNL) scenarios with different elements of schooling open: 1) staggered PNL with primary schools and exam-entry years (years 11 and 13) returning on March 8, 2021 and the rest of the schools years on March 15, 2020; 2) full-return PNL with both primary and secondary schools returning on March 8, 2021; 3) primary-only PNL with primary schools and exam critical years (years 11 and 13) going back only on March 8, 2021 with the rest of the secondary schools back on April 19, 2021 and 4) part-rota PNL with both primary and secondary schools returning on March 8, 2021 with primary schools remaining open continuously but secondary schools on a two-weekly rota-system with years alternating between a fortnight of face-to-face and remote learning until April 19, 2021. Across all scenarios, we projected the number of new daily cases, cumulative deaths and effective reproduction number R until April 30, 2021. Our calibration across different scenarios is consistent with alpha variant being around 60% more transmissible than the wild type. We find that strict social distancing measures, i.e. national lockdowns, were essential in containing the spread of the virus and controlling hospitalisations and deaths during January and February 2021. We estimated that a national lockdown over January and February 2021 would reduce the number of cases by early March to levels similar to those seen in October 2020, with R also falling and remaining below 1 over this period. We estimated that infections would start to increase when schools reopened, but found that if other parts of society remain closed, this resurgence would not be sufficient to bring R above 1. Reopening primary schools and exam critical years only or having primary schools open continuously with secondary schools on rotas was estimated to lead to lower increases in cases and R than if all schools opened. Without an increase in vaccination above the levels seen in January and February, we estimate that R could have increased above 1 following the reopening of society, simulated here from April 19, 2021. Our findings suggest that stringent measures were integral in mitigating the increase in cases and bringing R below 1 over January and February 2021. We found that it was plausible that a PNL with schools partially open from March 8, 2021 and the rest of the society remaining closed until April 19, 2021 would keep R below 1, with some increase evident in infections compared to continual FNL until April 19, 2021. Reopening society in mid-April, without an increase in vaccination levels, could push R above 1 and induce a surge in infections, but the effect of vaccination may be able to control this in future depending on the transmission blocking properties of the vaccines.

A Comparison of the Performance of SARS-CoV-2 Antibody Assays in Healthcare Workers with COVID-19.

Aims Since its emergence, significant interest surrounds the use of SARS-CoV-2 serological tests as an alternative or as an adjunct to molecular testing. However, given the speed of this pandemic, paralleled with the pressure to develop and provide serological tests in an expediated manner, not every assay has undergone the rigorous evaluation that is usually associated with medical diagnostic assays. We aimed to examine the performance of several commercially available SARS-CoV-2 IgG antibody assays among participants with confirmed COVID-19 disease and negative controls. Methods Serum taken between day 17 and day 40 post onset of symptoms from 41 healthcare workers with RT-PCR confirmed COVID-19 disease, and pre-pandemic serum from 20 negative controls, were tested for the presence of SARS-CoV-2 IgG using 7 different assays including point-of-care (POC) and laboratory-based assays. Results Assay performance varied. The lab-based Abbott diagnostics SARS-CoV-2 IgG assay proved to be the assay with the best positive and negative predictive value, and overall accuracy. The POC Nal von Minden GmbH and Biozek assays also performed well. Conclusion Our research demonstrates the variations in performance of several commercially available SARS-CoV-2 antibody assays. These findings identify the limitations of some serological tests for SARS-CoV-2. This information will help inform test selection and may have particular relevance to providers operating beyond accredited laboratories.

Modelling the potential impact of mask use in schools and society on COVID-19 control in the UK.

As the UK reopened after the first wave of the COVID-19 epidemic, crucial questions emerged around the role for ongoing interventions, including test-trace-isolate (TTI) strategies and mandatory masks. Here we assess the importance of masks in secondary schools by evaluating their impact over September 1-October 23, 2020. We show that, assuming TTI levels from August 2020 and no fundamental changes in the virus's transmissibility, adoption of masks in secondary schools would have reduced the predicted size of a second wave, but preventing it would have required 68% or 46% of those with symptoms to seek testing (assuming masks' effective coverage 15% or 30% respectively). With masks in community settings but not secondary schools, the required testing rates increase to 76% and 57%.

Population-based study on the prevalence and clinical profile of adults with cerebral palsy in Northern Ireland.

