muscle pain budzynski and stoyva (1969) showed that emg biofeedback could reduce frontalis muscle (forehead) contraction. they demonstrated in 1973 that analog (proportional) and binary (on or off) visual emg biofeedback were equally helpful in lowering masseter semg levels. mcnulty, gevirtz, hubbard, and berkoff (1994) proposed that sympathetic nervous system innervation of muscle spindles underlies trigger points. tension headache budzynski, stoyva, adler, and mullaney (1973) reported that auditory frontalis emg biofeedback combined with home relaxation practice lowered tension headache frequency and frontalis emg levels. a control group that received noncontingent (false) auditory feedback did not improve. this study helped make the frontalis muscle the placement-of-choice in emg assessment and treatment of headache and other psychophysiological disorders. migraine sargent, green, and walters (1972, 1973) demonstrated that hand-warming could abort migraines and that autogenic biofeedback training could reduce headache activity. the early menninger migraine studies, although methodologically weak (no pretreatment baselines, control groups, or random assignment to conditions), strongly influenced migraine treatment. a 2013 review classified biofeedback among the techniques that might be of benefit in the management of chronic migraine. phantom-limb pain flor (2002) trained amputees to detect the location and frequency of shocks delivered to their stumps, which resulted in an expansion of corresponding cortical regions and significant reduction of their phantom limb pain. financial decision-making financial traders use biofeedback as a tool for regulating their level of emotional arousal in order to make better financial decisions. the technology company philips and the dutch bank abn amro developed a biofeedback device for retail investors based on a galvanic skin response sensor. astor et al. (2013) developed a biofeedback based serious game in which financial decision makers can learn how to effectively regulate their emotions using heart rate measurements. stress reduction a randomized study by sutarto et al. assessed the effect of resonant breathing biofeedback (recognize and control involuntary heart rate variability) among manufacturing operators; depression, anxiety and stress significantly decreased. heart rate variability data can be analyzed with deep neural networks to accurately predict stress levels. this technology is utilized in a mobile app in combination with mindfulness techniques to effectively promote stress reduction. anxiety management a meta analysis by the university of cambridge compiles previous studies on biofeedback being used in the management and control of anxiety. in this article the previous studies are evaluated for validity and relevance into how they attribute to the effectiveness of biofeedback being used in tandem with other forms of therapy to produce reduced and manageable anxiety. this analysis concluded that the use of biofeedback in the form of hrv monitoring produced self reported large reduction of anxiety as a consistent finding in the studies that were a part of the meta analysis. relaxation in a study of 18 healthy individuals published in the international journal of stress management it was established that with the use of biofeedback there were large improvements in the individuals ability to relax which was translated in the individuals having improved scores on the smith relaxation states inventory 3 test which measures mindfulness, energized positive feelings and basic relaxation. macular disease of the retina a 2012 observational study by pacella et al. found a significant improvement in both visual acuity and fixation treating patients with age-related macular degeneration or macular degeneration with biofeedback treatment through mp-1 microperimeter. clinical effectiveness research moss, levaque, and hammond (2004) observed that "biofeedback and neurofeedback seem to offer the kind of evidence-based practice that the healthcare establishment is demanding." "from the beginning biofeedback developed as a research-based approach emerging directly from laboratory research on psychophysiology and behavior therapy. the ties of biofeedback/neurofeedback to the biomedical paradigm and to research are stronger than is the case for many other behavioral interventions" (p. 151). the association for applied psychophysiology and biofeedback (aapb) and the international society for neurofeedback and research (isnr) have collaborated in validating and rating treatment protocols to address questions about the clinical efficacy of biofeedback and neurofeedback applications, like adhd and headache. in 2001, donald moss, then president of the association for applied psychophysiology and biofeedback, and jay gunkelman, president of the international society for neurofeedback and research, appointed a task force to establish standards for the efficacy of biofeedback and neurofeedback. the