The absence of resting-state high-gamma cross-frequency coupling in patients with tinnitus

Min Hee Ahn, Sung Kwang Hong, Byoung-Kyong Min

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17 Citations (Scopus)


Tinnitus is a psychoacoustic phantom perception of currently unknown neuropathology. Despite a growing number of post-stimulus tinnitus studies, uncertainty still exists regarding the neural signature of tinnitus in the resting-state brain. In the present study, we used high-gamma cross-frequency coupling and a Granger causality analysis to evaluate resting-state electroencephalographic (EEG) data in healthy participants and patients with tinnitus. Patients with tinnitus lacked robust frontal delta-phase/central high-gamma-amplitude coupling that was otherwise clearly observed in healthy participants. Since low-frequency phase and high-frequency amplitude coupling reflects inter-regional communication during cognitive processing, and given the absence of frontal modulation in patients with tinnitus, we hypothesized that tinnitus might be related to impaired prefrontal top-down inhibitory control. A Granger causality analysis consistently showed abnormally pronounced functional connectivity of low-frequency activity in patients with tinnitus, possibly reflecting a deficiency in large-scale communication during the resting state. Moreover, different causal neurodynamics were characterized across two subgroups of patients with tinnitus; the T1 group (with higher P300 amplitudes) showed abnormal frontal-to-auditory cortical information flow, whereas the T2 group (with lower P300 amplitudes) exhibited abnormal auditory-to-frontal cortical information control. This dissociation in resting-state low-frequency causal connectivity is consistent with recent post-stimulus observations. Taken together, our findings suggest that maladaptive neuroplasticity or abnormal reorganization occurs in the auditory default mode network of patients with tinnitus. Additionally, our data highlight the utility of resting-state EEG for the quantitative diagnosis of tinnitus symptoms and the further characterization of tinnitus subtypes.

Original languageEnglish
Pages (from-to)63-73
Number of pages11
JournalHearing Research
Publication statusPublished - 2017 Dec

Bibliographical note

Funding Information:
This work was supported by the Basic Science Research program (grant numbers 2015R1A1A1A05027233 to BKM; 2017M3A9G1027932 to SKH), the ICT R&D program of MSIP/Institute for Information & Communications Technology Promotion (IITP; grant number 2017-0-00432 to BKM), and the Information Technology Research Center (ITRC) support program (grant number IITP-2017-2016-0-00464 to BKM) supervised by the IITP, which are funded by the Korean government (MSIT) through the National Research Foundation of Korea . The authors declare that they have no competing interests.

Publisher Copyright:
© 2017 The Authors


  • Causality
  • Cross-frequency coupling
  • Electroencephalogram
  • Phase-amplitude coupling
  • Resting state
  • Tinnitus

ASJC Scopus subject areas

  • Sensory Systems


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