title: Investigation of the relationship between anxiety and heart rate variability in fibromyalgia: A new quantitative approach to evaluate anxiety level in fibromyalgia syndrome.
abstract: BACKGROUND
  Fibromyalgia syndrome (FMS) is identified by widespread musculoskeletal pain, sleep disturbance, nonrestorative sleep, fatigue, morning stiffness and anxiety. Anxiety is very common in Fibromyalgia and generally leads to a misdiagnosis. Self-rated Beck Anxiety Inventory (BAI) and doctor-rated Hamilton Anxiety Inventory (HAM-A) are frequently used by specialists to determine anxiety that accompanies fibromyalgia. However, these semi-quantitative anxiety tests are still subjective as the tests are scored using doctor-rated or self-rated scales.
  
  
  METHODS
  In this study, we investigated the relationship between heart rate variability (HRV) frequency subbands and anxiety tests. The study was conducted with 56 FMS patients and 34 healthy controls. BAI and HAM-A test scores were determined for each participant. ECG signals were then recruited and 71 HRV subbands were obtained from these ECG signals using Wavelet Packet Transform (WPT). The subbands and anxiety tests scores were analyzed and compared using multilayer perceptron neural networks (MLPNN).
  
  
  RESULTS
  The results show that a HRV high frequency (HF) subband in the range of 0.15235Hz to 0.40235Hz, is correlated with BAI scores and another HRV HF subband, frequency range of 0.15235Hz to 0.28907Hz is correlated with HAM-A scores. The overall accuracy is 91.11% for HAM-A and 90% for BAI with MLPNN analysis.
  
  
  CONCLUSIONS
  Doctor-rated or self-rated anxiety tests should be supported with quantitative and more objective methods. Our results show that the HRV parameters will be able to support the anxiety tests in the clinical evaluation of fibromyalgia. In other words, HRV parameters can potentially be used as an auxiliary diagnostic method in conjunction with anxiety tests.
authors.affiliation: Department of Electrical and Electronics Engineering, Faculty of Engineering, Akdeniz University, Antalya, Turkey. Electronic address: suleymanbilgin@akdeniz.edu.tr.
authors.forename: Suleyman
authors.initials: S
authors.lastname: Bilgin
authors.affiliation: Department of Electrical and Electronics Engineering, Faculty of Engineering, Sakarya University, Sakarya, Turkey. Electronic address: earslan@sakarya.edu.tr.
authors.forename: Evren
authors.initials: E
authors.lastname: Arslan
authors.affiliation: Department of Physiology, Faculty of Medicine, Mugla Sitki Kocman University, Mugla, Turkey. Electronic address: onurelmas@mu.edu.tr.
authors.forename: Onur
authors.initials: O
authors.lastname: Elmas
authors.affiliation: Suleyman Demirel University, Isparta, Turkey. Electronic address: dr_sedatyildiz@yahoo.com.
authors.forename: Sedat
authors.initials: S
authors.lastname: Yildiz
authors.affiliation: Department of Electrical and Electronics Engineering, Faculty of Engineering, Akdeniz University, Antalya, Turkey. Electronic address: omercol@akdeniz.edu.tr.
authors.forename: Omer H
authors.initials: OH
authors.lastname: Colak
authors.affiliation: Department of Industrial Electronics, Technical Vocational School, Mehmet Akif Ersoy University, Burdur, Turkey. Electronic address: gbilgin@mehmetakif.edu.tr.
authors.forename: Gurkan
authors.initials: G
authors.lastname: Bilgin
authors.affiliation: Department of Neurology, Faculty of Medicine, Suleyman Demirel University, Isparta, Turkey. Electronic address: hasanr@med.sdu.edu.tr.
authors.forename: Hasan Rifat
authors.initials: HR
authors.lastname: Koyuncuoglu
authors.affiliation: Suleyman Demirel University, Isparta, Turkey. Electronic address: selamiakkus@ybu.edu.tr.
authors.forename: Selami
authors.initials: S
authors.lastname: Akkus
authors.affiliation: Department of Electronics and Communication Engineering, Faculty of Engineering, Suleyman Demirel University, Isparta, Turkey. Electronic address: scom@mmf.sdu.edu.tr.
authors.forename: Selcuk
authors.initials: S
authors.lastname: Comlekci
authors.affiliation: Sakarya University, Sakarya, Turkey. Electronic address: ekoklukaya@gazi.edu.tr.
authors.forename: Etem
authors.initials: E
authors.lastname: Koklukaya
mesh_terms: D000465:Algorithms; D001007:Anxiety / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005260:Female; D005356:Fibromyalgia / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D016571:Neural Networks, Computer; D010363:Pattern Recognition, Automated / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
keywords: Auxiliary tests; Beck Anxiety Inventory (BAI); Electrocardiogram (ECG); Fibromyalgia Syndrome (FMS); Hamilton Anxiety Test (HAM-A); Heart Rate Variability (HRV); Multilayer Perceptron Neural Networks (MLPNN); Wavelet Packet Transform (WPT)