Speech recognition and frequency of hearing loss in patients treated for cancer in childhood

The aim of this study was to characterize the audiological profile accompanying oncological treatment in patients who had cancer in childhood and had been free of oncological treatment for at least 8 years. Our main interest lay in identifying the affected frequencies that interfered with speech intelligibility (SI) in those who had acquired hearing loss after treatment.

Two hundred patients who had cancer in childhood were evaluated. Diagnosis was made at the mean age of 6 years old, and hearing evaluation was performed at a mean age of 21 years. Fifty-one of these patients received chemotherapy without cisplatin, carboplatin or head and neck radiotherapy; 64 received cisplatin without head and neck radiotherapy; 75 received head and neck radiotherapy without cisplatin; and 10 received both head and neck radiotherapy and cisplatin chemotherapy. All patients underwent pure tone audiometry and speech audiometry.

Patients who had hearing loss primarily had bilateral symmetric sensorineural hearing loss. Although the average SI for ears with hearing loss in the frequency range from 4 to 8 kHz was normal, the Kruskall-Wallis test showed a significant difference between ears without hearing loss and those with hearing loss between 4 and 8 kHz. The average SI score in ears with hearing loss between 1 and 8 kHz was significantly different from all other ears.

Hearing loss involving frequencies at and above 4 kHz determines a decline in SI.