task force document was published in 2002, and a series of white papers followed, reviewing the efficacy of a series of disorders. the white papers established the efficacy of biofeedback for functional anorectal disorders, attention deficit disorder, facial pain and temporomandibular joint dysfunction, hypertension, urinary incontinence, raynaud's phenomenon, substance abuse, and headache. a broader review was published and later updated, applying the same efficacy standards to the entire range of medical and psychological disorders. the 2008 edition reviewed the efficacy of biofeedback for over 40 clinical disorders, ranging from alcoholism/substance abuse to vulvar vestibulitis. the ratings for each disorder depend on the nature of research studies available on each disorder, ranging from anecdotal reports to double blind studies with a control group. thus, a lower rating may reflect the lack of research rather than the ineffectiveness of biofeedback for the problem. the randomized trial by dehli et al. compared if the injection of a bulking agent in the anal canal was superior to sphincter training with biofeedback to treat fecal incontinence. both methods lead to an improvement of fi, but comparisons of st mark's scores between the groups showed no differences in effect between treatments. following their reviews, the national institute for health and care excellence have recommended against the use of biofeedback in the treatment of constipation in children, urinary incontinence in women, and chronic pain. efficacy yucha and montgomery's (2008) ratings are listed for the five levels of efficacy recommended by a joint task force and adopted by the boards of directors of the association for applied psychophysiology (aapb) and the international society for neuronal regulation (isnr). from weakest to strongest, these levels include: not empirically supported, possibly efficacious, probably efficacious, efficacious, and efficacious and specific. level 1: not empirically supported. this designation includes applications supported by anecdotal reports and/or case studies in non-peer-reviewed venues. yucha and montgomery (2008) assigned eating disorders, immune function, spinal cord injury, and syncope to this category. level 2: possibly efficacious. this designation requires at least one study of sufficient statistical power with well-identified outcome measures but lacking randomized assignment to a control condition internal to the study. yucha and montgomery (2008) assigned asthma, autism, bell palsy, cerebral palsy, copd, coronary artery disease, cystic fibrosis, depression, erectile dysfunction, fibromyalgia, hand dystonia, irritable bowel syndrome, ptsd, repetitive strain injury, respiratory failure, stroke, tinnitus, and urinary incontinence in children to this category. level 3: probably efficacious. this designation requires multiple observational studies, clinical studies, waitlist-controlled studies, and within subject and intrasubject replication studies that demonstrate efficacy. yucha and montgomery (2008) assigned alcoholism and substance abuse, arthritis, diabetes mellitus, fecal disorders in children, fecal incontinence in adults, insomnia, pediatric headache, traumatic brain injury, urinary incontinence in males, and vulvar vestibulitis (vulvodynia) to this category. level 4: efficacious. this designation requires the satisfaction of six criteria: (a) in a comparison with a no-treatment control group, alternative treatment group, or sham (placebo) control using randomized assignment, the investigational treatment is shown to be statistically significantly superior to the control condition or the investigational treatment is equivalent to a treatment of established efficacy in a study with sufficient power to detect moderate differences. (b) the studies have been conducted with a population treated for a specific problem, for whom inclusion criteria are delineated in a reliable, operationally defined manner. (c) the study used valid and clearly specified outcome measures related to the problem being treated. (d) the data are subjected to appropriate data analysis. (e) the diagnostic and treatment variables and procedures are clearly defined in a manner that permits replication of the study by independent researchers. (f) the superiority or equivalence of the investigational treatment has been shown in at least two independent research settings. yucha and montgomery (2008) assigned attention deficit hyperactivity disorder (adhd), anxiety, chronic pain, epilepsy, constipation (adult), headache (adult), hypertension, motion sickness, raynaud's disease, and temporomandibular joint dysfunction to this category. level 5: efficacious and specific. the investigational treatment must be shown to be statistically superior to credible sham therapy, pill, or alternative bona fide treatment in at least two independent research settings. yucha and montgomery (2008) assigned urinary incontinence (females) to this category. criticisms