Biofeedback training on university student’s anxiety management: A systematic review

University students are susceptible to anxiety disorders. Nowadays it’s a growing problem, and cost-effective solutions are research’s imperative. Biofeedback training might be a valid solution to reduce anxiety and improve student’s health and performance. The aim of this paper is to do a reflective and systematic review of scientific literature about biofeedback application in anxiety management among university students. A Pubmed/Medline database research with the keywords “biofeedback” AND “anxiety” AND “students” were analysed in the period between 2015 and 1980 (all papers obtained). The PRISMA criteria for reporting in systematic reviews and meta-analyses were applied. The inclusion criteria were: the use of instruments to measure anxiety, the use of biofeedback applications, university student samples, the presentation of quantitative or qualitative results. It was excluded articles outside the scope of subject; that do not met the inclusion criteria; and papers without access. After applying this methodology, 17 scientific articles were included in the study. The instruments used, the dimensions, and the obtained results were analysed. This review allowed us to conclude that biofeedback can help university students to manage their anxiety and stress levels, but more research is needed to reinforce empirical evidence about biofeedback as a technique to improve students’ anxiety and stress. Correspondence to: Paulo Chaló, University of Aveiro, Education and Psychology Department, Campus Universitário de Santiago, 3810-193 Aveiro, Portugal, Tel: +351 234 370 353; Fax: +351 234 370 640; E-mail: paulo.chalo@ua.pt


Introduction
University students are susceptible to many stressors: new environment, difficult coursework, exams, time demands, financial pressure, changes in sleeping and eating habits, increased responsibilities, increased workload, meeting new people, career decisions, fear of failure and parental pressure [1,2].
Anxiety disorders are a growing problem in our society and are prevalent in university students, with more incidences at the first year [3]. Anxiety is an adaptive response to a perceived threat but beyond normal levels can lead to an out-of-proportion response, which can disrupt psychological functioning and manifest itself as physiological symptoms [1,4,5]. Therefore, anxiety and stress can affect academic performance, health, and well-being [6][7][8]. Given the pervasiveness of anxiety in student population, it is important to develop and implement interventions that can be easily used, inexpensive and have minimal side effects [3].
Since the 1960 's , biofeedback is being used to treat certain medical conditions and to improve human's health performance. Biofeedback can be described as a self-regulation process (mind-body) of the body's physiological functions, to improve performance and health [9].
Biofeedback equipment, include specialized devices and sensors, that transmit information about physiological process like heart rate, skin temperature, brainwave activity, blood pressure, respiration, or muscle activity. From the moment that the person become aware of his or her physiological function, he/she can learn to modify thoughts, feelings, or behaviours in order to make positive changes of that physiological activity to improve health and performance [10,11]. Therefore, biofeedback training has proved to be helpful in reducing anxiety/stress symptoms as well as other health conditions like asthma, attention deficit hyperactivity disorder, chronic pain, depression, epilepsy, headache, hypertension, insomnia, irritable bowel syndrome, posttraumatic stress disorder, stroke, and urinary incontinence [12].
There are many types of biofeedback: electroencephalograph (EEG), electrocardiogram (ECG), electromyography (EMG), electro dermal activity (EDA) and heart rate variability (HRV). These different types of biofeedback are used for different conditions. Interventions using biofeedback training can incorporate relaxation techniques to modify the autonomic nervous system by decreasing physiological arousal, leading to the decrease of stress/anxiety [10][11][12].
The aim of this study is to provide an overview of scientific evidence produced in "Biofeedback training on university student's anxiety management".

Methods
This paper is a reflective and systematic literature review study. Between 2015 and 1980, it was identified scientific papers published in international journals, using a digital format database research: MedLine and PubMed, and in a second phase it was used Scopus. The descriptors used in the research were: ["BIOFEEDBACK AND ANXIETY AND STUDENTS"], it was obtained 47 publications, in PubMed/MedLine database. All publications obtained in PubMed/ MedLine database were analysed, 30 publications were excluded: 10 publications were outside the scope of the study, out of context themes; 9 had anxiety students but no use of biofeedback techniques; 5 with no access; 3 reported students with anxiety and other pathologies; and 3 do not referred any university/college students.
This structured research resulted in 17 publications about the subject that were intended to assess and within inclusion criteria (see figure 1).
The inclusion and exclusion criteria of the studies are described in Table 1.
The PRISMA criteria for preferred reporting items of systematic reviews was applied. The information collected was compiled and analysed regarding the year of publication, authors, sample, and country, methodology, results and aims.
The cataloguing and identification of repeated references were made through the computer program EndNote bibliographic referencing.

