The Effects of Extinction in Multiple Spatial Contexts on Fear Recovery in Animals and Humans: a Meta-analysis Protocol

Abstract

\n BackgroundLaboratory studies that utilise an exposure-based approach seek to reduce recovery through repeated nonreinforced presentations of a fearful or appetitive stimulus. A recent meta-analysis on post-retrieval extinction revealed small and non-significant effects on fear recovery. While meta-analyses on the use of pharmacologic agents revealed promising results, deploying such methods as first-line treatment for anxiety disorders is not practicable. To date, there has not been a systematic review or meta-analysis conducted to evaluate the overall effectiveness of laboratory-based multiple spatial context extinction on fear renewal in animals or humans. The present paper provides a protocol for a systematic review and meta-analysis to synthesise current literature investigating fear extinction in multiple spatial contexts. This will help provide information into the types of circumstances required to effectively implement this manipulation as a clinical treatment for anxiety-based disorders.MethodsA literature search will be conducted on electronic databases with the addition of forward and backward reference checking. Only primary research empirical studies that investigated fear conditioning and manipulated extinction training over two or more spatial contexts will be included. Eligible studies must include at least one control group that received comparable extinction in one context. The population of the studies will include both human (non-clinical) and non-human animals (e.g. rats). There will be no limitations on publication date, country of origin, or language. Essential scores related to recovery will be recorded. Data will be extracted by one of the two reviewers and quality of studies will be assessed by both the Cochrane Risk of Bias tool version 2, for studies with human participants and the Systematic Review Centre for Laboratory Animal Experimentation risk of bias tool, for studies with animals. A three-level meta-analysis will be conducted to determine fear attenuating effects of extinction across multiple spatial contexts. Should moderate-high heterogeneity be found, causes will be investigated through subgroup analyses.DiscussionThe planned review will be the first to present a comprehensive evaluation of the current state of the effectiveness of conducting multiple spatial context extinction on the possible attenuation of conditioned fear. The review will determine the types of circumstances that may provide better efficacy into informing translational research into clinical exposure therapy for anxiety-based disorders.Systematic review registrationPROSPERO 142518, edited on 30th Oct 2020, pending approval.