OBJECTIVES: This study aimed to report the prevalence and clinical characteristics of adults with cerebral palsy (CP) in a geographically defined region of the UK. DESIGN AND SETTING: Cross-sectional study using the Northern Ireland Cerebral Palsy Register (NICPR). PARTICIPANTS: All validated cases known to the NICPR, born 1981-2001 and alive and resident in Northern Ireland at age 19 years were included. RESULTS: The study included 1218 persons with CP aged 19-39 years, 46 of whom died in adulthood. The prevalence of CP was 2.38 per 1000. The majority of cases had spastic CP (n=1132/1218, 93%) and could walk (n=949/1218, 78%). Those that died in adulthood typically had bilateral spastic CP (n=39/46) and used a wheelchair (n=40/46). CONCLUSION: The prevalence of CP in adults is similar to other common neurological conditions such as multiple sclerosis and Parkinson's disease. The needs of adults with CP vary widely with almost half having two or more associated impairments that may require multiprofessional and multiagency coordination. Results from this study can be used to inform transformation of health and care services for adults with CP.

Transition from child to adult health services for young people with cerebral palsy in Ireland: a mixed-methods study protocol.

INTRODUCTION: The transition from child to adult health services is a challenging and complex process for young people with cerebral palsy (CP). Poorly managed transition is associated with deterioration in health, increased hospitalisations and reduced quality of life. While international research identifies key practices that can improve the experience and outcomes of transition, there is a paucity of data in the Irish context. This research study aims to gain an insight into the experience of transition for young people with CP in Ireland. METHODS AND ANALYSIS: A convergent parallel mixed-methods design will be used to collect, analyse and interpret quantitative and qualitative data. Participants will be young people aged 16-22 years with CP, their parent(s)/carer(s) and service providers. Quantitative and qualitative data will be collected through questionnaires and interviews, respectively. Quantitative data will be reported using descriptive statistics. Where sufficient data are collected, we will examine associations between the experience of transition practices and sociodemographic and CP-related factors, respectively, using appropriate regression models. Associations between service provider characteristics and provision of key transition practices may also be explored using appropriate regression models. Qualitative data will be analysed using the Framework Method. A coding matrix based on key transitional practices identified from the literature will be used to identify convergence and divergence across study components at the integration stage. ETHICS AND DISSEMINATION: The study has been approved by the RCSI University of Medicine and Health Sciences Research Ethics Committee (REC201911010). Results will be presented to non-academic stakeholders through a variety of knowledge translation activities. Results will be published in open access, peer-reviewed journals and presented at national and international scientific conferences.

The optic nerve lamina region is a neural progenitor cell niche.

Retinal ganglion cell axons forming the optic nerve (ON) emerge unmyelinated from the eye and become myelinated after passage through the optic nerve lamina region (ONLR), a transitional area containing a vascular plexus. The ONLR has a number of unusual characteristics: it inhibits intraocular myelination, enables postnatal ON myelination of growing axons, modulates the fluid pressure differences between eye and brain, and is the primary lesion site in the age-related disease open angle glaucoma (OAG). We demonstrate that the human and rodent ONLR possesses a mitotically active, age-depletable neural progenitor cell (NPC) niche, with unique characteristics and culture requirements. These NPCs generate both forms of macroglia: astrocytes and oligodendrocytes, and can form neurospheres in culture. Using reporter mice with SOX2-driven, inducible gene expression, we show that ONLR-NPCs generate macroglial cells for the anterior ON. Early ONLR-NPC loss results in regional dysfunction and hypomyelination. In adulthood, ONLR-NPCs may enable glial replacement and remyelination. ONLR-NPC depletion may help explain why ON diseases such as OAG progress in severity during aging.

Management of anal intraepithelial neoplasia and anal squamous cell carcinoma at a tertiary referral centre with a dedicated infectious diseases unit: an 18-year review.

