Audiologic and vestibular assessment in patients with β-thalassemia major receiving long-term transfusion therapy

Life-long transfusion therapy with chelators is a treatment choice for patients with β-thalassemia major. Some investigators have proposed auditory impairment related to the use of deferoxamine, but the mechanisms remain unclear and whether or not deferiprone has similar side effects needs to be evaluated.

Thirty-seven patients with β-thalassemia major who received regular transfusion in our hospital were enrolled. Chelation agents, including deferoxamine and deferiprone, were used. To assess audiologic function, otoscopy, pure tone audiometry (PTA), tympanometry, transient evoked oto-acoustic emission (TEOAE), and auditory brainstem response (ABR) were conducted. Bithermal caloric test was performed to evaluate vestibular function.

All of the 37 patients had normal findings on otoscopic evaluation and their tympanograms were type A. Thirteen patients (35.1%) had hearing impairment at one or more frequencies as detected by PTA. Compared to those without hearing impairment, patients with hearing impairment had lower serum ferritin levels (P = 0.01). Seven of 21 patients (33.3%) failed to pass the TEOAE, while 13 (61.9%) had abnormal ABR findings. Sixteen patients (80%) had canal paresis in the caloric test.

The incidence of auditory impairment and vestibular dysfunction was high in patients with β-thalassemia major receiving long-term transfusion therapy. Potential lesions of auditory impairment may exist anywhere along the auditory pathway, from the inner ear to the brainstem. Lower serum ferritin levels may be associated with hearing impairment. Therefore, regular check-ups of serum ferritin levels and periodic audiologic assessment are mandatory.