in a healthcare environment that emphasizes cost containment and evidence-based practice, critics question how these treatments compare with conventional behavioral and medical interventions on efficacy and cost. a review of a meta-analysis of biofeedback treatments noted the lack of comparisons with existing treatments in most of the studies included. organizations the association for applied psychophysiology and biofeedback (aapb) is a non-profit scientific and professional society for biofeedback and neurofeedback. the international society for neurofeedback and research (isnr) is a non-profit scientific and professional society for neurofeedback. the biofeedback foundation of europe (bfe) sponsors international education, training, and research activities in biofeedback and neurofeedback. the northeast regional biofeedback association (nrbs) sponsors theme-centered educational conferences, political advocacy for biofeedback friendly legislation, and research activities in biofeedback and neurofeedback in the northeast regions of the united states. the southeast biofeedback and clinical neuroscience association (sbcna) is a non-profit regional organization supporting biofeedback professionals with continuing education, ethics guidelines, and public awareness promoting the efficacy and safety of professional biofeedback. the sbcna offers an annual conference for professional continuing education as well as promoting biofeedback as an adjunct to the allied health professions. the sbcna was formally the north carolina biofeedback society (ncbs), serving biofeedback since the 1970s. in 2013, the ncbs reorganized as the sbcna supporting and representing biofeedback and neurofeedback in the southeast region of the united states of america. certification the biofeedback certification international alliance (formerly the biofeedback certification institute of america) is a non-profit organization that is a member of the institute for credentialing excellence (ice). bcia offers biofeedback certification, neurofeedback (also called eeg biofeedback) certification, and pelvic muscle dysfunction biofeedback. bcia certifies individuals meeting education and training standards in biofeedback and neurofeedback and progressively recertifies those satisfying continuing education requirements. bcia certification has been endorsed by the mayo clinic, the association for applied psychophysiology and biofeedback (aapb), the international society for neurofeedback and research (isnr), and the washington state legislature. the bcia didactic education requirement includes a 48-hour course from a regionally-accredited academic institution or a bcia-approved training program that covers the complete general biofeedback blueprint of knowledge and study of human anatomy and physiology. the general biofeedback blueprint of knowledge areas include: i. orientation to biofeedback, ii. stress, coping, and illness, iii. psychophysiological recording, iv. surface electromyographic (semg) applications, v. autonomic nervous system (ans) applications, vi. electroencephalographic (eeg) applications, vii. adjunctive interventions, and viii. professional conduct. applicants may demonstrate their knowledge of human anatomy and physiology by completing a course in human anatomy, human physiology, or human biology provided by a regionally-accredited academic institution or a bcia-approved training program or by successfully completing an anatomy and physiology exam covering the organization of the human body and its systems. applicants must also document practical skills training that includes 20 contact hours supervised by a bcia-approved mentor designed to them teach how to apply clinical biofeedback skills through self-regulation training, 50 patient/client sessions, and case conference presentations. distance learning allows applicants to complete didactic course work over the internet. distance mentoring trains candidates from their residence or office. they must recertify every 4 years, complete 55 hours of continuing education during each review period or complete the written exam, and attest that their license/credential (or their supervisor's license/credential) has not been suspended, investigated, or revoked. history claude bernard proposed in 1865 that the body strives to maintain a steady state in the internal environment (milieu intérieur), introducing the concept of homeostasis. in 1885, j.r. tarchanoff showed that voluntary control of heart rate could be fairly direct (cortical-autonomic) and did not depend on "cheating" by altering breathing rate. in 1901, j. h. bair studied voluntary control of the retrahens aurem muscle that wiggles the ear, discovering that subjects learned this skill by inhibiting interfering muscles and demonstrating that skeletal muscles are self-regulated. alexander graham bell attempted to teach the deaf to speak through the use of two devices—the phonautograph, created by édouard-léon scott's, and a manometric flame.