INTRODUCTION: Anal squamous cell carcinoma (ASCC) is a rare malignancy with rising incidence rates. Risk factors include human immunodeficiency virus (HIV) infection, high-risk sexual activity and HPV-related genitourinary dysplasia/neoplasia. There is an overlap between high-risk patients and those attending HIV Medicine/Sexual Health (HMSH) services. We hypothesised that HMSH involvement may facilitate earlier referral to colorectal surgeons, with better outcomes. METHODS: Retrospective review of all ASCC and anal intraepithelial neoplasia (AIN) treated at a tertiary-referral hospital with a dedicated HMSH clinic between 2000 and 2018. Comparative analysis was performed of demographics, management and outcomes between HMSH and non-HMSH patients. RESULTS: One hundred and nine patients had anal pathology, eighty-five with ASCC (78%) and twenty-four with AIN (22%). Seventy (64%) were male. Median (range) age at ASCC diagnosis was 51 years (26-88). Thirty-six percent of all patients attended HMSH services, 28% were HIV positive, and 41% of males were men-who-have-sex-with-men (MSM). Eighty-one ASCC patients (97.5%) were treated with curative intent. Sixty-seven (80%) had primary chemoradiation therapy. Fifteen (17.5%) had primary surgical excision. Twelve (14%) developed recurrent disease. Ultimately, seven required salvage APR. Overall 3-year survival (3YS) was 76%. HMSH patients were significantly younger at ASCC diagnosis (p < 0.001), with a higher prevalence of HIV, HPV and MSM. HMSH attenders also tended to be diagnosed at earlier stages, were less likely to develop recurrence and achieved better overall outcomes, with a superior overall 3YS than non-HMSH patients (92% vs 72%, p = 0.037). CONCLUSION: ASCC incidence is increasing worldwide. The HMSH cohort has emerged as a distinct subpopulation of younger, high-risk, male patients. Collaboration between HMSH and colorectal surgeons offers an opportunity for risk reduction strategies and earlier intervention.

CD8 encephalitis with CSF EBV viraemia and HIV drug resistance, a case series.

INTRODUCTION: CD8 encephalitis is a relatively recently described condition in the setting of HIV infection. It is becoming increasingly recognised in recent years though is still likely underdiagnosed. METHODS: We present three cases of encephalitis in HIV-positive black African females initially presenting with neurological pathology. Two cases concern recent presentations of patients attending HIV services at a large tertiary referral hospital and the third case involves a retrospective analysis of an archived case. RESULTS AND DISCUSSION: MRI brain demonstrated periventricular white matter changes in 2 cases and a cerebellar lesion in the third case. CSF examination revealed lymphocytosis and elevated protein levels. CSF HIV viral load analysis showed viral escape along with new antiretroviral drug resistance mutations. CSF flow cytometry studies demonstrated a reversed CD4:CD8 ratio with a high CD8+ cells percentage. All patients had EBV DNA detected in their CSF. Brain biopsy in two patients confirmed CD8 encephalitis and also revealed isolated cells demonstrating EBV positivity by in-situ hybridization using EBER (Epstein-Barr virus-encoded small RNAs). Treatment with steroids and ART optimisation led to significant clinical and radiological improvements in all cases. DISCUSSION: CD8 encephalitis should be considered as a cause of neurological symptoms and confusion in the HIV-positive patient, particularly if poor ART adherence or viral resistance are suspected. Brain biopsy should be considered in HIV-positive patients with encephalopathy of uncertain cause. Early treatment with high-dose corticosteroids when suspecting this diagnosis is essential for a favourable outcome. The prognosis is variable but can be favourable even following severe encephalopathy. The presence of new INSTI mutations in the CSF but absent peripherally in two INSTI-era patients is a novel finding for this case series in the context of CD8 encephalitis. The role played by EBV in this disease remains unclear and warrants further investigation.

Estimating utilities/disutilities for high-risk metastatic hormone-sensitive prostate cancer (mHSPC) and treatment-related adverse events.

PURPOSE: To capture UK societal health utility values for high-risk metastatic hormone-sensitive prostate cancer (mHSPC) and the disutility associated with treatment-related adverse events (AEs) to inform future cost-utility analyses. METHODS: A literature review, and patient and clinical expert interviews informed the development of health states characterising mHSPC symptoms and the impact of treatment-related AEs on health-related quality of life (HRQL). Three base health states were developed describing a typical patient with high-risk mHSPC: receiving androgen deprivation therapy (ADT) [Base State 1]; receiving docetaxel plus ADT [Base State 2]; completed docetaxel and still receiving ADT whose disease has not yet progressed [Base State 3]. Six additional health states described treatment-related AEs. The health states were validated with experts and piloted with general public participants. Health state utilities were obtained using the time trade-off (TTO) method with 200 members of the UK general population. A generalised estimating equation (GEE) model was used to estimate disutility weights. RESULTS: Mean TTO scores for Base State 1 to 3 were 0.71 (SD = 0.26), 0.64 (SD = 0.27), and 0.68 (SD = 0.26), respectively, indicating that receiving docetaxel plus ADT was most impactful on HRQL. The GEE model indicated when compared to Base State 2 that the nausea and vomiting AE had the most impact on HRQL (- 0.21), while alopecia was least burdensome (- 0.04). CONCLUSIONS: The study highlights the differences in utility between base health states and the significant impact of treatment-related AEs on the HRQL of patients with mHSPC. These findings underline the importance of accounting for impaired HRQL when assessing treatments for mHSPC.

