Effects of the search technique on the measurement of the change in quality of randomized controlled trials over time in the field of brain injury

BACKGROUND: To determine if the search technique that is used to sample randomized controlled trial (RCT) manuscripts from a field of medical science can influence the measurement of the change in quality over time in that field. METHODS: RCT manuscripts in the field of brain injury were identified using two readily-available search techniques: (1) a PubMed MEDLINE search, and (2) the Cochrane Injuries Group (CIG) trials registry. Seven criteria of quality were assessed in each manuscript and related to the year-of-publication of the RCT manuscripts by regression analysis. RESULTS: No change in the frequency of reporting of any individual quality criterion was found in the sample of RCT manuscripts identified by the PubMed MEDLINE search. In the RCT manuscripts of the CIG trials registry, three of the seven criteria showed significant or near-significant increases over time. CONCLUSIONS: We demonstrated that measuring the change in quality over time of a sample of RCT manuscripts from the field of brain injury can be greatly affected by the search technique. This poorly recognized factor may make measurements of the change in RCT quality over time within a given field of medical science unreliable

Facial nerve stimulation as a future treatment for ischemic stroke

Stimulation of the autonomic parasympathetic fibers of the facial nerve system (hereafter simply "facial nerve") rapidly dilates the cerebral arteries and increases cerebral blood flow whether that stimulation is delivered at the facial nerve trunk or at distal points such as the sphenopalatine ganglion. Facial nerve stimulation thus could be used as an emergency treatment of conditions of brain ischemia such as ischemic stroke. A rich history of scientific research has examined this property of the facial nerve, and various means of activating the facial nerve can be employed including noninvasive means. Herein, we review the anatomical and physiological research behind facial nerve stimulation and the facial nerve stimulation devices that are in development for the treatment of ischemic stroke

Facial nerve stimulation in normal pigs and healthy human volunteers: transitional development of a medical device for the emergency treatment of ischemic stroke

Abstract Background Magnetic stimulation of the facial nerve has been tested in preclinical studies as a new, non-invasive emergency treatment of ischemic stroke that acts by increasing cerebral blood flow (CBF). The objective of the studies reported herein was to identify minimal stimulation parameters that increase CBF in large animals and then test those stimulation parameters in healthy volunteers for safety, tolerability, and effectiveness at increasing CBF. This translational research is necessary preparation for clinical studies in ischemic stroke patients. Methods Initial experiments in anesthetized Yorkshire pigs were undertaken in order to identify the lowest stimulus power and duration that increase CBF. A full 3 × 3 factorial design was used to evaluate magnetic stimulation of the facial nerve at various stimulation powers (1.3, 1.6, and 1.9 Tesla field strength at coil surface) and for various durations (2, 3.5, and 5 min). CBF was measured with contrast MRI perfusion imaging and the internal carotid arteries were assessed with MR angiography. Magnetic facial nerve stimulation with parameters identified in the pig study was then applied to 35 healthy volunteers. Safety was assessed with adverse event reports and by medical examination. Tolerability was defined as each volunteer’s ability to withstand at least 2 min of stimulation. Volunteers could determine the maximum power of stimulation they received during a ramp-up period. Results In pigs, unilateral facial nerve stimulation increased CBF by as much as 77% over pre-stimulation baseline when administered across a range of 1.3–1.9 Tesla power and for 2- to 5-min duration. No clear dose–response relationship could be observed across this range, but lower powers and durations than these were markedly less effective. The effect of a single stimulation lasted 90 min. A second stimulation delivered 100 min after the first stimulation sustained the increased CBF without evidence of tachyphylaxis. In human, bilateral facial nerve stimulation caused only non-serious adverse events that were limited to the 2-min stimulation period. Tolerability was greatly improved by gentle encouragement from the study staff, which enabled most volunteers to tolerate 1.6–1.8 Tesla of stimulation power. CBF measures taken approximately 10 min after stimulation demonstrated on average a 32 ± 6% increase in CBF, with ≥ 25% increases in CBF occurring in 10 of the 31 volunteers who had adequate CBF measurements. Conclusions The minimal effective stimulation parameters defined by increased CBF, as identified in the pig study, translated into safe, tolerable, and effective stimulation of healthy volunteers. These results support the future development and evaluation of non-invasive facial nerve stimulation for the emergency treatment of ischemic stroke. Trial Registration retrospectively registered with clinicaltrials.gov NRV_P1_01_15 on June 6, 201

Haptoglobin genotype and aneurysmal subarachnoid haemorrhage: individual patient data analysis

Objective:To perform an individual patient level data (IPLD) analysis and determine the relationship between haptoglobin (HP) genotype and outcomes after aneurysmal subarachnoid haemorrhage (aSAH).Methods:The primary outcome was favourable outcome on the modified Rankin Scale or Glasgow Outcome Score up to 12 months post-ictus. The secondary outcomes were occurrence of delayed ischemic neurological deficit, radiological infarction, angiographic vasospasm and transcranial Doppler evidence of vasospasm. World Federation of Neurological Surgeons scale, Fisher grade, age and aneurysmal treatment modality were covariates for both primary and secondary outcomes. As pre-planned, a two-stage IPLD analysis was conducted, followed by these sensitivity analyses: (1) unadjusted; (2) exclusion of unpublished studies; (3) all permutations of HP genotypes; (4) sliding dichotomy; (5) ordinal regression; (6) one-stage analysis; (7) exclusion of studies not in Hardy-Weinberg Equilibrium (HWE); (8) inclusion of studies without the essential covariates; (9) inclusion of additional covariates; (10) only including covariates significant in univariate analysis.Results:Eleven studies (five published, six unpublished), totalling 939 patients, were included. Overall the study population was in HWE. Follow-up times were 1, 3 and 6 months for 355, 516 and 438 patients. HP genotype was not associated with any primary or secondary outcome. No trends were observed. When taken through the same analysis higher age and WFNS were associated with an unfavourable outcome as expected.Conclusion:This comprehensive IPLD analysis, carefully controlling for covariates, refutes previous studies showing that HP1-1 associates with better outcome after aSAH