Investigating and managing neonatal seizures in the UK: an explanatory sequential mixed methods approach

Background Neonatal seizures are difficult to diagnose and, when they are, tradition dictates first line treatment is phenobarbital. There is little data on how consultants diagnose neonatal seizures, choose when to treat or how they choose aetiological investigations or drug treatments. The purpose of this study was to assess the variation across the UK in the management of neonatal seizures and explore paediatricians’ views on their diagnosis and treatment. Methods An explanatory sequential mixed methods approach was used (QUAN→QUAL) with equal waiting between stages. We collected quantitative data from neonatology staff and paediatric neurologists using a questionnaire sent to neonatal units and via emails from the British Paediatric Neurology Association. We asked for copies of neonatal unit guidelines on the management of seizures. The data from questionnaires was used to identify16 consultants using semi-structured interviews. Thematic analysis was used to interpret qualitative data, which was triangulated with quantitative questionnaire data. Results One hundred questionnaires were returned: 47.7% thought levetiracetam was as, or equally, effective as phenobarbital; 9.2% thought it was less effective. 79.6% of clinicians had seen no side effects in neonates with levetiracetam. 97.8% of unit guidelines recommended phenobarbital first line, with wide variation in subsequent drug choice, aetiological investigations, and advice on when to start treatment. Thematic analysis revealed three themes: ‘Managing uncertainty with neonatal seizures’, ‘Moving practice forward’ and ‘Multidisciplinary team working’. Consultants noted collecting evidence on anti-convulsant drugs in neonates is problematic, and recommended a number of solutions, including collaboration to reach consensus guidelines, to reduce diagnostic and management uncertainty. Conclusions There is wide variation in the management of neonatal seizures and clinicians face many uncertainties. Our data has helped reveal some of the reasons for current practice and decision making. Suggestions to improve certainty include: educational initiatives to improve the ability of neonatal staff to describe suspicious events, greater use of video, closer working between neonatologists and neurologists, further research, and a national discussion to reach a consensus on a standardised approach to managing neonatal epileptic seizures

Forecasting hospital staff availability during the COVID-19 epidemic

The COVID-19 pandemic poses two challenges to healthcare providers. Firstly, a high number of patients require hospital admission. Second, a high number of healthcare staff are either falling ill with the infection, or self-isolating. This poses significant problems for the staffing of busy hospital departments. We have created a simple model which allows users to stress test their rota. The model provides plots of staff availability over time using either a constant infection rate, or a changing infection rate fitted to population-based infection curves. It allows users to gauge the extent and timing of dips in staff availability. The basic constant infection rate model is available within an on-line web application (https://covid19.shef.ac.uk). As for any model, our work is imperfect. However, it allows a range of infection rates to be simulated quickly across different work patterns. We hope it will be useful to those planning staff deployment and will stimulate debate on the most effective patterns of work during the COVID-19 epidemic

Female sex mitigates motor and behavioural phenotypes in TDP-43Q331K knock-in mice

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are overlapping neurodegenerative disorders. ALS is more commonly seen in men than women and the same may be the case for FTD. Preclinical models demonstrating sex-specific vulnerability may help to understand female resistance to ALS-FTD and thereby identify routes to therapy. We previously characterised a TDP-43Q331K knock-in mouse, which demonstrated behavioural phenotypes reminiscent of ALS-FTD in males. Here we present our behavioural observations of female TDP-43Q331K mutants. Female TDP-43Q331K knock-in mice displayed increased weight relative to wild-type and increased food intake at 20 months of age, much later than previously observed in male mutants. Spontaneous digging behaviour was initially normal and only declined in mutants in the second year of life. Gait analysis using Catwalk (https://www.noldus.com/catwalk-xt) found significant deficits in the second year of life, while nocturnal running behaviour was attenuated from ~ 250 days of life. These results indicate that while female TDP-43Q331K knock-in mice do display progressive behavioural phenotypes, these are less severe than we previously noted in male mutants. Further studies of male and female TDP-43Q331K knock-in mice may help to unravel the mechanisms underlying sex-specific vulnerability in ALS-FTD