Kinematic differences between neutral and flat feet with and without symptoms as measured by the Oxford foot model.

BACKGROUND: Flatfoot is a common presentation in children. It is usually asymptomatic, though a small number of children experience pain. Foot function during flatfoot walking is rarely considered, yet as an activity that places significant demands on the feet, this could explain the differences in terms of symptoms. RESEARCH QUESTION: This paper investigates walking patterns in neutral and flat feet, with and without symptoms, to determine which kinematic parameters are associated with symptomatic flat feet. METHODS: This is a retrospective study in which one hundred and six children between five and 18 years old were assessed by a physiotherapist for foot posture. Each foot was classified into one of four groups, giving 98 asymptomatic neutral, 47 asymptomatic mild flat, 29 asymptomatic flat, and 38 symptomatic flat feet with complete data for analysis. Using Plug-In-Gait and Oxford-Foot-Model markers, walking kinematics were measured, along with ground reaction forces. Median values of 14 lower limb joint angles were calculated at foot strike, midstance, and foot off. Each foot was treated as an independent sample. ANOVA and ANCOVA (with the speed-related variable relative stride length as the covariate) and post-hoc tests were used to assess whether angles differed between groups. RESULTS: The symptomatic flat feet showed significant differences from asymptomatic groups (most commonly the neutral feet) in terms of hip flexion, knee flexion and varus, hindfoot inversion-eversion, and forefoot abduction-adduction. Increased forefoot abduction occurred throughout stance phase in symptomatic flatfooted participants compared to all asymptomatic groups. SIGNIFICANCE: The results suggest that foot motion in the transverse plane is closely associated with the presence of symptoms in flat feet and that this is accompanied by changes in the kinematics of the ankle, knee, and hip.

Comparing embodiment experiences in expert meditators and non-meditators using the rubber hand illusion.

One assessment of embodiment is the rubber hand illusion (RHI), a visuo-tactile illusion in which individuals attribute a sense of ownership to a rubber hand and disownership to their real hand. Interestingly, interoception seems to influence RHI susceptibility. In this study, we administered the RHI and the Multidimensional Assessment of Interoceptive Awareness (MAIA) to examine embodiment experiences and interoceptive awareness in experienced meditators (n = 15) and non-meditators (n = 15). We found that meditators reported less intensity in rubber hand ownership, but there was no significant difference between groups with respect to disownership of their real hand or drift in finger proprioception. Moreover, we found, from our MAIA results, that disownership experiences were associated with a feeling of trusting one's body in non-meditators and with the ability to maintain attention to unpleasant bodily sensations in meditators. These results suggest a unique relationship between interoceptive awareness and embodiment related to meditation.

Ultrasound-guided adductor canal block: a cadaver study investigating the effect of a thigh tourniquet.

