Rheumatology International

, Volume 35, Issue 7, pp 1115–1125 | Cite as

Fibrofog and fibromyalgia: a narrative review and implications for clinical practice

  • Howard M. KravitzEmail author
  • Robert S. Katz
Review Article - Food for Thought


Patients with fibromyalgia often report forgetfulness as well as declines in cognitive function, memory, and mental alertness—symptoms that have been termed “fibrofog” in popular and electronic media as well as in professional literature. “Fibrofog” is the subjectively experienced cognitive dysfunction associated with fibromyalgia and is a clinically important yet comparatively less well-studied aspect of the disorder; it includes loss of mental clarity (mental fogginess) as well as attention and memory impairment. Although until recently cognitive symptoms have been largely ignored, these symptoms can be more disturbing than the widespread pain and can change these patients’ lives, sometimes dramatically so. Whereas widespread musculoskeletal pain, tenderness, and fatigue may be the hallmark symptoms of fibromyalgia, patients rank cognitive dysfunction highly in terms of disease impact. This review addresses (1) the prevalence of self-reported cognitive disturbances in fibromyalgia, (2) the clinical presentation of fibrofog, (3) neuropsychological test performance, with particular attention to discrepancies between self-report and test results, (3) clinical correlates of impaired cognitive function in fibromyalgia, (4) neurobiology relevant to cognitive disturbances in fibromyalgia, and (5) clinical management of fibrofog. Although the pathophysiology of fibromyalgia remains an enigma, evidence suggests that it may be a brain disorder, with cognitive deficits (“fibrofog”) reflecting disturbed centrally mediated processes.


Cognitive dysfunction Concentration Distraction Fibrofog Fibromyalgia Memory 


Conflict of interest

The authors declare no conflict of interest.


