Audiological monitoring.
Audiological monitoring was performed in our Institution by the same
team of physicians and audiologists. At least a yearly evaluation was
scheduled in patients with normal hearing whereas a six-monthly
evaluation was performed in patients with a hearing loss diagnosis.
Accordingly, with our previous paper [15], audiological evaluation
included otoscopy and tympanometry and acoustic reflex measurements in
order to exclude middle ear pathology (Grason Stadler, Eden Prairie
Minn., USA).
Pure-tone air conduction thresholds were evaluated at frequencies of
0.25, 0.5, 1, 2, 4 and 8 kHz in decibel hearing level (dB HL). Pure-tone
bone conduction thresholds were assessed at frequencies of 0.25, 0.5, 1,
2 and 4 kHz to determine the type of the hearing impairment (i.e.
conductive, sensorineural or mixed). Visual reinforcement audiometry was
performed in a calibrated sound field or via earphones for children
6–30 months of age. Sound-field results reflect hearing in the better
ear if there is a difference in hearing between ears. In general,
frequencies at 0.5, 1, 2 and 4 kHz were obtained when visual
reinforcement audiometry was used to measure hearing. Conditioned play
audiometry (train show) was used for children able to cooperate (30
months to 5 years). Standard pure-tone audiometry was used for older
children (>5 years) under standard conditions using an
Amplaid 319 audiometer (Amplaid Inc., Milan, Italy) in a double-walled,
sound-proof room testing conventional frequency ranges from 0.25 to 8
kHz (see www.asha.org/policy).
Auditory brain response (ABR) evaluation consisted of threshold searches
using 100-µs clicks as well as tone bursts at 1, 2 and 4 kHz (GN
Otometrics, Copenhagen, Denmark). Responses were obtained by averaged
electroencephalic responses via three scalp electrodes positioned during
sleep. We considered these examinations normal as their threshold was 20
dB HL bilaterally. Patients who had their baseline evaluations recorded
by ABR where subsequently monitored by behavioural audiometry, and thus
no patient underwent exclusive ABR evaluation.
Audiological records were examined and classified according to the SIOP
(International Society of Pediatric Oncology) Boston ototoxicity scale
(grade 0–4). Families of children received adequate and comprehensible
information about side effects of the administered therapy and scheduled
audiological monitoring and gave their written consent to perform the
tests. All protocol procedures were approved by the Ethical Committee of
Fondazione Policlinico Universitario A. Gemelli IRCCS (Number of
protocols: 0019971/20- ID 3074).