BACKGROUND: Placement of local anaesthetic within the adductor canal using ultrasonography is an alternative to femoral nerve blocks for postoperative pain relief after knee joint replacement surgery. However, the effect of an inflated thigh tourniquet on the distribution of local anaesthetic within the adductor canal is unknown. The aim of this cadaveric study was to compare the distribution of radio-opaque dye within the adductor canal in the presence or absence of an inflated thigh tourniquet. METHODS: Bilateral ultrasound-guided adductor canal blocks were performed on the thawed lower limbs of five fresh frozen human cadavers. The left and right lower cadaver limbs were randomised to receive or not receive a thigh tourniquet inflated to 300 mm Hg for 1 h. X-rays with iohexol radio-opaque dye were obtained in four views, and fiducial markers inserted as reference points. Virtual editing technology was used to recreate outlines representing the distribution of the radio-opaque dye and superimpose these on anatomical images. RESULTS: Radio-opaque dye was distributed on the medial aspect of the thighs with entire and well circumscribed margins. The majority of the radio-opaque dye was confined within the adductor canal. Superior-inferior dye distribution was 315 mm [95% confidence intervals (CI) 289-342] and 264 mm (95% CI 239-289) in the presence and absence of an inflated thigh tourniquet, respectively (diff 95% CI -80.46 to -22.22, P=0.0081). Image analysis using the recreated radio-opaque outlines suggested that the most proximal point of the radio-opaque dye was 100 mm (95% CI 82-117) or 117 mm (95% CI 62-171) below the inguinal ligament in the presence and absence of an inflated thigh tourniquet, respectively (diff 95% CI -38 to 72, P=0.456). CONCLUSIONS: Application and inflation of thigh tourniquets significantly increased the combined superior-inferior dye distribution within the adductor canal of cadaveric limbs. There was insufficient evidence to suggest significant proximal spread of 25 ml of local anaesthetic to involve the motor branches of the femoral nerve. In some patients, the local anaesthetic may reach the popliteal fossa in close approximation to the sciatic nerve.

Physiology-based ERPs in normal and abnormal states.

Evoked response potentials (ERPs) and other transients are modeled as impulse responses using physiology-based neural field theory (NFT) of the corticothalamic system of neural activity in the human brain that incorporates synaptic and dendritic dynamics, firing response, axonal propagation, and corticocortical and corticothalamic pathways. The properties of model-predicted ERPs are explored throughout the stability zone of the corticothalamic system, and predicted time series and wavelet spectra are also analyzed. This provides a unified treatment of predicted ERPs for both normal and abnormal states within the brain's stability zone, including likely parameters to represent abnormal states of reduced arousal.

Evolutionary algorithm optimization of biological learning parameters in a biomimetic neuroprosthesis.

Biomimetic simulation permits neuroscientists to better understand the complex neuronal dynamics of the brain. Embedding a biomimetic simulation in a closed-loop neuroprosthesis, which can read and write signals from the brain, will permit applications for amelioration of motor, psychiatric, and memory-related brain disorders. Biomimetic neuroprostheses require real-time adaptation to changes in the external environment, thus constituting an example of a dynamic data-driven application system. As model fidelity increases, so does the number of parameters and the complexity of finding appropriate parameter configurations. Instead of adapting synaptic weights via machine learning, we employed major biological learning methods: spike-timing dependent plasticity and reinforcement learning. We optimized the learning metaparameters using evolutionary algorithms, which were implemented in parallel and which used an island model approach to obtain sufficient speed. We employed these methods to train a cortical spiking model to utilize macaque brain activity, indicating a selected target, to drive a virtual musculoskeletal arm with realistic anatomical and biomechanical properties to reach to that target. The optimized system was able to reproduce macaque data from a comparable experimental motor task. These techniques can be used to efficiently tune the parameters of multiscale systems, linking realistic neuronal dynamics to behavior, and thus providing a useful tool for neuroscience and neuroprosthetics.

K-complexes, spindles, and ERPs as impulse responses: unification via neural field theory.

To interrelate K-complexes, spindles, evoked response potentials (ERPs), and spontaneous electroencephalography (EEG) using neural field theory (NFT), physiology-based NFT of the corticothalamic system is used to model cortical excitatory and inhibitory populations and thalamic relay and reticular nuclei. The impulse response function of the model is used to predict the responses to impulses, which are compared with transient waveforms in sleep studies. Fits to empirical data then allow underlying brain physiology to be inferred and compared with other waves. Spontaneous K-complexes, spindles, and other transient waveforms can be reproduced using NFT by treating them as evoked responses to impulsive stimuli with brain parameters appropriate to spontaneous EEG in sleep stage 2. Using this approach, spontaneous K-complexes and sleep spindles can be analyzed using the same single theory as previously been used to account for waking ERPs and other EEG phenomena. As a result, NFT can explain a wide variety of transient waveforms that have only been phenomenologically classified to date. This enables noninvasive fitting to be used to infer underlying physiological parameters. This physiology-based model reproduces the time series of different transient EEG waveforms; it has previously reproduced experimental EEG spectra, and waking ERPs, and many other observations, thereby unifying transient sleep waveforms with these phenomena.