  1. 1.
    Arnold LM, Crofford LJ, Mease PJ, Burgess SM, Palmer SC, Abetz L, Martin SA (2008) Patient perspectives on the impact of fibromyalgia. Patient Educ Couns 73:114–120CrossRefPubMedCentralPubMedGoogle Scholar
  2. 2.
    Bennett RM, Jones J, Turk DC, Russell IJ, Matallana L (2007) An internet survey of 2,596 people with fibromyalgia. BMC Musculosket Dis 8:27CrossRefGoogle Scholar
  3. 3.
    Glass JM, Park DC, Minear M, Crofford LJ (2005) Memory beliefs and function in fibromyalgia patients. J Psychosom Res 58:263–269CrossRefPubMedGoogle Scholar
  4. 4.
    Grace GM, Nielson WR, Hopkins M, Berg MA (1999) Concentration and memory deficits in patients with fibromyalgia syndrome. J Clin Exp Neuropsychol 21:477–487CrossRefPubMedGoogle Scholar
  5. 5.
    Katz RS, Heard AR, Mills M, Leavitt F (2004) The prevalence and clinical impact of reported cognitive difficulties (Fibrofog) in patients with rheumatic disease with and without fibromyalgia. J Clin Rheumatol 10:53–58CrossRefPubMedGoogle Scholar
  6. 6.
    Mease PJ, Clauw DJ, Arnold LM, Goldenberg DL, Witter J, Williams DA, Simon LS, Strand CV, Bramson C, Martin S, Wright TM, Littman B, Wernicke JF, Gendreau RM, Crofford LJ (2005) Fibromyagia syndrome. J Rheumatol 32:2270–2277PubMedGoogle Scholar
  7. 7.
    Pincus T, Swearington C, Callahan LF (1996) A self-report cognitive symptoms inventory to assess patients with rheumatic disease: results in eosinophilic-myalgia syndrome, fibromyalgia, rheumatoid arthritis, and other rheumatic diseases [abstract]. Arthritis Rheum 39(Suppl):S261Google Scholar
  8. 8.
    Zachrisson O, Regland B, Jahreskog M, Kron M, Gottfries CG (2002) A rating scale for fibromyalgia and chronic fatigue syndrome (the FibroFatigue scale). J Psychosom Res 52:501–509CrossRefPubMedGoogle Scholar
  9. 9.
    Glass JM (2006) Cognitive dysfunction in fibromyalgia and chronic fatigue syndrome: new trends and future directions. Curr Rheumatol Rep 8:425–429CrossRefPubMedGoogle Scholar
  10. 10.
    Wolfe F, Clauw DJ, Fitzcharles M-A, Goldenberg DL, Katz RS, Mease P, Russell AS, Russell IJ, Winfield JB, Yunus MB (2010) The American College of Rheumatology preliminary diagnostic criteria for fibromyalgia and measurement of symptom severity. Arthritis Care Res 62:600–610CrossRefGoogle Scholar
  11. 11.
    Wolfe F, Clauw DJ, Fitzcharles M-A, Goldenberg DL, Hauser W, Katz RS, Mease P, Russell AS, Russell IJ, Winfield JB (2011) Fibromyalgia criteria and severity scales for clinical and epidemiological studies: a modification of the ACR preliminary diagnostic criteria for fibromyalgia. J Rheumatol 38:1113–1122CrossRefPubMedGoogle Scholar
  12. 12.
    Mease PJ, Arnold LM, Choy EH, Clauw DJ, Crofford LJ, Glass JM, Martin SA, Morea J, Simon L, Strand CV (2009) OMERACT Fibromyalgia Working Group. Fibromyalgia syndrome module at OMERACT 9: domain construct. J Rheumatol 36:2318–2329CrossRefPubMedCentralPubMedGoogle Scholar
  13. 13.
    Fries J, Bruce B, Cella D (2005) The promise of PROMIS: using item response theory to improve assessment of patient-reported outcomes. Clin Exp Rheumatol 23:S53–S57PubMedGoogle Scholar
  14. 14.
    Glass JM, Park DC (2001) Cognitive dysfunction in fibromyalgia. Curr Rheumatol Rep 3:123–127CrossRefPubMedGoogle Scholar
  15. 15.
    Glass JM, Park DC, Crofford LJ (2000) Metamemory in fibromyalgia [abstract]. Arthritis Rheum 43(Suppl):S209Google Scholar
  16. 16.
    Park DC, Glass JM, Minear M, Crofford LJ (2001) Cognitive function in fibromyalgia patients. Arthritis Rheum 44:2125–2133CrossRefPubMedGoogle Scholar
  17. 17.
    Mease PJ, Arnold LM, Crofford LJ, Williams DA, Russell IJ, Humphrey L, Abetz L, Martin SA (2008) Identifying the clinical domains of fibromyalgia: contributions from clinician and patient Delphi exercises. Arthritis Care Res (Hoboken) 59:952–960CrossRefGoogle Scholar
  18. 18.
    Donaldson CCS, Sella GE, Mueller HH (1998). Fibromyalgia. A retrospective study of 252 consecutive referrals. Can J Clin Med 5:116–121, 124–127Google Scholar
