Leber hereditary optic neuropathy (LHON) is a genetic disorder primarily due to mutations of mitochondrial DNA (mtDNA). Environmental factors are thought to precipitate the visual failure and explain the marked incomplete penetrance of LHON, but previous small studies have failed to confirm this to be the case. LHON has no treatment, so identifying environmental triggers is the key to disease prevention, whilst potentially revealing new mechanisms amenable to therapeutic manipulation. To address this issue, we conducted a large, multicentre epidemiological study of 196 affected and 206 unaffected carriers from 125 LHON pedigrees known to harbour one of the three primary pathogenic mtDNA mutations: m.3460G>A, m.11778G>A and m.14484T>C. A comprehensive history of exposure to smoking, alcohol and other putative environmental insults was collected using a structured questionnaire. We identified a strong and consistent association between visual loss and smoking, independent of gender and alcohol intake, leading to a clinical penetrance of 93% in men who smoked. There was a trend towards increased visual failure with alcohol, but only with a heavy intake. Based on these findings, asymptomatic carriers of a LHON mtDNA mutation should be strongly advised not to smoke and to moderate their alcohol intake.

Objective To systematically review the latest evidence for patient safety education for physicians in training and medical students, updating, extending and improving on a previous systematic review on this topic. Design A systematic review. Data sources Embase, Ovid Medline and PsycINFO databases. Study selection Studies including an evaluation of patient safety training interventions delivered to trainees/residents and medical students published between January 2009 and May 2014. Data extraction The review was performed using a structured data capture tool. Thematic analysis also identified factors influencing successful implementation of interventions. Results We identified 26 studies reporting patient safety interventions: 11 involving students and 15 involving trainees/residents. Common educational content included a general overview of patient safety, root cause/systems-based analysis, communication and teamwork skills, and quality improvement principles and methodologies. The majority of courses were well received by learners, and improved patient safety knowledge, skills and attitudes. Moreover, some interventions were shown to result in positive behaviours, notably subsequent engagement in quality improvement projects. No studies demonstrated patient benefit. Availability of expert faculty, competing curricular/service demands and institutional culture were important factors affecting implementation. Conclusions There is an increasing trend for developing educational interventions in patient safety delivered to trainees/residents and medical students. However, significant methodological shortcomings remain and additional evidence of impact on patient outcomes is needed. While there is some evidence of enhanced efforts to promote sustainability of such interventions, further work is needed to encourage their wider adoption and spread.

Object: There is increasing evidence that simulation provides high-quality, time-effective training in an era of resident duty-hour restrictions. Simulation may also permit trainees to acquire key skills in a safe environment, important in a specialty such as neurosurgery, where technical error can result in devastating consequences. The authors systematically reviewed the application of simulation within neurosurgical training and explored the state of the art in simulation within this specialty. To their knowledge this is the first systematic review published on this topic to date. Methods: The authors searched the Ovid MEDLINE, Embase, and PsycINFO databases and identified 4101 articles; 195 abstracts were screened by 2 authors for inclusion. The authors reviewed data on study population, study design and setting, outcome measures, key findings, and limitations. Results: Twenty-eight articles formed the basis of this systematic review. Several different simulators are at the neurosurgeon's disposal, including those for ventriculostomy, neuroendoscopic procedures, and spinal surgery, with evidence for improved performance in a range of procedures. Feedback from participants has generally been favorable. However, study quality was found to be poor overall, with many studies hampered by nonrandomized design, presenting normal rather than abnormal anatomy, lack of control groups and long-term follow-up, poor study reporting, lack of evidence of improved simulator performance translating into clinical benefit, and poor reliability and validity evidence. The mean Medical Education Research Study Quality Instrument score of included studies was 9.21 ± 1.95 (± SD) out of a possible score of 18. Conclusions: The authors demonstrate qualitative and quantitative benefits of a range of neurosurgical simulators but find significant shortfalls in methodology and design. Future studies should seek to improve study design and reporting, and provide long-term follow-up data on simulated and ideally patient outcomes.

Purpose. Leber hereditary optic neuropathy (LHON) is an inherited mitochondrial optic neuropathy characterized by bilateral, severe loss of central vision. In this study, the first formal assessment was conducted of visual disability in affected and unaffected individuals from molecularly confirmed LHON pedigrees. methods. Four hundred two LHON carriers—196 affected and 206 unaffected—from 125 genealogically distinct pedigrees were prospectively interviewed using the well-validated visual function index (VF-14) questionnaire: m.3460G>A (n = 71), m.11778G>A (n = 270), and m.14484T>C (n = 61). results. The mean age of onset of visual loss was 27.9 years (SD, 14.9) and mean disease duration was 15.5 years (SD, 15.4), with 74.5% of the affected subjects being men. The mean VF-14 score was 25.1 (SD, 20.8) in the affected patients, compared with 97.3 (SD, 7.1) in the unaffected carriers. Within the affected group, VF-14 score did not worsen with increasing disease duration and individuals with the m.14484T>C mutation had higher VF-14 scores compared with those in the m.3460G>A and m.11778G>A groups. Reading small print and reading a newspaper or book were the two VF-14 items that presented the greatest difficulty. conclusions. LHON has a severe negative impact on quality of life and has the worst VF-14 score when compared with other previously studied ophthalmic disorders. However, affected LHON carriers can be reassured that their level of visual impairment is unlikely to progress with time. The VF-14 questionnaire will be a useful tool for assessing the natural history of LHON and measuring outcome in future treatment trials.

Measurement of intracranial pressure (ICP) and mean arterial pressure (MAP) is used to derive cerebral perfusion pressure (CPP) and to guide targeted therapy of acute brain injury (ABI) during neurointensive care. Here we provide a narrative review of the evidence for ICP monitoring, CPP estimation, and ICP/CPP-guided therapy after ABI. Despite its widespread use, there is currently no class I evidence that ICP/CPP-guided therapy for any cerebral pathology improves outcomes; indeed some evidence suggests that it makes no difference, and some that it may worsen outcomes. Similarly, no class I evidence can currently advise the ideal CPP for any form of ABI. 'Optimal' CPP is likely patient-, time-, and pathology-specific. Further, CPP estimation requires correct referencing (at the level of the foramen of Monro as opposed to the level of the heart) for MAP measurement to avoid CPP over-estimation and adverse patient outcomes. Evidence is emerging for the role of other monitors of cerebral well-being that enable the clinician to employ an individualized multimodality monitoring approach in patients with ABI, and these are briefly reviewed. While acknowledging difficulties in conducting robust prospective randomized studies in this area, such high-quality evidence for the utility of ICP/CPP-directed therapy in ABI is urgently required. So, too, is the wider adoption of multimodality neuromonitoring to guide optimal management of ICP and CPP, and a greater understanding of the underlying pathophysiology of the different forms of ABI and what exactly the different monitoring tools used actually represent.