title: Audiometric asymmetry and tinnitus laterality.
abstract: OBJECTIVE
  To identify an optimal audiometric asymmetry index for predicting tinnitus laterality.
  
  
  METHODS
  Retrospective medical record review.
  
  
  METHODS
  Data from adult tinnitus patients (80 men and 44 women) were extracted for demographic, audiometric, tinnitus laterality, and related information. The main measures were sensitivity, specificity, positive predictive value (PPV), and receiver operating characteristic (ROC) curves.
  
  
  RESULTS
  Three audiometric asymmetry indices were constructed using one, two, or three frequency elements to compute the average interaural threshold difference (aITD). Tinnitus laterality predictive performance of a particular index was assessed by increasing the cutoff or minimum magnitude of the aITD from 10 to 35 dB in 5-dB steps to determine its ROC curve. Single frequency index performance was inferior to the other two (P < .05). Double and triple frequency indices were indistinguishable (P > .05). Two adjoining frequency elements with aITD ≥ 15 dB performed optimally for predicting tinnitus laterality (sensitivity = 0.59, specificity = 0.71, and PPV = 0.76). Absolute and relative magnitudes of hearing loss in the poorer ear were uncorrelated with tinnitus distress.
  
  
  CONCLUSIONS
  An optimal audiometric asymmetry index to predict tinnitus laterality is one whereby 15 dB is the minimum aITD of two adjoining frequencies, inclusive of the maximal ITD. Tinnitus laterality dependency on magnitude of interaural asymmetry may inform design and interpretation of neuroimaging studies. Monaural acoustic tinnitus therapy may be an initial consideration for asymmetric hearing loss meeting the criterion of aITD ≥ 15 dB.
authors.affiliation: Department of Otolaryngology-Head and Neck Surgery, Vanderbilt University Medical Center, Vanderbilt University, Nashville, Tennesee, USA.
authors.forename: Betty S
authors.initials: BS
authors.lastname: Tsai
authors.forename: Robert W
authors.initials: RW
authors.lastname: Sweetow
authors.forename: Steven W
authors.initials: SW
authors.lastname: Cheung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001301:Audiometry, Pure-Tone / Q000379:methods*; D005260:Female; D005500:Follow-Up Studies; D007839:Functional Laterality / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017084:Otoacoustic Emissions, Spontaneous / Q000502:physiology*; D011237:Predictive Value of Tests; D012372:ROC Curve; D012189:Retrospective Studies; D014012:Tinnitus / Q000175:diagnosis / Q000503:physiopathology*; D055815:Young Adult