  19. 19.
    Leavitt F, Katz RS (2011) Development of the Mental Clutter Scale. Psychol Rep 109:1–8CrossRefGoogle Scholar
  20. 20.
    Katz RS, Leavitt F (2014) Fibro fog: when fibromyalgia affects your thinking. Arthritis Self-Manag 16:17–19Google Scholar
  21. 21.
    Dickson B, Eccleston C, Crombez G (2002) Attentional functioning in fibromyalgia, rheumatoid arthritis and musculoskeletal pain patients. Arthritis Rheum 6:639–644Google Scholar
  22. 22.
    Glass JM (2008) Fibromyalgia and cognition. J Clin Psychiatry 69(Suppl 2):20–24PubMedGoogle Scholar
  23. 23.
    Leavitt F, Katz RS (2006) Distraction as a key determinant of impaired memory in patients with fibromyalgia. J Rheumatol 33:127–132PubMedGoogle Scholar
  24. 24.
    Dick B, Eccleston C, Crombez G (2002) Attentional functioning in fibromyalgia, rheumatoid arthritis, and musculoskeletal pain patients. Arthritis Care Res (Hoboken) 47:639–644CrossRefGoogle Scholar
  25. 25.
    Glass JM (2009) Review of cognitive dysfunction in fibromyalgia: a convergence on working memory and attentional control impairments. Rheum Dis Clin N Am 35:299–311CrossRefGoogle Scholar
  26. 26.
    Leavitt F, Katz RS, Mills M, Heard AR (2002) Cognitive and dissociative manifestations in fibromyalgia. J Clin Rheumatol 8:77–84CrossRefPubMedGoogle Scholar
  27. 27.
    Leavitt F, Katz RS (2008) Speed of mental operations in fibromyalgia: a selective naming speed deficit. J Clin Rheumatol 14:214–218PubMedGoogle Scholar
  28. 28.
    Miro E, Lupianez J, Hita E, Martinez MP, Sanchez AI, Buela-Casal G (2011) Attentional deficits in fibromyalgia and its relationships with pain, emotional distress and sleep dysfunction complaints. Psychol Health 26:765–780CrossRefPubMedGoogle Scholar
  29. 29.
    McDermid AJ, Rollman GB, McCain GA (1996) Generalized hypervigilance in fibromyalgia: evidence of perceptual amplification. Pain 66:133–144CrossRefPubMedGoogle Scholar
  30. 30.
    Katz RS, Small BJ, Shott S, Ferbert SM (2012) Hypervigilance in fibromyalgia [abstract 1858]. Arthritis Rheum 64(Suppl):S790–S791Google Scholar
  31. 31.
    Higgins ES, George MS (2013) Attention. In: The neuroscience of clinical psychiatry: the pathophysiology of behavior and mental illness, 2nd edn. Lippincott Williams & Wilkins, Philadelphia, pp 240–250Google Scholar
  32. 32.
    Jonides J (1995) Working memory and thinking. In: Osherson DN, Smith EE, Gleitman LR (eds) An invitation to cognitive science: thinking. MIT Press, Cambridge, pp 215–265Google Scholar
  33. 33.
    Cherry BJ, Zettel-Watson L, Shimizu R, Roberson I, Rutledge DN, Jones CJ (2014) Cognitive performance in women aged 50 years and older with and without fibromyalgia. J Gerontol B Psychol Sci Soc Sci 69:199–208CrossRefPubMedCentralPubMedGoogle Scholar
  34. 34.
    Sletvold H, Stiles TC, Landro NI (1995) Information processing in primary fibromyalgia, major depression and healthy controls. J Rheumatol 22:137–142PubMedGoogle Scholar
  35. 35.
    Robertson IH, Ward T, Ridgeway V, Nimmo-Smith I (1994) The test of everyday attention. Thames Valley Test Company, SuffolkGoogle Scholar
  36. 36.
    Katz RS, Leavitt F (2013) Cross-sectional neurocognitive data do not support a transition from fibrofog to Alzheimer disease in fibromyalgia patients [abstract 133]. Arthritis Rheum 65(Suppl):S53–S54Google Scholar
  37. 37.
    Ambrose KR, Gracely RH, Glass JM (2012) Fibromyalgia dyscognition: concepts and issues. Reumatismo 64:206–215CrossRefPubMedGoogle Scholar
  38. 38.
    Park DC (2000) The basic mechanisms accounting for age-related decline in cognitive function. In: Park DC, Schwarz N (eds) Cognitive aging: a primer. Psychology Press, Philadelphia, pp 3–22Google Scholar
  39. 39.
    Park DC, Smith AD, Lautenschlager G, Earles JL, Frieske D, Zwahr M, Gaines CL (1996) Mediators of long-term memory performance across the life span. Psychol Aging 11:621–637CrossRefPubMedGoogle Scholar
  40. 40.
