Audiologic and metabolic findings in 90 patients with fluctuant hearing loss.

Fluctuant hearing loss is a common occurrence. It is difficult to diagnose in its early stages when hearing thresholds are near normal and the only complaints the patient has are of fullness and tinnitus. Audiologic tests are helpful in confirming the diagnosis. Impedance measurements are an accurate assessment of middle ear status and can assist in localizing the fullness experienced by these patients. Site of lesion tests and discrimination scores at various sensation levels are sensitive indexes of disease activity. Observations during medical treatment of 90 patients with metabolic dysfunction (hyperlipoproteinemia: hypoglycemia; hypothyroidism) suggest that discrimination scores fluctuate more widely than do pure tone thresholds over a period of time. Thirty patients were given complete audiologic testing after dietary management and treatment. All reported relief from tinnitus and fullness, and 15 or 50% showed improved audiograms and discrimination scores. Any change in the energy reserve or metabolic rate of the inner ear by a systemic metabolic dysfunction can contribute to or cause sensorineural hearing loss. Energy flow from metabolic sources is needed to transduce the acoustic stimuli into neural excitation patterns. The presence of any systemic metabolic dysfunction can be expected to contribute to and cause fluctuant hearing loss.