ABSTRACT
OBJECTIVE: Spin is characterized as a misinterpretation of results that, whether deliberate or unintentional, culminates in misleading conclusions and steers readers toward an excessively optimistic perspective of the data. The primary objective of this systematic review was to estimate the prevalence and nature of spin within the traumatic brain injury (TBI) literature. Additionally, the identification of associated factors is intended to provide guidance for future research practices. METHODS: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) recommendations were followed. A search of the MEDLINE/PubMed database was conducted to identify English-language articles published between January 1960 and July 2020. Inclusion criteria encompassed randomized controlled trials (RCTs) that exclusively enrolled TBI patients, investigating various interventions, whether surgical or nonsurgical, and that were published in high-impact journals. Spin was defined as 1) a focus on statistically significant results not based on the primary outcome; 2) interpreting statistically nonsignificant results for a superiority analysis of the primary outcome; 3) claiming or emphasizing the beneficial effect of the treatment despite statistically nonsignificant results; 4) conclusion focused in the per-protocol or as-treated analysis instead of the intention-to-treat (ITT) results; 5) incorrect statistical analysis; or 6) republication of a significant secondary analysis without proper acknowledgment of the primary outcome analysis result. Primary outcomes were those explicitly reported as such in the published article. Studies without a clear primary outcome were excluded. The study characteristics were described using traditional descriptive statistics and an exploratory inferential analysis was performed to identify those associated with spin. The studies' risk of bias was evaluated by the Cochrane Risk of Bias Tool. RESULTS: A total of 150 RCTs were included and 22% (n = 33) had spin, most commonly spin types 1 and 3. The overall risk of bias (p < 0.001), a neurosurgery department member as the first author (p = 0.009), absence of a statistician among authors (p = 0.042), and smaller sample sizes (p = 0.033) were associated with spin. CONCLUSIONS: The prevalence of spin in the TBI literature is high, even at leading medical journals. Studies with higher risks of bias are more frequently associated with spin. Critical interpretation of results and authors' conclusions is advisable regardless of the study design and published journal.
ABSTRACT
Studies of the superior longitudinal fasciculus (SLF) have multiplied in recent decades owing to methodological advances, but the absence of a convention for nomenclature remains a source of confusion. Here, we have reviewed existing nomenclatures in the context of the research studies that generated them and we have identified their agreements and disagreements. A literature search was conducted using PubMed/MEDLINE, Web-of-Science, Embase, and a review of seminal publications, without restrictions regarding publication date. Our search revealed that diffusion imaging, autoradiography, and fiber dissection have been the main methods contributing to tract designation. The first two have been particularly influential in systematizing the horizontal elements distant from the lateral sulcus. Twelve approaches to naming were identified, eight of them differing considerably from each other. The terms SLF and arcuate fasciculus (AF) were often used as synonyms until the second half of the 20th century. During the last 15 years, this has ceased to be the case in a growing number of publications. The term AF has been used to refer to the assembly of three different segments, or exclusively to long frontotemporal fibers. Similarly, the term SLF has been employed to denote the whole superior longitudinal associative system, or only the horizontal frontoparietal parts. As only partial correspondence can be identified among the available nomenclatures, and in the absence of an official designation of all anatomical structures that can be encountered in clinical practice, a high level of vigilance regarding the effectiveness of every oral or written act of communication is mandatory.
