Inherited low-frequency hearing loss. A new mixed conductive/sensorineural entity?

Eighteen patients with low-frequency hearing loss ( LFHL ), 10 males and 8 females with an average age of 27 years, were examined in order to classify their hearing loss, i.e. to find the topical site of the hearing lesion and to evaluate the aetiology of the hearing disorder. Based on extensive audiological test procedures, the patients could be subdivided into two groups: Group A comprising 11 patients with true sensorineural hearing impairment caused by various well-known aetiologies, and group B comprising 7 patients in whom no classification of the LFHL could be made because of conflicting test results. In group B, family investigations demonstrated that the hearing loss could be ascribed to inheritance in 6 of the patients. The clinical findings and outcome of the audiological tests are discussed and, on the basis of this and a comparison with other rare entities, a hypothesis of a new, unrecognized entity within LFHL is suggested.