Validation of a portable tympanometer for use in primary care

Objective — to determine the accuracy of a handheld, portable tympanometer, the microtymp, in comparison with a reference instrument, the AR 85 tympanometer and with the gold standard: presence or absence of middle-ear fluid. Design — comparison of results from the microtymp with results from the reference tympanometer, the AR 85 and the gold standard. Setting — University Children's Hospital, Utrecht and the General Hospital, Overvecht, Utrecht. Subjects — 142 children (284 ears) aged between 6 months and 12 years, who were referred by their General Practitioner or Ear, Nose and Throat surgeon for myringotomy and/or tympanostomy tube insertion. Main outcome measures — tympanometry with the AR 85 and presence or absence of middle-ear fluid. Results — In 243 ears, of the included 284 ears, the test results of the microtymp were compared with those of the reference instrument, the AR 85 tympanometer. Sensitivity 0.96 (95% C.I., 0.93, 0.99), Specificity 0.81 (95% C.I.: 0.71, 0.91). In 233 ears, of the included 284 ears, the test results of the microtymp were compared with the gold standard. Sensitivity 0.94 (95% C.I.: 0.90, 0.98), specificity 0.48 (95% C.I.: 0.37, 0.59). Conclusion — The microtymp is a valid instrument for diagnosing middle-ear effusions. The results of the microtymp are highly comparable with traditional tympanometers: high sensitivity and much lower specificity. Use in primary care can increase diagnostic accuracy of otitis media with effusion (OME) and makes follow-up possible. This will help to discriminate between those OME cases who need further treatment and those who will resolve spontaneously.