Extensive phenotypic characterisation of a human TDP-43^Q331K transgenic mouse model of amyotrophic lateral sclerosis (ALS)

The majority of preclinical studies in ALS have relied on transgenic models with overexpression of mutant human superoxide dismutase 1 (SOD1), widely regarded to have failed in terms of translation of therapeutic effects. However, there are still no widely accepted models of other genetic subtypes of ALS. The majority of patients show ubiquitinated cytoplasmic inclusions of TAR DNA binding protein of 43 kilodaltons (TDP-43) in spinal motor neurons at the end stage of disease and a small proportion have mutations in TARDBP, the gene encoding TDP-43. TDP-43 transgenic mouse models have been produced, but have not been widely adopted. Here, we characterised one of these models available from the Jackson Laboratory in detail. Compared to TDP-43WT mice, TDP-43Q331K mice had 43% less hindlimb muscle mass at 6 months and a 73% reduction in hindlimb compound muscle action potential at 8 months of age. Rotarod and gait analysis indicated motor system decline with elevated weight gain. At the molecular level, the lack of TDP-43 cellular pathology was confirmed with a surprising increase in nuclear TDP-43 in motor neurons. Power analysis indicated group sizes of 12–14 mice are needed to detect 10–20% changes in measured parameters with a power of 80%, providing valid readouts for preclinical testing. Overall, this model may represent a useful component of multi-model pre-clinical therapeutic studies for ALS

Combining electromyography and Raman spectroscopy: optical EMG

Introduction/Aims: Electromyography (EMG) remains a key component of the diagnostic work-up for suspected neuromuscular disease, but it does not provide insight into the molecular composition of muscle which can provide diagnostic information. Raman spectroscopy is an emerging neuromuscular biomarker capable of generating highly specific, molecular fingerprints of tissue. Here, we present “optical EMG,” a combination of EMG and Raman spectroscopy, achieved using a single needle. Methods: An optical EMG needle was created to collect electrophysiological and Raman spectroscopic data during a single insertion. We tested functionality with in vivo recordings in the SOD1G93A mouse model of amyotrophic lateral sclerosis (ALS), using both transgenic (n = 10) and non-transgenic (NTg, n = 7) mice. Under anesthesia, compound muscle action potentials (CMAPs), spontaneous EMG activity and Raman spectra were recorded from both gastrocnemius muscles with the optical EMG needle. Standard concentric EMG needle recordings were also undertaken. Electrophysiological data were analyzed with standard univariate statistics, Raman data with both univariate and multivariate analyses. Results: A significant difference in CMAP amplitude was observed between SOD1G93A and NTg mice with optical EMG and standard concentric needles (p =.015 and p =.011, respectively). Spontaneous EMG activity (positive sharp waves) was detected in transgenic SOD1G93A mice only. Raman spectra demonstrated peaks associated with key muscle components. Significant differences in molecular composition between SOD1G93A and NTg muscle were identified through the Raman spectra. Discussion: Optical EMG can provide standard electrophysiological data and molecular Raman data during a single needle insertion and represents a potential biomarker for neuromuscular disease

The GLP-1 receptor agonist, liraglutide, fails to slow disease progression in SOD1G93A and TDP-43Q331K transgenic mouse models of ALS

