Unravelling functional neurology: a critical review of clinical research articles on the effect or benefit of the functional neurology approach

BACKGROUND: Functional Neurology (FN), mainly practiced by chiropractors, proposes to have an effect or a benefit on varied clinical cases, from debilitating diseases to performance enhancement in asymptomatic people. OBJECTIVES AND DESIGN: A critical review of publications captured in and from the journal Functional Neurology, Rehabilitation, and Ergonomics (FNRE) was performed in order to investigate whether there is evidence on clinical effects or benefits of FN. This review had five research objectives, three relating to the type of literature available through this journal, and two in relation to design and methodological aspects of the included studies. METHOD: All issues of the FNRE journal were searched (October 2017), including a handsearch of their lists of other relevant publications. In order to find evidence in relation to the effect or benefit of FN, the search was restricted to prospective clinical research studies with a control group, claiming or appearing to deal with the topic. The review was undertaken by two independent reviewers using two checklists, one relating to study description, and one on quality. Results were reported narratively. RESULTS: Nine articles were found. The FNRE journal contained 168 authored texts, of which 36 were research studies (21%). Four of these were clinical research studies on FN effect or benefit (2%). Another five were obtained through the handsearch. The included studies were conducted on adults or children, symptomatic or not, and investigated various interventions consisting of single or multiple stimuli, of varied nature, all primarily said to be provided to stimulate brain areas. Conditions included attention deficit disorders, attention deficit and hyperactivity disorders, autism-spectrum disorders, cortical visual impairment, traumatic brain injury, and migraine. Balance and the “blind spot” were investigated in healthy subjects. Major design and methodological issues were identified and discussed for all the nine studies; only four were considered as (potentially) appropriate for further scrutiny. However, these were of low methodological quality and, therefore, no robust evidence could be found in relation to the effect or benefit of the tested FN interventions. CONCLUSIONS: This journal contains no acceptable evidence on the effect or benefit of FN in relation to various conditions and purported indications for intervention.