Analysis of results and discussion
The present review revealed few studies about this issue: "Biofeedback training on university student's anxiety management". For a brief summary, the analysed studies were grouped by decade and compiled in a summary table (Table 2).
A wide number of studies (9) took place between 1980 and 1989 (53%), after that and over the next 20 years (1990 to 2009) only one study (6%) was found, and recently the number of studies seemed to increase with 7 studies (41%) over the last 5 years (2010 to 2015).
For a better understanding of the systematic literature review, the analysed studies were compiled in a summary table (

Inclusion Criteria Exclusion Criteria
Use of instruments to measure anxiety No use of instruments to measure anxiety or used on non-university students Use of biofeedback in university students No use of biofeedback or used on non-university students Anxiety students with others pathologies Presentation/analysing quantitative/qualitative data No presentation/analysing quantitative/qualitative data Incomplete studies/without accessibility  (1) IPAT Anxiety Scale (1) -Compare the efficacy between brief intervention programs (biofeedback and mindfulness) on levels of state anxiety and perceived stress in students.
N=89 nursing college students.
-The biofeedback and mindfulness groups received two training sessions. -The control group took no action. -Participants in both intervention groups were instructed to use their taught intervention three times per day for 4 weeks.
-Biofeedback significantly reduced anxiety and maintained stress levels in students. -Mindfulness meditation similarly decreased anxiety levels, while also significantly lowering stress levels.
-The biofeedback group exhibited significant reduction in anxiety levels among the three groups at post intervention. First study: -promising results and suggested that participating in the HeartMath computerbased biofeedback intervention resulted in a significant reduction in self-reported levels of anxiety and negative mood.
Second study: -biofeedback program does reduce levels of anxiety. -no evidence that the program increased positive mood or general domains of well-being.- STAI. Biofeedback (EMG).
-Pre and post anxiety scores indicated a reduction in self-reported state anxiety for all groups combined, but no differential reductions with respect to group or condition. -Explore and compare the effects of cognitive imagery relaxation and biofeedback relaxation protocols. -Examine changes in identified tension behaviors, and assess changes across several related and unrelated personality dimensions.
N=45 female students volunteers.
-During three weekly sessions each per-son received either guided cognitive imagery relaxation, frontalis muscle feedback relaxation, or a selfrest control procedure.
Taylor-Johnson Temperament Analysis.
-Imagery procedure was associated with moderate reductions in physiological tension and significant reductions in state anxiety and three tension-related personality dimension. -Biofeedback persons showed the largest reductions in physiological tension, they displayed only small and variable changes in state anxiety and personality dimension. -Self-rest persons displayed lesser reductions in general tension with little physiological change.
McKinney & Gatchel, 1982, USA. [23] -Evaluate the effectiveness of biofeedback, Speech Skills Training, and a combination of both in treating public-speaking anxiety.
-After e relaxation session, each group: (biofeedback training, speech skills training, and a combination of both) received a different intervention over the next 4 sessions.
-All treatments were effective in lowering overt motor and self-report components of anxiety. -Only the biofeedback and combined group subjects demonstrated significantly less heart rate increase while speaking before an audience during the post treatment assessment. -Examines the relative efficacy of an in vivo distraction-coping training procedure, explicitly designed to provide test anxious students with attentional focusing skills, when added to a standard cognitive-behavioral test anxiety reduction program.
-Control group received core treatment program of: cognitive behavior therapy, progressive muscular relaxation training, and thermal biofeedback. -The experimental group received core treatment and additional in yivo distractioncoping training.