GLP-1 receptor agonists used for the treatment of diabetes, have shown some neuroprotective effects in cellular and animal models of Alzheimer’s disease (AD) and Parkinson’s disease (PD). There are currently few studies investigating GLP-1 receptor agonists in the treatment of ALS, where these neuroprotective effects may be beneficial. Here we investigate the effects of liraglutide, a GLP-1 receptor agonist, in two well characterised transgenic mouse models of ALS (SOD1G93A and TDP-43Q331K) to determine if liraglutide could be a potential treatment in ALS patients. Doses of liraglutide previously shown to have efficacy in AD and PD mouse models were used. Behavioural testing was carried out to ascertain the effect of liraglutide on disease progression. Immunohistochemical analysis of tissue was used to determine any neuroprotective effects on the CNS. We found that liraglutide dosed animals showed no significant differences in disease progression when compared to vehicle dosed animals in either the SOD1G93A or TDP-43Q331K mouse models of ALS. We also observed no changes in motor neuron counts or glial activation in lumbar spinal cords of liraglutide treated mice compared to vehicle dosed mice. Overall, we found no evidence to support clinical evaluation of liraglutide as a potential candidate for the treatment of ALS

Tensor electrical impedance myography identifies bulbardisease progression in amyotrophic lateral sclerosis

Objective Electrical impedance myography (EIM) is a promising biomarker for amyotrophic lateral sclerosis (ALS). A key issue is how best to utilise the complex high dimensional, multi-frequency data output by EIM to fully characterise the progression of disease. Methods Muscle volume conduction properties were obtained from EIM recordings of the tongue across three electrode configurations and 14 input frequencies (76 Hz–625 kHz). Analyses of individual frequencies, averaged EIM spectra and non-negative tensor factorisation were undertaken. Longitudinal data were collected from 28 patients and 17 healthy volunteers at 3-monthly intervals for a maximum of 9 months. EIM was evaluated against the Amyotrophic Lateral Sclerosis Functional Rating Scale-Revised (ALSFRS-R) bulbar sub-score, tongue strength and an overall bulbar disease burden score. Results Longitudinal changes to individual patient EIM spectra demonstrated complex shifts in the spectral shape. At a group level, a clear pattern emerged over time, characterised by an increase in centre frequency and general shift to the right of the spectral shape. Tensor factorisation reduced the spectral data from a total of 168 data points per participant per recording to a single value which captured the complexity of the longitudinal data and which we call tensor EIM (T-EIM). The absolute change in tensor EIM significantly increased within 3 months and continued to do so over the 9-month study duration. In a hypothetical clinical trial scenario tensor EIM required fewer participants (n = 64 at 50% treatment effect), than single frequency measures (n range 87–802) or ALSFRS-R bulbar subscore (n = 298). Conclusions Changes to tongue EIM spectra over time in ALS are complex. Tensor EIM captured and quantified disease progression and was more sensitive to changes than single frequency EIM measures and other biomarkers of bulbar disease. Significance Objective biomarkers for the assessment of bulbar disease in ALS are lacking. Tensor EIM enhances the biomarker potential of EIM data and can improve bulbar symptom monitoring in clinical trials

Label-free fibre optic Raman spectroscopy with bounded simplex-structured matrix factorization for the serial study of serum in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is an incurable neurodegenerative disease in urgent need of disease biomarkers for the assessment of promising therapeutic candidates in clinical trials. Raman spectroscopy is an attractive technique for identifying disease related molecular changes due to its simplicity. Here, we describe a fibre optic fluid cell for undertaking spontaneous Raman spectroscopy studies of human biofluids that is suitable for use away from a standard laboratory setting. Using this system, we examined serum obtained from patients with ALS at their first presentation to our centre (n = 66) and 4 months later (n = 27). We analysed Raman spectra using bounded simplex-structured matrix factorization (BSSMF), a generalisation of non-negative matrix factorisation which uses the distribution of the original data to limit the factorisation modes (spectral patterns). Biomarkers associated with ALS disease such as measures of symptom severity, respiratory function and inflammatory/immune pathways (C3/C-reactive protein) correlated with baseline Raman modes. Between visit spectral changes were highly significant (p = 0.0002) and were related to protein structure. Comparison of Raman data with established ALS biomarkers as a trial outcome measure demonstrated a reduction in required sample size with BSSMF Raman. Our portable, simple to use fibre optic system allied to BSSMF shows promise in the quantification of disease-related changes in ALS over short timescales