    Salthouse TA (1996) The processing-speed theory of adult age differences in cognition. Psychol Rev 103:403–428CrossRefPubMedGoogle Scholar
  41. 41.
    Kuchinad A, Schweinhardt P, Seminowicz DA, Wood PB, Chizh BA, Bushnell MC (2007) Accelerated brain gray matter loss in fibromyalgia patients: premature aging of the brain? J Neurosci 27:4004–4007CrossRefPubMedGoogle Scholar
  42. 42.
    Bowers PG, Steffy RA, Tate E (1988) Comparison of the effects of IQ control methods on memory and naming speed predictors of reading disability. Read Res Q 23:304–319CrossRefGoogle Scholar
  43. 43.
    Brouwer WH (1985) Limitations of attention after closed head injury: detection and 0.10 Hz heart rate variability in low event rate vigilance task. Cortex 21:111–119CrossRefPubMedGoogle Scholar
  44. 44.
    Kello CT (2004) Control over the time course of cognition in the tempo-naming task. J Exp Psychol Hum Percept Perform 30:942–955CrossRefPubMedGoogle Scholar
  45. 45.
    Hasher L, Zacks RT (1979) Automatic and effortful processes in memory. J Exp Psychol 108:356–388CrossRefGoogle Scholar
  46. 46.
    Gervais RO, Russell AS, Green P, Allen LM, Ferrari R, Pieschl SD (2001) Effort testing in patients with fibromyalgia and disability incentives. J Rheumatol 28:1892–1899PubMedGoogle Scholar
  47. 47.
    Duschek S, Wener NS, Winkelmann A, Wankner S (2013) Implicit memory function in fibromyalgia syndrome. Behav Med 39:11–16CrossRefPubMedGoogle Scholar
  48. 48.
    Baddeley A, Eysenck MW, Anderson MC (2009) Memory. Psychology Press Ltd, New YorkGoogle Scholar
  49. 49.
    Seidenberg M, Haltiner A, Taylor MA, Hermann BB, Wyler A (1994) Development and validation of a Multiple Ability Self-Report Questionnaire. J Clin Exp Neuropsychol 16:93–104CrossRefPubMedGoogle Scholar
  50. 50.
    Williams DA, Clauw DJ, Glass JM (2011) Perceived cognitive dysfunction in fibromyalgia syndrome. J Musculoskel Pain 19:66–75CrossRefGoogle Scholar
  51. 51.
    Dick BD, Verrier MJ, Harker KT, Rashiq S (2008) Disruption of cognitive function in fibromyalgia syndrome. Pain 139:610–616CrossRefPubMedGoogle Scholar
  52. 52.
    Sephton SE, Studts JL, Hoover K, Weissbecker I, Lynch G, Ho I, McGuffin S, Salmon PG (2003) Biological factors associated with memory function in fibromyalgia syndrome. Health Psychol 22:592–597CrossRefPubMedGoogle Scholar
  53. 53.
    Staud R (2002) Evidence of involvement of central neural mechanisms in generating fibromyalgia pain. Curr Rheumatol Rep 4:299–305CrossRefPubMedGoogle Scholar
  54. 54.
    Wolfe F, Smythe HA, Yunus MB, Bennett RM, Bombardier C, Goldenberg DL, Tugwell P, Campbell SM, Abeles M, Clark P, Fam AG, Farber SJ, Fiechtner JJ, Franklin CM, Gatter RA, Hamaty D, Lessard J, Lichtbroun AS, Masi AT, McCain GA, Reynolds WJ, Romano TJ, Russell IJ, Sheon RP (1990) The American College of Rheumatology 1990 criteria for the classification of fibromyalgia. Report of the Multicenter Criteria Committee. Arthritis Rheum 33:160–172CrossRefPubMedGoogle Scholar
  55. 55.
    Eccleston C (1994) Chronic pain and attention: a cognitive approach. Br J Clin Psychol 33:535–547CrossRefPubMedGoogle Scholar
  56. 56.
    Arnold LM, Hudson JI, Keck PE Jr, Auchenbach MB, Javaras KN, Hess EV (2006) Comorbidity of fibromyalgia and psychiatric disorders. J Clin Psychiatry 67:1219–1225CrossRefPubMedGoogle Scholar
  57. 57.
    Landro NI, Stiles TC, Sletvold H (1997) Memory functioning in patients with primary fibromyalgia and major depression and healthy controls. J Psychosom Res 42:297–306CrossRefPubMedGoogle Scholar
  58. 58.
    Suhr J (2003) Neuropsychological impairment in fibromyalgia. Relation to depression, fatigue, and pain. J Psychosom Res 55:321–329CrossRefPubMedGoogle Scholar
  59. 59.
    Reyes del Paso GA, Pulgar A, Duschek S, Garrido S (2012) Cognitive impairment in fibromyalgia syndrome: the impact of cardiovascular regulation, pain, emotional disorders and medication. Eur J Pain 16:421–429CrossRefPubMedGoogle Scholar
  60. 60.
