OBJECTIVESTo characterize initial central nervous system responses to olfactory administration of homeopathic remedies as biomarkers for subsequently exceptional, simillimum-like clinical outcomes at a systemic level (i.e., both locally and globally).DESIGNDouble-blinded, randomized, placebo-controlled clinical trial.SETTINGA private homeopathic clinic in Phoenix, AZ, and a university laboratory in Tucson, AZ.PATIENTSSixty-two (62) persons with physician-confirmed fibromyalgia (FM) (mean age, 49 years; 94% women) enrolled; 53 completed the 3-month assessment visit. Exceptional responders (n = 6, 23% of active treatment group; none on placebo) were those with improvements in the top one-third for both tender point pain and global health ratings after 3 months.INTERVENTIONPatients took daily oral doses of treatment solution in LM (1/50,000 dilution) potency (active group received individualized remedy; placebo group received plain solvent). Dependent measures: Baseline and 3-month difference scores for initial prefrontal electroencephalographic alpha frequency cordance (EEG-C, a correlate of functional brain activity) during 16 pairs of randomized, double-blinded bottle sniffs (treatment minus control solutions).RESULTSExceptional responders versus other patients exhibited significantly more negative initial EEG-C difference scores at prefrontal sites. Right prefrontal cordance findings correlated with subsequently reduced pain (r = 0.85, p = 0.03), better global health (r =-0.73, p = 0.10), and trait absorption (genetically determined ability to focus attention selectively and fully) (r = 0.91, p = 0.012).CONCLUSIONSThese observations suggest prefrontal EEG-C as an early biomarker of individualized homeopathic medicine effects in patients with FM who later exhibit exceptional outcomes. Prefrontal cortex controls executive function, including ability to redirect attention. Interactions between executive function, absorption, and the simillimum remedy could facilitate exceptional responses.