Rational Behavior
Inventory. Biofeedback (Thermal) -Overall the efficacy of the core program was demonstrated with reductions in test, trait and state anxiety, and increases in personal belief systems. -In vivo distraction-coping was not found to result in more efficacious treatment as measured by self-report and performance variables. -Hypnosis was a more effective selfregulatory technique for lowering anxiety levels when compared to biofeedback or trophotropic response procedures.
-To increasing ego strength, both the hypnotic training group and the biofeedback training group proved to be significant.
improve anxiety or stress.
Five studies analysed only biofeedback intervention. Four studies presented a significant reduction of measured anxiety levels after biofeedback intervention [3,[13][14][15][16], and one found no significant differences on anxiety self-reported measures after biofeedback training but there was a reduction on physiological responses to stress [5].
The use of biofeedback with other forms of intervention was found on 6 articles. All studies presented a reduction of the measured anxiety levels for programs of biofeedback combined with: Stroebel's Quieting Response [4]; an attention-training program [17]; Benson's technique [18], a common core treatment program of cognitive behaviour therapy, progressive muscular relaxation and biofeedback [19], with 1-year follow-up [20]; and progressive relaxation [21].
Biofeedback alone was also compared with other techniques on 6 studies. When compared with a self-paced exercise program, biofeedback decreased anxiety and increased calmness [22]. Another study compared biofeedback and mindfulness, both reduced anxiety but mindfulness significantly lowered stress levels while biofeedback maintained them [8]. Lee et al. [1] compared biofeedback and relaxation training and found that, despite no differences were found between these interventions, only biofeedback presented significant reduction when compared with the control group. McKinney and Gatchel [23] concluded that biofeedback as well as speech skills training were effective on reducing anxiety. Different results were found in a study where biofeedback displayed little change in Anxiety Differential scores when compared with imagery relaxation [24]. Hurley [25] also found hypnosis to be a more effective self-regulatory technique when compared to biofeedback.
It is important to highlight that 2010 seem to mark a return of research on this specific filed. After the period between 1980 and 1989, when were published most of the analysed articles, the research seem to almost stop. Two justifications help explain it. First, the increasing anxiety in university students, and the personal, social and economic consequences, makes this subject more relevant. Second, the traditional biofeedback involved complex multi-channel input and presented a cost that was prohibitive for many campuses, but in recent years new low cost, portable, more accurate and friendly-user devices have been developed and allowed biofeedback to expand [9].

Summary of methodological limitations
The selected methodology for the inclusion and exclusion criteria of the current study always limits the obtained results. It can leave out many valid data studies and relevant factors to the understanding of the theme can be excluded. The lack of publications in this area, also conditioned the selection, analysis and generalization of results.
We found limitations in the analysed articles: not representative sample of population or small sample size [1,3,4,[15][16][17], short treatment duration; incomplete data follow-up or lack of follow-up on the long-term impact of biofeedback on anxiety [16]; preliminary study [14]; insufficient available statistical evidence [17]; unable to conduct analyses corresponding the changes in self-report with the coherence data recorded by computer-based biofeedback program [3].

Implications for practice
High anxiety is a growing problem in society and in university students. Consequently this disorder can affect academic performance, health and quality of life/well-being.
This literature review aimed to present the information obtained about "Biofeedback training on university student's anxiety management". Despite of the scarce publications found, this study intended to find what has be done and highlight what should be done.
Most studies have reported that biofeedback training has demonstrated to be an effective form of intervention to help graduate students to significantly reduce their levels of stress and anxiety, but more researches are needed because there are only few systematic studies on this field. doi: 10.15761/BRCP.1000129 Volume 2(1): 6-6 The current review suggests new studies about biofeedback training and longitudinal studies, to analyse the implications over time. Furthermore, it is important to extend these studies to other countries.
It is important to explore effective and accessible strategies to help students to decrease anxiety symptoms, to reduce physiological activation and improve psychological well-being. Therefore, developing interventions that cost-effective and that can be easily implemented may be valuable in educational environments, and biofeedback intervention can be a solution to help those students [15].

Conclusion
From the present study, we can conclude that biofeedback training can be effectively used as an effective tool to decrease anxiety and stress symptoms, and could play an important role on campus health cares.
This study sought to address the issue and intended to draw attention to the importance of recognizing this problem of society.
Thus, more research is needed, more interventions/programs, and more tools are needed to assess the impact of biofeedback applications in anxiety treatments in university students, improving health behaviours and the quality of life of these students. It is important to have academic programs to take action and help students acquire skills to improve their physical and emotional health.