    Verdejo-Garcia A, Lopez-Torrecillas F, Calandre EP, Delgado-Rodriguez A, Bechara A (2009) Executive function and decision-making in women with fibromyalgia. Arch Clin Neuropsychol 24:113–122CrossRefPubMedGoogle Scholar
  61. 61.
    Seo J, Kim S-H, Kim Y-T, Song H-j, Lee J-j, Kim S-H, Han SW, Nam EJ, Kim S-K, Lee HJ, Lee S-J, Chang Y (2012) Working memory impairment in fibromyalgia patients associated with altered frontoparietal memory network. PLoS ONE 7:e37808. doi: 10.1371/journal.pone.0037808 CrossRefPubMedCentralPubMedGoogle Scholar
  62. 62.
    Schmidt-Wilcke T, Wood P, Lurding R (2010) Schmerz und aufmerksamkeit: Kognitive defizite bei fibromyalgiepatienten (Cognitive impairment in patients suffering from fibromyalgia. An underestimated problem). Der Schmerz 24:46–53CrossRefPubMedGoogle Scholar
  63. 63.
    Kindler LL, Bennett RM, Jones KD (2011) Central sensitivity syndromes: mounting pathophysiologic evidence to link fibromyalgia with other common chronic pain disorders. Pain Manag Nurs 12:15–24CrossRefPubMedCentralPubMedGoogle Scholar
  64. 64.
    Russell IJ, Larson AA (2009) Neurophysiopathogenesis of fibromyalgia syndrome: a unified hypothesis. Rheum Dis Clin N Am 35:421–435CrossRefGoogle Scholar
  65. 65.
    Smith HS, Harris R, Clauw D (2011) Fibromyalgia: an afferent processing disorder leading to a complex pain generalized syndrome. Pain Physician 14:E217–E245PubMedGoogle Scholar
  66. 66.
    Woolf CJ (2011) Central sensitization: implications for the diagnosis and treatment of pain. Pain 152(Suppl 3):S2–S15CrossRefPubMedCentralPubMedGoogle Scholar
  67. 67.
    Yunus MB (2007) Role of central sensitization in symptoms beyond muscle pain, and the evaluation of a patient with widespread pain. Baillieres Best Pract Res Clin Rheumatol 21:481–497CrossRefGoogle Scholar
  68. 68.
    Yunus MB (2007) Fibromyalgia and overlapping disorders: the unifying concept of central sensitivity syndromes. Semin Arthritis Rheum 36:339–356CrossRefPubMedGoogle Scholar
  69. 69.
    Ceko M, Bushnell MC, Gracely RH (2012) Neurobiology underlying fibromyalgia symptoms. Pain Res Treat 2012:1–8. doi: 10.1155/2012/585419 CrossRefGoogle Scholar
  70. 70.
    Seminowicz DA, Davis KD (2007) Pain enhances functional connectivity of a brain network by performance of a cognitive task. J Neurophysiol 97:3651–3659CrossRefPubMedGoogle Scholar
  71. 71.
    Peterson BS, Skudlarski P, Gatenby JC, Zhang H, Anderson AW, Gore JC (1999) An fMRI study of Stroop word-color interference: evidence for cingulate subregions subserving multiple distributed attentional systems. Biol Psychiatry 45:1237–1258CrossRefPubMedGoogle Scholar
  72. 72.
    Ravnkilde B, Videbech P, Rosenberg R, Gjedde A, Gade A (2002) Putative tests of frontal lobe function: a PET-study of brain activation during Stroop’s Test and verbal fluency. J Clin Exp Neuropsychol 24:534–547CrossRefPubMedGoogle Scholar
  73. 73.
    Luerding R, Weigand T, Bogdahn U, Schmidt-Wilcke T (2008) Working memory performance is correlated with local brain morphology in the medial frontal and anterior cingulate cortex in fibromyalgia patients: structural correlates of pain–cognition interaction. Brain 131:3222–3231CrossRefPubMedGoogle Scholar
  74. 74.
    Audhya T, Adams JB, Johansen L (2012) Correlation of serotonin levels in CSF, platelets, plasma, and urine. Biochim Biophys Acta 1820:1496–1501CrossRefPubMedGoogle Scholar
  75. 75.
    Wood PB, Patterson JC II, Sunderland JJ, Tainter KH, Glabus MF, Lilien DL (2007) Reduced presynaptic dopamine activity in fibromyalgia syndrome demonstrated with positron emission tomography. J Pain 8:51–58CrossRefPubMedGoogle Scholar
  76. 76.
    Bruck A, Aalto S, Nurmi E, Bergman J, Rinne JO (2005) Cortical 6-[18F]fluoro-L-dopa uptake and frontal cognitive functions in early Parkinson’s disease. Neurobiol Aging 26:891–898CrossRefPubMedGoogle Scholar
  77. 77.
    Nagano-Saito A, Kato T, Arahata Y, Washimi Y, Nakamura A, Abe Y, Yamada T, Iwai K, Hatano K, Kawasumi Y, Kachi T, Dagher A, Ito K (2004) Cognitive- and motor-related regions in Parkinson’s disease: FDOPA and FDG PET studies. Neuroimage 22:553–561CrossRefPubMedGoogle Scholar
  78. 78.
    Ellis KA, Nathan PJ (2001) The pharmacology of human working memory. Int J Neuropsychopharmacol 4:299–313PubMedGoogle Scholar
  79. 79.
    Fitzcharles M-A, Ste-Marie PA, Goldenberg DL, Pereira JX, Abbey S, Choinière M, Ko G, Moulin DE, Panopalis P, Proulx J, Shir Y, the National Fibromyalgia Guideline Advisory Panel (2013) 2012 Canadian Guidelines for the diagnosis and management of fibromyalgia syndrome: executive summary. Pain Res Manag 18:119–126PubMedCentralPubMedGoogle Scholar
  80. 80.
    Stahl SM (2009) Fibromyalgia—pathways and neurotransmitters. Hum Psychopharmacol Clin Exp 24:S11–S17CrossRefGoogle Scholar
  81. 81.
    Volkow ND, Swanson JM (2013) Adult attention deficit—hyperactivity disorder. N Engl J Med 369:1935–1944CrossRefPubMedGoogle Scholar
  82. 82.
    Reyero F, Ponce G, Rodriguez-Jimenez R, Fernandez-Dapica P, Taboada D, Martin V, Navio M, Jimeniz-Arriero MA, Hoenicka J, Palomo T (2011) High frequency of childhood ADHD history in women with fibromyalgia. Eur Psychiatry 26:482–483CrossRefPubMedGoogle Scholar
  83. 83.
    Malt EA, Olafsson S, Aakvaag A, Lund A, Ursin H (2003) Altered dopamine D2 receptor function in fibromyalgia patients: a neuroendocrine study with buspirone in women with fibromyalgia compared to female population based controls. J Affect Disord 75:77–82CrossRefPubMedGoogle Scholar
  84. 84.
    Wood PB, Schweinhardt P, Jaeger E, Dagher A, Hakyemez H, Rabiner EA, Bushnell MC, Chizh BA (2007) Fibromyalgia patients show an abnormal dopamine response to pain. Eur J Neurosci 25:3576–3582CrossRefPubMedGoogle Scholar
  85. 85.
    Holman AJ, Myers RR (2005) A randomized, double-blind, placebo-controlled trial of pramipexole, a dopamine agonist, in patients with fibromyalgia receiving concomitant medications. Arthritis Rheum 52:2495–2505CrossRefPubMedGoogle Scholar
  86. 86.
    Young JL, Redmond JC (2007) Fibromyalgia, chronic fatigue, and adult attention deficit hyperactivity disorder in the adult: a case study. Psychopharmacol Bull 40:118–126PubMedGoogle Scholar
  87. 87.
    Young JL (2013) Chronic fatigue syndrome: 3 cases and a discussion of the natural history of attention-deficit/hyperactivity disorder. Postgrad Med 125:162–168CrossRefPubMedGoogle Scholar
  88. 88.
    Katz RS, Bond H, Leavitt F (2013) Methylphenidate improves concentration, energy and mood in fibromyalgia [abstract 1108]. Arthritis Rheum 65(Suppl):S470Google Scholar
  89. 89.
    Bradley LA, Alberts KR (1999) Psychological and behavioral approaches to pain management for patients with rheumatic disease. Rheum Dis Clin N Am 25:215–232CrossRefGoogle Scholar
  90. 90.
    Leavitt F, Katz RS (2009) Normalizing memory recall in fibromyalgia with rehearsal: a distraction-counteracting effect. Arthritis Rheum 61:740–744CrossRefPubMedGoogle Scholar
  91. 91.
    Busch AJ, Webber SC, Brachaniec M, Bidonde J, Dal Bello-Haas V, Danyliw AD, Overend TJ, Richards RS, Sawant A, Schachter CL (2011) Exercise therapy for fibromyalgia. Curr Pain Headache Rep 15:358–367CrossRefPubMedCentralPubMedGoogle Scholar
  92. 92.
    Etnier JL, Chang Y-K (2009) The effect of physical activity on executive function: a brief commentary on definitions, measurement issues, and the current state of the literature. J Sport Exerc Psychol 31:469–483Google Scholar
  93. 93.
    Etnier JL, Karper WB, Gapin JI, Barella LA, Chang YK, Murphy KJ (2009) Exercise, fibromyalgia, and fibrofog: a pilot study. J Phys Act Health 6:239–246PubMedGoogle Scholar

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© Springer-Verlag Berlin Heidelberg 2015

Authors and Affiliations

  1. 1.Department of Psychiatry and Department of Preventive Medicine, Rush Medical CollegeRush University Medical CenterChicagoUSA
  2. 2.Section of Rheumatology, Department of Internal Medicine, Rush Medical CollegeRush University Medical CenterChicagoUSA

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